Astrum Space - Something Strange Is Hiding Beyond Our Solar System

Episode Date: October 30, 2025

In this Astrum episode, we’re venturing out beyond the edge of our solar system, to discover what else lives in our local neighbourhood. Do we live in an especially strange place in the cosmos?This compilation includes some content from the early days of the Astrum channel - keep watching to see Alex on camera!▀▀▀▀▀▀Astrum's newsletter has launched! Want to know what's happening in space? Sign up here: ⁠https://astrumspace.kit.com⁠A huge thanks to our Patreons who help make these videos possible. Sign-up here: ⁠https://bit.ly/4aiJZNF

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Plus, unlimited plans started $35 a month. Now that's a deal that doesn't stay. Explore GoogleFi Wireless plans today. Plus taxes and government fees. GoogleFi Wireless is not subject to data traffic deprioritization during times of high network usage. When 15 supernovae go off close together, both in time and proximity, it makes quite a bang. It should be of no surprise that such a violent event should fundamentally transform the region of space around where it occurred. Interstellar dust was swept aside from the forces of those concurrent blasts, creating

a monumental void of low density matter, and a shockwave that continues to hurtle across the galaxy to this day at a rate of 6 km a second. In its wake, plasma, reaching 1 million degrees Celsius in temperature. This simultaneous Swiss cheesing and heating up of the interstellar medium, the interstellar medium is what is now called a hot bubble, and represents both the end of stars and their beginning. But this is not some distant structure that lurks in a faraway corner of the universe. Our solar system isn't even heading right towards it. We are in it, charging for its point of origin head first.

Welcome to our local hot bubble. What scientists now realize is the local environment that exists around our solar system. It is a neighborhood we are still exploring, but its nature is becoming clearer and clearer. So what do we know about the local hot bubble? How did it form? And what more is there to be discovered? I'm Alex McColgan and you're watching Astrom. Join me today as we walk in the aftermath of Explore.

exploding stars, and discuss how scientists even determined we were in the heart of a cataclysm to begin with. The local hot bubble was not always something we knew about. First identified in the 1970s from observations of low-energy x-ray emissions that were detected over the entire sky, the local hot bubble was hypothesized to be a large cavity in the interstellar medium, called a super bubble filled with the air. tenuous, million degree, low density gas. In the 1990s, scientists found that X-ray emissions could happen anywhere neutral atoms interacted

with the solar wind, challenging the idea that the emissions must point to a large hot bubble. But soon, evidence would reveal that the hypothesis from decades earlier was indeed correct. In 2014, NASA confirmed the existence of the LHB through the diffuse X-ray emission from the local galaxy mission, known as DXL. While soft background radiation can come from other sources, like from comets, for example, the mission found that only 40% of the fog of low energy x-rays came from within our solar system. This affirmed that the dominant source was diffuse X-ray emissions

emanating from the million-degree region of interstellar plasma, known as the LHB. Although this confirmed the bubble, questions remained about what could create such a massive void, and what might explain the thousands of surrounding young stars. The prevailing answer proved to be both violent and fascinating. Recent research suggests that their local hot bubble was the aftermath of around 15 supernova explosions that occurred sequentially within a span of a few million years, erupting in relatively close proximity to one another. Scientists estimated that the first of these massive stellar explosions went off roughly

14 million years ago, each expelling enormous amounts of energy, pushing out the surrounding interstellar material and heating the remaining gas to extreme temperatures. Evidence of these ancient explosions has been preserved in our Earth's geological record in deep sea sediment deposits, in the form of a special isotope called IN60. This radioactive isotope can come from a few different sources, but the most common source of iron 60 is believed to be supernova explosions. We know that the source of the isotope is extraterrestrial, because the Earth itself has no way of producing iron 60 on its own, and matching deposits have been found on the moon as well.

The reason that this radioactive isotope is special is because we know how long its half-life is. We know that it decays into Cobalt 60, another radioactive isotope, before it finally decays into nickel-60, a stable element. Iron 60 has a half-life of 2.6 million years, and cobalt 60 has a fairly short half-life of just 5.3 years. Because of this, when we find a deposit that contains these elements, scientists can compare the amounts of iron 60, cobalt 60, and nickel 60, like an elemental clock, to reveal when that material was deposited on our planet. And luckily for us, international research teams have found several such deposits over the

last couple of decades. In 2016, iron 60 deposits were found in deep sea cross samples taken from the Pacific, Indian and Atlantic oceans, indicating two distinct spikes in the radioactive debris, appointed to several supernova events in the not-so-distant past, and not too far from our solar system, just 326 light years away. The sample showed a spike of iron 60 between 3.2 and 1.7 million years ago, and another spike between 6.5 and 8.7 million years ago. Nuclear physicist Anton Walner, who led one of these research teams studying the deposits,

said that the fact that the more recent debris was spread across 1.5 million years suggests that there were a series of supernovae that occurred one after another in close succession. physicist Dieter Breitchevirt, who led a second team of scientists, identified a likely source of these supernova explosions, which would have occurred 196 to 423 light years from the sun. These supernovae that created our local hot bubble may have been part of an aging star cluster, whose surviving members are now associated with the Scorpius Centaura stellar group. the iron 60 deposits, the team was able to trace the signals of two supernovae, one that

happened 1.5 million years ago and the other 2.3 million years ago, as the result of the deaths of stars that were 8.8 times and 9.2 times the mass of our sun, respectively. In fact, our LHB is still growing today, albeit much more slowly than when the supernova exploded millions of years ago. The speed of expansion has plateau at about 6 km per second now, according to astrophysicist Catherine Zucker, in 2022, Zucker authored a groundbreaking paper that reconstructed the evolution of our galactic neighborhood, tracing the chain of events that created our local hot bubble and led to the formation of all the young stars we see nearby today. From there, they made an incredible discovery.

Using data from the European Space Agency's Gaia Telescope, Zaka and her team were able to construct a 3D space-time map, showing that within 500 light years of our planet, all of the young stars and star-forming regions reside on the surface of our local hot bubble. With these 3D positions and the 3D motions of the stellar clusters, they traced back 20 million years of star formation history near our local hot bubble. The implications were clear that all of the well-known star forming regions near our solar system had formed along the outer edge of the local bubble as it swept up gas during its expansion. Stellar nurseries are a field we are learning more about all the time, particularly as new images

are taken by our telescopes. is a spectacular image of the Chameleon One Dark Cloud, one of our nearest stellar nurseries, taken by a dark energy camera on the Victor M Blanco 4-meter telescope at Chero-Tololo Inter-American Observatory. By studying the propagation of starlight from within it, scientists can tease out details about how stars form, which might help us better understand the local hot bubbles impact on our galaxy today. You might not have seen this particular image before, as new space news is coming out all

the time, but I've talked about it in my newsletter, which I've recently launched to help you keep up with all the breathtaking photos released by our many telescopes on Earth and in orbit, or new breakthroughs that reshape how we understand the cosmos. You should sign up to never miss the most exciting news, even if the headlines do by following the link in the description below. There are new editions that come out every Thursday. From the local Hot Bubbles birth 14 million years ago, Zucker and her colleagues identified four epochs of star formation on the bubble shell.

Starting about 16 million years ago, we see the birth of the upper Centaurus Lupus, or the UCL star cluster, followed by the lower Centaurus Crux, or LCC star cluster. These formed about 49 light years apart from one another, and about 14 million years ago, these stellar populations were the source of the stars that went supernova to create our local bubble. About 10 million years ago, we see the first of the four star-forming epochs after the formation of the LHB, the Upper Scorpius Association, and older Othiukas stellar populations are born in the first epoch. Six million years ago, the second star-forming epoch formed Crona Australis and the older stars of Taurus. Then, around 2 million years ago, the stars in

lupus and chameleon, as well as younger stellar populations of Taurus and of Eucas, came to be in the third epoch. And finally, our present time falls within the fourth star-forming epoch. We can observe the dense star-forming molecular gas that surrounds the LHB, which will eventually lead to more star clusters being born along the bubble's outer edge. With all of this stellar creation, you might be surprised to learn that we are interlopers. Our sun did not form inside the local bubble. In fact, the sun was about 978 light years away. when the first supernova went off in UCL and LCC, only joining up with the LHB about 5 million years ago as its path through the galaxy took it into the bubble. With the trajectory shown in

yellow dots, you can see our son's location just before it entered the bubble, and now, just by coincidence, our son happens to be located near the center of the LHB. Drifting into the heart of what was once a raging furnace, scientists became interested in mapping out the ongoing temperature within the local bubble. You might wonder why we're so calm if temperatures of plasma here can reach 1 million degrees Celsius. The key lies in that plasma's density. Look, this 3D map from Zucker's 2022 publication shows our local hot bubble in dark blue.

The density inside our bubble is extraordinarily low, containing about 100 times less hydrogen than the typical interstellar medium. So while the temperature of this gas soars to around 1 million degrees Kelvin, giving rise to the diffuse X-ray emissions we have observed around the whole sky, we don't have much to worry about. Tracking temperatures within the local bubble has provided more evidence of its existence. The extended REN-Gen survey with an imaging telescope array, better known as the E-Rosister X-ray telescope, has been able to gather the most detailed all-sky survey of soft X-rays to date, and that data has been used to map the LHB and our solar neighborhood in much

more detail than before. Launched aboard the joint Russian and German mission Spectrum REN-G in 2019, and Data from the E-Rosita X-ray telescope has allowed a team of scientists led by the Max Planck Institute for extraterrestrial physics to create a 3D map of the LHB and identify a temperature gradient where the Galactic South was slightly hotter than the Galactic North. This temperature dichotomy could be explained by supernova explosions in the past few million years. And by creating this bubble map, the team also found that the LHB is shaped by the stretched out towards the poles of the galactic hemisphere.

This is because the hot gas in the bubble expands out in the direction with the least resistance, which happens to be away from the Milky Way's galactic disk. Along with identifying temperature variations and the shape of the bubble, the team compiled this and other data to create an even more detailed map of our galactic neighborhood. In the new 3D map, our local hot bubble looks like a 3rd. three-dimensional splatter, surrounded by, and even overlapping, other galactic structures. These other structures represent known supernova remnants, like the gum nebula shown here in red, and dense molecular clouds, shown here in orange.

With the new data and 3D maps, these super bubbles seem likely to be common in our galaxy, creating a Milky Way that's sort of like Swiss cheese. The cavities of our Swiss cheese galaxy are blasted out by gigantic supernova explosions, with new stars forming along the edges of the holes created by dying stars. And like Swiss cheese, it appears that some of these super bubbles may have tunnels connecting them to other bubbles or other structures, suggesting our local hot bubble could be part of an intricate network of similar features throughout our galaxy. For example, we have the Canis Majoris Tunnel, which lies on the Milky Way's Galactic Disc,

and is believed to connect our local hot bubble to the Gum Nebula, or another larger nearby super bubble. But the 3D map also revealed another, previously unknown interstellar tunnel, stretching towards the constellation Centaurus, possibly connecting our local bubble, to the neighboring Loop 1 Superbubble. While these interstellar tunnels are tantalizing, our current understanding of them is limited. Nevertheless, these tunnels of hot gas and bubbles of star formation

shaped by the death of gigantic older stars has me in awe of how powerful and interconnected the evolution of our local galactic neighborhood really is. It suggests that stars are are not just born and die in isolation, but that their energetic output continues to mold the environment for millions of years after their demise. And as our observational tools become more sophisticated,

we are beginning to uncover the extent of these hidden structures. So next time you look up at the night sky, you might remind yourself that we are surrounded by crazy patterns, just like our local bubble in the Milky Way, that was carved out by ancient cataclysms, and that some of those stars that you see are actually plastered along the walls of a supernova blasted cavity,

which connects to other parts of the galaxy through interstellar tunnels. Wow. Imagine for a moment that you're looking out your window when a singular bright light suddenly flares into existence in the sky above you. This dazzling star is, as luminous as the full moon at night, perhaps brighter, and is even visible during the day.

If you can see the light, you might already be in trouble, as that unexpected star is now flooding the atmosphere of the earth with a catastrophic dose of gamma radiation and x-rays, stripping away our ozone layer and exposing us to the full fury of the sun's deadly radiation. And on its way, jettisoned out at 10,000 to 40,000 kilometers per second, a cataclysmic wave of stellar matter and debris hurdles towards our planet. The dying roar of an exploding star venting billions of tons of burning mass at us, ready to sweep across our planet's surface in a tidal wave of fire. This is a supernova, or at least it's one interpretation of what we might see. if one were to occur near us. But how likely is it for this to actually happen?

What constitutes near us on a cosmic scale? How close would a supernova blast have to be before life on Earth would be threatened? What might we on Earth actually experience? And what stars near us have the potential to detonate in this way? I'm Alex McColligan and you're watching Astrom. Join with me today as I discuss an event that could be an armaged. get in our lifetimes, or could be nothing more than a pretty twinkle in the sky.

Let's start with the good news. Supernovae in our galaxy are not that common. While astronomers observe hundreds of supernovae every year outside our galaxy, this is mostly a reflection on how many galaxies there are in the universe. Closer to home, though, within our own Milky Way, we likely only see about two to three every century. This means that the other odds of one going off tomorrow are not that high. But they're not impossible, and according to archaeologists, the Earth has likely been hit by a supernova before in the course of its 4.5 billion years of existence. For starters, we exist in an area of space known as the local bubble, a relatively sparsely populated

region of interstellar space about 1,000 light years across that is thought to have been carved out by a supernova detonation 10 to 20 million years ago. which our planet would have been around for. I talk about that in another of my videos which you can see here. Scientists have found evidence of another detonation that happened two and a half million years ago due to a high concentration of iron 60 and manganese 53 in a particular layer of the geological record. This supernova happened far enough away to be harmless to us, but this might not always

be the case. There are some scientists who believe that the extinction of woolly mammoths was caused by a massive piece of debris from a supernova crashing into the planet about 13,000 years ago. The impact site in question had magnetic sphules and radioactive potassium 40, a substance found in supernova ejector. A smoking gun in the era of most mammoths went extinct. Even before that, mammoth tusks from 34,000 years ago were found containing tiny impact

craters from grains of slightly radioactive iron. been travelling at 10,000 kilometres per second. If you can recall, that was one of the potential speeds supernova explosions travel at. That can't have been a nice experience for the mammoths in question. An astute observer from this might be able to note an important fact, however. Evidently, if life began on Earth about 3.7 billion years ago, we faced three supernova explosions that have impacted us in the last 20 million years, and life is still life, largely ticking along, my condolences, woolly mammoths, if you did die out from one of these,

then Supernovae as a whole can't be quite as destructive as my opening introduction made them out to be. And that's largely true, although it is, of course, a question of proximity. If I'm 1,000 kilometres away from a nuke going off, I have little to fear, but it's a different story if one detonates on my coffee table. when it comes to supernovae, it turns out that the universe has relatively large coffee tables. To understand the scale of these explosions, it's necessary to understand the forces involved, which means we need to understand a little better about how supernovae happen.

It turns out that there's two main paths stars can take to get to that explosive grand finale, although in each case it has to be the right kind of star. For the first path, resulting in a Type 1A supernova, it usually needs to be a white dwarf in a binary system that's gradually or speedily siphoning matter away from its neighbouring star until it reaches a point of critical mass. This path is not fully understood, but it's thought that a white dwarf, or a dense star comprising of mostly carbon in a giant super diamond core, is normally finely balanced between two powerful opposing forces, electron degeneracy pressure and gravity.

This simply means that atoms usually object to being squashed too much. Their electrons like to remain at certain distances from the nucleus of the atom, and will resist being pushed denser than this point. But gravity is an incredibly powerful force that seeks to draw matter closer, particularly in a dense mass like a white dwarf, where a section the size of a sugar cube has the mass of around a car. And in a binary system where the white dwarf is absorbing more and more matter from its neighbouring star, eventually gravity overwhelms electron degeneracy pressure and the whole house of cards collapses at once.

Carbon fusion begins. Within a few seconds, most of the star undergoes fusion, forming into heavier elements and releasing a whole lot of energy as the matter in the star starts. settles into its slightly more efficient new configuration. How much energy? Around 1 quarter-rortar decillion joules. That's 1 followed by 45 zeros. If you claim you knew that number before, you're almost certainly a liar.

All of this energy is released in just a few seconds. So naturally, the star ejects its entire contents out in all directions, sending it travelling at 6% the speed of light and unleashing a flood of mostly gamma radiation out across the galaxy. The brightness of this event is 5 billion times brighter than our sun, and burns for a few weeks until the ejector has travelled far enough that the overall energy level has started to dissipate. The second type of supernova, type 2, is similar, except instead of involving a white dwarf, involves a massive star, at least five times more massive than the Sun, at the end of its lifetime.

These stars are still burning brightly, and rather than just electron degeneracy pressure, it's also the heat of fusion that keeps the star in balance. However, just like a Type 1A supernova, eventually balance collapses. This time is because the star runs out of fuel, and without this additional fusion energy pushing the star's mass outwards, electron degeneracy pressure on its own can't cope with the star's weight to similar effect. The only difference is that while some of a massive star will remain, often collapsing down into a neutron star or a black hole, white dwarfs usually vanish completely. Either way, the scale of material and energy released by supernova is vast, so vast that unsurprisingly,

anything immediately next to it is not going to last long. This is an energy powerful enough to rip apart a star. A planet is going to have no chance if it's in the immediate vicinity. Our own sun, thankfully, will never go supernova, as it's not massive enough, but if it did, there is a good chance the Earth would be either partially or completely vaporized. Its rocky exterior reaching a boiling point thanks to temperatures 15 times hotter than the surface of our sun and being whisked away in the weeks of the supernova's passing. What is surprising, however, is how quickly this first wave of devastation would dissipate with distance. Indeed, vaporization is realistically not the largest threat supernova poses.

In 2011, experts from the University of Cambridge calculated that, Even planets orbiting their star at the distance of 15 billion kilometres, or about 100 times the distance between the Sun and the Earth, would remain intact and would instead simply be sent flying out into space now that there was nothing much left to orbit. Of course, such a planet's hypothetical ecosystem would probably have different problems to worry about. Things would get very cold very quickly. Of course, even if the crust of a planet itself remained intact, that doesn't mean that

life on said planet would be sustainable. Ignoring the light of a supernova outperforming the brightness of an entire galaxy sometimes, leading to blindness for anyone who saw it, simply stripping away our atmosphere would carry problems. High levels of radiation, even if it didn't affect us directly, would alter the chemical composition of our atmosphere, negating our ozone layer, vast, increasingly increasing our odds of dying of radiation poisoning, and killing off phytoplankton in the ocean, and causing mass extinctions, as the consequences of that worked its way up

the food chain. Scientists put this kill zone to be within 25 light years. Beyond that, the fury of a supernova begins to calm, as distance causes it to wear itself out. Although admittedly, the asteroid that potentially killed the mammoths came from a supernova that was 250 light years away, if it happened at all, it was likely bad luck. Generally speaking, we wouldn't notice any damage from a supernova this far away, its radiation levels wouldn't be high enough to cause mass extinctions. By 500 light years, we'd hardly notice the event at all, other than perhaps seeing a brighter star in the sky.

Which leaves one important question. In 300 light years, are there any supernova candidates we need to worry about? Thankfully, scientists are fairly confident that the answer is no. Massive stars are very noticeable, and the only two that are at risk of going supernova are Beeljuice and Antares. Both of those are more than 400 light years away. White dwarfs are a little trickier, thanks to their diminished brightness. been conventionally hard to spot, making it harder to predict whether we might be at risk

from them. However, in 2013, Issa's Gaia Space Observatory released a massive packet of information in its efforts to map the stars that allowed scientists to identify 13,000 white dwarf stars within 326 light years of us. Thankfully, in spite of this large number, scientists remain confident that none of these are scheduled to explode anytime soon. meaning within the next few hundred thousand years. Speaking of Beetlejuice, there are some scientists who predict that this red giant might detonate

much sooner than that, perhaps within the next few decades. Their research works under the assumption that Beetlejuice has a much larger radius than previously predicted, but if it's true, it might mean that we would get to see a local supernova within our lifetimes. Of course, according to some models, we would have not. nothing to worry about. The shockwave travelling out from Beetlejuice would take some time to get to us, and even once it arrived, it would be travelling with less force than the push of the solar wind. In other words, it wouldn't be our magnetosphere or atmosphere that kept us safe. The

protective sheath of the sun's heliosphere would be enough to keep such a supernova obey. So, there you have it. While supernovae are perhaps some of the largest explosions in the universe, Through some fortunate stroke of luck, our patch of galaxy has nothing really to fear from them. The odds of us being hit by even the neighbouring stars like Beetlejuice that are scheduled to go supernova are incredibly small. True, Earth has plenty of cataclysms of its own, such as floods, earthquakes and hurricanes that can bring devastation to a community in a heartbeat, and space is still a dangerous place. But it's nice to know that of all the things we have to worry about,

we can probably cross planetary annihilation from supernova off our list. The universe is full of secrets, and some of the most incredible ones are hiding just beyond the reach of visible light. What if I told you that more than 1.5 billion unseen objects, from galaxies and newborn stars to some of the oldest stars in our entire galaxy, are sitting just out of reach of us, cloaked in cosmic dust. It's a little frustrating to think about, isn't it? Until now that is, because thanks to the European Southern Observatory's visible and infrared survey telescope for astronomy, better known as Vista, we can finally lift the veil on these hidden wonders.

For the first time in human history, we have a pretty comprehensive infrared map of the Milky Way, one that pierces through the obscuring fog of space to reveal an unprecedented view of our galaxy and what lies beyond. I'm Alex McCulligan and you're watching Astrum. Join me today as we appreciate how this first-of-its-kind map was made and take a look at some stunning images that reveal previously unknown stars across our galaxy. No one goes to Hank's first spreadsheets. They go for a darn good pizza. Lately, though, the shop's been quiet.

So Hank decides to bring back the $1 slice. He asks Copilot in Microsoft Excel to look at his sales and costs and help him see if he can afford it. Co-Pilot shows Hank where the money's going and which little extras make the dollar slice work. Now, Hank has a line out the door. Hank makes the pizza. Co-Pilot handles the spreadsheets.

Learn more at M365Copilot.com slash work. Real value, shows up in reliability, you don't have to second guess. Like a set of Firestone all-season tires. They're designed to deliver confidence-inspiring wet weather traction and a quieter ride, no matter the road, season after season. Firestone all-season tires. For durability, you can count on, just like people count on you. Firestone, always dependable since 1900. In September 2024, Vista published the largest and most detailed infrared survey of the Milky Way ever undertaken. Encompassing a 13-year period from 2010 to

2023 across 140 nights of observation, this project has captured around 200,000 images and generated 500 terabytes of data. That's the same amount of data as it would take to stream a 4K video for nearly three years straight. Vista is part of the of ESO's Paranel Observatory located in Chile, with its main focus being to map large areas of the sky. Using Vista's infrared camera, known as Vercam, the team was able to peer through the dust and gas that permeates our galaxy and uncover some of the Milky Way's most hidden places. Traditional telescopes allow us to view space in visible wavelengths, which range between about

380 to 700 nanometers. But Vista isn't like traditional telescopes. Instead of relying on visible light alone, Vista operates at infrared wavelengths between 900 and 1,200 nanometers, allowing it to detect otherwise invisible objects like stars obscured by dust and cold brown dwarfs, also known as failed stars, which don't emit enough visible light to be seen with a traditional telescope. To get an idea of the difference between visible and infrared light, take a look at these two images of the Lobster Nebula, or NDC 6357, one taken in visible light and the other

with Vista's telescope. We can see that in the infrared, the dust that obscures our field of view seems to disappear, revealing what looked like hundreds of thousands, or maybe even millions, of previously invisible stars. The map was created through Vista variables in the VALactia, or VVVVVS survey, via lactea being the Latin name for the Milky Way, and its companion project, the VVVVE extended survey, or VVVVX. The data collected from these two companion projects that make up the Vista infrared service, survey have already led to the publication of more than 300 scientific articles.

Unlike other recent space maps, this is one of the most detailed ones ever made. It's the first infrared survey to cover nearly 80% of the Milky Way's luminous mass, and provides the largest infrared catalog ever made of our galaxy's central region. It allows astronomers to study our galaxy in finer detail than ever. ever before. This survey gives us an accurate 3D view of the inner regions of the Milky Way, which were previously hidden by dust. It covers an area of the sky equivalent to 8,600 full moons and contains about 10 times more objects than any previously published infrared map from 2012. Our Milky Way consists of a central bulge, a dense, bright, puffed-up collection of stars,

with a flat disk of two spiral arms wrapping from the ends. This image shows the area of our galaxy that was mapped in the survey. The red squares mark the central regions of the galaxy, which were observed by the original survey, and then re-observed again by the extended survey. And the other square colours show areas that were only observed as part of the extended survey. From this image, you can see that these surveys have focused

right on the central plane of our galaxy, spanning part of the disk and most of the nuclear bulge. But what has Vista revealed? Argentinian astrophysicist Dante Minuti, who led the survey project said, we've made so many discoveries, we have changed the view of our galaxy forever. And as much as I'd love to talk about all of them in this video, it's probably best I stick to some of the highlights. As part of the survey in 2015, Vista turned its attention to the star formation region of Messier 20, also known as the Trifid Nebula, which lies about 9,000 light years from Earth. Viewed invisible light in this image, we can see a beautiful nebula, glowing pink from the

emission of ionized hydrogen, and surrounded by a blue haze of scattered light from young hot stars. The cloud of gas and dust is obscuring the star. star-filled space behind it. Now look at this second image taken by Vista's infrared camera. Peering beyond the clouds reveals a whole swarm of new stars. This image not only allows us to see through the Trifid Nebula, but by chance it revealed objects on the far side of our galaxy that had never been seen before. To their surprise, astronomers identified two faint, reddened objects as sea-feed variable stars.

While they appear in the image to be just behind the edge of the Trifid Nebula, in reality they are very distant, about seven times farther than the nebula that once helped to block them from our view. Seafeed variables are a type of bright star that is unstable. They brighten and fade over a period of a few days or a few months. depending on their brightness. The first variable star we ever identified in modern times was Omricon Setti, also known as mirror. It had been described as a Nova until 1638 when Johannes Hallwoods observed it getting brighter

and dimmer in a cycle that lasted 11 months. As for this pair of newly discovered stars, they are the only sea-feed variables that we have identified so far in this location. which lies beyond the central bulge on the far side of our galaxy. And they can be really useful too. You can think of them as a kind of cosmic yardstick that can be used up to distances of tens of millions of light years. If you know how long the star's pulsation period from bright to dim is,

then you can infer its absolute brightness as well as its age. You can compare absolute brightness to the apparent. brightness, that is, the amount of light that reaches Earth, so you have a measure of how distant the star is. With a few reference points like these, we can build up a real picture of the scale of our galaxy and beyond. Looking toward the galactic center, a team of astronomers and data scientists found even more candidate sea feed stars, 655 in fact.

They then sorted these into one of two classes, and found that 35 of these 655 stars were classical sea feeds, the younger of the two. This was really exciting, especially since the Galactic Bulge was thought to contain mostly elderly stars that are at least 8 billion years old. Recording their pulsation periods, the team revealed that all 35 of these sea feeds were less than 100 million years old, and some of them may be as young as 20 billion years old. some of them may be as young as 25 million years old. To put that in context, our own son is about 4.5 billion years old, so the youngest sea feed

has only been around for 0.6% of our son's lifespan. The team's exploration of sea feeds culminated in another major discovery. By mapping the 35 classical sea feeds they found, the team was able to trace a completely new feature in the Milky Way. a thin disk of young stars that stretches right across the galactic bulge. Buried behind thick clouds, it had remained unknown in all previous surveys of the region. In revealing this structure, combined with the discovery of older sea feeds, as I mentioned earlier, scientists have inferred that there has been continuous star formation along the midplane of the galaxy

for the past 100 million years. There might also be even younger sea feeds, that we haven't seen yet, as these stars would be so bright that they would be saturated in the VVV survey. The fact that we found this thin disk of young stars within the galactic bulge is incredible. We used to think that the galactic bulge was an ancient feature of our galaxy's past, where exclusively old stars had formed separately from the stellar disk, but this finding reveals that things aren't so black and white.

and that the formation of newer stars within the bulge could be a natural progression of our galaxy's evolution. But, even more inspiring perhaps, is a discovery by the Vista Infrared Survey that lies at the ancient heart of our Milky Way galaxy. In 2016, for the first time, a type of ancient star known as R.R. Lairay, another variable star was discovered in the center of the Milky Way. galaxy by a team led by astrophysicist Dante Maniti and Rodrigo Antreirae Ramos. This type of star is usually found in globular clusters, which tend to orbit the outer regions of the galaxy. A globular cluster is a tightly packed group of stars that contains tens of thousands to millions of stars bound together by gravity. They're also really ancient, containing a stellar population that can be over 10 billion years old.

The team found 12 RR Lairay stars during the VV survey, which suggests that they might be the remnants of an ancient globular cluster right at the heart of our galaxy. This finding also provides evidence that might help astronomers to decide between the two competing theories of how nuclear bulges form. While some scientists think that the nuclear bulge forms early in the galaxy, the galaxy galaxies evolution, when multiple smaller galaxies violently collide, others say that it forms gradually over time, where gas is funneled inwards to trigger star formation. Finding these ancient stars here suggest that the bulging center of the Milky Way likely

grew through the merging of primordial globular clusters, therefore supporting the first theory. So not only does it hint at our own galaxy's beginnings, but it also offers comparison telling evidence into how these galactic bulges might form in other similar galaxies. Speaking of ancient stars, Vista was able to find two new globular clusters as part of the infrared survey in 2011. In this visible light image, a known globular cluster, U.K.S. 1, can be seen on the right as a hazy red splotch. This cluster had been the dimest known globular cluster until the new discoveries.

Now, compare this same patch of sky, but this time in vistas infrared light. Suddenly, we can see what we have been missing. Much more faint than the known U.K.S. 1, we can make out a second globular cluster, this time in the upper left of the image, which has been named VVV-CL-001. Another globular cluster, aptly named VVV-CL-002, was found soon after, and this small, faint group of stars may be the closest known globular cluster to the center of the Milky Way. Did you know that there were only 158 known globular clusters in the Milky Way before these new ones were found by Vista?

For the survey to identify two more of these rare stellar objects is quite a significant. significant accomplishment. Within this central region of the galaxy, it's easy for younger stars and cosmic dust to obscure globular clusters, especially since their age prevents them from shining as brightly. But now that they've been revealed, these features bring exciting possibilities for further study. It could just be an illusion of perspective, but scientists have wondered whether VVVVCL001 is gravitationally bound to UKS1.

If this is the case, then they would be the Milky Way's first known binary globular cluster pair. We found binary clusters in other galaxies, like in Centaurus A and the Large Magellanic cloud, but scientists think it might be when these gravitationally bound clusters collide that we get the most massive globular clusters, like Omega Centauri. So studying a binary cluster right in our own galaxy. galaxy could produce some amazing insights into this process. It's all speculation at the moment, but it's definitely cool to think about. In addition to globular clusters, the Vista Infrared Survey identified a multitude of other

types of star clusters. At least 96 new open or galactic clusters have been found, which typically contain fewer, younger stars and are much more common than the globular type. the globular clusters, they have been hidden by cosmic dust, but Vista's 4.1 meter infrared telescope has lifted the curtain to show them in all their glory. Take a look at just a few of these stunning images we now have of these objects. One of these open clusters, VVVVCL003, is much more difficult to make out in images compared to the tightly packed globular clusters.

and see the density differences in the stars in this section of the image compared to the surrounding regions. It was found by Vista 15,000 light years beyond the Milky Way Center and also happens to be the first of its kind to be discovered on the far side of the galaxy. The sheer scale of this survey is staggering. Covering a vast region of the sky and mapping more than 1.5 billion objects, this data has already led to fascinating discoveries that are rewriting our understanding of the Milky Way and beyond. And that's just the tip of the iceberg.

This survey will serve as a foundation for future telescopes and observations, which will hopefully be able to expand on Vista's legacy with even higher resolution and sensitivity. We now have the most detailed 3D map that has ever been made of the Milky Way structure and objects, one that unveiled hidden wonders previously beyond our reach, and scientists are already uncovering new galactic features and reshaping our understanding of the galaxy. With the information from this groundbreaking infrared survey, as well as the recent work from Issa's Gaia mission in visible light, it's an exciting time to be an astronomer,

and we can expect a flurry of new insights about our own galaxy and the universe as a whole. The Earth's infrared observations have unveiled dozens of hidden star clusters and millions of previously unseen stars. They have revealed new stellar nurseries where stars are born, and they have broadened our understanding of the formation of our Milky Way. Looking at the sky through different wavelengths has brought about a new era of galactic exploration, and I can't wait to see what else astronomers and data scientists are going to uncover thanks to Vista's 3D map.

Some of you may remember my first video I ever did on my channel, which was how big is our solar system if the sun was the size of a football or a soccer ball. Today I'm going to do that again but this time I'm going to scale it down a little bit where the sun is only the size of one millimeter like a grain of sand. We're going to see how big the solar system is in comparison to the sun being that big. So we'll start off first of all with the sun. I'm going to put it just by here. Now the closest planet to our sun is of course Mercury. And if the Sun was 1mm in diameter, that would mean Mercury is 4 cm away. So I'm going to put it just by there.

There's Mercury. So the next closest planet to the Sun is Venus and it is 8 centimeters away. So there we have Venus. The next one is us on Earth and that is 10 centimeters away. Then we have Mars, which is 16 cm away. The next one we'll mention here is Sarah, the dwarf planet it found in the asteroid belt. And that is 30 centimeters away. Okay, the next one is Jupiter and that is 56 centimeters away.

We're getting far away. Saturn is 1 meter and 3 centimeters away. Coming to the first of the ice giants now, we find Uranus, which is massive, 2 meters and 6. centimeters away. The last real planet in our solar system is Neptune and that is 3 meters and 24 centimeters away. And then we have Pluto which is 4 meters and 22 centimeters and this is the last thing that we'll look at in our solar system. At this point you may be wondering, but what about the closest star Alp of Centuri? Well you're gonna have to follow me a little bit so come on let's go. You say this place was steps from the water

We just haven't found the steps yet. How much did we save? Enough. Enough to get lost. Or you could book a stay with Hilton. Welcome to your oceanfront room. Just steps from the water. The Hilton sale is on now.

Book on Hilton.com or the Hilton app and save up to 20% to get the stay you expected. When you want savings, not surprises. It matters where you stay. Hilton for the stay. When you need to build a bill, up your team to handle the growing chaos at work, use Indeed sponsored jobs. It gives your job posts the boost it needs to be seen and helps reach people with the right skills, certifications,

and more. Spend less time searching and more time actually interviewing candidates who check all your boxes. Listeners of this show will get a $75-sponsored job credit at Indeed.com slash podcast. That's Indeed.com slash podcast. Terms and conditions apply. Need a hiring hero? This is a job for Indeed sponsored jobs. I know this wasn't really a straight line. But yes, Alpha Centuary, if the sun was the size just one millimeter, Alpha Centurie is 30 kilometers away. And that's our closest start. Thanks for watching.

This video was in part made possible by all the astromnauts on Patreon. If you think these videos add some educational value to the world and want to give them more stability than the algorithm, you can become a paid member on Patreon to contribute towards their creation. When you join, you'll be able to watch the whole video ad, free, see your name in the credits, and submit questions to our team. Just sign up with a link in the description. Meanwhile, click the link to this playlist for more Astrom content. I'll see you next time. Yamava Resort and Casino at San Manuel is California's number one entertainment destination for

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