How do giant planets make diamond rain? Does it really, you know, rain? Where does diamond rain exist? I discuss these questions and more in today’s Ask a Spaceman!

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EPISODE TRANSCRIPTION (AUTO-GENERATED)

this episode of Ask Us Spaceman is brought to you by the good people at better help. That's better. Help dot com I I know a lot of you listen to this show as a form of therapy A as a way of, of escaping the world and and just going among the stars on this wonderful journey. Uh, I am a big advocate for therapy. I personally see a therapist, and you would be surprised if you don't currently see a therapist how much they can really help you Just navigate a difficult life just like you see a doctor to help you with physical conditions, you should see a therapist Better help dot com is a way to do that. That's convenient. Affordable. Uh, these are licensed professional counselors that you can connect to online a range of expertise worldwide. It really is an invaluable resource. Uh, as a listener, you can get 10% off your first month by visiting our sponsor at better help dot com slash spaceman.

You can join 1 million people who have taken charge of their mental health again. That's better. Help. HE LP dot com slash spaceman The ice giants don't get nearly enough air time. All the attention goes to Jupiter and Saturn. Big planet, Biggest planet Giant Red Storm. Cool. Oh, did you know there's a heck gun and and everybody forgets about and Neptune and heck, most people haven't even caught up on the lingo yet and still call them gas giants instead of ice giants. But OK, when it comes to that, it's a pretty stupid name. I'm sorry, I'm sorry, astronomers, but come on, you could have had a better name for this Was So when I say the word ice giant, probably the first thing that pops into your head is a mythical creature or a character from Lord of the Rings that OK, the second thing that might pop up It might be a giant world made of solid ice.

I hate to break it to you, but the ice giants of the solar system are neither of those. That's right. They're not mythical creatures and they're not giant balls of ice. It's weird. You see, astronomers, astronomers, astronomers, astronomers, astronomers are always perfectly happy to give something the absolute worst name possible in this case I is really means a collection of elements that vaporize pretty easily. They tend to be found in the universe either as solids or as gasses. They tend not to be found as as liquids. We're talking about things like water or methane and ammonia. And if you're asking, what do water and methane and ammonia have in common? The answer is nothing, excepted astronomers. But keep in mind, astronomers are the same people who call literally every element except hydrogen and helium metal. So they're not the greatest in when it comes to classification.

You can tell that they got AC in college chemistry just like I did. And and they just don't care. OK? And they they have zero chance. There's just you know what? You're a metal. I'm oxygen. No, you're a metal. I'm plutonian. You're a metal. I'm ammonia. You're an ice. What? No, I'm not. I'm ammonia. I'm No, you're an ice or I get over, I deal with it. We're gonna call you an ice, and we're gonna move on with our lives. Jupiter and Saturn are mostly made of hydrogen and helium, which are proper gasses and hence gas giant. But Urus and Neptune are mostly made of water, methane and ammonia, which are ices, and I'm trying not to roll my eyes when I say it. And hence they are called ice giants to be absolutely perfectly clear. Nowhere within the planet's Urus and Neptune. Will you find any ice of any form? You will also not find any mythical creatures. Well, we we don't know that part for sure.

But hold on a second for that I mean, these planets are huge. They're multiple times the mass of the earth. OK, the pressures and temperatures inside of them are intense. The water and the methane and the ammonia. They exist in exotic, super pressurized form, not as frozen chunks of ice. I mean, we think, Well, I'm pretty pretty confident about that one. But truth be told, we don't know a lot about the interiors of Uranus and Neptune. In the 19 eighties, we had the Voyager missions and Voyager two sailed by Ni and Neptune 1986 and 1989 respectively. And since then we've had well, nothing. We've had missions to the other giant planets, the gas giants who get all the attention. We have Galileo and Cassini and Juno. And they've spent. We've spent decades around the gas giants orbiting them. We've even dropped a lander on Titan. But the only close up pictures we have of Yanis and Neptune are older than most human beings alive today.

They might be older than you. That was the last time we had a close up image of these worlds, and it's been over three decades. Seriously, think about that. Two out of the eight planets in the solar system, 25% of the planets in the solar system have not had a close up probe or orbiter. In three decades since we've been doing orbiters and probes and flybys in Landers, seriously. So my main point here, other than to to wine, is to talk about the fact that we really don't have a lot of information on these planets. We have the close up data. I mean, OK, well, here's here's Here's the basic problem. What I'm about to talk to you today about is diamond rain. Diamond Rain is something that happens in the interiors of Uranus and Neptune, but we don't know a lot about the interiors of Uranus and Neptune. What we are trying to do with the interiors of these worlds involves a lot of swags, SWAGS swags, which stands for Scientific Wild.

Um, guess it's not the greatest thing to just guess about this kind of stuff. But when it comes to the ice giants, which do not get a lot of attention, and I hope I've made my point perfectly clear, it's pretty much the only thing we have are a whole bunch of swags, because what do we have to work with? Well, we have, uh, we have the close up data taken by the Voyagers 30 years ago. Ancient history. By now we have Hubble and other ground based telescopes taking pictures and infrared observations, which are good at measuring heat. But from billions of miles away, the other side of the solar system we have laboratory experiments that try to recreate what's happening to various elements at high pressures and temperatures, like what we suspect is in the interiors of Uranus and Neptune. And lastly, we have our knowledge of science. We have math. We have a logic. We have reason. We have argumentation and evidence, and we we put this all together and you get diamond rain.

And here's the gist. It was first suggested way back in 1981 actually, even before the Voyager mission, Here's the deal. Uranus and Neptune probably have three general layers. Obviously, it's gonna be a lot more complicated than this in real life. But guess what? We don't have a lot of data. I can I Can I make this point any further? Yes, I can, and I will. We don't have any more data. And so we have to go with the simple models of the interiors the model suggests again, based on the observations we do have of the exterior of the surface of laboratory experiments, trying to replicate how ammonia water behave at high temperatures and pressures, and then just mathematical models that try to make sense of all of it that try to piece together all the despard information that we have. The models say that there are probably three layers and in a rocky zone which will not play a major role in this story in middle icy mantle. But but But by IC I mean, it's full of water and ammonia and methane, not icy.

It's not a giant slushy here, as we talked about, but I have to call them, I guess, because that's what the astronomers decided to call it. And I guess we put them in charge for some reason and then beyond the middle icy mantle is an outer, gassy envelope we can guess again, using our knowledge of science that the inner layer of the mantle, the part that is right up against the core, has a temperature of somewhere around 7000 Kelvin in a pressure around 6 million times that of the air pressure on the earth. See, I told you, no slushy for you here. There's no ices in ice form. There's only ices in weird quantum mechanical super pressure I form. It's a very expensive slushy, according to those same models, again, based on how big the worlds are, what the the outer atmosphere. Temperatures are like how these molecules behave. We can guess at what is going on on the inside. We think the outer layer of the mantle is much cooler only 2000 Kelvin and way less pressure only 200,000 times that of the earth.

That's a big difference, though That's a big difference, because at the outer layer you have a 200,000 times, the air pressure of the earth and then the inner layer. It's 6 million at the outer layer. It's 2000 kelvin at the inner layer. It's 7000 kelvin. Those are interesting differences, and we're going to exploit those differences to do some really cool things again. This is all through modeling. This is all swags, folks. Scientific wild guesses. We know that Uranus and Tune are giant balls. We know that they're held together by gravity. We know what it's like on the outside. We know what they're made of, and then we can model the interior to fit all the known facts. These models are definitely incomplete and probably wrong, but it's all we have to go on until we send another mission out there. So the fair question fair question What happens to water methane ammonia when it's subjected to these kinds of pressures and temperatures? How do we answer this question? Well, we have modeling like we did in 1981 and we guess that maybe something like diamond rain forms.

We also have laboratory experiments and to recreate those kinds of temperatures and pressures in a laboratory. We have science lasers. This is not a little laser that's a toy. Or you use to, uh, amuse your cat. No, these are science lasers. These are mega lasers. These are lasers that we shoot at things and for a brief fraction of a second, there is so much energy deposited on the target by the laser that the temperatures and the pressures can skyrocket. So you use a homemade like a homemade laser. You use a little handheld laser to play with your cat. You use a science laser to investigate what happens to your cat when it is subjected to a temperature of thousands of Kelvin. The answer is it. I don't think your cat is going to enjoy it as much as the little toy laser, the most recent experiment trying to understand what happens to these kinds of molecules and elements at these high temperatures and pressures that didn't use methane directly.

Instead, they use polystyrene it it's a plastic, and they used it because it's easier to play with than methane. Methane's a gas. It's really volatile. It it's just really annoying to to get it to hold still so you can shoot a science laser at it. But polystyrene has has all the same stuff, just more of it in different arrangements. So it's basically the same thing, and and and and you're saying like Paul like, That's not good enough. I'm sorry, OK? It's what we have methane, and we're especially interested in the methane and Uranus and Neptune is made of carbon and oxygen. It's some carbon with some hanger hangers on hydrogen, some groupies under intense pressures. We understand this both through mathematical calculation, our knowledge of science and through the use of science lasers. Under intense, intense pressures, the Hirogen rips off, leaving a bunch of carbon atoms with nothing better to do and because of the insane pressures. All those carbon atoms with nothing better to do get together and they form crystalline structures. This is exactly what carbon atoms do in the mantle of the Earth, but they take a lot longer to do this in the mantle of the earth.

And what do crystalline structures of carbon do they contribute to Patreon? That's patreon dot com slash PM Sutter. Only under the highest pressure and temperature conditions do crystalline structures of carbon directly support this show, and I thank them for that. But they make diamonds. That's what they do. That's the whole show. The title of the show is Diamond, Right? So you knew where I was going with this now. In the experiments, when they shot a science laser at a polystyrene target, which has a lot of carbon and a lot of hydrogen, the hydrogen blew off the carbon made diamonds. These diamonds were only like a nanometer across, in other words, small. But that's because we have a tough time maintaining those kinds of pressures and temperatures for very long. Because of the enormous energies required to power science lasers, we just couldn't do it. So we have a fraction of a second. We attain those kinds of temperatures and pressures with our science lasers, and then we see what happens to carbon and hydrogen.

It turns into little tiny diamonds that are super small, it's thought, and it's reasonable to say it is a swag here. But hey, it's a reasonable swag. It's thought that if methane had more time under these kinds of temperatures and pressures, it would grow larger crystals. In other words, actual diamonds that you would care about. Maybe they might still be microscopic, but they'd be They'd be big, all right? They wouldn't be a nanometer across. So we think that at the upper layer of the mantle in Uranus and Neptune, the pressures and temperatures are just right to shove a part of the methane break off the hydrogen. Then the hydrogen goes off and does something we don't really care about them. All those carbon atoms squeeze together because they have nothing better to do. They grow diamonds just like the mantle of the earth grows diamonds out of a bunch of leftover carbon. And what do these solid diamonds do? They fall because now they're dense. They're heavy. They're not just random atoms floating around doing nothing.

They now have purpose. They are denser than the surrounding medium. Remember, there's all the also a bunch of water and a bunch of ammonia. Who knows what kind of funky things they're doing. But we're gonna ignore them for now, and and they're probably in some super quantum fluid state anyway. But the carbon breaks apart and the carbon glues together. And then it falls as diamond rain and they fall through the mantle thousands of kilometers. They fall, fall fall, fall, fall. And remember, the inner edge of the mantle is much hotter and much more dense and pressurized than the outer layer of the mantle. And eventually it gets so hot, so intense, so dense that the diamonds can't survive anymore. They get smashed, the diamonds break back up into their constituent carbon atoms. And then what do the carbon atoms do? Well, they circulate around, they hang out. They're now at the bottom, but presumably again, swag territory here. But this is what we got. Presumably, there's some sort of convection currents happening inside of Uranus and Neptune, just like it happens in the mantle of the Earth.

You've got a super hot core and a not so hot surface. And so there's differences in heat and differences in heat cause material to cycle up and down. So you have these great plumes of water at A and methane. I reach your, uh being heated near the core, then rising to the surface and then cooling off and then slinking back down to the inner portions of the mantle and back and forth, back and forth. So you get this circulation of carbon, you have the carbon rain, the diamond rain precipitating, raining down to the lower manual manual mantle. And then you have the loose carbon atoms getting circulated back up, and then the process repeats again and again. It's just like the water cycle on the earth. Your water vapor becomes a liquid. The raindrops fall. Eventually they evaporate and make their way back up. It's a full water cycle of precipitation and evaporation. We have a diamond cycle on Uranus and Neptune. Carbon atoms are raining down from the upper layers of the mantle and vapor evaporating and in the lower levels of the mantle and circulating back up.

This is likely not happening in the gas giants. It might be happening in the gas giants, but likely not. Why? Because they're gas giants and not ice giants. They don't have enough methane to make this work, and they don't have enough methane at the right temperatures and pressures to trigger the formation of diamond rain. It might be possible there are some papers exploring that, but it's much more likely happening in Uranus and Neptune before I continue. I want to let you know that this show is brought to you by the wonderful folks at brilliant dot org. Brilliant is an online stem learning platform, and it really is hands on, which is the best way to learn. That's how I learned in undergrad, and it's It's just so much fun. I love their style. I love the way they approach things. They have two courses in particular that I think you would absolutely love. There's one on special relativity and one on gravitational physics. And how many times in this show do I say that? Really? I'm just translating the mathematics for you because math doesn't really work out so well in a podcast.

And I know a lot of you want to dig deeper without actually enrolling in a university course, which would be somewhat cumbersome. And this is the perfect place to fill that gap, where you can dig deeper in an interactive, fun, engaging way and and learn some cool stuff about the universe. Head over to brilliant dot org slash spaceman to get started with a free trial and get 20% off in annual membership. That's brilliant dot org slash spaceman for 20% off unlimited access to all the awesome course is on brilliant for a whole year. So some questions. Diamond, rain, Paul, Uranus, Neptune Ice giants. What's going on? How big are the diamonds? We don't know how much of the car ban gets converted into diamond rain. We don't know. Does this even really happen? We don't know. Like I said, this is swag territory here. Scientific wild guesses. We have very limited data about Uranus and Neptune. We have extremely limited data about the interiors of these worlds.

We are doing our best here. But hey, how cool is it that our best came up with something like Diamond Rain? It's plausible. No, we don't know for sure if diamond rain is possible. Yes, it sounds super cool. It is also plausible. It matches up with everything we know about the plants, which is not a lot, but it matches up with everything we do know about Uranus and Neptune. It seems to be validated by laboratory experiment in science lasers. It's a likely scenario based on all the available evidence. And you've heard me talking before on the show about how all of science employs models and data fitting and trying to take the known observations and make predictions This is an example of it. We're taking the known data about what we have on these worlds, and we're turning it into diamond rain. That said, there are a lot of mysteries when it comes to Uranus and Neptune. We do not fully understand the interior structures, and we don't understand the interior structures of Jupiter and Saturn.

But at least we have a lot more data to go on. When it comes to those worlds and we have more sophisticated models, we have better understanding. Uranus and Neptune are just like, yeah, they've got insides, that's about it. So we don't fully understand the interior structures, the relationships between the core, the mantle and the outer envelope. We don't understand the dynamics fully of the the the interiors of these worlds, of how heat is transported of, of winds, of of pressure changes. We don't know how efficiently heat goes from one place to another. Whe When you look at Uranus and Neptune, they look so boring. I'm sorry, Uranus and Neptune, but they really do. Saturn looks boring, too, but it has rings to compensate for that. Jupiter is just very interesting with all those cloud bands. Uranus and Neptune just look boring. But we look closely with with the that we do have and we do see storms. We do see bands. There are very, very interesting atmospherics happening there.

But we don't know how heat. Oh, you know, all weather in the solar system is driven by unequal heat. That's how we get our weather here on the earth. That's how Jupiter gets its weather. And that's presumably how Uranus and Neptune get their weather. But we don't fully understand that. Uh, there there are magnetic fields involved with these planets. Uranus has a super weird magnetic field, so I've been lined up anywhere close to the axis of rotation of the planet. I mean, U. Uranus itself is knocked over by 90 degrees. We we don't fully understand the magnetic field. There's also this giant mystery of why is Uranus colder than Neptune? In fact, Uranus is the coldest planet in the solar system. It is. It's emitting the least amount of heat. Super weird. Why? We don't know. And why? If Rini and Neptune are pretty much the same, they're both water. They're both ammonia. They're both methane, roughly the same ingredients, roughly the same mixture, but one is much hotter than the other. We don't fully understand the diamond rain may play a role in all of these.

Just like the water cycle on the Earth plays an important role. The water on the earth plays a role in our weather. The water on our on our Earth plays a role in erosion. The water on our Earth even plays a role in plate tectonics. It lubricates plate tectonics. Water is a part of what makes the Earth the earth. Diamond. Rain may play a role in what makes Uranus and Neptune, Uranus and Neptune. They may play a role in transporting heat. They may play a role in driving the magnetic field. They may play a role in governing the the appearance of storms in the atmosphere. We don't know, though we don't know how significant this diamond rain is. We don't know what roles it might play. We don't even know if it really exists. But, hey, the concept of diamond rain is super cool. Our universe is so weird, isn't it? Our universe is so weird. Who would have thought if you went and talked to some ancient astronomer who's charting sunsets and sun rises and eclipses and notable stars.

If you said Hey, so sit down for this. You see, they didn't even know about Uranus and Neptune in the first place. You can see it. It is possible, by the way, to see Uranus with the naked eye. But you don't. It's really, really tough to recognize as a planet. You would say, Hey, OK, you know the planets Mercury, Venus, Jupiter, Mars Moon Sun. OK, there's a couple more. We called them er and Neptune. They're they're pretty far away. They're very big. They don't look anything like the Earth. And if you were to plunge inside of it, diamond rain, a literal rain of diamonds would fall from the sky. What a wonderful thing. What a wonderful thing to talk about. What a wonderful thing to be able to say. All based on our on our limited observations are one flyby and some science lasers. So maybe the more we talk about Diamond Rain, the more attention the ice giants will get. Who knows? I might even devote an entire episode just to the ice giants, But first you need to ask, Thank you so much.

to kill zone red Nike on Twitter for the question that led to today's episode, and the question was literally, What's up with Diamond Rain? I'd like to thank my top patreon contributors and all my patreon contributors. I really do appreciate all the support you give me and of the show. It really does mean a lot but my top ones. This month, the top contributors were Justin G, Chris L Barbeque Duncan M, Corey D, Justin Z, Nate H, Andrew F, NAIA Aaron Scott M, Rob H, Lowell D, Justin Lewis, M, Paul G and John W. Go to patreon dot com slash PM Sutter So you can keep the show going. And, hey, let's all enjoy some diamond rain every once in a while, you know, get some bling on this and I will see you next time for more complete knowledge of time and space.

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