Latest / Daniel and Kelly’s Extraordinary Universe / What Happens When Galaxies Collide?

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What Happens When Galaxies Collide? · Daniel and Kelly’s Extraordinary Universe

• 0:07
  Speaker 1: Hey, Daniel, what keeps you up at night? Oh? I
• 0:10
  Speaker 1: worry about a lot of things. Financial crises, my kids
• 0:14
  Speaker 1: growing up to be just like me, all sorts of stuff.
• 0:16
  Speaker 1: I worry about that too for them. You worry about
• 0:20
  Speaker 1: my kids growing up to be just like me. We
• 0:22
  Speaker 1: can't have more of him in the world, Okay, But
• 0:26
  Speaker 1: like on a galactic scale, on a universe scale, what's
• 0:29
  Speaker 1: something we should be concerned about. Well, we do have
• 0:31
  Speaker 1: a lot of things look forward to in terms of
• 0:33
  Speaker 1: our galaxy. If we survived the Sun exploding and the
• 0:35
  Speaker 1: waters the Earth boiling off, then we have something pretty
• 0:38
  Speaker 1: dramatic to look forward to, which is that our galaxy,
• 0:41
  Speaker 1: the Milky Way, is going to collide with their nearest
• 0:44
  Speaker 1: neighbor and Dromeda. Meaning right now, there's an entire galaxy
• 0:47
  Speaker 1: Drameda heading towards us at this very moment. That's right.
• 0:51
  Speaker 1: It's like somebody shot it at us with a slingshot
• 0:54
  Speaker 1: and it's zooming right towards us, and it's going to
• 0:56
  Speaker 1: hit us smack on him. And I'm Daniel, and this
• 1:17
  Speaker 1: is our podcast. Daniel and Jorge explained the universe on
• 1:21
  Speaker 1: the episode. Today, we're going to talk about what will
• 1:27
  Speaker 1: happen when galaxies collide. Is this something we should all
• 1:31
  Speaker 1: be worrying about our packing our bags, about building our
• 1:34
  Speaker 1: underground shelters or are we all screwed? Or is it
• 1:36
  Speaker 1: just going to be like a big nothing? How much
• 1:39
  Speaker 1: should I pack? You should definitely be stalking lentils no
• 1:43
  Speaker 1: matter what. Lentils are a good investment for any of
• 1:45
  Speaker 1: these end of the world. Not just beans, no, no, lentils.
• 1:49
  Speaker 1: I mean lentils are kind of lego for a galactic emergency.
• 1:53
  Speaker 1: That's the that's the one to go with. Yeah, absolutely,
• 1:56
  Speaker 1: I would. I would invest in lentils heavily. And it's
• 1:58
  Speaker 1: not just because I happened to purchase lentils just before
• 2:00
  Speaker 1: we recorded this podcast and I'm trying to drum up
• 2:03
  Speaker 1: the lentil futures, you know. I'm I'm sincerely worried about
• 2:07
  Speaker 1: our listeners, and I encourage you all to go out
• 2:09
  Speaker 1: there in stockpi lentils. Well that's a whole hill of
• 2:11
  Speaker 1: beans worth of advice right there, that's right. And so
• 2:15
  Speaker 1: this is the question and today's podcast, what will happen
• 2:18
  Speaker 1: when our galaxy, the Milky Way, collides with the neighboring galaxy?
• 2:21
  Speaker 1: And this question I love not just because it's huge
• 2:24
  Speaker 1: and dramatic and galactic and all this sort of stuff,
• 2:26
  Speaker 1: but because it was suggested by one of our listeners.
• 2:29
  Speaker 1: That's right. It's Blake from Australia who listens to this
• 2:33
  Speaker 1: podcast on her commute to work every day. That's right.
• 2:36
  Speaker 1: And she didn't tell us what she uses to commute.
• 2:38
  Speaker 1: Maybe she rides in a beautiful pickup truck, maybe she's
• 2:41
  Speaker 1: in the back of a limo, maybe rides kangaroo who knows,
• 2:45
  Speaker 1: that's right, with a really nice sound system. Yeah, but
• 2:49
  Speaker 1: she has some interesting feedback for us about our podcast. Right,
• 2:52
  Speaker 1: what did she say? Yeah, she said that she likes
• 2:54
  Speaker 1: listening to me explain things, but she also likes when
• 2:57
  Speaker 1: you interrupted me. She said that often you interrupt me
• 3:00
  Speaker 1: just the same moment when she has a question and
• 3:03
  Speaker 1: you pose the same question that was bouncing around in
• 3:05
  Speaker 1: her head that she was shouting at her limo sound
• 3:08
  Speaker 1: system or kangaroo speakers or whatever it is she us
• 3:10
  Speaker 1: going to listen to. And so I was glad for that,
• 3:13
  Speaker 1: because you know, I like when you interrupt me. Also
• 3:15
  Speaker 1: it breaks the flow and it keeps me from just
• 3:18
  Speaker 1: droning on and on and on. So Thank you Blake
• 3:20
  Speaker 1: for suggesting this topic, and thank you Orge for occasionally interrupting. Yeah, no,
• 3:24
  Speaker 1: I'm happy to be rude. It seems to come naturally. Yeah, yeah,
• 3:31
  Speaker 1: And so that's the topic of today's podcast, And we
• 3:34
  Speaker 1: thought first before we dove into it, we would walk
• 3:37
  Speaker 1: around like we usually do and ask people, are you
• 3:39
  Speaker 1: worried about a galactic collision? What do you think will
• 3:41
  Speaker 1: happen when our galaxy collides with a neighboring galaxy? So
• 3:45
  Speaker 1: put that image in your mind to giant galaxies, full
• 3:49
  Speaker 1: stars running into each other. What do you think is
• 3:52
  Speaker 1: going to happen? Here's what people had to say, big explosion.
• 3:57
  Speaker 1: We'd probably all die. It is going to be mostly
• 4:01
  Speaker 1: nothing because of all the empty space around the world,
• 4:04
  Speaker 1: although there will be some crushes and so on in
• 4:07
  Speaker 1: the way. Okay, probably somewhere between a glacial, slow event
• 4:10
  Speaker 1: that we won't even notice and nothing at all. Maybe
• 4:13
  Speaker 1: leaning towards nothing at all. I think it would probably
• 4:17
  Speaker 1: be a big explosion with something pretty crazy happening. All right,
• 4:21
  Speaker 1: That was a little anti climatic. People seem to have
• 4:24
  Speaker 1: very low expectations of this event. What do you mean
• 4:26
  Speaker 1: It seems like half of the people are like it's
• 4:27
  Speaker 1: gonna be nothing, and the other half of like big explosions,
• 4:30
  Speaker 1: we're all gonna die. Well, why do you why do
• 4:36
  Speaker 1: you think Blake asked this question? Do you think there's
• 4:38
  Speaker 1: something she's concerned about or is something she's curious about?
• 4:40
  Speaker 1: You know? I think Blake is probably deciding whether or
• 4:42
  Speaker 1: not to stock up on lentils. You know, Um, she's
• 4:46
  Speaker 1: probably right now, story she asked. I think it's part
• 4:50
  Speaker 1: of just trying to be a sort of a citizen
• 4:53
  Speaker 1: of the larger universe, you know, wondering where we stand
• 4:56
  Speaker 1: and trying to think bigger than just our planet, you know,
• 4:58
  Speaker 1: because there's so much going on out there, it's so
• 5:01
  Speaker 1: easy to just walk around on the surfaces planet never
• 5:03
  Speaker 1: really look up and remember that there is an enormous
• 5:06
  Speaker 1: amount of stuff happening out there, And then you wonder like, well,
• 5:09
  Speaker 1: how is that relevant to me? And is he going
• 5:11
  Speaker 1: to ruin my life? Or can I go on ignoring it? Um? So,
• 5:14
  Speaker 1: I think maybe she was just sort of thinking into
• 5:16
  Speaker 1: the deep future and wondering like, how long can this
• 5:18
  Speaker 1: whole ridiculous, beautiful thing we call life on Earth go on? Right?
• 5:23
  Speaker 1: Is it going to change from how it is now, right, Yeah,
• 5:25
  Speaker 1: exactly do I need to change the way I live?
• 5:28
  Speaker 1: Does it affect any decision making? On the other hand,
• 5:30
  Speaker 1: it could be that Blake, like many people, is just
• 5:33
  Speaker 1: a thinker and likes to think about these scenarios, and
• 5:35
  Speaker 1: she probably heard that the Milky Way will collide with
• 5:38
  Speaker 1: Andromeda and wonder like, what's that going to be? Like?
• 5:40
  Speaker 1: You know this this this is the other side of
• 5:42
  Speaker 1: me that likes to smash stuff together. I mean, I'm
• 5:45
  Speaker 1: a particle physicist, but then we have the whole universe
• 5:47
  Speaker 1: to play with, right, and so you might wonder, like
• 5:49
  Speaker 1: what happens when planets collide, what happens when solarcisms? Like
• 5:52
  Speaker 1: oh my gosh, what if we could build a galaxy
• 5:55
  Speaker 1: collider and shoot them against each other and smash them
• 5:57
  Speaker 1: into each other? Right, So it just comes out of
• 5:59
  Speaker 1: like a curiosity to see stuff break by smashing it together. Yeah, well,
• 6:03
  Speaker 1: let's let's take it step back and just kind of
• 6:05
  Speaker 1: think about why even galaxies would collect, Like is this
• 6:09
  Speaker 1: a relevant question that is something that happens a lot
• 6:12
  Speaker 1: galaxies colliding, or is it something that's incredibly rare. It
• 6:15
  Speaker 1: turns out galaxies colliding happens all the time. It's like
• 6:18
  Speaker 1: a totally natural thing. And our galaxy. Yeah, not only
• 6:22
  Speaker 1: will our galaxy collide with and John Day in a
• 6:24
  Speaker 1: few billion years, it's currently colliding with other smaller galaxies.
• 6:28
  Speaker 1: That what Yeah, we're in a collision right now. Yeah,
• 6:33
  Speaker 1: that's right. And remember that the galactic time scales are
• 6:36
  Speaker 1: very different. You know, the galaxy takes about two hundred
• 6:39
  Speaker 1: million years just to rotate once, to go around once. Yeah,
• 6:44
  Speaker 1: so one galactic year is two hundred million earth years.
• 6:49
  Speaker 1: But it looks so swirly. It looks you know, you
• 6:52
  Speaker 1: know what I mean, Like it looks like it's in motion,
• 6:54
  Speaker 1: but it's actually it is. It is in motion, it's
• 6:57
  Speaker 1: just very slow, right, And so all these things are
• 7:00
  Speaker 1: dancing around each other and sometimes they bump into each other.
• 7:03
  Speaker 1: And the thing I think is amazing is that, you know,
• 7:05
  Speaker 1: until like a hundred years ago, we didn't even know
• 7:08
  Speaker 1: there were other galaxies. Like we looked up at the
• 7:11
  Speaker 1: night sky and we saw stars, and we thought, oh,
• 7:13
  Speaker 1: there's just stars that go on forever. At the universe
• 7:16
  Speaker 1: is just filled with stars. The universe is just like
• 7:18
  Speaker 1: a giant MESSI pinpoints, right, just stars. Yeah, yeah, like
• 7:22
  Speaker 1: somebody had scattered stars across the cosmos, right, And it
• 7:26
  Speaker 1: was Hubble, the guy for whom the telescope and the
• 7:30
  Speaker 1: constant are named. He's the guy who figured out, oh,
• 7:32
  Speaker 1: some of those things that are really far out there
• 7:33
  Speaker 1: are not stars. There are other galaxies. Right, So there's
• 7:37
  Speaker 1: the universe is filled with other galaxies. And of course
• 7:39
  Speaker 1: there are more galaxies than stars, and and then each galaxy,
• 7:42
  Speaker 1: of course, contains hundreds of billions of stars, and so
• 7:46
  Speaker 1: the numbers pretty quickly blow your head up before you
• 7:48
  Speaker 1: can understand them. But the point I wanted to make
• 7:51
  Speaker 1: was that we didn't realize there were galaxies until recently,
• 7:54
  Speaker 1: and now we're realizing that galaxies are in motion relative
• 7:57
  Speaker 1: to each other, and they're moving. Like the these galaxies
• 8:00
  Speaker 1: that we see out there in the sky, they're not
• 8:02
  Speaker 1: just like hanging there in space never to change, right,
• 8:05
  Speaker 1: They are moving their dynamic things, and they're constantly in motion,
• 8:09
  Speaker 1: and they have huge gravitational attraction. Well, let's break it down.
• 8:12
  Speaker 1: What exactly is a galaxy? I mean, I know it's
• 8:14
  Speaker 1: like kind of like a collection of stars, but you
• 8:17
  Speaker 1: know what, why do stars clump together like that? First
• 8:21
  Speaker 1: of all? And what makes a galaxy special? Like, why
• 8:24
  Speaker 1: is it more than just a clump of stars. Well,
• 8:27
  Speaker 1: what makes our galaxy special is that you're in it. Horse.
• 8:29
  Speaker 1: There's no other galaxy that features such a good looking,
• 8:33
  Speaker 1: funny cartoonists, meet me and lentils. We make it, make
• 8:37
  Speaker 1: it habitable, right, Okay, so what's the recipe for a galaxy? Right? Well,
• 8:42
  Speaker 1: the thing that the galaxies have the most of, remember,
• 8:45
  Speaker 1: is dark matter. In general, there's about five times as
• 8:49
  Speaker 1: much dark matter as there is any other kind of matter,
• 8:52
  Speaker 1: you know, the stuff that makes up gas and dustin
• 8:54
  Speaker 1: stars and people and cartoonists and and and ice cream.
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  Speaker 1: So it's mostly dark matter. So that's the stuff we
• 9:00
  Speaker 1: can't see your touch. I mean, we did a whole
• 9:02
  Speaker 1: podcast episode on dark matter, but it just in case
• 9:05
  Speaker 1: somebody didn't listen to it. Um, it's like this weird
• 9:08
  Speaker 1: invisible dark gravity thing that's hanging out every galaxy has,
• 9:15
  Speaker 1: that's right. Yeah, we call it dark and matter because
• 9:17
  Speaker 1: we can't see it. So it's dark and we know
• 9:19
  Speaker 1: it gives gravity, so therefore it's matter and the crazy
• 9:23
  Speaker 1: things that until you know, a few decades ago, we
• 9:25
  Speaker 1: didn't even know it existed. And now we know that
• 9:27
  Speaker 1: galaxies are mostly made up of this stuff. Right. So
• 9:31
  Speaker 1: number one ingredient when you want to make a galaxy
• 9:33
  Speaker 1: is you have to have dark matter. It's like five
• 9:35
  Speaker 1: times more than the stars, right, yeah, exactly, Like a
• 9:37
  Speaker 1: galaxy is basically a clump of dark matter with a
• 9:40
  Speaker 1: few sprinkles of stars in it. That's right. Yeah. If
• 9:42
  Speaker 1: a galaxy was a cupcake, right, the dark matter would
• 9:45
  Speaker 1: be the chocolate cake, and you know there everything else
• 9:48
  Speaker 1: would be the frosting and the sprinkles. The gas and
• 9:51
  Speaker 1: the dust would be the frosting. The stars would be
• 9:53
  Speaker 1: the sprinkles on top. Oh I see, Okay, that's kind
• 9:55
  Speaker 1: of the right proportions. Yeah, something like that. Um, So
• 9:59
  Speaker 1: you start with big blob of dark matter and that's
• 10:02
  Speaker 1: most of it, and then after that you have huge
• 10:04
  Speaker 1: amounts of gas and dust, right, And that's the stuff
• 10:07
  Speaker 1: that's left over from the Big Bang or left over
• 10:09
  Speaker 1: from stars exploding, and those the ingredients you need to
• 10:12
  Speaker 1: make planets and stars and all sorts of stuff that
• 10:15
  Speaker 1: you're familiar with, right. And so you have dark matter,
• 10:18
  Speaker 1: you have gas, you have dust, you have planets and
• 10:22
  Speaker 1: stars and black holes right, Like there's just a little
• 10:26
  Speaker 1: black hole sprinkled throughout throughout probably, But there's a huge
• 10:30
  Speaker 1: giant black hole at the center of every galaxy. That's right.
• 10:33
  Speaker 1: I can't believe I forgot the black hole. The black
• 10:35
  Speaker 1: hole at the center of almost every galaxy is huge.
• 10:38
  Speaker 1: It's like, you know, millions of solar masses and it's
• 10:40
  Speaker 1: sitting there at the center of the black hole, and
• 10:42
  Speaker 1: it's it's got a lot of stuff to it also, right,
• 10:44
  Speaker 1: it carries a lot of mass and so it contributes.
• 10:47
  Speaker 1: So that's what a galaxy is. And you know, a
• 10:49
  Speaker 1: galaxy couldn't really form without all those elements, Like you
• 10:51
  Speaker 1: couldn't really have a galaxy without dark matter because dark
• 10:54
  Speaker 1: matter provides the gravitational attraction to suck all this stuff together.
• 10:58
  Speaker 1: You know, they do these simulations of the universe. They say,
• 11:00
  Speaker 1: what would the universe look like if you never had
• 11:02
  Speaker 1: dark matter in it? And it would take a lot
• 11:04
  Speaker 1: longer for galaxies to form because dark matter has pulled
• 11:08
  Speaker 1: all this stuff together. It's like it's made a you know,
• 11:10
  Speaker 1: like a well in the rubber sheet of the universe,
• 11:12
  Speaker 1: so everything rolls together more closely. Okay, so that's a
• 11:20
  Speaker 1: that's a galaxy. It's a black hole surrounded by dark
• 11:23
  Speaker 1: matter and sprinkles of stars and gas and dust and
• 11:26
  Speaker 1: lintels and lintels exactly yes, And so they're not just
• 11:31
  Speaker 1: hanging out in space. They're moving around. That's right there.
• 11:34
  Speaker 1: Each one is spinning, right, which is why you see
• 11:36
  Speaker 1: a lot of them having these these spiral features. Each
• 11:39
  Speaker 1: one is spinning, and then they're also moving around each other.
• 11:42
  Speaker 1: They have gravity and they're moving around each other, and
• 11:45
  Speaker 1: they have these Each galaxy is a member of a
• 11:47
  Speaker 1: cluster of galaxies, and so these guys are orbiting the
• 11:50
  Speaker 1: center of the cluster. And then the clusters are members
• 11:53
  Speaker 1: of superclusters. So these things have a lot of gravitational
• 11:57
  Speaker 1: interactions everywhere. It's like a system of galaxy. They all
• 12:01
  Speaker 1: interact with each other, and they all spin around their
• 12:04
  Speaker 1: common center of mass exactly right, And they're all spinning
• 12:07
  Speaker 1: around that center. So it's sort of like a big
• 12:09
  Speaker 1: slow motion tornado. Right you looked at it. If you
• 12:12
  Speaker 1: looked at it really really slow, you're like, oh, nothing's
• 12:14
  Speaker 1: really moving. I mean, I guess a little bit, but
• 12:16
  Speaker 1: you you you watch it at natural speed of tornado,
• 12:19
  Speaker 1: and obviously it's going really fast, and so a galaxy
• 12:21
  Speaker 1: is that's sort of that same way. The gather system
• 12:23
  Speaker 1: of galaxies is sort of that same way, but they're
• 12:26
  Speaker 1: all moving around each other and then occasionally, you know,
• 12:28
  Speaker 1: they bump into each other. Wow, that's so weird to
• 12:30
  Speaker 1: think that gravity works the way like we are, you know,
• 12:33
  Speaker 1: moving around the center of the Earth. The Earth is
• 12:36
  Speaker 1: moving around our solar system, around the center of gravity,
• 12:39
  Speaker 1: which is mostly the Sun, but the Sun is also
• 12:41
  Speaker 1: we were moving around the center of gravity of the galaxy,
• 12:43
  Speaker 1: and the galaxy is also moving around the center of
• 12:46
  Speaker 1: gravity of its cluster of galaxies. That's right, Yeah, and
• 12:50
  Speaker 1: on and on and on like a bunch of nested
• 12:52
  Speaker 1: Russian dolls, you know, until you get to the biggest
• 12:55
  Speaker 1: structures in the universe, you know, which are the superclusters,
• 12:57
  Speaker 1: and then the filaments of superclusters, and beyond that, we
• 13:00
  Speaker 1: don't know anything about whether there are bigger and bigger structures.
• 13:03
  Speaker 1: That's as far as we've seen. So we're moving around
• 13:05
  Speaker 1: and sometimes these two two galaxies can just run into
• 13:09
  Speaker 1: each other. In the giant, vastness of space, all these
• 13:12
  Speaker 1: moving galaxies can sometimes cross pass right. Yeah. And there's
• 13:16
  Speaker 1: another thing I want to say about that before we
• 13:18
  Speaker 1: talk about what actually happens, which is that it's incredible
• 13:20
  Speaker 1: to me that gravity is the force that's dominant on
• 13:23
  Speaker 1: these scales, right, Like, that's the thing that's controlling how
• 13:27
  Speaker 1: galaxies form and how they dance around each other, and
• 13:29
  Speaker 1: that's pulling them all the way through the universe and
• 13:31
  Speaker 1: forming these crazy structures. It's all gravity, right. But gravity
• 13:35
  Speaker 1: is the weakest force of nature. It's weaker than electromagnetism,
• 13:38
  Speaker 1: it's weaker than any of the nuclear forces. It's pathetically weak,
• 13:42
  Speaker 1: but it's the only one that operates on these huge scales,
• 13:45
  Speaker 1: and it can't be balanced out. And so because it's
• 13:48
  Speaker 1: only an attractive force, there's no repulsive version of it.
• 13:52
  Speaker 1: And so that's why, like on these huge scales, gravity
• 13:55
  Speaker 1: is the thing that dominates. Gravity determines the structure the
• 13:57
  Speaker 1: Solar system, the structure the galaxy, the structure of the clusters.
• 14:01
  Speaker 1: Gravity sort of winds in the end. It's like, you know,
• 14:03
  Speaker 1: revenge of the nerd forces, Right, It's the weakest force
• 14:06
  Speaker 1: in the end controls the universe. It's like slow and
• 14:09
  Speaker 1: steady wins the race. It's the turtle of forces. Yeah, Anyway,
• 14:14
  Speaker 1: we need to do a whole other podcast on why
• 14:16
  Speaker 1: gravity is so weird and weak and whatever, and we're
• 14:18
  Speaker 1: into that. Okay, so we have a cult clusters and
• 14:21
  Speaker 1: galaxies are moving around space and sometimes they collide. So yeah,
• 14:25
  Speaker 1: let's talk about what actually happens when two of these
• 14:27
  Speaker 1: things collide. But first let's take a quick break. All right.
• 14:42
  Speaker 1: So we're sitting in a galaxy and we are moving
• 14:46
  Speaker 1: inside of this galaxy, and this galaxy is moving in space.
• 14:49
  Speaker 1: But there's another galaxy nearby called the Andromeda galaxy, and
• 14:52
  Speaker 1: it's kind of an interset course with us, right, like
• 14:56
  Speaker 1: we're going to run into it in about four and
• 14:58
  Speaker 1: a half billion years. Yeah, not kind of. They've measured it.
• 15:01
  Speaker 1: They can measure the velocity of Andromeda relative to us,
• 15:04
  Speaker 1: and they can see that it's getting closer and closer
• 15:06
  Speaker 1: every year, and they can also measure the lateral velocity,
• 15:09
  Speaker 1: like is it going to shoot by us or just
• 15:11
  Speaker 1: or come right at us? And after for a while
• 15:14
  Speaker 1: they weren't sure. They were like, oh, it's heading our way,
• 15:16
  Speaker 1: but it could miss, you know, like every time they
• 15:18
  Speaker 1: say there's an asteroid coming within, you know, a certain
• 15:21
  Speaker 1: thousands of miles of the Earth, and usually it misses.
• 15:24
  Speaker 1: For a while, they weren't sure, but now they're pretty
• 15:26
  Speaker 1: certain they've taken enough measurements, they've seen it move, and
• 15:29
  Speaker 1: they can project confidently that these two things are going
• 15:31
  Speaker 1: to collide. Also, Andromeda and Milky, we have a lot
• 15:34
  Speaker 1: of gravity, and so you don't have to aim perfectly
• 15:37
  Speaker 1: to get a collision, right, They're gonna um pull each
• 15:40
  Speaker 1: other closer and closer. They want to collide, you know,
• 15:44
  Speaker 1: you know what I mean, Like, it's not like a
• 15:45
  Speaker 1: random asteroid. It's like we're we're pulling towards each other. Yeah, well,
• 15:49
  Speaker 1: I don't know if you can really say they want Like,
• 15:51
  Speaker 1: do you understand the psychology of the galaxy? Do you you
• 15:53
  Speaker 1: know what galaxy wants in life? You know, Hey, galaxy
• 15:56
  Speaker 1: have feelings, right, I think I read that science fiction
• 16:01
  Speaker 1: novel right where every galaxy is actually a living thing
• 16:04
  Speaker 1: and we're just like the tiny moats on the on
• 16:06
  Speaker 1: an island of red blood cells instead of galaxy. Anyway, Yeah,
• 16:09
  Speaker 1: so you don't have to shoot perfectly, and they're gonna collide.
• 16:12
  Speaker 1: So to think about what happens in the collision, you
• 16:14
  Speaker 1: probably think about each individual piece separately, Like we're a
• 16:16
  Speaker 1: cluster of things. Like a galaxy is not a solid object.
• 16:19
  Speaker 1: It's like a word almost like a cloud of things,
• 16:21
  Speaker 1: right is that kind of way? Mean? Yeah, yeah, exactly.
• 16:24
  Speaker 1: And you know, imagine two crowds right passing into each other,
• 16:28
  Speaker 1: and like one gets off the train and one's coming
• 16:30
  Speaker 1: down the stairs and they pass each other in the platform.
• 16:32
  Speaker 1: What's going to happen, Well, it depends on how they interact, right,
• 16:35
  Speaker 1: and how dense they are. So we can start with
• 16:38
  Speaker 1: something and the obvious parts, like the stars. Okay, so
• 16:41
  Speaker 1: you might think, oh my gosh, there's a hundred billion
• 16:43
  Speaker 1: stars coming right at us. That's going to be a
• 16:46
  Speaker 1: big deal. Is that the right size? Like it isn't
• 16:48
  Speaker 1: drama about the same size as the Milky Way. Actually
• 16:51
  Speaker 1: I think it's bigger than the Milky Way. But you know,
• 16:53
  Speaker 1: factors of ten here are not important. Um, so it's
• 16:56
  Speaker 1: hundreds of billions of stars, and each star, of course
• 16:58
  Speaker 1: is really big. And you might think, while they're heading
• 17:00
  Speaker 1: right at us, you know, this is gonna be a
• 17:02
  Speaker 1: big deal, But remember that the stars are really far apart. Also, like,
• 17:05
  Speaker 1: galaxies are huge, not just in terms of the number
• 17:08
  Speaker 1: of stars, in terms of the amount of space they
• 17:11
  Speaker 1: take up. And you know, you look around you in
• 17:14
  Speaker 1: our galaxy, there aren't that many stars nearby, right, and
• 17:17
  Speaker 1: the closest stars are light years away. I like this
• 17:20
  Speaker 1: crowd analogy that's pretty interesting. Like we're a crowd of
• 17:23
  Speaker 1: people getting off the subway. There's a crowd of people
• 17:26
  Speaker 1: coming down the stairs to get on the subway. It's
• 17:29
  Speaker 1: going to be a disaster potentially. Potentially, But if it's
• 17:33
  Speaker 1: not rush hour and the crowds are pretty light, you know,
• 17:35
  Speaker 1: there's like enough space the two crowds can just pass
• 17:37
  Speaker 1: right through each other. Like if the stairways and the
• 17:39
  Speaker 1: hallways are huge and people are pretty spread out, it
• 17:42
  Speaker 1: may not be like a riot, you know, it may
• 17:44
  Speaker 1: just be like a busy intersection. Right, It's like two
• 17:47
  Speaker 1: people leaving Yankee Stadium at the same time as as
• 17:50
  Speaker 1: somebody else's trying to come in. Like there's plenty of exits,
• 17:53
  Speaker 1: nobody's gonna bump into each other, right, And that's sort
• 17:56
  Speaker 1: of the case with stars. I read this one comparison
• 17:58
  Speaker 1: where if you imagine the stars the size of a
• 18:01
  Speaker 1: ping pong ball on average, the nearest stars three kilometers away, right,
• 18:06
  Speaker 1: So like if you were going to throw a ping
• 18:08
  Speaker 1: pong ball into a cloud of ping pong balls, where
• 18:11
  Speaker 1: the spaces between them were three kilometers away. You'd be
• 18:13
  Speaker 1: lucky if you hit anything, right, even if you were trying.
• 18:16
  Speaker 1: Oh I see, Okay, So our galaxy is actually pretty sparse,
• 18:22
  Speaker 1: meaning the stars are pretty far apart from each other.
• 18:24
  Speaker 1: We're not sort of clumped together. Yeah, exactly, and astronomically speaking,
• 18:28
  Speaker 1: astronomically speaking, and so there's gonna be very few or
• 18:31
  Speaker 1: probably zero direct collisions. You know, where one star like
• 18:34
  Speaker 1: actually slams into another one, you get stellar explosions. I mean,
• 18:38
  Speaker 1: that would be pretty awesome. I would pay for front
• 18:40
  Speaker 1: road seat, but I think it's pretty unlikely that's going
• 18:43
  Speaker 1: to happen. But you know, there's a hundred billion stars
• 18:46
  Speaker 1: running into a hundred billion other stars. Surely some of
• 18:49
  Speaker 1: them are going to hit head on, isn't it. Aren't they?
• 18:52
  Speaker 1: I mean, there's always a non zero probability, and you
• 18:54
  Speaker 1: could get lucky you're unlucky, depending on which which outcome
• 18:57
  Speaker 1: you're rooting for. But if they're diffuse enough, right, they're
• 19:00
  Speaker 1: they're far enough apart, then then all of them could
• 19:03
  Speaker 1: pass through without hitting. I mean, I think probably the
• 19:05
  Speaker 1: most likely scenarios that maybe you get one. The stars
• 19:08
  Speaker 1: also don't have to hit directly to affect each other. Right.
• 19:10
  Speaker 1: Each one is a big blob of mass, which means
• 19:13
  Speaker 1: it has gravity, and so they can jostle each other.
• 19:15
  Speaker 1: I mean, if another star came by and near our
• 19:18
  Speaker 1: Solar System and pass nearby, it could affect the orbits
• 19:21
  Speaker 1: of all the planets, like nudge a planet out of orbit.
• 19:24
  Speaker 1: Didn't have to hit the star directly head on or
• 19:27
  Speaker 1: to affect our lives. It could maybe pull us out
• 19:29
  Speaker 1: of orbit or sunk us into that other star. That's right, Um,
• 19:34
  Speaker 1: it could it could steal planets right exactly. Or um,
• 19:38
  Speaker 1: one of our planets could get ejected out of the
• 19:39
  Speaker 1: Solar System right, or it could even kick our star
• 19:43
  Speaker 1: out of the galaxy. Our star is in orbit around
• 19:46
  Speaker 1: the center of the galaxy, right, and if it comes,
• 19:48
  Speaker 1: if another star comes near enough, it could get pulled
• 19:51
  Speaker 1: and so that it gets you out of that orbit, right.
• 19:54
  Speaker 1: And orbit is sort of a delicate thing. You have
• 19:56
  Speaker 1: to be the right radius and the right velocity for
• 19:58
  Speaker 1: it all to work and start going to fast and
• 20:00
  Speaker 1: you each escape velocity. And our star could even get
• 20:03
  Speaker 1: kicked out of the galaxy. So we could be you know,
• 20:06
  Speaker 1: sort of evicted from the Milky Way, floating in intergalactic space,
• 20:10
  Speaker 1: just our star with the planets and everything. Oh, I see.
• 20:13
  Speaker 1: So when two galaxies collided, it's not it's not we
• 20:16
  Speaker 1: don't have to worry about things running into each other.
• 20:19
  Speaker 1: But it is going to be pretty chaotic, right, Like,
• 20:21
  Speaker 1: suddenly there's going to be you know, twice the number
• 20:23
  Speaker 1: of stars, and that's just going to change everything, right, yeah, exactly,
• 20:27
  Speaker 1: So things that definitely get mixed up. The stars won't
• 20:29
  Speaker 1: necessarily smash into each other, but it definitely mix each
• 20:32
  Speaker 1: other up and disturb each other. So are they are
• 20:36
  Speaker 1: these two messages going to kind of go towards each other,
• 20:39
  Speaker 1: makes a little bit and then keep going, or are
• 20:41
  Speaker 1: they you know, slamming to each other and then become
• 20:44
  Speaker 1: this giant mega galaxy. It depends a little bit on
• 20:47
  Speaker 1: their relative velocity. If they're going fast enough relative to
• 20:50
  Speaker 1: each other, then they'll pass through each other, right, But
• 20:53
  Speaker 1: if if they're not, and it doesn't seem like they are,
• 20:55
  Speaker 1: the most like scenario is that they merge, that they
• 20:58
  Speaker 1: come together and there's a little bit of slashing or whatever,
• 21:01
  Speaker 1: but eventually becomes one big galaxy. But wait, what does
• 21:04
  Speaker 1: that mean? It's like the other stars and from the
• 21:07
  Speaker 1: other galaxy. They're gonna come, but then they're going to
• 21:08
  Speaker 1: kind of go pass us a little bit, and then
• 21:10
  Speaker 1: they're gonna get pulled back in kind of thing like
• 21:12
  Speaker 1: it's gonna like a giant jelly out in space, like
• 21:15
  Speaker 1: it's going to go move, you know what I mean,
• 21:16
  Speaker 1: but in slow motion, yeah, or sort of like things
• 21:18
  Speaker 1: getting flushed down the toilet. You know, they come closer
• 21:21
  Speaker 1: and closer and closer and circle each other faster and faster.
• 21:26
  Speaker 1: You know, where we might circle each other, the two galaxies, Yeah,
• 21:29
  Speaker 1: and sort of a wall being on top of each other,
• 21:31
  Speaker 1: you know, so coming together pass a little the centers
• 21:34
  Speaker 1: of mass might pass a little bit and then turn
• 21:36
  Speaker 1: and come the other direction and spin it faster and
• 21:39
  Speaker 1: faster until the center is a massive line. So being
• 21:41
  Speaker 1: flushed down the toilet. That doesn't doesn't sound pleasant. Like
• 21:44
  Speaker 1: that doesn't sound like it's going to be easy, do
• 21:46
  Speaker 1: you know what I mean? Like, it doesn't sound like
• 21:47
  Speaker 1: it's going to uh leave us unscathed. It might, though,
• 21:51
  Speaker 1: you know, our sun could be totally fine, and it
• 21:53
  Speaker 1: could be that the planets are not distorted, their orbits
• 21:56
  Speaker 1: are not distorted, and we could just have a front
• 21:58
  Speaker 1: row seat to a pretty amazing event. And the other
• 22:01
  Speaker 1: thing is that we see this happening all the time.
• 22:03
  Speaker 1: Like you look out into space with the hubble zoom
• 22:05
  Speaker 1: in on other galaxies. There's lots of galaxies out there,
• 22:08
  Speaker 1: and lots of them are in state various stages of emerging.
• 22:11
  Speaker 1: And you can see galaxies that are just starting to merge.
• 22:14
  Speaker 1: You can see galaxies that have been merging for a
• 22:16
  Speaker 1: billion years. You can see galaxy that obviously merged a
• 22:19
  Speaker 1: long time ago. And there's sort of like an uncomfortable
• 22:22
  Speaker 1: blob of two galaxies, like one spiral arms sort of
• 22:25
  Speaker 1: knocked off over here and there's another one over there.
• 22:27
  Speaker 1: And so we have a lot of catalogs of examples
• 22:30
  Speaker 1: of galaxies that have mergy. That's how we know so
• 22:32
  Speaker 1: much about it. Yeah, if you look at there's a
• 22:33
  Speaker 1: bunch of crashes that you can study. Yeah, exactly. So
• 22:36
  Speaker 1: you want to know what galaxy collisions look like, you
• 22:38
  Speaker 1: don't have to build a galaxy collider. This is one
• 22:40
  Speaker 1: thing I love about astronomy. You have to google. You
• 22:43
  Speaker 1: can just that's right, cosmic googling, otherwise known as telescopes. Um.
• 22:48
  Speaker 1: You just look out into space and eventually you will
• 22:51
  Speaker 1: see that thing happening, like you want to imagine some
• 22:53
  Speaker 1: crazy scenario, or this kind of galaxy hits that kind
• 22:56
  Speaker 1: of galaxy, and then from behind comes a third one
• 22:58
  Speaker 1: that's happening somewhere out there there and you just need
• 23:00
  Speaker 1: to find it and watch it. And so that's the
• 23:02
  Speaker 1: amazing thing about astronomy is that all these cosmic experiments
• 23:05
  Speaker 1: are happening. We just need to look for them. Okay,
• 23:09
  Speaker 1: well we process that. Let's say, let's take a quick break,
• 23:24
  Speaker 1: all right, So that's what might happen to the stars
• 23:27
  Speaker 1: in the galaxy. What's going to happen to all these
• 23:29
  Speaker 1: other parts of the galaxy when these two galaxies collide, right?
• 23:33
  Speaker 1: And I like that we started with the stars because
• 23:35
  Speaker 1: that's like the most important thing to us, because we're
• 23:37
  Speaker 1: sort of staro centric, right, because we think stars are
• 23:40
  Speaker 1: most the most important element of the galaxy. But the
• 23:42
  Speaker 1: biggest element of the galaxy, remember, is dark matter. And
• 23:45
  Speaker 1: so you might ask, well, what's going to happen to
• 23:46
  Speaker 1: all our dark matter? And just like with the stars,
• 23:49
  Speaker 1: what what happens there depends on how much it interacts. Currently,
• 23:53
  Speaker 1: we don't really know anything about how much dark matter interacts.
• 23:56
  Speaker 1: We know that it doesn't interact with normal matter. We
• 23:59
  Speaker 1: think it doesn't interact with itself, or if it does,
• 24:00
  Speaker 1: it doesn't interact very strongly and so, but it does
• 24:03
  Speaker 1: have gravitational attraction. So if the galaxies are are going
• 24:07
  Speaker 1: to hit each other and they're not moving too fast
• 24:09
  Speaker 1: that they just basically pass right through each other, then
• 24:12
  Speaker 1: the gravity from dark matter is going to affect the
• 24:15
  Speaker 1: gravity from the other galaxies dark matter just the same
• 24:17
  Speaker 1: way the stars are, and the two will sort of
• 24:20
  Speaker 1: merge eventually become one big dark matter halo. And it's
• 24:23
  Speaker 1: the kind of thing I would love to watch, but
• 24:25
  Speaker 1: you can't really see the dark matter. It could be
• 24:27
  Speaker 1: just another version of the cluster of stars. You know.
• 24:30
  Speaker 1: It's like one blob goes into the other blob and
• 24:33
  Speaker 1: then they kind of slash around and then just becomes
• 24:35
  Speaker 1: a bigger blob. Yeah, you can think of the stars.
• 24:38
  Speaker 1: It's sort of like a collisionless liquid, right, It's like
• 24:41
  Speaker 1: a you have a liquid of stars that don't interact
• 24:44
  Speaker 1: with each other the same way the dark matter does.
• 24:45
  Speaker 1: So dark matter in stars are basically operating this under
• 24:49
  Speaker 1: the same principles. The only relevant interaction that we know
• 24:51
  Speaker 1: about is gravity, So everything we said about stars is
• 24:54
  Speaker 1: also going to affect the big blobs of dark matter.
• 24:56
  Speaker 1: The dark matter is much more continuous. We think it's smooth.
• 25:00
  Speaker 1: It's not like there's just dots of it here and there.
• 25:02
  Speaker 1: But because it hardly interacts with each other, it doesn't
• 25:04
  Speaker 1: matter if it rams smack into itself. Right, It mainly
• 25:08
  Speaker 1: affect is gravitational. It may not interact with itself. It
• 25:12
  Speaker 1: could just pass by itself and not really kind of
• 25:15
  Speaker 1: explode or collide or do anything besides pull itself gravitationally. Yeah, exactly.
• 25:20
  Speaker 1: And we don't even know what dark matter is made out,
• 25:22
  Speaker 1: so we can't say things like dark runner particles can
• 25:24
  Speaker 1: do this. Dark matter as far as we know, it's
• 25:26
  Speaker 1: just smooth, collisionless blob of something. And we know it
• 25:30
  Speaker 1: has gravitational interactions, and that's really about all we know
• 25:33
  Speaker 1: about it. So we think that that that's what's going
• 25:35
  Speaker 1: to happen. And you know, we've seen dark matter in
• 25:38
  Speaker 1: these gravitational collisions and we see that it basically sticks
• 25:41
  Speaker 1: with the galaxies, right, it sticks with the stars. Okay,
• 25:45
  Speaker 1: so then the last part is the black hole at
• 25:47
  Speaker 1: the center of each galaxy. What no, no, don't forget
• 25:50
  Speaker 1: the dust, right, this gas dust, which a lot of
• 25:52
  Speaker 1: people overlook, and this is actually the most exciting part
• 25:55
  Speaker 1: because the dust is the most the coolest part. That's
• 26:00
  Speaker 1: how you know you're listening to a nerdy podcast and
• 26:02
  Speaker 1: they get excited about dust. Oh my god. You know
• 26:06
  Speaker 1: if if for those people who are like expecting dramatic
• 26:09
  Speaker 1: events and explosions, this is where you get them. Okay,
• 26:12
  Speaker 1: because dust is not diffuse, right's spread everywhere, Like you
• 26:16
  Speaker 1: have a big blob of dust. It's not like little
• 26:19
  Speaker 1: clusters of mass the way stars are. It's a huge
• 26:22
  Speaker 1: extended blob of dust. And when it smashes into another
• 26:25
  Speaker 1: blob of dust, you're going to get fireworks. Like those
• 26:29
  Speaker 1: clouds of dust interact with each other the way dark
• 26:31
  Speaker 1: matter doesn't. And they're um spread everywhere the way stars aren't,
• 26:36
  Speaker 1: and so you get huge collisions. And what happens when
• 26:39
  Speaker 1: you compress gas and dust. What happens when you collide
• 26:41
  Speaker 1: huge blobs of gas and dust is you get more
• 26:44
  Speaker 1: dense and then you get stars. And so you could
• 26:47
  Speaker 1: see like new stars being born where these two huge
• 26:51
  Speaker 1: clouds of gas and dust being into each literally like fireworks.
• 26:55
  Speaker 1: Like that's right, cosmic fireworks. I mean, what's more are
• 27:00
  Speaker 1: dramatic and what's a better cosmic firework than seeing stars
• 27:03
  Speaker 1: be born? Yeah, so this one is going to be
• 27:05
  Speaker 1: like to you know, you know, two liquids kind of
• 27:08
  Speaker 1: running into each other. It is going to be kind
• 27:10
  Speaker 1: of dramatic, you know, like it is going to be
• 27:12
  Speaker 1: like with the sound effects and everything in space. No, yeah, exactly,
• 27:19
  Speaker 1: It's just like two water balloons hitting each other. Right,
• 27:21
  Speaker 1: You're gonna get an initial shop wave. And you know,
• 27:24
  Speaker 1: you don't get stars born when you fire water balloons
• 27:26
  Speaker 1: at each other because the density isn't great enough obviously,
• 27:28
  Speaker 1: But yeah, you're gonna get a shock wave. You're gonna
• 27:30
  Speaker 1: get friction between the fluids, and you're going to get
• 27:32
  Speaker 1: stars being born. It's gonna be pretty dramatic. So you
• 27:36
  Speaker 1: don't want to be there. You don't want to want
• 27:37
  Speaker 1: to But we are, aren't We surrounded by gas clouds
• 27:40
  Speaker 1: and stuff? Oh? I think you need denser stuff. I mean,
• 27:43
  Speaker 1: the milky wave definitely has big clouds of gas and dust.
• 27:46
  Speaker 1: Oh I see, But when those clouds running to the
• 27:48
  Speaker 1: other clouds, then that's where this stuff happens. But we're
• 27:51
  Speaker 1: not necessarily sitting in one of those clouds. That's right, yeah, okay,
• 27:58
  Speaker 1: the last element is the black hole, right, and so
• 28:01
  Speaker 1: our galaxy is a huge black hole the center, and
• 28:03
  Speaker 1: the other guy, almost every other galaxy is a huge
• 28:05
  Speaker 1: black hole of the center. And there it's gonna be
• 28:08
  Speaker 1: mostly dominated by gravity, right, because they're gonna pull each
• 28:12
  Speaker 1: on each other really hard, and they're gonna pass by
• 28:15
  Speaker 1: each other a little bit, perhaps because they're probably not
• 28:17
  Speaker 1: gonna hit dead on and then they're gonna swing around.
• 28:20
  Speaker 1: They're gonna pull on each other, so they'll probably be
• 28:22
  Speaker 1: you know, some sort of a near miss, and then
• 28:24
  Speaker 1: they'll turn around and come back. And then they'll just
• 28:27
  Speaker 1: circle each other faster and faster and faster. And if
• 28:30
  Speaker 1: you remember the episode we did on gravitational waves, or
• 28:33
  Speaker 1: if you've heard about the discovery of gravitational waves, you
• 28:36
  Speaker 1: know that what happens when black holes get close to
• 28:38
  Speaker 1: each other as they start to circle each other faster
• 28:40
  Speaker 1: and faster, until eventually they spend really really fast and
• 28:44
  Speaker 1: the distance get closer and closer and closer, and then
• 28:46
  Speaker 1: they merge and they become one enormous black hole. They
• 28:48
  Speaker 1: like eat each other, right, But and it's not a
• 28:52
  Speaker 1: peaceful event it's like a pretty violent thing, right, Like
• 28:55
  Speaker 1: they've been super super fast, there's energy spewed out everywhere,
• 28:58
  Speaker 1: and then suddenly have these huge cataclysmic gravitational waves. Oh yeah,
• 29:03
  Speaker 1: when black holes fight, it's a big mess. Absolutely. You
• 29:05
  Speaker 1: don't want to be anywhere near that because huge amounts
• 29:09
  Speaker 1: of radiation, not just gravitational waves. Right, yeah, you make
• 29:11
  Speaker 1: gravitational waves, which are pretty awesome from a physics point
• 29:14
  Speaker 1: of view, but you know, these things tear up into
• 29:16
  Speaker 1: each other and amid huge amounts of radiation, and so
• 29:19
  Speaker 1: you don't want to be anywhere near that. Yeah, I
• 29:20
  Speaker 1: mean that that's gonna like sterilize life on any nearby
• 29:23
  Speaker 1: star system for sure. But anyway, there probably isn't any
• 29:26
  Speaker 1: life in the center of art galaxy for that same
• 29:28
  Speaker 1: reason that the galactic black hole is already emitting huge
• 29:31
  Speaker 1: amounts of life killing radiation, so you don't want to
• 29:33
  Speaker 1: get too close anyway. It's like the eye of a storm.
• 29:35
  Speaker 1: There's nothing living in the middle of it, that's right.
• 29:38
  Speaker 1: I don't know if it's calm inside the black hole.
• 29:41
  Speaker 1: That we did a whole episode actually on what it's
• 29:42
  Speaker 1: like to be inside a black hole. So you guys
• 29:44
  Speaker 1: should go listen to that. But yeah, it's a it's
• 29:46
  Speaker 1: everything is swirling around that central black hole. And so
• 29:48
  Speaker 1: probably what will happen is they'll merge and the new milk,
• 29:51
  Speaker 1: the new galaxy. I wonder what that galaxy would be called. Actually,
• 29:55
  Speaker 1: how would you combine and Rameda in the Milky Way,
• 29:57
  Speaker 1: like Drama Dinky Way, milk milk Drameda, I don't know,
• 30:04
  Speaker 1: and ramedaway the Andromeda Away. There you go, the Andromeda Way. Yeah,
• 30:09
  Speaker 1: the new galaxy would have a huge, super duper massive
• 30:14
  Speaker 1: black hole at its center. Yeah, and so I think
• 30:16
  Speaker 1: that basically sums it up. You'd have the black holes
• 30:19
  Speaker 1: will probably emerge huge violent eruption of radiation there gas
• 30:24
  Speaker 1: and the dust would have a lot of friction caused
• 30:26
  Speaker 1: caused star formation, big explosion, bigion work, Yeah, exactly. Friction, Yeah,
• 30:31
  Speaker 1: just all the kind of stuff you expect to see
• 30:33
  Speaker 1: in the next Transformers movie. And then stuff. He'll be there,
• 30:38
  Speaker 1: He'll be there everything. If there's money to be made,
• 30:42
  Speaker 1: he'll be there. Um. And then the stars and the
• 30:46
  Speaker 1: dark matter will just have a gravitational effect, but they'll
• 30:49
  Speaker 1: know eventually settle down and in a few more billion years,
• 30:52
  Speaker 1: the new galaxy will have its own shape. It will
• 30:55
  Speaker 1: sort of settle into its own new shape. But it
• 30:57
  Speaker 1: kind of sounds like every part will do something. Friend,
• 31:00
  Speaker 1: do you know what I mean? Yeah, they will because
• 31:01
  Speaker 1: they follow different rules, right, they interact differently and so
• 31:04
  Speaker 1: but so, then kind of the nice structure we have
• 31:07
  Speaker 1: now is going to be pretty much obliterated right when
• 31:09
  Speaker 1: it we're just with the other one. Yeah, exactly. You
• 31:11
  Speaker 1: shouldn't count on your real estate being the same value.
• 31:14
  Speaker 1: After the galaxy collision, Everything's going to be shook up, right, Absolutely,
• 31:18
  Speaker 1: it's going to be disrupt the entire Both galaxies gonna
• 31:21
  Speaker 1: be totally disrupted. Fireworks collisions. But you're saying it's possible
• 31:26
  Speaker 1: we may survive it, right, that it's possible nothing will
• 31:29
  Speaker 1: actually happen to our solar system. I think that's the
• 31:31
  Speaker 1: most likely outcome. Yeah, is it will just be sort
• 31:33
  Speaker 1: of interesting likely, Yeah, most likely most likely thing. I mean,
• 31:37
  Speaker 1: we're a star. We were basically part of our star,
• 31:40
  Speaker 1: right you think of the Solar system is just one
• 31:41
  Speaker 1: big blob, And the most likely thing is that nothing
• 31:44
  Speaker 1: gets close enough to disrupt our orbit around the star.
• 31:47
  Speaker 1: And you know what, even if our star gets like
• 31:49
  Speaker 1: ejected from the galaxy. So what we don't need the galaxy.
• 31:53
  Speaker 1: We could live just fine, just a star with a
• 31:55
  Speaker 1: bunch of planets in the middle of intergalactic space. We
• 31:57
  Speaker 1: don't need anything else. We just never start to provide
• 32:00
  Speaker 1: energy for life. So so we don't mean just in
• 32:03
  Speaker 1: the same way we're talking about the beginning of the episode,
• 32:05
  Speaker 1: like you don't really notice what's going out in space
• 32:07
  Speaker 1: because you don't usually have to. And if all those
• 32:10
  Speaker 1: if all those stars disappeared and all we and we
• 32:12
  Speaker 1: were in the middle of intergalactic space, it wouldn't change
• 32:15
  Speaker 1: your life at all. You would still still need to
• 32:17
  Speaker 1: stock up on lentils for the coming Apoco lips. You know,
• 32:20
  Speaker 1: it wouldn't save you or change your plans at all.
• 32:22
  Speaker 1: You wouldn't mind getting kicked out of town like that.
• 32:24
  Speaker 1: That's kind of what it would feel like, like the
• 32:27
  Speaker 1: whole town, our whole town. We just get kicked out,
• 32:29
  Speaker 1: you know, and we just go on living the way
• 32:31
  Speaker 1: what we did before. But things will definitely change for
• 32:35
  Speaker 1: us even if we survived it's galactic collision, the night
• 32:38
  Speaker 1: sky will look very different. I mean, as Andromeda approaches
• 32:41
  Speaker 1: in the next few billion years, it will grow in
• 32:44
  Speaker 1: the sky and eventually look really big. And then after
• 32:47
  Speaker 1: the collision, right when things have settled down, the night
• 32:49
  Speaker 1: sky would look totally different because all the stars will
• 32:51
  Speaker 1: have been rearranged and we won't see that band in
• 32:53
  Speaker 1: the milky Way anymore. Well, that makes me feel better.
• 32:57
  Speaker 1: I was sweating. I was sweating what was gonna happen
• 32:59
  Speaker 1: for and I have been years from now. But now
• 33:01
  Speaker 1: now I feel better and I and I hope Blake
• 33:04
  Speaker 1: you also feel a little bit better. Yeah, that's right, Bake,
• 33:06
  Speaker 1: chill out, don't worry about it. Um, you have nothing
• 33:08
  Speaker 1: to worry about. I think it's fun to think about
• 33:16
  Speaker 1: things happening deep into the future, and also even further
• 33:19
  Speaker 1: into the future. You know, the universe has been around
• 33:22
  Speaker 1: fourteen billion years, right, and that's just sort of like
• 33:25
  Speaker 1: the initial bits, not before we get to the interesting part.
• 33:28
  Speaker 1: But it could be they were not even at the
• 33:30
  Speaker 1: interesting part. You know. Thinking about galaxies in this way
• 33:33
  Speaker 1: reminds you that they're spinning their dynamic, they're swirling around
• 33:36
  Speaker 1: each other. What's going to happen? We don't know, right,
• 33:39
  Speaker 1: they could continue to swirl and form crazy new structures
• 33:43
  Speaker 1: that know, the universe has never seen before. Because there
• 33:45
  Speaker 1: hasn't been time to make them. And so this is
• 33:48
  Speaker 1: the kind of thing makes me think about the universe,
• 33:49
  Speaker 1: like on the trillion or two trillion life year cycle,
• 33:53
  Speaker 1: Like if life is still around ten trillion years into
• 33:56
  Speaker 1: the history of the universe, they'll think about these first
• 33:59
  Speaker 1: few moments of lactic formation as you know, almost irrelevant,
• 34:03
  Speaker 1: just like just warming up. The best maybe yet to come. Now,
• 34:08
  Speaker 1: that's right. I'm an optimistic person, so I'm always hoping
• 34:11
  Speaker 1: that the best thing is yet to come. Exactly well, great, um,
• 34:14
  Speaker 1: thank you so much Bla for sending us this question.
• 34:16
  Speaker 1: We really enjoyed answering it. That's right. And check out
• 34:19
  Speaker 1: our book called We Have No Idea. It's a guide
• 34:22
  Speaker 1: to the unknown questions of the universe, all the things
• 34:24
  Speaker 1: that physics wants to know the answer to but really
• 34:26
  Speaker 1: hasn't got a clue about. And thanks for listening. Yeah,
• 34:30
  Speaker 1: and if you're hungry or want to stuck up, just
• 34:32
  Speaker 1: don't forget to get Daniel's Spicy lentils, now available at
• 34:39
  Speaker 1: your local grocery store. If you still have a question
• 34:49
  Speaker 1: after listening to all these explanations, please drop us a line.
• 34:52
  Speaker 1: We'd love to hear from you. You can find us
• 34:54
  Speaker 1: at Facebook, Twitter, and Instagram at Daniel and Jorge That's
• 34:58
  Speaker 1: one Word, or smail us at Feedback at Daniel and
• 35:02
  Speaker 1: Orge dot com. H m hm