Listener Questions #24

Daniel and Kelly answer questions about Jupiter and circadian rhythms. See omnystudio.com/listener https://omnystudio.com/listener for privacy information.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Daniel Whiteson?

  This is an iHeart Podcast. Guaranteed Human.

• 0:04Speaker 01

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• 0:34Kelly Weinersmith?

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• 1:11Daniel Whiteson?

  If the Earth and Jupiter were to collide, what would happen? How would we die?

• 1:17Kelly Weinersmith?

  Circadian rhythms are corrected using the sun's light. If you live at the bottom of the sea, how do you get that right?

• 1:24Daniel Whiteson?

  How big a planet could we use rockets to escape? If we'd evolved on Jupiter, would we be planet-bound apes?

• 1:32Kelly Weinersmith?

  Whatever questions keep you up at night, Daniel and Kelly's answers will make it right.

• 1:37Daniel Whiteson?

  Welcome to Daniel and Kelly's Extraordinary Universe.

• 1:41Kelly Weinersmith?

  With an emphasis on Jupiter, it seems.

• 1:56Kelly Weinersmith?

  Hello, I'm Kelly Wiener-Smith and I study parasites and space. And clearly Jupiter is the best planet.

• 2:04Daniel Whiteson?

  Hi, I'm Daniel. I'm a particle physicist and yes, Jupiter has the most particles of any planet.

• 2:10Kelly Weinersmith?

  And does that make it the best as a particle physicist?

• 2:14Daniel Whiteson?

  It makes it the mostiest, I guess. You know, I think people underestimate like how much of the solar system is just the sun and Jupiter. Like mostly it's just the sun. And then you want to add Jupiter, all right, to round it up to 99.9 and everything else is just details. We're really just here in somebody else's party.

• 2:32Kelly Weinersmith?

  Oh, man, that's a little, it's a kind of a bummer of a way to start our episode.

• 2:38Daniel Whiteson?

  We are all insignificant. No, I think it tells you something, though, when you look at the depiction of the solar system and all the planets are like big. And obviously it's not to scale, but it tells you something about what we find important, right? Clearly we are important in the solar system, so we zoom up. It's like that cover of the New Yorker where they show like a map of the United States from the New York City perspective and it's like mostly Manhattan and then like a few details. And that's ridiculous and you laugh at it, but that's exactly what we're doing about the planets. Right?

• 3:09Kelly Weinersmith?

  Well, but you know, I, on the one hand, we've, we've known about Jupiter for much less long than we've known about Earth and you know, we're here on Earth, makes it easier to study. I'm gonna go ahead and, and stand down on defense of Earth and, and the Earth centered view of the world.

• 3:25Daniel Whiteson?

  I'm not saying it's wrong. I'm just saying it reveals something about our biases, right? The things we think should be presented first.

• 3:31Kelly Weinersmith?

  I grant you that, but, but there's probably, you know, solar systems that are bigger than ours and maybe we shouldn't even be talking about our solar system at all. And where do you stop, Daniel? Where does it end?

• 3:41Daniel Whiteson?

  It never ends, Kelly.

• 3:45Daniel Whiteson?

  There's no bottom to the philosophical rabbit hole.

• 3:47Kelly Weinersmith?

  Oh, my goodness.

• 3:48Daniel Whiteson?

  But we love going down rabbit holes, especially rabbit holes that you are interested in. So if you have a question about the nature of the universe, or how something works, or how little squishy critters make their lives, please write to us with your question. We would love to answer it here on the pod. And today we're answering three super fun questions from listeners.

• 4:07Kelly Weinersmith?

  That's right. So let's start with our first question from Brad.

• 4:10Daniel Whiteson?

  A great question about Jupiter, of course.

• 4:13Speaker 03

  Hello, Daniel and Kelly. I have a question about planetary collisions. Jupiter is classified as a gas giant planet and is known to sweep up many stray masses flowing through our solar system. If something were to happen to cause Earth and Jupiter to collide, what would happen at impact? Is the mass of Jupiter large enough to spaghettify Earth and destroy us like a black hole? Or is the likelihood of a direct collision too small and Earth would just be ejected from the solar system if we become too close? Or is the surface of Jupiter really a gas and Earth would just pass into the inside of Jupiter and basically be absorbed and Earth would just coast through a dense atmosphere of gases and would eventually hit a solid core? Thanks, Brad from League City, Texas.

• 4:53Daniel Whiteson?

  So Kelly, do you think Brad is a supervillain planning to push Earth into Jupiter or threaten to?

• 4:58Kelly Weinersmith?

  You know, I did wonder about that when I was listening to this question. I'm a little concerned and you know, one, I'm a little concerned in general now that this is something, you know, on my radar to worry about. And then two, I'm a little worried about Brad in particular.

• 5:12Daniel Whiteson?

  A couple of red flags here. Yeah.

• 5:14Kelly Weinersmith?

  Yeah, that's right.

• 5:14Daniel Whiteson?

  I'm not sure in his question if he's worried about this or excited about it. He's like, hmm, let's do the experiment.

• 5:20Kelly Weinersmith?

  Yeah, yeah. Hard to say, hard to say. Maybe we shouldn't give him the answer.

• 5:25Daniel Whiteson?

  Exactly. I worry about that. Like when the kid wrote to me and asked me what it would take to blow up Mars. I was like, hmm, should I really be telling a 10 year old how to destroy a planet?

• 5:35Kelly Weinersmith?

  But on the other hand, you know, you, you hope they don't wield that sort of power to do anything about the information.

• 5:40Daniel Whiteson?

  Who knows what today's 10 year olds will do in 20 or 30 years, right?

• 5:45Kelly Weinersmith?

  That's true. That's true. And you'll be to blame, Daniel.

• 5:48Daniel Whiteson?

  I accept that blame. But today, we're here to answer Brad's question as a hypothetical science question about something we hope will never happen, which does reveal a lot of really interesting solar system physics. So let's get into it.

• 6:01Kelly Weinersmith?

  And I think we should probably start with what is spaghettification? Because that is, you know, clearly one of the best scientific terms our community has ever come up with.

• 6:10Daniel Whiteson?

  Absolutely. Spaghettification is usually used to describe what happens to an object as it approaches a black hole, in that you won't just fall in, you'll be torn apart into spaghetti, essentially, before you actually fall into the black hole. And this doesn't just happen around black holes. It happens all the time in strong gravitational environments. In fact, it's happening to you right now, and it's happening to the moon. It's the result of tidal forces. And the reason simply is that the force of gravity depends on distance. So if you're falling into a black hole, or you're orbiting a planet or whatever, and your feet are closer than your head, then your feet have a stronger gravitational force on them than your head does. And effectively, that's a force pulling your feet away from your head.

• 6:53Daniel Whiteson?

  And if that force is strong enough, it will pull your head off your body, or your feet off of your head, depending on your perspective.

• 6:59Kelly Weinersmith?

  I'm gonna be honest here. I feel like you've sort of de-excitified spaghettification for me by being like, it's just a kind of tidal force. It's like, what's happening to the moon? I'm like, oh, but spaghettification, that's not what I imagined in my head.

• 7:12Daniel Whiteson?

  Oh, you were imagining some sort of black hole magic?

• 7:15Kelly Weinersmith?

  Yes, yes, I thought this was a specific black hole-y thing. And that spaghettification really, you know, required you to be thin like a noodle. But, okay, all right.

• 7:24Daniel Whiteson?

  Physics has been ruining things since 1584, or whatever.

• 7:27Kelly Weinersmith?

  Oh, and what happened in particular in 1584, Daniel?

• 7:31Daniel Whiteson?

  I just made a did I was referencing one of Zach's comics.

• 7:35Kelly Weinersmith?

  I can't remember what year he had on that, or why he picked it.

• 7:40Daniel Whiteson?

  I think it was supposed to be like Galileo's experiments or Bacon or somebody like that. Anyway, the point is that tidal forces are a thing. So if you approach Jupiter, for example, then the difference in forces between one side of your object and the other side of your object, those are the tidal forces. And that's why we have tides on the earth because the moon pulls on one side of the earth more strongly than on the other side of the earth, making it a little bit of a football. And the earth is the same thing to the moon. And that's why the moon is locked in place. It's called tidally locked because it's a little bit of a football and it's hard for it to spin away from having the pointy bit of its football aligned with the pointy bit of the earth's football.

• 8:17Kelly Weinersmith?

  Okay, but so Jupiter is much bigger than the moon. So is, you know, you, you said that when the force gets hard, it could like pop a head off. Is earth's metaphorical head gonna pop off towards Jupiter? Or is it just gonna get like weird tides?

• 8:31Daniel Whiteson?

  Yeah. So there's a boundary called the Roche limit. If you get closer than that, you get torn into pieces. If you're further away from that, you don't. And that's why some planets have rings and some planets have moons. If your moon is further away than the Roche limit, it stays together. Local gravity wins over the tidal forces. If you get too close, then it gets torn apart into a ring because the tidal forces overcome the internal gravity. So that's the Roche limit. So what happens as the earth approaches Jupiter? Well, the Roche limit for a solid body like the earth is actually inside the cloud tops of Jupiter. Jupiter is a gas giant and the outer layer is like 50 kilometers of just clouds below which you have like gaseous hydrogen and then

• 9:11Daniel Whiteson?

  liquid hydrogen and then this crazy helium neon rain and then an ocean of metallic hydrogen before you get to the icy rocky core. So the earth would sink into the clouds without getting torn apart. It would get torn apart after it already passes into the clouds.

• 9:29Kelly Weinersmith?

  Okay. So at that point, we are closer to Jupiter than Jupiter's rings, right? So earth's not going to become like a ring of Jupiter. It's going to get torn apart and then rain down on Jupiter. Is Jupiter the planet that has the diamond rain?

• 9:43Daniel Whiteson?

  I think that's Saturn.

• 9:44Kelly Weinersmith?

  Ah, alright.

• 9:46Daniel Whiteson?

  He's so disappointing. Jupiter yawn.

• 9:49Kelly Weinersmith?

  Come on Jupiter. Step up your game, man.

• 9:53Daniel Whiteson?

  All right. So now we have a collision of an entire Earth, right? It's whole. It has not been pulled apart by the tidal forces of Jupiter. And it hits Jupiter and Brad asks like, what's going to happen? Is it going to pass in and be absorbed to hit the solid core? And you're definitely not going to make it all the way to the solid core. Because even though Jupiter is a gas giant and has like layers and layers of hydrogen, that hydrogen is dense and atmospheres have friction. Even here on Earth where atmosphere is pretty low density compared to the Jovian atmosphere. You know, there's reentry. If a rocket or an asteroid tries to enter the Earth's atmosphere, there's a lot of friction from the atmosphere and you get all this heat. And most things that hit the Earth's atmosphere don't make it to the surface.

• 10:36Daniel Whiteson?

  Same principle applies when the Earth hits the Jovian atmosphere.

• 10:39Kelly Weinersmith?

  Okay.

• 10:40Daniel Whiteson?

  And so what's going to happen is you're going to compress the Jovian atmosphere, which is going to heat it up, turn it into plasma, and that's going to vaporize the crust and the mantle of the Earth.

• 10:49Kelly Weinersmith?

  Shoot.

• 10:50Daniel Whiteson?

  Yeah, bad. And so essentially a massive energy release here. Did a little bit of the back of the envelope calculation. And assuming that the Earth hits at like 60 kilometers per second, which is, you know, fast, but not super fast for solar system speeds. You're going to release 10 to the 18 megatons of TNT.

• 11:10Kelly Weinersmith?

  Oh, wow.

• 11:10Daniel Whiteson?

  And you might be like, I don't know what that number means. Well, the Hiroshima explosion was 15 kilotons. This is 10 to the 18 megatons. So it's like so much bigger. And, you know, I mean, the entire Earth is essentially a bomb. And a lot of that mass is converted into energy. So it's an enormous explosion. You're going to get like a fireball rising above the surface of Jupiter. It's going to be much bigger than the volume of the Earth. And you're going to have shock waves in the Jovian atmosphere, which probably will last for years.

• 11:41Kelly Weinersmith?

  Wow.

• 11:41Daniel Whiteson?

  You may even leave a spot on Jupiter. It's very unlikely you're going to make it all the way to the core because you've got lots of dense layers before you get there. But yeah, it's going to be a huge impact. But remember Jupiter is huge compared to the Earth. Like it's so much bigger than the Earth. That even though this is an enormous amount of energy and would devastate the Earth, vaporize essentially Jupiter's. Going to mostly shrug it off.

• 12:04Kelly Weinersmith?

  Oh, man, that's a little insulting. Every human I've ever known or loved disappears and Jupiter's like meh. Okay, well, so so say at this point, when this happens, we have a self sustaining settlement on Mars. If the Martians were like in the right position, could they see this? Or would the act of Jupiter moving towards Earth have destroyed Mars on the way or thrown Mars off orbit? This is probably unfair. It's a totally different question, but I'm asking you anyway, Daniel.

• 12:33Daniel Whiteson?

  Oh, I see. Well, I was imagining that the Earth is getting tossed into Jupiter rather than Jupiter is like bullying its way into the inner solar system.

• 12:40Kelly Weinersmith?

  Oh, okay.

• 12:40Daniel Whiteson?

  So the Martians have a nice view of Earth shooting by. And then they, yeah, they could watch Jupiter as it gets impacted. In fact, we had ringside seats to a similar event in the 90s.

• 12:50Kelly Weinersmith?

  And I think you told me that you were at a telescope watching that, right?

• 12:54Daniel Whiteson?

  Yeah, I had a super fast camera hooked up to a telescope to watch this collision. This is in the mid 90s, comet Shoemaker Levy impacted Jupiter and created all these fireballs. Now, the comet, not nearly the size of the Earth, of course, but still very, very dramatic. And what happened is that this comet, which used to be orbiting the sun, got captured by Jupiter. So now it was orbiting Jupiter sometime in the 60s. And in the early 90s, it passed very close to Jupiter. So Jupiter tore it apart. It went within the Roche limit, not actually within the clouds. The Roche limit, weirdly and confusingly, depends on the object. Like if you're made out of diamond, then your Roche limit is much closer. You have to get much closer to get torn apart than if you're made out of like cotton candy.

• 13:35Daniel Whiteson?

  And so this comet got torn apart into 21 pieces, which they labeled A, B, C, D, all the way up to W. NASA very creative.

• 13:44Kelly Weinersmith?

  Of course they did. That was an opportunity for creativity. So they had to pass it by.

• 13:48Daniel Whiteson?

  And then it swung around one more time and over six days in 1994, each piece took turns smacking into Jupiter. Wow. Really amazing. And everybody on Earth was like turning their telescopes to it and watching these pieces hit. And the biggest spot is the one where the G fragment hit. And so you can imagine what that spot might be called.

• 14:07Kelly Weinersmith?

  I was just thinking that, but this is a children's show.

• 14:11Daniel Whiteson?

  Exactly. And created a huge dark spot. There was a fireball and a dark spot, the width of the Earth.

• 14:17Kelly Weinersmith?

  Wow.

• 14:17Daniel Whiteson?

  Right. Now, this fragment is a piece of a comet, which is tiny compared to the Earth, but it created a big spot the size of the Earth that was visible for a year. So we've seen this kind of impact much smaller. So essentially just scale this up much more dramatically, but still small compared to Jupiter.

• 14:33Kelly Weinersmith?

  Amazing. I wish I had watched that. That wasn't on my radar because I didn't have amazing friends like you back then. You wouldn't have let me go astray. But that's all right.

• 14:42Daniel Whiteson?

  I was in college at the time and I was home over the summer doing a research project on plasma physics. And we had a super fast camera that we were using to image what happened when you drop a little pellet of fuel into the fusion plasma. And the guy I worked for also had a telescope and he was like, let's point this thing at Jupiter. So we connected the camera to the telescope, pointed to Jupiter, and we had one of the fastest digital cameras around at the time for scientific applications. So we were hoping to have like the highest time resolution photographs of this impact. But just as the impact was going to happen, it went over the horizon. So we got pictures of the fireball rising over Jupiter, but not the impact itself.

• 15:20Kelly Weinersmith?

  Oh.

• 15:20Daniel Whiteson?

  But it was a lot of fun, anyway.

• 15:22Kelly Weinersmith?

  So wait, this was 94, though, is that right?

• 15:25Daniel Whiteson?

  Yeah.

• 15:25Kelly Weinersmith?

  Okay, so I was 12. So I probably, I was listening to Silverchair and, and I didn't care about anything other than Silverchair. So.

• 15:35Daniel Whiteson?

  Important stuff, important stuff.

• 15:36Kelly Weinersmith?

  Felt that way at the time.

• 15:37Daniel Whiteson?

  The rest of us were learning about the future impact of Earth on Jupiter. But, you know, whatever.

• 15:42Kelly Weinersmith?

  Well, I was having a good time. So I wouldn't change it for anything. All right. Brad asked if there was any chance we'd get ejected from the solar system, but you didn't mention that as a, as an option. So that's not something that would happen?

• 15:56Daniel Whiteson?

  It could happen. It depends on how accurately Brad and his supervillain team aimed the Earth at Jupiter. One possibility is it hits Jupiter, right? Another possibility is that it's captured and it orbits Jupiter. And this has happened to a bunch of stuff. We think that many of the moons of Jupiter didn't form with Jupiter, but were captured by it later. But it's a little bit unlikely because for that to happen, you have to be only at the right angle and the right velocity, at the right location, to get the orbital mechanics to work out. So more likely, you're either going to hit Jupiter, or you're going to get ejected from the solar system because you're going to have a gravitational interaction with Jupiter, which is then going to throw you out of the solar system.

• 16:31Kelly Weinersmith?

  All right. Well, one way or another, I think someone should be keeping a close eye on Brad. And let's see if our answer changes Brad's mind about whether or not this is a good idea.

• 16:43Speaker 03

  Daniel and Kelly, I absolutely love this response. I assure you that I am not a supervillain and have no plans to destroy the planet. It sounds like we would get to watch as we pass into the gas cloud layer before we heat up and explode. I like to know that we would at least have a little impact on Jupiter. I think all we need to know now is where Michael Bay wants to set up the camera to catch the greatest collision of all time. Thanks for all y'all do.

• 17:16Speaker 01

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• 18:04Speaker 05

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• 19:30Daniel Whiteson?

  All right, we're back and we're answering questions from listeners. Now we're going to take a break from Jupiter themed questions and think about sleeping. Here's a wonderful question from one of our Discord listeners. And if you're not on Discord, come join us on our Discord channel. We have lots of fun conversations about science. We answer questions on there. Other people answer questions on there. We have wonderful moderators to keep it a really happy, fun family. Come join us for science chats on Discord. You can find the link on our website. Anyway, here's the question from our listener.

• 20:00Speaker 06

  In the episode about sleep and dreams, the topic of circadian rhythms in various animals came up. I was curious how circadian rhythms work in animals that never see the sun, like cave dwellers or various deep sea creatures. Thanks for taking the question. Looking forward to the answer. Bye.

• 20:19Kelly Weinersmith?

  All right, T to the J on Discord. I gotta say, you know, this question came in and I thought, all right, circadian rhythms, I'm a biologist, I should be able to knock this answer out pretty quick. I don't know anything about circadian rhythms, it turns out.

• 20:33Daniel Whiteson?

  Oh, no. Biology is a big field, is that what you're saying?

• 20:36Kelly Weinersmith?

  That's what I'm saying. But I really enjoyed the opportunity to get to dig into circadian rhythms. Again, this is one of the things I love about the questions we get from listeners. There's so many things I thought I understood and then they give me a chance to dig into them and I learned so much. So circadian rhythms, circadian comes from the words circa dias, which means approximately a day. And I, you know, I don't know, maybe that's Latin. Probably pronounced it wrong, but you're you all know what I'm saying. So it's all right. We're good and nobody expects me to pronounce things right at this point.

• 21:05Daniel Whiteson?

  That's not what they're here for, Kelly.

• 21:07Kelly Weinersmith?

  That's not what you're here for. So circadian rhythms are like internal rhythms that happen on an approximately 24 hour cycle and they're entrained or they're sort of like synced up based on outside signals like light.

• 21:23Daniel Whiteson?

  But why do you say approximate? I mean, the earth cycle is pretty crisp. Wouldn't we do best being closely linked to it? Why are you saying approximate?

• 21:32Kelly Weinersmith?

  Uh, because, you know, it's just not perfect. And some people have cycles that are a little bit longer than 24. Some people have cycles that are a little bit shorter than 24. We think this contributes to why some people are morning people and some people are night people. And then if you're talking about organisms other than humans, you can get some other slightly different sorts of signals that are approximately 24 hours.

• 21:53Daniel Whiteson?

  So then what parts of the human body are affected by it? Obviously you sleep in this sort of 24 hour cycle. Is there other stuff going on also?

• 22:02Kelly Weinersmith?

  Yeah, lots of things. So like sleep is important. Metabolism is also important. Uh, like your body temperature is impacted by circadian rhythms.

• 22:10Daniel Whiteson?

  Metabolism. So is that why I shouldn't eat chips at 10pm?

• 22:14Kelly Weinersmith?

  That could partly be it or be involved. I think cortisol is to some extent involved in helping with digestion and stuff. And so your cortisol kind of peaks at times of day when you're like expected to be hungry and expected to be eating.

• 22:27Daniel Whiteson?

  What's cortisol?

• 22:28Kelly Weinersmith?

  Cortisol is a hormone that folks usually associate with recovery from stress. So when you get stressed out by something, your body releases cortisol and then cortisol helps your body sort of return to homeostasis or like a normal state after you've been stressed out.

• 22:43Daniel Whiteson?

  Cortisol sounds great. I should get some more of that.

• 22:45Kelly Weinersmith?

  Well, if you're like, you know, running away from a lion cortisol is great. Like it releases a bunch of energy all at once that you can outrun the lion. And then when you're in a safe spot, it helps you sort of return to normal. But if your cortisol level is elevated for a very long time, you can start having diseases because you're constantly in a stressed out state. So cortisol is more supposed to like get you out of a intense acute situation. But if it's elevated chronically, it can be bad. And there's a really interesting book on this called Why Zebras Don't Get Ulcers by Robert Sapolsky.

• 23:17Daniel Whiteson?

  Cool. All right.

• 23:18Kelly Weinersmith?

  Yeah.

• 23:19Daniel Whiteson?

  Well, I wonder if zebras go to my physics faculty meetings if they feel stressed out and need cortisol afterwards.

• 23:24Kelly Weinersmith?

  Oh, yeah. Faculty meetings. I think what I'm stressed out about in faculty meetings is that I could be spending my time way better doing anything else. But, you know, I haven't had to go to faculty meetings for a while, so that's great.

• 23:35Daniel Whiteson?

  But our question today is not about silly arguments in physics faculty meetings. It's about the rhythms of the body. So you're telling us that these things happen and impact sleep and metabolism and temperature. But what's the mechanism for it? Like, what is driving it?

• 23:47Kelly Weinersmith?

  Yeah. Okay. So, most of the work that we've done to figure out the mechanism has been done in organisms like mice and fruit flies. But here's how we think that it works, how we're guessing that it works in humans, based on what we've seen in lab animals. So, there's a little part of your brain called the hypothalamus. And inside of the hypothalamus, there's a little region called the suprachiasmatic nucleus, or the SCN, because I'm not going to try saying that a bunch of times.

• 24:11Daniel Whiteson?

  It sounds a lot like suprachiasmatic expialidocious. But all right.

• 24:15Kelly Weinersmith?

  Yeah.

• 24:15Daniel Whiteson?

  I hear that every time you say that now.

• 24:19Kelly Weinersmith?

  No one's going to be able to pay attention to the rest of the episode. They're going to be singing Just Like Mary Poppins. But try to focus, people. All right. So you've got the SCN, and the SCN is connected to the optic nerves. And so optic nerves, these are the nerves that go to your eyes. And so we've talked in the past about how your eyes have specialized cells called rods and cones. And those help you detect like, patterns and colors and to see your world. But you also have cells that just detect the intensity of light. And those cells send information through your optic nerve, back to the SCN, and your brain uses that information to tell the rest of your body how the rhythm should

• 25:00Kelly Weinersmith?

  be working. And so it does this by either sending messages through the nerves, or by directing the production of hormones that will then go to the rest of your body and talk to your cells, and basically say, okay, hey, guys, it's morning. And when it's morning, your body increases its heart rate, increases its blood pressure, increases temperature. Your body is not making melatonin at this point. Melatonin's associated with sleep. So this is generally... Really how your body collects the information about what should be setting the timing for the rhythm, but each one of your cells also has its own circadian clock.

• 25:37Daniel Whiteson?

  So we have these special cells in our eyes instead of just using the information which already exists in the rods and cones, we like evolved a separate pathway just for this. Wow, this is pretty weird engineering.

• 25:48Kelly Weinersmith?

  Well, but it's detecting something different. Your rods and your cones are detecting like colors and you know, patterns of like dark against light and stuff like that. These cells are just detecting the intensity of the light that's coming in. So you're like, oh, it's dawn now, or oh, it's noon. And so it's detecting that.

• 26:07Daniel Whiteson?

  I feel like I could write a computer program to extract the same information from the data produced by the cones and the rods, but that's fine. Obviously, the brain is not engineered by physicists.

• 26:17Kelly Weinersmith?

  And that's not how evolution works. Evolution doesn't say, okay, yeah, I'm gonna start from scratch and come up with the best system. It's like, well, what do I have and how can I work with it?

• 26:24Daniel Whiteson?

  I just think it's a fascinating clue that something happened there that this is what we ended up with, you know, it's just another example of how like, obviously, this is not well organized, just what kind of worked. And so do we know this because we've like done studies in mice where we've like tweaked those cells or gotten rid of those cells or like shined light on those cells or something, and it's changed the way the mice behave?

• 26:44Kelly Weinersmith?

  Yeah. So if you mess up a mouse or a fly's SCN, then they'll start free cycling. So essentially, they won't show these 24 hour cycles.

• 26:54Daniel Whiteson?

  They're not so expialidocious anymore?

• 26:57Kelly Weinersmith?

  That's right. That's right. It's truly quite atrocious.

• 26:59Daniel Whiteson?

  All right. So that's

• 27:01Kelly Weinersmith?

  Oh, wait, hold on.

• 27:03Daniel Whiteson?

  Okay, that was pretty good. That was really good.

• 27:05Kelly Weinersmith?

  You begrudgingly patting me on the back there.

• 27:08Daniel Whiteson?

  I was so excited about my next question. I didn't even register your joke, but that was excellent. Yeah. 10 points for Kelly for everybody who's keeping score. But so you're telling us that not only these light signals tell us when to be fragileistic, but also the rest of our body responds in some way?

• 27:25Kelly Weinersmith?

  Yeah. So, okay, so first, I just want to mention real quick that that organisms from bacteria to humans show these clocks. And so this is like, not every organism uses their SCN. And so this sort of like feeds Back on our conversation about how you just use what you have. This has like been going on for a really long time. Anyway.

• 27:44Daniel Whiteson?

  I see.

• 27:44Kelly Weinersmith?

  So not every single cell has its own circadian clock. I misspoke earlier, but many cells, even if you take them out of the body and you put them in like a Petri dish, they will show like a 24 hour schedule for the activities that they do. Like they'll repair DNA at a certain time, you know, stuff like that. And so here's how we think that works. So your cell is making a protein called clock protein. The clock protein at dawn moves into your nucleus where the genetic information is stored. And it binds to literally thousands of different sites on your DNA. And when it binds, it's telling your DNA to start making certain things.

• 28:26Kelly Weinersmith?

  And it could be making certain hormones, like it can say, hey, start making that cortisol. It could start doing, you know, whatever is needed to increase body temperature or heart rate, et cetera. So thousands of things are turned on when your clock proteins go in there and bind to lots of different spots. Another thing that's being made, though, during the course of the day are proteins that will shut this down. And these proteins are called period proteins. And so the period proteins will build up over the course of the day because the clock protein said, hey, start making these. And at some point they've built up to high enough levels that now they go into the nucleus and they pull the clock proteins off of the DNA. And that stops all of the stuff that the clock proteins had been turning on and getting made.

• 29:08Kelly Weinersmith?

  As the night goes on, the period proteins break down and go away. And then the next morning, the clock proteins go back in and the cycle starts again.

• 29:17Daniel Whiteson?

  So like many clocks, you have some sort of process which has a natural time scale built into it. Right. And so this is chemistry where things are sloshing back and forth. And naturally at the same rate as our 24 hour cycle. Is that what's happening?

• 29:32Kelly Weinersmith?

  Yeah, yeah, that's a good summary. And I saw you.

• 29:34Daniel Whiteson?

  Yeah, cool.

• 29:35Kelly Weinersmith?

  Looking something up, was I wrong about something or was it unrelated?

• 29:39Daniel Whiteson?

  I was wondering if clock was an acronym for something in a really tortured way, but.

• 29:43Kelly Weinersmith?

  Oh, okay. All right.

• 29:46Daniel Whiteson?

  I was hoping it stood for something ridiculous.

• 29:49Kelly Weinersmith?

  Okay.

• 29:49Daniel Whiteson?

  Because if it was a physics acronym, it definitely would have a ridiculous name.

• 29:53Kelly Weinersmith?

  Got it.

• 29:53Daniel Whiteson?

  Anyway.

• 29:53Kelly Weinersmith?

  So light is important for determining these cycles.

• 29:57Daniel Whiteson?

  Right.

• 29:57Kelly Weinersmith?

  But it also is fine tuned by things like the temperature you find yourself at, when during the day you're eating, and these cues are important for. Other animals as well. So it's not just light, but light does seem to be a super important factor.

• 30:10Daniel Whiteson?

  So it's interesting. You have several different kinds of things going on. Can they get out of sync? Or is there something that tries to keep them in harmony?

• 30:16Kelly Weinersmith?

  Well, so once you develop a cycle, your body is pretty good at keeping that cycle going. So like if you stayed in a dark room for two days, your body would still have some of its normal cycle. It's not like it breaks down immediately, but over time, if you deprive your body of that light cue or you mess your cues up, then you can start having problems. So for example, if you work the night shift, you know, any of us who have had jet lag have had like a temporary period where our circadian rhythm was like, something's not right. Uh, and then it's had to get back to normal. But being off of your normal circadian rhythm too often, for example, working the night shift increases your risk of diabetes, obesity, depression, dementia, and some kinds of cancers.

• 30:59Kelly Weinersmith?

  So these circadian rhythms seem to be important for, for a lot of reasons, at least for humans.

• 31:04Daniel Whiteson?

  Wow. And how widespread are circadian rhythms? So everything on earth has a circadian rhythm?

• 31:10Kelly Weinersmith?

  Well, so like bacteria, humans, plants, lots of stuff has circadian rhythms. But our listener had a really great question, which is how on earth do you have a circadian rhythm? If you live in a place with no light?

• 31:23Daniel Whiteson?

  Yeah.

• 31:23Kelly Weinersmith?

  And so, uh, there, the three different situations that I looked into where there's no light are if you are, for example, at the North Pole during the time of year where you don't see the sun. There's like, I think a couple of months where that's the case. If you live in a cave or if you live in the deep sea. And then there's also organisms like naked mole rats that live underground. But I think naked mole rats can peek their heads out every once in a while and see the sun to help and train their clock. So they get some light cues still. So let's start with if you live far north.

• 31:54Daniel Whiteson?

  Yeah.

• 31:55Kelly Weinersmith?

  So one thing that's important to note, which we touched on just a second ago, is that clocks don't go away immediately just because you're in total darkness. So at the start of the long night, they're probably fine because their body hasn't like forgotten the rhythm yet. And during the time of year when it's all light, they're probably also fine because. The intensity of the light still changes over the course of the day. And your eyes are focusing on light intensity, not just whether it's there or not. So they can still keep their rhythms at that time of year. But there is a point in the winter where their clocks have not had appropriate input for long enough, because it's been dark for so long. And they do seem to stop showing signs of 24 hour cycles.

• 32:38Kelly Weinersmith?

  If you look at the reindeer, so it looks like at some point they do start free cycling essentially, and their circadian rhythms start to break down.

• 32:46Daniel Whiteson?

  Wow.

• 32:47Kelly Weinersmith?

  They don't seem to have physiological problems associated with that. I'm not quite sure why, but it looks like they do break down at some point.

• 32:55Daniel Whiteson?

  So it's bad for them to be in the dark? Like, it would be better if they got light occasionally to sort of like correct their cycles or get them back on track?

• 33:02Kelly Weinersmith?

  Yeah, so I was trying to figure out the answer to that. And I think that the answer is to some extent that it's complicated. So, you know, part of why we have cycles is that it helps us figure out like when we should be eating and stuff like that. And part of that, if you're a wild animal, is about when your food is even available.

• 33:21Daniel Whiteson?

  Right.

• 33:21Kelly Weinersmith?

  But if you're in the dark and all the other animals are in the dark all the time, too, you might not need to have a circadian rhythm because it might, you know, if you're, say you're a fox living in the Arctic Circle, you want to make sure you're awake at the same time as the bunnies. But if it's complete darkness and everybody's free cycling, you don't really need to get up at a certain time because the bunnies could be out there at any time. And so it's not a helpful cue anymore to like have your activities sync to a certain time of day.

• 33:50Daniel Whiteson?

  I was wondering more about the internal stuff, like you mentioned earlier, that if your rhythm gets messed up, you're at risk for diabetes and cancer and stuff. Is the same thing true for reindeer from when they're free cycling?

• 34:00Kelly Weinersmith?

  Yeah, so I don't know the answer for reindeer, but I did try to find the answer to that question. I was able to find some information about blind cave fish.

• 34:07Daniel Whiteson?

  Ooh.

• 34:08Kelly Weinersmith?

  So there are fish that live in caves that have closely related ancestors that live outside of caves.

• 34:15Daniel Whiteson?

  Oh, okay.

• 34:16Kelly Weinersmith?

  And so you can compare, you know, essentially these like sister species or sibling species and see how they differ. And the species- That live in caves don't have shorter lives. And in a lot of cases, they have longer lives than their surface living counterparts. Well, okay, and then let me tell you about their circadian rhythms. That's the important piece here. So people were trying to figure out if cave fish have circadian rhythms. And they were trying to figure out like, okay, in the absence of light, how do you do that? And so one idea they had was that maybe bats that go in and out of the cave are what they're queuing into because when the bats leave or they come back, they poop in the water and that poop provides food for a lot of cave fish.

• 35:00Daniel Whiteson?

  Right.

• 35:01Kelly Weinersmith?

  So maybe that's what they're sinking to, but there was no evidence that that was actually happening. So it looks like they're not sinking to that.

• 35:07Daniel Whiteson?

  But there could be a lot of similar effects, right? Where things are happening outside the cave and like even the microbes in the air or something like that could be affecting, you could be sensing indirectly the fact that there's day and night outside the cave from inside the cave.

• 35:21Kelly Weinersmith?

  Yeah, that's right. But so people have also brought the cave fish into the lab. And when they bring them into the lab and they expose them to normal light cycles, they can develop circadian rhythms. So they still, even though they don't have eyes, they still must have like the cells needed to detect light and they can develop rhythms. But it looks like various parts of their circadian clock are messed up. So if you look at things from the genetic level, it's kind of messed up. And it looks like they also, for the most part, are losing their circadian rhythms in the cave, but that doesn't seem to be shortening their lives.

• 35:56Daniel Whiteson?

  Wow, fascinating.

• 35:57Kelly Weinersmith?

  Yeah, which is not what I expected. Like I spent a long time being like, well, no, what is the cue? They have to have circadian rhythms. And then I found a review paper that pretty much was like, their rhythms kind of seem to disappear in caves. They're just kind of like moving around whenever and sleeping whenever.

• 36:13Daniel Whiteson?

  And that's okay.

• 36:14Kelly Weinersmith?

  And that's okay. We're not judging.

• 36:15Daniel Whiteson?

  Teenagers everywhere are like, see, mom, it's fine for me to stay up until 2 a.m.

• 36:20Kelly Weinersmith?

  Right. And, and their rooms are kind of like messy caves. And I see lots of, lots of points of comparison here.

• 36:28Daniel Whiteson?

  All right. What about at the bottom of the ocean where light doesn't filter down?

• 36:32Kelly Weinersmith?

  Okay, so this is interesting. So after I had finished the research on caves, my expectation was that animals that live in the deep sea are also going to not really show circadian rhythms because they're, you know, they're down in an area where the light isn't getting to. But I thought, well, you know, maybe there's still some cues like a lot of the food that comes to the deep sea comes from things just sort of like dying and raining down. And I thought, maybe there's like a daily pattern to how the food rains down. But, but this is actually really hard to study.

• 37:01Daniel Whiteson?

  To when the carcass snacks happen?

• 37:03Kelly Weinersmith?

  That's, yeah, well, you know, I pay attention to snacks.

• 37:09Daniel Whiteson?

  Kids, dead bodies are falling. Come on outside. Well, what is it like to be a parent at the bottom of the ocean?

• 37:14Kelly Weinersmith?

  I mean, when a whale falls down, it is like buffet for months. The videos are messed up. But so the, the way that folks tend to study this is, you know, they either take the deep sea animals into the lab. But if you bring them into the lab, you're often like turning on lights to study them. And so now they're in like a not natural environment. And, you know, labs in general are not like the bottom of the sea. But another way that people study it is they will put like essentially mobile labs, they'll lower them down to the bottom of the sea. And then they'll like take pictures or videos and try to see if they can detect cycles and what's happening down there. But another problem there is that they turn on lights often when they do that.

• 37:55Daniel Whiteson?

  Yeah.

• 37:55Kelly Weinersmith?

  And so this stuff is hard to study, but I found a study that did use cameras with lights and they found that a lot of species didn't show detectable patterns, but it was also hard to get large sample sizes. But they did find that there is a kind of worm that lives in a tube. And there's a pattern to when it sticks its head out of the tube to like, try to get food. They were looking at different things that were changing in the environment. And it looks like this behavior is correlated with the tides. So you can still feel the tides at the bottom of the sea.

• 38:27Daniel Whiteson?

  Oh, wow.

• 38:28Kelly Weinersmith?

  Which is amazing. I didn't realize that.

• 38:30Daniel Whiteson?

  Yeah. Thank you, Moon. See, it's all connected.

• 38:33Kelly Weinersmith?

  Yeah.

• 38:33Daniel Whiteson?

  Turns out there is a through line for the whole episode.

• 38:36Kelly Weinersmith?

  That's right. I guess spaghetti-ification is kind of interesting. But I guess, so it's not just the tides, but the tides have different temperatures. So it could be temperature that's queuing this.

• 38:45Daniel Whiteson?

  Yeah.

• 38:45Kelly Weinersmith?

  The tides also can bring food. So maybe it's the food that's queuing the clocks. And this information is largely observational. So there's still a lot that we have left to learn. But Some indication that tides can be what's impacting timing in the deep sea. And that's literally everything I know about circadian clocks, because this is complicated.

• 39:04Daniel Whiteson?

  All right, so bottom line for us, what do we know about how circadian rhythms work in animals that never see the sun?

• 39:10Kelly Weinersmith?

  Sometimes you're poned and you can't create a circadian rhythm because you just don't have the cues. Other times you can find something that correlates with the light. Or sometimes, instead of having a circadian rhythm, you have a circatital rhythm or something and you're queuing in on some other environmental thing that can help you maintain a rhythm in your life.

• 39:31Daniel Whiteson?

  Well, I thought that answer was super counter fragileistic, but let's hear what our listener says and see if there are follow up questions. Wow, thanks for answering my question. Never would have thought that deep sea creatures could sense the tides all the way down there. That's pretty cool.

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• 40:24Speaker 04

  Hey, it's Niall Rogers, host of Before the Moment, a Lincoln original series. I'm driving across the country, meeting some of today's most fascinating artists. We're exploring the stories before the moment that changed everything. This week, I'm joined by my friend, John Legend. How does music actually enter your mind?

• 40:46Speaker 05

  I'm not sure why or how the music comes to me, but I think people who love music and write music, our brains are just filled with music.

• 40:56Speaker 04

  Right.

• 40:56Speaker 05

  Like, we have listened to so much music. We've been a part of so much music. I think of the story that I want to tell, the mood that I want to Create with the music, start playing chords, see where they lead me.

• 41:08Speaker 04

  Sometimes I'm just not even thinking about music, right? And I hear this little thing and I go, oh, that could be this.

• 41:18Speaker 05

  You know, you just have to be ready for when the inspiration hits.

• 41:21Speaker 04

  It comes. Experience before the moment. A Lincoln original series on the iHeart Radio app, YouTube, or wherever you get your podcasts.

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• 42:12Kelly Weinersmith?

  We are back to Jupiter, a fascinating planet that could kill us all. Arthur, what do you want to know about Jupiter?

• 42:21Speaker 06

  Hi, Daniel and Kelly. Nice to talk to you guys. I have a rocket thrust issue. I know that we can't escape the gravity of a black hole, no matter how powerful our rocket is, but I don't know the largest mass of a planet we can escape from with our current technology. I mean, can an average space rocket lift off from Jupiter, from the Sun, from a neutron star? I hope you have some fun answering this. Thanks.

• 42:51Daniel Whiteson?

  See Jupiter is just so attractive gravitationally. People can't stop thinking about it.

• 42:56Kelly Weinersmith?

  It's beautiful also.

• 43:00Daniel Whiteson?

  All right. So Arthur is wondering about taking off from planets because the more massive the planet, the stronger the gravity, the harder it is to lift off of. And he wants to know if an average rocket could actually get you off of Jupiter, or even more exotic and denser locations.

• 43:17Kelly Weinersmith?

  So the first thing I want to know is, I can tell from the answer, it's going to require math. Did you do these calculations? Or is there a website that has this information?

• 43:27Daniel Whiteson?

  There are a lot of websites that have this information, but I never trust them because you can find mistakes on those websites, which is the source of a lot of mistakes in like chat GPT, because it just like strips them from the websites and gives you the answer, sometimes in the wrong context or whatever. So I always double check these myself.

• 43:43Kelly Weinersmith?

  All right. Wow.

• 43:44Daniel Whiteson?

  So what matters for lifting off the surface? You're probably going to think escape velocity. And first, I want to say it's not about escape velocity, but then it's going to turn out to be about escape velocity.

• 43:55Kelly Weinersmith?

  Physicists.

• 43:56Daniel Whiteson?

  I know. So escape velocity famously is the speed you have to be going so you can escape the gravitational pull of an object. Right? So for example, if I'm standing on the surface of the earth, how fast do I have to throw a baseball straight up so that it just keeps going forever? That its kinetic energy overcomes the potential energy well that has to climb out of. Right? So as you move up away from the earth, you're gaining potential energy that has to come from somewhere, comes from your kinetic energy. If you have enough kinetic energy, then you can go forever, essentially. If your kinetic energy overcomes the potential well you have to climb. So you have to go fast to escape the earth. But the reason that's not what this is about is that that's not how rockets work.

• 44:38Daniel Whiteson?

  Right? Rockets, you don't slingshot them from the earth in one push. I mean, people are working on that and it's hilarious. But traditional rockets.

• 44:45Kelly Weinersmith?

  Why is it hilarious and not inspirational?

• 44:49Daniel Whiteson?

  It's just like the grown up version of a nine year old boy's idea for how to get to space. You know, like, let's pull back a really big rubber band, you know? I mean, I knew they're working on centrifuges and it's pretty cool, but it seems like impractical to me also because the G-forces are insane. So I think you could probably launch like stuff into space. But not people. Anyway.

• 45:10Kelly Weinersmith?

  That's my sense too. Yeah, you're launching stuff hardened payloads, not not humans.

• 45:14Daniel Whiteson?

  Anyway, that's not how traditional rockets work. If you notice when a rocket takes off, it's not going super duper fast. It's very slowly climbing, right? And that's because rockets don't have a single hard push at the beginning where they gain a lot of speed and then gradually lose it as they rise. They have a continual force, they have an engine on them. So rockets only have to go non-zero velocity in order to move up, right? As long as the force from the rocket is greater than the force of gravity from the earth, it's going to be moving up.

• 45:43Kelly Weinersmith?

  Okay.

• 45:44Daniel Whiteson?

  Right? So it can move up super duper slowly. It could take like a year to take off from the planet. Doesn't matter. It's not about escape velocity. It's about putting enough energy in to overcome the potential energy of the earth, but it doesn't have to all be up front. So that's why it's sort of not about escape velocity.

• 46:00Kelly Weinersmith?

  Okay, but so say you were lifting off at like a foot per second. That would be much more energetically expensive, wouldn't it? Because you're needing to like maintain the mass you're trying to send up as you slowly go up. And if you do it all faster, that's probably more efficient?

• 46:17Daniel Whiteson?

  It's more efficient, yeah. And if you do it all at once, just by giving it one big push, then you don't need to bring any propellant with you and you can just accelerate the payload, right? Whereas if you're climbing up at a foot per second, yeah, you've got to bring the rest of the ladder with you essentially. And you've got to lift that fuel. So we're definitely going to get there.

• 46:34Kelly Weinersmith?

  Okay.

• 46:34Daniel Whiteson?

  So what we do need to do is think about how much fuel we have to bring and how we can overcome this energy. And so you have to calculate how much kinetic energy do you need to overcome the potential energy of the earth? It's not important that it all be at once and rockets do it gradually. But the way to calculate that is to calculate what they call the delta V, the change in velocity that a rocket can provide. And in the end, this turns out to be very similar to the escape velocity. And it makes sense that it's similar because they're both connected to essentially how much energy you need to climb out of this gravitational well. And so on Earth, the escape velocity is about eight kilometers per second. That's how fast you would have to throw a baseball or launch a payload from the surface.

• 47:18Daniel Whiteson?

  But it's also very closely connected, we'll use the rocket equation in a minute, to how much fuel you have to bring with you. And that's going to turn out to be the limiting factor of whether you can lift off the planet is, can you practically bring enough fuel to get this much delta V? So on Earth, you need like eight kilometers per second. And then you go to the rocket equation. The rocket equation says, how much mass do you need to bring so that you can do this? So you can climb out of this gravitational well. Because remember, a rocket, what is it doing? It's throwing stuff out the back, right? The way it works is it's conserving momentum. Imagine you're like in a rowboat and you have a pile of bricks. You throw the bricks out the back of the rowboat. The bricks go backwards, you go forwards. That's how a rocket works. It's throwing stuff out the back.

• 48:02Daniel Whiteson?

  So you have to have that stuff in the rocket to throw out the back in order to propel it. It's helpful if that stuff also has the energy you can use to push the propellant. It doesn't have to be, you can have those things be uncoupled. But in a chemical rocket, you have fuel, which is both propellant and the source of energy. And the rocket equation tells you what your mass ratio is. So on Earth, for example, you need a delta V of about 10 kilometers per second. That tells you your mass ratio is nine, which means you need a nine to one fuel to payload mass ratio.

• 48:33Kelly Weinersmith?

  That's not great.

• 48:34Daniel Whiteson?

  It's not great, yeah. If you have like a hundred kilogram person and a thousand kilogram spaceship around them, you need nine times as much mass in fuel to get that thing into orbit.

• 48:45Kelly Weinersmith?

  Wow.

• 48:46Daniel Whiteson?

  Yeah.

• 48:46Kelly Weinersmith?

  How much worse is it for Jupiter? And does it scale linearly?

• 48:49Daniel Whiteson?

  It scales exponentially, which is the bad news, right? And so say you're on a super Earth, which has the mass of like five to 10 times the Earth. Then the escape velocity is like 25 to 30 kilometers per second. Okay, that's not so bad. It's three to four times as much, but the mass ratio is 93. It's 10 times as bad as it is here on Earth.

• 49:11Kelly Weinersmith?

  93 to one.

• 49:13Daniel Whiteson?

  93 to one. So instead of having a nine to one fuel to payload ratio, you have a 93 to one. One fuel to payload ratio. So now like your rocket is basically just fuel, right? And that's just for a super earth. Now go to Jupiter. Jupiter is so massive that its escape velocity is like 40 kilometers per second. And this gives a mass ratio of more than a thousand. Wow. Right? So you'd need a fuel tank that's a thousand times bigger than your payload. This is probably even an underestimate, but essentially this is impossible for chemistry, right? The chemical rockets cannot achieve this. And if you went to the sun, right, then the escape velocity from the sun is 400 kilometers per second. And so now the mass ratios are just

• 49:55Daniel Whiteson?

  astronomical. From a neutron star, the escape velocity is four tenths the speed of light. So I couldn't even get my calculator to give me a number on this, which is so big. And so the bottom line is that chemical rockets, where you have this fuel and you're slowly climbing out of the gravitational well, they work pretty well if the escape velocity is low, because the mass ratio is pretty small. You can afford nine to one, which sounded bad already to you, right? But on a bigger planet like a super earth, it's pretty hard to use. And on Jupiter, or the sun, or neutron star, it's definitely not practical.

• 50:30Kelly Weinersmith?

  So what about like a Project Orion style propulsion system? So if you were exploding nuclear bombs out the back of your rocket to send you up, could you get off of Jupiter?

• 50:41Daniel Whiteson?

  Yeah, you could. This is limited to chemical rockets, right? And you can have other strategies. You could build a space elevator, right? You could have nuclear propulsion, absolutely. And especially if you're launching the nuclear weapons behind the rocket somehow, so that they don't have to come along with the rocket, then you can escape this trap of having to bring all of your propellant with you. Yeah. Or if you have like a lightsail with a laser behind it, you can use that to lift off of a planet. Or you could just build your thing in space anyway. Why are you building it on the surface of Jupiter? That doesn't really make a lot of sense, unless that's where your supervillain hideout is. In which case I have to wonder, Jupiter doesn't get a whole lot of light. I wonder how your circadian rhythms are going in your supervillain lair.

• 51:24Kelly Weinersmith?

  Well, you better hope that Brad isn't sending the earth careening into your, your supervillain lair on Jupiter.

• 51:30Daniel Whiteson?

  Oh, maybe he's saving us, right? Maybe he's using the earth. That doesn't really work, does it? Using the earth to crush somebody else's supervillain lair? Yeah, not a great plan, Brad.

• 51:39Kelly Weinersmith?

  I'm not paying you to write that plot, Daniel.

• 51:44Daniel Whiteson?

  So yeah, chemical rockets work essentially only on smaller planets. On bigger planets, you need other technologies, but those technologies are not impossible. So I think if we did evolve on Jupiter or on the surface of a neutron star, technically, it's still possible to get off of those, but not with rockets.

• 52:02Kelly Weinersmith?

  All right, let's see if Arthur has any follow up questions and maybe he'll tell us what his supervillain plan is.

• 52:09Speaker 06

  Thanks, guys, for the kind answer to my question. I knew that lifting off from a bigger planet would be hard, but I didn't knew it would be almost impossible, at least for chemical rockets, as you explained. I think that this either puts a big risk on plans for space exploration, since the range of celestial bodies we could visit would be very limited, or either forces research for more efficient technologies, as you mentioned. All I have to say about supervillains is that they love rockets these days. So I do not doubt they have plans for this massive madness. Thanks a lot.

• 52:47Daniel Whiteson?

  All right. Thank you, everybody, for sending in your questions. Remember, you can write to us to questions at danielandkelly.org and send us your thoughts about the universe, your musings, your wonderings, your philosophical meanderings. Please, we'd love to hear from you.

• 52:59Kelly Weinersmith?

  Can't wait to hear from you.

• 53:00Daniel Whiteson?

  Thanks, everybody. Stay curious.

• 53:09Kelly Weinersmith?

  Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio. We would love to hear from you.

• 53:14Daniel Whiteson?

  We really would. We want to know what questions you have about this extraordinary universe.

• 53:20Kelly Weinersmith?

  We want to know your thoughts on recent shows, suggestions for future shows. If you contact us, we will get back to you.

• 53:27Daniel Whiteson?

  We really mean it. We answer every message. Email us at questions at danielandkelly.org.

• 53:33Kelly Weinersmith?

  Or you can find us on social media. We have accounts on X, Instagram, Blue Sky, and on all of those platforms, you can find us at D and K Universe.

• 53:43Daniel Whiteson?

  Don't be shy. Write to us.

• 53:47Kelly Weinersmith?

  With ChatGPT, you can do more than get answers. You can get things done, whether you're leading a big project, planning an elaborate trip, or trying to balance work. In life, ChatGPT can help. Give it a goal, plus things like files, notes, or project plans. Develop a trip itinerary with daily updates or create a prioritized schedule. So you can spend less energy sorting out the details and more on bringing your biggest ideas to life. Get started at ChatGPT.com.

• 54:14Speaker 03

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• 54:29Speaker 04

  Combining power for work, tech for adventures, and style in between. Built on reputation for quality and reliability. Toyota trucks are known for holding their value, which can mean big savings when it's time for your next Toyota. So get a great deal today and great value tomorrow. Shop Toyota.com for more. Toyota, let's go places.

• 54:49Speaker 01

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• 55:19Kelly Weinersmith?

  This is an iHeart Podcast. Guaranteed human.