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Messages - Geoffw

General Chatty Stuff / Fancy buying a house here?
September 24, 2021, 11:37:48 am
Guatemalan Sinkhole

In 2010, the Guatemala City was hit by the tropical storm called Agatha and this horrifying sinkhole appeared.

The sinkhole's diameter was about 65 feet with the depth being around 300 feet. This looks really scary and what's even scarier is that sinkholes are a frequent occurrence in Guatemala City.
An unacceptable state of a affairs that pre-dates Covid. 

I had a front seat view of the chaos on Saturday morning.  I pull in to the Ridgeway Garage on the Fishguard Road.  By the door of the garage an elderly gentleman had collapsed and was laying prone on the concrete being comforted by staff and customers.  Inside I found the manageress distraught.  She had rung for an ambulance to be told none were available!

All this happening of the edge of our County Town and less than a mile from a General Hospital with an A&E department!
Astronomy Group / Preseli Astronomy Group meeting Again
September 23, 2021, 06:26:22 pm
Preseli Astronomy Group
Meet: 1st Tuesday of the montha at 7.00pm
Venue: Letterston Memornial Hall, Station Rd, Letterston, Haverfordwest SA62 5RY

We will be holding our first post covid meeting on Tuesday 5 October at 19.00  as restrictions are still in place we hope to be having an observing session in the car park. If the weather is unfavourable there will be a display of telescopes indoors along with an introduction to amateur astronomy.

This will be a free event and all are welcome to come along, but donations to the group are always welcome, you may bring  your own equipment or borrow the group's scopes.

We will not be asking for any membership subscriptions until we can get the group up and running properly, with regular monthly meetings and a sufficient number of interested people to cover the group's annual costs.
Covid restrictions still apply at Letterston Village Hall, the kitchen facilities are currently closed so sorry no tea or coffee available and face masks must be worn inside the building, hand sanitizer is available on site.
THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 550 2021 Sep 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.


NASA's Perseverance rover has completed the collection of the first sample of Martian rock, a core from Jezero Crater slightly thicker than a pencil. The core is now enclosed in an airtight titanium sample tube, making it available for retrieval in the future. Through the Mars Sample Return campaign, NASA and ESA (European Space Agency) are planning a series of future missions to return the rover's sample tubes to Earth for closer study. These samples would be the first set of scientifically identified and selected materials returned to our planet from another. Along with identifying and collecting samples of rock and regolith (broken rock and dust) while searching for signs of ancient microscopic life, Perseverance's mission includes studying the Jezero region to understand the geology and ancient habitability of the area, as well as to characterize the past climate.


On Aug. 14, a small near-Earth asteroid (NEA) designated 2021 PJ1 passed our planet at a distance of 1.7 million kilometres. Between 20 and 30 metres wide, the recently discovered asteroid wasn't a threat to Earth. But this asteroid's approach was historic, marking the 1,000th NEA to be observed by planetary radar in just over 50 years. And only seven days later, planetary radar observed the 1,001st such object, but this one was much larger. Since the first radar observation of the asteroid 1566 Icarus in 1968, this powerful technique has been used to observe passing NEAs and comets (collectively known as near-Earth objects, or NEOs). These radar detections improve our knowledge of NEO orbits, providing the data that can extend calculations of future motion by decades to centuries and help definitively predict if an asteroid is going to hit Earth, or if it's just going to pass close by. For example, recent radar measurements of the potentially hazardous asteroid Apophis helped eliminate any possibility of it impacting Earth for the next 100 years. In addition, they can provide scientists with detailed information on physical properties that could be matched only by sending a spacecraft and observing these objects up close. Depending on an asteroid's size and distance, radar can be used to image its surface in intricate detail while also determining its size, shape, spin rate, and whether or not it is accompanied by one or more small moons. In the case of 2021 PJ1, the asteroid was too small and the observing time too short to acquire images. But as the 1,000th NEA detected by planetary radar, the milestone highlights the efforts to study the NEAs that have passed close to Earth.

University of Georgia

The asteroid Vesta is the second largest asteroid in our solar system. With a diameter of about 330 miles, it orbits the Sun between the planets Mars and Jupiter. Asteroids have long played a part in building popular fascination with space. "Marooned off Vesta" was the first story published by American writer Isaac Asimov, the third story he wrote, appearing in the March 1939 issue of the science fiction magazine Amazing Stories. Vesta, like Earth, is composed of rock in its crust and mantle, and it has an iron core. Because of its large size (for an asteroid) and because Vesta has a crust, mantle and core, it is considered a planetesimal. Planetesimals are building blocks out of which planets form. Earth formed by accretion of several such planetesimals. "Vesta was on the way to becoming an Earth-like planet, too, but planet formation stopped along the way there early in the history of our solar system. Vesta was hit by two other large asteroids which left large impact craters so big they cover most of the southern hemisphere of Vesta. These impacts are thought to have ejected rocky material into space. Some of these rocks reached Earth as meteorites so scientists now have actual rock samples from Vesta to study its geochemistry. One big question is what triggered the formation of these large troughs. The two troughs are concentric around the two massive impact basins, Rheasilvia and Veneneia, respectively, and widely considered to be simultaneously formed by the impact events, though this assumed age relationship has never been tested before. The origin of the troughs has long been a point of conjecture within the scientific community.

The leading hypothesis suggests that these troughs are fault-bounded valleys with a distinct scarp on each side that together mark the down-drop (sliding) of a block of rock. However, rock can also crack apart and form such troughs, an origin that has not been considered before. Calculations also show that Vesta's gravity is not enough to induce surrounding stresses favourable for sliding to occur at shallow depths, instead, the physics shows that rocks there are favoured to crack apart. Therefore, the formation of these troughs must involve the opening of cracks, which is inconsistent with the leading hypothesis in the scientific community. Taken all together, the overall project provides alternatives to the previously proposed trough origin and geological history of Vesta, results that are also important for understanding similar landforms on other small planetary bodies elsewhere in the solar system.


On the night of September 13-14, German astronomer Harald Paleske was watching the shadow of Io create a solar eclipse in the atmosphere of Jupiter when something unexpected happened. "A bright flash of light surprised me," he says. "It could only be an impact." Paleske video-recorded the event. Reviewing the frames, he quickly ruled out objects such as airplanes and satellites, which might be crossing Jupiter at the time of his observation. The fireball was fixed in Jupiter's atmosphere. It first appeared at 22:39:27 UT on Sept. 13th and remained visible for a full two seconds. The most likely explanation is a small asteroid or comet striking the giant planet; an asteroid in the 100m size range would do the trick. This isn't the first time astronomers have seen things hitting Jupiter. The most famous example is Comet Shoemaker-Levy 9 (SL9), which struck Jupiter in July 1994. At the time, most astronomers thought such collisions were rare, happening every hundred years or so. Since SL9, however, amateur astronomers using improved low-light cameras have observed more than a dozen impact flashes in Jupiter's cloudtops. The Solar System is more dangerous than we thought. Paleske pinpoints the fireball at Jovian latitude 106.9° (CM1), longitude +3.8°. Other observers are encouraged to monitor the location for debris. Previous impacts have sometimes created inky clouds -- probably the remains of the impactor itself mixed with aerosols formed by shock-chemistry during the explosion.

Cosmos Up

Stars have always been part of civilizations. In Ancient Times, we relied upon the apparent motion of these bodies to navigate distances, to measure the passage of time therefore determining seasons, months, and years. Simply, stars are the very reason we exist. We are literally made up of "stardust". A star, by definition, is an astronomical object consisting mostly of hydrogen and helium all held together by its own gravity. Stars are the most fundamental building blocks of galaxies. So, how many stars are in the Milky Way? Clearly, it is impossible to know exactly how many stars are out there, in all variety of masses and sizes, astronomers estimate that our galaxy alone is made up of approximately 100 billion stars. The most common stars are Red dwarf, which make up the largest population of stars in our galaxy. On the other side of the spectrum are hypergiants, the biggest known stars in the Universe. Since the Gaia data release, scientists have adjusted the distances and therefore the mass of many stars. Prior to the Gaia release, UY Scuti was considered the biggest of these stars, around 1,700 times the Sun's width. Now, we have a new heavyweight champion, an object that defy expectations. Meet Stephenson 2-18.

Stephenson 2-18 is a red supergiant located 19,800 light years away from us in a relatively small cluster called Stephenson 2 in the constellation of Scutum. With an estimated radius about 2,100 times that of the Sun, and a volume nearly 10 billion times of our Sun, Stephenson 2-18 is mind-boggling big, it appears to be considerably larger than the maximum theoretical size of a hypergiant. To put it in perspective, if the centre of our solar system were replaced by Stephenson 2-18, the star's outer atmospheric layer would extend beyond the orbit of Saturn. It would take Earth's fastest plane more than 500 years to travel around. Astronomers predict that Stephenson 2-18 may even continue to grow bigger, possibly one day becoming what is known as a yellow hyper-giant. Just a few million years from now this gigantic glowing ball of plasma may also enter into the latter stages of its life as it quickly burns through its fuel and eventually explodes in a catastrophic, but magnificent supernova, possibly even leaving behind a black hole as a reminder of Stephenson 2-18s once extreme parameters.

Osaka University

Although thousands of planets have been discovered in the Milky Way, most reside less than a few thousand light years from Earth. Yet our Galaxy is more than 100,000 light years across, making it difficult to investigate the Galactic distribution of planets. But now, a research team has found a way to overcome this hurdle. Scientists have used a combination of observations and modelling to determine how the planet-hosting probability varies with the distance from the Galactic centre. The observations were based on a phenomenon called gravitational microlensing, whereby objects such as planets act as lenses, bending and magnifying the light from distant stars. This effect can be used to detect cold planets similar to Jupiter and Neptune throughout the Milky Way, from the Galactic disk to the Galactic bulge -- the central region of our Galaxy. Gravitational microlensing currently provides the only way to investigate the distribution of planets in the Milky Way, but until now, little is known mainly because of the difficulty in measuring the distance to planets that are more than 10,000 light years from the Sun. To solve this problem, the researchers instead considered the distribution of a quantity that describes the relative motion of the lens and distant light source in planetary microlensing. By comparing the distribution observed in microlensing events with that predicted by a Galactic model, the research team could infer the Galactic distribution of planets. The results show that the planetary distribution is not strongly dependent on the distance from the Galactic centre. Instead, cold planets orbiting far from their stars seem to exist universally in the Milky Way. This includes the Galactic bulge, which has a very different environment to the solar neighbourhood, and where the presence of planets has long been uncertain.

ESA/Hubble Information Centre

The prevalent view of white dwarfs as inert, slowly cooling stars has been challenged by observations from the Hubble Space Telescope. White dwarfs are the slowly cooling stars which have cast off their outer layers during the last stages of their lives. They are common objects in the cosmos; roughly 98% of all the stars in the Universe will ultimately end up as white dwarfs, including our own Sun. Studying these cooling stages helps astronomers understand not only white dwarfs, but also their earlier stages as well. To investigate the physics underpinning white dwarf evolution, astronomers compared cooling white dwarfs in two massive collections of stars: the globular clusters M3 and M13. These two clusters share many physical properties such as age and metallicity but the populations of stars which will eventually give rise to white dwarfs are different. In particular, the overall colour of stars at an evolutionary stage known as the Horizontal Branch are bluer in M13, indicating a population of hotter stars. This makes M3 and M13 together a perfect natural laboratory in which to test how different populations of white dwarfs cool. Using Hubble's Wide Field Camera 3 the team observed M3 and M13 at near-ultraviolet wavelengths, allowing them to compare more than 700 white dwarfs in the two clusters. They found that M3 contains standard white dwarfs which are simply cooling stellar cores. M13, on the other hand, contains two populations of white dwarfs: standard white dwarfs and those which have managed to hold on to an outer envelope of hydrogen, allowing them to burn for longer and hence cool more slowly.

Comparing their results with computer simulations of stellar evolution in M13, the researchers were able to show that roughly 70% of the white dwarfs in M13 are burning hydrogen on their surfaces, slowing down the rate at which they are cooling. This discovery could have consequences for how astronomers measure the ages of stars in the Milky Way. The evolution of white dwarfs has previously been modelled as a predictable cooling process. This relatively straightforward relationship between age and temperature has led astronomers to use the white dwarf cooling rate as a natural clock to determine the ages of star clusters, particularly globular and open clusters. However, white dwarfs burning hydrogen could cause these age estimates to be inaccurate by as much as 1 billion years.

National Radio Astronomy Observatory

Astronomers have found dramatic evidence that a black hole or neutron star spiralled its way into the core of a companion star and caused that companion to explode as a supernova. The astronomers were tipped off by data from the Very Large Array Sky Survey (VLASS), a multi-year project using the National Science Foundation's Karl G. Jansky Very Large Array (VLA). The first clue came when the scientists examined images from VLASS, which began observations in 2017, and found an object brightly emitting radio waves but which had not appeared in an earlier VLA sky survey, called Faint Images of the Radio Sky at Twenty centimeters (FIRST). They made subsequent observations of the object, designated VT 1210+4956, using the VLA and the Keck telescope in Hawaii. They determined that the bright radio emission was coming from the outskirts of a dwarf, star-forming galaxy some 480 million light-years from Earth. They later found that an instrument aboard the International Space Station had detected a burst of X-rays coming from the object in 2014. The data from all these observations allowed the astronomers to piece together the fascinating history of a centuries-long death dance between two massive stars. Like most stars that are much more massive than our Sun, these two were born as a binary pair, closely orbiting each other. One of them was more massive than the other and evolved through its normal, nuclear fusion-powered lifetime more quickly and exploded as a supernova, leaving behind either a black hole or a superdense neutron star. The black hole or neutron star's orbit grew steadily closer to its companion, and about 300 years ago it entered the companion's atmosphere, starting the death dance. At this point, the interaction began spraying gas away from the companion into space. The ejected gas, spiralling outward, formed an expanding, donut-shaped ring, called a torus, around the pair.

Eventually, the black hole or neutron star made its way inward to the companion star's core, disrupting the nuclear fusion producing the energy that kept the core from collapsing of its own gravity. As the core collapsed, it briefly formed a disk of material closely orbiting the intruder and propelled a jet of material outward from the disk at speeds approaching that of light, drilling its way through the star. The collapse of the star's core caused it to explode as a supernova, following its sibling's earlier explosion. The material ejected by the 2014 supernova explosion moved much faster than the material thrown off earlier from the companion star, and by the time VLASS observed the object, the supernova blast was colliding with that material, causing powerful shocks that produced the bright radio emission seen by the VLA. The key to the discovery, Hallinan said, was VLASS, which is imaging the entire sky visible at the VLA's latitude -- about 80 percent of the sky -- three times over seven years. One of the objectives of doing VLASS that way is to discover transient objects, such as supernova explosions, that emit brightly at radio wavelengths. This supernova, caused by a stellar merger, however, was a surprise.

University of Copenhagen - Faculty of Science

An enormous amount of gravity from a cluster of distant galaxies causes space to curve so much that light from them is bent and emanated our way from numerous directions. This "gravitational lensing" effect has allowed astronomers to observe the same exploding star in three different places in the heavens. They predict that a fourth image of the same explosion will appear in the sky by 2037. The study provides a unique opportunity to explore not just the supernova itself, but the expansion of our Universe. One of the most fascinating aspects of Einstein's theory of relativity is that gravity is no longer described as a force, but as a "curvature" of space itself. The curvature of space caused by heavy objects does not just cause planets to spin around stars, but can also bend the orbit of light beams. The heaviest of all structures in the Universe -- galaxy clusters made up of hundreds or thousands of galaxies -- can bend light from distant galaxies behind them so much that they appear to be in a completely different place than they actually are. But that's not it: light can take several paths around a galaxy cluster, making it possible for us to get lucky and make two or more sightings of the same galaxy in different places in the sky using a powerful telescope. Some routes around a galaxy cluster are longer than others, and therefore take more time. The slower the route, the stronger the gravity; yet another astonishing consequence of relativity. This staggers the amount of time needed for light to reach us, and thereby the different images that we see. This has allowed a team of astronomers at the Cosmic Dawn Center -- a basic research center run by the Niels Bohr Institute at the University of Copenhagen and DTU Space at the Technical University of Denmark to observe a single galaxy in no less than four different places in the sky. The observations were made using the infrared wavelength range of the Hubble Space Telescope.

By analyzing the Hubble data, researchers noted three bright light sources in a background galaxy that were evident in a previous set of observations from 2016, which disappeared when Hubble revisited the area in 2019. These three sources turned out to be several images of a single star whose life ended in a colossal explosion known as a supernova. The supernova, nicknamed "SN-Requiem," can be seen in three of the four "mirrored images" of the galaxy. Each image presents a different view of the explosive supernova's development. In the final two images, it has not yet exploded. But, by examining how galaxies are distributed within the galaxy cluster and how these images are distorted by curved space, it is actually possible to calculate how "delayed" these images are. This has allowed astronomers to make a remarkable The fourth image of the galaxy is roughly 21 years behind, which should allow us to see the supernova explode one more time, sometime around 2037. Should we get to witness the SN-Requiem explosion again in 2037, it will not only confirm our understanding of gravity, but also help to shed light on another cosmological riddle that has emerged in the last few years, namely the expansion of our Universe. We know that the Universe is expanding, and that different methods allow us to measure by how fast. The problem is that the various measurement methods do not all produce the same result, even when measurement uncertainties are taken into account. Could our observational techniques be flawed, or -- more interestingly -- will we need to revise our understandings of fundamental physics and cosmology? Dark matter and dark energy are the mysterious matter believed to make up 95% of our Universe, whereas we can only see 5%. The perspectives of gravitational lenses are promising!

National Institutes of Natural Sciences

Forget about online games that promise you a "whole world" to explore. An international team of researchers has generated an entire virtual UNIVERSE, and made it freely available on the cloud to everyone. Uchuu (meaning "Outer Space" in Japanese) is the largest and most realistic simulation of the Universe to date. The Uchuu simulation consists of 2.1 trillion particles in a computational cube an unprecedented 9.63 billion light-years to a side. For comparison, that's about three-quarters the distance between Earth and the most distant observed galaxies. Uchuu will allow us to study the evolution of the Universe on a level of both size and detail inconceivable until now. Uchuu focuses on the large-scale structure of the Universe: mysterious halos of dark matter which control not only the formation of galaxies, but also the fate of the entire Universe itself. The scale of these structures ranges from the largest galaxy clusters down to the smallest galaxies. Individual stars and planets aren't resolved, so don't expect to find any alien civilizations in Uchuu. But one way that Uchuu wins big in comparison to other virtual worlds is the time domain; Uchuu simulates the evolution of matter over almost the entire 13.8 billion year history of the Universe from the Big Bang to the present. That is over 30 times longer than the time since animal life first crawled out of the seas on Earth.

An international team of researchers from Japan, Spain, U.S.A., Argentina, Australia, Chile, France, and Italy created Uchuu using ATERUI II, the world's most powerful supercomputer dedicated to astronomy. Even with all this power, it still took a year to produce Uchuu. To produce Uchuu researchers used all 40,200 processors (CPU cores) available exclusively for 48 hours each month. Twenty million supercomputer hours were consumed, and 3 Petabytes of data were generated, the equivalent of 894,784,853 pictures from a 12-megapixel cell phone. The research team used high-performance computational techniques to compress information on the formation and evolution of dark matter haloes in the Uchuu simulation into a 100-terabyte catalogue. This catalogue is now available to everyone on the cloud in an easy to use format thanks to the computational infrastructure skun6 located at the Instituto de Astrofísica de Andalucía (IAA-CSIC), the RedIRIS group, and the Galician Supercomputing Center (CESGA). Future data releases will include catalogues of virtual galaxies and gravitational lensing maps. Big Data science products from Uchuu will help astronomers learn how to interpret Big Data galaxy surveys expected in coming years from facilities like the Subaru Telescope and the ESA Euclid space mission.

Bulletin compiled by Clive Down
(c) 2021 The Society for Popular Astronomy
The Society for Popular Astronomy has been helping beginners in amateur astronomy -- and more experienced observers -- for over 60 years. If you are not a member, you may be missing something. Membership rates are extremely reasonable, starting at just £23 a year in the UK. You will receive our bright bi-monthly magazine Popular Astronomy, help and advice in pursuing your hobby, the chance to hear top astronomers at our regular meetings, and other benefits. The best news is that you can join online right now with a credit or debit card at our lively website: www.popastro.com

Family History / Lost Cousin's News
September 13, 2021, 07:54:06 am
We can't bring our ancestors back, but we can keep the memory of them alive....

Plan to map churchyards causes confusion
Conditional baptism
A 19th century midwife
What do you call a male midwife?
Mix-up at the hospital
The other Cromwell
Preserving family heirlooms
Mr & Mrs Selfridge
A medieval place of sanctuary
The Prisoner EXCLUSIVE
The Village
Review: Our Village Ancestors
Peter's Tips

To proceed to the newsletter click the link below (or else, highlight it, copy it, then paste it into your browser).

THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 549 2021 Sept 5


After successful completion of its final tests, NASA's James Webb Space Telescope is being prepped for shipment to its launch site. Engineering teams have completed Webb's long-spanning comprehensive testing regimen at Northrop Grumman's facilities. Webb's many tests and checkpoints were designed to ensure that the world's most complex space science observatory will operate as designed once in space. Now that observatory testing has concluded, shipment operations have begun. This includes all the necessary steps to prepare Webb for a safe journey through the Panama Canal to its launch location in Kourou, French Guiana, on the northeastern coast of South America. Since no more large-scale testing is required, Webb's clean room technicians have shifted their focus from demonstrating it can survive the harsh conditions of launch and work in orbit, to making sure it will safely arrive at the launch pad. Webb's contamination control technicians, transport engineers, and logistics task forces are all expertly prepared to handle the unique task of getting Webb to the launch site. Shipping preparations will be completed in September. While shipment operations are underway, teams at the Space Telescope Science Institute (STScI) in Baltimore will continue to check and recheck the complex communications network it will use in space. Recently this network fully demonstrated that it is capable of seamlessly sending commands to the spacecraft.

Once Webb arrives in French Guiana, launch processing teams will configure the observatory for flight. This involves post-shipment checkouts to ensure the observatory hasn't been damaged during transport, carefully loading the spacecraft's propellant tanks with hydrazine fuel and nitrogen tetroxide oxidizer it will need to power its rocket thrusters to maintain its orbit, and detaching 'remove before flight' red-tag items like protective covers that keep important components safe during assembly, testing, and transport. Then engineering teams will mate the observatory to its launch vehicle, an Ariane 5 rocket provided by ESA (European Space Agency), before it rolls out to the launch pad. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency. After launch, Webb will undergo a six-month commissioning period. Moments after completing a 26-minute ride aboard the Ariane 5 launch vehicle, the spacecraft will separate from the rocket and its solar array will deploy automatically. After that, all subsequent deployments over the next few weeks will be initiated from ground control located at STScI. Webb will take one month to fly to its intended orbital location in space nearly one million miles away from Earth, slowly unfolding as it goes. Sunshield deployments will begin a few days after launch, and each step can be controlled expertly from the ground, giving Webb's launch full control to circumnavigate any unforeseen issues with deployment. Once the sunshield starts to deploy, the telescope and instruments will enter shade and start to cool over time. Over the ensuing weeks, the mission team will closely monitor the observatory's cooldown, managing it with heaters to control stresses on instruments and structures. In the meantime, the secondary mirror tripod will unfold, the primary mirror will unfold, Webb's instruments will slowly power up, and thruster firings will insert the observatory into a prescribed orbit. Once the observatory has cooled down and stabilized at its frigid operating temperature, several months of alignments to its optics and calibrations of its scientific instruments will occur. Scientific operations are expected to com/mence approximately six months after launch.

University of California - Los Angeles

Sending human travellers to Mars would require scientists and engineers to overcome a range of technological and safety obstacles. One of them is the grave risk posed by particle radiation from the Sun, distant stars and galaxies. Answering two key questions would go a long way toward overcoming that hurdle: Would particle radiation pose too grave a threat to human life throughout a round trip to the red planet? And, could the very timing of a mission to Mars help shield astronauts and the spacecraft from the radiation? A team of space scientists answers those two questions with a "no" and a "yes." That is, humans should be able to safely travel to and from Mars, provided that the spacecraft has sufficient shielding and the round trip is shorter than approximately four years. And the timing of a human mission to Mars would indeed make a difference: The scientists determined that the best time for a flight to leave Earth would be when solar activity is at its peak, known as the solar maximum. The scientists' calculations demonstrate that it would be possible to shield a Mars-bound spacecraft from energetic particles from the Sun because, during solar maximum, the most dangerous and energetic particles from distant galaxies are deflected by the enhanced solar activity. A trip of that length would be conceivable. The average flight to Mars takes about nine months, so depending on the timing of launch and available fuel, it is plausible that a human mission could reach the planet and return to Earth in less than two years. The study shows that while space radiation imposes strict limitations on how heavy the spacecraft can be and the time of launch, and it presents technological difficulties for human missions to Mars, such a mission is viable.

The researchers recommend a mission not longer than four years because a longer journey would expose astronauts to a dangerously high amount of radiation during the round trip -- even assuming they went when it was relatively safer than at other times. They also report that the main danger to such a flight would be particles from outside of our solar system. Researchers combined geophysical models of particle radiation for a solar cycle with models for how radiation would affect both human passengers -- including its varying effects on different bodily organs -- and a spacecraft. The modelling determined that having a spacecraft's shell built out of a relatively thick material could help protect astronauts from radiation, but that if the shielding is too thick, it could actually increase the amount of secondary radiation to which they are exposed. The two main types of hazardous radiation in space are solar energetic particles and galactic cosmic rays; the intensity of each depends on solar activity. Galactic cosmic ray activity is lowest within the six to 12 months after the peak of solar activity, while solar energetic particles' intensity is greatest during solar maximum.

Harvard-Smithsonian Center for Astrophysics

In 2019, astronomers discovered a comet from another star system. Named Borisov, the icy snowball travelled 110,000 miles per hour and marked the first and only interstellar comet ever detected by humans. But what if these interstellar visitors -- comets, meteors, asteroids and other debris from beyond our solar system -- are more common than we think? In a new study, astronomers present new calculations showing that in the Oort Cloud -- a shell of debris in the farthest reaches of our solar system -- interstellar objects outnumber objects belonging to our solar system. The calculations, made using conclusions drawn from Borisov, include significant uncertainties, But even after taking these into consideration, interstellar visitors prevail over objects that are native to the solar system. But if there are so many interstellar visitors, why have we only ever seen one? We just don't have the technology to see them yet. Consider that the Oort Cloud spans a region some 200 billion to 10 trillion miles away from our Sun -- and unlike stars, objects in the Oort Cloud don't produce their own light. Those two factors make debris in the outer solar system incredibly hard to see. These results suggest that the abundances of interstellar and Oort cloud objects are comparable closer to the Sun than Saturn. This can be tested with current and future solar system surveys. When looking at the asteroid data in that region, the question is: are there asteroids that really are interstellar that we just didn't recognize before? Astronomers explain that there are some asteroids that get detected but aren't observed or followed up on year after year. We think they are asteroids, then we lose them without doing a detailed look.

Interstellar objects in the planetary region of the solar system would be rare, but the results clearly show they are more common than solar system material in the dark reaches of the Oort cloud. Observations with next-generation technology may help confirm the team's results. The launch of the Vera C. Rubin Observatory, slated for 2022, will "blow previous searches for interstellar objects out of the water and hopefully help detect many more visitors like Borisov. The Transneptunian Automated Occultation Survey (TAOS II), which is specifically designed to detect comets in the far reaches of our solar system, may also be able to detect one of these passersby. TAOS II may come online as early as this year. The abundance of interstellar objects in the Oort Cloud suggests that much more debris is left over from the formation of planetary systems than previously thought. The findings show that interstellar objects can place interesting constraints on planetary system formation processes, since their implied abundance requires a significant mass of material to be ejected in the form of planetesimals. Together with observational studies of protoplanetary disks and computational approaches to planet formation, the study of interstellar objects could help us unlock the secrets of how our planetary system -- and others -- formed.

Université de Genève

Brown dwarfs are astronomical objects with masses between those of planets and stars. The question of where exactly the limits of their mass lie remains a matter of debate, especially since their constitution is very similar to that of low-mass stars. So how do we know whether we are dealing with a brown dwarf or a very low mass star? An international team has identified five objects that have masses near the border separating stars and brown dwarfs that could help scientists understand the nature of these mysterious objects. Like Jupiter and other giant gas planets, stars are mainly made of hydrogen and helium. But unlike gas planets, stars are so massive and their gravitational force so powerful that hydrogen atoms fuse to produce helium, releasing huge amounts of energy and light. Brown dwarfs, on the other hand, are not massive enough to fuse hydrogen and therefore cannot produce the enormous amount of light and heat of stars. Instead, they fuse relatively small stores of a heavier atomic version of hydrogen: deuterium. This process is less efficient and the light from brown dwarfs is much weaker than that from stars. This is why scientists often refer to them as 'failed stars'. However, we still do not know exactly where the mass limits of brown dwarfs lie, limits that allow them to be distinguished from low-mass stars that can burn hydrogen for many billions of years, whereas a brown dwarf will have a short burning stage and then a colder life. These limits vary depending on the chemical composition of the brown dwarf, for example, or the way it formed, as well as its initial radius. So far, astronomers have only accurately characterised about 30 brown dwarfs. Compared to the hundreds of planets that astronomers know in detail, this is very few. All the more so if one considers that their larger size makes brown dwarfs easier to detect than planets.

The team characterized five companions that were originally identified with the Transiting Exoplanet Survey Satellite (TESS) as TESS objects of interest (TOI) -- TOI-148, TOI-587, TOI-681, TOI-746 and TOI-1213. These are called 'companions' because they orbit their respective host stars. They do so with periods of 5 to 27 days, have radii between 0.81 and 1.66 times that of Jupiter and are between 77 and 98 times more massive. This places them on the borderline between brown dwarfs and stars. These five new objects therefore contain valuable information. One of the clues the scientists found to show these objects are brown dwarfs is the relationship between their size and age. Brown dwarfs are supposed to shrink over time as they burn up their deuterium reserves and cool down. Here the team found that the two oldest objects, TOI 148 and 746, have a smaller radius, while the two younger companions have larger radii. Yet these objects are so close to the limit that they could just as easily be very low-mass stars, and astronomers are still unsure whether they are brown dwarfs. Even with these additional objects, they still lack the numbers to draw definitive conclusions about the differences between brown dwarfs and low-mass stars.

University of Cambridge

A new class of exoplanet very different to our own, but which could support life, has been identified by astronomers, which could greatly accelerate the search for life outside our Solar System. In the search for life elsewhere, astronomers have mostly looked for planets of a similar size, mass, temperature and atmospheric composition to Earth. However, astronomers from the University of Cambridge believe there are more promising possibilities out there. The researchers have identified a new class of habitable planets, dubbed 'Hycean' planets -- hot, ocean-covered planets with hydrogen-rich atmospheres -- which are more numerous and observable than Earth-like planets.  The researchers say the results could mean that finding biosignatures of life outside our Solar System within the next two or three years is a real possibility. Many of the prime Hycean candidates identified by the researchers are bigger and hotter than Earth, but still have the characteristics to host large oceans that could support microbial life similar to that found in some of Earth's most extreme aquatic environments. These planets also allow for a far wider habitable zone, or 'Goldilocks zone', compared to Earth-like planets. This means that they could still support life even though they lie outside the range where a planet similar to Earth would need to be in order to be habitable. Thousands of planets outside our Solar System have been discovered since the first exoplanet was identified nearly 30 years ago. The vast majority are planets between the sizes of Earth and Neptune and are often referred to as 'super-Earths' or 'mini-Neptunes': they can be predominantly rocky or ice giants with hydrogen-rich atmospheres, or something in between. Most mini-Neptunes are over 1.6 times the size of Earth: smaller than Neptune but too big to have rocky interiors like Earth. Earlier studies of such planets have found that the pressure and temperature beneath their hydrogen-rich atmospheres would be too high to support life. However, a recent study on the mini-Neptune K2-18b found that in certain conditions these planets could support life. The result led to a detailed investigation into the full range of planetary and stellar properties for which these conditions are possible, which known exoplanets may satisfy those conditions, and whether their biosignatures may be observable.

The investigation led the researchers to identify a new class of planets, Hycean planets, with massive planet-wide oceans beneath hydrogen-rich atmospheres. Hycean planets can be up to 2.6 times larger than Earth and have atmospheric temperatures up to nearly 200 degrees Celsius, but their oceanic conditions could be similar to those conducive for microbial life in Earth's oceans. Such planets also include tidally locked 'dark' Hycean worlds that may have habitable conditions only on their permanent night sides, and 'cold' Hycean worlds that receive little radiation from their stars. Planets of this size dominate the known exoplanet population, although they have not been studied in nearly as much detail as super-Earths. Hycean worlds are likely quite common, meaning that the most promising places to look for life elsewhere in the Galaxy may have been hiding in plain sight. However, size alone is not enough to confirm whether a planet is Hycean: other aspects such as mass, temperature and atmospheric properties are required for confirmation. When trying to determine what the conditions are like on a planet many light years away, astronomers first need to determine whether the planet lies in the habitable zone of its star, and then look for molecular signatures to infer the planet's atmospheric and internal structure, which govern the surface conditions, presence of oceans and potential for life. Astronomers also look for certain biosignatures which could indicate the possibility of life. Most often, these are oxygen, ozone, methane and nitrous oxide, which are all present on Earth. There are also a number of other biomarkers, such as methyl chloride and dimethyl sulphide, that are less abundant on Earth but can be promising indicators of life on planets with hydrogen-rich atmospheres where oxygen or ozone may not be as abundant. The team identified a sizeable sample of potential Hycean worlds which are prime candidates for detailed study with next-generation telescopes, such as the James Webb Space Telescope (JWST), which is due to be launched later this year. These planets all orbit red dwarf stars between 35-150 light years away: close by astronomical standards. Planned JWST observations of the most promising candidate, K2-18b, could lead to the detection of one or more biosignature molecules.

Nagoya University

Astronomers have succeeded for the first time in quantifying the proton and electron components of cosmic rays in a supernova remnant. At least 70% of the very-high-energy gamma rays emitted from cosmic rays are due to relativistic protons, according to the novel imaging analysis of radio, X-ray, and gamma-ray radiation. The acceleration site of protons, the main components of cosmic rays, has been a 100-year mystery in modern astrophysics, this is the first time that the amount of cosmic rays being produced in a supernova remnant has been quantitatively shown and is an epoch-making step in the elucidation of the origin of cosmic rays. The origin of cosmic rays, the particles with the highest energy in the Universe, has been a great mystery since their discovery in 1912. Because cosmic rays promote the chemical evolution of interstellar matter, understanding their origin is critical in understanding the evolution of our Galaxy. The cosmic rays are thought to be accelerated by supernova remnants (the after-effects of supernova explosions) in our Galaxy and travelled to the Earth at almost the speed of light. Recent progress in gamma-ray observations has revealed that many supernova remnants emit gamma-rays at teraelectronvolts (TeV) energies. If gamma rays are produced by protons, which are the main component of cosmic rays, then the supernova remnant origin of cosmic rays can be verified. However, gamma rays are also produced by electrons, it is necessary to determine whether the proton or electron origin is dominant, and to measure the ratio of the two contributions. The results of this study provide compelling evidence of gamma rays originating from the proton component, which is the main component of cosmic rays, and clarify that Galactic cosmic rays are produced by supernova remnants.

The originality of this research is that gamma-ray radiation is represented by a linear combination of proton and electron components. Astronomers knew a relation that the intensity of gamma-ray from protons is proportional to the interstellar gas density obtained by radio-line imaging observations. On the other hand, gamma-rays from electrons are also expected to be proportional to X-ray intensity from electrons. Therefore, they expressed the total gamma-ray intensity as the sum of two gamma-ray components, one from the proton origin and the other from the electron origin. This led to a unified understanding of three independent observables. This method was first proposed in this study. As a result, it was shown that gamma rays from protons and electrons account for 70% and 30% of the total gamma-rays, respectively. This is the first time that the two origins have been quantified. The results also demonstrate that gamma rays from protons are dominated in interstellar gas-rich regions, whereas gamma rays from electrons are enhanced in the gas-poor region. This confirms that the two mechanisms work together and supporting the predictions of previous theoretical studies.

Lund University

Using a supercomputer simulation, a research team in Sweden has succeeded in following the development of a galaxy over a span of 13.8 billion years. The study shows how, due to interstellar frontal collisions, young and chaotic galaxies over time mature into spiral galaxies such as the Milky Way. Soon after the Big Bang 13.8 billion years ago, the Universe was an unruly place. Galaxies constantly collided. Stars formed at an enormous rate inside gigantic gas clouds. However, after a few billion years of intergalactic chaos, the unruly, embryonic galaxies became more stable and over time matured into well-ordered spiral galaxies. The exact course of these developments has long been a mystery to the world's astronomers. However, in a new study, researchers have been able to provide some clarity on the matter. Astronomers use the Milky Way's stars as a starting point. The stars act as time capsules that divulge secrets about distant epochs and the environment in which they were formed. Their positions, speeds and amounts of various chemical elements can therefore, with the assistance of computer simulations, help us understand how our own galaxy was formed. They have discovered that when two large galaxies collide, a new disc can be created around the old one due to the enormous inflows of star-forming gas. Our simulation shows that the old and new discs slowly merged over a period of several billion years. This is something that not only resulted in a stable spiral galaxy, but also in populations of stars that are similar to those in the Milky Way. The new findings will help astronomers to interpret current and future mappings of the Milky Way. The study points to a new direction for research in which the main focus will be on the interaction between large galaxy collisions and how spiral galaxies' discs are formed. The research team in Lund has already started new super computer simulations in cooperation with the research infrastructure PRACE (Partnership for Advanced Computing in Europe).

University of Chicago

Scientists have proposed a new theory that neutrons might communicate under certain circumstances, forming a new sort of 'unparticle'--which could offer evidence of a new kind of symmetry in physics. Even though neutrons love to partner with protons to make the nucleus of an atom, the particles have always been notorious for their reluctance to bind with each other. But according to a new proposed theory, these particles might communicate under certain circumstances, forming a new sort of 'unparticle'--which could offer evidence of a new kind of symmetry in physics.  Dam Thanh Son, the University Professor of Physics at the University of Chicago, laid out the argument in a study published in Proceedings of the National Academy of Sciences, which he co-authored with Hans-Werner Hammer of the Technical University of Darmstadt in Germany. The new study was inspired by an idea first proposed in 2007 by Harvard University professor Howard Georgi, who suggested that there could be a phenomenon beyond our traditional idea of matter. Son and Hammer wanted to try applying this concept to understand the behaviour of particles in the nuclei of atoms--especially more exotic nuclei, which wink in and out existence during violent events in the Universe, such as when stars explode. To study these exotic atomic nuclei on Earth, scientists smash heavy nuclei into each other in accelerators. What comes out is a new nucleus, and a shower of neutrons. Son and Hammer observed that as the neutrons stream out and away, a few that are going in the same direction may continue to "talk" to one another--even after the others have stopped interacting. This sustained communication between neutrons could constitute a fuzzy "unnucleus," with its own properties distinct from normal nuclei.

It's a bit like the difference between being hit by a stone, and being hit by a stream of water. Both carry energy, but the form is different. In their new study, Son and Hammer laid out how and where to look for evidence of these "unnuclei" in accelerators, and a general explanation for the field of what they playfully called "unnuclear physics." This could be a manifestation, the scientists said, of a type of symmetry called conformal symmetry. Symmetries are fundamental to modern physics; they are common features that remain even as a system changes--the most famous being that the speed of light is constant throughout the Universe. In conformal symmetry, a space distorted, but all angles are kept unchanged. For example, when one draws a 2D map of the entire 3D Earth, it is impossible to preserve all distances and angles at the same time. However, some maps, such as a common version first drawn by Gerardus Mercator, are drawn so that all angles remain correct, but at the cost of greatly distorting the distances near the poles. Because the calculations are so robust even if some details are missing, Son said that if the argument is confirmed, physicists might be able to use these formulas to check other calculations. He and Hammer also noted that this behaviour may occur when atoms are cooled to super-low temperatures, and in exotic particles called tetraquarks, made up of two quarks and two antiquarks.

Bulletin compiled by Clive Down

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Astronomy Group / The Night Sky in Semtember 2021
September 03, 2021, 12:16:26 pm
The Night Sky in September 2021

September offers stargazers a last chance to see the long, starry arc of the Milky Way and all its attendant splendour. The rich constellations of Scorpius and Sagittarius are moving westward, but the lengthening nights keep these stars accessible for a little longer, at least for observers in the northern hemisphere. In the east, the relatively star-poor constellations of Pegasus, Capricornus, and Piscis Austrinus are moving into view along with hundreds of galaxies accessible with a small telescope. Also, this month, Jupiter and Saturn liven up the southwestern sky, the planet Neptune reaches opposition, and Venus remains low but bright in the west after sunset. Here's what to see in the night sky this month...



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