transcript

Speaker 1:
[00:49] Astronomy Cast, episode 790, Meteorites from Other Worlds. Welcome to Astronomy Cast, our weekly facts-based journey through the cosmos, where we help you understand not only what we know, but how we know what we know. I'm Fraser Cain. I'm the publisher of Universe Today. With me as always is Dr. Pamela Gay, a senior scientist for the Planetary Science Institute and the director of CosmoQuest. Hello, Pamela.

Speaker 2:
[01:10] Hello, Fraser. I have a new favorite moment in rule breaking. Can I share it? Yes. Astronaut Commander Reed from the Artemis 2 integrity capsule was supposed to leave Rise, the little round plushie that they had as a zero-giat indicator. He was supposed to leave it on board integrity as it floated in the ocean, hopefully to be rescued, and he couldn't do it. He couldn't leave behind Rise, so he stole it.

Speaker 1:
[01:42] You don't leave a crew member behind.

Speaker 2:
[01:44] Right.

Speaker 1:
[01:45] Let's knock it out.

Speaker 2:
[01:46] Rise now is Commander Reed's, and he's been just carrying it around in lots of different. It is my favorite moment.

Speaker 1:
[01:54] Isn't it supposed to end up at a school though at some point? It's going to end up with some, I forget how-

Speaker 2:
[01:59] I don't know. I just know it wasn't left behind on the capsule, and there are so many adorable photos, and yeah.

Speaker 1:
[02:09] Man, that mission was so great. I was just transported to a younger version of me watching- The one that actually felt most significant to me was the Mars Pathfinder Sojourner mission. That was the one that I was really just glued to the live streams, watching every moment, and this brought me back to that world, watching all of these key moments, even just switching back to see the live stream, the quiet view of the port-hole of the Orion Capsule, to see either the moon or the earth. It was absolutely incredible, and it just shows us the best of what humanity can do. Obviously, there are details about the $4 billion that it cost to launch these things, the delays in the launch, the potential competition from reusable rocket companies and so on and so forth. But still, this was just humanity went farther than humanity has ever gone, and I was there for it, and it was incredible. I think we should do an episode about Artemis 2 when we have a little bandwidth. All right. Even though humanity has returned samples from a fraction of the worlds in the solar system, the cosmos has delivered many more without us having to lift a finger. Meteorites. We have meteorites from the moon, Vesta, and even Mars. What have we learned about these rocks from other worlds? And we'll talk about it in a second, but it's time for a break. Everyone deserves to be connected. T-Mobile and US. Cellular are joining forces. Our networks are coming together, bringing more T-Mobile coverage all over the country. Switch to T-Mobile and save up to 20% versus Verizon by getting built-in benefits they leave out. Check the math at tmobile.com/switch. And now T-Mobile is available in a US. Cellular store near you. Bigger network. The combination of T-Mobile's and US. Cellular's network footprints will enhance the T-Mobile network's coverage. Savings versus comparable Verizon plans plus the costs of options benefits. Plan features and taxes and fees vary. Savings with three plus lines include third free line free via monthly bill credits. Credit stop if you cancel any lines. Qualifying credit required. And we're back. Okay. Meteorites. Which worlds do we have meteorites from that have fallen down here on Earth?

Speaker 2:
[04:16] Mars, the moon, Vesta Ceres, a whole bunch of the other asteroids, but they come in families, which makes it a whole lot harder to say exactly which one they came from.

Speaker 1:
[04:31] Right. They came from this family. Who knows if it was which of the specific rocks.

Speaker 2:
[04:34] And I'm pretty sure we don't have any from Venus, but...

Speaker 1:
[04:38] No, we don't.

Speaker 2:
[04:39] Okay. You often prove me wrong, so I have learned to add caveats.

Speaker 1:
[04:45] That might be wise. Yeah. No. From what I understand, there are none from Mercury, none from Venus.

Speaker 2:
[04:52] The energy from Mercury is not realistic, and Venus' atmosphere is just like super thick.

Speaker 1:
[05:00] Yeah. Nothing's getting out of either of those. Yeah. Yeah. Okay. So, and that is incredible. So, how, like, how do they get here?

Speaker 2:
[05:09] Well, when a rock hits a rock, transfer of momentum is an expletive. So, what ends up happening, and this is part of my favorite caption that has ever existed in a print magazine. There is this amazing caption that I believe based on the formatting of the page, that I found on Reddit, came from Scientific American. I've not been able to find the actual article. The caption basically reads that when the asteroid that killed the dinosaurs struck earth, the shock wave flung at escape velocities, dirt, trees, and dinosaurs.

Speaker 1:
[05:57] What a way to go.

Speaker 2:
[05:58] Yeah, so the first life forms to leave the planet earth were very dead dinosaurs.

Speaker 1:
[06:04] Right.

Speaker 2:
[06:06] But...

Speaker 1:
[06:06] I mean, probably very dead...

Speaker 2:
[06:08] Many other things.

Speaker 1:
[06:10] Many other things, yeah. When you think about the giant impacts that have happened in the history of planet earth, there was some early first astronaut.

Speaker 2:
[06:18] So when space rot comes down, whether it be something tiny that just becomes a meteorite or something bigger where you just keep calling it an asteroid, when it collides, that kinetic energy from its motion ends up getting translated into heat, into noise, into compression waves moving through the ground, and that energy excavates the crater, melts a lot of stuff, flings boulders in all directions as it does its excavating. And some of those things that it flings are going to be going at escape velocities from whatever world is getting hit. And those excavated chunks of world are then on their own orbits that could include a trajectory that heads them straight towards us. And this leads to all sorts of mixing of early solar system substances back when collisions were much more common between the early forming worlds that, well, Venus, Earth and Mars were all settling in to habitability at about the same point before Mars decided to become too cold and Venus decided to become way too hot.

Speaker 1:
[07:46] So let's talk about some of the samples that have been found and some of the most interesting ones. And I mean, I think, I mean, this is not the same as a meteorite that is out in space. This is not the same as us retrieving a sample from an asteroid or from a comet. When you think about, say, Hayabusa, Hayabusa 2, Cypress Rex, they pulled a chunk, they pulled material off of these objects and these were in a pristine state. Obviously, they're rubble-pile asteroids. They've seen some things, but they haven't experienced the same kind of shock and damage that has happened from something that was actually scoured out of another planet.

Speaker 2:
[08:30] Yeah. We have three scientific problems with donated samples from other worlds.

Speaker 1:
[08:38] Right.

Speaker 2:
[08:38] Yeah. One is we don't know exactly where in that other world it came from.

Speaker 1:
[08:44] Hold on. I was going to bring that up, but actually, they're starting to get a sense of where some of the samples came from.

Speaker 2:
[08:50] For some worlds, but we can't consistently do it.

Speaker 1:
[08:52] The Mars ones, they're getting a sense based on the kind of... We know so much about the rock on Mars that we can guess where those samples might have come from, roughly.

Speaker 2:
[09:03] But we can't do the kinds of things that we do with collected lunar rocks where we take them into a lab, we measure exactly how old they are, and then we can use them to calibrate our understanding of how old different surfaces on the moon are. We can't do that.

Speaker 1:
[09:17] No. And think about what's happening with Perseverance as it is going across the landscape of Mars, looking for the perfect rock, and then drilling a sample, holding it closely inside its sample container, moving on. That is precision in what you get, as opposed to what you'll get with just random rocks being hurled at the planet.

Speaker 2:
[09:39] Right. Right.

Speaker 1:
[09:40] So that's the first challenge. You don't know where they came from.

Speaker 2:
[09:41] Right. So first challenge is you don't know where they came from. Second challenge is they're getting altered by the space environment a whole lot. So there was whatever excavated them was a high-energy event. They traveled through space, which causes surface weathering. And then they went through our atmosphere, which causes its own form of challenge as it gets heated up and then smashes into whatever it smashes into.

Speaker 1:
[10:11] Yeah. And that's probably not the worst part of the contamination. The worst part is that they then sit on the surface of the Earth for an unknown amount of time being infested by our local life forms. And one of these meteorites can be hidden for hundreds, thousands, tens of thousands, hundreds of thousands of years.

Speaker 2:
[10:38] Hundreds of thousands is pushing it because we do get them from places like deserts and ice flows. And our planet has had weather cycles.

Speaker 1:
[10:50] Right. But the point being that that's plenty of time for...

Speaker 2:
[10:54] Occupation to occur.

Speaker 1:
[10:56] Yeah. I mean, what probably happens is that the various weathering process that we have on the Earth dismantle the meteorites within that time frame. So it's the ones that, you know, we get to them before they're completely faded away. But still, we can do science. What kind of science can we do with these samples?

Speaker 2:
[11:17] So there's the straightforward, which is you take them into a lab, you cut them into very thin slices, and you study what is the stuff inside them? What is the components? And this is useful for two different reasons. One is we can also shine light at them and reflect the light off and match them to other worlds. This is actually how we figure out what meteorite came from where when it comes to the asteroids, is we know the asteroids really well in reflected sunlight. You take a space rock, take it into your lab, reflect sunlight, sunlight off of it, and see what it matches, and that's its parent body. And then, and then, because we don't have samples of Vesta, we don't have samples of Ceres, we don't have samples of like all but just the tiniest handful of asteroids. So then, then we take them apart and look at them to measure the various mineral structures, to measure the various how does all of this stuff come together, and then shred them completely in a mass spectrometer to get at the atom by atom understanding. And some of the thin cuts that they do through these, and then shine light through look like the most amazingly chaotic stained glass. So our solar system is out there creating chaotic stained glass and sending it our way.

Speaker 1:
[12:46] But I think one of the most exciting things is that there is gas trapped within these rocks.

Speaker 2:
[12:53] Yes, I have to admit that is one of the things I am weirdly just less interested in. But we have found both liquid and gas trapped inside the crystalline structure of various minerals. It turns out things like diamonds in particular are very good at holding stuff in their inclusions. So when we get particularly lucky, we're not looking for amber containing animals, we're looking for minerals containing gas, containing liquid, containing a moment in the history of another world.

Speaker 1:
[13:31] Yeah. Yeah. I mean, again, this is just incredible. We think about this, that a giant asteroid smashed into Mars, scoured out material, sent it into orbit. These rocks have been floating around in the solar system. And then some part, portion of them found their way to the Earth's atmosphere, enter the atmosphere, reached the ground. A scientist found it and then sliced it open. And there were bits, there were tiny bits of trapped Mars atmosphere in that meteorite that you can then use to study the atmosphere of Mars at the time that the space rock was hurled into space. We're going to talk about this some more, but it's time for another break. Everyone deserves to be connected. T-Mobile and US Cellular are joining forces. Our networks are coming together, bringing more T-Mobile coverage all over the country. Switch to T-Mobile and save up to 20 percent versus Verizon by getting built-in benefits they leave out. Check the math at tmobile.com/switch. Now, T-Mobile is available in a US Cellular store near you. Bigger network, the combination of T-Mobiles and US Cellular's network footprints will enhance the T-Mobile networks coverage. Savings versus comparable Verizon plans plus the costs of options benefits. Plan features and taxes and fees vary. Savings with three plus lines include third free line free via monthly bill credits. Credit stop if you cancel any lines. Qualifying credit required. We're back. What have we learned, do you think? About being able to study these samples from other worlds.

Speaker 2:
[14:53] One of the first things we've learned is what makes someone a scientist is when they find something cool, they report it. Because so many of the meteorites that have been found that weren't in Antarctica where we send groups of humans who have been trained to find meteorites to go find meteorites. A lot of the other ones that have been found are like someone's back pasture, someone's back fordage. So farmers are one of the great sources of meteorites. Yeah, all over the world people find meteorites and when we're lucky they report what they've found and they share and we get to go get samples. We have learned that there are a whole lot of unique rocks that allow us to look at things and go, this is actually a crater right here. Because when the impactor is big enough, it creates tectites, which are multi bits of the rock that was already there, that now become new rocks, and it creates these shocked rocks where you can actually look at them and see through, they're called shock cones, go figure, we're not exciting in how we name things. So there's all these local ways geology gets wrecked when big things hit, and it changes the landscape. There's this one really funny case of a winery in France that was creating meteorite wine, and they were claiming that their vineyard, which is in this cool circular indentation, was a meteorite crater and everyone was like, ha, ha, ha, and it turned out that some geologists who were traveling who, of course, went because it was funny were like, oh, oh, wait, this, this, this might be, this might be a crater. Yeah. And so they went back and it was actually a crater. And I'm super sad because you can't get this wine in the United States. And I really want a bottle. So folks in France, I really want a bottle of this wine.

Speaker 1:
[16:59] Of space wine.

Speaker 2:
[17:00] And so we have learned that we need to listen to the locals. We need to listen to their stories. We need to listen to like oral traditions are a great way to figure out where craters formed in the past at various points in history. And then when we pick up these rocks, we also learn to be slightly afraid because they could be carrying stuff from that point in time where life existed on other worlds than this.

Speaker 1:
[17:30] Right. And I think we need to talk about one of the most controversial rocks found from another planet, Allen Hills, but it's time for another break. Everyone deserves to be connected. T-Mobile and US. Cellular adjoining forces. Our networks are coming together, bringing more T-Mobile coverage all over the country. Switch to T-Mobile and save up to 20% versus Verizon by getting built-in benefits they leave out. Check the math at tmobile.com/switch. And now T-Mobile is available in a US. Cellular store near you. Bigger network, the combination of T-Mobiles and US. Cellular's network footprints will enhance the T-Mobile network's coverage. Savings versus comparable Verizon plans plus the costs of options benefits. Plan features and taxes and fees vary. Savings with three plus lines include third free line free via monthly bill credits. Credit stop if you cancel any lines. Qualifying credit required. And we're back. So this is going to be a moment that is kind of seared into everybody's memory. And this happened at roughly the same time that I was enthusiastic about watching the Mars Pathfinder mission complete its various operations. Shortly after that, we saw the announcement of life on Mars, thanks to the Al and Hills meteorite.

Speaker 2:
[18:34] Yeah. And back in 1984, this meteorite was found on Allen Hill in Antarctica. And it takes a while for them to get through all the different meteorites they find and do research on them. And this particular one, they found it, they sorted it. And then Roberta Scor, who is the lab manager at Johnson Space Center, she was the one who found it. And it was claimed to be the oldest Martian meteorite that had been found to be four billion years old. And when folks started studying it, one of the things that the research team did was they cut it, they gold-plated it, they put it through an electron scanning microscope. So the gold plating was to make the electron scanning microscope work better. And when they looked at the images that came out of the electron scanning microscope, they saw what looked like little tiny nanobacteria nodules that were similar to what had been studied at places like Yellowstone. And the claim was made that life had been found in the Allen Hills meteorite. Now this was super controversial for a number of different reasons. One was it turns out if you're not like the absolute nicest person on the entire planet, people are going to show more skepticism to your research. And when we were all going to see the talks on this, the person presenting whose name I'm not going to name would show the meteorite, would then show pictures of his grad students in skimpy clothes next to where they collected the nanobacteria from field sites. And that didn't sit well with many of us. And so there's that underline that just kind of went into how you looked at the research. And then there was the knowledge that if you screw up your gold plating, you get artifacts that look exactly what they were saying was nanobacteria. And then there's the fact that just sometimes minerals do stuff. And they haven't really allowed the experiment to be replicated. So you have this situation where no other means of exploration have been able to replicate what they found. Other work done on the same meteor didn't find indications of life. And there was just kind of this overall blech involved in the research. So, yeah, they might have found something, but until it gets found in a more credible way, and likely until it's presented by someone that doesn't leave all of us feeling slightly creepy, it's life hasn't been discovered.

Speaker 1:
[21:54] Yeah, and I mean, I think you got to sort of compare this to what happened with, say, the Hayabusa and the Osiris-Rex mission. You had these samples returned. They were sent out around the world to dozens of teams with some of the world's best labs, and they've been trickling back their information, confirming each other's discoveries, finding all these amino acids and all of this sort of measuring the amount of water in these samples, and determining a lot of really interesting things about the early history of the solar system. This is partly that when a rock from space lands on Earth, it is just one rock, and then it's up to the team who claims it to work on it, to sort of decide how the information is sort of parceled out, and that if you have a really bombastic discovery, it is tricky to then put yourself to that level of scrutiny, and yet that's what science demands. That's how science works, as opposed to this sort of top-down, hey, we've got all these samples, here you go everybody, get back to some of what you found, and then they're kind of double-checking each other. So it's, yeah, it's, unfortunately, I mean, we have a lot of examples of this. We have the Viking, we have the Allen Hills meteorite, we have the discovery of Phosphenium Venus, we have the detection of methane on Mars, we have Monta Lake, yeah, we have all these times where life was found, and yet it just didn't hold up to scrutiny, the wow signal, like it just, it goes on and on and on. The discovery of satellites in orbit around the earth before the first artificial satellites were launched, the...

Speaker 2:
[23:38] The Japanese UFO on an archeological thing, yeah.

Speaker 1:
[23:43] Boyajin's sort of dust ring, like it goes on and on and on. And it just shows that when the potential consequences of the discovery are big, then the level of rigor and the amount of sort of ego setting aside needs to be done is astronomical, and few are up to that task.

Speaker 2:
[24:08] You really need to have no clear alternative answers because Occam's razor is a thing. And when you can say, yeah, but if you gold-plated it not perfectly, that's exactly what it looks like. That is such an easy explanation for what they saw. And it's not like you can un-gold plate the meteorite.

Speaker 1:
[24:29] Right. Yeah. So let's talk about hypothetical meteorites. Could there be meteorites from Mercury, Venus, Phobos, Io here on Earth somewhere?

Speaker 2:
[24:45] Phobos, yes. That's easy. Io, I mean, it could happen, but it's going to take a whole lot. And the idea of something being big enough, having come off of Io, traveled this way, and made it through our atmosphere, my brain is going, but it's a gooey world. I mean, it's not all gooey, but that's where my brain went is. It's gooey. Yeah.

Speaker 1:
[25:14] It's covered in rock. You hit it with an asteroid, it's going to blow up rocky chunks into space. They're not going to remain lava.

Speaker 2:
[25:21] Yeah. You just have to hit it really, really hard because of Jupiter's gravity.

Speaker 1:
[25:27] Yeah. You have to escape Jupiter.

Speaker 2:
[25:29] Yeah. You have to escape Jupiter's gravity, which means that you have to somehow dig deep enough to get a whole lot of boulders sent out at a whole lot of velocity. Io is giant question mark of could it happen? Well, a lot of things can happen. But I put the probability on that one super low. Venus depends on when. So Venus hasn't always had the atmosphere it currently has. So if you hit it really, really hard when it didn't have that super thick atmosphere, but had already solidified and before it got its prior atmosphere flung off, yes. So it's always had an atmosphere, it just hasn't always had its current atmosphere.

Speaker 1:
[26:22] But it is tricky to climb up that gravitational well.

Speaker 2:
[26:25] But if you can fling dinosaurs at escape velocity off of the planet Earth.

Speaker 1:
[26:30] Yeah, but you not only have to fling them off of a world that is as much as-

Speaker 2:
[26:35] You have to escape the sun.

Speaker 1:
[26:37] Yeah, you have to escape the sun. That is the challenge. You have to get, you have to climb, but people always sort of imagine Venus in this sort of, or these worlds in this sort of perfect balance, and you just drift away from one to the other. But no, the sun is this giant gravitational well. It is at the bottom of this gravitational well. Mercury has partially climbed out of this gravitational well. Venus is a little better and Earth is a little higher. But to go from Venus up to Earth, it literally is up to you got to climb a mountain, and that is a challenge. Of course, it's also difficult to climb down the mountain. Both are challenges.

Speaker 2:
[27:14] And this is where you have to be looking for things that are on elliptical orbits that intersect both Venus' orbit and Earth's orbit, because that is easier to accomplish. And as always, your friendly reminder that it is far easier to yeet things out of the solar system than to yeet them into the sun.

Speaker 1:
[27:35] Right. What about an interstellar object?

Speaker 2:
[27:38] Oh, yeah. I'm sure we have interstellar objects on our world. Yeah. Yeah.

Speaker 1:
[27:43] There must be...

Speaker 2:
[27:44] We just don't have a reflection spectrum to match them to, so it's probably like unlabeled mystery rock.

Speaker 1:
[27:52] Right. But you can imagine someone doing, say, a, you know, doing a sample of it, you know, looking for the radioactive decay and then going, wait a minute, this sample is 8 billion years old, right? This rock is 8 billion years old. Like in theory, that it's never been found before. All of the meteorites ever been tested have always been exactly the same age, the age of the solar system. But out there somewhere, there is a meteorite that will, when you test it. Now, they've found pre-solar grains in meteorites that are older than the solar system.

Speaker 2:
[28:24] But those aren't grains.

Speaker 1:
[28:26] Grains, not full meteorites. And yet you think, you know, we have, we've seen three interstellar objects passing through the solar system.

Speaker 2:
[28:33] Models show there should be like six to 12 a year.

Speaker 1:
[28:38] Yeah. And there should be probably 10,000 plus just going through the solar system at any one time. And so at some point in the past, an interstellar object has struck the earth and it's there somewhere on the planet for the finding. Yeah. And then can you imagine what we could learn studying a rock that came from another planet in the galaxy?

Speaker 2:
[29:02] The frustration of not knowing its provenance is the great frustration. Yeah.

Speaker 1:
[29:07] Yeah. Yeah. Yeah. It's just like, you know, it's made of different stuff. I mean, it would still be made of the same kinds of material, but the ratios will be different. Slightly different ratios. Yeah. Yeah. And it's older.

Speaker 2:
[29:17] Right.

Speaker 1:
[29:17] Be like, oh, it formed 8 billion years ago. But we don't know where. Like, maybe you could look at the chemistry of stars out there and find one.

Speaker 2:
[29:27] We can't even find our own siblings. Because we orbit the center of the galaxy, I think, every 250 million years.

Speaker 1:
[29:35] Yeah. Yeah. Well, so a lot of potential siblings of the sun have been found.

Speaker 2:
[29:40] Right. But we can't prove it because we've scattered to the four directions, inward, outward, forward and back.

Speaker 1:
[29:51] Yeah. Yeah, but that'll be incredible. If there's some time, like people have proposed that the trajectories of certain meteorites coming in hit the atmosphere, that they were on an interstellar trajectory. There was a search by Avi Loeb and others to try and find a meteorite, but the results were inconclusive. So we are still waiting for that. Probably the best thing is to just chase down an interstellar object and sample it directly and bring a piece home. That will be the greatest accomplishment of humanity, I think, is to be able to chase down.

Speaker 2:
[30:25] And you just did a video on that.

Speaker 1:
[30:28] Have I?

Speaker 2:
[30:29] You just did a video on chasing down meteorites.

Speaker 1:
[30:31] Yes. Yeah. Yeah. Well, those are ones in the Earth's atmosphere. Okay.

Speaker 2:
[30:36] That's true. That's true. So the meteor, meteorite, meteoroid set of words, just put all of this into your heads. Meteoroids, asteroids, are space rocks still in space. Meteor is while they're going through the atmosphere. Meteorite is once you've picked them up because minerals end in IT. So these words are evil. I just call them space rocks.

Speaker 1:
[31:03] Yes. And people love to give you a hard time if you confuse them, don't get it perfectly right. But I think there's a lot of edge cases where you kind of wonder, you know, does a meteor hit the moon?

Speaker 2:
[31:18] A meteoroid hits the moon. Yes.

Speaker 1:
[31:21] What if it's a kilometer across?

Speaker 2:
[31:23] Then it's an asteroid.

Speaker 1:
[31:27] I think meteors can hit the moon. I think if they're on a collision course with the world, that that's when they become a meteor, in my opinion. But anyway, I think we've wrapped up this topic. We're now starting to rabbit hole. Thanks, Pamela.

Speaker 2:
[31:41] Thank you, Fraser. Thank you so much to all of you out there. Being able to continue doing science communications in this day and age where we're seeing NASA literally cancel the entire office of science communications, it is an honor and a pleasure. This week, I would like to thank our patrons over on patreon.com/astronomycast who allow us to have Rich, Ali and others, Aviva, making sure we don't sound terrible. This week, we are pleased to thank the following people whose names I shall now mangle. Our show wouldn't be here without the wonderful support of so many of you over on patreon.com/astronomycast. This week, I'm going to thank you the best way I have, which is by probably mispronouncing your name. Thank you so much to Antisor, Arctic Fox, Astrosets, Benjamin Mueller, Bob Zatsky, Boogie Net, Breznik, Brian Kilby, Cody Rose, Conrad Holling, Daniel Schecter, David, David Gates, David Green, Diane Philippon, G. Caleb Sexton, Galactic President, Scooper McScoopsalot, Glenn Phelps, Gold, Jared Heal, Janelle, Jason Kwong, Jeremy Kerwin, Jim Schooler, John M. Jordan Turner, Laura Kettleson, Lee Harborn, Lana Spencer, Marco Irassi, Matt Rucker, Michelle Purcell, Michelle Witchman, Nala, Nate Detweiler, Olga, Patricia Hope, Paul D. Disney, Randall, Richard Drumm, Robert Palazma, Sachi Takaba, Sandra Stantz, Sean Matz, Siggi Kemmler, Slug, TC Starboy, Thomas Gutzita, Tiffany Rogers, Timeroid, Iroh, Tricor, Tricia Nakini, and Vettelie. Thank you all so very much. And I'm so sorry for my failure to pronounce things.

Speaker 1:
[33:55] All right. Thanks everyone. We'll see you next week.

Speaker 2:
[33:57] Bye-bye everyone. Astronomy Cast is a joint product of Universe Today and the Planetary Science Institute. Astronomy Cast is released under a Creative Commons Attribution License. So love it, share it and remix it. But please credit it to our hosts, Fraser Cain and Dr. Pamela Gay. You can get more information on today's show topic on our website, astronomycast.com. This episode was brought to you thanks to our generous patrons on Patreon. If you want to help keep this show going, please consider joining our community at patreon.com/astronomycast. Not only do you help us pay our producers a fair wage, you will also get special access to content right in your inbox and invites to online events. We are so grateful to all of you who have joined our Patreon community already. Anyways, keep looking up. This has been Astronomy Cast.

Speaker 1:
[35:02] Everyone deserves to be connected. T-Mobile and US. Cellular are joining forces. Our networks are coming together, bringing more T-Mobile coverage all over the country. Switch to T-Mobile and save up to 20% versus Verizon by getting built-in benefits they leave out. Check the math at tmobile.com/switch. And now T-Mobile is available in a US. Cellular store near you. Bigger network, the combination of T-Mobile's and US. Cellular's network footprints will enhance the T-Mobile network's coverage. Savings versus comparable Verizon plans plus the costs of options benefits. Plan features and taxes and fees vary. Savings with three plus lines include third free line free via monthly bill credits. Credit stop if you cancel any lines. You will find credit required.