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Topics - Geoffw

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Astronomy Group / The Night Sky in August 2021
August 04, 2021, 12:42:55 pm
The Night Sky in August 2021



t's an extra good month for stargazing! Both Jupiter and Saturn reach opposition in August and make their best
apparitions of the year. The grand Perseid meteor shower peaks under nearly moonless conditions, ideal for some
summer stargazing under the Milky Way. Venus hangs low and bright over the north-western horizon after sunset,
and tiny Mercury makes a very close approach to Mars on the 18th in the same part of the sky. Early risers get to see
a slender crescent Moon tangled in the stars of the Pleiades and Hyades star clusters in the pre-dawn sky. Here's
what to see in the night sky this month.

CLICK HERE  The Night Sky in August 2021.pdf
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Local Artists Exhibition
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Astronomy Group / Beautiful Video of Jupiter
July 30, 2021, 11:03:24 am
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General Chatty Stuff / Beijing Hotel Brochure
July 26, 2021, 01:11:11 pm
I know this has been around for a while but it still makes me chuckle!

image_2021-07-26_121028.png
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Virgin Galactic launch 2.00pm BST 11th July

"We are at the vanguard of a new industry determined to pioneer twenty-first century spacecraft, which will open space to everybody -- and change the world for good."

- Sir Richard Branson, Founder, Virgin Galactic


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THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 545 2021 July 11

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.

DISCOVERY OF GIANT COMET
Spaceweather.com

Astronomers have discovered a comet so big, it might actually be a minor planet. The object is named 2014 UN271. Astronomers Pedro Bernardinelli and Gary Bernstein found it in archival images from the Dark Energy Survey. It appears to be about 100 km wide, 2 or 3 times bigger than record-breaking Comet Hale-Bopp of the 1990s. Although 2014 UN271 is falling toward the Sun, we may never see it with our naked eyes. At closest approach in early 2031, the behemoth comet will be just outside the orbit of Saturn, too far for naked-eye viewing. Some astronomers are estimating a maximum brightness near magnitude +17, about the same as Pluto's moon Charon. 2014 UN271 has an extremely elongated orbit stretching from ~the neighbourhood of Saturn out to a distance of almost a light year. At the far reaches of its orbit, 2014 UN271 barely feels the Sun's gravity and could be snatched out of the Solar System altogether by the ephemeral pull of galactic tides. Discovering such a traveller during its brief time among the planets is very lucky indeed. There is talk of a space mission to intercept 2014 UN271. The European Space Agency is building a probe called Comet Interceptor designed to investigate comets coming from deep space. It, or something like it, might be able to visit 2014 UN271 a decade from now. With an object like this, we have to expect surprises. 2014 UN271 certainly poses no threat to Earth, but it could brighten more (or less) than expected. Multiple groups of astronomers have already detected signs of out-gassing even though 2014 UN271 is still beyond Uranus. Early signs of activity may bode well for future visibility through small telescopes if not the unaided eye.

METHANE PLUMES ON SATURN'S MOON ENCELADUS
University of Arizona

Giant water plumes erupting from Enceladus have long fascinated scientists and the public alike, inspiring research and speculation about the vast ocean that is believed to be sandwiched between the moon's rocky core and its icy shell. Flying through the plumes and sampling their chemical makeup, the Cassini spacecraft detected a relatively high concentration of certain molecules associated with hydrothermal vents on the bottom of Earth's oceans, specifically dihydrogen, methane and carbon dioxide. The amount of methane found in the plumes was particularly unexpected. Researchers applied new mathematical models that combine geochemistry and microbial ecology to analyze Cassini plume data and model the possible processes that would best explain the observations. They conclude that Cassini's data are consistent either with microbial hydrothermal vent activity, or with processes that don't involve life forms but are different from the ones known to occur on Earth. On Earth, hydrothermal activity occurs when cold seawater seeps into the ocean floor, circulates through the underlying rock and passes close by a heat source, such as a magma chamber, before spewing out into the water again through hydrothermal vents. On Earth, methane can be produced through hydrothermal activity, but at a slow rate. Most of the production is due to microorganisms that harness the chemical disequilibrium of hydrothermally produced dihydrogen as a source of energy, and produce methane from carbon dioxide in a process called methanogenesis. The team looked at Enceladus' plume composition as the end result of several chemical and physical processes taking place in the moon's interior. First, the researchers assessed what hydrothermal production of dihydrogen would best fit Cassini's observations, and whether this production could provide enough "food" to sustain a population of Earthlike hydrogenotrophic methanogens. To do that, they developed a model for the population dynamics of a hypothetical hydrogenotrophic methanogen, whose thermal and energetic niche was modelled after known strains from Earth.

The authors then ran the model to see whether a given set of chemical conditions, such as the dihydrogen concentration in the hydrothermal fluid, and temperature would provide a suitable environment for these microbes to grow. They also looked at what effect a hypothetical microbe population would have on its environment -- for example, on the escape rates of dihydrogen and methane in the plume. The results suggest that even the highest possible estimate of abiotic methane production -- or methane production without biological aid -- based on known hydrothermal chemistry is far from sufficient to explain the methane concentration measured in the plumes. Adding biological methanogenesis to the mix, however, could produce enough methane to match Cassini's observations. For example, methane could come from the chemical breakdown of primordial organic matter that may be present in Enceladus' core and that could be partially turned into dihydrogen, methane and carbon dioxide through the hydrothermal process. This hypothesis is very plausible if it turns out that Enceladus formed through the accretion of organic-rich material supplied by comets.

EARTH-LIKE BIOSPHERES MAY BE RARE
RAS

A new analysis of known exoplanets has revealed that Earth-like conditions on potentially habitable planets may be much rarer than previously thought. The work focuses on the conditions required for oxygen-based photosynthesis to develop on a planet, which would enable complex biospheres of the type found on Earth. The number of confirmed planets in our own Milky Way galaxy now numbers into the thousands. However planets that are both Earth-like and in the habitable zone - the region around a star where the temperature is just right for liquid water to exist on the surface - are much less common. At the moment, only a handful of such rocky and potentially habitable exoplanets are known. However the new research indicates that none of these has the theoretical conditions to sustain an Earth-like biosphere by means of 'oxygenic' photosynthesis - the mechanism plants on Earth use to convert light and carbon dioxide into oxygen and nutrients. Only one of those planets comes close to receiving the stellar radiation necessary to sustain a large biosphere: Kepler−442b, a rocky planet about twice the mass of the Earth, orbiting a moderately hot star around 1,200 light years away. The study looked in detail at how much energy is received by a planet from its host star, and whether living organisms would be able to efficiently produce nutrients and molecular oxygen, both essential elements for complex life as we know it, via normal oxygenic photosynthesis. By calculating the amount of photosynthetically active radiation (PAR) that a planet receives from its star, the team discovered that stars around half the temperature of our Sun cannot sustain Earth-like biospheres because they do not provide enough energy in the correct wavelength range. Oxygenic photosynthesis would still be possible, but such planets could not sustain a rich biosphere.

Planets around even cooler stars known as red dwarfs, which smoulder at roughly a third of our Sun's temperature, could not receive enough energy to even activate photosynthesis. Stars that are hotter than our Sun are much brighter, and emit up to ten times more radiation in the necessary range for effective photosynthesis than red dwarfs, however generally do not live long enough for complex life to evolve. Since red dwarfs are by far the most common type of star in our galaxy, this result indicates that Earth-like conditions on other planets may be much less common than we might hope. The study puts strong constraints on the parameter space for complex life, so unfortunately it appears that the "sweet spot" for hosting a rich Earth-like biosphere is not so wide.

EVIDENCE FOR POPULATION OF FREE-FLOATING PLANETS
RAS

Tantalising evidence has been uncovered for a mysterious population of "free-floating" planets, planets that may be alone in deep space, unbound to any host star. The results include four new discoveries that are consistent with planets of similar masses to Earth. The study used data obtained in 2016 during the K2 mission phase of NASA's Kepler Space Telescope. During this two-month campaign, Kepler monitored a crowded field of millions of stars near the centre of our Galaxy every 30 minutes in order to find rare gravitational microlensing events. The study team found 27 short-duration candidate microlensing signals that varied over timescales of between an hour and 10 days. Many of these had been previously seen in data obtained simultaneously from the ground. However, the four shortest events are new discoveries that are consistent with planets of similar masses to Earth. These new events do not show an accompanying longer signal that might be expected from a host star, suggesting that these new events may be free-floating planets. Such planets may perhaps have originally formed around a host star before being ejected by the gravitational tug of other, heavier planets in the system. Predicted by Albert Einstein 85 years ago as a consequence of his General Theory of Relativity, microlensing describes how the light from a background star can be temporarily magnified by the presence of other stars in the foreground. This produces a short burst in brightness that can last from hours to a few days. Roughly one out of every million stars in our Galaxy is visibly affected by microlensing at any given time, but only a few percent of these are expected to be caused by planets.

Kepler was not designed to find planets using microlensing, nor to study the extremely dense star fields of the inner Galaxy. This meant that new data reduction techniques had to be developed to look for signals within the Kepler dataset. These signals are extremely difficult to find. Astronomers pointed an elderly, ailing telescope with blurred vision at one the most densely crowded parts of the sky, where there are already thousands of bright stars that vary in brightness, and thousands of asteroids that skim across the field. From that cacophony, astronomers try to extract tiny, characteristic brightenings caused by planets, and they only have one chance to see a signal before it's gone. It's about as easy as looking for the single blink of a firefly in the middle of a motorway, using only a handheld phone. Kepler has achieved what it was never designed to do, in providing further tentative evidence for the existence of a population of Earth-mass, free-floating planets. Now it passes the baton on to other missions that will be designed to find such signals, signals so elusive that Einstein himself thought that they were unlikely ever to be observed. Confirming the existence and nature of free-floating planets will be a major focus for upcoming missions such as the NASA Nancy Grace Roman Space Telescope, and possibly the ESA Euclid mission, both of which will be optimised to look for microlensing signals.

EXOPLANETS IN 2,034 STAR SYSTEMS COULD SEE EARTH
Cornell University

Scientists have identified 2,034 nearby star-systems -- within the cosmic distance of 326 light-years -- that could find Earth merely by watching our pale blue dot cross our Sun. That's 1,715 star-systems that could have spotted Earth since human civilization blossomed about 5,000 years ago, and 319 more star-systems that will be added over the next 5,000 years. Exoplanets around these nearby stars have a cosmic front-row seat to see if Earth holds life. Of the 2,034 star-systems passing through the Earth Transit Zone over the 10,000-year period examined, 117 objects lie within about 100 light-years of the Sun and 75 of these objects have been in the Earth Transit Zone since commercial radio stations on Earth began broadcasting into space about a century ago. Included in the catalogue of 2,034 star-systems are seven known to host exoplanets. Each one of these worlds has had or will have an opportunity to detect Earth, just as Earth's scientists have found thousands of worlds orbiting other stars through the transit technique. By watching distant exoplanets transit -- or cross -- their own Sun, Earth's astronomers can interpret the atmospheres backlit by that Sun. If exoplanets hold intelligent life, they can observe Earth backlit by the Sun and see our atmosphere's chemical signatures of life.

The Ross 128 system, with a red dwarf host star located in the Virgo constellation, is about 11 light-years away and is the second-closest system with an Earth-size exoplanet (about 1.8 times the size of our planet). Any inhabitants of this exoworld could have seen Earth transit our own Sun for 2,158 years, starting about 3,057 years ago; they lost their vantage point about 900 years ago. The Trappist-1 system, at 45 light-years from Earth, hosts seven transiting Earth-size planets -- four of them in the temperate, habitable zone of that star. While we have discovered the exoplanets around Trappist-1, they won't be able to spot us until their motion takes them into the Earth Transit Zone in 1,642 years. Potential Trappist-1 system observers will remain in the cosmic Earth transit stadium seats for 2,371 years. Analysis shows that even the closest stars generally spend more than 1,000 years at a vantage point where they can see Earth transit. If we assume the reverse to be true, that provides a healthy timeline for nominal civilizations to identify Earth as an interesting planet. The Breakthrough Starshot initiative is an ambitious project underway that is looking to launch a nano-sized spacecraft toward the closest exoplanet detected around Proxima Centauri -- 4.2 light-years from us -- and fully characterize that world. One might imagine that worlds beyond Earth that have already detected us, are making the same plans for our planet and solar system. This catalogue is an intriguing thought experiment for which one of our neighbours might be able to find us.

WHITE DWARF IS SO MASSIVE IT MIGHT COLLAPSE
W. M. Keck Observatory

Astronomers have discovered the smallest and most massive white dwarf ever seen. The smouldering cinder, which formed when two less massive white dwarfs merged, is heavy, packing a mass greater than that of our Sun into a body about the size of our Moon. It may seem counterintuitive, but smaller white dwarfs happen to be more massive. This is due to the fact that white dwarfs lack the nuclear burning that keep up normal stars against their own self gravity, and their size is instead regulated by quantum mechanics. The discovery was made by the Zwicky Transient Facility, or ZTF, which operates at Caltech's Palomar Observatory; two Hawai'i telescopes -- W. M. Keck Observatory on Maunakea, Hawai'i Island and University of Hawai'i Institute for Astronomy's Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) on Haleakala, Maui -- helped characterize the dead star, along with the 200-inch Hale Telescope at Palomar, the European Gaia space observatory, and NASA's Neil Gehrels Swift Observatory. White dwarfs are the collapsed remnants of stars that were once about eight times the mass of our Sun or lighter. Our Sun, for example, after it first puffs up into a red giant in about 5 billion years, will ultimately slough off its outer layers and shrink down into a compact white dwarf. About 97 percent of all stars become white dwarfs. While our Sun is alone in space without a stellar partner, many stars orbit around each other in pairs. The stars grow old together, and if they are both less than eight solar-masses, they will both evolve into white dwarfs. The new discovery provides an example of what can happen after this phase. The pair of white dwarfs, which spiral around each other, lose energy in the form of gravitational waves and ultimately merge. If the dead stars are massive enough, they explode in what is called a type Ia supernova. But if they are below a certain mass threshold, they combine together into a new white dwarf that is heavier than either progenitor star. This process of merging boosts the magnetic field of that star and speeds up its rotation compared to that of the progenitors.

Astronomers say that the newfound tiny white dwarf, named ZTF J1901+1458, took the latter route of evolution; its progenitors merged and produced a white dwarf 1.35 times the mass of our Sun. The white dwarf has an extreme magnetic field almost 1 billion times stronger than our Sun's and whips around on its axis at a frenzied pace of one revolution every seven minutes (the zippiest white dwarf known, called EPIC 228939929, rotates every 5.3 minutes. What's more, astronomers think that the merged white dwarf may be massive enough to evolve into a neutron-rich dead star, or neutron star, which typically forms when a star much more massive than our Sun explodes in a supernova. If this neutron star formation hypothesis is correct, it may mean that a significant portion of other neutron stars take shape in this way. The newfound object's close proximity (about 130 light-years away) and its young age (about 100 million years old or less) indicate that similar objects may occur more commonly in our galaxy. Data from Swift, which observes ultraviolet light, helped nail down the size and mass of the white dwarf. With a diameter of 2,670 miles, ZTF J1901+1458 secures the title for the smallest known white dwarf, edging out previous record holders, RE J0317-853 and WD 1832+089, which each have diameters of about 3,100 miles.

SPLIT IN LOCAL COSMOS
Washington University in St. Louis

In 2011, scientists confirmed a suspicion: There was a split in the local cosmos. Samples of the solar wind brought back to Earth by the Genesis mission definitively determined oxygen isotopes in the sun differ from those found on Earth, the moon and the other planets and satellites in the solar system. Early in the solar system's history, material that would later coalesce into planets had been hit with a hefty dose of ultraviolet light, which can explain this difference. Where did it come from? Two theories emerged: Either the ultraviolet light came from our then-young Sun, or it came from a large nearby star in the Sun's stellar nursery. Now, researchers have determined which was responsible for the split. It was most likely light from a long-dead massive star that left this impression on the rocky bodies of the solar system. All of that profundity was packed into a mere 85 grams of rock, a piece of an asteroid found as a meteorite in Algeria in 1990, named Acfer 094. Asteroids and planets formed from the same presolar material, but they've been influenced by different natural processes. The rocky building blocks that coalesced to form asteroids and planets were broken up and battered; vaporized and recombined; and compressed and heated. But the asteroid that Acfer 094 came from managed to survive for 4.6 billion years mostly unscathed. Acfer 094 is also the only meteorite that contains cosmic symplectite, an intergrowth of iron-oxide and iron-sulphide with extremely heavy oxygen isotopes -- a significant finding. The Sun contains about 6% more of the lightest oxygen isotope compared with the rest of the solar system. That can be explained by ultraviolet light shining on the solar system's building blocks, selectively breaking apart carbon monoxide gas into its constituent atoms. That process also creates a reservoir of much heavier oxygen isotopes. Until cosmic symplectite, however, no one had found this heavy isotope signature in samples of solar system materials. With only three isotopes, however, simply finding the heavy oxygen isotopes wasn't enough to answer the question of the origin of the light. Different ultraviolet spectra could have created the same result.

That's when the team came up with the idea of sulphur isotopes. Sulphur's four isotopes would leave their marks in different ratios depending on the spectrum of ultraviolet light that irradiated hydrogen sulphide gas in the proto-solar system. A massive star and a young sun-like star have different ultraviolet spectra. Cosmic symplectite formed when ices on the asteroid melted and reacted with small pieces of iron-nickel metal. In addition to oxygen, cosmic symplectite contains sulphur in iron sulphide. If its oxygen witnessed this ancient astrophysical process -- which led to the heavy oxygen isotopes -- perhaps its sulphur did, too. Sulphur and oxygen isotope measurements of cosmic symplectite in Acfer 094 proved another challenge. The grains, tens of micrometers in size and a mixture of minerals, required new techniques on two different in-situ secondary-ion mass spectrometers. The sulphur isotope measurements of cosmic symplectite were consistent with ultraviolet irradiation from a massive star, but did not fit the UV spectrum from the young Sun. The results give a unique perspective on the astrophysical environment of the Sun's birth 4.6 billion years ago. Neighbouring massive stars were likely close enough that their light affected the solar system's formation. Such a nearby massive star in the night sky would appear brighter than the full Moon. Today, we can look to the skies and see a similar origin story play out elsewhere in the galaxy. We see nascent planetary systems, called proplyds, in the Orion nebula that are being photoevaporated by ultraviolet light from nearby massive O and B stars. If the proplyds are too close to these stars, they can be torn apart, and planets never form. We now know our own solar system at its birth was close enough to be affected by the light of these stars. But thankfully, not too close.

THE GOLDILOCKS SUPERNOVA
University of California - Santa Barbara

Scientists have discovered the first convincing evidence for a new type of stellar explosion -- an electron-capture supernova. While they have been theorized for 40 years, real-world examples have been elusive. They are thought to arise from the explosions of massive super-asymptotic giant branch (SAGB) stars, for which there has also been scant evidence. The discovery also sheds new light on the thousand-year mystery of the supernova from A.D. 1054 that was visible all over the world in the daytime, before eventually becoming the Crab Nebula. Historically, supernovae have fallen into two main types: thermonuclear and iron-core collapse. A thermonuclear supernova is the explosion of a white dwarf star after it gains matter in a binary star system. These white dwarfs are the dense cores of ash that remain after a low-mass star (one up to about 8 times the mass of the Sun) reaches the end of its life. An iron core-collapse supernova occurs when a massive star -- one more than about 10 times the mass of the Sun -- runs out of nuclear fuel and its iron core collapses, creating a black hole or neutron star. Between these two main types of supernovae are electron-capture supernovae. These stars stop fusion when their cores are made of oxygen, neon and magnesium; they aren't massive enough to create iron. While gravity is always trying to crush a star, what keeps most stars from collapsing is either ongoing fusion or, in cores where fusion has stopped, the fact that you can't pack the atoms any tighter. In an electron capture supernova, some of the electrons in the oxygen-neon-magnesium core get smashed into their atomic nuclei in a process called electron capture. This removal of electrons causes the core of the star to buckle under its own weight and collapse, resulting in an electron-capture supernova. If the star had been slightly heavier, the core elements could have fused to create heavier elements, prolonging its life. So it is a kind of reverse Goldilocks situation: The star isn't light enough to escape its core collapsing, nor is it heavy enough to prolong its life and die later via different means. Over the decades, theorists have formulated predictions of what to look for in an electron-capture supernova and their SAGB star progenitors. The stars should have a lot of mass, lose much of it before exploding, and this mass near the dying star should be of an unusual chemical composition. Then the electron-capture supernova should be weak, have little radioactive fallout, and have neutron-rich elements in the core.

The new study involved a team of scientists using dozens of telescopes around and above the globe. The team found that the supernova SN 2018zd had many unusual characteristics, some of which were seen for the first time in a supernova. It helped that the supernova was relatively nearby -- only 31 million light-years away -- in the galaxy NGC 2146. This allowed the team to examine archival images taken by the Hubble Space Telescope prior to the explosion and to detect the likely progenitor star before it exploded. The observations were consistent with another recently identified SAGB star in the Milky Way, but inconsistent with models of red supergiants, the progenitors of normal iron core-collapse supernovae. The authors looked through all published data on supernovae, and found that while some had a few of the indicators predicted for electron-capture supernovae, only SN 2018zd had all six: an apparent SAGB progenitor, strong pre-supernova mass loss, an unusual stellar chemical composition, a weak explosion, little radioactivity and a neutron-rich core. The new discoveries also illuminate some mysteries of the most famous supernova of the past. In A.D. 1054 a supernova happened in the Milky Way Galaxy that, according to Chinese and Japanese records, was so bright that it could be seen in the daytime for 23 days, and at night for nearly two years. The resulting remnant, the Crab Nebula, has been studied in great detail. The Crab Nebula was previously the best candidate for an electron-capture supernova, but its status was uncertain partly because the explosion happened nearly a thousand years ago. The new result increases the confidence that the historic SN 1054 was an electron-capture supernova. It also explains why that supernova was relatively bright compared to the models: Its luminosity was probably artificially enhanced by the supernova ejecta colliding with material cast off by the progenitor star as was seen in SN 2018zd.

FIRST DETECTION OF BLACK HOLE-NEUTRON STAR MERGERS
Northwestern University

A long time ago, in two galaxies about 900 million light-years away, two black holes each gobbled up their neutron star companions, triggering gravitational waves that finally hit Earth in January 2020. Discovered by an international team of astrophysicists, two events -- detected just 10 days apart -- mark the first-ever detection of a black hole merging with a neutron star. The findings will enable researchers to draw the first conclusions about the origins of these rare binary systems and how often they merge. Gravitational waves have allowed us to detect collisions of pairs of black holes and pairs of neutron stars, but the mixed collision of a black hole with a neutron star has been the elusive missing piece of the family picture of compact object mergers. Completing this picture is crucial to constraining the host of astrophysical models of compact object formation and binary evolution. Inherent to these models are their predictions of the rates that black holes and neutron stars merge amongst themselves. With these detections, we finally have measurements of the merger rates across all three categories of compact binary mergers. The team observed the two new gravitational-wave events -- dubbed GW200105 and GW200115 -- on Jan. 5, 2020, and Jan. 15, 2020, during the second half of the LIGO and Virgo detectors third observing run, called O3b. Although multiple observatories carried out several follow-up observations, none observed light from either event, consistent with the measured masses and distances. All three large detectors (both LIGO instruments and the Virgo instrument) detected GW200115, which resulted from the merger of a 6-solar mass black hole with a 1.5-solar mass neutron star, roughly 1 billion light-years from Earth. With observations of the three widely separated detectors on Earth, the direction to the waves' origin can be determined to a part of the sky equivalent to the area covered by 2,900 full Moons. Just 10 days earlier, LIGO detected a strong signal from GW200105, using just one detector while the other was temporarily offline.

Virgo also was observing, the signal was too quiet in its data for Virgo to help detect it. From the gravitational waves, the astronomers inferred that the signal was caused by a 9-solar mass black hole colliding with a 1.9-solar mass compact object, which they ultimately concluded was a neutron star. This merger happened at a distance of about 900 million light-years from Earth. Because the signal was strong in only one detector, the astronomers could not precisely determine the direction of the waves' origin. Although the signal was too quiet for Virgo to confirm its detection, its data did help narrow down the source's potential location to about 17% of the entire sky, which is equivalent to the area covered by 34,000 full moons. Because the two events are the first confident observations of gravitational waves from black holes merging with neutron stars, the researchers now can estimate how often such events happen in the universe. Although not all events are detectable, the researchers expect roughly one such merger per month happens within a distance of one billion light-years. While it is unclear where these binary systems form, astronomers identified three likely cosmic origins: stellar binary systems, dense stellar environments including young star clusters, and the centers of galaxies. The team is currently preparing the detectors for a fourth observation run, to begin in summer 2022.

UNDERSTANDING THE ORIGINS OF MATTER IN THE MILKY WAY
University of Maryland Baltimore County

New findings suggest that carbon, oxygen, and hydrogen cosmic rays travel through the galaxy toward Earth in a similar way, but, surprisingly, that iron arrives at Earth differently. Learning more about how cosmic rays move through the galaxy helps address a fundamental, lingering question in astrophysics: How is matter generated and distributed across the Universe? Cosmic rays are atomic nuclei -- atoms stripped of their electrons -- that are constantly whizzing through space at nearly the speed of light. They enter Earth's atmosphere at extremely high energies. Information about these cosmic rays can give scientists clues about where they came from in the galaxy and what kind of event generated them. An instrument on the International Space Station (ISS) called the Calorimetric Electron Telescope (CALET) has been collecting data about cosmic rays since 2015. The data include details such as how many and what kinds of atoms are arriving, and how much energy they're arriving with. Cosmic rays arrive at Earth from elsewhere in the galaxy at a huge range of energies -- anywhere from 1 billion volts to 100 billion billion volts. The CALET instrument is one of extremely few in space that is able to deliver fine detail about the cosmic rays it detects. A graph called a cosmic ray spectrum shows how many cosmic rays are arriving at the detector at each energy level. The spectra for carbon, oxygen, and hydrogen cosmic rays are very similar, but the key finding from the new paper is that the spectrum for iron is significantly different. There are several possibilities to explain the differences between iron and the three lighter elements. The cosmic rays could accelerate and travel through the galaxy differently, although scientists generally believe they understand the latter.

An instrument like CALET is important for answering questions about how cosmic rays accelerate and travel, and where they come from. Instruments on the ground or balloons flown high in Earth's atmosphere were the main source of cosmic ray data in the past. But by the time cosmic rays reach those instruments, they have already interacted with Earth's atmosphere and broken down into secondary particles. With Earth-based instruments, it is nearly impossible to identify precisely how many primary cosmic rays and which elements are arriving, plus their energies. But CALET, being on the ISS above the atmosphere, can measure the particles directly and distinguish individual elements precisely. Iron is a particularly useful element to analyse. On their way to Earth, cosmic rays can break down into secondary particles, and it can be hard to distinguish between original particles ejected from a source (like a supernova) and secondary particles. That complicates deductions about where the particles originally came from. Measuring cosmic rays gives scientists a unique view into high-energy processes happening far, far away. The cosmic rays arriving at CALET represent "the stuff we're made of. We are made of stardust. The latest finding creates more questions than it answers, emphasizing that there is still more to learn about how matter is generated and moves around the galaxy.

OBSERVATIONS OF DISTANT GALAXIES CLOSE IN ON COSMIC DAWN
RAS

New observations of six of the most distant galaxies currently known have helped to pinpoint the moment of first light in the Universe, known as 'cosmic dawn'. Today our Universe is full of light, however this was not the case until the first stars and galaxies formed. The new work narrows down the moment when the Universe was first bathed in starlight to a small window just a few hundred million years after the Big Bang. Prior to this the Universe was a dark place, with dust and gas gradually collecting via gravity to eventually form these first stars and galaxies, bringing to an end the cosmic Dark Ages. The UK-led research team examined the ages of stars contained in six galaxies seen when the Universe was 550 million years old. Detailed observations of the average ages of the stars in each galaxy were made with the world's most powerful ground- and space-based telescopes. These new observations have pushed the earliest period of star formation back to well beyond the horizon accessible with current telescopes. However the team also predicts that the next generation of telescopes, such as the James Webb Space Telescope (JWST), due for launch later this year, will have the sensitivity to directly probe these earliest epochs of the Universe.

RUSSIA LAUNCHING NEW ISS MODULE
ARS Technica

The Russian space corporation, Roscosmos has released photos showing the much-anticipated Nauka space station module enclosed in its payload fairing. This will be Russia's first significant addition to the International Space Station in more than a decade, and it will provide the Russians with their first module dedicated primarily to research. "Nauka" means science in Russian. This is a sizable module, including crew quarters, an airlock for scientific experiments, and much more. With a mass of about 24 metric tons, it is about 20 percent larger than the biggest Russian segment of the station, the Zvezda service module. The timing for this launch, scheduled for as early as July 15 on a Proton rocket, is notable. For one, the multi-purpose Nauka module is more than a dozen years late due to a lack of budget for the project on top of technical issues. At times, it seemed like the module was never actually going to launch. Additionally, Russia is launching its largest module at a time when its future participation in the International Space Station program is uncertain. Russian officials have said the existing hardware on orbit, much of which is more than two decades old, is aging beyond repair. The Russians have said they may pull out of the program in 2025 and build a brand-new station.

So why launch a new module just a few years before exiting the station? One possibility is that the Russians are simply posturing. Some NASA officials have speculated privately that this may be an angle to obtain new funds from the United States. With the success of SpaceX's Crew Dragon vehicle and nearing availability of Boeing's Starliner, NASA is no longer annually sending hundreds of millions of dollars to Roscosmos to purchase Soyuz seats for access to the station. This was an important source of funding for Russia's space program. However, NASA would like to keep the station flying for another decade, and for this it needs the Russians. The first elements of the International Space Station were launched in 1998, and it was designed such that the US and Russian segments were dependent upon one another for attitude control, power, and other critical resources. The NASA officials suspect Russia may seek "maintenance" funding from the United States in return for keeping its part of the space station going. Nauka's launch is an important symbolic win for Russia's space program, in that it is increasingly rare for Roscosmos to develop and fly new hardware. Mostly, the program maintains and launches decades-old spacecraft such as the Soyuz vehicle and the Proton rocket. After being encapsulated in its payload fairing, Nauka will now move to a "filling station" at the Baikonur Cosmodrome in Kazakhstan, where it will be fuelled and pressurized. After that, it will be mated to its Proton rocket for a launch.  

Bulletin compiled by Clive Down

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
7


By Sid PerkinsJun. 4, 2021 , 5:15 PM

When continental plates smashed together about 12 million years ago, they didn't just raise new mountains in central Europe--they created the largest lake the world has ever known. This vast body of water--the Paratethys Sea--came to host species found nowhere else, including the world's smallest whales. Two new studies reveal how the ancient body of water took shape and how surrounding changes helped give rise to elephants, giraffes, and other large mammals that wander the planet today.

TO READ THE FULL ARTICLE CLICK HERE
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..........to our garden this afternoon, and the sad demise of a young blackbird we were getting to know!

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THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 544 2021 June 27

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.

ASTEROID 16 PSYCHE MIGHT NOT BE WHAT WE EXPECTED
University of Arizona

The widely studied metallic asteroid known as 16 Psyche was long thought to be the exposed iron core of a small planet that failed to form during the earliest days of the solar system. But new research suggests that the asteroid might not be as metallic or dense as once thought, and hints at a much different origin story. Scientists are interested in 16 Psyche because if its presumed origins are true, it would provide an opportunity to study an exposed planetary core up close. NASA is scheduled to launch its Psyche mission in 2022 and arrive at the asteroid in 2026. New research proposes 16 Psyche is 82.5% metal, 7% low-iron pyroxene and 10.5% carbonaceous chondrite that was likely delivered by impacts from other asteroids. It is estimated that 16 Psyche's bulk density -- also known as porosity, which refers to how much empty space is found within its body -- is around 35%. These estimates differ from past analyses of 16 Psyche's composition that led researchers to estimate it could contain as much as 95% metal and be much denser. Rather than being an intact exposed core of an early planet, it might actually be closer to a rubble pile, similar to another thoroughly studied asteroid - Bennu. A sample from Bennu's surface is now making its way back to Earth. Asteroid 16 Psyche is about the size of Massachusetts, and scientists estimate it contains about 1% of all asteroid belt material. First spotted by an Italian astronomer in 1852, it was the 16th asteroid ever discovered.

Asteroid 16 Psyche has been estimated to been worth $10,000 quadrillion but the new findings could slightly devalue the iron-rich asteroid. The other well-studied asteroid, Bennu, contains a lot of carbonaceous chondrite material and has porosity of over 50%, which is a classic characteristic of a rubble pile. Such high porosity is common for relatively small and low-mass objects such as Bennu -- which is only as large as the Empire State Building -- because a weak gravitational field prevents the object's rocks and boulders from being packed together too tightly. But for an object the size of 16 Psyche to be so porous is unexpected. Past estimates of 16 Psyche's composition were done by analyzing the sunlight reflected off its surface. The pattern of light matched that of other metallic objects. The researchers also believe the carbonaceous material on 16 Psyche's surface is rich in water, so they will next work to merge data from ground-based telescopes and spacecraft missions to other asteroids to help determine the amount of water present.

VENUS' TECTONICS REVEAL GEOLOGICAL SECRETS :
North Carolina State University

A new analysis of Venus' surface shows evidence of tectonic motion in the form of crustal blocks that have jostled against each other like broken chunks of pack ice. The movement of these blocks could indicate that Venus is still geologically active and give scientists insight into both exoplanet tectonics and the earliest tectonic activity on Earth. The finding is important because Venus has long been assumed to have an immobile solid outer shell, or lithosphere, just like Mars or Earth's moon. In contrast, Earth's lithosphere is broken into tectonic plates, which slide against, apart from, and underneath each other on top of a hot, weaker mantle layer. An international group of researchers used radar images from NASA's Magellan mission to map the surface of Venus. In examining the extensive Venusian lowlands that make up most of the planet surface, they saw areas where large blocks of the lithosphere seem to have moved: pulling apart, pushing together, rotating and sliding past each other like broken pack ice over a frozen lake. The team created a computer model of this deformation, and found that sluggish motion of the planet's interior can account for the style of tectonics seen at the surface. These observations tell us that interior motion is driving surface deformation on Venus, in a similar way to what happens on Earth. Plate tectonics on Earth are driven by convection in the mantle. The mantle is hot or cold in different places, it moves, and some of that motion transfers to Earth's surface in the form of plate movement. A variation on that theme seems to be playing out on Venus as well. It's not plate tectonics like on Earth -- there aren't huge mountain ranges being created here, or giant subduction systems -- but it is evidence of deformation due to interior mantle flow, which hasn't been demonstrated on a global scale before.

The deformation associated with these crustal blocks could also indicate that Venus is still geologically active. We know that much of Venus has been volcanically resurfaced over time, so some parts of the planet might be really young, geologically speaking. But several of the jostling blocks have formed in and deformed these young lava plains, which means that the lithosphere fragmented after those plains were laid down. This gives us reason to think that some of these blocks may have moved geologically very recently -- perhaps even up to today. The researchers are optimistic that Venus' newly recognized "pack ice" pattern could offer clues to understanding tectonic deformation on planets outside of our solar system, as well as on a much younger Earth. The thickness of a planet's lithosphere depends mainly upon how hot it is, both in the interior and on the surface. Heat flow from the young Earth's interior was up to three times greater than it is now, so its lithosphere may have been similar to what we see on Venus today: not thick enough to form plates that subduct, but thick enough to have fragmented into blocks that pushed, pulled, and jostled.

BETELGEUSE'S BRIGHTNESS DIP SOLVED
ESO

When Betelgeuse, a bright orange star in the constellation of Orion, became visibly darker in late 2019 and early 2020, the astronomy community was puzzled. A team of astronomers have now published new images of the star's surface, taken using the European Southern Observatory's Very Large Telescope (ESO's VLT), that clearly show how its brightness changed. The new research reveals that the star was partially concealed by a cloud of dust, a discovery that solves the mystery of the "Great Dimming" of Betelgeuse. Betelgeuse's dip in brightness -- a change noticeable even to the naked eye -- led astronomers to point ESO's VLT towards the star in late 2019. An image from December 2019, when compared to an earlier image taken in January of the same year, showed that the stellar surface was significantly darker, especially in the southern region. But the astronomers weren't sure why. The team continued observing the star during its Great Dimming, capturing two other never-before-seen images in January 2020 and March 2020. By April 2020, the star had returned to its normal brightness. In their new study, the team revealed that the mysterious dimming was caused by a dusty veil shading the star, which in turn was the result of a drop in temperature on Betelgeuse's stellar surface. Betelgeuse's surface regularly changes as giant bubbles of gas move, shrink and swell within the star. The team concludes that some time before the Great Dimming, the star ejected a large gas bubble that moved away from it. When a patch of the surface cooled down shortly after, that temperature decrease was enough for the gas to condense into solid dust. Rather than just the result of a dusty outburst, there was some speculation online that Betelgeuse's drop in brightness could signal its imminent death in a spectacular supernova explosion. A supernova hasn't been observed in our galaxy since the 17th century, so present-day astronomers aren't entirely sure what to expect from a star in the lead-up to such an event. However, this new research confirms that Betelgeuse's Great Dimming was not an early sign that the star was heading towards its dramatic fate.

DARK MATTER SLOWING SPIN OF MILKY WAY'S GALACTIC BAR
University College London

The spin of the Milky Way's galactic bar, which is made up of billions of clustered stars, has slowed by about a quarter since its formation, according to a new study. For 30 years, astrophysicists have predicted such a slowdown, but this is the first time it has been measured. The researchers say it gives a new type of insight into the nature of dark matter, which acts like a counterweight slowing the spin. In the study, researchers analysed Gaia space telescope observations of a large group of stars, the Hercules stream, which are in resonance with the bar -- that is, they revolve around the galaxy at the same rate as the bar's spin. These stars are gravitationally trapped by the spinning bar. The same phenomenon occurs with Jupiter's Trojan and Greek asteroids, which orbit Jupiter's Lagrange points (ahead and behind Jupiter). If the bar's spin slows down, these stars would be expected to move further out in the galaxy, keeping their orbital period matched to that of the bar's spin. The researchers found that the stars in the stream carry a chemical fingerprint -- they are richer in heavier elements (called metals in astronomy), proving that they have travelled away from the galactic centre, where stars and star-forming gas are about 10 times as rich in metals compared to the outer galaxy. Using this data, the team inferred that the bar -- made up of billions of stars and trillions of solar masses -- had slowed down its spin by at least 24% since it first formed.

The Milky Way, like other galaxies, is thought to be embedded in a 'halo' of dark matter that extends well beyond its visible edge. Dark matter is invisible and its nature is unknown, but its existence is inferred from galaxies behaving as if they were shrouded in significantly more mass than we can see. There is thought to be about five times as much dark matter in the Universe as ordinary, visible matter. Alternative gravity theories such as modified Newtonian dynamics reject the idea of dark matter, instead seeking to explain discrepancies by tweaking Einstein's theory of general relativity. The Milky Way is a barred spiral galaxy, with a thick bar of stars in the middle and spiral arms extending through the disc outside the bar. The bar rotates in the same direction as the galaxy.

GIANT 'BLINKING' STAR TOWARDS CENTRE OF MILKY WAY
University of Cambridge

An international team of astronomers observed the star, VVV-WIT-08, decreasing in brightness by a factor of 30, so that it nearly disappeared from the sky. While many stars change in brightness because they pulsate or are eclipsed by another star in a binary system, it's exceptionally rare for a star to become fainter over a period of several months and then brighten again. The researchers believe that VVV-WIT-08 may belong to a new class of 'blinking giant' binary star system, where a giant star -- 100 times larger than the Sun -- is eclipsed once every few decades by an as-yet unseen orbital companion. The companion, which may be another star or a planet, is surrounded by an opaque disc, which covers the giant star, causing it to disappear and reappear in the sky. Since the star is located in a dense region of the Milky Way, the researchers considered whether some unknown dark object could have simply drifted in front of the giant star by chance. However, simulations showed that there would have to be an implausibly large number of dark bodies floating around the Galaxy for this scenario to be likely. One other star system of this sort has been known for a long time. The giant star Epsilon Aurigae is partly eclipsed by a huge disc of dust every 27 years, but only dims by about 50%. A second example, TYC 2505-672-1, was found a few years ago, and holds the current record for the eclipsing binary star system with the longest orbital period -- 69 years -- a record for which VVV-WIT-08 is currently a contender. The UK-based team has also found two more of these peculiar giant stars in addition to VVV-WIT-08, suggesting that these may be a new class of 'blinking giant' stars for astronomers to investigate.

VVV-WIT-08 was found by the VISTA Variables in the Via Lactea survey (VVV), a project using the British-built VISTA telescope in Chile and operated by the European Southern Observatory, that has been observing the same one billion stars for nearly a decade to search for examples with varying brightness in the infrared part of the spectrum. While VVV-WIT-08 was discovered using VVV data, the dimming of the star was also observed by the Optical Gravitational Lensing Experiment (OGLE), a long-running observation campaign run by the University of Warsaw. OGLE makes more frequent observations, but closer to the visible part of the spectrum. These frequent observations were key for modelling VVV-WIT-08, and they showed that the giant star dimmed by the same amount in both the visible and infrared light. There now appear to be around half a dozen potential known star systems of this type, containing giant stars and large opaque discs.

SURVEY OF 'NURSERIES' WHERE STARS ARE BORN
Ohio State University

Over the past five years, an international team of researchers has conducted the first systematic survey of "stellar nurseries" across our part of the Universe, charting the more than 100,000 of these nurseries across more than 90 nearby galaxies and providing new insights into the origins of stars. Every star in the sky, including our own Sun, was born in one of these stellar nurseries. These nurseries are responsible for building galaxies and making planets, and they're just an essential part in the story of how we got here. But this is really the first time we have a complete view of these stellar nurseries across the whole nearby Universe. The project is called PHANGS-ALMA, and the research was possible thanks to the ALMA telescope array high in the Andes mountains in Chile. PHANGS-ALMA can use ALMA to take pictures of many galaxies, and these pictures are as sharp and detailed as those taken by optical telescopes. The survey has expanded the amount of data on stellar nurseries by more than tenfold. That has given astronomers a much more accurate perspective of what these nurseries are like across our corner of the Universe. Based on these measurements, astronomers have found that stellar nurseries are surprisingly diverse across galaxies, live only a relatively short time in astronomical terms, and are not very efficient at making stars. The diversity of these stellar nurseries came as something of a surprise. For a long time, conventional wisdom among astronomers was that all stellar nurseries looked more or less the same. But with this survey we can see that this is really not the case. While there are some similarities, the nature and appearance of these nurseries change within and among galaxies, just like cities or trees may vary in important ways as you go from place to place across the world. For example, nurseries in larger galaxies, and those in the centre of galaxies, tend to be denser and more massive, and much more turbulent. Star formation is much more violent in these clouds, findings suggest. So the properties of these nurseries and even their ability to make stars seem to depend on the galaxies they live in.

Results from the survey also showed that these stellar nurseries live for only 10 to 30 million years, which is a relatively short time in astronomical terms. And the team used the same measurements to gauge how efficiently these stellar nurseries turned their gas and dust into stars -- and it turned out they weren't that efficient. This survey is allowing us to build a much more complete picture of the life cycle of these regions, and we're finding they are short-lived and inefficient. It's not random chance destroying these nurseries, but the new stars that they make. The radiation and heat that come out of these young stars begins to disperse and dissolve the clouds, eventually destroying them before they can convert most of their mass.

HUBBLE CONFIRMS GALAXIES LACKING DARK MATTER
Institute for Advanced Study

The most accurate distance measurement yet of ultra-diffuse galaxy (UDG) NGC1052-DF2 (DF2) confirms beyond any shadow of a doubt that it is lacking in dark matter. The newly measured distance of 22.1 +/-1.2 megaparsecs was obtained by an international team of researchers. The results are based on 40 orbits of NASA's Hubble Space Telescope, with imaging by the Advanced Camera for Surveys and a "tip of the red giant branch" (TRGB) analysis, the gold standard for such refined measurements. In 2019, the team published results measuring the distance to neighbouring UDG NGC1052-DF4 (DF4) based on 12 Hubble orbits and TRGB analysis, which provided compelling evidence of missing dark matter. This preferred method expands on the team's 2018 studies that relied on "surface brightness fluctuations" to gauge distance. Both galaxies were discovered with the Dragonfly Telephoto Array at the New Mexico Skies observatory. In addition to confirming earlier distance findings, the Hubble results indicated that the galaxies were located slightly farther away than previously thought, strengthening the case that they contain little to no dark matter. If DF2 were closer to Earth, as some astronomers claim, it would be intrinsically fainter and less massive, and the galaxy would need dark matter to account for the observed effects of the total mass. Dark matter is widely considered to be an essential ingredient of galaxies, but this study lends further evidence that its presence may not be inevitable. While dark matter has yet to be directly observed, its gravitational influence is like a glue that holds galaxies together and governs the motion of visible matter. In the case of DF2 and DF4, researchers were able to account for the motion of stars based on stellar mass alone, suggesting a lack or absence of dark matter. Ironically, the detection of galaxies deficient in dark matter will likely help to reveal its puzzling nature and provide new insights into galactic evolution.

While DF2 and DF4 are both comparable in size to the Milky Way galaxy, their total masses are only about one percent of the Milky Way's mass. These ultra-diffuse galaxies were also found to have a large population of especially luminous globular clusters. This research has generated a great deal of scholarly interest, as well as energetic debate among proponents of alternative theories to dark matter, such as Modified Newtonian dynamics (MOND). However, with the team's most recent findings -- including the relative distances of the two UDGs to NGC1052 -- such alternative theories seem less likely. Additionally, there is now little uncertainty in the team's distance measurements given the use of the TRGB method. Based on fundamental physics, this method depends on the observation of red giant stars that emit a flash after burning through their helium supply that always happens at the same brightness. Moving forward, researchers will continue to hunt for more of these oddball galaxies, while considering a number of questions such as: How are UDGs formed? What do they tell us about standard cosmological models? How common are these galaxies, and what other unique properties do they have? It will take uncovering many more dark matter-less galaxies to resolve these mysteries and the ultimate question of what dark matter really is.

'CHANGING-LOOK' BLAZAR DISCOVERED
University of Oklahoma

Astronomers have discovered a "changing-look" blazar -- a powerful active galactic nucleus powered by supermassive black hole at the centre of a galaxy. Blazars appear as parallel rays of light or particles, or jets, pointing to observers and radiating across all wavelengths of the electromagnetic spectrum. These jets span distances on the million light-year scales and are known to impact the evolution of the galaxy and galaxy cluster in which they reside via the radiation. These features make blazars ideal environments in which to study the physics of jets and their role in galaxy evolution. They are a unique kind of AGN with very powerful jets. Jets are a radio mode of feedback and because of their scales, they penetrate the galaxy into their large-scale environment. The origin of these jets and processes driving the radiation are not well-known. Thus, studying blazars allows us to understand these jets better and how they are connected to other components of the AGN, like the accretion disk. These jets can heat up and displace gas in their environment affecting, for example, the star formation in the galaxy. The team's research highlights the results of a campaign to investigate the evolution of a blazar known as B2 1420+32. At the end of 2017, this blazar exhibited a huge optical flare, a phenomenon captured by the All Sky Automated Survey for SuperNovae telescope network. The team followed this up by observing the evolution of its spectrum and light curve over the next two years and also retrieved archival data available for this object. The campaign, with data spanning over a decade, has yielded some most exciting results. There is dramatic variability in the spectrum and multiple transformations between the two blazar sub-classes for the first time for a blazar, thus giving it the name 'changing-look' blazar.

The team concluded that this behaviour is caused by the dramatic continuum flux changes, which confirm a long-proposed theory that separates blazars into two major categories. In addition, astronomers see several very large multiband flares in the optical and gamma-ray bands on different timescales and new spectral features. Such extreme variability and the spectral features demand dedicated searches for more such blazars, which will allow them to utilize the dramatic spectral changes observed to reveal AGN/jet physics, including how dust particles around supermassive black holes are destructed by the tremendous radiation from the central engine and how energy from a relativistic jet is transferred into the dust clouds, providing a new channel linking the evolution of the supermassive black hole with its host galaxy. The team is very excited by the results of discovering a changing-look blazar that transforms itself not once, but three times, between its two sub-classes, from the dramatic changes in its continuum emission. These results open the door to more such studies of highly variable blazars and their importance in understanding AGN physics.

CHIME DISCOVERS OVER 500 FAST RADIO BURSTS
Massachusetts Institute of Technology

To catch sight of a fast radio burst is to be extremely lucky in where and when you point your radio dish. Fast radio bursts, or FRBs, are oddly bright flashes of light, registering in the radio band of the electromagnetic spectrum, that blaze for a few milliseconds before vanishing without a trace. These brief and mysterious beacons have been spotted in various and distant parts of the Universe, as well as in our own galaxy. Their origins are unknown, and their appearance is unpredictable. Since the first was discovered in 2007, radio astronomers have only caught sight of around 140 bursts in their telescopes. Now, a large stationary radio telescope in British Columbia has nearly quadrupled the number of fast radio bursts discovered to date. The telescope, known as CHIME, for the Canadian Hydrogen Intensity Mapping Experiment, has detected 535 new fast radio bursts during its first year of operation, between 2018 and 2019. Scientists with the CHIME Collaboration, including researchers at MIT, have assembled the new signals in the telescope's first FRB catalogue, which they will present this week at the American Astronomical Society Meeting. The new catalogue significantly expands the current library of known FRBs, and is already yielding clues as to their properties. For instance, the newly discovered bursts appear to fall in two distinct classes: those that repeat, and those that don't. Scientists identified 18 FRB sources that burst repeatedly, while the rest appear to be one-offs. The repeaters also look different, with each burst lasting slightly longer and emitting more focused radio frequencies than bursts from single, non-repeating FRBs. These observations strongly suggest that repeaters and one-offs arise from separate mechanisms and astrophysical sources. With more observations, astronomers hope soon to pin down the extreme origins of these curiously bright signals. CHIME comprises four massive parabolic radio antennas, roughly the size and shape of snowboarding half-pipes, located at the Dominion Radio Astrophysical Observatory in British Columbia, Canada. CHIME receives radio signals each day from half of the sky as the Earth rotates. While most radio astronomy is done by swivelling a large dish to focus light from different parts of the sky, CHIME stares, motionless, at the sky, and focuses incoming signals using a correlator -- a powerful digital signalling processor that can work through huge amounts of data, at a rate of about 7 terabits per second, equivalent to a few percent of the world's internet traffic.

Over the first year of operation, CHIME detected 535 new fast radio bursts. When the scientists mapped their locations, they found the bursts were evenly distributed in space, seeming to arise from any and all parts of the sky. From the FRBs that CHIME was able to detect, the scientists calculated that fast radio bursts, bright enough to be seen by a telescope like CHIME, occur at a rate of about 9,000 per day across the entire sky -- the most precise estimate of FRBs overall rate to date. As radio waves travel across space, any interstellar gas, or plasma, along the way can distort or disperse the wave's properties and trajectory. The degree to which a radio wave is dispersed can give clues to how much gas it passed through, and possibly how much distance it has travelled from its source. For each of the 535 FRBs that CHIME detected, astronomers measured its dispersion, and found that most bursts likely originated from far-off sources within distant galaxies. The fact that the bursts were bright enough to be detected by CHIME suggests that they must have been produced by extremely energetic sources. As the telescope detects more FRBs, scientists hope to pin down exactly what kind of exotic phenomena could generate such ultrabright, ultrafast signals. Scientists also plan to use the bursts, and their dispersion estimates, to map the distribution of gas throughout the Universe. Each FRB gives us some information of how far they've propagated and how much gas they've propagated through. With large numbers of FRBs, we can hopefully figure out how gas and matter are distributed on very large scales in the universe. So, alongside the mystery of what FRBs are themselves, there's also the exciting potential for FRBs as powerful cosmological probes in the future.

PROBLEMS WITH HUBBLE SPACE TELESCOPE
Physics.org

The Hubble Space Telescope, which has been peering into the Universe for more than 30 years, has been down for the past week. The problem is a payload computer that stopped working the US space agency said. It insisted the telescope itself and scientific instruments that accompany it are "in good health." NASA said initial evidence pointed to a degrading computer memory module as the source of the computer problem. An attempt to switch to a back-up memory module also failed. The technology for the payload computer dates back to the 1980s, and it was replaced during maintenance work in 2009. Launched in 1990, the Hubble Space Telescope revolutionized the world of astronomy and changed our vision of the Universe as it sent back images of the solar system, the Milky Way and distant galaxies. NASA plans to continue its efforts to resolve the problem. 





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
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Astronomy Group / The Night Sky in July 2021
July 04, 2021, 01:34:26 pm
The Night Sky in July 2021
Hello everyone here is the latest monthly night sky tips for July 2021. sorry it is a little late, but I was awy in Nottingham last weekend. All the bright planets make an appearance this month. While Mars is as dim as it gets, the Red Planet appears alongside Venus and the Moon in the evening sky for a photogenic apparition. Jupiter and Saturn rise after midnight in the southeast, each planet slowly brightening and growing on its way to opposition next month. They are both spectacular in a telescope right now. And little Mercury makes a good apparition in the eastern morning twilight before the sun rises. While it's mostly planets this month, don't forget about the Milky Way emerging in the darkening east-south-eastern sky. 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...

The Night Sky in July 2021.pdf
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Science and Technology / Housing problem?
June 24, 2021, 06:48:24 pm
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General Chatty Stuff / Anyone flying this year?
June 22, 2021, 05:51:34 pm
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THE WOOD - STREAMING ONLINE
SHOWING FROM
TUE 22 JUN - SAT 03 JUL 2021
PRICE:
PAY WHAT YOU CAN
Torch Theatre Company presents: THE WOOD

WRITTEN BY OWEN THOMAS • DIRECTED BY PETER DORAN  BASED ON AN IDEA BY IFAN HUW DAFYDD

 "A tale of friendship, love and sacrifice set against the backdrop of a world in flames..."
From acclaimed Welsh playwright Owen Thomas, writer of the award-winning Grav, comes a digitally streamed version of the stage play originally written to commemorate the centenary of the end of World War I. Inspired by a true story.  Originally toured to packed out theatres across Wales in 2018, The Wood is a powerful, moving piece of theatre that lends itself beautifully to the screen. The streamed version reunites the original cast that toured in 2018; Ifan Huw Dafydd as Dan and Gwydion Rhys as Billy, alongside the original creative team; Director Peter Doran and Designer Sean Crowley.

The Wood was recorded on stage as live at the Torch Theatre, Milford Haven, under Covid-19 guidelines during lockdown 2021.

To book click here
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Treffgarne Rocks Pembrokeshire - a waxing crescent moon greets Venus as dusk falls!

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THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 543 2021 June 13

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_spa1/join-the-spa-now/

EUROPA'S INTERIOR HOT ENOUGH TO FUEL SEAFLOOR VOLCANOES
NASA

Jupiter's moon Europa has an icy crust covering a vast, global ocean. The rocky layer underneath may be hot enough to melt, leading to undersea volcanoes.  New research shows that volcanic activity may have occurred on the seafloor of Jupiter's moon Europa in the recent past - and may still be happening. The upcoming Europa Clipper mission, targeting a 2024 launch, will swoop close to the icy moon and take measurements that may shed light on the recent findings. Scientists have strong evidence that Europa harbours an enormous ocean between its icy crust and rocky interior. The new work shows how the moon may have enough internal heat to partially melt this rocky layer, a process that could feed volcanoes on the ocean floor. The recent 3D modelling of how this internal heat is produced and transferred is the most detailed and thorough examination yet of the effect this interior heating has on the moon. The key to Europa's rocky mantle being hot enough to melt lies with the
massive gravitational pull Jupiter has on its moons. As Europa revolves around the gas giant, the icy moon's interior flexes. The flexing forces energy into the moon's interior, which then seeps out as heat (think of how repeatedly bending a paperclip generates heat). The more the moon's interior flexes, the more heat is generated.

The research, published recently in Geophysical Research Letters, models in detail how Europa's rocky part may flex and heat under the pull of Jupiter's gravity. It shows where heat dissipates and how it melts that rocky mantle, increasing the likelihood of volcanoes on the seafloor.  Underwater volcanoes, if present, could power hydrothermal systems like those that fuel life at the bottom of Earth's oceans. On Earth, when seawater comes into contact with hot magma, the interaction results in chemical energy. And it is chemical energy from these hydrothermal systems, rather than from sunlight, that helps support life deep in our own oceans. Volcanic activity on Europa's seafloor would be one way to support a potential habitable environment in that moon's ocean.

PREVIOUSLY UNKNOWN ENERGY SOURCE AT CENTRE OF MILKY WAY
University of Massachusetts Amherst

New research reveals, with unprecedented clarity, details of violent phenomena in the centre of our galaxy. The images, published recently in Monthly Notices of the Royal Astronomical Society, which hints at a previously unknown interstellar mechanism that may govern the energy flow and potentially the evolution of the Milky Way. Astronomers know the centres of galaxies are where the action is and play an enormous role in their evolution. And yet, whatever has happened in the centre of our own galaxy is hard to study, despite its relative proximity to Earth, because it is obscured by a dense fog of gas and dust. Researchers simply can't see the centre, even with the Hubble Space Telescope. However, astronomers used the Chandra X-Ray Observatory, which "sees" X-rays, rather than the rays of visible light that we perceive with our own eyes. These X-rays are capable of penetrating the obscuring fog -- and the results are stunning. The findings give the clearest picture yet of a pair of X-ray-emitting plumes that are emerging from the region near the massive black hole lying at the centre of our galaxy. Even more intriguing is the discovery of an X-ray thread called G0.17-0.41, located near the southern plume. This thread reveals a new phenomenon - it is evidence of an ongoing magnetic field reconnection event. The thread probably represents "only the tip of the reconnection iceberg."

A magnetic field reconnection event is what happens when two opposing magnetic fields are forced together and combine with one another, releasing an enormous amount of energy. It's a violent process and is known to be responsible for such well-known phenomena as solar flares, which produce space weather powerful enough to disrupt power grids and communications systems here on Earth. They also produce the spectacular Northern Lights. Scientists now think that magnetic reconnection also occurs in interstellar space and tends to take place at the outer boundaries of the expanding plumes driven out of our galaxy's centre. What is the total amount of energy outflow at the centre of the galaxy? How is it produced and transported? And how does it regulate the galactic ecosystem? These are the fundamental questions whose answers will help to unlock the history of our galaxy. Though much work remains to be done, the new map points the way. For more information, including additional images and video, visit the Chandra X-Ray Observatory's Galactic Center website.

PROBING INTO ORIGINS OF COSMIC RAYS
American Institute of Physics

Cosmic rays are high-energy atomic particles continually bombarding Earth's surface at nearly the speed of light. Our planet's magnetic field shields the surface from most of the radiation generated by these particles. Still, cosmic rays can cause electronic malfunctions and are the leading concern in planning for space missions. Researchers know cosmic rays originate from the multitude of stars in the Milky Way, including our Sun, and other galaxies. The difficulty is tracing the particles to specific sources, because the turbulence of interstellar gas, plasma, and dust causes them to scatter and re-scatter in different directions. Researchers developed a simulation model to better understand these and other cosmic ray transport characteristics, with the goal of developing algorithms to enhance existing detection techniques. Brownian motion theory is generally employed to study cosmic ray trajectories. Much like the random motion of pollen particles in a pond, collisions between cosmic rays within fluctuating magnetic fields cause the particles to propel in different directions. But this classic diffusion approach does not adequately address the different propagation rates affected by diverse interstellar environments and long spells of cosmic voids. Particles can become trapped for a time in magnetic fields, which slow them down, while others are thrust into higher speeds through star explosions.

To address the complex nature of cosmic ray travel, the researchers use a stochastic scattering model, a collection of random variables that evolve over time. The model is based on geometric Brownian motion, a classic diffusion theory combined with a slight trajectory drift in one direction. In their first experiment, they simulated cosmic rays moving through interstellar space and interacting with localized magnetized clouds, represented as tubes. The rays travel undisturbed over a long period of time. They are interrupted by chaotic interaction with the magnetized clouds, resulting in some rays reemitting in random directions and others remaining trapped. Monte Carlo numerical analysis, based on repeated random sampling, revealed ranges of density and reemission strengths of the interstellar magnetic clouds, leading to skewed, or heavy-tailed, distributions of the propagating cosmic rays. The analysis denotes marked superdiffusive behaviour. The model's predictions agree well with known transport properties in complex interstellar media.

DARK MATTER REVEALS BRIDGES BETWEEN GALAXIES
Penn State

A new map of dark matter in the local Universe reveals several previously undiscovered filamentary structures connecting galaxies. The map, developed using machine learning by researchers, could enable studies about the nature of dark matter as well as about the history and future of our local Universe. Dark matter is an elusive substance that makes up 80% of the Universe. It also provides the skeleton for what cosmologists call the cosmic web, the large-scale structure of the universe that, due to its gravitational influence, dictates the motion of galaxies and other cosmic material. However, the distribution of local dark matter is currently unknown because it cannot be measured directly. Researchers must instead infer its distribution based on its gravitational influence on other objects in the universe, like galaxies. Ironically, it's easier to study the distribution of dark matter much further away because it reflects the very distant past, which is much less complex. Over time, as the large-scale structure of the Universe has grown, the complexity of the Universe has increased, so it is inherently harder to make measurements about dark matter locally. Previous attempts to map the cosmic web started with a model of the early Universe and then simulated the evolution of the model over billions of years. However, this method is computationally intensive and so far has not been able to produce results detailed enough to see the local Universe. In the new study, the researchers took a completely different approach, using machine learning to build a model that uses information about the distribution and motion of galaxies to predict the distribution of dark matter.

The researchers built and trained their model using a large set of galaxy simulations, called Illustris-TNG, which includes galaxies, gasses, other visible matter, as well as dark matter. The team specifically selected simulated galaxies comparable to those in the Milky Way and ultimately identified which properties of galaxies are needed to predict the dark matter distribution. When given certain information, the model can essentially fill in the gaps based on what it has looked at before. The map from the models doesn't perfectly fit the simulation data, but researchers can still reconstruct very detailed structures. They found that including the motion of galaxies -- their radial peculiar velocities -- in addition to their distribution drastically enhanced the quality of the map and allowed them to see these details. The research team then applied their model to real data from the local Universe from the Cosmicflow-3 galaxy catalogue. The catalogue contains comprehensive data about the distribution and movement of more than 17 thousand galaxies in the vicinity of the Milky Way -- within 200 megaparsecs. The map successively reproduced known prominent structures in the local Universe, including the "local sheet" -- a region of space containing the Milky Way, nearby galaxies in the "local group," and galaxies in the Virgo cluster -- and the "local void" -- a relatively empty region of space next to the local group. Additionally, it identified several new structures that require further investigation, including smaller filamentary structures that connect galaxies. Having a local map of the cosmic web opens up a new chapter of cosmological study such as how the distribution of dark matter relates to other emission data, which will help us understand the nature of dark matter. And we can study these filamentary structures directly, these hidden bridges between galaxies. For example, it has been suggested that the Milky Way and Andromeda galaxies may be slowly moving toward each other, but whether they may collide in many billions of years remains unclear. Studying the dark matter filaments connecting the two galaxies could provide important insights into their future.

HUNT FOR HUM OF GRAVITATIONAL WAVES
Australian National University

The hunt for the never before heard "hum" of gravitational waves caused by neutron stars has just got a lot easier, thanks to an international team of researchers. Gravitational waves have only been detected from black holes and neutron stars colliding, major cosmic events that cause huge bursts that ripple through space and time. The research team are now turning their eagle eye to spinning neutron stars to detect the waves. Unlike the massive bursts caused by black holes or neutron stars colliding, the researchers say single spinning neutron stars have a bulge or "mountain" only a few millimetres high, which may produce a steady constant stream or "hum" of gravitational waves. The researchers are using their methods that detected gravitational waves for the first time in 2015 to capture this steady soundtrack of the stars over the thunderous noise of massive black holes and dense neutron stars colliding. They say it's like trying to capture the squeak of a mouse in the middle of a stampeding herd of elephants. If successful, it would be the first detection of a gravitational wave event that didn't involve the collision of massive objects like black holes or neutron stars. The collision of dense neutron stars sends a "burst" of gravitational waves rippling through the Universe. Neutron stars are mystery objects and astronomers don't really understand what they are made up of, or how many types of them exist. But what is known is that when they collide, they send incredible bursts of gravitational waves across the Universe. In contrast, the gentle hum of a spinning neutron star is very faint and almost impossible to detect. If astronomers can manage to detect this hum, they will be able to look deep into the heart of a neutron star and unlock its secrets. Neutron stars represent the densest form of matter in the Universe before a black hole will form. Searching for their gravitational waves allows us to probe nuclear matter states that simply can't be produced in laboratories on Earth.

TWO NEW MISSIONS TO VENUS
NASA

Part of NASA's Discovery Program, the missions aim to understand how Venus became an inferno-like world when it has so many other characteristics similar to ours - and may have been the first habitable world in the solar system, complete with an ocean and Earth-like climate. These investigations are the final selections from four mission concepts NASA picked in February 2020 as part of the agency's Discovery 2019 competition. Following a competitive, peer-review process, the two missions were chosen based on their potential scientific value and the feasibility of development plans. The project teams will now work to finalize their requirements, designs, and development plans. NASA is awarding approximately $500 million per mission for development. Each is expected to launch in the 2028-2030 timeframe. The selected missions are: DAVINCI+ (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging). DAVINCI+ will measure the composition of Venus' atmosphere to understand how it formed and evolved, as well as determine whether the planet ever had an ocean. The mission consists of a descent sphere that will plunge through the planet's thick atmosphere, making precise measurements of noble gases and other elements to understand why Venus' atmosphere is a runaway hothouse compared the Earth's. In addition, DAVINCI+ will return the first high resolution pictures of the unique geological features on Venus known as "tesserae," which may be comparable to Earth's continents, suggesting that Venus has plate tectonics. This would be the first U.S.-led mission to Venus' atmosphere since 1978, and the results from DAVINCI+ could reshape our understanding of terrestrial planet formation in our solar system and beyond.

VERITAS (Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy) VERITAS will map Venus' surface to determine the planet's geologic history and understand why it developed so differently than Earth. Orbiting Venus with a synthetic aperture radar, VERITAS will chart surface elevations over nearly the entire planet to create 3D reconstructions of topography and confirm whether processes such as plate tectonics and volcanism are still active on Venus. VERITAS also will map infrared emissions from Venus' surface to map its rock type, which is largely unknown,and determine whether active volcanoes are releasing water vapour into the atmosphere.

FURTHER DELAY FOR JAMES WEBB TELESCOPE
ARS Technica

The James Webb Space Telescope won't launch as scheduled on Halloween this year--however, the delay may only be a few weeks. Last summer, NASA and the European Space Agency (ESA) set an October 31, 2021, launch date for the $10 billion telescope. The instrument, which is the largest science observatory ever placed into space, will launch on a European Ariane 5 rocket from a spaceport in French Guiana. Now, however, three considerations have pushed the launch into November or possibly early December. The telescope's director for launch services said that there are a "combination of different factors" to consider when setting a new launch date. These factors include shipment of the telescope, the readiness of the Ariane 5 rocket, and the readiness of the spaceport in South America as well. A new launch date will not be announced until later this summer or early autumn. NASA plans to ship the telescope to the launch site by boat late this summer. (NASA is keeping precise plans vague due to concerns about piracy at sea.) The launch campaign, which begins when the telescope arrives in French Guiana, requires 55 days. The rocket is also not ready. The Ariane 5 booster, a venerable rocket in service for more than 25 years, has been grounded since August 2020 due to a payload fairing issue. However, officials with Arianespace, which manages launch for the Ariane 5, said the fairing issue's cause has been diagnosed and addressed with a redesign. Two Ariane 5 launches are scheduled before Webb's launch to ensure that the fairing issue has been fixed. (Those launches are scheduled for July and August, but delays are possible.) Finally, there are concerns about the spaceport itself, where operations have been limited by COVID-19. Vaccines are not yet widely available in French Guiana, and officials have said that if virus activity worsens, it could further slow operations.

Bulletin compiled by Clive Down
16
Family History / LostCousins Newsletter
June 07, 2021, 10:52:01 am
Banging your head against a 'brick wall'?  Perhaps this newsletter will inspire you to change your tactics....

What makes a 'brick wall' crack?
Oldest 'brick wall' comes crashing down
Save 25% on Ancestry DNA in the UK ENDS 20TH JUNE
Don't just read the Masterclass.....
Exporting servants to Western Australia in the 1850s and 1890sScottish Roman Catholic registers online
Marriage registers: follow up
An amazing sequence of marriages and other chance discoveries
Adoption stories: forced to give up their child
The last veteran of Dunkirk and D-Day?
Get better results from your newspaper searches
What's available from your local library?
Royal Succession
Realising the potential of DNA: gene therapy
Probability and family history (part 2)
Peter's Tips

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

https://lostcousins.com/newsletters2/jun21news.htm
17
Pembrokeshire County Council is proposing to amend its Off Street parking order (car parks).

It follows a full review of the service, which was considered by Cabinet in March 2020 who agreed to proceed to consultation. This has been delayed until now because of Covid-19.

The review proposes that the parking service reaches a full cost recovery position (it currently runs at a loss) and also provides income for the following:
·                     protecting the future of public toilets situated in car parks
·                     providing additional street lighting in car parks
·                     increasing the budget for minor improvement works and general maintenance
·                     rolling out cashless parking payment machines

Some key proposed changes include:
·                     amending seasonal charges to all year charges
·                     increasing the cost of a coastal permit
·                     introducing a new maximum stay on Goodwick Bridge car park (the flags car park)

The consultation on the proposal (called a variation order) can be viewed here:
https://haveyoursay.pembrokeshire.gov.uk/proposed-variation-to-off-street-parking-places-order . The link also gives you access to a number of documents to assist in explaining the reasoning, as well as maps.

The deadline for comments is 16 June.

Feedback from the consultation will be incorporated into a report to Cabinet for their final decision.
18


Hywel Dda University Health Board (UHB) is asking the people of Carmarthenshire, Ceredigion and Pembrokeshire to help it further shape and deliver future services by taking part in a six-week engagement exercise.
The public is also being asked to nominate sites for a new hospital based four criteria:

The nominated site must be within the zone between and including St Clears in Carmarthenshire and Narberth in Pembrokeshire. This location is the most central to most of the population in the south of the Hywel Dda area.
The nominated site should be a minimum of 35 acres of reasonably developable land.
The nominated site should have realistic prospects of obtaining planning permission for a new hospital.
There should be appropriate transport infrastructure for a major hospital site.


FOR FULL DETAILS CLICK HERE
19
Astronomy Group / Night Sky in June 2021
June 02, 2021, 03:42:32 pm
Night Sky in June

A change of seasons arrives as stargazers in the southern hemisphere enjoy long nights to make up for cooling
temperatures, while northerners enjoy summer at the expense of much shorter nights! But there's plenty to see this month as Jupiter and Saturn grow in brightness and size, rising in the southeast after midnight. Mars slowly eases itself westwards towards the sun after more than a year in the night sky, but it goes out in style as it passes through the Beehive star cluster late in the month. Mercury is lost in the sun's glare for most of June. But Venus sits low and bright in the evening sky over the northwestern horizon after sunset at its most northerly declination of the year.

Here's what to see in the night (and day) sky this month..................SEE ATTACHMENT BELOW

The Night Sky in June 2021.pdf
20
THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 542 2021 May 30

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.

ALIEN RADIOACTIVE ELEMENT PROMPTS RETHINK
Australian National University

The first-ever discovery of an extraterrestrial radioactive isotope on Earth has scientists rethinking the origins of the elements on our planet. The tiny traces of plutonium-244 were found in ocean crust alongside radioactive iron-60. The two isotopes are evidence of violent cosmic events in the vicinity of Earth millions of years ago. Star explosions, or supernovae create many of the heavy elements in the periodic table, including those vital for human life, such as iron, potassium and iodine. To form even heavier elements, such as gold, uranium and plutonium it was thought that a more violent event may be needed, such as two neutron stars merging. However, a new study suggests a more complex picture. Any plutonium-244 and iron-60 that existed when the Earth formed from interstellar gas and dust over four billion years ago has long since decayed, so current traces of them must have originated from recent cosmic events in space. The dating of the sample confirms two or more supernova explosions occurred near Earth. The data could be the first evidence that supernovae do indeed produce plutonium-244. Or perhaps it was already in the interstellar medium before the supernova went off, and it was pushed across the solar system together with the supernova ejecta. The VEGA accelerator at Australian Nuclear Science and Technology Organisation, (ANSTO) in Sydney was used to identify the tiny traces of the plutonium-244.

HEAVY METAL VAPOURS FOUND IN COMETS
ESO

A new study using data from the European Southern Observatory's Very Large Telescope (ESO's VLT) has shown that iron and nickel exist in the atmospheres of comets throughout our Solar System, even those far from the Sun. A separate study who also used ESO data, reported that nickel vapour is also present in the icy interstellar comet 2I/Borisov. This is the first time heavy metals, usually associated with hot environments, have been found in the cold atmospheres of distant comets. Astronomers know that heavy metals exist in comets' dusty and rocky interiors. But, because solid metals don't usually "sublimate" (become gaseous) at low temperatures, they did not expect to find them in the atmospheres of cold comets that travel far from the Sun. Nickel and iron vapours have now even been detected in comets observed at more than 480 million kilometres from the Sun, more than three times the Earth-Sun distance. One team found iron and nickel in comets' atmospheres in approximately equal amounts. Material in our Solar System, for example that found in the Sun and in meteorites, usually contains about ten times more iron than nickel. This new result therefore has implications for astronomers' understanding of the early Solar System, though the team is still decoding what these are. While the Belgian team has been studying these "fossil" objects with ESO's VLT for nearly 20 years, they had not spotted the presence of nickel and iron in their atmospheres until now. The team used data from the Ultraviolet and Visual Echelle Spectrograph (UVES) instrument on ESO's VLT, which uses spectroscopy, to analyse the atmospheres of comets at different distances from the Sun. This technique allows astronomers to reveal the chemical makeup of cosmic objects: each chemical element leaves a unique signature -- a set of lines -- in the spectrum of the light from the objects. The team had spotted weak, unidentified spectral lines in their UVES data and on closer inspection noticed that they were signalling the presence of neutral atoms of iron and nickel. A reason why the heavy elements were difficult to identify is that they exist in very small amounts: the team estimates that for each 100 kg of water in the comets' atmospheres there is only 1 g of iron, and about the same amount of nickel.

Another remarkable study shows that heavy metals are also present in the atmosphere of the interstellar comet 2I/Borisov. A team in Poland observed this object, the first alien comet to visit our Solar System, using the X-shooter spectrograph on ESO's VLT when the comet flew by about a year and a half ago. They found that 2I/Borisov's cold atmosphere contains gaseous nickel. The finding is surprising because, before the two studies, gases with heavy metal atoms had only been observed in hot environments, such as in the atmospheres of ultra-hot exoplanets or evaporating comets that passed too close to the Sun. 2I/Borisov was observed when it was some 300 million kilometres away from the Sun, or about twice the Earth-Sun distance. Studying interstellar bodies in detail is fundamental to science because they carry invaluable information about the alien planetary systems they originate from. The two studies show that 2I/Borisov and Solar System comets have even more in common than previously thought.

STAR WILL COME WITHIN 24 LIGHT DAYS OF SUN
Universe Today

Within the Milky Way, there are an estimated 200 to 400 billion stars, all of which orbit around the centre of our galaxy in a coordinated cosmic dance. As they orbit, stars in the galactic disk (where our Sun is located) periodically shuffle about and get closer to one another. At times, this can have a drastic effect on the star that experience a close encounter, disrupting their systems and causing planets to be ejected. Knowing when stars will make a close encounter with our Solar System, and how it might shake-up objects within it, is therefore a concern to astronomers. Using data collected by the Gaia Observatory, two researchers with the Russian Academy of Sciences (RAS) determined that a handful of stars will be making close passes by our Solar System in the future, one of which will stray pretty close! The study relied on astrometric data from the Gaia mission's Early Data Release 3 (EDR3), which revealed kinematic characteristics of stars that are expected to pass within 3.26 light-years (1 Parsec) with the Solar System in the future. To start things off simple: our Solar System is composed of eight designated planets and several minor (aka. dwarf) planets orbiting our main sequence G-type yellow dwarf Sun, which is surrounded by outer ring of icy objects known as the Kuiper Belt. Beyond this, at a distance of roughly light-years from the Sun (0.5 parsecs), is a massive cloud of icy debris known as the Oort Cloud, which is where long-period comets originate.

These comets are generally the result of objects making close flybys with the Solar System and knocking objects loose, to the point that they periodically fly through Solar System and around the Sun before heading back out. The outer edge of the Oort Cloud is estimated to be 0.5 parsecs (1.6 light-years) from our Sun, which makes them particularly responsive to perturbations from a number of sources. For astronomers, the process of searching for stars that may have flown by our Solar System in the past (and which may pass us by in the future) began in the 1960s. The research has improved as more sophisticated instruments have become available, leading to more detailed catalogues on nearby celestial objects. In order to know which stars will make a close encounter, you need to know their distance and their three velocities. These consist the two properties of proper motion - right ascension, declination - and radial velocity. Once you have all that, you can conduct astrometry, which is the precise measurement of the positions and movements of stars and other celestial bodies. It was for this very purpose that the ESA's Hipparcos satellite (1989-1993) and Gaia Observatory (2013-present) were created. Thanks to the precise data they have provided, and the updated catalogues on millions of stars and other celestial objects, astronomers are able to determine which of them are likely to make a close encounter in the future.

In the end, one star, designated 4270814637616488064 in the Gaia EDR3 database, will be making a particularly close encounter a little over a million years from now. Better-known as Gliese 710 (HIP 89825), this variable K-type orange dwarf star is about 60% as massive as our Sun and located some 62 light years from Earth in the Serpens constellation. The showed that Gliese 710 would be making its close flyby 1.32 million years from now and would pass within 0.20 parsecs (0.65 light-years) of our Sun. So, assuming human beings (or their genetic progeny) are still living in the Solar System 2.32 million years from now, they will be treated to some added comet activity. This could pose some hazards, depending on the trajectories of these comets and the extent of human infrastructure in space. Or it could just mean more opportunities for backyard astronomy, or whatever the futuristic equivalent is.

NOVA BECOMES MUCH BRIGHTER
National Astronomical Observatory of Japan

A new star named V1405 Cas Nova which was discovered by an amateur astronomer in Japan has kept growing brighter over two months and it can be spotted with the naked eye now. Nakamura Yuji of the city of Kameyama in Mie Prefecture in central Japan found the star on March18. It is in the direction of Cassiopeia. It had increased its brightness 50-fold to a star magnitude level of five by May 9. Less than 20 new stars are found every year but most of them grow darker after growing brighter for several days. Experts say that it is rare that a new star grows brighter for a few months and becomes bright enough to be seen without a telescope. Astronomers believe that a major explosive phenomenon occurred on the surface of the star. It's a very rare and interesting phenomenon and researchers hope that many people will be encouraged to look up to the night sky and stars.

HOW AND WHEN MILKY WAY CAME TOGETHER
Ohio State University

New research provides the best evidence to date into the timing of how our early Milky Way came together, including the merger with a key satellite galaxy. Using relatively new methods in astronomy, the researchers were able to identify the most precise ages currently possible for a sample of about a hundred red giant stars in the galaxy. With this and other data, the researchers were able to show what was happening when the Milky Way merged with an orbiting satellite galaxy, known as Gaia-Enceladus, about 10 billion years ago. Evidence suggests that when the merger occurred, the Milky Way had already formed a large population of its own stars, Many of those "homemade" stars ended up in the thick disc in the middle of the galaxy, while most that were captured from Gaia-Enceladus are in the outer halo of the galaxy. The merging event with Gaia-Enceladus is thought to be one of the most important in the Milky Way's history, shaping how we observe it today. By calculating the age of the stars, the researchers were able to determine, for the first time, that the stars captured from Gaia-Enceladus have similar or slightly younger ages compared to the majority of stars that were born inside the Milky Way. A violent merger between two galaxies can't help but shake things up. Results showed that the merger changed the orbits of the stars already in the galaxy, making them more eccentric.

Astronomers compared the stars' movements to a dance, where the stars from the former Gaia-Enceladus move differently than those born within the Milky Way. The stars even "dress" differently, with stars from outside showing different chemical compositions from those born inside the Milky Way. The researchers used several different approaches and data sources to conduct their study. One way the researchers were able to get such precise ages of the stars was through the use of asteroseismology, a relatively new field that probes the internal structure of stars. Asteroseismologists study oscillations in stars, which are sound waves that ripple through their interiors. That allows us to get very precise ages for the stars, which are important in determining the chronology of when events happened in the early Milky Way. The study also used a spectroscopic survey, called APOGEE, which provides the chemical composition of stars -- another aid in determining their ages. Astronomers now intend to apply this approach to larger samples of stars, and to include even more subtle features of the frequency spectra. This will eventually lead to a much sharper view of the Milky Way's assembly history and evolution, creating a timeline of how our galaxy developed.

DOES THE MILKY WAY MOVE LIKE A SPINNING TOP? B:
Instituto de Astrofísica de Canarias (IAC)

An investigation questions one of the most interesting findings about the dynamics of the Milky Way in recent years: that the precession, or the wobble in the axis of rotation of the disc warp is incorrect. The Milky Way is a spiral galaxy, which means that it is composed, among other components, of a disc of stars, gas and dust, in which the spiral arms are contained. At first, it was thought that the disc was completely flat, but for some decades now it is known that the outermost part of the disc is distorted into what is called a "warp": in one direction it is twisted upwards, and in the opposite direction downwards. The stars, the gas, and the dust are all warped, and so are not in the same plane as the extended inner part of the disc, and an axis perpendicular to the planes of the warp defines their rotation. In 2020, an investigation announced the detection of the precession of the warp of the Milky Way disc, which means that the deformation in this outer region is not static, but that just like a spinning top the orientation of its axis is itself rotating with time. Furthermore, these researchers found that it was quicker than the theories predicted, a cycle every 600-700 million years, some three times the time it takes the Sun to travel once round the centre of the Galaxy. Precession is not a phenomenon which occurs only in galaxies, it also happens to our planet. As well as its annual revolution around the Sun, and its rotation period of 24 hours, the axis of the Earth precesses, which implies that the celestial pole is not always close to the present pole star, but that (as an example) 14,000 years ago it was close to the star Vega.

Now, a new study has taken into account the variation of the amplitude of the warp with the ages of the stars. The study concludes that, using the warp of the old stars whose velocities have been measured, it is possible that the precession can disappear, or at least become slower than what is presently believed. To arrive at this result the researchers have used data from the Gaia Mission of the European Space Agency (ESA), analysing the positions and velocities of hundreds of millions of stars in the outer disc. In previous studies it had not been noticed that the stars which are a few tens of millions of years old, such as the Cepheids, have a much larger warp than that of the stars visible with the Gaia mission, which are thousands of millions of years old. "This does not necessarily mean that the warp does not precess at all, it could do so, but much more slowly, and we are probably unable to measure this motion until we obtain better data.

36 DWARF GALAXIES HAD SIMULTANEOUS 'BABY BOOM'
Rutgers University

Three dozen dwarf galaxies far from each other had a simultaneous "baby boom" of new stars, an unexpected discovery that challenges current theories on how galaxies grow and may enhance our understanding of the Universe. Galaxies more than 1 million light-years apart should have completely independent lives in terms of when they give birth to new stars. But galaxies separated by up to 13 million light-years slowed down and then simultaneously accelerated their birth rate of stars. It appears that these galaxies are responding to a large-scale change in their environment in the same way a good economy can spur a baby boom. Regardless of whether these galaxies were next-door neighbours or not, they stopped and then started forming new stars at the same time, as if they'd all influenced each other through some extra-galactic social network. The simultaneous decrease in the stellar birth rate in the 36 dwarf galaxies began 6 billion years ago, and the increase began 3 billion years ago. Understanding how galaxies evolve requires untangling the many processes that affect them over their lifetimes (billions of years). Star formation is one of the most fundamental processes. The stellar birth rate can increase when galaxies collide or interact, and galaxies can stop making new stars if the gas (mostly hydrogen) that makes stars is lost.

Star formation histories can paint a rich record of environmental conditions as a galaxy "grew up." Dwarf galaxies are the most common but least massive type of galaxies in the Universe, and they are especially sensitive to the effects of their surrounding environment. The 36 dwarf galaxies included a diverse array of environments at distances as far as 13 million light-years from the Milky Way. The environmental change the galaxies apparently responded to must be something that distributes fuel for galaxies very far apart. That could mean encountering a huge cloud of gas, for example, or a phenomenon in the Universe we don't yet know about. The scientists used two methods to compare star formation histories. One uses light from individual stars within galaxies; the other uses the light of a whole galaxy, including a broad range of colours. The full impact of the discovery is not yet known as it remains to be seen how much our current models of galaxy growth need to be modified to understand this surprise. If the result cannot be explained within our current understanding of cosmology, that would be a huge implication

HUBBLE TRACKS DOWN FAST RADIO BURSTS
NASA/Goddard Space Flight Center

Astronomers using the Hubble Space Telescope have traced the locations of five brief, powerful radio blasts to the spiral arms of five distant galaxies. Called fast radio bursts (FRBs), these extraordinary events generate as much energy in a thousandth of a second as the Sun does in a year. Because these transient radio pulses disappear in much less than the blink of an eye, researchers have had a hard time tracking down where they come from, much less determining what kind of object or objects is causing them. Therefore, most of the time, astronomers don't know exactly where to look. Locating where these blasts are coming from, and in particular, what galaxies they originate from, is important in determining what kinds of astronomical events trigger such intense flashes of energy. The new Hubble survey of eight FRBs helps researchers narrow the list of possible FRB sources. The first FRB was discovered in archived data recorded by the Parkes radio observatory on July 24, 2001. Since then astronomers have uncovered up to 1,000 FRBs, but they have only been able to associate roughly 15 of them to particular galaxies. In the Hubble study, astronomers not only pinned all of them to host galaxies, but they also identified the kinds of locations they originated from. Hubble observed one of the FRB locations in 2017 and the other seven in 2019 and 2020. The galaxies in the Hubble study existed billions of years ago. Astronomers, therefore, are seeing the galaxies as they appeared when the universe was about half its current age. Many of them are as massive as our Milky Way. The observations were made in ultraviolet and near-infrared light with Hubble's Wide Field Camera 3. Ultraviolet light traces the glow of young stars strung along a spiral galaxy's winding arms. The researchers used the near-infrared images to calculate the galaxies' mass and find where older populations of stars reside. The images display a diversity of spiral-arm structure, from tightly wound to more diffuse, revealing how the stars are distributed along these prominent features. A galaxy's spiral arms trace the distribution of young, massive stars. However, the Hubble images reveal that the FRBs found near the spiral arms do not come from the very brightest regions, which blaze with the light from hefty stars. The images help support a picture that the FRBs likely do not originate from the youngest, most massive stars.

These clues helped the researchers rule out some of the possible triggers of types of these brilliant flares, including the explosive deaths of the youngest, most massive stars, which generate gamma-ray bursts and some types of supernovae. Another unlikely source is the merger of neutron stars, the crushed cores of stars that end their lives in supernova explosions. These mergers take billions of years to occur and are usually found far from the spiral arms of older galaxies that are no longer forming stars. The team's Hubble results, however, are consistent with the leading model that FRBs originate from young magnetar outbursts. Magnetars are a type of neutron star with powerful magnetic fields. They're called the strongest magnets in the Universe, possessing a magnetic field that is 10 trillion times more powerful than a refrigerator door magnet. Astronomers last year linked observations of an FRB spotted in our Milky Way galaxy with a region where a known magnetar resides. Owing to their strong magnetic fields, magnetars are quite unpredictable. In this case, the FRBs are thought to come from flares from a young magnetar. Massive stars go through stellar evolution and becomes neutron stars, some of which can be strongly magnetized, leading to flares and magnetic processes on their surfaces, which can emit radio light. Our study fits in with that picture and rules out either very young or very old progenitors for FRBs. The observations also helped the researchers strengthen the association of FRBs with massive, star-forming galaxies. Previous ground-based observations of some possible FRB host galaxies did not as clearly detect underlying structure, such as spiral arms, in many of them. Astronomers, therefore, could not rule out the possibility that FRBs originate from a dwarf galaxy hiding underneath a massive one. In the new Hubble study, careful image processing and analysis of the images allowed researchers to rule out underlying dwarf galaxies. Although the Hubble results are exciting, the researchers say they need more observations to develop a more definitive picture of these enigmatic flashes and better pinpoint their source.

CHARTING EXPANSION OF UNIVERSE WITH SUPERNOVAE
National Institutes of Natural Sciences

An international research team analyzed a database of more than 1000 supernova explosions and found that models for the expansion of the Universe best match the data when a new time dependent variation is introduced. If proven correct with future, higher-quality data from the Subaru Telescope and other observatories, these results could indicate still unknown physics working on the cosmic scale. Edwin Hubble's observations over 90 years ago showing the expansion of the Universe remain a cornerstone of modern astrophysics. But when you get into the details of calculating how fast the Universe was expanding at different times in its history, scientists have difficulty getting theoretical models to match observations. To solve this problem, a team of researchers analysed a catalogue of 1048 supernovae which exploded at different times in the history of the Universe. The team found that the theoretical models can be made to match the observations if one of the constants used in the equations, appropriately called the Hubble constant, is allowed to vary with time. There are several possible explanations for this apparent change in the Hubble constant. A likely but boring possibility is that observational biases exist in the data sample. To help correct for potential biases, astronomers are using Hyper Suprime-Cam on the Subaru Telescope to observe fainter supernovae over a wide area. Data from this instrument will increase the sample of observed supernovae in the early Universe and reduce the uncertainty in the data. But if the current results hold-up under further investigation, if the Hubble constant is in fact changing, that opens the question of what is driving the change. Answering that question could require a new, or at least modified, version of astrophysics.

MOST ANCIENT SPIRAL GALAXY WITH DISCOVERED
National Institutes of Natural Sciences

Analyzing data obtained with the Atacama Large Millimeter/submillimeter Array (ALMA), researchers found a galaxy with a spiral morphology by only 1.4 billion years after the Big Bang. This is the most ancient galaxy of its kind ever observed. The discovery of a galaxy with a spiral structure at such an early stage is an important clue to solving the classic questions of astronomy: "How and when did spiral galaxies form?" The Milky Way Galaxy, where we live, is a spiral galaxy. Spiral galaxies are fundamental objects in the Universe, accounting for as much as 70% of the total number of galaxies. However, other studies have shown that the proportion of spiral galaxies declines rapidly as we look back through the history of the Universe. So, when were the spiral galaxies formed? Researchers noticed a galaxy called BRI 1335-0417 in the ALMA Science Archive. The galaxy existed 12.4 billion years ago and contained a large amount of dust, which obscures the starlight. This makes it difficult to study this galaxy in detail with visible light. On the other hand, ALMA can detect radio emissions from carbon ions in the galaxy, which enables us to investigate what is going on in the galaxy. The researchers found a spiral structure extending 15,000 light-years from the centre of the galaxy. This is one third of the size of the Milky Way Galaxy. The estimated total mass of the stars and interstellar matter in BRI 1335-0417 is roughly equal to that of the Milky Way. Then the question becomes, how was this distinct spiral structure formed in only 1.4 billion years after the Big Bang?

The researchers considered multiple possible causes and suggested that it could be due to an interaction with a small galaxy. BRI 1335-0417 is actively forming stars and the researchers found that the gas in the outer part of the galaxy is gravitationally unstable, which is conducive to star formation. This situation is likely to occur when a large amount of gas is supplied from outside, possibly due to collisions with smaller galaxies. The fate of BRI 1335-0417 is also shrouded in mystery. Galaxies that contain large amounts of dust and actively produce stars in the ancient Universe are thought to be the ancestors of the giant elliptical galaxies in the present Universe. In that case, BRI 1335-0417 changes its shape from a disk galaxy to an elliptical one in the future. Or, contrary to the conventional view, the galaxy may remain a spiral galaxy for a long time. BRI 1335-0417 will play an important role in the study of galaxy shape evolution over the long history of the Universe.

METHOD TO REDUCE STRAY LIGHT ON SPACE TELESCOPES
University of Liege

A team of researchers has developed a method to identify the contributors and origins of stray light on space telescopes. This is a major advance in the field of space engineering that will help in the acquisition of even finer space images and the development of increasingly efficient space instruments. Space telescopes are becoming more and more powerful. Technological developments in recent years have made it possible, for example, to observe objects further and further into the Universe or to measure the composition of the Earth's atmosphere with ever greater precision. However, there is still one factor limiting the performance of these telescopes: stray light. A phenomenon that has been known fora long time, stray light results in light reflections (ghost reflections between lenses, scattering, etc.) that damage the quality of images and often lead to blurred images. Until now, the methods for checking and characterizing this stray light during the development phase of the telescopes have been very limited, making it possible to "just" know whether or not the instrument was sensitive to the phenomenon, forcing engineers to revise all their calculations in positive cases, leading to considerable delays in the commissioning of these advanced tools. Researchers have developed a revolutionary method for solving this problem by using a femto-second pulsed laser to send light beams to illuminate the telescope. Thanks to this, and using an ultra-fast detector (of the order of 10-9 seconds of resolution, i.e. a thousandth of a millionth of a second), the image is measured and the different stray light effects at different times. In addition to this decomposition, each of the contributors can be measured using their arrival times, which are directly related to the optical path, and thus know the origin of the problem. This method could lead to a small revolution in the field of high-performance space instruments and responds to an urgent problem that has been unresolved until now. In the near future, researchers intend to continue the development of this method, to increase its TRL (Technology Readiness Level) and bring it to an industrial level. An industrial application is already planned for the FLEX (Fluorescence Explorer) project, an Earth observation telescope that is part of ESA's Living Planet Program. The researchers hope to be able to apply it to scientific instruments as well.

Bulletin compiled by Clive Down
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