Origins of Motion and Galactic Travel

Hello and welcome to another bonus episode of the Super Massive podcast from the Royal Astronomical Society. With me, science journalist Izzy Clark, astrophysicist, Dr. Becky Smithers, and the Society's deputy director , Dr. Robert Massey. Who have you all been up to you recently? Not much. You know, not like the moment for me . No, I'm still on my I got married high . I presume when this episode comes out, I won't even be in the country 'cause I'll be like, I'm on my honeymoon bye . Yeah, rightly so man. Deserved, you're gonna have such a good time. What have you been up to? Me, while I'm doing my thing, you know, doing lots of astronomy. I'm actually because I've got I've got to have some surgery later this year for Crohn's disease. I'm not going to be able to go to Spain to see the eclipse, which is annoying. So I know, I know, so anyway, what can I say, cancel the accommodation , but I am looking forward to seeing the UK . Yeah, it's great it's a great view here. It's just not the same as totality as we always say. So but I'll still look forward to that. There'll still be lots of people here enjoying the view as well. Yeah. Look back that day. What is it the sixteenth of August, something like that? August? Yeah, midwest. Yeah. Well, I have some exciting news. Oh yeah. I've bought a sea star fifteenth. Oh wow. I'm doing it. I've wanted it for well everyone, whoever's been a long time listener, has just heard me talk every year I go maybe, maybe I will. And I went fully freelance. I'm full time freelance now and I went, I'm just gonna treat myself to a really nice present nice . No, I just wanted a little tree and you know, I said at the beginning of the year, be a better astronomer. So this is my step into becoming a better, bad astronomer. I'm so glad you brought it. Can you put some pictures of you using it for? You bet . Absolutely. And put these together, you know, guys. Be cause that's the super massive club forum. If you're not there, you square. Please be kind and tell me what I'm doing wrong. Okay, thanks. I've got you know, I've got it. I've been lent to dwarf too, right? And it's fairly old by the space artist Sally Russell. She's got a better one now. She led me this twelve too after . I've just about taken a picture of the sun with it. I am still definitely learning. The app looks to me like I'm looking at it thinking, people do these things. I need to learn all this. They're amazingly powerful. They take pictures of galaxies four billion light years away. You know, how does it do that? This tiny piece? Oh my gosh, I feel like there's no pressure, no pressure. No, but I feel like we're creating a new discussion channel for the forum that is just the bad astronomers club where people can post their questions of like this has happened. How do I figure out ? I was going to say and they'll be us asking the questions. Yeah, I'll be like number one poster on there . Okay , so let's go on to some questions. Becky, listener, Paul Newton has sent us an email. It says, Hi Team, thanks for all you do. Can you predict what might happen if two diamond core stars collided. Are we talking cosmic billiards or would the extra energy input cause something to happen ? Well, I think what you're talking about with diamond core stars is like white dwarf stars. So the thing that's going to be left behind when the sun eventually runs out of fuel and novas and dies and leaves behind mostly carbon core which, yes, you could describe as a diamond because it would be crystallized because of the heat. So I think that's what you're talking about. So if two white dwarf stars collided , it would be I mean if you had a direct head on head on collision, which would be very rare, right? But technically possible , then yes maybe you would have a cosmic like pool ball thing cosmic billions like you've described, but the more like ly collision of two white dwarf stars is going to be the fact that they were like a binary star pair. So two stars in orbit around each other , which both you know died and ended up as white dwarfs . So imagine, you know, the sun being on its own is not the normal. Binary stars are very, very common. So you can imagine two suns in orbit around each other and they both ended up as two white dwarfs by the end . Those can slowly inspire together and eventually collide . And if that happens, then they don't just collide they do merge together. We've seen the likes of like two neutron stars collide before with LIGO and we've perhaps seen the remnants of a white dwarf merger . It's thought that maybe even some type one A supernovas are actually white dwarf mergers as well . So it's not a rare thing necessarily . What happens afterwards is really depends on how big the two white dwarfs are that merge and it's whether you're over what's known as the Chandra Secaar limit, which is like the limit for how big a white dwarf can be and how much how big it can be before that crystalline structure of that sort of diamond core thing that you're talking about is overwhelmed by the mass essentially. And if that happens, then you're going to end up with a neutron star, which is neutrons in a very tight crystalline structure as tightly packed as they can go. So that's what would happen in terms of the collision and that would completely get rid of the diamond aspect of it as well. You're more likely to have this sort of like diamonds and not forever then Becky. Indeed . Diamonds are not forever, especially if they merge together in White Dwarf Stars 'cause you just get run away fusion taking you to like nickel cobalt and then probably just as glamorous . Cobalt doesn't really cast it, does it? You know, Iron Engagement Rings . Two weeks their own . Robert, Clayne Lynch on Instagram says, Hi, I have a question about the Moon, which maybe you guys will be able to help with. It also links with your episode on Rogue Space Objects , given that the Moon is receding from Earth at a rate, which I've inconveniently forgotten. Is there a point at which the moon will no longer be tidally locked with the Earth? Love the podcast . Thank you, Kane for the love and I've realized I've inconveniently forgotten the second part of your question, but I've written an answer anyway. So it's indeed receding from the earth. The moon is moving away about three point eight centimeters a year slightly spritely, but not really rushing . And we know this because we fire terrestrial lasers that are at the moon, they're based around the world. You fire a powerful enough laser and it hits one of these six reflectors that were left behind by Apollo's eleven, fourteen and fifteen, the Soviet Lunicod Rovers in the both of those in the seventies, sixties and seventies , and the Indrian Indian Chandrian three mission. And if you fire it, knowing the speed of light, you time how long it takes to go to the Moon aback and from that you can work out that the Moon is indeed slowly moving away from the Earth. Now it's moving away by gaining energy from the slowing down the rotation of the Earth because our day increases by about two point three milliseconds a century. So a tiny tiny change is enough that you get a leap second every so often, although we haven't had those for quite a long time . And in theory, the Earth would definitely become tidally blocked to the moon in about fifty billion years time, but the problem is that the sun won't last that long . So the sun's slowly getting brighter, two billion years time Earth won't be habitable because of that. But in about seven and a half billion years time, the Earth Moon system will be further from the sun because the mass of the sun because of n auclear fusion will have gone down, the gravitational force will weaken . However, the sun will become a red giant, swell up enormously, and the earth and moon by every expectation will be within the Sun's atmosphere. So I think before the Moon could ever drift so far away that it was no longer in orbit, which I think is the point at which the tidal locking would probably no longer happen , both worlds will be consumed by the Sun's atmosphere. So that's that. So sadly we don't get to see that nor do we get the Earth to tidally block the moon because there just isn't enough time. But if you want an example of where two worlds are tidally blocked and I don't know they're never going to get consumed by the sun. Then look at Pluto and Sharon , Sharon is big compared with Pluto, about half the size, and they're even closer to being a double dwarf planet at least than we are with the Earth and Moon. So sadly that the sun wins in this case and the Earth and Moon aren't gonna go to that state. I still hear that though, unlike the Moon and Earth our BFFs is facing. Yeah, they are to the very end. To the very end of the end. That's all I took from that. Thank you for good to know. My ride will die . And Becky, can you help give Sam Isaacs a headache because Hi from British Columbia, Canada. Oh , I know. I'm so jealous. Tell us what it's like there, sir. Tell us about the sky. Thank you for tell us about the Aurora. They say thank you so much for your wonderful podcast and accessibility to listen to questions. It's very much appreciated . Here's a simple question to ask. I'm not sure if the answer will be simple. Why is there motion in the universe? Of course, if there wasn't any motion, I wouldn't be here to ask this question and you wouldn't be here to answer it. But presumably at some initial point and before there was matter there was no motion. So how did motion and associated velocity and acceler ation come into existence. I presume there was some process converting pure energy into something , but why did that require there to be motion and is motion an inherent property of time. Thanks for your time and for my opportunity to have my head hurt a bit. It's a great question, Sam, honestly, it's fantastic. I think at the very root, if we were going to go to the very root of it, we get'd to quantum physics and we'd just be like because they're own . But I think perhaps an easier way to think about it would be to think of just a thermal motion as it's called if you think about a gas that has a certain temperature that is inherent energy to that gas, so therefore the molecule's moving. And if something is absolute zero temperature wise, then yes, there would technically be no movement . So coming back to your idea of, you know, you said before there was matter, was there no motion? It comes back to this thing, the fact that our physics breaks down at ten to the minus thirty six seconds, you know, into the universe's lifetime before that, we don't really know what was going on . It doesn't really make sense to ask was there before a big bang because the Big Bang created space and time. So the concept of before didn't exist, you know? So it's one of those strange things, but there was obviously a huge amount of energy involved in those first initial seconds of the universe. We know that through inflation that has to have happened to give us the universe around us, at least that's our best theory of it anyway. Has to be lots of energy. So there's energy there's therefore thermal energy in any particles that were created and they will have random thermal motion, just like little jumps from the fact that they have some temperature and some energy . If that's the case, then as soon as you have random jumps, there are random jumps that could take you closer to other particles and then gravity is like, Oh, I'll just come together. You know, they'll stick together . And then so on and so on in a snowball until you start to get bigger objects forming , but bigger objects that in herit all of the energy from the things that formed them . And from the fact that if there was gravity starting to pull in things from nearby that will have also then added motion into those particles as well. And so everything that clumps together, every object that you end up with its motion is inherited from everything that went into making it and anything that's collided with it and things like that . So for the fact that there is just inherent energy, which, again, if you're going to go from a lower perspective, it goes into the quantum things of like probabilistic nature of things . That is why there's motion motion in the ocean. Okay , thank you, Becky. I'm so glad you tackled that because as soon as I saw the line, is motion an inherent property of time. I was like, I didn't even think about that either. If we're thinking about motion as an inherit property of time and we think about time and we think about it in terms of entropy in the universe, right? The second law of thermodynamics is that entropy must decrease. Things must gets wait increase. No enterprise must increase. What is that entropy? Yeah, is that entropy must increase and that things must get more disorganized with time ? That's the only sort of with time law we really have , but if you think about disorganization it is probably motion but more chaotic motion . So there is no inherent like motion must come with time but, similarly, right? Because if we have this law of entropy, then yes, that kind of is in the same way. Yep , love it. Really love it. I have a headache too, but I love it. Okay, that cured my headache and told me And Robert, here's a final question from Craig Hollingworth. Hi, I love the pod and mentioned before my little connection to being in Chapel Hill where the Apollo astronauts trained in celestial navigation. My question today is based on listening to the Extinct Zoo, a podcast I like a lot. I hope it's a good one but not as good as ours. Anyway , the narrator says the dinosaurs lived so long ago that technically they lived on the other side of the galaxy. I found that fascinating. He noted that the Earth and solar system is always flying through space like a bullet and since the time of the dinosaurs has travelled through different galactic neighbourhoods within the Milky Way and since the time of the dinosaurs has traveled through different galactic neighborhoods within the Milky Way. It's very interesting and I wondered what you thought , is that true? Love ya, mean it, Craig. Thank you, Craig for the love. We love you back. But okay, so to turn to your question, they are, yeah, the solar system and sun are indeed moving through space actually much faster than a bullet, really, very, very quickly when you got tens of glimpses a second. But to turn to your question, so the solar system completes an orbit around the Milky Way galaxy. We're thinking about between two hundred twenty five and two hundred fifty million years, so quite a long time, but that does mean there's been enough time for it to go around many times since the solar system was formed . But if you look at when the dinosaurs were ran, if you take that as say the start of the Triassic Geological Era, which is two hundred fifty million years ago then when dinosaurs first emerged, our sun was in more or less the same place . But then the middle geassic, the dinosaurs around for a very long time, one hundred sixty five million years ago, it'd be a long way around its orbit and by the middle of the cre , so a hundred million years before the present day then the sun was definitely on the opposite side of the galaxy. Now one complication when you think about this is that all the stars around us are moving at slightly different rates. So even if you look ated the sky in say one hundred thousand years time, yet alone a million years time, it would look completely unlike the way it does today. You'd still have, I guess you'd still have a Milky Way, you'd still have the same kind of distribution of stars, I think there'd be bright ones and fain ones and probably in similar numbers, but the constellations would be completely unrecognizable . So we have to think about your question. We also have no idea what sky the dinosaurs saw. You know, it would have been something not recognizable, similar types of stars in the sky, but none of the constellations we're familiar with would be there. It would just be very, very different to the sky we see it above hides today . That's really cool. That also question reminded me of I was listening to the Rest is science podcast with Hannah Fryer and Michael from VSOS, which I 'm loving by the way, if anyone else is. They were talking about like how you prove it was like in the episode about how you prove that you are a time traveller if you find yourself accidentally traveling through time either to the past or the future. It was very interesting. Love up. So good. But it was also talking about how if you did travel back to the time of the dinosaurs millions of years ago on Earth , you actually wouldn't be able to survive because there'd be nothing you could eat . Not only would you be on the other side of the galaxy, you'd also be like, I can't really eat any of the plants because they're all carcinogenic. And the dinosaurs eat all of the plants, and the other dinosaurs eat the plants, so everything in the food chain. It is toxic poisonous and toxic to me . I need to be on the other side of the galaxy, so . Oh my gosh, it's one of those questions where you pull on the thread and you're like, Oh my goodness . Everything's unraveling. And also like with this as well, if you think about it, when you know the Earth would be over the other side of the galaxy, if you were going to time travel, you would have to space and time travel . Exactly . Because wherever you were going . Otherwise, you end up in the middle of space. Yeah. It's true. Well, yeah. That's it. Exactly. So don't just invent a time machine, invent a space and time machine , please , someone . I'll work on it. Don't worry. Yeah, you've got your C star now Now I want to go over there. I didn't know it had that built in feature. Wow. They've done that. It's the next recording live broadcast from yeah. Oh gosh . Wow, I think that's all the questions and nonsense that we have time for today. So do keep your questions coming. We love them . They're just so fun . You can email podcast at RS dot ac. UK, find us in Instagram at Supermassive Pod or join the Supermassive Club. It's a lovely little space. Spacelight we did the there we go and there are no adverts there as well. Lovely times but also you can post on the forum and we chit chat about how I will become a better astronomer at some point . Hey, everything, you know, with time . You know, we learn on the job all the time, is he? Every day's the school day. Every day's school day. We'll be back alone in a few weeks time with an episode all about neutrinos, which I'm very excited about I presume we're talking about the picture that was taken through the earth at some point is because that's one of my favorite Nutrino pictures. Yeah . It was taken at night of the sun. How did they do it? Until next time though, everybody , happy stargazing