Dear Hank & John - 390: Breathe Mars (w/ Dr. Katie Mack!)

Episode Date: May 29, 2024

If everything was the exact same color, would we still be able to see? Why can't I take naps in contacts? How long does it take to get to space? What would you bring to Mars? How many people are asleep right now? If atoms are mostly space, why don't I fall through my chair? Hank and John Green have answers!  If you're in need of dubious advice, email us at [e-mail] us for monthly livestreams at patreon.com/dearhankandjohn.Follow us on Twitter! twitter.com/dearhankandjohn

Hello and welcome to Dear Hank and John. Or as I prefer to think of it, Dear John and Hank and Dr. Katie Mack. Hello. It's a podcast where two brothers, and sometimes a special guest, answer your questions, give you dubious advice, and bring you all the week's news from both Mars and AFC Wimbledon, and also talk about the universe together. John, one time at the end of my physics lecture, I went to my professor and I said,

what happened before the Big Bang Bell? And he said, sorry, there's no time. That's the bad joke that we're gonna have. Dr. Mack, is that funny? Good answer. It's hilarious though, yes, definitely. So we're joined today by noted Canadian American astrophysicist, Dr. Katie Mack, who is the co-host with me of a hit new podcast called Crash Course the Universe that is the history

of the entire universe, right Katie? Yes, we're doing the whole thing. Yeah, not just- We tell the whole story from the first second until the deep future. Before the first second. I'm sorry, excuse me. We take like half of episode one to get to second. That's true.

There's a lot of pico seconds involved, a phrase I didn't even know before this. But then you also look at like what's going to happen because we can draw the line out pretty effectively. This podcast was really inspired by my reading of Dr. Mack's incredible book, The End of Everything, astrophysically speaking, which discusses the end of everything and really got my head going. It's not that discouraging to me personally because I won't be here, but some of my protons will be. Yeah. It's all the same stuff. It's very weird that I can lose my AirPod, but it's definitely out there somewhere. We know that for sure. It's somewhere. Yeah. Yeah.

If you think that's weird, wait until you hear about how protons sometimes have things that weigh more than protons inside of them, but they still weigh what a proton weighs. It's infuriating. It's apparently it's just all the protons are just sharing that one big particle amongst them. That's the only way it makes sense, right?

No? Is that it? No, it's not that simple. She didn't like that, John. I mean, I wouldn't even be surprised if it was that way. Like it just, it's such a mess, it's such a mess. That whole quantum, oh my gosh. Yeah, I do sometimes-

Once you get into quantum stuff, it gets really mind blowing. And that's one thing that we get to in the podcast, just a little bit. We're not trying to like teach graduate level astrophysics here. We're just trying to get regular people like me excited about being in a universe, being part of a universe. We're not just looking at it, we're made out of it. Yeah, it's real weird. It's wild. So anyway, check out the new podcast, Crash Course, The Universe. I think one episode

is on the Dear Hank and John podcast feed, but if you want more than that, you got to subscribe wherever you get your podcasts or watch it at youtube.com slash Crash Course. If everybody goes and does that right now, then it will shoot up the charts. I just want everyone to know. You'll be the number one podcast in America. That shooting up the charts, that's a big deal. It matters. Yeah. So just give it a checkout. Click the little button.

We're just looking to replace Joe Rogan at the top of the hit list. Wouldn't that be a thing? It's a worthy cause. Yeah. It's a worthy cause. I think for the whole universe. Absolutely. We've got some great questions about the universe. Got some weird ones. Mostly for Dr. Mac, but a little bit for me now that I've asked a lot of questions about the universe. This first one comes from Ahena who writes, dear John and Hank, when the universe expands, do existing stars and clouds

of gas and star nurseries move to take up that space like how gas fills the entire available space or is new matter actively created in that expanded space? What will this new matter be? Did the Big Bang create all the matter that will ever exist in the universe? Very confused, what is going on? I feel like you can actually answer this one, Katie. What will this new matter be? Did the Big Bang create all the matter that will ever exist in the universe? Very confused. What is going on? I feel like you can actually answer this one, Katie. Yeah, this is a great question. The idea that as the universe is expanding, more stuff is being created was one of the

big theories about the universe back in the day, early 1900s, sort of. Well, yeah, some of them in the first half of the 1900s. This was the idea of the steady state universe, right? And it might have been a little later than that. But anyway, there was this idea that the universe is expanding, but like new matter is showing up. So it looked the same all the time. Like there'll always be the same amount of stuff. And now we really don't think that's happening. What it looks like is that everything's getting farther apart and there's just more empty space. Right. It's the same amount of stuff as always.

Yeah. So what we see when we look at the expansion of the universe is that things are moving away from us. Things are moving away from each other, there's more space in between stuff. And to be clear, that's only happening on like really large scales. So between distant galaxies, there's more space happening. Between the Earth and the sun, there is not more space happening. Right. I'm not getting bigger.

I thought that for a second. That like maybe space just gets bigger, but how would we know if it was happening if we are also part of space? We just, maybe humans used to be tiny and we're gotten, but no, we are the same size. Yeah, yeah, all the stuff that's sort of bound in some way is staying bound in that way, right?

So the galaxy is gravitationally bound, the solar system is gravitationally bound. Clusters of galaxies are gravitationally bound, those things stay together, but the sort of more distant things between, you know, more distant things where there's a lot of space in between are just getting farther apart. And so the density of matter in the universe is going down, the density of radiation in the universe is going down over time. The one thing that the density does not seem to be decreasing is dark energy. And there's a lot of research into this and things are getting messier. But it appears that dark energy kind of remains at a constant density because it seems to

be just something that's tied up in how much space there is. There's a certain amount of space, there's a certain amount of dark energy or cosmological constant in it. And so if that's the case, if it really is a cosmological constant, that's just a constant of the universe, then the amount of dark energy is not changing. The amount is changing, but the density is not changing, if you see what I mean. There's more space, there's more dark energy. That makes total sense, by which I mean, it does not make any sense at all. But I was going to say, I mean, I thought it makes sense to somebody because to me, dark energy itself, the cosmological constant itself puts me at the very edge of where I can understand

the idea that there is an energy that's constant that we don't understand and can't observe is a little bit of a mind blower. I get a pretty strong, like, this is a current, like, we have to have this here for things to make sense. But like, it's just sort of making things make sense right now. It's just a constant, basically. I mean, what we see is that the universe is expanding. What we see is the expansion of the universe is accelerating.

And so we have to call whatever's doing that something. We call it dark energy. A cosmological constant is a kind of dark energy that we've theorized that is just tied to how much space there is. It's a sort of property of space. And that seems to fit the data for the most part. There are a couple of places where we're a little unsure at the moment, but it seems to fit. And if that's the case, then yeah, there's this weird stuff that's just kind of built into the universe that causes more expansion. And when there's more space, there's more of that, so there's more expansion. That's why the universe is accelerating in its expansion.

But we don't have an explanation for it at any level. There are theories, but we don't have anything where we can say, this is what dark energy is, this is why it's like that. It's a huge mystery, really. The point of that is that, yeah, the amount of matter seems to be staying the same, which means the density of matter is going down. The amount of radiation seems to be basically staying the same, although radiation and matter are kind of turning into each other in certain ways. of radiation seems to be basically saying the same, although radiation and matter turn into

each other in certain ways. The density of that is going down. The density of dark energy is possibly not going down. So there's something that's there's more of it as there's more space, but it's not matter and it's not energy. Yeah. So does this mean that time is really just things getting further apart? Oh boy. I don't know if we needed to bring time into it. No, but that's an excellent segue to talking about the way that we talk about time as cosmologists. So in general in cosmology, we don't talk about time in terms of billions of years. We talk about it in terms of, well, we usually use redshift,

which I'll get to that in a minute, but that's tied to what's called the scale factor, which is the size of the universe. So when we talk about seeing a distant galaxy, we're really tying that galaxy to how big the universe was when the light left that galaxy and came to us. And so- Because we can only see that galaxy as it was however long ago it took the light to travel to us. Yeah. And so you're saying that the eight, you're not thinking about time, you're thinking about the size of the universe. You think about time as size. Basically, yeah.

That's like the timeline we use. Yeah, yeah. So what we actually observe is we see the light from that distant galaxy. We see that the light has been stretched out by the expansion of the universe in the time that the light has been traveling to us. And the amount that that light has been stretched out is called the redshift. And we sort of order things in time by redshift rather than by time because we can observe the redshift directly. We see exactly how much that light stretched out. But in order to connect that to a number of years ago, we need to apply

our cosmological model that connects how the universe has been expanding over time. When we talk about a distant galaxy, we talk about it in terms of, oh, that's a redshift 10 galaxy, or oh, that's a redshift 3 galaxy. That's how we order things in terms of like, oh, that's a redshift 10 galaxy or oh, that's a redshift three galaxy. And that's where we, that's like how we order things in terms of how long ago that thing was shining. So you literally measure time by measuring space, measuring the size of the universe at that time. Yeah, yeah. But then somebody has to write a headline about it

and so you have to tell them a number of years. And we have to do that calculation every time, right? Like whenever there write a headline about it and so you have to tell them a number of years. We have to do that calculation every time. Whenever there's a headline about the most distant galaxy observed or JWST is seeing a galaxy whatever number of years, what we do is we say, okay, we see a galaxy at red shift 11.2 or whatever and we have to go back to our models and stick it in a calculator and calculate, okay, how many years ago was that? Yeah. But what we do know is how much smaller the universe was

when that light was emitted, which is, it's weird that that's the thing we know, but that is very upsetting. Yeah, it's a strange thing to have. It's strange that we know more about the size of the universe in the distant past than we do about time. Like how many seconds have gone by? Yeah. Yeah. Okay, let's move on to another question because my head is starting to hurt and my stomach

is also starting to hurt because I know that if everything just keeps getting further away from everything else, that is over time what we know as a proper issue. This question comes from Nisha. It's a level one emergency. Nisha says hello. I know. We know what you're talking about. Right, Katie? We have a level one emergency long term. It's going to get uncomfortable eventually. I mean, we're going to talk about that more in the podcast, but yeah. Okay. But yeah, we have- If things keep spreading out- I call level one emergency something that's going to deeply affect me or the people I love or my

descendants. And I feel like cosmologically, we have a level one emergency. Yeah, great. But I was just wondering the good news that for the moment, things are pretty stable and will be for a while. But Nisha has a problem and things are not stable for Nisha because it's 2 AM and my bed just broke and I need to figure out how to fix it without turning the lights back on. I don't know why. And I also don't know why you had to bust out your phone and email us instead of dealing with the matter at hand. But Nisha is out of college. I mean, Hank, have you ever had a problem that you could distract yourself by using your phone with because that's what people do? I guess. Yeah, I do do that a lot. Nisha wants to know,

can we not see stuff in the dark because everything looks black? If everything on Earth was always the exact same color, would we be able to see anything at all? I need a new mattress, Nisha. Wow. If everything on Earth were the exact same color, would we be able to see anything if there were no color distinctions? If everything on Earth was black, like deep pitch black, vantablack painted like matte black, it might be pretty hard to see stuff. If you had light, you could still see outlines, right? You could still see depth. Not if it was like, if it absorbed 100% of the light,

you couldn't. Right. Which is very hard to get. Yeah, so if you had like super vantablack, right? Like where there's no reflections at all. Yeah, it would be a proper issue. Yeah. I think it would just look black,

even if the sun was out. But if it was any other color, it would be shades of that color. So if everything was beige, it would be shades of beige and that you would just see the world as a person who has monochromatic vision, like a color blindness where they can only see one color, you would see the world like that person does. How would you know to hate the franchise currently applying its trade in Milton Keynes? Would that mean that you couldn't have soccer?

No, John. Because you couldn't tell who your teammates were. We would find ways to tell the stories. It just be stripes versus solids. It'd be stripes versus solids, shirts versus skins, old school style. You need two colors for stripes. Great point. Oh no, I don't know what I was thinking. This is why we

have a proper scientist on the podcast. You do need two colors for stripes. You would need to make the players different shapes. I don't know how you're going to do that, but that's what you need to do. Yeah, you could have the hats. You need to make one Jersey circular and one jersey rectangular. That would be tricky. That would be tricky. No, there'd be a slight home advantage because you could wear a regular shirt instead of having to wear a big puffy shirt. Yeah, you'd have to wear a Michelin man shirt. It could be anything. Yeah, you'd have to wear a Stay Puft Marshmallow shirt. Yeah. Remember that AI thing where the pope was wearing that big Balenciaga coat? Yeah, wear one of those. It'd be like that. Or it could be just crop tops versus regular shirts.

I don't know if that's enough. Like I don't know if just glancing you could tell. And it's good enough for me. All right. I think I'm going to put half the players in tight little crop tops. Tight shirts versus loose shirts might work. You could just make one of the players jerseys shiny. Hmm. What's shiny? Is that color? No, that's just reflection.

Like we've established you're allowed to have reflections, right? It's not all Vanta black, right? Yeah. So you make one of them like a shiny finish and one of them a matte finish and then you can easily tell them apart. You could even make the stripes out of shiny versus matte if you really want to.

It'd be technically the same color. They'd just be different albedo. I think we've got a potentially new branding opportunity for AFC Wimbledon, the shiny and matte stripes. The next question comes from Kristen, who writes, Hey, John and Hank, I recently got contacts and the internet is telling me I can't take naps in them. Kristen, Kristen, just ask your optometrist. Don't go to the internet. Don't ask Google. Is that a real thing or is cleaning, is it like

cleaning your ears with Q-tips where everyone says you shouldn't do it, but you can? No, Christin. Oh no, you're approaching your facial health all wrong. Yeah. So it is very much like Q-tips in that people do it, but you shouldn't. It depends on the length of the nap, in my opinion. If you're going to take a 15 minute nap, it's fine. You can take a three hour nap. I can't be the person to ask because I had contacts for like six months and then I lost them in a mosh pit and I was like, I'm not getting those again. Dr. Mack, do you have good vision or do you have? I have excellent vision.

I have sniper vision. I got an eye test once and the optometrist told me I should become a sniper. Wow, that's a weird thing to come out of a medical appointment. It really was. You should do killing. Yeah, it was a little concerned. When that was the sort of obvious upshot of my special skills is like, oh, you can kill people from a distance. Congratulations. No, I don't want to do that.

Yeah. It's like there should be other things I can do. Does it help in cosmology at all? Do you feel like you can pick out a distant galaxy that others miss? No, it does help with flying though. It's actually very good for that. I can spot the airplanes from very far away and the people I'm flying with cannot see them. You can't tell Katie Mac that sneezing isn't normal. I almost just sneezed and sneezing is very unusual for humans and it would have made me feel very disturbed, but I would manage to hold it in like a normal person would. Yeah. I'm glad that you have

supervision as a pilot. I always forget that you're a pilot because I feel like we're friends and we have fairly similar value systems. And then you come out with, also I fly airplanes and I'm like, no, we're completely different. You're fundamentally different human beings. Yeah. You're much closer to a dolphin than you are to me. It would be my presumption from the fact that you fly airplanes. I have no idea what it is like to have an urge to fly an airplane. No, I don't have that one either. It's a lot of fun. It was kind of a pandemic hobby. I got a little stir crazy sitting at home too much and I needed to get outside and then there was this little airport nearby and I was like, well, I'll try that. And then I got really,

really obsessed with it kind of unexpectedly. But it's fun. Can you fly like a 747? No. I don't know how that works. No, I can fly a single engine airplane, specifically a single engine land airplane, not a sea plane. And I am learning to fly multi-engine, but that's just two engines and they both have propellers. I can't fly jets. But if you had to, would you be one of the people who was like, I get like, if nobody else. I'm saying like, if the pilots are incapacitated

and the flight attendant is like, hey, can anybody land this 747? Do you like your odds? I like my odds better than anybody who's not tried it, or has not flown an airplane at all. Yeah, I think that, you know, there was a survey going around a while ago, like, do you think you could land, you know, like, a bunch, you know, do you think you could do a bunch of different things and like, fight

a bear or whatever? And one of them was landing a 747. And I felt like, you know, I have decent odds that like I could get the plane onto the ground and we would at least mostly survive. I think that's- Right. They'd need to get a new plane, but no, but he would need new bodies. That's the hope. Yeah. So just to go through that questionnaire real quick, I could not fight a bear. And I am baffled by anyone who thinks they could fight a bear. I think I could talk a bear down off the ledge. I don't think I could fight a deer. No, of course not. I could barely fight a raccoon and they weigh 20 pounds. I think about this sometimes when I see a coyote and the coyote

will be like, whoa, whoa, whoa, sorry, man, didn't mean to get in your way. And I'm like, are you kidding? You could win. You would have a great chance. Yeah. This is a lot of food I'm carrying around these two legs. I definitely could not defeat a bear. I feel like I could intimidate a bear, but my best self would be intimidating a bear. My best self would be like, hey bear, and raising my hands up and I'm a big, bad, scary human. You better walk away from me. My actual self would literally just crumpled into a ball and wait for the bear to take me. You never know what's going to happen until it happens. This is what you learn. I also could not land a plane, right? Like even

with all the air traffic controller people being like, I think I might get lucky with the bear. There's 0% chance. I might get lucky with the bear. I have a 0% chance in the plane. With the bear just sort of like losing interest or being like, ow, that hurt too much. You poked me in the eye and there's berries nearby. That's not going to happen in a plane where the plane's like, oh, I'll just land myself since it seems like you're having such a hard time. I feel like that's our biggest green flag, Hank, is like we know our limitations. We don't know all of our limitations. That's true. That's a really good point.

I keep running up into them all the time. Do you know the limits of your knowing your limits? That's true. You do run up against the limits of your own talent a lot when you work in a creative field. You should take your contacts out before you take a nap, but you probably don't have to. And this is the thing, this is the thing with the Q-tips too,

where it's like, yeah, but, but you shouldn't. It pushes that wax in and then you have to get a doctor to take it out. Or. Yeah. Or. Oh no. You use, just use an ear candle.

Those are totally effective. Or you could just sort of like wave a wand around it and pray. This question is from Rowan who writes, hi John and Hank, I'm Rowan and I'm five. Okay, first off Rowan, no bragging. Okay? That sounds awesome. Very impressive that you can type and everything. That's great.

If I fly a real spaceship, how many minutes will it take me to get out of the atmosphere and into space so it's dark and stars and stuff? My dad says he has literally no idea. Also, what is literally? In my boat, Rowan. There's no way Rowan wrote that joke. I'm sorry. I think dad wrote that joke and it's a great joke. Can I tell you guys something that happened to me last night? By the way, there's no way five-year-old Rowan made it through that first question to get to this one. I was reading- What happened to you last night? I was reading Orin a book and then he moved all but one of his stuffed animals to one side of his bed. And then he interrupted me while I was reading the book and he pointed to his pile of stuffed animals and he said, Germany.

And I was like, what's happening right now? And then he pointed to the one stuffed animal on the other side of the bed and he said, Gerfew. It's pretty good. I was like, I made it like a loud noise. Anyway. I'll be honest, I think it's good, but I think it's worryingly in the brand of Hank Greengrass. Yeah, yeah. I'd like to see Orin branching out into a little bit less of a punny land and more into the moth joke.

I have no control over him. More into existential jokes. Yeah, I'd love for him to be the newoth joke. I have no control over him. More into existential jokes. Yeah. I'd love for him to be the new Norm MacDonald, but he's taking his own path. Rowan and Alexander, it's just going to matter how fast your spaceship goes. They can go all kinds of different speeds. Can they though? Like don't they have to go fairly fast just to escape the atmosphere?

They have to go 11.2 kilometers a second to Boom. I thought somebody might know the answer. Wow. What a pleasure it is to be potting with an actual expert instead of a professional speculator. Why can't I just go 11.1 kilometers a second but just keep going? I bet Dr. Mack has an answer. There's a little force, Hank, called gravity. No, it's not that. It's not that. Let me answer. Maybe you've heard of it. It's the weak nuclear force, Hank. It's the strong one. It's definitely one of the forces. So if you just, well, okay. First off, a bunch of men who don't know anything. Hank, let's just acknowledge what's happening, which is that a bunch of men who don't know

anything are talking over a woman who knows a lot. Okay. So I know that 11.2 kilometers per second is the escape velocity. I don't actually do rocket science. I do the other kind of complicated science stuff. So I don't know the details of what happens. So if you are launching from the surface of the earth and you just give yourself a speed, it has to be 11.2 kilometers per second. If you are accelerating as you're going, you're

going to be at a place where the force on you from gravity is a little bit less. And then that means that the escape velocity is a little bit less, right? It gets a little bit tricky in terms of as you're moving, the system is kind of dynamical. But you have to get enough energy to at some point balance out the gravitational pull and the gravitational potential energy. So the total kinetic energy that you get from going 11.2 kilometers a second in the direction away from the center of the earth, that's going to balance the gravitational potential of being pulled toward the center of the earth. That's the thing you're trying to balance. But in terms of like what the speed looks like if it's changing, when

it has to be at what speed. Right. Because you're not going to start out going that speed. So the real trick is how fast can you get to escape velocity. And that you can do that acceleration at a number of different accelerations. Right. And that Rowan, neither of these people is answering this question in a way that makes sense to me, let alone to you. Well, in terms of how many minutes it gets to get to space,

like that's a different question, right? Cause that just depends on how fast your spaceship is at the moment when it launches. And I think that's like a few minutes. Like it's not very long. Not as long as you think. I would say it's six minutes, Rowan. I think the answer to your question is six minutes.

It could be faster if you don't mind being real squished for a long time, but they gotta take account of the squishable parts of the inside of the spaceship, which is gonna be you, Rowan, when you grow up and you're an astronaut. And it also, it doesn't take very long to get to the space station either. That's like a few hours if you depending on how you do it. Until they dock.

You can get to the International Space Station. That was sort of thought of just the part where you try and you have to match the speeds up. Yeah, I don't know how long it takes to actually dock, but like I've seen launches where they're like they're there in six hours. I think they can get there in four, depending on how they do it. That must be really weird. They can get there fast.

That must be a strange thing. I'm really glad that I'm never going to experience it, although it sounds like both of y'all might. It sounds like y'all might go to space if you had the opportunity. I would totally go if I had the opportunity. Yeah, I put it in application. So NASA had a call a couple of months ago and I put in my application. Are you serious? Yeah. For space stuff. It would be fun to have a friend who went to space, but not as fun as having all my friends on Earth.

Yeah, no, I would be very scared. I have some friends who are astronauts. I do. I have some friends who are astronauts. I have not ever watched one of them launch. That would make me very nervous. Yeah, yeah. I couldn't even watch the web launch. I was too scared. I should have, but I...

If you were selected to be an astronaut, you would go. Oh, absolutely. Would you go to Mars? Yes, yeah. Really? 100%. Yeah, yeah. Would you be in the first group to go to Mars? Sure, sure.

Well, I mean, that's almost even better because then you're like, then you're just like one step for a man. Yeah, so like, I feel like if I were, if they made some kind of habitat on Mars where you could live for like years, I would not even necessarily require a return ticket. Like I would go, I would just go.

Wow. I mean, I wouldn't go if it was like, you've got like three hours. You would go to Mars without the ability to return to Earth. Yeah, I mean, if it were the sort of thing where they were like, you've got like three hours. You would go to Mars without the ability to return to Earth. Yeah. I mean, if it were the sort of thing where they were like, you've got like a couple of days of oxygen, I'm not doing that. But if it were long-term habitat, yeah, I'd live the rest of my life on Mars. You knew you were going to die up there and you probably going to die up there maybe a

little earlier than you would on Earth because the medical care isn't going to be the same. Yeah. Yeah. What's a few years? How many things can you really do in life? I like the idea of us sending like 10 people to Mars and then they just get old there. And eventually, this is like 10 85 year olds on Mars. I am speechless.

Yeah, yeah, I that's not I wouldn't sign up for that. I got a lot going on here. I just I just think it would be worth it. Yeah, I wouldn't sign up for that. I got a lot going on here. I just think it would be worth it. The number of things that I feel like I could accomplish in life, there's a number of things I could accomplish in life, but I feel like going to Mars would be higher priority than any of those things. They would be more interesting, cooler, more exciting than any of those things.

So yeah, I would replace a bunch of those earth things with that, absolutely. But don't you think it would be harder to do your fundamental cosmological work, like your work as a cosmologist? Oh, there's other important work to be done on Mars. Yeah. I mean, I could become a geologist. I could go out and look at rocks. And on my down time, I could still read papers and do calculations, I'm sure. I think it'd be fine. Yeah, but you are stuck with the computer that you get when they send you. That's true.

I guess not. Maybe they'll send you more computers. They could send more, yeah. When I said earlier that I feel like if I were a person, you'd be closer to a dolphin in terms of our differences. I actually dramatically underestimated our differences. It's much more like- I hope this doesn't get in the way of our friendship, John. It's like you're a person and I'm a tuatara. I have no idea what it would be like to be willing

to go to Mars, let alone be willing to take a one-way ticket to Mars. I mean, you don't think it would be exciting? Like just exploration. You know what's exciting is like going for a walk in the woods and there's a small chance that you'll see a tufted titmouse. That's exciting. I'm very nervous. And I think like, we don't think about this with the moon,

but like we didn't really know enough about the moon to go to the moon safely. It turned out okay. But like when the moon got into the, you know, into the lander, like some moon stuff, like, I don't know, you're gonna have to breathe that stuff in. What's it made of?

Is it better or worse than asbestos? And that's how I feel about Mars. I'm like, I'm gonna go to Mars and I'm like, I'm gonna be there for years, I'm gonna be breathing a lot of Mars. And I don't know that I want to breathe Mars. There are, we have bits of Mars. We have, we do. From meteorites, right?

And we have, we just analyzed a lot of bits of Mars on Mars. Yeah. And we've analyzed bits of Mars on Earth from stuff that's been sort of knocked off of Mars. And we're working on sample return. So, you know. I hope that that works. From what I know of Mars, I wouldn't want to pre-fix. I'm just saying sample return is a very far away from human beings return. I'm anxious. I'm like, I'll be honest, my armpits are pouring sweat right now. We're talking in hypotheticals, John. Katie's not leaving soon. Katie could go to Mars anytime now. This This is now, this is a reality.

It's a very present concern for John. Katie's willing to be the first part of the first group, and she's a well-known astrophysicist. They would be silly to turn down her application. There's like a 60% chance that Katie's going to Mars, Hank. Dr. Katie Mack, what would you bring to Mars that you wouldn't need? Oh, that's a great question. I would say books, but they're just so heavy and probably I could get, I could get, you know, stuff on a Kindle or something.

Yeah. Hmm. I don't know. I'd have to think about that. You want to just like leave like your childhood stuffed animal, like on a little hill? I mean, you know, I'm not that attached to any, I used to have some that I was really attached to and I'm kind of like, they're in a drawer somewhere. I'm not sure. I'm really not sure. I feel like I'd have to take something small and sentimental to remind me of my family or something

like that. But I don't have anything that I can think of at the moment that's like, you know, I have to have that with me. That reminds me that today's podcast is brought to you by the raw blind panic of your friend potentially going to Mars. The raw blind panic of your friend potentially going to Mars. A new and exciting feeling. This podcast is also brought to you by the Earth's escape velocity, 11.2 somethings per second. Kilometers? Kilometers. We also have a Project for Awesome message from Josh and St. Louis to Rachel. Rachel, you are a profoundly capable person and I am so very grateful to have you in my life. I am proud of all the ways you are changing and growing and I'm excited to support you always in your journey

to make yourself who you want to be. Every new day with you is my new favorite day with all of the love in my heart, Josh. That's so lovely. Thank you, Josh. Thanks for donating to the project for awesome. This next question comes from Rory who asks, Dear Greens and Katie Mack, when was the last time more than half of the global population was asleep? Was it okay? And how many people are asleep right now? Rhymes with bedtime story, Rory. I actually looked into this. And every day, most people are asleep for a little while. No way. Yeah. Because most people all live sort of in a pretty specific. So like, two things. First, you got to know that a lot of earth is the Pacific Ocean.

It's hard to remember that because it's not on our maps, but it's like half of earth. So those like those- I would argue it is on our maps. Well, it's not on a lot of them. We don't put it on a lot of maps because like we cut, like in order to make it into a map shape, we cut down the middle of the Pacific Ocean

and then we sort of squish it out onto the sides. Okay. I would argue it's still there, but that's all right. Really, really, really don't want to let this one go because I'm right. It is there. It does say Pacific Ocean on the maps. Yeah. It's not like we like canceled it or something. It's not like we like don't put Hawaii on the maps because it's in the middle there. Yeah. We squish it all together. But anyway, there's a lot of earth that there's not a lot of people on because it's the middle of the Pacific ocean. Um, but then the sleep band is more narrow than the wake band, of course,

because people sleep for fewer hours than they are awake, but there is kind of, you can sort of roughly gauge a sleep band that is about eight hours and it's about from, you know, maybe 11 o'clock at night to seven o'clock in the morning. And we're just sort of like fudging because around the edges that like there's going to be people sleeping at different times in different places as well. But that when that sleep band passes over Asia and India, there is a time when like pretty much, when more than, when like probably like 70% of people are asleep, which is wild.

But also weirdly because of the Pacific Ocean, there is a time every day when like 95% of people are awake because the awake band is much bigger, which doesn't ever seem like that to me because I'm constantly trying to do business with people in other parts of the world and they are always asleep, it seems like to me. I can never call them. I wonder if the sleep band, you know, as population ages change, that's going to change too because

old people don't sleep as long and babies sleep much longer. Yeah, and there's just fewer babies and more old people every year on the earth. Yeah, that sleep ends gonna sort of narrow a little bit. And also maybe move a little earlier in the day. Yeah. All right, Hank, I got another question from Catherine who writes, Dear John and Hank and Dr. Mack, if atoms are mostly space, how can they support our weight? Why don't I fall through my chair? Questionably solid, Catherine. So this is a great question.

I feel like I'm not made of mostly empty space. So first of all, defining empty space is complicated because there's energy all throughout space that you can't really localize where particles are. So they're kind of like, part of their wave function is sort of everywhere, you know? And so like, you can't really say that an electron is not in certain space. It's just like, there's a probability it's in that place. So that whole thing is a little bit unclear. But the reason that things feel solid is not because anything's actually touching. It's because of electrostatic repulsion. So when you're touching something, what's really happening is that the electrons in your fingers are pushing against the electrons in the other thing. And they're pushing with electricity, with the electrostatic force, electrostatic repulsion,

electromagnetism. So is it like magnets where there's like an electron is negative, an electron is negative, and so you can't push two negatives together? Yeah, it's like that. I mean, it's not magnetism, it's electricity, but it's the same kind of like repulsion, right? And so when you're trying to, when something feels solid is because you have those atoms are packed together and the electrons are on the edges and they're pushing against stuff.

And so the reason why, for example, a neutrino, which is a tiny particle that has no electric charge, can pass through the earth without noticing, is because it doesn't have any electric charge. So it doesn't interact in that way. So the earth is not solid to a neutrino or vice versa. And can it just pass straight through an electron shell? Like, so in the space between where the electrons are, and the proton is, and and the nucleus is it could just go right through that space Yeah, I mean it yeah I mean it can go through a neutrino can go through like a light year of lead with only a tiny chance of interacting with anything

Right there neutrinos going through me right now. Oh, yeah trillions and trillions. Yeah. Yeah, huge. No, you're serious. Yes. I'm being invaded Yeah Trillions and trillions. Yeah, yeah, yeah. Huge number. Are you serious? Yes. I'm being invaded? Yeah, but like you're being penetrated by the trillions. Yeah. I'm the number is just huge. They're coming in and out. They're like exit wounds, the whole thing. So it's like a stream. So most of them are coming from the sun.

So wherever the sun is. So the sun direction is. Yeah. They're coming mostly from that direction and just passing right through you and not noticing and you don't notice. And then passing through the whole earth and then maybe passing through somebody else on the other side. Yeah.

I think in your lifetime, there's a chance like you're likely going to have like one or two neutrino interactions in your body, something like that. It's a very small number. What are those feeling? The rest just pass through. What are those feeling? like that. It's a very small number. The rest just passed through. I think there's a chance it could knock an electron a little bit, but it's not going to be noticeable. I mean, you're going to be hit by other stuff.

Yeah. There are bigger worries. Like you're going to hit by muons and other cosmic rays that are more likely. Sorry? Cosmic rays. Tell me more. Hank, I don't want to listen to you right now. Dr. Mack, what am I going to be hit by? Yeah, you're going to be hit by cosmic rays like high energy electrons and muons and some protons and high energy nuclei from time to time. You'll be hit by other stuff for sure, but not so much energy nodes.

I just smashed by it. I didn't know any of this. Yeah. But not so much in your chinos. I just like smashed by it. I didn't know any of this. Yeah, yeah. And if you go up to like high altitude, you'll get hit by more cosmic rays. So like if you're in a plane or in a spaceship, you're gonna get- Great. That's why I stay near sea level.

Yeah. When I was like standing right underneath the Aurora Borealis, was I getting extra? So I think the whole earth was getting extra. I don't know- Okay. I don't know. I don't know that being able to see the aurora specifically. Because the aurora is like what, I mean, probably a bit like just because like what's happening there is that these charged particles from the sun are smashing into the upper atmosphere

and you know, they're kind of being funneled around by the magnetic field, but they're smashing into stuff in the upper atmosphere and lighting it up. They're exciting those atoms in the upper atmosphere. So you're seeing stuff because there's just way more flux of cosmic rays from this plasma thrown off by the sun. So the fact that there is an aurora happening, yeah, you're probably going to be hit by more stuff at that time. I thought about that actually because some of my friends were going flying during the aurora and some people got some nice views and I was like, are you getting way more cosmic

rays when you go up during that? They're up there now. Yeah. I mean, it definitely messes with some of the navigation equipment for planes, so you have to be a little careful about that. But yeah, I mean, I think it's a little worse, I think. Yeah. Neutrinos. I mean, yet one more reason to stay here on Earth. Yeah. It's such a good planet.

The best planet from the perspective of getting attacked by cosmic rays. It's protecting us so well. That's true. And on Mars, you don't have the magnetic field moving stuff around. You don't have a thick atmosphere to stop some of that stuff. The flux of radiation on Mars is way worse than here. You don't get to live in a nice pretty dome on Mars. You got to live underground. No, you're living under the dirt. Yeah. Yeah. Wow. Okay. But she'd still do it. Yeah.

It's time to transition to the news from Mars and AFC Wimbledon. Mars, of course, Dr. Mac's future home and AFC Wimbledon, home to my heart. I'd like to go first, if I might. Okay. We've signed our first new player of the new season. All right. It's the off season, but we've already signed someone. It's exciting. I don't know how excited to be

because this guy, Matty Stevens, so we've signed a guy named Matty Stevens. He got relegated last year, but he scored 18 goals while being relegated, which is pretty good. What does relegated mean? Like he like was on a team and they kicked them off? No, he was on a team and the team got demoted to the league below.

Gotcha. Their name was forest green rovers and they got demoted to the team, to the league below, but he has signed for us. His name is no longer forest green rovers. They've, they've taken their name away from them. Cause they were still static. No, their name is still forest green rovers. It's just now they're no longer in the football league.

So you can't play as them in FIFA. Oh, gotcha. So anyway, his name is Matty Stevens. He is 5'11". I don't want to get too deep into it, but he has beautiful eyes, beautiful, phenomenally beautiful. You look into his eyes and it feels like the whole universe is looking back at you. It feels like, wow, there's so much complexity within a single individual, it's astonishing. We all contain that. He's also got like a face that makes me think he could definitely beat me up.

But I guess that's probably true of all the soccer players. Not only could he beat you up, Hank, but he is a retired professional boxer. Really? Yeah. I could see it in the shape of his jaw. There's something in the shape of his jaw where it's like that guy knows how to throw a punch, which he literally does. I think that's great

because being a football player is tough. It's not as tough as being a professional boxer. And so I think that he comes at this from an honest place. Also, you got to be a pretty hard worker to be a professional boxer. So I feel really good about the whole situation. I'm excited. We'll see. Yeah. No, he's got kind of a beefy Jamie Tart vibe. He's got a little bit of a Jamie Tart vibe. You know, the guy who plays Jamie Tart is an AFC Wimbledon fan. Yeah. And he likes you. He talks about you. Yeah, yeah, yeah. He's a fan because he was a fan of my FIFA series back in the day. That's very weird. Which I'm thinking about bringing back now that I've got this fancy setup. Yeah, yeah, yeah. He's a fan because he was a fan of my FIFA series back in the day. That's very weird.

Which I'm thinking about bringing back now that I've got this fancy setup. I didn't set up my fancy new setup today. Hank, what's the news from Mars? In Mars news, NASA and the European Space Agency have officially signed an agreement for NASA to provide support for the ExoMars Rosalind Franklin Rover mission.

So NASA is joining ESA inars Rosalind Franklin rover mission. NASA is joining ESA in the Rosalind Franklin rover. It was originally set to launch in 2022, but it involved Roscosmos and ESA ended that partnership for clear reasons. NASA will move into that space now and will be providing elements like the radioisotope heating units. And they're finding a US commercial launch provider for the rover and it's slated to launch now in 2028. And it will and Katie's is going to ride it like a bronco. I was going to say like a motorcycle all the way to Mars. I don't like this idea at all. just all the way to Mars. I don't like this idea at all. I'm just going to tell you. I don't like it. I don't like you going to Mars at all. I don't mind you going to space. As long as you can get there by 2028, because we have a bet.

No. Oh yeah, Hank and I have a bet. We're going to rename the podcast if by January 1st, 2028, there's no humans on Mars. So I'm feeling pretty good right now. I bought into the hype a little too hard back in the early 2000s. As a scientist, what do you think the chances are? So 2028, four years from now, I don't think we're going to have humans on Mars by then. No, unless we invent teleporters. Yeah, because in the best circumstances, it takes like six to nine months to get there. We don't have a launch vehicle yet. Yeah.

No, there's some serious problems. So you have to add that to like, and there's so many, I mean, we don't have time to go into all the reasons why getting to Mars and living there is very, very hard, but it's very, very hard and we have not solved those problems yet. No. Well, I for one hope that we don't solve them anytime soon, lest you go to Mars and live there for the rest of your life. I think it'd be awesome if you were on Mars, Dr. Mack.

I think I would really enjoy it. All right. I mean, I support you 100%. No matter what you want out of this world, I want you to have, but we're not even talking about this world. We're talking about a literally different world. I want you to have everything that you want in this world. That other world I'm not convinced on yet. But what if I have everything I want in this world and then it's time to move on because I've already had everything I want in this world. That's a beautiful idea. It's a beautiful idea.

I don't think it's possible. Nobody's ever stop wanting. We're still getting started. We're still just getting started as a species, as a universe. We've got a long way to go. Dr. Mack, thank you for podding with us today, but more importantly, thank you for teaching us all the history of the universe on Crash Course,

the universe, a new podcast available from Complexly. Hank, it's also a joy to pod with you. Yeah, please go download it right now. You're in your podcast app as you listen to this, so it's very easy to just open it up while I'm saying these words. And you could be doing it right now. And maybe you even are. In fact, you are. Look at you. Look at you go. This podcast is edited by Joseph Tunamadesh. It's produced by Rosianna Halsrohas. Our communications coordinator is Brooke Shotwell. Our editorial assistant is Tabuky Chopravarity. The music you're hearing now and at the beginning of the podcast is by The Great Gunnarolla.

And as they say in our hometown, don't forget to be awesome. Thank you guys so much. This was a lot of fun.