Stellar Migration and Cosmic Dust: Unveiling Galactic Origins

This is Spacetime Series twenty nine, Episode thirty three, for broadcasts on the eighteenth of March twenty twenty six. Coming up on Space Time, What the Birth of our Sun tells us about the evolution of our galaxy, making cosmic dust in the lab, and China looking at a landing site for its first man mission to the Moon. All that and more coming up on Spacetime. Welcome to space Time with Stuart Gary. Astronomers studying the birth and early evolution of the Sun have uncovered how the shape of our galaxy has changed dramatically over the past few billion years. Our Milky Way galaxy is a bad spiral. It contained spectacular sweeping arms of stars and clouds of gas and dust, which is seen in traditional grand spiral galaxies. But there's also this thick bar of stars and gas across the galactic center. The origins of these so called stellar bars are still being debated. Stars are born in stellar nurseries deep inside molecular gas and dust clouds, often containing hundreds to thousands of protostars of varying masses varying stages of evolution. It's thought a nearby exploding star called supernova set shock waves out through the local cosmos has that exploded, causing one of these molecular gas and dust clouds to start to collapse under its own gravity, in the process triggering starbirth, including that of our own local star, the Sun. Eventually, gravitational perturbations, shock waves from other supernovae, jets of energy and mass shooting out from black holes, and or powerful stellar winds from adjacent stars cause the stars in this nursery, including our Sun, to migrate out of their stellar nurseries and take up their positions in the galaxy orbiting around the galactic center, which contains a super massive black hole known as Sagittarius, a star, our Sun, and its solar system, including the Earth, orbits around this black hole some twenty seven thousand light years from the galactic center, but astronomers believe it originally formed just seventeen thousand light years from the center. Now, a team of astronomers of uncovered evidence that the Sun migrated from its stellar nursery together with a multitude of siblings. The findings were reported in the journal Astronomy in Astrophysics for the creation of a massive catalog of stars and their properties based on data from the European space Agencies guy A satellite. The discovery sheds light on the evolution of our galaxy, including the development of the rotating stellar bar like structure at its center. Scientists know our Sun was born around four point six billion years ago, more than ten thousand light years, closer to the galactic center than where it is today. All studies of the composition of stars support this theory. This has long provided a conundrum for astronomers see Observations reveal that the enormous bar like structure and agalactic center creates a sort of co rotational barrier, which makes it difficult for stars to escape so far from the center, and that begs the question how do we get here? To answer this discu Tanagucci from Tokyo Metropolitan University and Takuji Chuzimoto from the National Astronomical Observatory of Japan carried out an unprecedentedly large study of stars which have similar temperatures surface gravity in composition to that of our Sun. They use data from. Gaya's Treasure Travel of observations covering some two billion stars and other objects both in our galaxy and beyond, to create a catalog of six five hundred and ninety four so called stellar twins stars similar to our Sun. Now that's some thirty times bigger than any previous survey of its kind. From this, they were able to obtain the most accurate picture yet the ages of these stars, carefully correcting for selection bias of stars which are easier to see. Looking at the distribution of ages, the authors noticed a broad peak of stars around forty six billion years old that includes our Sun and his evidence for similar stars, all of similar age, positioned around the same distance from the galactic center. This means our Sun isn't in its current position by accident, but part of a much larger stellar migration. Now, the discovery sheds light not only on the nature of our solar system, but the evolution of the galaxy itself. The cor rotation. Barrier created by the stellar bar structure of the galactic center wouldn't allow for such a mass event. However, the story changes if that stellar bar was still being formed at the time. The ages of our stellar twins will not only when the mass migration occurred, but also the time range over which the stellar bar itself was formed. The city of the galaxy is a far less hospitable environment for the evolution of life compared to the outer regions. So it's rather fortuitous for us that our sun so many other stars did migrate out or words. The author's findings therefore illustrate a key factor in how our solar system, and in turn, our planet found itself in the origin of the galaxy, where life was able to develop and evolve this space time still to come. How to make cosmic dust in the laboratory and china SELECXI landing site for what will be Beijing's first man mission to the Moon, or that and more still to come on space time. A new study examining how the building blocks of life are formed in extreme deep space environments has created cosmic dust in the laboratory. The findings, reported in the Astrophysical Journal, used a simple mix of gases the nytrogen, carbon dioxide and acetylene to mimic the harsh and dynamic environments around stars and supernova remnants the Steadies. Lead author Linda Leserto from the University of Sydney says the results of shedding new light on how the chemical building blocks of life may have formed long before the Earth existed. By subjecting these gases to intense electrical energy, asserta generated carbon rich cosmic dust, similar to the material found drifting between stars and embedded in comets, asteroids, and meteors. The dust she created contains a complex cocktail of carbon, hydrogen, oxygen, and nitrogen electively known as chon molecules, which are central to many organic substances essential for life. Cosmic dust is known to form in extreme astrophysical environments where molecules are constantly being bombarded by ions and electrons. Scientists can identify this dust in space because it emits a distinctive infrared signature, a molecular fingerprint that reveals its chemical structure. The dust produced in les Soto's experiments showed the same telltale Inford signatures, confirming the laboratory process closely mirrored what happens in space. Soto says the research means scientists no longer have to wait for an asteroid or comet to come to Earth in order to understand their histories. Instead, you could build analog environments in the laboratory and reverse engineer their structure using their infrared fingerprints. This gives scientists and insight to how carbonaceous cosmic dust forming the plasma puffed out by a dying red giant star, or in cosmic nurseries when neu stars are being born. One of the enduring questions in science is how life began on Earth. Scientists are still debating whether the earliest organic molecules formed locally on Earth, whether they arrived later on comets and meteors, whether they were delivered during the earliest stages of the Solar System's formation, or whether it was some combination of all free Between three and a half and four point five six billion years ago on Earth was bombarded by meteors, micro meteorites, and planetary dust particles originally from asteroids and comets, and these objects are thought to have delivered vast amounts of organic material to the Earth's surface, yet the origins of that material remains mysterious. The Soto says, covalently bonded carbon and hydrogen in commets and asteroid material are believed to have formed in the outer envelopes of stars, in high energy events like supernovae, and in interstellar environments. Now, she's trying to understand the specific chemical pathways and conditions which incorporate all of the chant elements into the complex organic structures seen in cosmic dust and meteorites. The Pudo and. Colleagues used a vacuum pump to evacuate air from glass tubes, recreating the near empty conditions of space. Nitrogen, carbon dioxide, and asceedley were then introduced. Now. The gas mixture was then exposed to around ten thousand volts of electrical potential for about an hour, thereby creating a type of plasma known as the glow discharge. Under this intense energy, molecules broke apart and then recombined into new, more complex structures, and these compounds eventually settled into a thin layer of dust on silicon chips placed inside the tubes. So says the collected dust looks like glittering collections of cosmic material. The work will allow scientists the proper conditions that are otherwise impossible to study directly. By making cosmic dust in the lab, scientists can explore the intensity of iron impacts and temperatures involved when dust forms in space, and that's important for understanding the environments found inside cosmic dust clouds, where life relevant chemistry is thought to be happening. It also helps the authors interpret what a meteoride or asteroid fragment has been going through over time. That's because its chemical signature holds a record of its journey, and experiments like this help scientists learn how to read that record. Beyond insights in the origins of life. The authors hope to build a comprehensive database of infrared fingerprints from lab made cosmic dust. Astronomers can then use this library to identify promising regions a space it's stillar nurseries or ren that's the dead stars, and work backwards to understand the process is shaping them. The sitters is that by recreating cosmic chemistry on Earth, the work opens a new window into deep stellar processes and the ancient steps that may have helped make life on Earth possible. My supervisor, Professor David McKenzie, he spent most of his career researching interesting forms of carbon. He actually discovered a type of carbon called tetrahedral amorphous carbon, which is quite a mouthful. Then I met him and started my PhD with him, and we started making these materials which were like amorphous carbons. When I say amorphous, I just mean no long range order in the structure. And then we decided we'd include some oxygen and nitrogen in as well. The reason being we started to see that more and more people were finding amorphous carbon, this particular type of carbon in space in the literature, and then we read more about it and we realize that, really, if you've got these gases that have carbon, nitrogen, oxygen hydrogen in them, that are around the envelopes of these giant dying stars, then there's no reason why you really shouldn't have oxygen and nitrogen reacting as well. And so that's when we decided we'd use this mixture and we'd make our own cosmic dust analog. And you started with a fairly simple mixture of gast. Yeah, it sounds quite simple in practice. So it's three gases, it's carbon dioxide, acetylene, and nitrogen. But what a lot of people may not realize is that when you're dealing with plasma reactions, and when I say plasma, I mean ionized gases, you're having lots of fragmentation of molecules and then lots of different reactions occurring, so plasmas themselves aren't very selective. What that means is that any types of products that you can make at an energy range, you probably will make so the moment you add a third gas, for example, so most experiments use one or two. The moment you have a third gas, you increase the complexity quite a bit. But what we were considering in our experiments is the fact that even if you have quite a complex gas mixture, so long as you know the parameters you begin with, you're able to look at how a certain parameter, be it temperature, be it pressure, affects the product in its chemical fingerprint, in its infrared spectrum. If you know the conditions you start with in the lab, and you know what the output looks like in the lab, then when you get a new sample from space, just by looking at the trends, okay, you know with temperature I get an increase in this certain species in a certain peak this type of bond. Then you can kind of that calculate and say, well, if I have a dust particle that has this chemical signature, it must have experienced these formative conditions in its lifetime. You created chung molecules. What are they? Chong is carbon, hydrogen, oxygen, nitrogen. We use the term quite loosely. They're not quite molecules. They're actually a network structure, so it's a morphous carbon backbone. Again, amorphous just means no long range order in the structure, and it's got oxygen and nitrogen and hydrogen attached, so it's a very chaotic mixture. It does quite closely resemble the insoluble organic mass found in metiorites, and that is largely why we're interested in it as well, because trying to find natural processes that make these mixtures that are found in mediaites it is quite difficult, and it's nice to have a way to replicate an indicative process and how that mediaite, how that the subcomponents of meteorites may form. Over the last few decades, there have been more and more examples found of amino acids floating out there in space. We think they're quite common. Now, is that something you'd like to recreate or is that something you have recreated? Or are you willing to sort of just let the Miller Uri experiment cover all that. Yes, So from the Millery and Ur experiments and also some experiments by Carl Sagan have really inspired me growing up, but now inspiring my work as well. I will stress at our experiments, so they are a little bit different. So what Miller and Uri did, and they are a bit different to amino acid experiment when we're looking at building blocks of life and how organic material got to Earth. Yes, it's true that a lot of it may have been these well preserved amino acids from space, but we actually know from specific types of media rites that falls called a carbonaceous chondrite, that most of the organic matter in media rite is in this insoluble organic form, and so trying to recreate that insoluble form is really what we're after here. Cabinaceous chondrites there some of the oldest substances we've ever found. What's it like to handle. Something like that, Yeah, it's it's been quite spectacular. In particular talking to media Riticist, I went to the media ritical conference this here, which was actually held in Perth, and I learned so much from people who are studying the real thing that it did. Really it inspired me for my work trying to make analogues. And I think something that I always think about is that natural processes, things that occur in these really extreme conditions in space. They've been happening for millions of years, and they are so very complex and they are so remarkable in many circumstances, the fact that you have this range of environments that occur in space, and so I often feel like you know, no matter how many different doest samples I make, maybe one might be a little bit similar to something, but I can never reach that full complexity. And I think that challenge and that knowing that the universe is so grand and so good at making these dusts is a nice little thing to think about, the fact that the more we know about the universes, even more we really we don't know, and we won't be able to replicate, or maybe it'll take a lot longer to replicate. They'll always be something to know. I completely geeked out when I got to have a close look at a Murchison media write fragment so I can understand what Firth would have been. Like for you. Do you think we'll ever reach a stage where what we now see as a chemical interaction we witness it becoming a biological interaction. I'll all answer that question as best I can. I think it's important to consider where expertise lives. I'm someone with a physics and a chemistry background, and I can do the reactions that I know about and I can understand that science, but I think in order to get from something that is abiotic, not lifelike at all, to something that is biotic will require a huge team of scientists with coming from all sorts of different backgrounds. When you start looking into how amino acids then form larger structures like DNA and protein, you realize the degree of biological complexity that is required, and there are still so so many unknowns with that. I think what is nice about science, and about this type of interdisciplinary science, is that every research group working on these types of problems makes a small step, and then when you look back at it, we've actually learned quite a lot in the last ten twenty thirty years that we didn't know before. And it's really that cumulative knowledge I think that will lead to breakthroughs. Standing on the shoulders of giants. Yeah, absolutely. I love every time I open Google scholar where we get our literature from that we read before we write papers, seeing that quote standing on the shoulder of the giants. I do think about that a lot. You know, other people have studying dust, other people have made different types of analogues of dust, and I think it's so important that myself as a researcher and my supervisor. We have so much respect the scientists have gone before us, and we hope that maybe the dust we've made inspires someone to try out their own experiment in a different way. I think that's what science is all about. It's not about holding it for yourself. It's about trying to encourage everyone to have a look and have a go. One of the big problems we have when we go to Mars, or go to Europa, or go to Enceladus, any of these places even tighten I guess, any of these places where we think life may have been in a situation where the environment was habitable enough for it to exist. We always wonder, is that really can we tell what life is? We went to Mars, we did a super experiment, and people are still scratching their heads over it. Yeah. I think that there's a really beautiful thing about how complex life is. People's definitions of it are also very different, and that's something to be very mindful of. What life means to one person may not be what it means to someone else. A lot of people will define it at an Amino Lusset level, but a lot of people say well, no, you need to wait until you have larger structures like RNA and DNA and protein before you really call that life. And I think that there's a whole philosophy aspect of this as well, in a religious aspect that scientists, you know, we can try our best to answer, but at this stage there are so so many unknowns, and it's really important to be respectful of how many different opinions there are to these types of topics. That's Linda Lesserto from the University of Sydney and this is space time still to come. China selects a landing site for its first man mission of the Moon later in the science report, and you study has shown that taking a daily multi vitamin could help you slow by life magical aging. All that and more still to come on space time. Beijing's identified four possible landing sites or will be China's first man mission to the lunar surface. Scientists used orbital images to study of the Moon's equatorial remy Boade region. A report in the journal Nature Astronomy says a man mission to the lunar surface was a high priority for Beijing and likely to happen around twenty thirty. The areas being looked at as scientifically valuable because they include varied terrains and materials which span long periods of lunar history, and that's important for understanding how the surface and interior of the Moon have changed over time. Of special interest is a dark layer of volcanic debris, a bess up playing called sinus astem to deparate valleys formed by volcanic and tectonic activities and the surrounding highlands this space time and time that to take another brief look at some of the other stories making news in science this week with the Science Report, A new study has shown that flu jabs in the United States this season have been shown to be less effective against a fast moving strain now spreading in Australia. A report in the Journal of the American Medical Association warns that influenza a H three and two subclaude K J two four one, known as super K, is spreading faster and earlier in Australia than during typical flu seasons. It was also dominant across the United States during its winter months. Scientists assists the antibody responses of forty six people received flu jabs in late twenty twenty five against a series of strains, including super K. They say the sample showed a weaker antibody response to super K compared to the other strains. It also appears that super K can partially invade immunity from prior infection with similar flu strains. The authors say there is still a modest response to super K, so while flu shots are less effective than normal, they're still likely to offer at least some protection. A new study is shown that taking a multi vitamin pill every day could help slow biological aging. The findings reported in the journal Nature, based on a study of around one thousand adults aged around seventy The authors found that in older adults, two measures of biological aging were slowed in a small but meaningful way after two years of daily multivitamin use, with greater benefits for those who began the trial with already accelerated biological aging. A major new study is shown that social media and video games are linked to poorer developmental outcomes in kidson teens. The findings were reported in the Journal of the American Medical Association show digital media use had modest but consistent links with poorer mental and physical health outcomes. To reach their conclusions, the authors pulled data from one hundred and fifty three previous studies. They found that social media was linked to a range of worse outcomes, including depression, problematic internet use, substance abuse, and lower academic achievement. Video gaming was found to be linked with higher aggression and also problems with general behavior. Norton and now offering their scam Genie AI as a free app in chat GPT with the details were joined by technology editor Alex harrav Royt from Tech Advice Start Life. Norton announced some they called Morton Genie. This would have been sometime last year. It's an AI scam detector that at first you could download on iPhones and that become available for androids, and it helped end users to determine whether you know from a screenshot of an SMS message or some sort of message of social media or elsewhere like an email, as to whether or not what you were looking at was a scam or not, whether the AI engine inside this app could detect that something was malicious. And we all know that the bad guys are using AI to fake websites to eliminate the telltale spelling aeras to completely clone a site and make you think that when you're logging in and giving them using every password and maybe even the two factor authentication code that somebody else will immediately type into hacking to you for real is legit and looks so real. So people have been turning to AI, not just with the Norton Genitol, but into chatjibyt and Gemini and others to ask the AI whether something is a scam. And this is because people have been asking Google for years about medical conditions and they now ask AI. They treat a like a doctor, a financial advisor, and e fisionist, a therapist, psychologist, and we often see where it says I am not a doctor, please seek propabetical advice. But here's my answer. So the interesting thing here is that chatjibt can be used for free, and so can the Norton app. And often when you have these more advanced facilities, you've got to pay twenty bucks US a month for chat rebt or thirty three dollars. But here you can download the Norton Genie app into CHATWBT, even the free version, and then you can ask it at you put the aximably, you put Norton this email says my account will be locked if I don't act now. Is this a scam? Or at Norton. I've got a text about a missed delivery with a link. Should I click it? Or at Norton this message looks like it's from my bank, but something feels off. Is this the real online deal or are they trying to steal my information? And there are tools that only check whether a link is known to be malicious, but the Norton Genie app is looking at the full context of a message, and it's examining the language, the intent, and the tactics that are being used alongside URL and the main checks to spot common scam patterns like impersonation, which they're always trying to do. The pressure to act quickly, which is scam, is tool in trade. They want you to You've got to act now, and then you're told to go and buy an Xbox game card to pay off a texted or something. It's ridiculous, but people fall for it or request for sensitive information. So you just lock into CHATGBT, you open the apps section you find and enable Norton, and then when you want to ask Norton something, you are at Norton and then ask the questions. So it's nice to see the good guys are using ad to help us fight against the bad guys using AI. That's Alex aharov Royt from Take Advice dot life and. This is Spacetime and that's the show for now. 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