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A supernova that may shed light on how the first stars died

Space Astronomy Now

Astronomers find an apparent pair-instability supernova, a titanic blast that may shed light on how the first stars ended their lives in a metal-poor cosmos.
'An artist’s impression of a supernova – SN2016iet – going off in a dense stellar environment. Image: Gemini Observatory/NSF/AURA/ illustration by Joy Pollard Astronomers have found an apparent pair-instability supernova, the explosion of a star 200 times more massive than the Sun in a previously uncharted dwarf galaxy some one billion light years away. It is the most massive star yet found to undergo a supernova blast and may reflect how huge, metal-poor stars that formed in the immediate aftermath of the big bang ended their lives. But the devil is in the details, and the observations do not exactly match theoretical expectations. “Everything about this supernova looks different, its change in brightness with time, its spectrum, the galaxy it is located in and even where it’s located within its galaxy,” said Edo Berger, an astronomer at Harvard University and a co-author of a paper in the Astrophysical Journal . “We sometimes see supernovas that are unusual in one respect, but otherwise are normal. This one is unique in every possible way.” The supernova, catalogued as SN2016iet, was first noticed in 2016 by the European Space Agency’s Gaia satellite. Followup-up studies utilised a variety of instruments, including the CfA/Harvard & Smithsonian’s MMT observatory in Arizona and the Magellan telescopes at the Las Campanas Observatory in Chile. The progenitor star was located about 54,000 light years from the center of a previously unknown dwarf galaxy in an environment poor in heavier elements. The star lost about 85 percent of its mass over the past few million years, the researchers say. But in a surprise, they found about half of its remaining mass was lost in the final 10 years of its life. The collision between that material and the debris thrown off in the final detonation led to its unusual appearance and hints that a pair-instability supernova had taken place. Before-and-after images showing the explosion of a star some 54,000 light years from the center of a previously unknown host galaxy a billion light years from Earth. The blast apparently was triggered by quantum mechanical effects and may help astronomers better understand how the first generation of massive, metal-poor stars ended their lives. Image: Center for Astrophysics In a pair-instability supernova, massive stars generate so much energy in their cores that high-energy gamma rays can create electron-positron pairs when colliding with atomic nuclei. That reduces the radiation pressure holding the core up against the inward crush of gravity, leading to a partial collapse of the core. Runaway nuclear reactions then lead to the final collapse in a supernova blast that completely destroys the star, leaving nothing behind in its wake. “The idea of pair-instability supernovas has been around for decades,” said Berger. “But finally having the first observational example that puts a dying star in the right regime of mass, with the right behaviour, and in a metal-poor dwarf galaxy is an incredible step forward. SN2016iet represents the way in which the most massive stars in the universe, including the first stars, die.” The researchers plan to continue monitoring SN2016iet, on the lookout for additional clues about its birth and evolution. “The unexpected part is that the star lost about half its mass in the final decade before the explosion, and then the pair-instability explosion debris plowed into this lost shell of material,” Berger said in an email exchange. “None of the theoretical models of pair-instability explosions predict this behaviour. Ultimately, this is why in astronomy we rely on observational data to make new discoveries.”'

A core-warping impact in Jupiter’s past?

Space Astronomy Now

Researchers a collision between Jupiter and a still-forming planet at the dawn of the solar system best explains data suggesting the gas giant's core is less dense than expected.
'An artist’s impression of a massive still-forming planet crashing into Jupiter at the dawn of the solar system 4.5 billion years ago. Such an impact might explain puzzling gravitational readings from NASA’s Juno spacecraft. Image: K. Suda & Y. Akimoto/Mabuchi Design Office, courtesy of Astrobiology Center, Japan Puzzling data from NASA’s Juno probe, indicating Jupiter’s core is less dense and more spread out than expected, could be explained by a cataclysmic head-on collision between the gas giant and a smaller, but still massive planet at the dawn of the solar system 4.5 billion years ago. Computer simulations carried out by Shang-Fei Liu, an astronomer at Sun Yat-sen University in Zhuhai, China, convinced fellow researcher Andrea Isella of Rice University, originally a skeptic, that an impact scenario “was not so improbable.” “Because it’s dense, and it comes in with a lot of energy, the impactor would be like a bullet that goes through the atmosphere and hits the core head-on,” Isella said. “Before impact, you have a very dense core, surrounded by atmosphere. The head-on impact spreads things out, diluting the core.” Liu’s calculation showed an Earth-size proto-planet would not survive an impact and would simply disintegrate in Jupiter’s thick atmosphere. Likewise, a planet hitting Jupiter at a grazing angle likely would become gravitationally trapped and sink into the core. Computer simulations show how a planetary impact could have deformed Jupiter’s extremely dense, initially compact core. Image: Shang-Fei Liu/Sun Yat-sen University As for the odds of a head-on collision, the researchers carried out thousands of computer simulations, showing that a fast-growing Jupiter would have perturbed the orbits of nearby protoplanets, with “strong gravitational focusing” making head-on collisions more likely than grazing impacts. In all cases, Liu says, there was at least a 40 percent chance Jupiter would experience a planetary collision within its first few million years. “The only scenario that resulted in a core-density profile similar to what Juno measures today is a head-on impact with a planetary embryo about 10 times more massive than Earth,” Liu said. He added that even if the impact occurred 4.5 billion years ago, “it could still take many, many billions of years for the heavy material to settle back down into a dense core under the circumstances suggested by the paper.” The research appears in the journal Nature .'

Persistence – and adaptive optics – track Io volcanoes

Space Astronomy Now

Using adaptive optics, researchers have been monitoring Jupiter's tortured moon Io for the past five years, gaining new insights into its persistent volcanism.
'Io, as imaged by NASA’s Galileo spacecraft in 1997. The reddish ring surrounds a volcano known as Pele. Image: NASA/JPL/University of Arizona Stretched and squeezed by Jupiter’s titanic gravity as it revolves around the giant planet along a not-quite-circular orbit, the pockmarked moon Io is the most volcanically active world in the solar system. The Voyagers, Cassini and New Horizons spacecraft all monitored Io as they flew past and the Galileo spacecraft, which spent nearly eight years orbiting Jupiter, mapped the diminutive moon, allowing researchers to count more than 150 active volcanoes. Now, thanks to the adaptive optics allowing large Earth-based telescopes to counteract atmospheric turbulence, astronomers have been able to monitor thermal emissions from Io over the past five years, between August 2013 and the end of last year, including data from previous studies. The new observations were collected by the Gemini North and W.M. Keck Observatory telescopes. A sampling of Gemini North images showing hot spots near Io’s south pole. Image: de Kleer et al Over the course of 271 nights, the team, led by Caltech astronomer Katherine de Kleer, noted a total of 980 near infrared detections and 75 unique “hotspots.” The brightest eruptions, lasting just a few days, “displayed temperatures above 800 K (980 Fahrenheit), confirming that eruptions at such high temperatures are common and are likely the rule rather than the exception,” the authors write in The Astronomical Journal. Those eruptions, as noted by earlier researchers, are primarily clustered on the side of Io facing away from its direction of travel. It’s not yet known why. The current study noted 113 thermal emission detections at the extremely active Loki Patera volcano that suggests a roughly 470-day cycle that could be tied to Io’s orbital parameters. This map of hotspots detected on Io between 2013 and 2018 show how more intense eruptions tend to cluster on the hemisphere (left) facing away from the direction of travel. Image: de Kleer et al The new data set “now constitutes the largest set of unique detections of thermal emission from individual Ionian hot spots to date, permitting robust statistical analyses of properties such as the spatial distribution of hot spot activity, the variability and time-averaged power of numerous individual hot spots and the occurrence rates of bright and/or high-temperature eruptions,” the researchers write. “These data, in combination with Galileo’s sensitivity to smaller, cooler hot spots and the multidecadal time baseline provided by ground-based occultation data, are now providing a truly global, multi-wavelength picture of Io’s volcanic activity over a wide range of timescales.'

Analysis shows 1-in-6 stars may host Earth-size planets

Space Astronomy Now

A new analysis shows roughly Earth-size planets in habitable-zone orbits can likely be found around one in six relatively nearby Sun-like stars.
'As if showing a higher-resolution view of Vincent van Gogh’s “Starry Night,” a modern artist imagines the now-retired Kepler space telescope looking out over a field of planetary systems. Data from Kepler and ESA’s Gaia spacecraft helped researchers refine estimates of how common Earth-size planets may be across the galaxy. Image: NASA/Ames Research Center/W. Stenzel/D. Rutter A new statistical analysis based on archived data from NASA’s exoplanet-hunting Kepler spacecraft and ESA’s Gaia shows Earth-size planets are likely orbiting one in six Sun-like stars. The study is the most accurate estimate yet, researchers say, of the potential population of roughly Earth-size worlds in the Milky Way. “We used the final catalog of planets identified by Kepler and improved star properties from the European Space Agency’s Gaia spacecraft to build our simulations,” said Danley Hsu, a graduate student at Penn State University and the first author of a paper in The Astronomical Journal. “By comparing the results to the planets cataloged by Kepler, we characterised the rate of planets per star and how that depends on planet size and orbital distance. Our novel approach allowed the team to account for several effects that have not been included in previous studies.” Based on their simulations, Hsu and Penn State professor Eric Ford, a leader of the research team, found that, on average, one in six Sun-like stars likely host planets with masses between three quarters and 1.5 times that of Earth with orbital periods ranging from 237 to 500 days. Taking uncertainties into account, the true rate could be as high as one planet for every two stars or as low as one planet for every 33. The study could play a role in how missions and instruments are designed to study the atmospheres of relatively nearby exoplanets to search for biomarkers indicative of life. “Scientists are particularly interested in searching for biomarkers … in the atmospheres of roughly Earth-size planets that orbit in the ‘habitable-zone’ of Sun-like stars,” said Ford. “Knowing how often we should expect to find planets of a given size and orbital period is extremely helpful for optimise surveys for exoplanets and the design of upcoming space missions to maximise their chance of success.”'

Flat-Earther 'Mad' Mike Hughes prepares to launch himself to space – here's how far he's likely to get

Space The Conversation

An equation from the 1890s can help us work how high Hughes can actually reach with his homemade rocket.
'The self-declared daredevil and Flat Earther “Mad” Mike Hughes is preparing for another launch in his homemade, steam-powered rocket in the Californian desert. His final goal is to reach the edge of space, but how likely is he to succeed and see that the Earth is actually spherical? Hughes’ first rocket launch was in 2014, and since then he has taken off several times in his homemade machines – reaching an altitude of 572 metres at most. His adventures have led to a number of injuries , yet he is still determined to keep going. His latest attempt was scheduled for August 11, but was once again aborted after a fault with the rocket was discovered. He will retry on August 17 . Read more: The science of superstition – and why people believe in the unbelievable Hughes believes that the Earth is flat and that he can prove that with his rocket travels (he has been given money by the Flat Earth Society ). He is willing to go out and literally risk his life to prove what he believes. But whether he will get anywhere is a different matter. So let’s take a look at his rocket to see what potential pitfalls or successes he could have. Rocket launch basics The mathematics behind the speed a rocket launch can achieve was developed in the 1890s by a Russian schoolteacher called Konstantin Tsiolkovsky . His equation calculates a speed or velocity change based on how much of the rocket’s total mass is fuel – the more fuel you have the faster you can go – and how fast it can burn this fuel. In fact, the equation is still used to this day. Orbital flight is a combination of altitude (vertical height) and horizontal velocity. To reach an orbit around the Earth you need two things. The first is to be travelling fast enough horizontally that you reach the curvature of the Earth before gravity pulls you to the ground. You also want as little atmosphere as possible, otherwise the enormous drag force from the air will both reduce your speed and heat your object up . In the 1950s, the aerospace engineer Theodore Von Karman decided that the point where the atmosphere thins so much that normal aeronautical flight (requiring atmosphere) is impossible is at 100 kilometres up (62 miles). He dubbed this line, the edge of space, the Karman line. And to orbit at this height would require a horizontal speed of 7.8 kilometres per second, which is about 17,500 miles per hour. To reach these speeds, you have to use very specific fuels and engine shapes, relying on the combustion of solids or liquids. As the fuel is heated and turned to gas it takes up a larger volume , and as such is pushed out the back of the engine, generating thrust. The more gas you can produce at higher temperatures, the faster your rocket goes. Limitations and challenges Hughes intends to use water as the fuel itself. The problem with water is that it does not boil quickly – it has a high specific heat capacity . This means it essentially takes too much energy to turn it into steam quickly enough to be able to generate a high thrust. While we don’t know the specific dimensions for Hughes’ rocket, we can use his description of “95-100 gallons of water (360-379 litres), superheated”, “leaving the rocket at the speed of sound” and weighing “around 1,800 pounds” to calculate his potential maximum altitude using Tsiolkovsky’s rocket equation. This requires us to know initial velocity (which is 330 metres per second), initial mass (which is 816 kilograms) and a final mass as all the water and steam are gone (this is 437 kilograms). The equation then gives a speed change of 206 metres per second. This means the maximum height he can reach is just over 2 kilometres, assuming he launches straight up (this is based on basic equations of motion, ignoring air resistance). This is a very respectable height to reach on a homemade engine. But Mount Whitney , which is close to Hughes’ launch site in California, has a peak of almost 4.5 kilometres (2.8 miles). Neither altitude is anywhere close to the edge of space. It is not even high enough to see the curvature of the Earth, which requires a minimum height of about 10 kilometres (6.2 miles) . Despite this, Hughes has stated he wants funding to enable him to reach the Karman line in his next flight. Reversing our calculations, we can estimate that he would need a minimum velocity change of 1.4 kilometres per second (0.9 miles per second) to do that, and this would require his rocket to hold at least 29,000 litres of water (7,500 US gallons). This is no easy feat as it would require a fuel tank with a volume of 30 cubic metres, which is roughly the carrying capacity of two long wheel base vans . The increased size of the fuel tank and supporting structure would then increase the final weight, which in turn would require even more fuel. The engineering required to contain the internal pressure of this water and turn it instantly into steam may be very difficult. Read more: Flat Earthers vs climate change sceptics: why conspiracy theorists keep contradicting each other While Hughes’ current launch attempt may well succeed, the chances of a rocket with a 30 cubic metre fuel tank full of water taking off is close to impossible. At least he would avoid the catastrophe of the fuel exploding on the launch pad , which is a concern for more serious rocket launches. Commercial ventures such the Falcon rockets , and Blue Origin have put a lot of money into research and if they could use something as cheap as water to launch then they would do so. Ultimately, Hughes will not make it anywhere near high enough to see the curvature of the Earth, but I suspect the adrenaline rush will more than make up for it. Personally, I wish him all the best for his next flight. I may not agree with his beliefs, his politics or his distrust of science, but I do applaud his spirit and attitude. Ian Whittaker does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.'

Galaxy truffles are back and you can buy them in Tesco

Space The Scottish Sun

GALAXY has brought back its much-missed truffle chocolates to Tesco stores – and this time they have their very own box. Fans of the Galaxy favourite were devastated when the tasty treat was removed from boxes of Celebrations back in 2011. Mars, the
'GALAXY has brought back its much-missed truffle chocolates to Tesco stores – and this time they have their very own box. Fans of the Galaxy favourite were devastated when the tasty treat was removed from boxes of Celebrations back in 2011. Galaxy Galaxy Truffles are back and you can buy them in Tesco[/caption] Mars, the confectionery bosses behind brands including Galaxy and Milkyway, swapped out the truffles for Twix sweets. There hasn’t been any other major switches in the Celebrations collection since in launched in 1997. Furious by the decision, chocolate lovers even started an online petition demanding Mars reverse the decision. But now Galaxy appears to have listened to these demands and today revealed Galaxy Truffles have made a return to Tesco stores. The popular chocolatey goods are being sold now nationwide, in store and online , with no specific end date. Instagram users were delighted by the news They come in their own bespoke box and cost £5 for 206g. For those with a real sweet tooth, a bigger box weighing 329g and costing £7.49 will be available from mid-September. We’ve asked Galaxy for an exact date when these will be released, as well as calorie information and sugar content for both sizes. The Sun has also asked if the new sweets use the same recipe as the traditional ones that appeared in the Celebrations boxes and we’ll update this article when we know more. If you don’t remember what a Galaxy Truffle tastes like, each sweet has a velvety chocolate centre with a hard but sweet outside shell. News has already spread fast with confectionery lovers sharing their excitement online. Writing on the Kevs Snack Reviews Instagram page, one person said: “Things are looking up.” While another asked her friend: “Do you think them truffles will be like your faves that use to be in celebrations?!” Tesco sell a whole range of Galaxy products including the traditional bars, bags of counters and hot drinking chocolate. You can pick up a 110g bar of the stuff for just £1, while a 112g bag of counters will set you back £1.50. But be careful not to snack of both of these in their entirety as the bar contains 545 calories and 55g of sugar while the counters have 528 calories and 58g of sugar. The hot drinking chocolate costs £2.60 for a 370g tub, while 100g of this has 389 calories and 63g of sugar. The recommended daily sugar allowance for UK adults is 30g. \t \t\t \t\t \t\t \t\t\t \t\t\t\t \t\t\t\t\t \t\t\t\t\t\t\t\t\t\t\t MORE ON MONEY \t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t \t\t\t\t\t\t\t\t\t\t \t\t\t\t\t \t\t\t\t\t\t \t\t\t\t\t \t\t\t \t\t\t\t \t\t\t\t \t\t\t \t\t\t\t\t \t\t \t\t\t\t\t \t\t\t\tHOUSE ABOUT THAT\t\t\t \t\t\t\t\t\t\t \t\t\t\tFirst-time buyers guide to getting a mortgage and help from the government\t\t\t \t\t\t \t \t \t \t\t\t\t\t \t\t\t \t\t\t\t \t\t\t\t \t\t\t \t\t\t\t\t \t\t \t\t\t\t\t \t\t\t\tDRIVE DOWN COSTS\t\t\t \t\t\t\t\t\t\t \t\t\t\tHuge rise in extra charges from car insurers adds £140 a year to bills\t\t\t \t\t\t \t \t \t \t\t\t\t\t \t\t\t \t\t\t\t \t\t\t\t \t\t\t \t\t\t\t\t \t\t \t\t\t\t\t \t\t\t\tMONEY MATTERS\t\t\t \t\t\t\t\t\t\t \t\t\t\tGrandparents must claim pension credit before deadline or lose up to £70k\t\t\t \t\t\t \t \t \t \t\t\t\t\t \t\t\t \t\t\t\t \t\t\t\t \t\t\t \t\t\t\t\t \t\t \t\t\t\t\t \t\t\t\tFLIGHT FIGHT\t\t\t \t\t\t\t\t\t\t \t\t\t\tHow can I claim compensation if my flight is delayed or cancelled?\t\t\t \t\t\t \t \t \t \t\t\t\t\t \t\t\t \t\t\t\t \t\t\t\t \t\t\t \t\t\t\t\t \t\t \t\t\t\t\t \t\t\t\tDANCE OFF\t\t\t \t\t\t\t\t\t\t \t\t\t\tWhy has Houghton Festival been cancelled and how can I get a refund on tickets?\t\t\t \t\t\t \t \t \t \t\t\t\t\t \t\t\t \t\t\t\t \t\t\t\t \t\t\t \t\t\t\t\t \t\t \t\t\t\t\t \t\t\t\tTICKED OFF\t\t\t \t\t\t\t\t\t\t \t\t\t\tBoardmasters festival cancelled - can you get a refund of your ticket or travel?\t\t\t \t\t\t \t \t \t \t\t\t\t\t \t\t\t\t\t \t\t\t\t\t \t\t\t\t \t\t\t \t\t \t \t \t \t In more good news for chocolate lovers, Cadbury recently announced a new range of white chocolate products including buttons and Freddo Treasures. While Snickers has released a new “crisp” chocolate bar with puffed rice, caramel and peanuts. Shoppers can also try out new salted caramel M&Ms. \t\t \t\t\t\t\t \t\t\t\t \t\t\t\t\t\t\t\t\t\t \t\t\t\t\t\t\t\t\t \t\t\t \t\t\t\t \t\t We pay for your stories! Do you have a story for The Sun Online Money team? Email us at money@the-sun.co.uk'