Navigating the Cosmos and Redshift Riddles

Hi, there, Andrew Duncley again with another episode of Space Nuts, and it's good to have your company. This is a Q and A edition. This is where we answer your questions if we can. If we can't, we just pretend to. We've got questions about light and redshift. Today we're also going to talk gas giants, expansion of the galaxy versus or expansion of the universe versus galaxy collisions, and a future of navigation reference points. How are we going to do that? When we start going further and further out, those questions will be answered or they'll be faked. We're not sure yet. Deep fake radio coming up soon on this edition of Space Nuts fifteen seconds. Guidance is in channel ten nine ignition sequence Space Nuts or three two. One Space Nuts. As can I report it? Neils good and. He's here again, like a fly on a piece of meat. Hello Fred, Thanks so do Thanks professor Fred. What's an astronomer at large? Nice to see you. Yeah, that's right, it's nice to see you too. I think I. Have enough digs at Hugh. I thought maybe I. Should just should That's fine. Land a left hook for a change. It always comes back and hits me. Though eventually, so, yeah, I can't take it. I'm tough. Let's let's go straight to our questions. Our first question today, Fred comes from Mario in Melbourne. He likes to go go karting. Hi, Fred and Andrew, hoping you can help explain why if light itself doesn't experience time, how can it redshift? Doesn't red shifting imply it changes somehow, which implies it must have been subject to time. Or is this some sort of relativity witchcraft where we as observers experience time and the red shift, but the photon itself somehow in all states it can be simultaneously or something like that. Yeah, simultaneously or something like that. Appreciate you unscrambling my brain on this one. Still listening from the far start keep up the great show, Mario from Melbourne. I think we've kind of had variations of this question come up in the past. People sort of have trouble differentiating between light and time and what's going on out there. Can you shed some light on this one for it? I'm sorry, I'm completely in the dark about this one. It's a good point though, and so it's made me. You know, it's got the old cogs working to try and work out what's happening. Because that's right. Because light travels at the speed of light to the fastest speed anything could travel through the universe, it does not experience time. A photon of light does not experience time, and yet they change. And you're right, Mario is correct that we do see photons changing because the photons that we are now receiving from distant galaxy, for example, are highly red shifted. They've become ready photons. Now, what that corresponds to is a loss of energy, which results from the expansion of the universe. And so I think I'm right in saying that the photon doesn't notice that. It doesn't know that it's lost energy because it doesn't experience time. So I think you know, in a sense the loss of energy, which by the way, just filters out into the universe. Apparently normally that's where it goes. It's I think that is a property of the observer, the fact that we're observing this thing. The photon, the best of my understanding, doesn't care it arrives at the same time as it left because it doesn't experience time. But it might be surprised that where the place where it arrived at is very different from the place where it left out in terms of the energy balance and what's happening there. I'm not sure whether I'm making much sense here, Mario, but that's my understanding of the situation. Okay, it is a bit complicated. It'd be nice to be a photon if you're doing a long haul flight, because if you didn't experienced time, you wouldn't have to worry about it twenty hour flight to Turkey, for example, or anything like that. Yes, this is weak, yeah all over. Yeah, we hope we unscrambled your brain, Mario, because it is a bit of a scrambling issue. But photons don't experience time, and they don't know that they're losing energy. It's sort of like old people. Yep, yep, go to health. I probably you should say that, though you know. Now look I can vouch for that. I'm starting to. Experience that myself. Yes, thanks, Mario. Let's move on to our next one. This comes from Nugel. Oh friend Andrew, this is Nigel from Brisbane, Australia. I have two questions about our gas giants, Jupiter and Satin. I want to know beneath all that gas. Is there a rocky planet and if so, how big are they in relation to the Earth? Okay, thank you, love the show. Keep up the good work, thanks Nigel. Yeah, look, its. Theory, isn't it. Fred. We don't know for sure what's down deep in those gas giants, but there might be something. Well, you've absolutely answered the question, Andrew. Okay, we'll move on to the next one from Raoul. Nigel's question is you know it's one that many astronomers and plunge your scientists ask because we don't know, we don't know the answer. The modeling suggests that, because of the way we believe planets are formed, that there should be a rocky core underneath all that gas, that it should be quite massive, maybe with a fair degree of a water ice involved with it as well. Although some of the papers that I've read suggest that there might be something called metallic hydrogen at the center of these gas giants. I'm not sure what that means. Probably mean hydrogen in a state where it can conduct electricity. So yeah, so that's it's a question that's really at the forefront of knowledge. So you and me both, Nigel, I wonder what's at the center of these gas giants and how big the central core might be if there is one, which we assume there is. Yeah, I mean guess giants to a certain degree. What could have been stars had their formation happened in a bigger, better way. At what point do they reach in size or structure where they wouldn't have a solid core? Like would a brown dwarf? How does have a solid core? Perhaps, Yeah, that's certainly a brown dwarf would have a core, and it probably wouldn't be solid either, similar to more similar to what the Sun's core we think is like, compared with what a planet's core is like. So brown dwarf has nuclear reactions taking place, but they're low level. Once they're something called deuterium burning, and that doesn't generate anything like the same amount of heat as the hydrogen process that is going on at the center of our sun. So at the center of the Sun, you've got this ball of energy, very very hot, radiating gamma ray photons out which eventually find their way as a visible light out to the surface. The brown dwarf, you've got low level radiation which finds its way to the surface. With a gas giant, though we don't know that's the thing. We really don't know what the core would below. That. The thinking is that that they are cold enough to have a solid core. You know that you're not talking about a ball of energy. But we do know again that there are nuclear actions taking place. For example, in the core of Jupiter Jupiter radio is at one point eight times more heat than it receives from the salt that's coming from maybe uranium fission or something like that happening down there in its interior. Wow, do they have a theory if Jupiter has a core? Do they have a theory on how big it is compared worth? Probably? But look, I'm going to take as take a punt and say yes, people probably do think it is about the size of Earth. I'm sure that kind of suggestion before. I just remember Jupiter's about eleven times the diamature of Earth. Yeah. Wow, all right, jury is still out, Nigel, but it maybe could be done. Oh type of scenario. Thanks for the question. Sorry, nothing to do with us, nothing to see here. This is space Sandred Duntley with Fred Watson, Professor Astronomer at Large. Great guy, Now let's take a little break from the show to tell you about our sponsor nord VPN. Now, not so long. Ago, I did a bit of a speed test just add hop speed test. Didn't plan it, just went ahead and did it on the spot, to prove that you do not lose very much speed using nord vpn on your desktop computer or your laptop for that matter. I thought i'd tested on my mobile device, which I haven't done in recent times. So I've got my phone here, I've got the speed test icon going, so I'll do a speed test without using NordVPN. So here we go, and it is connecting and doing what it does. Boom, Okay, there's a well. It peaked at one hundred and thirty five, but it's hanging around the one point fifteen one sixteen mark. So I'm going to close that they're not going to connect NordVPN to my phone, and we are ready to go via NordVPN this time, and I'll hit go and we'll see what happens. So this is going via Central Australia, and I'm still achieving speeds of about seventy to eighty megabits per second. I am losing a bit, but it's not a lot. That's still really good speeds on a mobile network, the upload speed is actually faster. My upload speed is pushing up towards ten megabits per second now it's just hitting eleven. So with NordVPN, I lose a bit on the download, but I gain almost double on the upload, which is extraordinary. Now they've been our sponsor for quite some time. I use all their products I've signed up. There's a special URL if you're interested in looking at NordVPN as a space nuts listener. To get the best discount off your NordVPN plan, go to NordVPN dot com slash space nuts. Our link will also give you four extra months on the two year plan. There's no risk with Nord's thirty day money back guarantee. And I'll add the link to the show notes. And they backed their products, not just the high speed VPN, but the malware protection, the tracker ad blocker, cross platform password manager and that's my favorite thing in the world, the data breach scanner, and a terabyte of cloud storage. Depending on which plan you get, you can combine all those things. So NordVPN dot com slash space nuts is where you go and check out the deal today. You won't regret signing up with nord VPN. Now back to the show. Three Space Nuts. Okay, our next question, Fred comes from Raoul. Hi, guys, Raoul from California here and a big Chelsea fan. I know you were talking about American football, but I do like europeanotball. Had a question for you. If the universe is ever expanding from the Big Bang, then all the galaxies will be moving apart from each other. But I recall seeing on a show that galaxies could one day collide. Does that mean that the universe is stopping its expansion or slowing its expansion, allowing the gravity of galaxies to then collide. And if that is the case, will the universe one day stop expanding and start to contract upon whatever the hugest big black hole in the middle of the universe really is. Thanks a lot, you guys do great love listening to it. Beat the show. I love what you did, right, Thank you, David Chelsea. Oh sorry, yeah, David, next roll roll thanks for that. Yes, Chelsea fan, but yeah, we'll forgive you for that. I'm a Liverpool fan myself. Do you follow English Premier League? Most League slightly? Yeah? Only you know some of the bigger teams. I've was interested in what they're doing. I've got a son in law and a grand couple of grandsons who are absolutely mad Manchester United freaks, and you know, various various other football teams. I never really got heavily into football. I can never remember which I was supposed to be kicking the balls and it wasn't nice team really, But yeah, that takes an interest. Yeah, I played soccer for ten years, never won a thing. I didn't even win the Raffle anyway. Raoul's asking about the universe and his expansion versus galaxy collisions basically, and is the expansion slowing or stopping? And is that why galaxies are going to crash into each other? Is it all going to sort of fall back into a giant black hole in the middle. We've had variations of questions like this over the years. It's one that always spawns a lot of interest. It does, doesn't it. And there are actually two things going on here. I think in rolls question because it's quite right that some galaxies do collide with each other, but in fact we are in poor position for a collision with Andromeda that might already be happening. In fact, yeah, in fact, yeah, we talked about it the other day. They're actually sort of you know, tickling their fingertips at the moment because of their giant gas balls. That's been revealed. Indeed. So and so why are they colliding if the universe is expanding? Because both those statements are true. The universe is expanding, and the two galaxies are colliding. And that's because at the on the scale of the distance between Us and Andromeda, which is two point five million light years, the expansion of the universe is negligible more or less the universe. The universe is expanding, but over a small distance like that, what becomes the dominant force is gravity, and the gravity, the gravitational pull between the Milky Way and Andromeda, easily enough to overcome the fact that they're being pulled apart much more gently by the expansion of the universe. So, and that's we give a term. We've got a name for the individual motions of galaxies kind of superimposed on the expansion of the universe. We call it their peculiar emotions. And it's so the peculiar motion of Milky Way relative to Andromeda. Is they colliding together and they will collide, whereas the expansion of the universe is trying to pull them apart, but at a much much slower rate, if I can put it that way. It's only when you look on the big scales that you see the real effects of the expansion of the universe, things that are billions of light years away from us rather than just a couple of million, And basically Raoul's right. Until nineteen ninety eight, we used to think that eventually the gravitational pull of everything in the universe would slow down the expansion and the universe would indeed collapse on itself in what we always call Andrew. The ganeb GiB, the gonab. GiB exactly, big bang, that's right, Brian branch mates praise the gonnab GiB. We used to think often called the big crunch as well. That was the thinking. But it was when Brian Schmitz Ant his colleagues and other colleagues in the United States, when they discovered the accelerated expansion of the universe that possible the possibility of the gadab GiB was thrown out of the window. Because the universe is, as far as we know, going to expand forever and there isn't enough stuff in it for its gravitational pull to halt the expansion. And part of that is because we think that space itself has an energy we call it dark energy, and the more space you have, the more energy you've got, and that energy is trying to push things apart, to push the universe into ever ever faster expansion. So, yes, it looks as though that big crunch scenario has gone out the window. But it was very popular in the nineteen seventies and eighties. So what's the opposite to a big crunch? It's a Hagner gibnurk. Yes, that sounds right. Yeah, someone's going to ask you again because we've had the question before. But you know, if the. Universe keeps expanding and it's filling with dark energy, where where's the energy coming from? You know, wouldn't have that has that fueling itself? We don't know. We all comes out of space. Yeah, it comes from somewhere. Yeah, people say I was coming from a dark matter, but when they're not related, they're just badly named. Yes, that's correct. Maybe it's coming from outside. You know, if there's multiverses or that would be something, wouldn't it. We should just go and have a look. Simple. That's a good idea, same voyage that. Well, it's on its way. We just have to sit here and twiddle our thumbs and just wait a little while, and then we'll know if the batteries don't run out. Uh. Did we finish with Raoul? I think so yeah, Yes, all the best Raoul, and I hope Chelsea doesn't win as much as Liverpool. Let's go to our final question, and this one comes from this is David. Wow, what a coincidence. Hi love your podcast. I live in the lovely dark city of Tucson. That will be the Arizona variety. I imagine my question my question. I assume astronomers use the sun as a center of reference, but what about the future when we want to travel somewhere else? Everything is moving and it's a no body system. It's hard to know exactly where anything is going to be if you wait long enough, How will you tell our colony on proximate sentry where to go or where to look when it takes four point two years for them to get the message? That's from David. I like this question. It's a long term future problem when we're living in other parts of the of the galaxy outside our own solar system. We've we've made the giant leap and ended up on one of those perfectly normal planets around the Alpha Centauri system, and we want to come back. How do we find how do we find our way back? I mean, we can find our way there, so I assume we can find our way back. M Mathematics would be my answer to this one. Well, it is, it's it's a it's a good question actually, and it has a real significance to it because we we need we already need reference points like that for things like GPS, you know, satellite navigation systems, space space navigator. Even in the small distances within our solar system, you need fixed reference points. And what we use are the things on the sky that move least and that bright, and they are quasars. So quasars are very bright sources, but there are very great distances, so distant that nothing we could ever do in terms of our movement would change their positions on the sky. And so quasars have formed the fundamental reference system that's used in astronomy actually as well as for navigation. We use them to set up basically reference systems for measuring galaxy position, star positions, things of that sort. You use something that's not going to move, and the quasars don't move because they're so far away. So it's already there, David. And hopefully when you leave Tucson and head out towards Alpha Centauri, you won't need to have any worries that you'll lose your way home. You'll find your way. But yes, and don't ignore the sign that says next fuel stop two bill in kilometers. You really don't want to skip that one because it's a long way to the toilet, let's face it. Yeah, yeah, all right, I didn't realize it'd be that easy, Fay. It's good to know. Yep. We just got to we've just got to perfect the engines that enable us to travel far distance is in a bit of a hurry. That's that's probably the bigger challenge than the navigation. Thanks David. Great question, and if you have a question please send it into us fire our website space nuts dot io. You thought I was going to say space nuts podcast dot com, didn't you. Yes, well that counts to you can use both. They all end up in the same place, and you can send us a text or audio question just by clicking on the AMA tab. And if you've got a device with a microphone, you're all set down. Forget to tell us who you are, where you're from, and don't forget to leave your reviews on whatever platform you use to listen to us and social media, follow us, like us, subscribe wherever you are. We'd love you to make our little family a little bit bigger. And don't forget about the Space Nuts podcast group on Facebook. It's always growing. It's growing like a like a blob of gas in a nebula or whatever it is, and will Yeah. It's where you can sort of chat with like minded people who follow Space Nuts, talk to each other, ask each other questions, share your astronomical photographs and stories. It's growing at a rate of knots. It is bread. And thank you for your company today, friend, Thanks for tolerating my stupidity and answering all those questions. That's all right, I can live with Andrew, No, we'll continue to do so, keep up the good work. It's always great to talk. Thanks a lot, We'll see you soon. Professor Fred Watson, Astronomer at Large, and the Not Professor Hugh. Thank you to him for helping out Not today and we'll see you very soon. Andrew Dunkley signing off, We'll catch you on the very next episode of Space Nuts. Bye Byepacenuts. You'll be listening to the Space Nuts podcast available at Apple Podcasts, Spotify, iHeart Radio, or your favorite podcast player. You can also stream on demand at bites dot com. This has been another quality podcast production from nights dot com.