EVSN - Repainted Rose, Worlds Colliding & White Dwarfs of Unusual Size

Welcome and personal updates

0:00It's the 365 Days of Astronomy podcast, coming in 3, 2, 1.

0:30Hello, everyone, and welcome to what is somehow only episode 3 of season 5 of Escape Velocity Space News. This season has not at all been what we intended. For those of you watching this on YouTube or Twitch, I am clearly not in my studio. I am, in fact, coming to you from the spare bedroom of a friend's house. One of my close friends had a bone marrow transplant, and not all went well. So I have

1:04flown out to points undisclosed and stolen a computer monitor, and I am recording on the first day I've had in weeks where I'm not sitting at their bedside in the hospital. To all of you who have stayed with us over on Patreon, to all of you who have sent messages through social media, I really appreciate all of the support you have provided. Things should be slowly returning to

1:36something more closely resembling normal soon. I'm out here for one more week. I am then going to fly home, record frantically. Then I am off with Aviva Yamani, one of our other project directors here at CosmoQuest. She runs the 365 Days of Astronomy podcast and is one of the people behind the scenes for AstronomyCast. She and I are going to be meeting up in Japan for the International Astronomical

2:07Union Symposium 409 where we are both presenting on technology and science communications, which is kind of the thing we do here. Before I get to go and see Aviva and present at a conference in Japan,

Comparing Spitzer and JWST nebula images

2:26however, I do have science news to share. And I'm going to start with this image. When I first saw this a couple of weeks ago, I was completely confused. I had no idea what I was looking at. I showed it to my friend who was in the hospital because it's a pretty picture and you cheer people up. And I'm like, I don't know what it is, but it's sure pretty. And much to my confusion, it turned

2:58out this is NGC 7129, an object I absolutely love and had previously come to know through the Spitzer Space Telescope version of the image. And the wild thing about using both the James Webb Space Telescope and the Spitzer Space Telescope is both of those orbiting observatories where one orbits the sun

3:30and the other orbited, well, also the sun trailing behind the earth, is those two telescopes are working in infrared light. They are observing colors our eyes can't see. And so the teams associated with both observatories had to associate colors our eyes can see with, well, colors they can't. With the Spitzer Space Telescope, they use this extremely vibrant set of red and green and teal. And when you look at

4:07images from the Spitzer Space Telescope, it's often easy to go, oh, I know exactly what observatory produced that image because of the strong branding they used. This particular image, it's of, well, the Flower Bud Nebula, NGC 7129. And the way I came to learn this is this image was released on Valentine's Day and the big, beautiful red rosebud, that's a star-forming region. It glows with light

4:40that is reflecting around inside that rosebud. If you were to look at this with a visible light telescope, this would actually be blue, just like our sky is blue from all of that light that's reflecting around inside the cloud. That green stem, that is a nearby molecular cloud that is getting heated up, lit up, lit up from those nearby young stars, blasting it with light. And someday that cloud is going to form more stars. And it's really remarkable to me just how different the two teams

5:20interpreted this image. With Spitzer, as I said, we have that on-brand characteristic red and green and teal. And with JWST, we have colors that, well, it's two completely different teams. Spitzer is the Jet Propulsion Lab located at Caltech with IPAC, their infrared center. And with Webb, well, that's the Space Telescope Science Institute at Johns Hopkins University. And they're using much more of

5:53that current in-the-moment LED lights set of hot pinks, deep purples, golden hues that we see with both Hubble images and Webb images. In writing about this article, I found myself thinking that, yes, Shakespeare was right. A rose by any other name will smell as sweet. But apparently, if you completely change its color scheme, I'm not going to be able to recognize it. This pair of images really gives you a

6:29sense of what new science is possible with the larger mirror of the JWST that is capable of such higher resolution images. And also what happens when you have your secondary instrument suspended on a spider web of trusses that causes, well, bright spiky patterns all over your image. These are just two very different images. And to recognize a JWST image, you look for that characteristic set of eight spikes from how its

7:09mirrors are suspended and from the fact that it's using all of those multiple mirrors. This is just a cool image release. I don't have any real new science to add to this. Where we do start to get new science

White dwarf mass limits

7:26is in one of my favorite stories of the past few weeks. We learned that white dwarves aren't as limited in size as we might teach. Anyone who's had the fortune or misfortune, depending on your point of view, of taking quantum mechanics in university has probably been confronted by a homework problem where you're asked to carefully balance out what happens when a star's fusion turns off. It's no longer producing light that is

8:02pushing out against the force of gravity, which is trying to collapse the star. And in that, well, lack of light pressure, the star collapses until quantum mechanical forces take over. So as the story goes, when a star like our sun, basically, actually any star, eight solar masses or smaller, maybe a little bit bigger if it undergoes a lot of mass loss, when any of these stars run out of fusionable material in their core, when they can no longer burn

8:36hydrogen to helium, when they're no longer burning carbon, nitrogen, oxygen, when they run out of fuel, they're going to puff off their outer atmosphere, become a planetary nebula. And that ember left in the center is going to collapse down as far as it can until it reaches the point that the gas pressures in that ember of a former star push outwards and balance against gravity. Now, those gas pressures, normally when we think of

9:12gas pressures, we think of it as being dominated by, well, what's the temperature of the gas? What is the number of particles involved in the gas? All of these different factors from that Pervenert equation you may have learned in high school chemistry. In an object like a white dwarf star, however, that temperature relationship still matters, but the dominant factor is actually the electrons pressing against each other and living by

9:43the poly exclusion principle. According to the poly exclusion principle, any given shell in a group of electrons that are acting as a single population, normally this means all of the electrons in a single atom have to have a unique combination of energy and spin. So they have spin up, spin down. You can have two of them per energy shell in an atom. Now, in a white dwarf star, the star is going to keep collapsing down,

10:17keep collapsing down, keep collapsing down until the electrons have formed essentially a population that acts in a lot of ways like a single atom. With the electrons assuming the closest set of conditions that they can possibly have in terms of spin and energy. And this, the electrons pushing against each other is called electron degeneracy pressure. Now, the electron degeneracy pressure can only grow so big

10:53before the electrons just plain nope out, combine with the protons, form neutrons, release neutrinos, vast amount of energy goes out, and things tend to explode, which is not good if you want to be near that white dwarf. Now, luckily for us, our sun is unlikely to undergo this particular fate. It's too small to overwhelm itself when it collapses down after running out of fusionable material. And when you run those

11:30equations in that first semester of quantum mechanics class, what you learn is a core up to 1.44 times the mass of our sun is capable of pressing outwards with that electron degeneracy pressure against the force of gravity trying to crush inwards. Unfortunately, as soon as a white dwarf that is sitting in space, not spinning, not having magnetic fields, just sitting there, as soon as it exceeds that 1.44 solar mass,

12:04the electrons, that's where they nope out. And you get a type 1a supernova explosion. Now, the problem is, as we look out across the universe, we first of all recognize most stars are spinning, lots of stars have magnetic fields, there's other factors at play. And when we look at type 1a supernovae, we see that they aren't all actually absolutely identical. And based on how quickly they rise, how they fade away, we can see that they come in different varieties with slightly

12:38different masses, where some are what we call superluminous. They have 2.8 solar masses of material as near as we can match the data to, well, that pattern of behaviors that we know how to model. So the question is, how do you get from the, it explodes at 1.44 solar masses to, well, we actually see some that hold out and wait to explode to 2.8 solar masses. Well, this is where other forces come

13:11into play. So it turns out that once you set something rotating, inertia, that desire of things to keep going in a straight line causes oceans, gas, anything in the equatorial region of a round gravitationally bound together object to move outwards. Material, we see this on Earth, like our ocean, wants to go in a straight line, gravity is holding it to the Earth. As the planet rotates, it bulges at the center due to

13:48inertia creating a fictional force. We call it centrifugal force. The exact same thing happens in a white dwarf. And that extra fictional force, that centrifugal force, the inertia that is carrying stuff outwards, that allows the electrons to feel a little bit less pressure. That allows a little bit more mass to get piled onto the star. And it turns out with rotation, you can increase the total mass one of

14:21these stars is allowed to have. But that's not the only thing these stars are experiencing. If you further start to add magnetic fields, well, electrons have a magnetic moment. Everything in stars is basically charged and is going to interact in some way with a magnetic field. And that further allows additional material to get added on to that ember of a former star. And researchers trying to figure this out, led by,

14:56I'm going to mispronounce this, Zurn Zaruk, working in India, they were able to figure out that you can get one of these stars using spin and magnetic fields all the way up to 2.4 solar masses. And this is really cool for two different reasons. On one hand, it's amazing that we're starting to understand in detail how you grow a white dwarf from that maximum mass of 1.44 from that quantum mechanics

15:31homework set to the observed greater than two solar masses. But our modeling so far has only gotten up to 2.4 solar masses. It hasn't gotten all the way up to that observed 2.8, which means there's still things out there we don't understand, still things waiting to be discovered. And this is why scientists become scientists. We don't know everything. We want to know everything. And it is our pursuit of the answers to questions like, how do you get a white dwarf all the way up to 2.8 solar masses

16:08without exploding? How do you grow it that big? These are the kinds of things we live to figure out. And so this is that one-two punch of we're getting close to the solution, but there's still stuff waiting to be learned. And I am here for the things waiting to be learned.

True polar wander on Earth

16:33Now, there are times when I have to admit, because I'm an astronomer instead of a planetary scientist, the things that I'm apparently waiting to learn are really things I would have learned had I taken geology at any point in my life, which I have not. So I was reading through articles and I came across something that for reasons I can't explain, I found absolutely horrifying. And this is the knowledge

17:08that the surface of our planet is capable of just moving around free form as the magnetic field and rotating core of our planet maintain their current alignment. This is called true polar wonder. And the best way to explain it is if you take our planet as it is today and you pile a whole bunch of extra mass on, I'm going to pick on France because it's at a nice mid-latitude, or if you pile a whole bunch of mass on it, it's going to destabilize the rotation of our planet.

17:44Objects that are rotating want to have any excess mass they may have on their equator. So if you pile a bunch of mass on France, which is not on the equator, and it's also not on the pole, if you pile a whole bunch of mass directly on the pole, it's not entirely stable, but it's semi-stable. It's kind of okay. If you pile a whole bunch of extra mass on France, the outer layer of our planet is going to actually move until that extra mass you put on France is now on the equator.

18:18I knew this to a point. We've seen this when we look at other worlds that have massive craters and rings associated with them. So for instance, the asteroid Vesta has wrinkle ridges around its equator that were formed when it got hit by another asteroid that created a large crater and then sent ripples through the planet that created literally a ring of wrinkles around what at the time was not its

18:50equator, but what became its equator as it rotated to stabilize how its mass was distributed relative to its rotation. Somehow knowing that happens to other worlds and knowing it is currently happening to our own world are not the same thing in my brain. So when I learned that we are currently undergoing about 10 centimeters a year of the outside of our planet just going on walkabout, I found that a bit

19:25disturbing. Now we don't know if our world is currently undergoing true polar wonder where for millions of years the outer crust of our planet moves at several degrees per million years. But researchers are trying to understand how often in the past this has occurred. Yes, we are currently moving, but in order for it to be true polar wonder, it has to keep doing that for millions of years. We don't know if our world is going to keep doing

19:55what it's currently doing for millions of years. Now to understand when this has happened in the past, what one team of researchers did was they went looking to figure out when was it that the ocean's high tide was highest somewhere different than, well, where it had been at other times. In work led by Matthew Damier that appeared in the journal Science, they looked through the historic record, took into account how the plates on our planet are moving

20:32relative to relative to one another, measured historically where high tides have appeared and where they've moved to as our planet changed. And they were able to pull out four different times in the last 320 million years that the surface of our planet has undergone this true polar wonder. For those of you keeping track, these four epics appeared 20 to 30 million years ago during the Oligonkin period. I should have taken geology at some point. That was the period of time when

21:07the earth was covered with lots of grasslands and really big mammals. There is another epic of true polar wonder 90 to 100 million years ago during the late crustaceous. This was when ammonites, which are really cool fossils that many of you may have as jewelry. This was when they first appeared 140 to 150 million years ago at the boundary between the Jurassic and the crustaceous period, dinosaur period. There is another epic of true polar wonder. And then again, 190 to 200 million years ago during the early Jurassic, also dinosaurs, there is

21:43another period of true polar wonder. What triggers this? Why it happens when it does? These are all things that are still being figured out. What got me looking at this research was our world is punctuated by change. It's punctuated by periods where the continents have moved in different ways. Our world has been hit by asteroids at different times. We've had mass extinctions. And all of these different things have so many question

22:15marks attached to it. And we're still trying to figure out how they may and may not be associated with one another. And several of these periods of true polar wonder are associated in time with major extinction events. But that doesn't mean they are actually associated with major extinction events. Coincidence and causation aren't necessarily the same thing. And again, these are the questions I really

22:47want the answers to. And we just don't know. So what's interesting about this is their research on one hand was able to add credence to other research that had looked at magnetic field variation in rocks. There's places where as volcanoes have given off lava, as plates have divided, layer after layer of material has

23:17been produced and cooled and created a record of how the Earth's magnetic field has changed over time. And in looking at this paleomagnetism, we had a sense of different epochs of true polar wonder. There have also been other kinds of studies trying to understand when these things could have occurred. And this research was able to say, yes, these four, this is true polar wonder. But there was another event that I'm pretty sure is going to be debated for a long period of time that this particular study

23:53said, no, that wasn't true polar wonder. That didn't fit. And that was when the plates combined to create Pangea. And the entire planet, just like if you piled a whole bunch of matter on France, rotated. And they're saying that that didn't actually meet the criteria in terms of how the ocean tides locations changed for that to have been true polar wonder. But again, I think that's going to be one that we debate for time. Again, we do science for lots of reasons, and some of them is

24:29because the answer isn't crystal clear. And it's going to take some creative mind to figure out, okay, this is the evidence I need to say this is exactly what happened. But yeah, the Earth's surface is currently moving at 10 centimeters a year. Now, while I'm over here being horrified at something that in absolutely no way can harm me, our world has undergone some pretty dramatic events in its past.

Extreme debris disks and planet collisions

25:03Our world, for instance, three to four billion years ago, had a remarkable collision with a Mars-sized world that we have posthumously named Theia. And that particular collision led to the formation of the Earth's moon as material was splashed out. Now, we assumed because it happened to us, and probably happened to other places in our solar system, that these kinds of dramatic collisions must be common.

25:39As scientists, we tend to start from the premise that we are not in a special place, we are not in a special time. And if something has happened to us, it's probably common. But we may be wrong. And that's kind of awesome too. In looking out at other solar systems, first with the Spitzer Space Telescope working in the infrared, researchers went looking for hot dust surrounding stars. Hot dust is thought

26:15to come from all these kinds of collisions that can take place. We see lots of debris disks around stars. We see solar systems still in the process of forming, surrounded by dust and gas that's waiting to become planets. It's cooler. We see solar systems that are older that have debris disks in them that have either cooled off or just never formed planets. And they're cooler. In looking for what we call extreme debris disks, Spitzer first found a handful of stars with these disks. And it was far fewer than

26:54we had expected. And then JWST went looking, repeated some of those earlier observations, made additional observations. And at the end of the day, when all of these systems were observed, and a whole bunch of other systems that didn't have debris disks were thought about, it was realized these are far fewer than anyone had ever expected. So far, we have 21 systems that are well studied. And in looking at

27:27those 21 systems, researchers were able to break the research into two different kinds of extreme debris disks. In one kind, they found systems rich in silica materials. These are systems where they think that large worlds had violent collisions that just vaporized planets. These are collisions far more extreme than what our own Earth underwent when the Moon was formed. And so these systems with the silica-rich

28:03materials that they're finding. These are typically stars that are young, 300 million years or younger. And it's just amazing to think we are seeing evidence, first of all, that planets formed within the first 300 million years of a star existing. And second, of those worlds radically colliding and getting vaporized. This means when you look at star-forming regions that are young, think like Orion Nebula,

28:35you're potentially seeing worlds that have collided. Now, the other kind of systems that they found, they weren't silica-rich. Instead, they found things like quartz and foresight, which is a magnesium-rich material in the debris disk around stars. These other systems that they found, they had a whole variety of ages, which implies that these debris disks are capable of lasting much longer than the silica-rich materials. They also think that these materials came from collisions that were more glancing blows,

29:11those moon-sized objects smashing past each other, knocking surfaces off. Violence occurred, but it didn't vaporize planets. It's, again, one of these reflections that anything that can happen is going to happen somewhere out there among the stars. Per the European Space Agency press release about this research. The team proposes that the variability that they're seeing is driven by the

29:44rapid orbital and collisional evolution of fresh debris produced by multiple impacts. The research paper further discusses that the minerals observed in the disk may reflect the time since the collision, stating, after a giant collision, a new belt of resulting remnants, objects smaller than the original is expected to form. Subsequent collisions in the belt likely produced silica-poor materials,

30:14as these impacts are generally less energetic than the original, as typically found in impact simulations.

30:23We live on a world that once collided in a universe where worlds collide all the time, and we're now able to piece together the history of these collisions in systems spread across our galaxy using our space telescopes. It's a cool time to be doing science.

Closing notes and patron credits

30:48Now, I have gone through a whole bunch of different stories, rapid fire, and I want you to know all of this is written up in detail, and you can find my articles on all of these stories over on Escape Velocity Space News, evsn.tv. Another way that you can follow is join us over on Patreon, patreon.cosmoquest.org, where you will get not just these articles, but information on everything we're

31:21doing across all of our programs at CosmoQuest, including our citizen science, our periodic interviews, and everything else. Now, we are, as I said at the top of the show, in the middle of a bit of a period of chaos because I'm helping a friend who is ill and getting ready to do some travel, but we are here providing regular written content because I can do that from anywhere. So join us online, evsn.tv and patreon.cosmoquest.org. Our content is released early for paying members of our

32:01Patreon community, and then it's released for free, and everything we do is under creative comments. So share and use it however you can to help educate others. Thank you for being here, and thank you for sticking with us through this period of, well, we live in unusual times. Thank you, everyone. You go outside and look out. Bye-bye. Our programs at CosmoQuest would not be possible without all of our

32:32contributors at patreon.cosmoquest.org. We've updated our Patreon tiers, moving around some benefits to reflect the effort it takes our team to do things. Believe it or not, reading your names is one of the most stressful things I do because I really struggle with pronouncing things and feel bad when I screw up. Oh, and you can add pronunciation to your name in Patreon, and that does sort of help. Anyways, we have moved read your name to the $50 tier, meeting you once a year to the $20 tier,

33:06and adding your name to the end of videos to $10. Lower and higher tiers are unchanged. This month, we would like to thank Alan Gross, Ambius, Eric Lee, Greg Davis, Jeff Harris, Jill Holstein, Lenore Horner, Masa Herleu, Mike Els, Richard, Sandra Stanz, Stephen Veidt, Time Lord Iro, and Veronica Cure. Thank you all so very much. Escape Velocity Space News is executive produced and written by Dr. Pamela Gay. The This Week in

33:52Aerospace segment is written and researched by Eric Mattis and Dave Billard. Audio engineering is provided by Allie Pelfrey. Escape Velocity Space News is a production of the Planetary Science Institute, a 501c3 nonprofit dedicated to exploring our solar system and beyond. We are here thanks to the generous contributions of people like you. The best way you can support us is through patreon.com slash CosmoQuestX. Patreon benefits include exclusive access to ad-free podcasts, full-length guest interviews, weekly video chats with our production team, and other bonus content.

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34:33You are listening to the 365 Days of Astronomy podcast.

34:48Cool.

34:55The 365 Days of Astronomy podcast is produced by the Planetary Science Institute. Audio post-production is by me, Richard Drumm. Project management is by Aviva Yamani. And hosting is donated by Libsyn.com. This content is released under a Creative Commons Attribution non-commercial 4.0 international license. Please share what you love, but don't sell what's free. This show is made possible thanks to the generous donations of people like you. Please consider

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35:59and each milestone in space exploration, we come closer to understanding the cosmos and our place within it. Until next time, let the stars guide your curiosity. you

36:26you