Galactic Black Hole Eruptions, Snowball Earth Theories, and the Impact of SkyMapper

This is Spacetime Series twenty nine, Episode fifty nine, for broadcast on the eighteenth of May twenty twenty six. Coming up on Spacetime, A black hole flare explodes in the heart of our galaxy. Trying to explain one of the mysteries of snowball Earth and the legacy of Australia's Skymappers survey. So far, All that and more coming up on space Time. Welcome to space Time with Stuart Gary. Astronomers have observed a dramatic mid in for red flair erupting from Sagittarius, a star, supermassive black hole at the center of our galaxy. The discovery, reported on the pre press physics website archive dot org, follows twenty years of searching for just such an event. Sagittarius a star is located some twenty seven thousand light years away at the very heart of the galaxy, and it has some four point three million times the mass of our Sun. This new detection was made by the WEB Space telescope, which is exquisitely sensitive to admit infrared events. Web's observations show that the blast lasted some forty minutes, and its implications could fundamentally transform sciences understanding of black hole behavior and the violent magnetic environments just outside their event horizons. The event horizon is the point of no return around the black hole, beyond which matter falls forever into the black hole's singularity, a point of infinite density and zero volume, where science is understanding of the laws of physics, space and time break down. While Sagittarius a star has been seen flaring before, recorded in radio waves, near infrared and X ray frequencies, the mid infrared window has remained stubbornly dark until now, and so this new observation finally completes a long sort after supermassive black hole's multi wavelength portrait, astronomers think the flare was triggered by something called magnetic reconnection. This involves intensely tangled magnetic food lines near the black hole suddenly realigning, snapping, and then reconnecting, unleashing a massive pulse of energy in the process, and that energy accelerated electrons to relativistic speeds, which then emitted synotron radiation as they whipped around the reconfigured magnetic fields. This new observation has allowed astronomers to see the event unfold in real time, revealing the unmistakable spectral fingerprint of synotron radiation cooling as the high energy electrons bled away energy through radiation. These new observations will allow astronomers to better directly probe and measure the black hole's magnetic field strength near the event horizon with unprecedented detail, to develop a better understanding of how super massive black olds devour matter, ignite sudden outbursts, and exert their gravitational and magnetic dominance over entire galaxies. This is space time still to come, a new explanation for some of the unsolved riddles about snowball Earth, and we look at the legacy so far of Australia's SkyMapper project. All that and more still to come on space time. Scientists have developed a new explanation for one of Earth's great climatic puzzles, how a snowball Earth event known as the Sturdy and Glaciation could have lasted as long as it did. The research publishing the Proceedings in the National Academy of Sciences suggests that, rather than a single fifty seven million year long unbroken snowball Earth state, Sturdy Glaciation may have seen the planet oscillate between fully ice covered conditions and more ice free states. As the name suggests, snowball Earth events occur when our planet is almost completely covered in snow and ice. The exact reasons for this are still under active debate, although plate tectomics and changes in Earth's orbit and axial tilt are thought to have played at least a part in these dramatic climatic change events. Scientists generally agree on two major snowball Earth periods. These were the Sturdy Glaciation, which went from around seven hundred and seventeen to six hundred and sixty million years ago, and the Marino Glaciation from around six hundred and fifty to six hundred and thirty five million years ago. Some scientists suggest there may will have been a third earlier glaciation event, known as the mcganny Glaciation, which occurred at around two point two billion years ago. However, the exact length and intensity of all these events remains uncertain, and the fifty six million YU duration of the Sturdy Glaciation during Earth's Crogian period is especially problematic as it challenges some climate models. The studies lead author Charlotte Minsky from Harvard University says this was a time which predates the age of the dinosaurs in most complex lifeforms. Minsky and colleagues used a coupled model of the ancient climate and the global carbon cycle to show that the Earth may not have been locked in a single unbroken snowboll earth state or period when the entire planet was frozen over. Instead, they proposed a planet likely oscillated between fully ice covered snowball conditions and more ice free hothouse intervals throughout the sturdy In period. The author's simulation suggest that intense weathering of basalt in the Franklent large igneous province, a vast volcanic region located in northern Canada, leave to have erupted just before the onset of the Sturdy glaciation, may have drawn down atmospheric cab dioxide, a greenhouse gam and it removed enough of it from the atmosphere to trigger modible global glaciations. As volcanoes and other processes slowly rebuilt atmospheric carb dioxide, the climate warmed again and the ice retreated, and large areas of fresh basalt were again exposed to the atmosphere. The renewed breakdown from weathering then pulled cob dioxide back down, pushing the climate into another snowball phase. The authors argued that this repeating cycle of calm dioxide driven freezing and thawing could naturally sustain glacial interglacial swings over tens of millions of years. The mechanisms revealed by this study resolved several long standing paradoxes, most noticeably the previously inexplicable length of the Sturtian compared with physical climate models. The study also matches observed sedimentary patterns from that time period and it explains how atmospheric oxygen levels could have remained stable despite extreme climate up evils. The study seeings that repeated returns to warmer, ice free conditions may have helped prevent a complete collapse of atmospheric oxygen, and Minski says this could explain how aerobic life persisted through such an extreme period. This is space time still to come. We look back at the legacy so far of Australia's sky Mapper Southern Survey, and later in the science report, paleontologists discover fossils of a new type of plant eating dinosaur in Thailand all that and more still to come on space time. It was almost exactly ten years ago that the Australian National University sky Mapper telescope released an initial eighteen terabytes of observations of the Southern Skies. Was the first of more than two petabytes of raw and calibrated information that has helped change forever sciences understanding of the cosmos and our play in it. By the time of its fourth and most recent data release, SkyMapper Southern Survey covered more than half the sky, generating some four hundred thousand images showing seven hundred million objects and achieving fifteen billion detections. SkyMapper is a wide field survey telescope located at the Siting Spring Observatory in far western New South Wales. Observatory is director Christian Wolf, says skymappers unprecedented images and measurements are creating the first comprehensive digital survey of the entire Southern Sky. He says the end result will be a massively detailed record of more than a billion stars and galaxies, all to a sensitivity of a million times fainter than what the human eye can see. Yes, we've been looking for quasars, especially e quasars at high redshift in the early Universe quite a while. Now. Sky Mapper is a bit late to that game, because a lot of quasars in the Early Universe have been found by the Sloan Digital Sky Survey or the Northern Sky and SkyMapper is in the first survey that really goes to similar depths studying the Southern skies. But really what we want to do is push the envelope and really get good demographics of the fastest growing and most massive black holes in the universe. What we also can do is quasars are supposed to be a really really large distances, and especially when we believe they are in the early Universe, then they're not supposed to move at all, as opposed to the foreground stars of our own Milky Way. And so we were able to read out our candidate list, which are we're trying to look for these high retive quasars, and then because their colors are similar to cool stars in our own galaxies, our lists of possible high chif us are polluted with vast amounts of Milky Way stars that we're not really interested in. And when we want to know what a particular object is. We have to point a spectrograph at it, at a somewhat bigger telescope, and then we have to check them off one by one. So what is this exactly? If this is a start out, take the spectrum, a stuff, this one over here is that, let's take a spectrum, another star, and so on, and you can't afford to go through all of them because there would be millions of candidates. So really, Gaya has helped us to weed out a lot of this contamination by a milky ways four ground stars. It doesn't completely remove that we still find stars among our candidates, but at least it's now being realistic to find these very rare and very fast growing, very bright kays as. Our work right here with the skymert the telescope focused on getting the big guys, the monsters, and we believe that they have been largely overlooked. In fact, anytime someone has discovered the now brightest or now fastest growing black holes, they've been saying, wait a minute, we've had this on our candidate lists forever. We thought this was a star. We were pretty sure this was a star. We didn't you look at it in detail? Because it was so unlikely to actually be a quasus. When you look at very faint objects, you get a number of quadars among the stars. But as you go to brighter and brighter ones, quasars become rapidly raarer, up to the point where you think, well, we haven't seen anyone brighter than this one, so you know they are probably pretty rare. So everything you then see at that brightness you think must be a star anyway, So we have this kind of biased few that the brightest ones are most likely stars, so we don't go after them because we don't enjoy taking spectra of a thousand stars only to learn that there wasn't a single black hole or quasa among them. That we probably don't even get the time telescopes avoid for that, just because it's such an such an unlikely to be successful undertaking. And this is why we have missed the monsters. There are monsters out there, and but that's what we are setting out to correct now. So by combining Gaya that we thow a lot of the candidates from the candid list with Taypa. That can take still so many spectra of objects, most of which are not going to equas us, we can actually afford to attempt to get the complete demographics of bright praisers in the early universe and therefore map out the growth of black holes with time in the early epochs. With these sky data online and being available for everyone to see, that's got to be a tremendous boost for astronomy generally. I think it's what developing something like two petabytes of data starting the southern sky thirty six times six hundred thousand images something like that. Yes, that's the right order of magnitude indeed, And fortunately the sky Mapper project was intended to start up ten years earlier, but the first prototype of the Skyper system, that was actually at Mount Stromlow just outside of Canberra, was burned down in the early bushfires of January two thousand and three. Then it took a while to build a brand new sky Mapper, which then was of course put at siding Spring Observatory, which also almost precisely on the tenth anniversary of the Stromlow bushfires. The siding Spring bushfires happened and Skymper was about ready to start its survey and was inundated in ash and it took four months of meaning of the optic mechanics and everything to get it back to where we wanted it, and we actually did lose some kit in the process, some little kit, but anyway, so in some ways we are fortunate because the capacity of computers and discs and so on has improved a great deal over time, so now we can actually do it for a reasonable cost. We offer our data online over the Internet. Everyone can access it, scientists, teachers, the interested public who just wants to have a look. Guymapper has several color filters, six of them that cover the the color range from the near ultra violet, which the human eye just about cannot see anymore, through the visual that the I sees very well too, equipments in the near infrared that again the eye just about can't see anymore. And stars show usually typical color patterns, but the exact pattern depends on how many absorption lines are in the spectrum, and most stars in Milky Way have quite a lot of these absorption lines and have really areas where the absorption lines are heavily affecting the colors. And when you get something like a nearly perfect rainbow, then you know, oh we have a metal poor star. That's what we call it a star with few heavy elements, a star with few absorption lines. And so we're selecting these stars baits on their color. And then again we need to go to a bigger telescope and take some more refined measurements, measure the spectrum indeed, and see what we've got. How metal poor is it, how chemically pristine. On the one hand, we really look for thousands of these metal poor stars which are from the first generation of stars formed in our Milky Way galaxy around about thirteen billion years ago. These will be population two stars. Yeah, these are population two stars. And these are actually extreme population two stars, not just average population. The ones that actually were formed from those population threes. That's right, that's right. I mean, the term population two stars still covers a couple billion years of time in the formation history of the Milky Way, and we are essentially pushing towards the early limits of that period, and we aim to find several thousand of these very metal poor population two stars to learn what the Milky Way really looked like at these early ages, and then of course finding the most chemically pristine one. Going after the record here and seeing what's possible out there what has still survived until today. That's of course a big part of it. And maybe one day we find an even even more pristine one than this one that was found in twenty fourteen. That's doctor Christian Wolf, the director of the Siling Spring Observatory. And this is space time and time that to take a brief look at some of the other stories making news and science this week with a science report. A new study warns that obesity trends are now rising faster in low and middle income countries, but at the same time they've started to level off in many high income nations. The findings, reported in the journal Nature, looked at data from two hundred and thirty two million people across two hundred countries and territories over the past forty five years. The authors found that obesity rates increased over the study period, but trends have varied in different populations. For high income countries like Australia and the United States, the rates went up at the start of the measuring period, but have since plataued. In comparison, the rise in obesity rates in lower middle income countries has risen sharply, now encompassing some thirty to forty percent of all adults. A new study warns that a key Atlantic ocean current system that helps regulate the planet's climate could weaken more than expected by the year twenty one hundred. The findings, reported in the journal Science Advances, claims the collapse of the Atlantic meridiurnal overturning circulation, which powers things like the Golf Stream, would have devastating consequences worldwide. This conveyor build of currents plays a crucial role in redistributing heat by transporting warmer waters from the tropics northward. The weakening of the Golf Stream would cause harsher winters in Northern Europe, droughts in South Asia and the Shahill region of Africa, and highest sea levels in North America. Previous climate model predictions estimated an average slowdown of around thirty two percent the end of the century due to climate change, but the new research estimates that the system could slow by as much as fifty one percent by the year twenty one hundred, and a mid range scenario for greenhouse gas emissions with the margin of error of plus or minus eight percent each points. Paleontologists have uncovered a new type of plan eating dinosaur, the largest ever found in Southeast Asia. The discovery, published in the journal Scientific Reports, was made at a dig site at the edge of a pond in northeastern Thailand ten years ago. The fossils were found in strata dating back to the Early Cretaceous period between one hundred and one hundred and twenty million years ago. The new cerropod dinosaur, named the guardian Chia neumensis, is based on analysis of spine, rib, pelvic and leg bones, including one front leg bone one point seven eight meters long that's as tall as a human. Seropods are those dinosaurs with elphint like bodies and feet, long neck and small head at one end, and a long tail of the sort of like Fred Flinstone's Patino. The authors believe this new serapod species would have weighed around twenty seven tons as an adult, that's about the same as nine elephants, and it would have measured some twenty seven meters long. Professor Steve Novella from Yale University, president of the New England Skeptical Society and a fellow of the Committee for Skeptical Inquiry, has written a paper looking at the broader problem of pseudo archaeology and those everything you've been told about history is a complete like conspiracy theories, which spread like wildfire through social media. The Skeptics timendum says. Novella points out that engaging on social media to discuss youos science can be exhausting, and that you need to keep reminding yourself that what you're seeing isn't necessarily representative. But it's only the loudest and most extreme voices that tend to get amplified. Pseudo science pseudo archaeology where people sort of claim obviously the things like bondanikers who claim that you had to get help to build all these ancient civilizations, that the people were obviously not good enough but not clever enough to build these, so we begin extra terrestrials to do it for us, or they recreate a only history and the Sony civilization one of them is particularly looking at the ancient civilization of Tartaria or Tartaria, which is sort of doesn't exist a sup of things. The Indian car isn't. It's secondly the word for Tartus from the Mongols when invaded into inter Europe. This is one example of people who are saying, look at all these buildings here, these people couldn't have built them. Interesting thing. They're talking about seventeen sixty eighteen centi of buildings, but have a lot of records of these buildings being built not by ancient civilizations, but both Stonemasons and people like that is very much in the time. The trouble is a lot of the pseudo archeology is heavily racist, based that third world countries Africans, Egyptians, Central Americans, whatever, could not have done this because they're basically inferior people and they needed aliens to flash white people to do it for them. Now we all know aliens are either green or gray. I'm not saying about the aliens being white and talking about the people who build the civilization supposedly, and there. Is a lot of that in there. There a lot of sort of end of the world, new world order. It is quite openly racist. Some of it about that we built them. You couldn't build them because he not very good enough. There's all sorts of examples of this. We've had articles in skeptic magazines about the history of pseudo archaeology. It was particularly strong in the eighteen hundreds in America. Of course, there are a lot of people who claiming that finding the Golden City, et cetera, rewriting history. Von Danikin. More recently Eric Wondanikin, who wrote The Chariots of the God stuff, which is not original at the time, but he made a lot of money out of it, rewriting history, rerunning the same way that he's saying, you couldn't have done this to euro slowly third world country civilization of the Names or the Egyptians, et cetera. That you had to have help, and Fantanica was saying as aliens others might say, it's a special civilization from Tartaria, and it's an annoying thing. It's an anti science thing. Sleeve obviously said it as indicative of a stronger anti science philosophy. Pseudo Archaeology is just one example of where it's applied. It's the problem. It's a problem. And in the world of social media set these pseudo scientific claims can spread quickly rather than by a paperback book or something like that, and it becomes an important issue from a science point of view. And he stresses at the end of his article, scholars and scientists need to engage with the world much more than they currently do. We cannot simply ignore the nonsense with the idea that it will shrivel and die if we don't give it light. That is such a pre social media idea. If it were ever true, we have to fight for scholarship or logic, facts and evidence. We have to fight for history. I fairly endorse that absolutely one hundred percent. And well, we're saying it in today's world, aren't we. It is a sad thing that we're seeing this, especially now. It's always the case, don't criticize pseudoscience things because it only gives them air. What he got the air, they don't have to trouble fighting air. No, you have to criticize them. You have to come out and be open about it. It won't just shrivel and die if they'll do the opposite. So therefore, whether it's ancient history, archaeology, pseudo archaeology, pseudo medicine, through those science generally anti science, you've got to speak up. That's the skeptics timendum and this space Time, and that's the show for now. Spacetime is available every Monday, Wednesday and Friday through at bytes dot com, SoundCloud, YouTube, your favorite podcast download provider and from space Time with Stuart Gary dot com. Space Time's also broadcast through the National Science Foundation, on Science Own Radio and on both iHeartRadio and tune in Radio. And you can help to support our show by visiting the Spacetime Store for a range of promotional merchandising goodies, or by becoming a Spacetime Patron, which gives you access to triple episode commercial free versions of the show, as well as lots of bonnus audio content which doesn't go to weir, access to our exclusive Facebook group, and other rewards. Just go to space Time with Stewart Gary dot com for full details. 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