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Topics - Geoffw

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A Logarithmic Map of the Entire Observable Universe

Among the scientific community, it's widely believed that so far humans have only discovered about 5% of the universe.

Yet, despite knowing about just a fraction of what's out there, we've still managed to discover galaxies billions of light-years away from Earth.

This graphic by Pablo Carlos Budassi provides a logarithmic map of the entire known universe, using data by researchers at Princeton University and updated as of May 2022.

CLICK HERE:
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THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 569 2022 July 3


We're delighted that the Society for Popular Astronomy's free Electronic News Bulletins have gained many hundreds of subscribers since we first issued them more than 23 years ago!

They remain free, but if you are not already a member of the SPA, we hope you will consider joining, and supporting the UK's liveliest astronomical society, with members worldwide. You can easily sign up online. https://www.popastro.com/main_...

And now, here is our latest round-up of news.

PERSEVERANCE STUDIES WILD WINDS OF JEZERO CRATER
NASA

During its first couple hundred days in Jezero Crater, NASA's Perseverance Mars rover saw some of the most intense dust activity ever witnessed by a mission sent to the Red Planet's surface. Not only did the rover detect hundreds of dust-bearing whirlwinds called dust devils, Perseverance captured the first video ever recorded of wind gusts lifting a massive Martian dust cloud. The new findings enable scientists to better understand dust processes on Mars and contribute to a body of knowledge that could one day help them predict the dust storms that Mars is famous for - and that pose a threat to future robotic and human explorers. The study authors found that at least four whirlwinds pass Perseverance on a typical Martian day and that more than one per hour passes by during a peak hourlong period just after noon. The rover's cameras also documented three occasions in which wind gusts lifted large dust clouds, something the scientists call "gust-lifting events." The biggest of these created a massive cloud covering 4 square kilometres. A key objective for Perseverance's mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet's geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith (broken rock and dust).

HOW AURORA ON MARS IS FORMED
University of Iowa

Physicists have studied discrete aurora, a light-in-the-sky display that occurs mostly during the night in the southern hemisphere of Mars . While scientists have known about discrete aurora on Mars-which also occur on Earth -- they did not know how they formed. That's because Mars does not have a global magnetic field like Earth, which is a main trigger for aurora, also called the northern and southern lights on our planet. Instead, the physicists report, discrete aurora on Mars are governed by the interaction between the solar wind -- the constant jet of charged particles from the Sun -- and magnetic fields generated by the crust at southern latitudes on Mars. It's the nature of this localized interaction between the solar wind and the crustal magnetic fields that lead to discrete aurora, the scientists find. The findings come from more than 200 observations of discrete aurora on Mars by the NASA-led Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft.

FIRST ANALYSIS OF ROCKS FROM ASTEROID RYUGU
University of Chicago

In 2018, Hayabusa2 landed atop a moving asteroid named Ryugu and collected particles from above and below its surface. After spending a year and a half orbiting the asteroid, it returned to Earth with a sealed capsule containing about five grams of dust and rock. Scientists around the world have been eagerly anticipating the unique sample -- one that could help redefine our understanding of how planets evolve and how our solar system formed. Scientists are particularly excited because these particles would never have reached Earth without the protective barrier of a spacecraft. The rock is similar to a class of meteorites known as "Ivuna-type carbonaceous chondrites. These rocks have a similar chemical composition to what we measure from the Sun and are thought to date back to the very beginnings of the solar system approximately four-and-a-half billion years ago -- before the formation of the Sun, the Moon and Earth. Back then, all that existed was a gigantic, rotating cloud of gas. Scientists think that most of that gas was pulled into the centre and formed the star we know as the Sun. As the remnants of that gas expanded into a disk and cooled, it transformed into rocks, which still float around the solar system today; it appears Ryugu may be one of them. Scientists said the fragments show signs of having been soaked in water at some point. Using radioisotope dating, they estimated that Ryugu was altered by water circulation only about five million years after the solar system formed. These findings are particularly interesting to researchers because they hint at similar formation conditions between comets and some asteroids such as Ryugu. The scientists noted that a percentage of the find will be set aside so that we can analyze them in the future with more advanced technology -- much as we did with lunar samples from Apollo. This mission is the first of several international missions that will bring back samples from another asteroid named Bennu, as well as unexplored areas on our moon, Mars, and Mars' moon Phobos. This should all be taking place in the next 10 to 20 years.

LARGE NUMBER OF BROWN DWARFS DISCOVERED
University of Bern

Brown dwarfs are mysterious astronomical objects that fill the gap between the heaviest planets and the lightest stars, with a mix of stellar and planetary characteristics. Due to this hybrid nature, these puzzling objects are crucial to improve our understanding of both stars and giant planets. Brown dwarfs orbiting a parent star from sufficiently far away are particularly valuable as they can be directly photographed -- unlike those that are too close to their star and are thus hidden by its brightness. This provides scientists with a unique opportunity to study the details of the cold, planet-like atmospheres of brown dwarf companions. However, despite remarkable efforts in the development of new observing technologies and image processing techniques, direct detections of brown dwarf companions to stars have remained rather sparse, with only around 40 systems imaged in almost three decades of searches. Researchers have now directly imaged four new brown dwarfs. Wide-orbit brown dwarf companions are rare to start with, and detecting them directly poses huge technical challenges since the host stars completely blind our telescopes. Most surveys conducted so far have been blindly targeting random stars from young clusters. An alternative approach to increase the number of detections is to only observe stars that show indications of an additional object in their system. For example, the way a star moves under the gravitational tug of a companion can be an indicator of the existence of that companion, whether it is a star, a planet or something in between. The team developed the COPAINS tool which predicts the types of companions that could be responsible for observed anomalies in stellar motions. Applying the COPAINS tool the research team carefully selected 25 nearby stars that seemed promising for the direct detection of hidden, low-mass companions based on data from the Gaia spacecraft of the European Space Agency (ESA). Using then the SPHERE planet-finder at the Very Large Telescope in Chile to observe these stars, they successfully detected ten new companions with orbits ranging from that of Jupiter to beyond that of Pluto, including five low-mass stars, a white dwarf (a dense stellar remnant), and a remarkable four new brown dwarfs. These findings significantly advance the number of known brown dwarfs orbiting stars from large distances, with a major boost in detection rate compared to any previous imaging survey. While for now this approach is mostly limited to signatures from brown dwarf and stellar companions, future phases of the Gaia mission will push these methods to lower masses and allow for the discovery of new giant exoplanets.

EVIDENCE OF GALACTIC METAL SHROUDED IN DUST
University of California - Irvine

A thorough understanding of galaxy evolution depends in part on an accurate measurement of the abundance of metals in the intergalactic medium -- the space between stars -- but dust can impede observations in optical wavelengths. An international team of astronomers uncovered evidence of heavier elements in local galaxies -- found to be deficient in earlier studies -- by analysing infrared data gathered during a multiyear campaign. To determine the abundance of gas-phase metals in the intergalactic medium, the astronomers sought to acquire data on the ratios of proxies, oxygen and nitrogen, because infrared emissions from these elements are less obscured by galactic dust. Observing this process in infrared wavelengths is a challenge for astronomers because water vapour in Earth's atmosphere blocks radiation on this part of the electromagnetic spectrum, making measurements from even the highest-altitude ground telescopes -- like those at the Keck Observatory in Hawaii -- insufficient. Part of the dataset used by the team came from the now-retired Herschel Space Telescope, but Herschel was not equipped with a spectrometer capable of reading a specific emission line that the UCI-led team needed for its study. The researchers' solution was to take to the skies -- reaching more than 45,000 feet above sea level -- in the Stratospheric Observatory for Infrared Astronomy, NASA's Boeing 747 equipped with a 2.5-meter telescope. By analysing infrared emissions, the researchers were able to compare the metallicity of their target ultraluminous infrared galaxies with less dusty galaxies with similar mass and star formation rates. Chartab explained that these new data show that ultraluminous infrared galaxies are in line with the fundamental metallicity relation determined by stellar mass, metal abundance and star formation rate. The new data further show that the underabundance of metals derived from optical emission lines is likely due to "heavy dust obscuration associated with starburst," according to the paper.

SUPERMASSIVE BLACK HOLES INSIDE OF DYING GALAXIES
National Institutes of Natural Sciences

Astronomers used a database combining observations from the best telescopes in the world to detect the signal from the active supermassive black holes of dying galaxies in the early Universe. The appearance of these active supermassive black holes correlates with changes in the host galaxy, suggesting that a black hole could have far reaching effects on the evolution of its host galaxy. The Milky Way includes stars of various ages, including stars still forming. But in some other galaxies, known as elliptical galaxies, all of the stars are old and about the same age. This indicates that early in their histories elliptical galaxies had a period of prolific star formation that suddenly ended. Why this star formation ceased in some galaxies but not others is not well understood. One possibility is that a supermassive black hole disrupts the gas in some galaxies, creating an environment unsuitable for star formation. To test this theory, astronomers look at distant galaxies. Due to the finite speed of light, it takes time for light to travel across the void of space. The light we see from an object 10 billion light-years away had to travel for 10 billion years to reach Earth. Thus the light we see today shows us what the galaxy looked like when the light left that galaxy 10 billion years ago. So looking at distant galaxies is like looking back in time. But the intervening distance also means that distant galaxies look fainter, making study difficult.

To overcome these difficulties an international team used the Cosmic Evolution Survey (COSMOS) to sample galaxies 9.5-12.5 billion light-years away. COSMOS combines data taken by world leading telescopes, including the Atacama Large Millimeter/submillimeter Array (ALMA) and the Subaru Telescope. COSMOS includes radio wave, infrared light, visible light, and x-ray data. The team first used optical and infrared data to identify two groups of galaxies: those with ongoing star formation and those where star formation has stopped. The x-ray and radio wave data signal-to-noise ratio was too weak to identify individual galaxies. So the team combined the data for different galaxies to produce higher signal to noise ratio images of "average" galaxies. In the averaged images, the team confirmed both x-ray and radio emissions for the galaxies without star formation. This is the first time such emissions have been detected for distant galaxies more than 10 billion light-years away. Furthermore, the results show that the x-ray and radio emissions are too strong to be explained by the stars in the galaxy alone, indicating the presence of an active supermassive black hole. This black hole activity signal is weaker for galaxies where star formation is ongoing. These results show that an abrupt end in star formation in the early Universe correlates with increased supermassive black hole activity. More research is needed to determine the details of the relationship.


RAPID RADIO BURST SHOWS HOT SPACE BETWEEN GALAXIES
Cornell University

recently discovered, rare and persistent rapid-fire fast radio burst source -- sending out an occasional and informative cosmic ping from more than 3.5 billion light years away -- helps to reveal the secrets of the broiling hot space between the galaxies. Fast Radio Burst 20190520B -- a prolific repeating burst source -- was first observed in June 2019 by the Five-hundred-meter Aperture Spherical radio Telescope (FAST), in Ghizou province, southwest China. Astronomers generally consider this telescope as the spiritual successor to the now-defunct, Cornell University-built Arecibo Observatory in Puerto Rico. After FAST found the burst, scientists then pinpointed the burst's location using the Very Large Array, Socorro, New Mexico. What excites astronomers about the repeating fast radio bursts (FRBs) -- since they only burst once, generally speaking -- is that these quick-fire surges provide a pathway for scientists to comprehend the perplexing, mysterious and million-degree intergalactic medium. Four bursts were detected during the initial 24-second scan in 2019, according to the paper. Between April and September 2020, during follow-up observations, FAST detected 75.

Due to the rapidly repeating bursts, astronomers believe that FRB 20190520B may be quite young. It seems to reside in a complex plasma environment, like that expected in a young supernova remnant. So one possibility is that the highly active source may be a newborn, and if so, it paints an intriguing evolutionary picture of FRB sources, where young burst sources are associated with persistent radio emission. The persistent emission fades away as the burst repetition rate slows down. Astronomers usually assume that FRBs pass through only a modest amount of gas (free electrons) in their host galaxies, which makes counting electrons in the intergalactic medium an easier task. FRB 20190520B shows the opposite: It has encountered far more gas in its host galaxy than scientists expected, calling into question previous assumptions. Ultimately, astronomers want to know how the intergalactic medium is formed. Astronomers want to deconstruct how many free electrons are in the intergalactic medium, because it has been extremely difficult to study.


NUSTAR STUDIES X-RAY UNIVERSE FOR 10 YEARS
NASA

NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) is turning 10. Launched on June 13, 2012, this space telescope detects high-energy X-ray light and studies some of the most energetic objects and processes in the Universe, from black holes devouring hot gas to the radioactive remains of exploded stars. Here are some of the ways NuSTAR has opened our eyes to the X-ray Universe over the last decade. Different colours of visible light have different wavelengths and different energies; similarly, there is a range of X-ray light, or light waves with higher energies than those human eyes can detect. NuSTAR detects X-rays at the higher end of the range. There aren't many objects in our solar system that emit the X-rays NuSTAR can detect, but the Sun does: Its high-energy X-rays come from microflares, or small bursts of particles and light on its surface. NuSTAR's observations contribute to insights about the formation of bigger flares, which can cause harm to astronauts and satellites. These studies could also help scientists explain why the Sun's outer region, the corona, is many times hotter than its surface.

NuSTAR has identified dozens of black holes hidden behind thick clouds of gas and dust. Visible light typically can't penetrate those clouds, but the high-energy X-ray light observed by NuSTAR can. This gives scientists a better estimate of the total number of black holes in the Universe. In recent years scientists have used NuSTAR data to find out how these giants become surrounded by such thick clouds, how that process influences their development, and how obscuration relates to a black hole's impact on the surrounding galaxy. NuSTAR is a kind of zombie hunter: It's deft at finding the undead corpses of stars. Known as neutron stars, these are dense nuggets of material left over after a massive star runs out of fuel and collapses. Though neutron stars are typically only the size of a large city, they are so dense that a teaspoon of one would weigh about a billion tons on Earth. Their density, combined with their powerful magnetic fields, makes these objects extremely energetic: One neutron star located in the galaxy M82 beams with the energy of 10 million Suns. During their lives, stars are mostly spherical, but NuSTAR observations have shown that when they explode as supernovae, they become an asymmetrical mess. The space telescope solved a major mystery in the study of supernovae by mapping the radioactive material left over by two stellar explosions, tracing the shape of the debris and in both cases revealing significant deviations from a spherical shape. Because of NuSTAR's X-ray vision, astronomers now have clues about what happens in an environment that would be almost impossible to probe directly. The NuSTAR observations suggest that the inner regions of a star are extremely turbulent at the time of detonation.

Bulletin compiled by Clive Down

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Astronomy / The Night Sky in July
July 01, 2022, 08:20:50 pm
All the bright planets make an appearance this month. The inferior planets, so called, Venus and Mercury lie low in the eastern sky before sunrise, with the former nicely tangled in the stars of the Hyades in early July. Jupiter lies near the celestial equator in Pisces and grows fat and bright and ideal for telescopic observing. Saturn, too, looks great in a telescope as it slowly grows bigger. This month also brings the largest Full Moon of the year. And don't forget about the Milky Way emerging in the darkening east-south-eastern sky after sunset. Turn your optics along this spectacular river of stars to glimpse the many clusters, nebulae, and star clouds in our part of the galaxy. Here's what's in the night sky this month...


TO FIND OUT MORE CLICK HERE
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THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 568 2022 June 19

We're delighted that the Society for Popular Astronomy's free Electronic News Bulletins have gained many hundreds of subscribers since we first issued them more than 23 years ago!
They remain free, but if you are not already a member of the SPA, we hope you will consider joining, and supporting the UK's liveliest astronomical society, with members worldwide. You can easily sign up online. https://www.popastro.com/main_...
And now, here is our latest round-up of news.

EARTH'S MAGNETIC POLES UNLIKELY TO FLIP
Lund University

The emergence of a mysterious area in the South Atlantic where the geomagnetic field strength is decreasing rapidly, has led to speculation that Earth is heading towards a magnetic polarity reversal. However, a new study that pieces together evidence stretching back 9,000 years, suggests that the current changes aren't unique, and that a reversal may not be in the cards after all. The Earth's magnetic field acts as an invisible shield against the life-threatening environment in space, and solar winds that would otherwise sweep away the atmosphere. However, the magnetic field is not stable, and at irregular intervals at an average of every 200,000 years polarity reversals happen. This means that the magnetic North and South poles swap places. During the past 180 years, Earth's magnetic field strength has decreased by about 10 percent. Simultaneously, an area with an unusually weak magnetic field has grown in the South Atlantic off the coast of South America. This area, where satellites have malfunctioned several times due to exposure to highly charged particles from the Sun, is called the South Atlantic Anomaly. These developments have led to speculation that we may be heading for a polarity reversal. However, the new study suggests this may not be the case. The results are based on analyses of burnt archaeological artifacts, volcanic samples and sediment drill cores, all of which carry information about the Earth's magnetic field. These include clay pots that have been heated up to over 580 degrees Celsius, volcanic lava that has solidified, and sediments that have been deposited in lakes or in the sea. The objects act as time capsules, and carry information about the magnetic field in the past. Using sensitive instruments, the researchers have been able to measure these magnetizations and recreate the direction and strength of the magnetic field at specific places and times. By studying how the magnetic field has changed, researchers can learn more about the underlying processes in the Earth's core that generate the field. The new model can also be used to date both archaeological and geological records, by comparing measured and modelled variations in the magnetic field. And reassuringly, it has led them to a conclusion regarding speculations about an imminent polarity reversal:

CHINA LAUNCHES 3RD CREWED MISSION TO TIANGONG SPACE STATION
CMSA

China has successfully launched another manned mission to its new space station, sending three astronauts who will continue construction work for six months, The team will live and work at the Tiangong Space Station's Tianhe core module for six months before returning to Earth in December. Tiangong means Heavenly Palace. This is the third crewed mission during the construction of the space station, which China plans to have fully crewed and operational by December 2022. The first crewed mission, a three-month stay by three other astronauts, was completed in September 2021. The second, Shenzhou-13, saw three astronauts spend six months in space for the first time. Six months is the standard mission duration for many countries -- but it is an important opportunity for Chinese astronauts to become accustomed to a long-term stay in space and help prepare future astronauts to do the same. Six space missions have been scheduled before the end of the year, including another crewed mission, two laboratory modules and two cargo missions. The modules will be assembled into a T-shaped structure, along with the Tianhe core cabin -- the main living space for the astronauts -- which will be expanded from 50 cubic metres to 110 cubic metres. At the end of the Shenzhou-14 mission, another three astronauts are expected to rotate and live with the crew for five to 10 days, bringing the number of Chinese astronauts in space at the same time to a record six.
Once construction is completed, the Tiangong space station is expected to last for 15 years. China plans to launch two crewed missions and two cargo missions to the station every year The Shenzhou-13 mission last year was a major step for the country's young space program, which is rapidly becoming one of the world's most advanced. China's space program was late to the game, only established in the early 1970s, years after American astronaut Neil Armstrong had already landed on the Moon. But the chaos of China's Cultural Revolution stopped the nation's space effort in its tracks -- and progress was postponed until the early 1990s. The government has since invested billions of dollars into the space program -- and the payoff has been evident. China successfully landed an exploratory rover on the Moon in December 2020 and one on Mars in May 2021. The first module of the Tiangong Space Station launched in April 2021. China's ambitions span years into the future, with grand plans for space exploration, research and commercialization. One of the biggest ventures will be building a joint China-Russia research station on the Moon's south pole by 2035 -- a facility that will be open to international participation.

THE VENUS CLOUD DISCONTINUITY
Spaceweather.com

The Venus Cloud Discontinuity is a relatively new discovery, photographed by Japan's Venus orbiter Akatsuki in 2016 and first spotted by JAXA scientist Javier Peralta. The massive structure cuts vertically across Venus's equator, stretching almost 5000 miles from end to end, and circles the planet faster than 200 mph, making one lap every ~5 Earth days. Researchers following up on the discovery soon stumbled onto another surprise. Older photographs of Venus showed it, too. The Cloud Discontinuity] is a recurrent phenomenon that has gone unnoticed since at least the year 1983. How do you overlook something so big? Visually, the Cloud Discontinuity is hidden underneath Venus's opaque cloudtops. To see it, you have to use an infrared filter, which reveals heat trickling up from below. Indeed, this is how amateurs are tracking the disturbance: Researchers still aren't sure what the Cloud Discontinuity is. Whatever it is, the structure might help solve a longstanding mystery: Why does Venus's atmosphere rotate so much faster than the planet itself? The hot, deadly air on Venus spins nearly 60 times faster than its surface, an effect known as "super-rotation." Venus's Cloud Discontinuity could be assisting the spin-up by transporting angular momentum from the deep atmosphere to the cloudtops.

GRAVITATIONAL WAVES DETECT NEW PARTICLES AROUND BLACK HOLES
Universiteit van Amsterdam

Clouds of ultralight particles can form around rotating black holes. A team of physicists now show that these clouds would leave a characteristic imprint on the gravitational waves emitted by binary black holes. Black holes are generally thought to swallow all forms of matter and energy surrounding them. It has long been known, however, that they can also shed some of their mass through a process called superradiance. While this phenomenon is known to occur, it is only effective if new, so far unobserved particles with very low mass exist in nature, as predicted by several theories beyond the Standard Model of particle physics. When mass is extracted from a black hole via superradiance, it forms a large cloud around the black hole, creating a so-called gravitational atom. Despite the immensely larger size of a gravitational atom, the comparison with sub-microscopic atoms is accurate because of the similarity of the black hole plus its cloud with the familiar structure of ordinary atoms, where clouds of electrons surround a core of protons and neutrons. In the new work, the researchers studied the gravitational equivalent of the so-called 'photoelectric effect'. In this well-known process, which for example is exploited in solar cells to produce an electric current, ordinary electrons absorb the energy of incident particles of light and are thereby ejected from a material -- the atoms 'ionize'. In the gravitational analogue, when the gravitational atom is part of a binary system of two heavy objects, it gets perturbed by the presence of the massive companion, which could be a second black hole or a neutron star. Just as the electrons in the photoelectric effect absorb the energy of the incident light, the cloud of ultralight particles can absorb the orbital energy of the companion, so that some of the cloud gets ejected from the gravitational atom. The team demonstrated that this process may dramatically alter the evolution of such binary systems, significantly reducing the time required for the components to merge with each other. Moreover, the ionization of the gravitational atom is enhanced at very specific distances between the binary black holes, which leads to sharp features in the gravitational waves that we detect from such mergers. Future gravitational wave interferometers -- machines similar to the LIGO and Virgo detectors that over the past few years have shown us the first gravitational waves from black holes -- could observe these effects. Finding the predicted features from gravitational atoms would provide distinctive evidence for the existence of new ultralight particles.

LIFECYCLE OF ANCESTOR GALAXY 'CITIES'
Kavli Institute for the Physics and Mathematics of the Universe

For the first time, researchers have created simulations that directly recreate the full life cycle of some of the largest collections of galaxies observed in the distant Universe 11 billion years ago. Cosmological simulations are crucial to studying how the Universe became the shape it is today, but many do not typically match what astronomers observe through telescopes. Most are designed to match the real Universe only in a statistical sense. Constrained cosmological simulations, on the other hand, are designed to directly reproduce the structures we actually observe in the Universe. However, most existing simulations of this kind have been applied to our local Universe, meaning close to Earth, but never for observations of the distant Universe. A team of researchers, were interested in distant structures like massive galaxy protoclusters, which are ancestors of present-day galaxy clusters before they could clump under their own gravity. They found current studies of distant protoclusters were sometimes oversimplified, meaning they were done with simple models and not simulations. Their result was COSTCO (COnstrained Simulations of The COsmos Field). Developing the simulation was much like building a time machine. Because light from the distant Universe is only reaching Earth now, the galaxies telescopes observe today are a snapshot of the past. In this sense, the researchers took snapshots of "young" grandparent galaxies in the Universe and then fast forwarded their age to study how clusters of galaxies would form. The light from galaxies the researchers used travelled a distance of 11 billion light-years to reach us.
Another important reason why the researchers created these simulations was to test the standard model of cosmology, that is used to describe the physics of the Universe. By predicting the final mass and final distribution of structures in a given space, researchers could unveil previously undetected discrepancies in our current understanding of the Universe. Using their simulations, the researchers were able to find evidence of three already published galaxy protoclusters and disfavor one structure. On top of that, they were able to identify five more structures that consistently formed in their simulations. This includes the Hyperion proto-supercluster, the largest and earliest proto-supercluster known today that is 5000 times the mass of our Milky Way galaxy, which the researchers found out it will collapse into a large 300 million light year filament. Their work is already being applied to other projects including those to study the cosmological environment of galaxies, and absorption lines of distant quasars to name a few.

RUSSIA ILLEGALLY PLANS TO RESTART GERMAN TELESCOPE

Russian space agency Roscosmos says it will restart a telescope shut down by Germany over Moscow's invasion of Ukraine. But a noted expert has warned that this might be dangerous to the instrument. The X-ray telescope, named eROSITA, works in tandem with a Russian instrument, the ART-XC, to scan distant galaxies in what was a joint German-Russian mission until Germany put its cooperation on ice over Russia's invasion. The telescope was launched into space from the Baikonur launch site in July 2019. However, the scientific director of the Spekr-RG project said that attempts to restart the telescope without German cooperation could be detrimental to the device itself. The recommissioning could take place only with Germany's consent; otherwise, the telescope would be in danger of breaking down. The Spektr-RG mission on which it is deployed along with the Russian telescope aims, among other things, to detect black holes.  Until eROSITA was put into sleep mode on February 26, two days after Russia started its invasion, Russian and German researchers had been able to jointly evaluate the data sent by the two devices. At the time it was shut down, eROSITA had completed four of its planned eight full-sky surveys. Data from the first four are still being evaluated by scientists.
Bulletin compiled by Clive Down
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FIRST OF ALL, THANKS EVERYONE for your concern and support. I'm fine now, just a little stressed, but I'll be ok.
For those of you who don't know what happened, I was robbed this morning at a petrol station in H'west.
I managed to pull myself together even though my hands were still shaking. I felt dizzy and I honestly think I was probably in shock.

My money was gone. I called the police who were quick on the scene and fantastic, they quickly called for an ambulance because my blood pressure and heart rate were so high.

The police asked me if I knew who did it and I said "yes it was pump number 3"   ;)
6
 
THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 567 2022 June 5
We're delighted that the Society for Popular Astronomy's free Electronic News Bulletins have gained many hundreds of subscribers since we first issued them more than 23 years ago!
They remain free, but if you are not already a member of the SPA, we hope you will consider joining, and supporting the UK's liveliest astronomical society, with members worldwide. You can easily sign up online. https://www.popastro.com/main_...
And now, here is our latest round-up of news.

WHY URANUS AND NEPTUNE ARE DIFFERENT COLOURS
Association of Universities for Research in Astronomy (AURA)

Astronomers may now understand why the similar planets Uranus and Neptune are different colours. Using observations from the Gemini North telescope, the NASA Infrared Telescope Facility, and the Hubble Space Telescope, researchers have developed a single atmospheric model that matches observations of both planets. The model reveals that excess haze on Uranus builds up in the planet's stagnant, sluggish atmosphere and makes it appear a lighter tone than Neptune. Neptune and Uranus have much in common -- they have similar masses, sizes, and atmospheric compositions -- yet their appearances are notably different. At visible wavelengths Neptune has a distinctly bluer colour whereas Uranus is a pale shade of cyan. Astronomers now have an explanation for why the two planets are different colours. New research suggests that a layer of concentrated haze that exists on both planets is thicker on Uranus than a similar layer on Neptune and 'whitens' Uranus's appearance more than Neptune's . If there were no haze in the atmospheres of Neptune and Uranus, both would appear almost equally blue. This conclusion comes from a model that an international team developed to describe aerosol layers in the atmospheres of Neptune and Uranus. Previous investigations of these planets' upper atmospheres had focused on the appearance of the atmosphere at only specific wavelengths. However, this new model, consisting of multiple atmospheric layers, matches observations from both planets across a wide range of wavelengths. The new model also includes haze particles within deeper layers that had previously been thought to contain only clouds of methane and hydrogen sulphide ices.
The team's model consists of three layers of aerosols at different heights. The key layer that affects the colours is the middle layer, which is a layer of haze particles (referred to in the paper as the Aerosol-2 layer) that is thicker on Uranus than on Neptune. The team suspects that, on both planets, methane ice condenses onto the particles in this layer, pulling the particles deeper into the atmosphere in a shower of methane snow. Because Neptune has a more active, turbulent atmosphere than Uranus does, the team believes Neptune's atmosphere is more efficient at churning up methane particles into the haze layer and producing this snow. This removes more of the haze and keeps Neptune's haze layer thinner than it is on Uranus, meaning the blue colour of Neptune looks stronger. To create this model, the team analysed a set of observations of the planets encompassing ultraviolet, visible, and near-infrared wavelengths (from 0.3 to 2.5 micrometres) taken with the Near-Infrared Integral Field Spectrometer (NIFS) on the Gemini North telescope near the summit of Maunakea in Hawai'i -- which is part of the international Gemini Observatory, a Program of NSF's NOIRLab -- as well as archival data from the NASA Infrared Telescope Facility, also located in Hawai'i, and the NASA/ESA Hubble Space Telescope. The NIFS instrument on Gemini North was particularly important to this result as it is able to provide spectra -- measurements of how bright an object is at different wavelengths -- for every point in its field of view. This provided the team with detailed measurements of how reflective both planets' atmospheres are across both the full disk of the planet and across a range of near-infrared wavelengths. The model also helps explain the dark spots that are occasionally visible on Neptune and less commonly detected on Uranus. While astronomers were already aware of the presence of dark spots in the atmospheres of both planets, they didn't know which aerosol layer was causing these dark spots or why the aerosols at those layers were less reflective. The team's research sheds light on these questions by showing that a darkening of the deepest layer of their model would produce dark spots similar to those seen on Neptune and perhaps Uranus.
PLANETS OF BINARY STARS MIGHT SUPPORT LIFE FORMS
University of Copenhagen - Faculty of Science
Nearly half of Sun-size stars are binary. According to University of Copenhagen research, planetary systems around binary stars may be very different from those around single stars. This points to new targets in the search for extraterrestrial life forms. Since the only known planet with life, the Earth, orbits the Sun, planetary systems around stars of similar size are obvious targets for astronomers trying to locate extraterrestrial life. Nearly every second star in that category is a binary star. New research indicates that planetary systems are formed in a very different way around binary stars than around single stars such as the Sun. The new discovery has been made based on observations made by the ALMA telescopes in Chile of a young binary star about 1,000 lightyears from Earth. The binary star system, NGC 1333-IRAS2A, is surrounded by a disc consisting of gas and dust. The observations can only provide researchers with a snapshot from a point in the evolution of the binary star system. However, the team has complemented the observations with computer simulations reaching both backwards and forwards in time. Notably, the movement of gas and dust does not follow a continuous pattern. At some points in time -- typically for relatively shorts periods of ten to one hundred years every thousand years -- the movement becomes very strong. The binary star becomes ten to one hundred times brighter, until it returns to its regular state. Presumably, the cyclic pattern can be explained by the duality of the binary star. The two stars encircle each other, and at given intervals their joint gravity will affect the surrounding gas and dust disc in a way which causes huge amounts of material to fall towards the star. The observed stellar system is still too young for planets to have formed. The team hopes to obtain more observational time at ALMA, allowing to investigate the formation of
Very soon the new James Webb Space Telescope (JWST) will join the search for extraterrestrial life. Near the end of the decade, JWST will be complemented by the ELT (European Large Telescope) and the extremely powerful SKA (Square Kilometer Array) both planned to begin observing in 2027. The ELT will with its 39-meter mirror be the biggest optical telescope in the world and will be poised to observe the atmospheric conditions of exoplanets (planets outside the Solar System, ed.). SKA will consist of thousands of telescopes in South Africa and in Australia working in coordination and will have longer wavelengths than ALMA. The team has had observation time on the ALMA telescopes in Chile to observe the binary star system NGC 1333-IRAS2A in the Perseus molecular cloud. The distance from Earth to the binary star is about 1,000 lightyears which is a quite short distance in an astronomical context. Formed some 10,000 years ago, it is a very young star. The two stars of the binary system are 200 astronomical units (AUs) apart. An AU equals the distance from Earth to the Sun. In comparison, the furthest planet of the Solar System, Neptune, is 30 AUs from the Sun.

JAMES WEBB TARGETS ANNOUNCED
NASA

Over the past five months, the James Webb Space Telescope and the joint NASA, European Space Agency, and Canadian Space Agency teams behind the project have been working towards the completion of the observatory's six-month-long commissioning phase at the Sun-Earth Lagrange point 2 (L2). With the observatory's mirrors recently completing alignment, Webb and its teams are preparing for the all-important and historic first image from the observatory. As teams continue to work towards completing commissioning, some of the first scientific research targets of Webb's operational phase have been announced, including two strange and intriguing exoplanets that exhibit unique characteristics. After confirming that all of the optical and structural systems are operating as planned, James Webb's commissioning phase will be complete and the observatory will assume operational status. Webb and its science teams have already lined up a plethora of research targets for the first few weeks of the observatory's operational phase, some of which may produce images as we've never seen before from other telescopes. Among the many research targets outlined for Webb's first few weeks of operation are two exoplanets that exhibit unique characteristics: 55 Cancri e and LHS 3844 b. 55 Cancri e is an extremely hot super-Earth exoplanet located 41 light-years away in the constellation Cancer, where it orbits its Sun-like parent star 55 Cancri A. The exoplanet is around double the diameter of Earth and is around 8.63 Earth masses. At the time of its discovery in August 2004, it was the first super-Earth to be found. Orbiting just 1.5 million miles from 55 Cancri A, the exoplanet completes one orbit around its parent star in just 18 hours and is thought to feature oceans of lava on its dayside due to its extremely hot surface temperatures. What's more, 55 Cancri e is likely tidally locked due to its close proximity to 55 Cancri A. This would be expected to ensure that the parts of the surface facing the star most directly would be the hottest region of the planet. Telescope data from NASA's Spitzer Space Telescope, however, suggests otherwise - showing that the exoplanet's hottest region is offset from this position. Spitzer data also indicates that the total amount of heat on the dayside of the planet varies.
One of the leading theories behind the Spitzer observations is that 55 Cancri e may have a thick and dynamic atmosphere that moves heat around the planet from various regions. Another theory behind the occurrence could be that 55 Cancri e isn't actually tidally locked, and is instead more like Mercury: orbiting on its axis three times for every two orbits it completes around 55 Cancri A in what is called a 3:2 resonance. The 3:2 resonance scenario would cause 55 Cancri e's surface to heat up, melt, and vaporise into the exoplanet's atmosphere. When the vapour eventually cools in the evening, it could condense and form droplets of lava that would subsequently rain onto the exoplanet's surface. To truly determine the cause of 55 Cancri e's heat distribution, Webb teams will use the observatory's Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI) in different ways to test each theory. When testing the first theory involving a thick atmosphere, teams will use NIRCam and MIRI to view the thermal emission spectrum from the dayside. To test the second theory wherein the exoplanet isn't tidally locked, teams will use NIRCam to observe and measure the heat emitted from the dayside over four orbits, allowing teams to measure each hemisphere of the exoplanet twice if the exoplanet truly has a 3:2 resonance. This allows teams to observe whether there are any differences between the planet's two hemispheres.
Another research target for Webb is another extremely hot super-Earth exoplanet named LHS 3844 b. Located 49 light-years away orbiting red dwarf LHS 3488, LHS 3488 b - like 55 Cancri e - orbits extremely close to its parent star, completing one orbit around it in just 11 hours. LHS 3488 b's parent star is a red dwarf, meaning it is much cooler and smaller than Sun-like stars such as 55 Cancri A. Due to its parent star's small size, LHS 3488 b is not hot enough to have a molten surface like 55 Cancri e and Spitzer data suggests it likely does not have an atmosphere surrounding it. The lack of an atmosphere around LHS 3488 b gives scientists the chance to carry out a thorough examination of possible rock formations and other surface characteristics using telescopes. Although Webb is not capable of imaging the exoplanet's surface directly, teams can use spectroscopy to study it. Webb's observations of 55 Cancri e and LHS 3488 b are part of the observatory's Cycle 1 General Observer program. Under the General Observers program, scientists can submit research targets for Webb to observe for their research. This same process is also used with the Hubble telescope to allocate time for scientists.

HIDDEN TROVE OF MASSIVE BLACK HOLES
University of North Carolina at Chapel Hill

A team of researchers has found a previously overlooked treasure trove of massive black holes in dwarf galaxies. The newly discovered black holes offer a glimpse into the life story of the supermassive black hole at the centre of our own Milky Way galaxy. As a giant spiral galaxy, the Milky Way is believed to have been built up from mergers of many smaller dwarf galaxies. For example, the Magellanic Clouds seen in the southern sky are dwarf galaxies that will merge into the Milky Way. Each dwarf that falls in may bring with it a central massive black hole, tens or hundreds of thousands of times the mass of our Sun, potentially destined to be swallowed by the Milky Way's central supermassive black hole. But how often dwarf galaxies contain a massive black hole is unknown, leaving a key gap in our understanding of how black holes and galaxies grow together. New research helps to fill in this gap by revealing that massive black holes are many times more common in dwarf galaxies than previously thought. Black holes are typically detected when they are actively growing by ingesting gas and stardust swirling around them, which makes them glow intensely. The problem is, while growing black holes glow with distinctive high-energy radiation, young newborn stars can too. Traditionally, astronomers have differentiated growing black holes from new star formation using diagnostic tests that rely on detailed features of each galaxy's visible light when spread out into a spectrum like a rainbow. The path to discovery began when researchers tried to apply these traditional tests to galaxy survey data. The team realized that some of the galaxies were sending mixed messages -- two tests would indicate growing black holes, but a third would indicate only star formation.
Scientists took on the challenge of constructing a new census of growing black holes, with attention to both traditional and mixed-message types. They obtained published measurements of visible light spectral features to test for black holes in thousands of galaxies found in two surveys, RESOLVE and ECO. These surveys include ultraviolet and radio data ideal for studying star formation, and they have an unusual design: Whereas most astronomical surveys select samples that favor big and bright galaxies, RESOLVE and ECO are complete inventories of huge volumes of the present-day universe in which dwarf galaxies are abundant. More than 80 percent of all growing black holes found in dwarf galaxies belonged to the new type. The group led an exhaustive search for alternative explanations involving star formation, modelling uncertainties, or exotic astrophysics. In the end, the team was forced to conclude that the newly identified black holes were real.

STARS IN DISTANT GALAXIES MORE MASSIVE THAN EXPECTED
University of Copenhagen - Faculty of Science

Astrophysicists have arrived at a major result regarding star populations beyond the Milky Way. The result could change our understanding of a wide range of astronomical phenomena, including the formation of black holes, supernovae and why galaxies die. Since 1955, it has been assumed that the composition of stars in the Universe's other galaxies is similar to that of the hundreds of billions of stars within our own -- a mixture of massive, medium mass and low mass stars. But with the help of observations from 140,000 galaxies across the Universe and a wide range of advanced models, the team has tested whether the same distribution of stars apparent in the Milky Way applies elsewhere. The answer is no. Stars in distant galaxies are typically more massive than those in our "local neighbourhood." The finding has a major impact on what we think we know about the Universe. The mass of stars tells astronomers a lot. If you change mass, you also change the number of supernovae and black holes that arise out of massive stars. As such, this result means that we'll have to revise many of the things we once presumed, because distant galaxies look quite different from our own. Researchers assumed that the size and weight of stars in other galaxies was similar to our own for more than fifty years, for the simple reason that they were unable to observe them through a telescope, as they could with the stars of our own galaxy. Distant galaxies are billions of light-years away.
As a result, only light from their most powerful stars ever reaches Earth. This has been a headache for researchers around the world for years, as they could never accurately clarify how stars in other galaxies were distributed, an uncertainty that forced them to believe that they were distributed much like the stars in our Milky Way. We've only been able to see the tip of the iceberg and known for a long time that expecting other galaxies to look like our own was not a particularly good assumption to make. However, no one has ever been able to prove that other galaxies form different populations of stars. This study has allowed us to do just that, which may open the door for a deeper understanding of galaxy formation and evolution. In the study, the researchers analyzed light from 140,000 galaxies using the COSMOS catalogue, a large international database of more than one million observations of light from other galaxies. These galaxies are distributed from the nearest to farthest reaches of the Universe, from which light has travelled a full twelve billion years before being observable on Earth.

'COSMIC TELESCOPE' STUDIES HEART OF YOUNG UNIVERSE
North Carolina State University

A unique new instrument, coupled with a powerful telescope and a little help from nature, has given researchers the ability to peer into galactic nurseries at the heart of the young Universe. After the big bang some 13.8 billion years ago, the early Universe was filled with enormous clouds of neutral diffuse gas, known as Damped Lyman-α systems, or DLAs. These DLAs served as galactic nurseries, as the gasses within slowly condensed to fuel the formation of stars and galaxies. They can still be observed today, but it isn't easy. Currently, astrophysicists use quasars -- supermassive black holes that emit light -- as "backlight" to detect the DLA clouds. And while this method does allow researchers to pinpoint DLA locations, the light from the quasars only acts as small skewers through a massive cloud, hampering efforts to measure their total size and mass. But astronomers at the W.M. Keck Observatory in Hawaii, found a way around the problem by using a gravitationally lensed galaxy and integral field spectroscopy to observe two DLAs -- and the host galaxies within -- that formed around 11 billion years ago, not long after the big bang. The advantage to this is twofold: One, the background object is extended across the sky and bright, so it is easy to take spectrum readings on different parts of the object. Two, because lensing extends the object, you can probe very small scales. For example, if the object is one light year across, we can study small bits in very high fidelity.
Spectrum readings allow astrophysicists to "see" elements in deep space that are not visible to the naked eye, such as diffuse gaseous DLAs and the potential galaxies within them. Normally, gathering the readings is a long and painstaking process. But the team solved that issue by performing integral field spectroscopy with the Keck Cosmic Web Imager. Integral field spectroscopy allowed the researchers to obtain a spectrum at every single pixel on the part of the sky it targeted, making spectroscopy of an extended object on the sky very efficient. This innovation combined with the stretched and brightened gravitationally lensed galaxy allowed the team to map out the diffuse DLA gas in the sky at high fidelity. Through this method the researchers were able to determine not only the size of the two DLAs, but also that they both contained host galaxies. The DLAs are huge, by the way. With diameters greater than 17.4 kiloparsecs, they're more than two thirds the size of the Milky Way galaxy today. For comparison, 13 billion years ago, a typical galaxy would have a diameter of less than 5 kiloparsecs. A parsec is 3.26 light years, and a kiloparsec is 1,000 parsecs, so it would take light about 56,723 years to travel across each DLA.
NEW MILESTONE IN UNIVERSE'S EXPANSION RATE
NASA/Goddard
Completing a nearly 30-year marathon, NASA's Hubble Space Telescope has calibrated more than 40 "milepost markers" of space and time to help scientists precisely measure the expansion rate of the Universe -- a quest with a plot twist. Pursuit of the Universe's expansion rate began in the 1920s with measurements by astronomers Edwin P. Hubble and Georges Lemaître. In 1998, this led to the discovery of "dark energy," a mysterious repulsive force accelerating the universe's expansion. In recent years, thanks to data from Hubble and other telescopes, astronomers found another twist: a discrepancy between the expansion rate as measured in the local universe compared to independent observations from right after the big bang, which predict a different expansion value. The cause of this discrepancy remains a mystery. But Hubble data, encompassing a variety of cosmic objects that serve as distance markers, support the idea that something weird is going on, possibly involving brand new physics. The new results more than double the prior sample of cosmic distance markers. The team also reanalyzed all of the prior data, with the whole dataset now including over 1,000 Hubble orbits. When NASA conceived of a large space telescope in the 1970s, one of the primary justifications for the expense and extraordinary technical effort was to be able to resolve Cepheids, stars that brighten and dim periodically, seen inside our Milky Way and external galaxies. Cepheids have long been the gold standard of cosmic mile markers since their utility was discovered by astronomer Henrietta Swan Leavitt in 1912. To calculate much greater distances, astronomers use exploding stars called Type Ia supernovae. Combined, these objects built a "cosmic distance ladder" across the universe and are essential to measuring the expansion rate of the universe, called the Hubble constant after Edwin Hubble. That value is critical to estimating the age of the universe and provides a basic test of our understanding of the Universe. Starting right after Hubble's launch in 1990, the first set of observations of Cepheid stars to refine the Hubble constant was undertaken by the HST Key Project that used Cepheids as milepost markers to refine the distance measurement to nearby galaxies. By the early 2000s the teams declared "mission accomplished" by reaching an accuracy of 10 percent for the Hubble constant, 72 plus or minus 8 kilometres per second per megaparsec.
In 2005 and again in 2009, the addition of powerful new cameras onboard the Hubble telescope launched "Generation 2" of the Hubble constant research as teams set out to refine the value to an accuracy of just one percent. This was inaugurated by the SH0ES program. Several teams of astronomers using Hubble, including SH0ES, have converged on a Hubble constant value of 73 plus or minus 1 kilometre per second per megaparsec. While other approaches have been used to investigate the Hubble constant question, different teams have come up with values close to the same number. The team measured 42 of the supernova milepost markers with Hubble. Because they are seen exploding at a rate of about one per year, Hubble has, for all practical purposes, logged as many supernovae as possible for measuring the Universe's expansion. The expansion rate of the Universe was predicted to be slower than what Hubble actually sees. By combining the Standard Cosmological Model of the Universe and measurements by the European Space Agency's Planck mission (which observed the relic cosmic microwave background from 13.8 billion years ago), astronomers predict a lower value for the Hubble constant: 67.5 plus or minus 0.5 kilometres per second per megaparsec, compared to the SH0ES team's estimate of 73. Given the large Hubble sample size, there is only a one-in-a-million chance astronomers are wrong due to an unlucky draw -a common threshold for taking a problem seriously in physics. This finding is untangling what was becoming a nice and tidy picture of the universe's dynamical evolution. Astronomers are at a loss for an explanation of the disconnect between the expansion rate of the local Universe versus the primeval Universe, but the answer might involve additional physics of the Universe. Such confounding findings have made life more exciting for cosmologists. Thirty years ago they started out to measure the Hubble constant to benchmark the Universe, but now it has become something even more interesting.
Bulletin compiled by Clive Down
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Astronomy / The Night sky on June
June 02, 2022, 11:25:02 am
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THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 566 2022 May 22

We're delighted that the Society for Popular Astronomy's free Electronic News Bulletins have gained many hundreds of subscribers since we first issued them more than 23 years ago!

They remain free, but if you are not already a member of the SPA, we hope you will consider joining, and supporting the UK's liveliest astronomical society, with members worldwide. You can easily sign up online. https://www.popastro.com/main_...

And now, here is our latest round-up of news.

LUNAR SOIL MIGHT GENERATE OXYGEN AND FUEL
Cell Press

Soil on the Moon contains active compounds that can convert carbon dioxide into oxygen and fuels, scientists in China report. They are now exploring whether lunar resources can be used to facilitate human exploration on the Moon or beyond. Nanjing University material scientists hope to design a system that takes advantage of lunar soil and solar radiation, the two most abundant resources on the Moon. After analyzing the lunar soil brought back by China's Chang'e 5 spacecraft, their team found the sample contains compounds -- including iron-rich and titanium-rich substances -- that could work as a catalyst to make desired products such as oxygen using sunlight and carbon dioxide. Based on the observation, the team proposed an "extraterrestrial photosynthesis" strategy. Mainly, the system uses lunar soil to electrolyze water extracted from the moon and in astronauts' breathing exhaust into oxygen and hydrogen powered by sunlight. The carbon dioxide exhaled by moon inhabitants is also collected and combined with hydrogen from water electrolysis during a hydrogenation process catalyzed by lunar soil. The process yields hydrocarbons such as methane, which could be used as fuel. The strategy uses no external energy but sunlight to produce a variety of desirable products such as water, oxygen, and fuel that could support life on a moonbase, the researchers say. The team is looking for an opportunity to test the system in space, likely with China's future crewed lunar missions.

While the catalytic efficiency of lunar soil is less than catalysts available on Earth, the team is testing different approaches to improve the design, such as melting the lunar soil into a nanostructured high-entropy material, which is a better catalyst. Previously, scientists have proposed many strategies for extraterrestrial survival. But most designs require energy sources from Earth. For example, NASA's Perseverance Mars rover brought an instrument that can use carbon dioxide in the planet's atmosphere to make oxygen, but it's powered by a nuclear battery onboard. In the near future, China claims we will see the crewed spaceflight industry developing rapidly. Just like the 'Age of Sail' in the 1600s when hundreds of ships head to the sea, we will enter an 'Age of Space.' But if we want to carry out large-scale exploration of the extraterrestrial world, we will need to think of ways to reduce payload, meaning relying on as little supplies from Earth as possible and using extraterrestrial resources instead.

LIMITED WATER CIRCULATION LATE IN MARTIAN HISTORY
Lund University
A Swedish research team has investigated a meteorite from Mars using neutron and X-ray tomography. The technology, which will probably be used when NASA examines samples from the Red Planet in 2030, showed that the meteorite had limited exposure to water, thus making life at that specific time and place unlikely. In a cloud of smoke, NASA's spacecraft Perseverance parachuted onto the dusty surface of Mars in February 2021. For several years, the vehicle will skid around and take samples to try to answer the question posed by David Bowie in Life on Mars in 1971. It isn't until around 2030 that Nasa actually intends to send the samples back to Earth, but material from Mars is already being studied -- in the form of meteorites. In a new study published in Science Advances, an international research team has studied an approximately 1.3 billion-year-old meteorite using advanced scanning. Since water is central to the question of whether life ever existed on Mars, researchers wanted to investigate how much of the meteorite reacted with water when it was still part of the Mars bedrock. To answer the question of whether there was any major hydrothermal system, which is generally a favourable environment for life to occur, the researchers used neutron and X-ray tomography. X-ray tomography is a common method of examining an object without damaging it. Neutron tomography was used because neutrons are very sensitive to hydrogen. This means that if a mineral contains hydrogen, it is possible to study it in three dimensions and see where in the meteorite the hydrogen is located. Hydrogen (H) is always of interest when scientists study material from Mars, because water (H2O) is a prerequisite for life as we know it. The results show that a fairly small part of the sample seems to have reacted with water, and that it therefore probably wasn't a large hydrothermal system that gave rise to the alteration.

A more probable explanation is that the reaction took place after small accumulations of underground ice melted during a meteorite impact about 630 million years ago. Of course, that doesn't mean that life couldn't have existed in other places on Mars, or that there couldn't have been life at other times. The researchers hope that the results of their study will be helpful when NASA brings back the first samples from Mars around 2030, and there are many reasons to believe that the current technology with neutron and X-ray tomography will be useful when this happens.

LARGEST MARTIAN EARTHQUAKE DETECTED
NASA

NASA's InSight Mars lander has detected the largest quake ever observed on another planet: an estimated magnitude 5 temblor that occurred on May 4, 2022, the 1,222nd Martian day, or sol, of the mission. This adds to the catalogue of more than 1,313 quakes InSight has detected since landing on Mars in November 2018. The largest previously recorded quake was an estimated magnitude 4.2 detected Aug. 25, 2021. InSight was sent to Mars with a highly sensitive seismometer to study the deep interior of the planet. As seismic waves pass through or reflect off material in Mars' crust, mantle, and core, they change in ways that seismologists can study to determine the depth and composition of these layers. What scientists learn about the structure of Mars can help them better understand the formation of all rocky worlds, including Earth and its Moon.

A magnitude 5 quake is a medium-size quake compared to those felt on Earth, but it's close to the upper limit of what scientists hoped to see on Mars during InSight's mission. The science team will need to study this new quake further before being able to provide details such as its location, the nature of its source, and what it might tell us about the interior of Mars. The large quake comes as InSight is facing new challenges with its solar panels, which power the mission. As InSight's location on Mars enters winter, there's more dust in the air, reducing available sunlight. On May 7, 2022, the lander's available energy fell just below the limit that triggers safe mode, where the spacecraft suspends all but the most essential functions. This reaction is designed to protect the lander and may occur again as available power slowly decreases. After the lander completed its prime mission at the end of 2020, meeting its original science goals, NASA extended the mission until December 2022.

MILKY WAY STAR CONTAINS 65 ELEMENTS OF PERIODIC TABLE
University of Michigan

In our Sun's neighbourhood of the Milky Way Galaxy is a relatively bright star, and in it, astronomers have been able to identify the widest range of elements in a star beyond our solar system yet. The study has identified 65 elements in the star, HD 222925. Forty-two of the elements identified are heavy elements that are listed along the bottom of the periodic table of elements. Identifying these elements in a single star will help astronomers understand what's called the "rapid neutron capture process," or one of the major ways by which heavy elements in the Universe were created. The process, also called the "r-process," begins with the presence of lighter elements such as iron. Then, rapidly -- on the order of a second -- neutrons are added to the nuclei of the lighter elements. This creates heavier elements such as selenium, silver, tellurium, platinum, gold and thorium, the kind found in HD 222925, and all of which are rarely detected in stars, according to the astronomers.  One of these environments has been confirmed: the merging of neutron stars. Neutron stars are the collapsed cores of supergiant stars, and are the smallest and densest known celestial objects. The collision of neutron star pairs causes gravitational waves and in 2017, astronomers first detected gravitational waves from merging neutron stars. Another way the r-process might occur is after the explosive death of massive stars. The elements the team identified in HD 222925 were produced in either a massive supernovae or a merger of neutron stars very early in the Universe. The material was ejected and thrown back into space, where it later reformed into the star HD 222925.

This star can then be used as a proxy for what one of those events would have produced. Any model developed in the future that demonstrates how the r-process or nature produces elements on the bottom two-thirds of the periodic table must have the same signature as HD 222925. Crucially, the astronomers used an instrument on the Hubble Space Telescope that can collect ultraviolet spectra. This instrument was key in allowing the astronomers to collect light in the ultraviolet part of the light spectrum -- light that is faint, coming from a cool star such as HD 222925. The astronomers also used one of the Magellan telescopes in Chile to collect light from HD 222925 in the optical part of the light spectrum. These spectra encode the "chemical fingerprint" of elements within stars, and reading these spectra allows the astronomers not only to identify the elements contained in the star, but also how much of an element the star contains. Many of the study co-authors are part of a group called the R-Process Alliance, a group of astrophysicists dedicated to solving the big questions of the r-process. This project marks one of the team's key goals: identifying which elements, and in what amounts, were produced in the r-process in an unprecedented level of detail.

EGYPTIAN STONE BRINGS FIRST SUPERNOVA CLUES TO EARTH
University of Johannesburg

New chemistry 'forensics' indicate that the stone named Hypatia from the Egyptian desert could be the first tangible evidence found on Earth of a supernova type Ia explosion. These rare supernovae are some of the most energetic events in the Universe. Since 2013, researchers have discovered a series of highly unusual chemistry clues in a small fragment of the Hypatia Stone. In the new research, they eliminate 'cosmic suspects' for the origin of the stone in a painstaking process. They have pieced together a timeline stretching back to the early stages of the formation of Earth, our Sun and the other planets in our solar system. Their hypothesis about Hypatia's origin starts with a star: A red giant star collapsed into a white dwarf star. The collapse would have happened inside a gigantic nebula. That white dwarf found itself in a binary system with a second star. The white dwarf star eventually 'ate' the other star. At some point the white dwarf exploded as a supernova type Ia inside the dust cloud. After cooling, the gas atoms which remained of the supernova Ia started sticking to the particles of the dust cloud. A huge 'bubble' of this supernova dust-and-gas-atoms mix never interacted with other dust clouds. Millions of years would pass, and eventually the 'bubble' would slowly become solid. Hypatia's 'parent body' would become a solid rock sometime in the early stages of formation of our solar system. This process probably happened in a cold, uneventful outer part of our solar system -- in the Oort cloud or in the Kuiper belt. At some point, Hypatia's parent rock started hurtling towards Earth. The heat of entry into Earth's atmosphere, combined with the pressure of impact in the Great Sand Sea in south-western Egypt, created micro-diamonds and shattered the parent rock. The Hypatia stone picked up in the desert must be one of many fragments of the original impactor. If this hypothesis is correct, the Hypatia stone would be the first tangible evidence on Earth of a supernova type Ia explosion. Perhaps equally important, it shows that an individual anomalous 'parcel' of dust from outer space could actually be incorporated in the solar nebula that our solar system was formed from, without being fully mixed in. This goes against the conventional view that dust which our solar system was formed from, was thoroughly mixed.

To piece together the timeline of how Hypatia may have formed, the researchers used several techniques to analyse the strange stone. In 2013, a study of the argon isotopes showed the rock was not formed on Earth. It had to be extraterrestrial. A 2015 study of noble gases in the fragment indicated that it may not be from any known type of meteorite or comet. In 2018 the UJ team published various analyses, which included the discovery of a mineral, nickel phosphide, not previously found in any object in our solar system. The team selected 17 targets on the tiny sample for analysis. All were chosen to be well away from the earthly minerals that had formed in the cracks of the original rock after its impact in the desert. 15 different elements were identified in Hypatia with much greater precision and accuracy, with the proton microprobe. This gave the chemical 'ingredients' needed to start the next process of analysing all the data. The first big new clue from the proton beam analyses was the surprisingly low level of silicon in the Hypatia stone targets. The silicon, along with chromium and manganese, were less than 1% to be expected for something formed within our inner solar system. Further, high iron, high sulphur, high phosphorus, high copper and high vanadium were conspicuous and anomalous. A consistent pattern was found of trace element abundances that is completely different from anything in the solar system, primitive or evolved. Objects in the asteroid belt and meteors don't match this either. So next researchers looked outside the solar system and compared the Hypatia element concentration pattern with what one would expect to see in the dust between stars in our solar arm of the Milky Way galaxy. There was no similarity at all. The next simplest possible explanation for the element concentration pattern in Hypatia, would be a red giant star. Red giant stars are common in the Universe. But the proton beam data ruled out mass outflow from a red giant star too: Hypatia had too much iron, too little silicon and too low concentrations of heavy elements heavier than iron.

The next 'suspect' to consider was a supernova type II. Supernovae of type II cook up a lot of iron. They are also a relatively common type of supernova. Again, the proton beam data for Hypatia ruled out a promising suspect with 'chemistry forensics'. A supernova type II was highly unlikely as the source of strange minerals like nickel phosphide in the pebble. There was also too much iron in Hypatia compared to silicon and calcium. It was time to closely examine the predicted chemistry of one of the most dramatic explosions in the Universe. A rarer kind of supernova also makes a lot of iron. Supernovas of the type Ia only happen once or twice per galaxy per century. But they manufacture most of the iron (Fe) in the Universe. Also, established science says that some Ia supernovas leave very distinctive 'forensic chemistry' clues behind. This is because of the way some Ia supernovas are set up. First, a red giant star at the end of its life collapses into a very dense white dwarf star. White dwarf stars are usually incredibly stable for very long periods and most unlikely to explode. However, there are exceptions to this. A white dwarf star could start 'pulling' matter off another star in a binary system. Eventually the white dwarf gets so heavy, hot and unstable, it explodes in a supernova Ia. The nuclear fusion during the supernova Ia explosion should create highly unusual element concentration patterns, accepted scientific theoretical models predict. Also, the white dwarf star that explodes in a supernova Ia is not just blown to bits, but literally blown to atoms. The supernova Ia matter is delivered into space as gas atoms. In an extensive literature search of star data and model results, the team could not identify any similar or better chemical fit for the Hypatia stone than a specific set of supernova Ia models. Not all 15 of the analysed elements in Hypatia fit the predictions though. In six of the 15 elements, proportions were between 10 and 100 times higher than the ranges predicted by theoretical models for supernovas of type 1A. These are the elements aluminium, phosphorus, chlorine, potassium, copper and zinc. If this hypothesis is correct, the Hypatia stone would be the first tangible evidence on Earth of a supernova type Ia explosion, one of the most energetic events in the Universe.

EXPLOSION OBSERVED ON WHITE DWARF
Friedrich-Alexander-Universität Erlangen-Nürnberg

When stars like our Sun use up all their fuel, they shrink to form white dwarfs. Sometimes such dead stars flare back to life in a super hot explosion and produce a fireball of X-ray radiation. A research team has now been able to observe such an explosion of X-ray light for the very first time. These X-ray flashes last only a few hours and are almost impossible to predict, but the observational instrument must be pointed directly at the explosion at exactly the right time. The instrument in this case is the eROSITA X-ray telescope, which is currently located one and a half million kilometres from Earth and has been surveying the sky for soft X-rays since 2019. On July 7, 2020 it measured strong X-ray radiation in an area of the sky that had been completely inconspicuous four hours previously. When the X-ray telescope surveyed the same position in the sky four hours later, the radiation had disappeared. It follows that the X-ray flash that had previously completely overexposed the centre of the detector must have lasted less than eight hours. X-ray explosions such as this were predicted by theoretical research more than 30 years ago, but have never been observed directly until now. These fireballs of X-rays occur on the surface of stars that were originally comparable in size to the Sun before using up most of their fuel made of hydrogen and later helium deep inside their cores. These stellar corpses shrink until "white dwarfs" remain, which are similar to Earth in size but contain a mass that can be similar to that of our Sun. One way to picture these proportions is to think of the Sun being the same size as an apple, which means Earth would be the same size as a pin head orbiting around the apple at a distance of 10 metres. On the other hand, if you were to shrink an apple to the size of a pin head, this tiny particle would retain the comparatively large weight of the apple. A teaspoon of matter from the inside of a white dwarf easily has the same mass as a large truck. Since these burned out stars are mainly made up of oxygen and carbon, we can compare them to gigantic diamonds that are the same size as Earth floating around in space. These objects in the form of precious gems are so hot they glow white. However, the radiation is so weak that it is difficult to detect from Earth.

Unless the white dwarf is accompanied by a star that is still burning, that is, and when the enormous gravitational pull of the white dwarf draws hydrogen from the shell of the accompanying star. "In time, this hydrogen can collect to form a layer only a few metres thick on the surface of the white dwarf. In this layer, the huge gravitational pull generates enormous pressure that is so great that it causes the star to reignite. In a chain reaction, it soon comes to a huge explosion during which the layer of hydrogen is blown off. The X-ray radiation of an explosion like this is what hit the detectors of eROSITA on July 7, 2020 producing an overexposed image. Using the model calculations the team originally drew up while supporting the development of the X-ray instrument, researchers were able to analyze the overexposed image in more detail during a complex process to gain a behind the scenes view of an explosion of a white dwarf, or nova. According to the results, the white dwarf has around the mass of our Sun and is therefore relatively large. The explosion generated a fireball with a temperature of around 327,000 degrees, making it around sixty times hotter than the Sun. Since these novae run out of fuel quite quickly, they cool rapidly and the X-ray radiation becomes weaker until it eventually becomes visible light, which reached Earth half a day after the eROSITA detection and was observed by optical telescopes. A seemingly bright star then appeared, which was actually the visible light from the explosion, and so bright that it could be seen on the night sky by the naked eye. Seemingly "new stars" such as this one have been observed in the past and were named "nova stella," or "new star" on account of their unexpected appearance. Since these novae are only visible after the X-ray flash, it is very difficult to predict such outbreaks and it is mainly down to chance when they hit the X-ray detectors.

SURVIVING COMPANION IN SUPERNOVA AFTERMATH REVEALED
NASA/Goddard Space Flight Center

It's not unheard of to find a surviving star at the scene of a titanic supernova explosion, which would be expected to obliterate everything around it, but the latest research from the Hubble Space Telescope has provided a long-awaited clue to a specific type of stellar death. In some supernova cases, astronomers find no trace of the former star's outermost layer of hydrogen. What happened to the hydrogen? Suspicions that companion stars are responsible -- siphoning away their partners' outer shell before their death -- are supported by Hubble's identification of a surviving companion star on the scene of supernova 2013ge. The discovery also lends support to the theory that the majority of massive stars form and evolve as binary systems. It could also be the prequel to another cosmic drama: In time, the surviving, massive companion star will also undergo a supernova, and if both the stars' remnant cores are not flung from the system, they will eventually merge and produce gravitational waves, shaking the fabric of space itself. NASA's Hubble Space Telescope has uncovered a witness at the scene of a star's explosive death: a companion star previously hidden in the glare of its partner's supernova. The discovery is a first for a particular type of supernova -- one in which the star was stripped of its entire outer gas envelope before exploding. The finding provides crucial insight into the binary nature of massive stars, as well as the potential prequel to the ultimate merger of the companion stars that would rattle across the Universe as gravitational waves, ripples in the fabric of spacetime itself.

Astronomers detect the signature of various elements in supernova explosions. These elements are layered like an onion pre-supernova. Hydrogen is found in the outermost layer of a star, and if no hydrogen is detected in the aftermath of the supernova, that means it was stripped away before the explosion occurred. The cause of the hydrogen loss had been a mystery, and astronomers have been using Hubble to search for clues and test theories to explain these stripped supernovae. The new Hubble observations provide the best evidence yet to support the theory that an unseen companion star siphons off the gas envelope from its partner star before it explodes. Astronomers used Hubble's Wide Field Camera 3 to study the region of supernova (SN) 2013ge in ultraviolet light, as well as previous Hubble observations in the Barbara A. Mikulski Archive for Space Telescopes. Astronomers saw the light of the supernova fading over time from 2016 to 2020 -- but another nearby source of ultraviolet light at the same position maintained its brightness. This underlying source of ultraviolet emission is what the team proposes is the surviving binary companion to SN 2013ge. Previously, scientists theorized that a massive progenitor star's strong winds could blow away its hydrogen gas envelope, but observational evidence didn't support that. To explain the disconnect, astronomers developed theories and models in which a binary companion siphons off the hydrogen. In prior observations of SN 2013ge, Hubble saw two peaks in the ultraviolet light, rather than just the one typically seen in most supernovae. One explanation for this double brightening was that the second peak shows when the supernova's shock wave hit a companion star, a possibility that now seems much more likely. Hubble's latest observations indicate that while the companion star was significantly jostled, including the hydrogen gas it had siphoned off its partner, it was not destroyed. Researchers liken the effect to a jiggling bowl of jelly, which will eventually settle back to its original form. While additional confirmation and similar supporting discoveries need to be found, the implications of the discovery are still substantial, lending support to theories that the majority of massive stars form and evolve as binary systems.

Unlike supernovae that have a puffy shell of gas to light up, the progenitors of fully stripped-envelope supernovae have proven difficult to identify in pre-explosion images. Now that astronomers have been lucky enough to identify the surviving companion star, they can use it to work backward and determine characteristics of the star that exploded, as well as the unprecedented opportunity to watch the aftermath unfold with the survivor. As a massive star itself, SN 2013ge's companion is also destined to undergo a supernova. Its former partner is now likely a compact object, such as a neutron star or black hole, and the companion will likely go that route as well. The closeness of the original companion stars will determine if they stay together. If the distance is too great, the companion star will be flung out of the system to wander alone across our galaxy, a fate that could explain many seemingly solitary supernovae. However, if the stars were close enough to each other pre-supernova, they will continue orbiting each other as black holes or neutron stars. In that case, they would eventually spiral toward each other and merge, creating gravitational waves in the process. That is an exciting prospect for astronomers, as gravitational waves are a branch of astrophysics that has only begun to be explored. They are waves or ripples in the fabric of spacetime itself, predicted by Albert Einstein in the early 20th century. Gravitational waves were first directly observed by the Laser Interferometer Gravitational-Wave Observatory.

FIRST IMAGE TAKEN OF BLACK HOLE AT CENTRE OF MILKY WAY
ESO

Astronomers have unveiled the first image of the supermassive black hole at the centre of our own Milky Way galaxy. This result provides overwhelming evidence that the object is indeed a black hole and yields valuable clues about the workings of such giants, which are thought to reside at the centre of most galaxies. The image was produced by a global research team called the Event Horizon Telescope (EHT) Collaboration, using observations from a worldwide network of radio telescopes. The image is a long-anticipated look at the massive object that sits at the very centre of our galaxy. Scientists had previously seen stars orbiting around something invisible, compact, and very massive at the centre of the Milky Way. This strongly suggested that this object -- known as Sagittarius A* (Sgr A*, pronounced "sadge-ay-star") -- is a black hole, and today's image provides the first direct visual evidence of it. Although we cannot see the black hole itself, because it is completely dark, glowing gas around it reveals a telltale signature: a dark central region (called a shadow) surrounded by a bright ring-like structure. The new view captures light bent by the powerful gravity of the black hole, which is four million times more massive than our Sun. Because the black hole is about 27 000 light-years away from Earth, it appears to us to have about the same size in the sky as a doughnut on the Moon. To image it, the team created the powerful EHT, which linked together eight existing radio observatories across the planet to form a single "Earth-sized" virtual telescope. The EHT observed Sgr A* on multiple nights in 2017, collecting data for many hours in a row, similar to using a long exposure time on a camera. In addition to other facilities, the EHT network of radio observatories includes the Atacama Large Millimeter/submillimeter Array (ALMA) and the Atacama Pathfinder EXperiment (APEX) in the Atacama Desert in Chile, co-owned and co-operated by ESO on behalf of its member states in Europe. Europe also contributes to the EHT observations with other radio observatories -- the IRAM 30-meter telescope in Spain and, since 2018, the NOrthern Extended Millimeter Array (NOEMA) in France -- as well as a supercomputer to combine EHT data hosted by the Max Planck Institute for Radio Astronomy in Germany. Moreover, Europe contributed with funding to the EHT consortium project through grants by the European Research Council and by the Max Planck Society in Germany.

The EHT achievement follows the collaboration's 2019 release of the first image of a black hole, called M87*, at the centre of the more distant Messier 87 galaxy. The two black holes look remarkably similar, even though our galaxy's black hole is more than a thousand times smaller and less massive than M87*. The researchers had to develop sophisticated new tools that accounted for the gas movement around Sgr A*. While M87* was an easier, steadier target, with nearly all images looking the same, that was not the case for Sgr A*. The image of the Sgr A* black hole is an average of the different images the team extracted, finally revealing the giant lurking at the centre of our galaxy for the first time. The effort was made possible through the ingenuity of more than 300 researchers from 80 institutes around the world that together make up the EHT Collaboration. In addition to developing complex tools to overcome the challenges of imaging Sgr A*, the team worked rigorously for five years, using supercomputers to combine and analyse their data, all while compiling an unprecedented library of simulated black holes to compare with the observations. Scientists are particularly excited to finally have images of two black holes of very different sizes, which offers the opportunity to understand how they compare and contrast. They have also begun to use the new data to test theories and models of how gas behaves around supermassive black holes. This process is not yet fully understood but is thought to play a key role in shaping the formation and evolution of galaxies.


Bulletin compiled by Clive Down
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Science and Technology / Mega-Bridges
May 19, 2022, 08:01:38 pm
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THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 565 2022 May 8

We're delighted that the Society for Popular Astronomy's free Electronic News Bulletins have gained many hundreds of subscribers since we first issued them more than 23 years ago!

They remain free, but if you are not already a member of the SPA, we hope you will consider joining, and supporting the UK's liveliest astronomical society, with members worldwide. You can easily sign up online. https://www.popastro.com/main_...

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WHY VENUS ROTATES SLOWLY
University of California - Riverside

If not for the soupy, fast-moving atmosphere on Venus, Earth's sister planet would likely not rotate. Instead, Venus would be locked in place, always facing the Sun the way the same side of the Moon always faces Earth. The gravity of a large object in space can keep a smaller object from spinning, a phenomenon called tidal locking. Because it prevents this locking, it can be argued the atmosphere needs to be a more prominent factor in studies of Venus as well as other planets. Venus takes 243 Earth days to rotate one time, but its atmosphere circulates the planet every four days. Extremely fast winds cause the atmosphere to drag along the surface of the planet as it circulates, slowing its rotation while also loosening the grip of the Sun's gravity. Slow rotation in turn has dramatic consequences for the sweltering Venusian climate, with average temperatures of up to 900 degrees Fahrenheit -- hot enough to melt lead. One reason for the heat is that nearly all of the Sun's energy absorbed by the planet is soaked up by Venus' atmosphere, never reaching the surface. This means that a rover with solar panels like the one NASA sent to Mars wouldn't work. The Venusian atmosphere also blocks the Sun's energy from leaving the planet, preventing cooling or liquid water on its surface, a state known as a runaway greenhouse effect. It is unclear whether being partially tidally locked contributes to this runaway greenhouse state, a condition which ultimately renders a planet uninhabitable by life as we know it.

Not only is it important to gain clarity on this question to understand Venus, it is important for studying the exoplanets likely to be targeted for future NASA missions. Most of the planets likely to be observed with the recently launched James Webb Space Telescope are very close to their stars, even closer than Venus is to the Sun. Therefore, they're also likely to be tidally locked. Since humans may never be able to visit exoplanets in person, making sure computer models account for the effects of tidal locking is critical. Venus is our opportunity to get these models correct, so we can properly understand the surface environments of planets around other stars. Gaining clarity about the factors that contributed to a runaway greenhouse state on Venus, Earth's closest planetary neighbour, can also help improve models of what could one day happen to Earth's climate.

TITAN IS EARTH-LIKE ALIEN WORLD
Stanford University

Saturn's moon Titan looks very much like Earth from space, with rivers, lakes, and seas filled by rain tumbling through a thick atmosphere. While these landscapes may look familiar, they are composed of materials that are undoubtedly different -- liquid methane streams streak Titan's icy surface and nitrogen winds build hydrocarbon sand dunes. The presence of these materials -- whose mechanical properties are vastly different from those of silicate-based substances that make up other known sedimentary bodies in our solar system -- makes Titan's landscape formation enigmatic. By identifying a process that would allow for hydrocarbon-based substances to form sand grains or bedrock depending on how often winds blow and streams flow, scientists have shown how Titan's distinct dunes, plains, and labyrinth terrains could be formed. Titan, which is a target for space exploration because of its potential habitability, is the only other body in our solar system known to have an Earth-like, seasonal liquid transport cycle today. The new model shows how that seasonal cycle drives the movement of grains over the moon's surface. In order to build a model that could simulate the formation of Titan's distinct landscapes, scientists first had to solve one of the biggest mysteries about sediment on the planetary body: How can its basic organic compounds -- which are thought to be much more fragile than inorganic silicate grains on Earth -- transform into grains that form distinct structures rather than just wearing down and blowing away as dust? On Earth, silicate rocks and minerals on the surface erode into sediment grains over time, moving through winds and streams to be deposited in layers of sediments that eventually -- with the help of pressure, groundwater, and sometimes heat -- turn back into rocks. Those rocks then continue through the erosion process and the materials are recycled through Earth's layers over geologic time. On Titan, researchers think similar processes formed the dunes, plains, and labyrinth terrains seen from space. But unlike on Earth, Mars, and Venus, where silicate-derived rocks are the dominant geological material from which sediments are derived, Titan's sediments are thought to be composed of solid organic compounds. Scientists haven't been able to demonstrate how these organic compounds may grow into sediment grains that can be transported across the moon's landscapes and over geologic time.

The research team found an answer by looking at sediments on Earth called ooids, which are small, spherical grains most often found in shallow tropical seas, such as around the Bahamas. Ooids form when calcium carbonate is pulled from the water column and attaches in layers around a grain, such as quartz. What makes ooids unique is their formation through chemical precipitation, which allows ooids to grow, while the simultaneous process of erosion slows the growth as the grains are smashed into each other by waves and storms. These two competing mechanisms balance each other out through time to form a constant grain size -- a process the researchers suggest could also be happening on Titan. Armed with a hypothesis for sediment formation, the teamors used existing data about Titan's climate and the direction of wind-driven sediment transport to explain its distinct parallel bands of geological formations: dunes near the equator, plains at the mid-latitudes, and labyrinth terrains near the poles. Atmospheric modelling and data from the Cassini mission reveal that winds are common near the equator, supporting the idea that less sintering and therefore fine sand grains could be created there -- a critical component of dunes. The study authors predict a lull in sediment transport at mid-latitudes on either side of the equator, where sintering could dominate and create coarser and coarser grains, eventually turning into bedrock that makes up Titan's plains. Sand grains are also necessary for the formation of the moon's labyrinth terrains near the poles. Researchers think these distinct crags could be like karsts in limestone on Earth -- but on Titan, they would be collapsed features made of dissolved organic sandstones. River flow and rainstorms occur much more frequently near the poles, making sediments more likely to be transported by rivers than winds. A similar process of sintering and abrasion during river transport could provide a local supply of coarse sand grains -- the source for the sandstones thought to make up labyrinth terrains. It shows that on Titan -- just like on Earth and what used to be the case on Mars -- we have an active sedimentary cycle that can explain the latitudinal distribution of landscapes through episodic abrasion and sintering driven by Titan's seasons.

NEW LIGHT ON STRANGE SIGNAL FROM GALACTIC CENTRE
Australian National University

Researchers have found an alternative explanation for a mysterious gamma-ray signal coming from the centre of the Galaxy, which was long claimed as a signature of dark matter. Gamma-rays are the form of electromagnetic radiation with the shortest wavelength and highest energy. This particular gamma-ray signal -- known as the Galactic Centre Excess -- may actually come from a specific type of rapidly-rotating neutron star, the super-dense stellar remnants of some stars much more massive than our Sun. The Galactic Centre Excess is an unexpected concentration of gamma-rays emerging from the centre of our galaxy that has long puzzled astronomers. The work does not throw any doubt on the existence of the signal, but offers another potential source based on millisecond pulsars -- neutron stars that spin really quickly -- around 100 times a second. Scientists have previously detected gamma-ray emissions from individual millisecond pulsars in the neighbourhood of the solar system, so we know these objects emit gamma-rays. The model demonstrates that the integrated emission from a whole population of such stars, around 100,000 in number, would produce a signal entirely compatible with the Galactic Centre Excess. The discovery may mean scientists have to re-think where they look for clues about dark matter.

LIKELY LOCATION OF MEDIUM-SIZED BLACK HOLES
Washington State University

Intermediate-mass black holes are notoriously hard to find but a new study indicates there may be some at the centre of dense star clusters located throughout the Universe. The study sheds new light on when and where black holes of about 100-100,000 solar masses could form and how they came into being. One of the biggest open questions in black hole astrophysics right now is how do black holes form that are between the size of a stellar mass black hole and a supermassive black hole. Most of the theories for their formation rely on conditions that are found only in the very early Universe. Scientists wanted to test another theory that says they can form throughout cosmic time in these really dense star clusters. For decades, astronomers have detected smaller black holes equal in mass either to a few suns or giant black holes with mass similar to millions of suns but the missing-link of black holes in between those sizes have eluded discovery. The existence of these intermediate-sized or massive black holes has long been theorized but finding them has proven difficult as the light emitted by objects falling into them is not easy to detect. To address this challenge, the research team used the Chandra X-Ray Observatory, the world's most powerful X-ray telescope, to look for X-ray signatures of black holes in nuclear star clusters in 108 different galaxies. Nuclear star clusters are found at the centre of most small or low-mass galaxies and are the densest known stellar environments. Previous research has identified the presence of black holes in nuclear star clusters but little is known about the specific properties that make these regions conducive for the formation of black holes.

The team showed that nuclear star clusters that were above a certain mass and density threshold emitted the X-ray signatures indicative of a black hole at twice the rate of those below the threshold. Their work provides the first observational evidence supporting the theory that intermediate-sized black holes can form in nuclear star clusters. Basically, it means that star clusters that are sufficiently massive and compact should be able to form a blackhole. It is exciting because researchers expect many of these black holes to be in the intermediate mass regime between supermassive black holes and stellar mass black holes where there is very little evidence for their existence. The research team's work not only suggests that intermediate-sized black holes can form in nuclear star clusters but also provides a mechanism by which they could potentially form throughout cosmic time rather than just during the first few billion years of the Universe. One of the prevailing theories is that massive black holes could only have formed during the early Universe when things were more dense. This research is more consistent with the picture where massive blackholes don't need to form in the very early Universe but could rather continue to form throughout cosmic time in these particular environments. Moving forward, the researchers plan to continue using Chandra to collect x-ray measurements of nuclear star clusters with the ultimate goal of learning more about the specific conditions where massive black holes can form.

SUPERNOVA REVEALS SECRETS
University of Texas at Austin

Astronomers have used observations from the Hobby-Eberly Telescope (HET) at the university's McDonald Observatory to unlock a puzzling mystery about a stellar explosion discovered several years ago and evolving even now. When an exploding star is first detected, astronomers around the world begin to follow it with telescopes as the light it gives off changes rapidly over time. They see the light from a supernova get brighter, eventually peak, and then start to dim. By noting the times of these peaks and valleys in the light's brightness, called a "light curve," as well as the characteristic wavelengths of light emitted at different times, they can deduce the physical characteristics of the system. In the case of supernova 2014C, the progenitor was a binary star, a system in which two stars were orbiting each other. The more massive star evolved more quickly, expanded, and lost its outer blanket of hydrogen to the companion star. The first star's inner core continued burning lighter chemical elements into heavier ones, until it ran out of fuel. When that happened, the outward pressure from the core that had held up the star's great weight dropped. The star's core collapsed, triggering a gigantic explosion. This makes it a type of supernova astronomers call a "Type Ib." In particular, Type Ib supernovae are characterized by not showing any hydrogen in their ejected material, at least at first. The team has been following SN 2014C from telescopes at McDonald Observatory since its discovery that year. Many other teams around the world also have studied it with telescopes on the ground and in space, and in different types of light, including radio waves from the ground-based Very Large Array, infrared light, and X-rays from the space-based Chandra Observatory. But the studies of SN 2014C from all of the various telescopes did not add up into a cohesive picture of how astronomers thought a Type Ib supernova should behave.

For one thing, the optical signature from the Hobby-Eberly Telescope (HET) showed SN 2014C contained hydrogen -- a surprising finding that also was discovered independently by another team using a different telescope. For a second thing, the optical brightness (light curve) of that hydrogen was behaving strangely. Most of the light curves from SN 2014C -- radio, infrared, and X-rays -- followed the expected pattern: they got brighter, peaked, and started to fall. But the optical light from the hydrogen stayed steady. The problem, the team realized, was that previous models of this system assumed that the supernova had exploded and sent out its shockwave in a spherical manner. The data from HET showed that this hypothesis was impossible -- something else must have happened. The team proposes a model where the hydrogen envelopes of the two stars in the progenitor binary system merged to form a "common-envelope configuration," where both were contained within a single envelope of gas. The pair then expelled that envelope in an expanding, disk-like structure surrounding the two stars. When one of the stars exploded, its fast-moving ejecta collided with the slow-moving disk, and also slid along the disk surface at a "boundary layer" of intermediate velocity. The team suggests that this boundary layer is the origin of the hydrogen they detected and then studied for seven years with HET. Thus the HET data turned out to be the key that unlocked the mystery of supernova SN 2014C.

Bulletin compiled by Clive Down

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11
Astronomy / The Night Sky in May 2022
May 01, 2022, 12:43:28 pm
For deep-sky observers, May means galaxy season as we stargazers get a view out of the plane of the Milky Way into
the intergalactic void. The Eta Aquarid meteor shower peaks in the first week of the month, and for much of the
world, a total lunar eclipse occurs at mid-month during the 'Full Flower Moon'. Here's what to see in the night sky this month...

To see "the Night Sky in May" CLICK HERE

12
Astronomy / Preseli Astronomy Group
April 28, 2022, 10:33:27 am
What Happened at The Big Bang!

Preseli Astronomy Group.

Letterston Memorial Hall, 7.30am Tuesday 3rd May


New Scientist online lecture September 2020. Dan Hooper, theoretical astrophysicist, Fermi National Accelerator Laboratory. Explore the mysteries of the universe's first seconds. Over the past few decades, we have made incredible discoveries about how our cosmos evolved over the past 13.8 billion years. But there remains a critical gap in our knowledge: we still know very little about what happened in the first seconds after the big bang.
13
 
THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 563 2022 April 24

We're delighted that the Society for Popular Astronomy's free Electronic News Bulletins have gained many hundreds of subscribers since we first issued them more than 23 years ago!

They remain free, but if you are not already a member of the SPA, we hope you will consider joining, and supporting the UK's liveliest astronomical society, with members worldwide. You can easily sign up online. https://www.popastro.com/main_...

And now, here is our latest round-up of news.

FIRST KNOWN INTERSTELLAR OBJECT ON EARTH
United States Space Command

A small meteor that hit Earth in 2014 was from another star system, and may have left interstellar debris on the seafloor. The meteor ignited in a fireball in the skies near Papua New Guinea, the memo states, and scientists believe it possibly sprinkled interstellar debris into the South Pacific Ocean. The confirmation backs up the breakthrough discovery of the first interstellar meteor--and, retroactively, the first known interstellar object of any kind to reach our solar system--which was initially flagged by Harvard University researchers. The discovery of the meteor, which measured just a few feet wide, follows recent detections of two other interstellar objects in our solar system, known as 'Oumuamua and Comet Borisov, that were much larger and did not come into close contact with Earth. There are nearly 1,000 impacts logged in the database, but a fireball that exploded near Manus Island on January 8, 2014 jumped out at researchers owing to an unusually swift speed exceeding 130,000 miles per hour. This breakneck pace hinted at "a possible origin from the deep interior of a planetary system or a star in the thick disk of the Milky Way galaxy of the solar system."

Some of the sensors that detect fireballs are operated by the U.S. Department of Defense, which uses the same technologies to monitor the skies for nuclear detonations. As a result, the team couldn't directly confirm the margin of error on the fireball's velocity. The secret data threw the paper into limbo as the researchers sought to get confirmation from the U.S. government. The newly released memo, which is dated March 1 of this year, reveals that the velocity estimate reported to NASA is sufficiently accurate to indicate an interstellar trajectory. Any information about the light emitted by the object as it burned up in the atmosphere could yield insights about the interior composition of the interstellar visitor. While this was an incredibly small object, it indicates that the solar system may be awash in material from other star systems, and indeed even other galaxies, that could be turned up by future searches. Such efforts could offer a glimpse of the worlds beyond the Sun right here on Earth, and perhaps even unearth bonafide interstellar meteorites.

RELIC FROM EARLY SOLAR SYSTEM TO VISIT
University of California - Los Angeles

An enormous comet -- approximately 80 miles across is heading our way at 22,000 miles per hour from the edge of the solar system. Fortunately, it will never get closer than 1 billion miles from the Sun, which is slightly farther from Earth than Saturn; that will be in 2031. Comets, among the oldest objects in the solar system, are icy bodies that were unceremoniously tossed out of the solar system in a gravitational pinball game among the massive outer planets. The evicted comets took up residence in the Oort cloud, a vast reservoir of far-flung comets encircling the solar system out to many billions of miles into deep space. A typical comet's spectacular multimillion-mile-long tail, which makes it look like a skyrocket, belies the fact that the source at the heart of the fireworks is a solid nucleus of ice mixed with dust -- essentially a dirty snowball. This huge one, called Comet C/2014 UN271 and discovered by astronomers Pedro Bernardinelli and Gary Bernstein, could be as large as 85 miles across. This comet has the largest nucleus ever seen in a comet by astronomers. I ts nucleus is about 50 times larger than those of most known comets. Its mass is estimated to be 500 trillion tons, a hundred thousand times greater than the mass of a typical comet found much closer to the Sun. The researchers used Hubble to take five photos of the comet on Jan. 8, 2022, and incorporated radio observations of the comet into their analysis.

The comet is now less than 2 billion miles from the Sun and in a few million years will loop back to its nesting ground in the Oort cloud, Comet C/2014 UN271 was first serendipitously observed in 2010, when it was 3 billion miles from the Sun. Since then, it has been intensively studied by ground and space-based telescopes. The challenge in measuring this comet was how to determine the solid nucleus from the huge dusty coma -- the cloud of dust and gas -- enveloping it. The comet is currently too far away for its nucleus to be visually resolved by Hubble. Instead, the Hubble data show a bright spike of light at the nucleus' location. Astronomers compared the brightness of the nucleus to earlier radio observations from the Atacama Large millimeter/submillimeter Array, or ALMA, in Chile. The new Hubble measurements are close to the earlier size estimates from ALMA, but convincingly suggest a darker nucleus surface than previously thought. The comet has been falling toward the Sun for well over 1 million years. The Oort cloud is thought to be the nesting ground for trillions of comets. It is believed the Oort cloud extends from a few hundred times the distance between the Sun and the Earth to at least a quarter of the way out to the distance of the nearest stars to our sun, in the Alpha Centauri system. The Oort cloud's comets were tossed out of the solar system billions of years ago by the gravitation of the massive outer planets, according. The far-flung comets travel back toward the Sun and planets only if their orbits are disturbed by the gravitational tug of a passing star. First hypothesized in 1950 by Dutch astronomer Jan Oort, the Oort cloud still remains a theory because the comets that make it up are too faint and distant to be directly observed. This means the solar system's largest structure is all but invisible.

JUPITER'S MOON HAS SPLENDID DUNES
Rutgers University

Scientists have long wondered how Jupiter's innermost Moon, Io, has meandering ridges as grand as any that can be seen in movies like "Dune." Now, a research study has provided a new explanation of how dunes can form even on a surface as icy and roiling as Io's. The study is based on the physical processes controlling grain motion coupled with an analysis of images from the 14-year mission of NASA's Galileo spacecraft, which allowed the creation of the first detailed maps of Jupiter's moons. The new study is expected to expand our scientific understanding of the geological features on these planet-like worlds. Current scientific understanding dictates that dunes, by their nature, are hills or ridges of sand piled up by the wind. And scientists in previous studies of Io, while describing its surface as containing some dune-like features, concluded the ridges could not be dunes since the forces from winds on Io are weak due to the moon's low-density atmosphere. The Galileo mission, which lasted from 1989 -- 2003, logged so many scientific firsts that researchers to this day are still studying the data it collected. One of the major insights gleaned from the data was the high extent of volcanic activity on Io -- so much so that its volcanoes repeatedly and rapidly resurface the little world. Io's surface is a mix of black solidified lava flows and sand, flowing "effusive" lava streams, and "snows" of sulphur dioxide. The scientists used mathematical equations to simulate the forces on a single grain of basalt or frost and calculate its path. When lava flows into sulphur dioxide beneath the moon's surface, its venting is "dense and fast moving enough to move grains on Io and possibly enable the formation of large-scale features like dunes. Once the researchers devised a mechanism by which the dunes could form, they looked to photos of Io's surface taken by the Galileo spacecraft for more proof. The spacing of the crests and the height-to-width ratios they observed were consistent with trends for dunes seen on Earth and other planets.

NEPTUNE'S SURPRISING TEMPERATURE CHANGES
ESO

Astronomers have used ground-based telescopes, including the European Southern Observatory's Very Large Telescope (ESO's VLT), to track Neptune's atmospheric temperatures over a 17-year period. They found a surprising drop in Neptune's global temperatures followed by a dramatic warming at its south pole. Like Earth, Neptune experiences seasons as it orbits the Sun. However, a Neptune season lasts around 40 years, with one Neptune year lasting 165 Earth years. It has been summertime in Neptune's southern hemisphere since 2005, and the astronomers were eager to see how temperatures were changing following the southern summer solstice. Astronomers looked at nearly 100 thermal-infrared images of Neptune, captured over a 17-year period, to piece together overall trends in the planet's temperature in greater detail than ever before. These data showed that, despite the onset of southern summer, most of the planet had gradually cooled over the last two decades. The globally averaged temperature of Neptune dropped by 8 °C between 2003 and 2018. The astronomers were then surprised to discover a dramatic warming of Neptune's south pole during the last two years of their observations, when temperatures rapidly rose 11 °C between 2018 and 2020. Although Neptune's warm polar vortex has been known for many years, such rapid polar warming has never been previously observed on the planet.

The astronomers measured Neptune's temperature using thermal cameras that work by measuring the infrared light emitted from astronomical objects. For their analysis the team combined all existing images of Neptune gathered over the last two decades by ground-based telescopes. They investigated infrared light emitted from a layer of Neptune's atmosphere called the stratosphere. This allowed the team to build up a picture of Neptune's temperature and its variations during part of its southern summer. Because Neptune is roughly 4.5 billion kilometres away and is very cold, the planet's average temperature reaching around -220°C, measuring its temperature from Earth is no easy task. Around one third of all the images taken came from the VLT Imager and Spectrometer for mid-InfraRed (VISIR) instrument on ESO's VLT in Chile's Atacama Desert. Because of the telescope's mirror size and altitude, it has a very high resolution and data quality, offering the clearest images of Neptune. The team also used data from NASA's Spitzer Space Telescope and images taken with the Gemini South telescope in Chile, as well as with the Subaru Telescope, the Keck Telescope, and the Gemini North telescope, all in Hawai'i. Because Neptune's temperature variations were so unexpected, the astronomers do not know yet what could have caused them. They could be due to changes in Neptune's stratospheric chemistry, or random weather patterns, or even the solar cycle. More observations will be needed over the coming years to explore the reasons for these fluctuations. Future ground-based telescopes like ESO's Extremely Large Telescope (ELT) could observe temperature changes like these in greater detail, while the NASA/ESA/CSA James Webb Space Telescope will provide unprecedented new maps of the chemistry and temperature in Neptune's atmosphere.

EXOCOMETS FOUND AROUND ANOTHER STAR
Science

When a comet dives near the Sun, it's a spectacular and rare sight from here on Earth. Our solar system, however, is full of these tiny chunks of ice, spinning far from the Sun in the distant Oort cloud. Given the ubiquity of comets here, scientists think other planetary systems probably have them too. Ukrainian recently published a discovery of five new exocomets -- comets that orbit a star other than the Sun. They also independently confirmed a handful of exocomets previously detected by other researchers. Within our solar system, comets are studied as remnants of the past and provide clues to the chemistry of the formation of Earth and its neighbouring planets. They are also a particularly important part of Earth's story, as comets are believed to have brought water to Earth, making our planet bursting with life. These newly discovered exocomets orbit the star Beta Pictoris, a well-studied favourite of astronomers that is only about 65 light-years from Earth. Beta Pictoris is much younger than the Sun, only 10 to 40 million years old compared to the solar system's 4.5 billion years, making it a useful snapshot of what happens during its youth. a planetary system. This star orbits a gas giant planet 11 times larger than Jupiter (called Beta Pic b) and a huge disk of dust nearly 40 billion miles in diameter, known as a debris disk.

Debris disks represent the "older" era of planet-forming disks -- the later stage in the complex dance of dust and gas that form full-fledged planets like those around the Sun. These disks are often chaotic and violent places, with chunks of rock and protoplanets flying around and colliding. That's where exocomets come in. In younger planetary systems like Beta Pic, comets are much more likely to dive near their stars because everything on the disk is still shifting before objects settle into their final configuration. In fact, this discovery isn't even the first time exocomets have been seen around Beta Pic -- the first detection with TESS occurred in 2019, and previous studies inferred that Beta Pic actually has two distinct groups of exocomets with different properties. The new exocomets add to a growing stack of exocomet discoveries around multiple stars from both TESS and its predecessor, the planet-hunting Kepler Space Telescope. While these observatories aren't the first to spot exocomets in one form or another, they're the first to detect them directly through transits -- tiny dips in the amount of light we see from a star as a comet passes in front. First observed in Kepler data in 2017, comet transits are steeper and skewed than exoplanet transits, due in part to the comet's long tail. Transits show how big the exocomet is, while other discovery methods can measure the comet's speed and orbit. When combined, all of this information provides a more complete picture of what's going on with exocomets -- how they're born and how they change. By building a large catalogue of exocomet transits around many different stars, astronomers can discover patterns in the data, potentially revealing trends caused by the process of planet formation.

NOVA OUTBURSTS ARE SOURCE OF COSMIC RAYS
Max Planck Institute for Physics

Every 15 years or so, a dramatic explosion occurs in the constellation of Ophiuchus. Birthplaces of a nova are systems in which two very different stars live in a parasitic relationship: A white dwarf, a small, burned-out and tremendously dense star -- a teaspoon of its matter weighs about 1 ton -- orbits a red giant, an old star that will soon burn up. The dying giant star RS Ophiuchi (RS Oph) feeds the white dwarf with matter shedding its outer hydrogen layer as the gas flows onto the nearby white dwarf. This flow of matter continues, until the white dwarf overheats itself. The temperature and pressure in the newly gained stellar shells become too large and are flung away in a gigantic thermonuclear explosion. The dwarf star remains intact and the cycle begins again -- until the spectacle repeats itself. It had been speculated that such explosions involve high energies. The two MAGIC telescopes recorded gamma rays with the value of 250 gigaelectronvolts (GeV), among the highest energies ever measured in a nova. By comparison, the radiation is a hundred billion times more energetic than visible light. MAGIC was able to make its observations following initial alerts from other instruments measuring at different wavelengths. "The spectacular eruption of the RS Ophiuchi shows that the MAGIC telescopes' fast response really pays off: It takes them no more than 30 seconds to move to a new target," said David Green, a scientist at the Max Planck Institute for Physics and one of the authors of the paper. After the explosion, several shock fronts propagated through the stellar wind from the Red Giant and the interstellar medium surrounding the binary system. These shock waves work like a giant power plant in which particles are accelerated to near the speed of light. The combined measurements suggest that the gamma rays emanate from energetic protons, nuclei of hydrogen atoms. To fully understand the complicated interplay of violent events with the interstellar medium in the Milky Way, more observations like those reported now will be necessary. The MAGIC collaboration will therefore continue to look for "restless" objects in our Galaxy and beyond.

MICRONOVAE, A NEW KIND OF STELLAR EXPLOSION
ESO

A team of astronomers using the Very Large Telescope (ESO's VLT), have observed a new type of stellar explosion -- a micronova. These outbursts happen on the surface of certain stars, and can each burn through around 3.5 billion Great Pyramids of Giza of stellar material in only a few hours. Micronovae are extremely powerful events, but are small on astronomical scales; they are much less energetic than the stellar explosions known as novae, which astronomers have known about for centuries. Both types of explosions occur on white dwarfs, dead stars with a mass about that of our Sun, but as small as Earth. A white dwarf in a two-star system can steal material, mostly hydrogen, from its companion star if they are close enough together. As this gas falls onto the very hot surface of the white dwarf star, it triggers the hydrogen atoms to fuse into helium explosively. In novae, these thermonuclear explosions occur over the entire stellar surface. Micronovae are similar explosions that are smaller in scale and faster, lasting just several hours. They occur on some white dwarfs with strong magnetic fields, which funnel material towards the star's magnetic poles. These new micronovae challenge astronomers' understanding of stellar explosions and may be more abundant than previously thought. The team first came across these mysterious micro-explosions when analysing data from NASA's Transiting Exoplanet Survey Satellite (TESS). It observed three micronovae with TESS: two were from known white dwarfs, but the third required further observations with the X-shooter instrument on ESO's VLT to confirm its white dwarf status.The discovery of micronovae adds to the repertoire of known stellar explosions.

ORIGINS OF SUPERMASSIVE BLACK HOLES
NASA/Goddard Space Flight Center

Astronomers have identified a rapidly growing black hole in the early Universe that is considered a crucial "missing link" between young star-forming galaxies and the first supermassive black holes. They used data from NASA's Hubble Space Telescope to make this discovery. Until now, the monster, nicknamed GNz7q, had been lurking unnoticed in one of the best-studied areas of the night sky, the Great Observatories Origins Deep Survey-North (GOODS-North) field. Archival Hubble data from Hubble's Advanced Camera for Surveys helped the team determine that GNz7q existed just 750 million years after the big bang. The team obtained evidence that GNz7q is a newly formed black hole. Hubble found a compact source of ultraviolet (UV) and infrared light. This couldn't be caused by emission from galaxies, but is consistent with the radiation expected from materials that are falling onto a black hole. Rapidly growing black holes in dusty, early star-forming galaxies are predicted by theories and computer simulations, but had not been observed until now. One of the outstanding mysteries in astronomy today is: How did supermassive black holes, weighing millions to billions of times the mass of the Sun, get to be so huge so fast? Current theories predict that supermassive black holes begin their lives in the dust-shrouded cores of vigorously star-forming "starburst" galaxies before expelling the surrounding gas and dust and emerging as extremely luminous quasars. While extremely rare, both these dusty starburst galaxies and luminous quasars have been detected in the early Universe.

The team believes that GNz7q could be a missing link between these two classes of objects. GNz7q has exactly both aspects of the dusty starburst galaxy and the quasar, where the quasar light shows the dust reddened colour. Also, GNz7q lacks various features that are usually observed in typical, very luminous quasars (corresponding to the emission from the accretion disk of the supermassive black hole), which is most likely explained that the central black hole in GN7q is still in a young and less massive phase. These properties perfectly match with the young, transition phase quasar that has been predicted in simulations, but never identified at similarly high-redshift Universe as the very luminous quasars so far identified up to a redshift of 7.6. While other interpretations of the team's data cannot be completely ruled out, the observed properties of GNz7q are in strong agreement with theoretical predictions. GNz7q's host galaxy is forming stars at the rate of 1,600 solar masses per year, and GNz7q itself appears bright at UV wavelengths but very faint at X-ray wavelengths. Generally, the accretion disk of a massive black hole should be very bright in both UV and X-ray light. But this time, although the team detected UV light with Hubble, X-ray light was invisible even with one of the deepest X-ray datasets. These results suggest that the core of the accretion disk, where X-rays originate, is still obscured; while the outer part of the accretion disk, where UV light originates, is becoming unobscured. This interpretation is that GNz7q is a rapidly growing black hole still obscured by the dusty core of its star-forming host galaxy. Finding GNz7q hiding in plain sight was only possible thanks to the uniquely detailed, multiwavelength datasets available for GOODS-North. Without this richness of data GNz7q would have been easy to overlook, as it lacks the distinguishing features usually used to identify quasars in the early Universe. The team now hopes to systematically search for similar objects using dedicated high-resolution surveys and to take advantage of the NASA James Webb Space Telescope's spectroscopic instruments to study objects such as GNz7q in unprecedented detail.

HUNTING FOR GRAVITATIONAL WAVES FROM MONSTER BLACK HOLES
NASA/Goddard Space Flight Center

Our Universe is a chaotic sea of ripples in space-time called gravitational waves. Astronomers think waves from orbiting pairs of supermassive black holes in distant galaxies are light-years long and have been trying to observe them for decades, and now they're one step closer thanks to NASA's Fermi Gamma-ray Space Telescope. Fermi detects gamma rays, the highest-energy form of light. An international team of scientists examined over a decade of Fermi data collected from pulsars, rapidly rotating cores of stars that exploded as supernovae. They looked for slight variations in the arrival time of gamma rays from these pulsars, changes which could have been caused by the light passing through gravitational waves on the way to Earth. But they didn't find any. While no waves were detected, the analysis shows that, with more observations, these waves may be within Fermi's reach. When massive objects accelerate, they produce gravitational waves travelling at light speed. The ground-based Laser Interferometer Gravitational Wave Observatory -- which first detected gravitational waves in 2015 -- can sense ripples tens to hundreds of miles long from crest to crest, which roll past Earth in just fractions of a second. The upcoming space-based Laser Interferometer Space Antenna will pick up waves millions to billions of miles long. Researchers are searching for waves that are light-years, or trillions of miles, long and take years to pass Earth. These long ripples are part of the gravitational wave background, a random sea of waves generated in part by pairs of supermassive black holes in the centres of merged galaxies across the Universe. To find them, scientists need galaxy-sized detectors called pulsar timing arrays. These arrays use specific sets of millisecond pulsars, which rotate as fast as blender blades. Millisecond pulsars sweep beams of radiation, from radio to gamma rays, past our line of sight, appearing to pulse with incredible regularity -- like cosmic clocks.

As long gravitational waves pass between one of these pulsars and Earth, they delay or advance the light arrival time by billionths of a second. By looking for a specific pattern of pulse variations among pulsars of an array, scientists expect they can reveal gravitational waves rolling past them. Radio astronomers have been using pulsar timing arrays for decades, and their observations are the most sensitive to these gravitational waves. But interstellar effects complicate the analysis of radio data. Space is speckled with stray electrons. Across light-years, their effects combine to bend the trajectory of radio waves. This alters the arrival times of pulses at different frequencies. Gamma rays don't suffer from these complications, providing both a complementary probe and an independent confirmation of the radio results. The Fermi results are already 30% as good as the radio pulsar timing arrays when it comes to potentially detecting the gravitational wave background. With another five years of pulsar data collection and analysis, it'll be equally capable with the added bonus of not having to worry about all those stray electrons. Within the next decade, both radio and gamma-ray astronomers expect to reach sensitivities that will allow them to pick up gravitational waves from orbiting pairs of monster black holes.

BIGGEST REVOLUTION IN PHYSICS SINCE EINSTEIN
Science

Scientists outside Chicago, USA, have discovered that the mass of a subatomic particle is not what it should be - a surprising discovery that could revolutionize physics and our understanding of the Universe. The measurement is the first conclusive result of an experiment that is at odds with one of the most important and successful theories in modern physics. The team found that the particle, known as the W boson, has more mass than theories predicted. The discovery could lead to the development of a new and more complete theory of how the Universe works. Scientists at the CDF (Fermilab Collider Detector) in the US state of Illinois found only a small difference in the mass of the W boson compared to what theory says it should be -- just 0.1% . But if this is confirmed by other experiments, the implications are enormous. The so-called Standard Model of particle physics has predicted the behaviour and properties of subatomic particles without any discrepancy for 50 years. So far. The conclusion may be linked to clues from other experiments at Fermilab and the Large Hadron Collider on the Swiss-French border. These as-yet-unconfirmed conclusions also suggest deviations from the Standard Model, possibly as a result of an as-yet-undiscovered fifth force of nature at play. Physicists have known for some time that the theory needs updating. The concept is not able to explain the presence of invisible material in space, called Dark Matter, nor the continuous accelerated expansion of the Universe by a force called Dark Energy. Neither does gravity. But despite the enthusiasm, the physical community remains cautious. While the Fermilab result is the most accurate measurement of the W boson mass to date, it is at odds with two of the next most accurate measurements from two separate experiments that conform to the Standard Model. All eyes are now on the Large Hadron Collider, which is set to restart its experiments after a three-year renovation. The hope is that these tests will provide the results that will lay the groundwork for a more complete new theory of physics.


Bulletin compiled by Clive Down



 




15
Family History / Lost Cousin's Newsletter
April 10, 2022, 03:41:57 pm
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THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 563 2022 April 10
We're delighted that the Society for Popular Astronomy's free Electronic News Bulletins have gained many hundreds of subscribers since we first issued them more than 23 years ago!
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SCIENTISTS SOLVE SOLAR SECRET
University of Otago
The further we move a
way from a heat source, the cooler the air gets. Bizarrely, the same can't be said for the Sun, but scientists may have just explained a key part of why. The surface of the Sun starts at 6000 degree C, but over a short distance of only a few hundred kilometers, it suddenly heats up to more than a million degrees, becoming its atmosphere, or corona. This is so hot that the gas escapes the Sun's gravity as 'solar wind', and flies into space, smashing into Earth and other planets. Scientists know from measurements and theory that the sudden temperature jump is related to magnetic fields which thread out of the Sun's surface. But, exactly how these work to heat the gas is not well understood -- this is known as the Coronal Heating Problem. Astrophysicists have several different ideas about how the magnetic-field energy could be converted into heat to explain the heating, but most have difficulty explaining some aspect of observations. The popular theories are based on heating caused by turbulence, and heating caused by a type of magnetic wave called ion cyclotron waves. Both, however, have some problem -- turbulence struggles to explain why Hydrogen, Helium and Oxygen in the gas become as hot as they do, while electrons remain surprisingly cold; while the magnetic waves theory could explain this feature, there doesn't seem to be enough of the waves coming off the Sun's surface to heat up the gas. The group used six-dimensional supercomputer simulations of the coronal gas to show how these two theories are actually part of the same process, linked together by a bizarre effect called the 'helicity barrier'. If we imagine plasma heating as occurring a bit like water flowing down a hill, with electrons heated right at the bottom, then the helicity barrier acts like a dam, stopping the flow and diverting its energy into ion cyclotron waves. In this way, the helicity barrier links the two theories and resolves each of their individual problems.
For this latest study, the group stirred the magnetic field lines in simulations and found the turbulence created the waves, which then caused the heating. As this happens, the structures and eddies that form end up looking extremely similar to cutting-edge measurements from NASA's Parker Solar Probe spacecraft, which has recently become the first human-made object to actually fly into the corona. This gives astronomer confidence that they are accurately capturing key physics in the corona, which -- coupled with the theoretical findings about the heating mechanisms -- is a promising path to understanding the coronal heating problem. Understanding more about the Sun's atmosphere and the subsequent solar wind is important because of the profound impacts they have on Earth. Effects which result from solar wind's interaction with the Earth's magnetic field is called 'space weather', which causes everything from Aurora to satellite-destroying radiation and geomagnetic currents which damage the power grid. All of this is sourced, fundamentally, by the corona and its heating by magnetic fields, so as well as being interesting for our general understanding of the solar system, the solar-corona's dynamics can have profound impacts on Earth.

MERCURY HAS MAGNETIC STORMS
University of Alaska Fairbanks

A team of scientists has proved that Mercury, our solar system's smallest planet, has geomagnetic storms similar to those on Earth. Their finding, a first, answers the question of whether other planets, including those outside our solar system, can have geomagnetic storms regardless of the size of their magnetosphere or whether they have an Earth-like ionosphere. The team proves the planet has a ring current, a doughnut-shaped field of charged particles flowing laterally around the planet and excluding the poles and also the existence of geomagnetic storms triggered by the ring current. A geomagnetic storm is a major disturbance in a planet's magnetosphere caused by the transfer of energy from the solar wind. Such storms in Earth's magnetosphere produce the aurora and can disrupt radio communications. Confirmation about geomagnetic storms on Mercury results from research made possible by a fortuitous coincidence: a series of coronal mass ejections from the Sun on April 8-18, 2015, and the end of NASA's Messenger space probe, which launched in 2004 and crashed into the planet's surface on April 30, 2015, at the expected end of its mission. A coronal mass ejection, or CME, is an ejected cloud of the sun's plasma -- a gas made of charged particles. That cloud includes the plasma's embedded magnetic field. The coronal mass ejection of April 14 proved to be the key for scientists. It compressed Mercury's ring current on the sun-facing side and increased the current's energy.
New analysis of data from Messenger, which had dropped closer to the planet, shows the presence of a ring current intensification that is essential for triggering magnetic storms. But this doesn't mean Mercury has auroral displays like those on Earth. On Earth, the storms produce aurora displays when solar wind particles interact with the particles of the atmosphere. On Mercury, however, solar wind particles don't encounter an atmosphere. Instead, they reach the surface unimpeded and may therefore be visible only through X-ray and gamma ray examination.The results show that magnetic storms are "potentially a common feature of magnetized planets. The results obtained from Messenger provide a further fascinating insight into Mercury's place in the evolution of the solar system following the discovery of its intrinsic planetary magnetic field.

SPEED OF SOUND ON MARS IS SLOWER THAN ON EARTH
NASA/JPL-Caltech

A team of scientists has revealed how fast sound travels through the extremely thin, mostly carbon dioxide atmosphere of Mars and how it might sound to human ears. Most of the sounds in the study were recorded using the microphone on Perseverance's SuperCam, mounted on the head of the rover's mast. The study also refers to sounds recorded by another microphone mounted on the chassis of the rover. This second microphone recently recorded the puffs and pings of the rover's Gaseous Dust Removal Tool, or gDRT, which blows shavings off rocks that the rover has scraped in order to examine. The result of the recordings reveal a new understanding of strange characteristics of the Martian atmosphere, where the speed of sound is slower than on Earth - and varies with pitch (or frequency). On Earth, sounds typically travel at 343 metres per second. But on Mars, low-pitched sounds travel at about 240 metres per second, while higher-pitched sounds move at 250 metres per second. The variable sound speeds on the Red Planet are an effect of the thin, cold, carbon dioxide atmosphere. Prior to the mission, scientists expected Mars' atmosphere would influence sound speed, but the phenomenon had never been observed until these recordings were made. Another effect of this thin atmosphere: Sounds carry only a short distance, and higher-pitched tones carry hardly at all. On Earth, sound might drop off after about 65 metres; on Mars, it falters at just 8 metres, with high-pitched sounds being lost completely at that distance. The recordings from SuperCam's microphone also reveal previously unobserved pressure variations produced by turbulence in the Martian atmosphere as its energy changes at tiny scales. Martian wind gusts at very short timescales also were measured for the first time. One of the most striking features of the sound recordings is the silence that seems to prevail on Mars. That, too, is a consequence of Mars having such a thin atmosphere. That means, in the Martian autumn months to come, Mars might get noisier - and provide even more insights into its otherworldly air and weather.

'PRENATAL' PROTOPLANET DISCOVERED
National Institutes of Natural Sciences

An international research team has discovered a new planet so young that it has yet to emerge from the womb of matter where it is forming. This is the youngest protoplanet discovered to date. It's location and the surrounding patterns of matter suggest that an alternative method of planet formation may be at work. This discovery could help to explain the histories and features of extrasolar planets seen around other stars. In the standard model of planet formation, a large Jupiter-like gas planet starts as a rocky core in a protoplanetary disk around a young star. This core then accretes gas from the disk, growing into a giant planet. While this model works well for the planets in the Solar System, it has trouble explaining exoplanets which have been discovered around other stars at distances much larger than the orbit of Neptune, the outermost Solar System planet. Rocky cores aren't expected to form far away from the central star, so core accretion can't drive distant planet formation. One theory holds that outlying planets form close to the central star and move outwards. But new observations using an extreme adaptive optics system which allows the Subaru Telescope to directly image faint objects close to brighter stars show what appears to be a protoplanet in the process of forming directly at a distance of 93 au: over three times the distance between the Sun and Neptune.
Analysis of this object, named AB Aur b, shows that a simple model of starlight reflected from an anomaly in the disk can't reproduce the observations; but neither can a model of a naked planet. The best fit models indicate that AB Aur b is a protoplanet so young that it is still forming in a womb of matter in the protoplanetary disk. Nearby spiral structures in the disk match models where a planet forms directly from the gravitational collapse of the surrounding matter. This discovery has profound implications for explaining the many observed outlying exoplanets and the overall theoretical model of planet formation.
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CASSIOPEIA  A SUPERNOVA EJECTION NEBULA
Netherlands Research School for Astronomy

Cassiopeia A is the remnant of an exploded star in the Cassiopeia constellation, about 11,000 light years away from us. Light from the explosion should have reached Earth for the first time around 1670. However, there was too much gas and dust around the star for the explosion to be seen with the naked eye or with the then very basic telescopes. The Cassiopeia A explosion nebula is expanding at an average rate of 4,000 to 6,000 kilometres per second and has a temperature of about 30 million degrees Celsius. The expansion is most likely occurring in gas that was blown out by the star long before the explosion. Cassiopeia A is now about 16 light years across. The researchers analysed 19 years of data from the Chandra X-ray Observatory that orbits the Earth in a high elliptical orbit. The scientists observed that on the western side of Cassiopeia A, the inner regions of the explosion nebula are not expanding, but moving inwards. The researchers also took measurements of the acceleration or deceleration of the outer shock wave. This outer shock wave turned out to accelerate in the west instead of decelerating as was expected. The backward movement in the west can mean two things. Either there is a hole somewhere, a kind of vacuum, in the supernova material, causing the hot shell to suddenly move inwards locally. Or the nebula has collided with something. From the computer models, a collision appears most likely. They predict that after a collision, the shock first decreases in speed but then accelerates. Exactly as the team has measured.

MYSTERIOUS DEATH THROES OF CARBON STAR
National Radio Astronomy Observatory

Scientists studying V Hydrae (V Hya) have witnessed the star's mysterious death throes in unprecedented detail. Using the Atacama Large Millimeter/submillimeter Array (ALMA) and data from the Hubble Space Telescope (HST), the team discovered six slowly-expanding rings and two hourglass-shaped structures caused by the high-speed ejection of matter out into space. V Hya is a carbon-rich asymptotic giant branch (AGB) star located approximately 1,300 light-years from Earth in the constellation Hydra. More than 90-percent of stars with a mass equal to or greater than the Sun evolve into AGB stars as the fuel required to power nuclear processes is stripped away. Among these millions of stars, V Hya has been of particular interest to scientists due to its so-far unique behaviours and features, including extreme-scale plasma eruptions that happen roughly every 8.5 years and the presence of a nearly invisible companion star that contributes to V Hya's explosive behaviour. The six rings have expanded outward from V Hya over the course of roughly 2,100 years, adding matter to and driving the growth of a high-density flared and warped disk-like structure around the star. The team has dubbed this structure the DUDE, or Disk Undergoing Dynamical Expansion. V Hya is in the brief but critical transition phase that does not last very long, and it is difficult to find stars in this phase. In addition to a full set of expanding rings and a warped disk, V Hya's final act features two hourglass-shaped structures -- and an additional jet-like structure -- that are expanding at high speeds of more than half a million miles per hour (240 km/s). Large hourglass structures have been observed previously in planetary nebulae, including MyCn 18 -- also known as the Engraved Hourglass Nebula -- a young emission nebula located roughly 8,000 light-years from Earth in the southern constellation of Musca, and the more well-known Southern Crab Nebula, an emission nebula located roughly 7,000 light-years from Earth in the southern constellation Centaurus. Scientists first observed the presence of very fast outflows in 1981. Then, in 2022, they found a jet-like flow consisting of compact plasma blobs ejected at high speeds from V Hya. And now, the discovery of wide-angle outflows in V Hya connects the dots, revealing how all these structures can be created during the evolutionary phase that this extra-luminous red giant star is now in.

HUBBLE SPOTS FARTHEST STAR EVER SEEN
NASA/Goddard Space Flight Center

The Hubble Space Telescope has established an extraordinary new benchmark: detecting the light of a star that existed within the first billion years after the Universe's birth in the big bang -- the farthest individual star ever seen to date. The find is a huge leap further back in time from the previous single-star record holder; detected by Hubble in 2018. That star existed when the Universe was about 4 billion years old, or 30 percent of its current age, at a time that astronomers refer to as "redshift 1.5." Scientists use the word "redshift" because as the Universe expands, light from distant objects is stretched or "shifted" to longer, redder wavelengths as it travels toward us. The newly detected star is so far away that its light has taken 12.9 billion years to reach Earth, appearing to us as it did when the Universe was only 7 percent of its current age, at redshift 6.2. The smallest objects previously seen at such a great distance are clusters of stars, embedded inside early galaxies. Normally at these distances, entire galaxies look like small smudges, with the light from millions of stars blending together. The galaxy hosting this star has been magnified and distorted by gravitational lensing into a long crescent that has been named the Sunrise Arc. After studying the galaxy in detail, astronomers determined that one feature is an extremely magnified star that they called Earendel, which means "morning star" in Old English. The discovery holds promise for opening up an uncharted era of very early star formation. It will be a window into an era of the Universe that we are unfamiliar with, but that led to everything we do know.
The research team estimates that Earendel is at least 50 times the mass of our Sun and millions of times as bright, rivalling the most massive stars known. But even such a brilliant, very high-mass star would be impossible to see at such a great distance without the aid of natural magnification by a huge galaxy cluster, WHL0137-08, sitting between us and Earendel. The mass of the galaxy cluster warps the fabric of space, creating a powerful natural magnifying glass that distorts and greatly amplifies the light from distant objects behind it. Thanks to the rare alignment with the magnifying galaxy cluster, the star Earendel appears directly on, or extremely close to, a ripple in the fabric of space. This ripple, which is defined in optics as a "caustic," provides maximum magnification and brightening. The effect is analogous to the rippled surface of a swimming pool creating patterns of bright light on the bottom of the pool on a sunny day. The ripples on the surface act as lenses and focus sunlight to maximum brightness on the pool floor. This caustic causes the star Earendel to pop out from the general glow of its home galaxy. Its brightness is magnified a thousandfold or more. At this point, astronomers are not able to determine if Earendel is a binary star, though most massive stars have at least one smaller companion star. Astronomers expect that Earendel will remain highly magnified for years to come. It will be observed by NASA's James Webb Space Telescope. Webb's high sensitivity to infrared light is needed to learn more about Earendel, because its light is stretched (redshifted) to longer infrared wavelengths due to the Universe's expansion.

SCIENTISTS DISCOVER FARTHEST GALAXY EVER
RAS

Astronomers have discovered the most distant astronomical object ever: a galaxy 13.5 billion light years away. Named HD1, scientists have begun to speculate exactly what it is. Shining only ~300 million years after the Big Bang, it may be home to the oldest stars in the Universe, or a supermassive black hole. HD1 was discovered after more than 1,200 hours of observing time with the Subaru Telescope, VISTA Telescope, UK Infrared Telescope and Spitzer Space Telescope. The team then conducted follow-up observations using the Atacama Large Millimetre/submillimetre Array (ALMA) to confirm the distance, which is 100 million light years further than GN-z11, the current record-holder for the furthest galaxy.  The team proposes two ideas: HD1 may be forming stars at an astounding rate and is possibly even home to the Universe's very first stars, known as Population III stars -- which, until now, have never been observed. Alternatively, HD1 may contain a supermassive black hole about 100 million times the mass of our Sun. 
The very first population of stars that formed in the Universe were more massive, more luminous and hotter than modern stars. If we assume the stars produced in HD1 are these first, or Population III, stars, then its properties could be explained more easily. In fact, Population III stars are capable of producing more UV light than normal stars, which could clarify the extreme ultraviolet luminosity of HD1. Answering questions about the nature of a source so far away can be challenging. It's like guessing the nationality of a ship from the flag it flies, while being faraway ashore, with the vessel in the middle of a gale and dense fog. One can maybe see some colours and shapes of the flag, but not in their entirety. It's ultimately a long game of analysis and exclusion of implausible scenarios. Forming a few hundred million years after the Big Bang, a black hole in HD1 must have grown out of a massive seed at an unprecedented rate. Using the James Webb Space Telescope, the research team will soon once again observe HD1 to verify its distance from Earth. If current calculations are right, HD1 will be the most distant -- and oldest -- galaxy ever recorded. The same observations will allow the team to dig deeper into HD1's identity and confirm if one of their theories is correct.

MOST DETAILED MODEL OF EARLY UNIVERSE TO DATE
Massachusetts Institute of Technology

It all started around 13.8 billion years ago with a big, cosmological "bang" that brought the Universe suddenly and spectacularly into existence. Shortly after, the infant Universe cooled dramatically and went completely dark. Then, within a couple hundred million years after the Big Bang, the Universe woke up, as gravity gathered matter into the first stars and galaxies. Light from these first stars turned the surrounding gas into a hot, ionized plasma -- a crucial transformation known as cosmic reionization that propelled the Universe into the complex structure that we see today. Now, scientists can get a detailed view of how the Universe may have unfolded during this pivotal period with a new simulation, known as Thesan, developed by scientists at MIT, Harvard University, and the Max Planck Institute for Astrophysics. Named after the Etruscan goddess of the dawn, Thesan is designed to simulate the "cosmic dawn," and specifically cosmic reionization, a period which has been challenging to reconstruct, as it involves immensely complicated, chaotic interactions, including those between gravity, gas, and radiation. The Thesan simulation resolves these interactions with the highest detail and over the largest volume of any previous simulation. It does so by combining a realistic model of galaxy formation with a new algorithm that tracks how light interacts with gas, along with a model for cosmic dust. With Thesan, the researchers can simulate a cubic volume of the Universe spanning 300 million light years across. They run the simulation forward in time to track the first appearance and evolution of hundreds of thousands of galaxies within this space, beginning around 400,000 years after the Big Bang, and through the first billion years.
So far, the simulations align with what few observations astronomers have of the early Universe. As more observations are made of this period, for instance with the newly launched James Webb Space Telescope, Thesan may help to place such observations in cosmic context. For now, the simulations are starting to shed light on certain processes, such as how far light can travel in the early Universe, and which galaxies were responsible for reionization. In the earliest stages of cosmic reionization, the Universe was a dark and homogenous space. For physicists, the cosmic evolution during these early "dark ages" is relatively simple to calculate. To fully simulate cosmic reionization, the team sought to include as many major ingredients of the early Universe as possible. They started off with a successful model of galaxy formation that their groups previously developed, called Illustris-TNG, which has been shown to accurately simulate the properties and populations of evolving galaxies. They then developed a new code to incorporate how the light from galaxies and stars interact with and reionize the surrounding gas -- an extremely complex process that other simulations have not been able to accurately reproduce at large scale. Finally, the team included a preliminary model of cosmic dust -- another feature that is unique to such simulations of the early universe. This early model aims to describe how tiny grains of material influence the formation of galaxies in the early, sparse Universe. With the simulation's ingredients in place, the team set its initial conditions for around 400,000 years after the Big Bang, based on precision measurements of relic light from the Big Bang. They then evolved these conditions forward in time to simulate a patch of the Universe, using the SuperMUC-NG machine -- one of the largest supercomputers in the world -- which simultaneously harnessed 60,000 computing cores to carry out Thesan's calculations over an equivalent of 30 million CPU hours (an effort that would have taken 3,500 years to run on a single desktop). The simulations have produced the most detailed view of cosmic reionization, across the largest volume of space, of any existing simulation. While some simulations model across large distances, they do so at relatively low resolution, while other, more detailed simulations do not span large volumes. Early analyses of the simulations suggest that towards the end of cosmic reionization, the distance light was able to travel increased more dramatically than scientists had previously assumed. The researchers also see hints of the type of galaxies responsible for driving reionization. A galaxy's mass appears to influence reionization, though the team says more observations, taken by James Webb and other observatories, will help to pin down these predominant galaxies.

Bulletin compiled by Clive Down
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Astronomy / The night sky in April 2022
April 03, 2022, 05:11:16 pm
THE NIGHT SKY IN APRIL 2022
As April arrives, the brilliant constellations Taurus, Orion, and Canis Major turn to the west after sunset and are on their way out for the year. Mercury makes an appearance in the second half of the month in the evening sky and encounters the Pleiades as April winds down. The Lyrid meteors arrive, the first major meteor shower since January. And planets begin to congregate in the morning sky leading to a number of spectacularly close conjunctions for observers with or without optics. Here's what to see in the night sky this month...

CLICK HERE
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Music / MA BESSIE & HER PIG FOOT BAND
April 01, 2022, 10:56:35 am
MA BESSIE & HER PIG FOOT BAND
Rhosygilwen 16th April
Julia Titus formed her Pig Foot Band in mid-2015 to share the music of Bessie Smith and her contemporaries, with a new generation of listeners. Mixing Julia's rich, warm vocal sound with a dynamic band that look and sound the part, Ma Bessie & her Pig Foot Band perform classic blues and jazz tunes from the inter-war years with a selection of original songs and hand-picked covers from the last 50 years of popular music.  The Ma Bessie repertoire includes classics such as 'Careless Love', 'Nobody Knows When You're Down And Out' and, of course, 'Gimme A Pig Foot (And A Bottle Of Beer)

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Astronomy / Preselli Astronomy Group Needs YOU!
March 28, 2022, 11:42:13 am
Important Meeting: 7.00pm Tuesday 5th April in Letterston Community Hall   
   
The Preseli Astronomy Group has been meeting monthly at Letterston Community Hall for a number of years. The group has assembled a fine collection of telescopes and other astronomical equipment, and in the past has participated in many local Citizen Science events, especially its annual Summer Solar observing for the public at Newgale.

The Covid pandemic has devastated the Preseli Astronomy Group's activities, so it has been decided to restart the group from scratch. There will be a meeting in Letterston Village Hall at 19.00 on Tuesday 5th April to assess the future of the Preseli Astronomy Group and elect a new committee.

Sadly, if there is not enough interest the group will be dissolved and its assets and equipment will be offered to other astronomy clubs. This would be a sad loss for Pembrokeshire as West Wales has such wonderful opportunities for observing the night sky and the Preseli Astronomy Group has encouraged many to take up the hobby over the years.
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General Chatty Stuff / This made me chuckle!
March 27, 2022, 07:35:37 pm
Love this from Narberth (Pembrokeshire)  U3A weekly newsletter.
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Fun Run - or not?
Last week we had an invitation from a Narberth charity to send a team to their fun run.  It sounded tempting but might have stretched your resources, as it came from Narberth Pennsylvania! The organiser had a good laugh and said she'd had a long week."