What Happens When Galaxies Collide?

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Speaker 1: Hey, Daniel, what keeps you up at night? Oh? I worry about a lot of things. Financial crises, my kids growing up to be just like me, all sorts of stuff. I worry about that too for them. You worry about my kids growing up to be just like me. We can't have more of him in the world, Okay, But like on a galactic scale, on a universe scale, what's something we should be concerned about. Well, we do have a lot of things look forward to in terms of our galaxy. If we survived the Sun exploding and the waters the Earth boiling off, then we have something pretty dramatic to look forward to, which is that our galaxy, the Milky Way, is going to collide with their nearest neighbor and Dromeda. Meaning right now, there's an entire galaxy Drameda heading towards us at this very moment. That's right. It's like somebody shot it at us with a slingshot and it's zooming right towards us, and it's going to hit us smack on him. And I'm Daniel, and this is our podcast. Daniel and Jorge explained the universe on the episode. Today, we're going to talk about what will happen when galaxies collide. Is this something we should all be worrying about our packing our bags, about building our underground shelters or are we all screwed? Or is it just going to be like a big nothing? How much should I pack? You should definitely be stalking lentils no matter what. Lentils are a good investment for any of these end of the world. Not just beans, no, no, lentils. I mean lentils are kind of lego for a galactic emergency. That's the that's the one to go with. Yeah, absolutely, I would. I would invest in lentils heavily. And it's not just because I happened to purchase lentils just before we recorded this podcast and I'm trying to drum up the lentil futures, you know. I'm I'm sincerely worried about our listeners, and I encourage you all to go out there in stockpi lentils. Well that's a whole hill of beans worth of advice right there, that's right. And so this is the question and today's podcast, what will happen when our galaxy, the Milky Way, collides with the neighboring galaxy? And this question I love not just because it's huge and dramatic and galactic and all this sort of stuff, but because it was suggested by one of our listeners. That's right. It's Blake from Australia who listens to this podcast on her commute to work every day. That's right. And she didn't tell us what she uses to commute. Maybe she rides in a beautiful pickup truck, maybe she's in the back of a limo, maybe rides kangaroo who knows, that's right, with a really nice sound system. Yeah, but she has some interesting feedback for us about our podcast. Right, what did she say? Yeah, she said that she likes listening to me explain things, but she also likes when you interrupted me. She said that often you interrupt me just the same moment when she has a question and you pose the same question that was bouncing around in her head that she was shouting at her limo sound system or kangaroo speakers or whatever it is she us going to listen to. And so I was glad for that, because you know, I like when you interrupt me. Also it breaks the flow and it keeps me from just droning on and on and on. So Thank you Blake for suggesting this topic, and thank you Orge for occasionally interrupting. Yeah, no, I'm happy to be rude. It seems to come naturally. Yeah, yeah, And so that's the topic of today's podcast, And we thought first before we dove into it, we would walk around like we usually do and ask people, are you worried about a galactic collision? What do you think will happen when our galaxy collides with a neighboring galaxy? So put that image in your mind to giant galaxies, full stars running into each other. What do you think is going to happen? Here's what people had to say, big explosion. We'd probably all die. It is going to be mostly nothing because of all the empty space around the world, although there will be some crushes and so on in the way. Okay, probably somewhere between a glacial, slow event that we won't even notice and nothing at all. Maybe leaning towards nothing at all. I think it would probably be a big explosion with something pretty crazy happening. All right, That was a little anti climatic. People seem to have very low expectations of this event. What do you mean It seems like half of the people are like it's gonna be nothing, and the other half of like big explosions, we're all gonna die. Well, why do you why do you think Blake asked this question? Do you think there's something she's concerned about or is something she's curious about? You know? I think Blake is probably deciding whether or not to stock up on lentils. You know, Um, she's probably right now, story she asked. I think it's part of just trying to be a sort of a citizen of the larger universe, you know, wondering where we stand and trying to think bigger than just our planet, you know, because there's so much going on out there, it's so easy to just walk around on the surfaces planet never really look up and remember that there is an enormous amount of stuff happening out there, And then you wonder like, well, how is that relevant to me? And is he going to ruin my life? Or can I go on ignoring it? Um? So, I think maybe she was just sort of thinking into the deep future and wondering like, how long can this whole ridiculous, beautiful thing we call life on Earth go on? Right? Is it going to change from how it is now, right, Yeah, exactly do I need to change the way I live? Does it affect any decision making? On the other hand, it could be that Blake, like many people, is just a thinker and likes to think about these scenarios, and she probably heard that the Milky Way will collide with Andromeda and wonder like, what's that going to be? Like? You know this this this is the other side of me that likes to smash stuff together. I mean, I'm a particle physicist, but then we have the whole universe to play with, right, and so you might wonder, like what happens when planets collide, what happens when solarcisms? Like oh my gosh, what if we could build a galaxy collider and shoot them against each other and smash them into each other? Right, So it just comes out of like a curiosity to see stuff break by smashing it together. Yeah, well, let's let's take it step back and just kind of think about why even galaxies would collect, Like is this a relevant question that is something that happens a lot galaxies colliding, or is it something that's incredibly rare. It turns out galaxies colliding happens all the time. It's like a totally natural thing. And our galaxy. Yeah, not only will our galaxy collide with and John Day in a few billion years, it's currently colliding with other smaller galaxies. That what Yeah, we're in a collision right now. Yeah, that's right. And remember that the galactic time scales are very different. You know, the galaxy takes about two hundred million years just to rotate once, to go around once. Yeah, so one galactic year is two hundred million earth years. But it looks so swirly. It looks you know, you know what I mean, Like it looks like it's in motion, but it's actually it is. It is in motion, it's just very slow, right, And so all these things are dancing around each other and sometimes they bump into each other. And the thing I think is amazing is that, you know, until like a hundred years ago, we didn't even know there were other galaxies. Like we looked up at the night sky and we saw stars, and we thought, oh, there's just stars that go on forever. At the universe is just filled with stars. The universe is just like a giant MESSI pinpoints, right, just stars. Yeah, yeah, like somebody had scattered stars across the cosmos, right, And it was Hubble, the guy for whom the telescope and the constant are named. He's the guy who figured out, oh, some of those things that are really far out there are not stars. There are other galaxies. Right, So there's the universe is filled with other galaxies. And of course there are more galaxies than stars, and and then each galaxy, of course, contains hundreds of billions of stars, and so the numbers pretty quickly blow your head up before you can understand them. But the point I wanted to make was that we didn't realize there were galaxies until recently, and now we're realizing that galaxies are in motion relative to each other, and they're moving. Like the these galaxies that we see out there in the sky, they're not just like hanging there in space never to change, right, They are moving their dynamic things, and they're constantly in motion, and they have huge gravitational attraction. Well, let's break it down. What exactly is a galaxy? I mean, I know it's like kind of like a collection of stars, but you know what, why do stars clump together like that? First of all? And what makes a galaxy special? Like, why is it more than just a clump of stars. Well, what makes our galaxy special is that you're in it. Horse. There's no other galaxy that features such a good looking, funny cartoonists, meet me and lentils. We make it, make it habitable, right, Okay, so what's the recipe for a galaxy? Right? Well, the thing that the galaxies have the most of, remember, is dark matter. In general, there's about five times as much dark matter as there is any other kind of matter, you know, the stuff that makes up gas and dustin stars and people and cartoonists and and and ice cream. So it's mostly dark matter. So that's the stuff we can't see your touch. I mean, we did a whole podcast episode on dark matter, but it just in case somebody didn't listen to it. Um, it's like this weird invisible dark gravity thing that's hanging out every galaxy has, that's right. Yeah, we call it dark and matter because we can't see it. So it's dark and we know it gives gravity, so therefore it's matter and the crazy things that until you know, a few decades ago, we didn't even know it existed. And now we know that galaxies are mostly made up of this stuff. Right. So number one ingredient when you want to make a galaxy is you have to have dark matter. It's like five times more than the stars, right, yeah, exactly, Like a galaxy is basically a clump of dark matter with a few sprinkles of stars in it. That's right. Yeah. If a galaxy was a cupcake, right, the dark matter would be the chocolate cake, and you know there everything else would be the frosting and the sprinkles. The gas and the dust would be the frosting. The stars would be the sprinkles on top. Oh I see, Okay, that's kind of the right proportions. Yeah, something like that. Um, So you start with big blob of dark matter and that's most of it, and then after that you have huge amounts of gas and dust, right, And that's the stuff that's left over from the Big Bang or left over from stars exploding, and those the ingredients you need to make planets and stars and all sorts of stuff that you're familiar with, right. And so you have dark matter, you have gas, you have dust, you have planets and stars and black holes right, Like there's just a little black hole sprinkled throughout throughout probably, But there's a huge giant black hole at the center of every galaxy. That's right. I can't believe I forgot the black hole. The black hole at the center of almost every galaxy is huge. It's like, you know, millions of solar masses and it's sitting there at the center of the black hole, and it's it's got a lot of stuff to it also, right, it carries a lot of mass and so it contributes. So that's what a galaxy is. And you know, a galaxy couldn't really form without all those elements, Like you couldn't really have a galaxy without dark matter because dark matter provides the gravitational attraction to suck all this stuff together. You know, they do these simulations of the universe. They say, what would the universe look like if you never had dark matter in it? And it would take a lot longer for galaxies to form because dark matter has pulled all this stuff together. It's like it's made a you know, like a well in the rubber sheet of the universe, so everything rolls together more closely. Okay, so that's a that's a galaxy. It's a black hole surrounded by dark matter and sprinkles of stars and gas and dust and lintels and lintels exactly yes, And so they're not just hanging out in space. They're moving around. That's right there. Each one is spinning, right, which is why you see a lot of them having these these spiral features. Each one is spinning, and then they're also moving around each other. They have gravity and they're moving around each other, and they have these Each galaxy is a member of a cluster of galaxies, and so these guys are orbiting the center of the cluster. And then the clusters are members of superclusters. So these things have a lot of gravitational interactions everywhere. It's like a system of galaxy. They all interact with each other, and they all spin around their common center of mass exactly right, And they're all spinning around that center. So it's sort of like a big slow motion tornado. Right you looked at it. If you looked at it really really slow, you're like, oh, nothing's really moving. I mean, I guess a little bit, but you you you watch it at natural speed of tornado, and obviously it's going really fast, and so a galaxy is that's sort of that same way. The gather system of galaxies is sort of that same way, but they're all moving around each other and then occasionally, you know, they bump into each other. Wow, that's so weird to think that gravity works the way like we are, you know, moving around the center of the Earth. The Earth is moving around our solar system, around the center of gravity, which is mostly the Sun, but the Sun is also we were moving around the center of gravity of the galaxy, and the galaxy is also moving around the center of gravity of its cluster of galaxies. That's right, Yeah, and on and on and on like a bunch of nested Russian dolls, you know, until you get to the biggest structures in the universe, you know, which are the superclusters, and then the filaments of superclusters, and beyond that, we don't know anything about whether there are bigger and bigger structures. That's as far as we've seen. So we're moving around and sometimes these two two galaxies can just run into each other. In the giant, vastness of space, all these moving galaxies can sometimes cross pass right. Yeah. And there's another thing I want to say about that before we talk about what actually happens, which is that it's incredible to me that gravity is the force that's dominant on these scales, right, Like, that's the thing that's controlling how galaxies form and how they dance around each other, and that's pulling them all the way through the universe and forming these crazy structures. It's all gravity, right. But gravity is the weakest force of nature. It's weaker than electromagnetism, it's weaker than any of the nuclear forces. It's pathetically weak, but it's the only one that operates on these huge scales, and it can't be balanced out. And so because it's only an attractive force, there's no repulsive version of it. And so that's why, like on these huge scales, gravity is the thing that dominates. Gravity determines the structure the Solar system, the structure the galaxy, the structure of the clusters. Gravity sort of winds in the end. It's like, you know, revenge of the nerd forces, Right, It's the weakest force in the end controls the universe. It's like slow and steady wins the race. It's the turtle of forces. Yeah, Anyway, we need to do a whole other podcast on why gravity is so weird and weak and whatever, and we're into that. Okay, so we have a cult clusters and galaxies are moving around space and sometimes they collide. So yeah, let's talk about what actually happens when two of these things collide. But first let's take a quick break. All right. So we're sitting in a galaxy and we are moving inside of this galaxy, and this galaxy is moving in space. But there's another galaxy nearby called the Andromeda galaxy, and it's kind of an interset course with us, right, like we're going to run into it in about four and a half billion years. Yeah, not kind of. They've measured it. They can measure the velocity of Andromeda relative to us, and they can see that it's getting closer and closer every year, and they can also measure the lateral velocity, like is it going to shoot by us or just or come right at us? And after for a while they weren't sure. They were like, oh, it's heading our way, but it could miss, you know, like every time they say there's an asteroid coming within, you know, a certain thousands of miles of the Earth, and usually it misses. For a while, they weren't sure, but now they're pretty certain they've taken enough measurements, they've seen it move, and they can project confidently that these two things are going to collide. Also, Andromeda and Milky, we have a lot of gravity, and so you don't have to aim perfectly to get a collision, right, They're gonna um pull each other closer and closer. They want to collide, you know, you know what I mean, Like, it's not like a random asteroid. It's like we're we're pulling towards each other. Yeah, well, I don't know if you can really say they want Like, do you understand the psychology of the galaxy? Do you you know what galaxy wants in life? You know, Hey, galaxy have feelings, right, I think I read that science fiction novel right where every galaxy is actually a living thing and we're just like the tiny moats on the on an island of red blood cells instead of galaxy. Anyway, Yeah, so you don't have to shoot perfectly, and they're gonna collide. So to think about what happens in the collision, you probably think about each individual piece separately, Like we're a cluster of things. Like a galaxy is not a solid object. It's like a word almost like a cloud of things, right is that kind of way? Mean? Yeah, yeah, exactly. And you know, imagine two crowds right passing into each other, and like one gets off the train and one's coming down the stairs and they pass each other in the platform. What's going to happen, Well, it depends on how they interact, right, and how dense they are. So we can start with something and the obvious parts, like the stars. Okay, so you might think, oh my gosh, there's a hundred billion stars coming right at us. That's going to be a big deal. Is that the right size? Like it isn't drama about the same size as the Milky Way. Actually I think it's bigger than the Milky Way. But you know, factors of ten here are not important. Um, so it's hundreds of billions of stars, and each star, of course is really big. And you might think, while they're heading right at us, you know, this is gonna be a big deal, But remember that the stars are really far apart. Also, like, galaxies are huge, not just in terms of the number of stars, in terms of the amount of space they take up. And you know, you look around you in our galaxy, there aren't that many stars nearby, right, and the closest stars are light years away. I like this crowd analogy that's pretty interesting. Like we're a crowd of people getting off the subway. There's a crowd of people coming down the stairs to get on the subway. It's going to be a disaster potentially. Potentially, But if it's not rush hour and the crowds are pretty light, you know, there's like enough space the two crowds can just pass right through each other. Like if the stairways and the hallways are huge and people are pretty spread out, it may not be like a riot, you know, it may just be like a busy intersection. Right, It's like two people leaving Yankee Stadium at the same time as as somebody else's trying to come in. Like there's plenty of exits, nobody's gonna bump into each other, right, And that's sort of the case with stars. I read this one comparison where if you imagine the stars the size of a ping pong ball on average, the nearest stars three kilometers away, right, So like if you were going to throw a ping pong ball into a cloud of ping pong balls, where the spaces between them were three kilometers away. You'd be lucky if you hit anything, right, even if you were trying. Oh I see, Okay, So our galaxy is actually pretty sparse, meaning the stars are pretty far apart from each other. We're not sort of clumped together. Yeah, exactly, and astronomically speaking, astronomically speaking, and so there's gonna be very few or probably zero direct collisions. You know, where one star like actually slams into another one, you get stellar explosions. I mean, that would be pretty awesome. I would pay for front road seat, but I think it's pretty unlikely that's going to happen. But you know, there's a hundred billion stars running into a hundred billion other stars. Surely some of them are going to hit head on, isn't it. Aren't they? I mean, there's always a non zero probability, and you could get lucky you're unlucky, depending on which which outcome you're rooting for. But if they're diffuse enough, right, they're they're far enough apart, then then all of them could pass through without hitting. I mean, I think probably the most likely scenarios that maybe you get one. The stars also don't have to hit directly to affect each other. Right. Each one is a big blob of mass, which means it has gravity, and so they can jostle each other. I mean, if another star came by and near our Solar System and pass nearby, it could affect the orbits of all the planets, like nudge a planet out of orbit. Didn't have to hit the star directly head on or to affect our lives. It could maybe pull us out of orbit or sunk us into that other star. That's right, Um, it could it could steal planets right exactly. Or um, one of our planets could get ejected out of the Solar System right, or it could even kick our star out of the galaxy. Our star is in orbit around the center of the galaxy, right, and if it comes, if another star comes near enough, it could get pulled and so that it gets you out of that orbit, right. And orbit is sort of a delicate thing. You have to be the right radius and the right velocity for it all to work and start going to fast and you each escape velocity. And our star could even get kicked out of the galaxy. So we could be you know, sort of evicted from the Milky Way, floating in intergalactic space, just our star with the planets and everything. Oh, I see. So when two galaxies collided, it's not it's not we don't have to worry about things running into each other. But it is going to be pretty chaotic, right, Like, suddenly there's going to be you know, twice the number of stars, and that's just going to change everything, right, yeah, exactly, So things that definitely get mixed up. The stars won't necessarily smash into each other, but it definitely mix each other up and disturb each other. So are they are these two messages going to kind of go towards each other, makes a little bit and then keep going, or are they you know, slamming to each other and then become this giant mega galaxy. It depends a little bit on their relative velocity. If they're going fast enough relative to each other, then they'll pass through each other, right, But if if they're not, and it doesn't seem like they are, the most like scenario is that they merge, that they come together and there's a little bit of slashing or whatever, but eventually becomes one big galaxy. But wait, what does that mean? It's like the other stars and from the other galaxy. They're gonna come, but then they're going to kind of go pass us a little bit, and then they're gonna get pulled back in kind of thing like it's gonna like a giant jelly out in space, like it's going to go move, you know what I mean, but in slow motion, yeah, or sort of like things getting flushed down the toilet. You know, they come closer and closer and closer and circle each other faster and faster. You know, where we might circle each other, the two galaxies, Yeah, and sort of a wall being on top of each other, you know, so coming together pass a little the centers of mass might pass a little bit and then turn and come the other direction and spin it faster and faster until the center is a massive line. So being flushed down the toilet. That doesn't doesn't sound pleasant. Like that doesn't sound like it's going to be easy, do you know what I mean? Like, it doesn't sound like it's going to uh leave us unscathed. It might, though, you know, our sun could be totally fine, and it could be that the planets are not distorted, their orbits are not distorted, and we could just have a front row seat to a pretty amazing event. And the other thing is that we see this happening all the time. Like you look out into space with the hubble zoom in on other galaxies. There's lots of galaxies out there, and lots of them are in state various stages of emerging. And you can see galaxies that are just starting to merge. You can see galaxies that have been merging for a billion years. You can see galaxy that obviously merged a long time ago. And there's sort of like an uncomfortable blob of two galaxies, like one spiral arms sort of knocked off over here and there's another one over there. And so we have a lot of catalogs of examples of galaxies that have mergy. That's how we know so much about it. Yeah, if you look at there's a bunch of crashes that you can study. Yeah, exactly. So you want to know what galaxy collisions look like, you don't have to build a galaxy collider. This is one thing I love about astronomy. You have to google. You can just that's right, cosmic googling, otherwise known as telescopes. Um. You just look out into space and eventually you will see that thing happening, like you want to imagine some crazy scenario, or this kind of galaxy hits that kind of galaxy, and then from behind comes a third one that's happening somewhere out there there and you just need to find it and watch it. And so that's the amazing thing about astronomy is that all these cosmic experiments are happening. We just need to look for them. Okay, well we process that. Let's say, let's take a quick break, all right, So that's what might happen to the stars in the galaxy. What's going to happen to all these other parts of the galaxy when these two galaxies collide, right? And I like that we started with the stars because that's like the most important thing to us, because we're sort of staro centric, right, because we think stars are most the most important element of the galaxy. But the biggest element of the galaxy, remember, is dark matter. And so you might ask, well, what's going to happen to all our dark matter? And just like with the stars, what what happens there depends on how much it interacts. Currently, we don't really know anything about how much dark matter interacts. We know that it doesn't interact with normal matter. We think it doesn't interact with itself, or if it does, it doesn't interact very strongly and so, but it does have gravitational attraction. So if the galaxies are are going to hit each other and they're not moving too fast that they just basically pass right through each other, then the gravity from dark matter is going to affect the gravity from the other galaxies dark matter just the same way the stars are, and the two will sort of merge eventually become one big dark matter halo. And it's the kind of thing I would love to watch, but you can't really see the dark matter. It could be just another version of the cluster of stars. You know. It's like one blob goes into the other blob and then they kind of slash around and then just becomes a bigger blob. Yeah, you can think of the stars. It's sort of like a collisionless liquid, right, It's like a you have a liquid of stars that don't interact with each other the same way the dark matter does. So dark matter in stars are basically operating this under the same principles. The only relevant interaction that we know about is gravity, So everything we said about stars is also going to affect the big blobs of dark matter. The dark matter is much more continuous. We think it's smooth. It's not like there's just dots of it here and there. But because it hardly interacts with each other, it doesn't matter if it rams smack into itself. Right, It mainly affect is gravitational. It may not interact with itself. It could just pass by itself and not really kind of explode or collide or do anything besides pull itself gravitationally. Yeah, exactly. And we don't even know what dark matter is made out, so we can't say things like dark runner particles can do this. Dark matter as far as we know, it's just smooth, collisionless blob of something. And we know it has gravitational interactions, and that's really about all we know about it. So we think that that that's what's going to happen. And you know, we've seen dark matter in these gravitational collisions and we see that it basically sticks with the galaxies, right, it sticks with the stars. Okay, so then the last part is the black hole at the center of each galaxy. What no, no, don't forget the dust, right, this gas dust, which a lot of people overlook, and this is actually the most exciting part because the dust is the most the coolest part. That's how you know you're listening to a nerdy podcast and they get excited about dust. Oh my god. You know if if for those people who are like expecting dramatic events and explosions, this is where you get them. Okay, because dust is not diffuse, right's spread everywhere, Like you have a big blob of dust. It's not like little clusters of mass the way stars are. It's a huge extended blob of dust. And when it smashes into another blob of dust, you're going to get fireworks. Like those clouds of dust interact with each other the way dark matter doesn't. And they're um spread everywhere the way stars aren't, and so you get huge collisions. And what happens when you compress gas and dust. What happens when you collide huge blobs of gas and dust is you get more dense and then you get stars. And so you could see like new stars being born where these two huge clouds of gas and dust being into each literally like fireworks. Like that's right, cosmic fireworks. I mean, what's more are dramatic and what's a better cosmic firework than seeing stars be born? Yeah, so this one is going to be like to you know, you know, two liquids kind of running into each other. It is going to be kind of dramatic, you know, like it is going to be like with the sound effects and everything in space. No, yeah, exactly, It's just like two water balloons hitting each other. Right, You're gonna get an initial shop wave. And you know, you don't get stars born when you fire water balloons at each other because the density isn't great enough obviously, But yeah, you're gonna get a shock wave. You're gonna get friction between the fluids, and you're going to get stars being born. It's gonna be pretty dramatic. So you don't want to be there. You don't want to want to But we are, aren't We surrounded by gas clouds and stuff? Oh? I think you need denser stuff. I mean, the milky wave definitely has big clouds of gas and dust. Oh I see, But when those clouds running to the other clouds, then that's where this stuff happens. But we're not necessarily sitting in one of those clouds. That's right, yeah, okay, the last element is the black hole, right, and so our galaxy is a huge black hole the center, and the other guy, almost every other galaxy is a huge black hole of the center. And there it's gonna be mostly dominated by gravity, right, because they're gonna pull each on each other really hard, and they're gonna pass by each other a little bit, perhaps because they're probably not gonna hit dead on and then they're gonna swing around. They're gonna pull on each other, so they'll probably be you know, some sort of a near miss, and then they'll turn around and come back. And then they'll just circle each other faster and faster and faster. And if you remember the episode we did on gravitational waves, or if you've heard about the discovery of gravitational waves, you know that what happens when black holes get close to each other as they start to circle each other faster and faster, until eventually they spend really really fast and the distance get closer and closer and closer, and then they merge and they become one enormous black hole. They like eat each other, right, But and it's not a peaceful event it's like a pretty violent thing, right, Like they've been super super fast, there's energy spewed out everywhere, and then suddenly have these huge cataclysmic gravitational waves. Oh yeah, when black holes fight, it's a big mess. Absolutely. You don't want to be anywhere near that because huge amounts of radiation, not just gravitational waves. Right, yeah, you make gravitational waves, which are pretty awesome from a physics point of view, but you know, these things tear up into each other and amid huge amounts of radiation, and so you don't want to be anywhere near that. Yeah, I mean that that's gonna like sterilize life on any nearby star system for sure. But anyway, there probably isn't any life in the center of art galaxy for that same reason that the galactic black hole is already emitting huge amounts of life killing radiation, so you don't want to get too close anyway. It's like the eye of a storm. There's nothing living in the middle of it, that's right. I don't know if it's calm inside the black hole. That we did a whole episode actually on what it's like to be inside a black hole. So you guys should go listen to that. But yeah, it's a it's everything is swirling around that central black hole. And so probably what will happen is they'll merge and the new milk, the new galaxy. I wonder what that galaxy would be called. Actually, how would you combine and Rameda in the Milky Way, like Drama Dinky Way, milk milk Drameda, I don't know, and ramedaway the Andromeda Away. There you go, the Andromeda Way. Yeah, the new galaxy would have a huge, super duper massive black hole at its center. Yeah, and so I think that basically sums it up. You'd have the black holes will probably emerge huge violent eruption of radiation there gas and the dust would have a lot of friction caused caused star formation, big explosion, bigion work, Yeah, exactly. Friction, Yeah, just all the kind of stuff you expect to see in the next Transformers movie. And then stuff. He'll be there, He'll be there everything. If there's money to be made, he'll be there. Um. And then the stars and the dark matter will just have a gravitational effect, but they'll know eventually settle down and in a few more billion years, the new galaxy will have its own shape. It will sort of settle into its own new shape. But it kind of sounds like every part will do something. Friend, do you know what I mean? Yeah, they will because they follow different rules, right, they interact differently and so but so, then kind of the nice structure we have now is going to be pretty much obliterated right when it we're just with the other one. Yeah, exactly. You shouldn't count on your real estate being the same value. After the galaxy collision, Everything's going to be shook up, right, Absolutely, it's going to be disrupt the entire Both galaxies gonna be totally disrupted. Fireworks collisions. But you're saying it's possible we may survive it, right, that it's possible nothing will actually happen to our solar system. I think that's the most likely outcome. Yeah, is it will just be sort of interesting likely, Yeah, most likely most likely thing. I mean, we're a star. We were basically part of our star, right you think of the Solar system is just one big blob, And the most likely thing is that nothing gets close enough to disrupt our orbit around the star. And you know what, even if our star gets like ejected from the galaxy. So what we don't need the galaxy. We could live just fine, just a star with a bunch of planets in the middle of intergalactic space. We don't need anything else. We just never start to provide energy for life. So so we don't mean just in the same way we're talking about the beginning of the episode, like you don't really notice what's going out in space because you don't usually have to. And if all those if all those stars disappeared and all we and we were in the middle of intergalactic space, it wouldn't change your life at all. You would still still need to stock up on lentils for the coming Apoco lips. You know, it wouldn't save you or change your plans at all. You wouldn't mind getting kicked out of town like that. That's kind of what it would feel like, like the whole town, our whole town. We just get kicked out, you know, and we just go on living the way what we did before. But things will definitely change for us even if we survived it's galactic collision, the night sky will look very different. I mean, as Andromeda approaches in the next few billion years, it will grow in the sky and eventually look really big. And then after the collision, right when things have settled down, the night sky would look totally different because all the stars will have been rearranged and we won't see that band in the milky Way anymore. Well, that makes me feel better. I was sweating. I was sweating what was gonna happen for and I have been years from now. But now now I feel better and I and I hope Blake you also feel a little bit better. Yeah, that's right, Bake, chill out, don't worry about it. Um, you have nothing to worry about. I think it's fun to think about things happening deep into the future, and also even further into the future. You know, the universe has been around fourteen billion years, right, and that's just sort of like the initial bits, not before we get to the interesting part. But it could be they were not even at the interesting part. You know. Thinking about galaxies in this way reminds you that they're spinning their dynamic, they're swirling around each other. What's going to happen? We don't know, right, they could continue to swirl and form crazy new structures that know, the universe has never seen before. Because there hasn't been time to make them. And so this is the kind of thing makes me think about the universe, like on the trillion or two trillion life year cycle, Like if life is still around ten trillion years into the history of the universe, they'll think about these first few moments of lactic formation as you know, almost irrelevant, just like just warming up. The best maybe yet to come. Now, that's right. I'm an optimistic person, so I'm always hoping that the best thing is yet to come. Exactly well, great, um, thank you so much Bla for sending us this question. We really enjoyed answering it. That's right. And check out our book called We Have No Idea. It's a guide to the unknown questions of the universe, all the things that physics wants to know the answer to but really hasn't got a clue about. And thanks for listening. Yeah, and if you're hungry or want to stuck up, just don't forget to get Daniel's Spicy lentils, now available at your local grocery store. If you still have a question after listening to all these explanations, please drop us a line. We'd love to hear from you. You can find us at Facebook, Twitter, and Instagram at Daniel and Jorge That's one Word, or smail us at Feedback at Daniel and Orge dot com. H m hm