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Speaker 1: Hey or hey, I have a physics version of would

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Speaker 1: you rather?

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Speaker 2: Well, oh, I'd rather not play?

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Speaker 1: Not an option today? So would you rather be blown

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Speaker 1: up in a supernova or crushed in a black hole?

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Speaker 2: Well, if I fell into a black hole, there would

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Speaker 2: be time dilation, so it sounds like it would take forever.

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Speaker 2: So maybe I'll go with a supernova, nice and quick.

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Speaker 1: All right? Next one, would you rather be eaten by

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Speaker 1: aliens or live your life never knowing if aliens exist?

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Speaker 2: I would pick live my life over and being eaten

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Speaker 2: by anything, aliens or otherwise.

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Speaker 1: Wrong answer, wrong answer. Next one, would you rather keep

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Speaker 1: playing this game or start the podcast?

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Speaker 2: I'll pick the supernova again. Please, I'm crushed just trying

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Speaker 2: to blow this up.

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Speaker 1: Hi.

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Speaker 2: I'm hoorhamy cartoonist and the creator of PhD comics.

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Speaker 1: Hi I'm Daniel. I'm a particle physicist and a professor

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Speaker 1: at UC Irvine, and I would rather be eaten by

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Speaker 1: aliens than never know if they exist for real.

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Speaker 2: Well, I guess if you get do you get to

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Speaker 2: choose when you get eaten by aliens? You know, if

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Speaker 2: you can choose to get it done right before you're

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Speaker 2: gonna die of natural causes. Maybe that's okay, but like

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Speaker 2: right now, you would make that choice right now.

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Speaker 1: I think this game is all about those loopholes, like

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Speaker 1: when people are planning for end of life, like do

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Speaker 1: you want to get buried or do you want to

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Speaker 1: get cremated. I'm going to fill out a box that

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Speaker 1: says I want to get eaten by aliens. But yeah,

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Speaker 1: it'd be nice if they waited till after I already

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Speaker 1: died of natural causes. Then you know, hey, barbecue me

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Speaker 1: for the alien pot luck. That's fine.

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Speaker 2: You gotta be careful, though, do you mean like extraterrestrial

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Speaker 2: aliens or people who are you know, alien alien to

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Speaker 2: your life or to your city?

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Speaker 1: You know what, I'm not gonna be around, so I

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Speaker 1: guess it doesn't really matter.

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Speaker 2: Oh you're gonna be around as you're getting in.

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Speaker 1: As long as I get to learn about the aliens

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Speaker 1: while I'm still alive, nothing else really matters.

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Speaker 2: Oh boy. Anyways, Welcome to our podcast Daniel and Jorge

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Speaker 2: Explain the Universe, a production of iHeartRadio in which.

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Speaker 1: We take great pains and great sacrifices to try to

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Speaker 1: explain the nature of the universe to you. We cast

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Speaker 1: our minds out into that dark cosmic mystery and wonder

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Speaker 1: what's out there, who's out there, what's going on out there,

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Speaker 1: how big is it? Is it still sloshing around, and

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Speaker 1: what will be its final fate. We want to understand

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Speaker 1: the cosmic context of our very existence because it drives

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Speaker 1: the choices we make every day about whether or not

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Speaker 1: we sign ourselves up to be part of an alien barbecue.

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Speaker 2: That's right. It is a humongous universe full of amazing

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Speaker 2: and awesome things out there that may kill you or

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Speaker 2: eat you, and or inspire you to learn more about

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Speaker 2: the universe and the cosmos and how everything works in it.

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Speaker 1: And it's part of this sort of incredible mental history,

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Speaker 1: the trajectory of our sort of mental map of the cosmos.

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Speaker 1: You know, it started out pretty small, your little village,

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Speaker 1: your neighborhood, eventually expanded to be a larger and larger region.

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Speaker 1: Finally people started incorporating the cosmos into it, this mental

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Speaker 1: picture of the whole universe that we were in. But

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Speaker 1: it just gets bigger and bigger as we understand where

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Speaker 1: our solar system sits and where our galaxy sits, and

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Speaker 1: as our telescopes get more and more powerful, we can

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Speaker 1: now understand even further the context of our cosmic neighborhood.

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Speaker 2: Yeah, it used to be there. Our context was pretty

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Speaker 2: much like the Earth, and people thought that the Sun

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Speaker 2: and the moon and the stars all revolved around the Earth.

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Speaker 2: People thought that the entire universe was just us.

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Speaker 1: Yeah. I was reading about ancient Chinese astronomy and they

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Speaker 1: even calculated like how far away the stars were. They

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Speaker 1: thought it was something like twenty seven thousand miles above

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Speaker 1: the Earth.

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Speaker 2: Oh, that's pretty close.

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Speaker 1: And the Greeks thought that everything moved in like literal

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Speaker 1: crystal spheres around the Earth. That was the original ether.

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Speaker 2: Interesting, now, Daniel, do we know for sure that's not true?

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Speaker 2: Do you know for sure that's not true.

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Speaker 1: I mean, we've sent probes out there to visit these things,

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Speaker 1: so we're pretty sure there are no crystal spheres out

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Speaker 1: there moving the planets.

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Speaker 2: By we mean the perverurial we but have you gone

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Speaker 2: up there and touched these that made sure there's no

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Speaker 2: crystal spheres.

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Speaker 1: I'm going to take NASA's word for it, you know,

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Speaker 1: for sure. I'm not part of the conspiracy community that

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Speaker 1: thinks NASA's been lying to us all these years.

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Speaker 2: You know, part of the crystal sphere conspiracy.

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Speaker 1: I'm sure there's a group of crystal truthists out there.

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Speaker 2: You know, part of the China was right theory.

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Speaker 1: No, but the Chinese did make a lot of really

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Speaker 1: amazing observations. You know, we have like records of eclipses

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Speaker 1: dating back foulands of years from China and observations is

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Speaker 1: like super nova from almost a thousand years ago. So

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Speaker 1: it's a really rich history of astronomical observations, some of

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Speaker 1: which are still relevant to our studies today. Is incredible.

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Speaker 2: Oh, it's pretty cool. Yeah, because, as you were saying,

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Speaker 2: our understanding of where or and how we fit in

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Speaker 2: this universe keeps growing and growing, and it seems like

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Speaker 2: each time we just get more and more insignificant with

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Speaker 2: each step.

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Speaker 1: But we become more and more aware of that significance,

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Speaker 1: which makes us sort of like philosophically more important. Right,

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Speaker 1: We're like incorporating more of the universe into our minds.

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Speaker 2: No, that makes no sense. We're insignificant specs in this

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Speaker 2: giant universe.

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Speaker 1: But it's better to know about your insignificance because then

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Speaker 1: you've gained some philosophical stature.

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Speaker 2: Like being know where you're being in by aliens doesn't help.

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Speaker 2: The fact that you're being eaten by.

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Speaker 1: Eight still makes it worth. It still makes it worth.

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Speaker 2: In fact, that makes it worse. But it does seem

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Speaker 2: like we are getting smaller and smaller in the sumer

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Speaker 2: And literally that's true, right because every year, every second

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Speaker 2: of the day, the universe, or our understanding of how

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Speaker 2: big it is, keeps getting bigger.

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Speaker 1: Right, it does. And even though we cannot explore the

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Speaker 1: far flung edges of the observable universe, we can build

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Speaker 1: this mental model, this sort of map of our neighborhood

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Speaker 1: that tells us where we are in this glittering cosmos.

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Speaker 1: And so even though no human will probably visit those

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Speaker 1: planets or visit those stars, we can still tell you

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Speaker 1: something about what's going on out there. And to me

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Speaker 1: that's incredible. Yes, we are probably trapped on this rock

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Speaker 1: or our neighboring rocks, but still we can build this

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Speaker 1: map of the cosmos, we can understand something about it.

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Speaker 1: And to me, that's a great achievement sort of intellectually

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Speaker 1: and scientifically, and what I'm pretty proud of.

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Speaker 2: Yeah, again, I think you're using the proverbial we there,

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Speaker 2: you're proud of the work of others. Let's be honest here.

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Speaker 1: No, I'm standing on the shoulders of many, many giants,

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Speaker 1: and I'm proud of their work. Absolutely, I'm not personally

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Speaker 1: taking credit for our understanding of the universe in case

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Speaker 1: anybody misunderstood, But.

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Speaker 2: At least we're helping, I guess talk about what they've

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Speaker 2: done and disseminate this information out to others. And it's

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Speaker 2: interesting when you say like that we might never reach

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Speaker 2: those places that we're seeing far far away. I'm wonder

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Speaker 2: if that's really true. I guess that's true because our

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Speaker 2: view of the universe expanding at the speed of light,

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Speaker 2: and there's no way that humans could outpacete that. Right.

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Speaker 1: Yeah, it's amazing we can see things that are moving

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Speaker 1: away from us faster than the speed of light. A

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Speaker 1: bunch of listeners wrote in and asked, like, how does

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Speaker 1: that work? We have a whole episode covering it, but briefly,

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Speaker 1: the thing to understand when you're looking at an object

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Speaker 1: and they tell you, oh, this thing is thirty billion

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Speaker 1: years away and it's moving away from us faster than

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Speaker 1: the speed of light, is that you're not seeing it

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Speaker 1: where it is now. They're telling you where it is now.

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Speaker 1: But you're seeing the light that was emitted from it

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Speaker 1: when it was much much closer. So it used to

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Speaker 1: be much closer, and it's sent a photon our way.

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Speaker 1: In the meantime, it's moved really really far away. When

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Speaker 1: they say here, we're looking at a galaxy that's really

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Speaker 1: really far away, we're not seeing light that came to

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Speaker 1: us from it when it was that far away. Were

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Speaker 1: seeing light that came to us when it was much

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Speaker 1: much closer. Light that leaves it now we will never see,

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Speaker 1: which means also we will never visit it.

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Speaker 2: Mmm. Yeah, Because the universe is expanding faster and faster

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Speaker 2: every time, every second of the day. Although we don't

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Speaker 2: know what's going to happen in the future right, it

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Speaker 2: could be that in the far distant future or maybe tomorrow,

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Speaker 2: the universe might decide, Hey, I think I'm going to

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Speaker 2: stop growing and I'm going to collapse back on myself,

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Speaker 2: and in which case, we're going to basically visit every

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Speaker 2: place in the universe at some point.

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Speaker 1: Yeah, or they're going to come visit us and they're

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Speaker 1: going to bring with them all their aliens, with all

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Speaker 1: their barbecue.

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Speaker 2: Tools, all their appetites. Well, maybe the big joke is

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Speaker 2: that in the end, the universe eats us.

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Speaker 3: All.

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Speaker 1: Well, we are the universe, so I guess the universe

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Speaker 1: eats itself. I'm not sure how that works.

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Speaker 2: Whoa dude.

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Speaker 1: And even though we are learning that we are a

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Speaker 1: tiny speck in a vast, vast cosmos, I think it

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Speaker 1: does make us sort of like philosophically or intellectually more

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Speaker 1: powerful to have grappled with that vast cosmos. It's better

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Speaker 1: at least than being ignorant of what's going on right right?

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Speaker 2: But don't they say ignorance is bliss Sometimes?

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Speaker 1: Who's looking for bliss? Man, I'm looking for knowledge.

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Speaker 2: Maybe that's the difference between you and me and Daniel.

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Speaker 2: I'll go for bliss any day.

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Speaker 1: Okay, Well, I'm glad we can split the tasks. But

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Speaker 1: it's also fun to think about that far future you

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Speaker 1: were talking about and wondering, like, what does the future hold?

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Speaker 1: Will our solar system survive for our billion years? Will

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Speaker 1: our galaxy survive for ten billion years? What exactly is

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Speaker 1: going to happen to our cosmic neighborhood over cosmic deep time? Yeah?

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Speaker 2: Because, as we mentioned, the universe is expanding faster and

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Speaker 2: faster and faster and that has some pretty dramatic consequences

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Speaker 2: for some of the bigger structures in the universe. And

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Speaker 2: so today on the podcast we'll be tackling the question

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Speaker 2: will our super cluster be torn apart? Sounds kind of sad.

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Speaker 1: Like a chunk of juicy barbecue.

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Speaker 2: Well, wow, who would eat a giant supercluster galaxies.

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Speaker 1: Some giant super space crab? I suppose, Oh boy?

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Speaker 2: And how big does the barbecue sauce bottle need to be? Well,

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Speaker 2: this is an interesting question and so we'll dig into

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Speaker 2: it of what a supercluster is, what does it mean

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Speaker 2: for it to be torn apart? And what could be

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Speaker 2: causing it to be torn apart? But as usual, we

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Speaker 2: were wondering how many people had considered these words together

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Speaker 2: as a question out there in the internet.

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Speaker 1: So thanks very much to everybody who participates in this

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Speaker 1: segment of our podcast. It's super fun for us to

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Speaker 1: hear what you're thinking about the topic of the day.

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Speaker 1: Please don't be shy. If you'd like to participate in

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Speaker 1: the future, just write to me to Questions at Danielandjorge

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Speaker 1: dot com.

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Speaker 2: So think about it for a second. Do you think

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Speaker 2: our supercluster will be torn apart. Here's what people have

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Speaker 2: to say. I say no, I believe that dark matter

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Speaker 2: and dark energy will keep it together, just like it

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Speaker 2: build the supercluster that we see today.

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Speaker 4: Well, our supercluster, if I believe right, is a collection

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Speaker 4: of galaxy that we're in kind of grouped up. So

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Speaker 4: if anything, I feel like it would get larger just

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Speaker 4: by gravitationally attracting other galaxies that are just floating out there.

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Speaker 3: If I get it right, the galaxies of our supercluster

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Speaker 3: won't drift apart due to the expansion of the universe,

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Speaker 3: but they might dive into each other.

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Speaker 5: A supercluster is a group of galaxy dark energy. Obviously

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Speaker 5: he's moving things apart. But I think the galaxy would

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Speaker 5: stay together, but that galaxies would separate from each other.

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Speaker 5: So I reckon our supercluster will be torn apart.

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Speaker 2: All right, Some people are feeling optimistic about our supercluster.

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Speaker 1: It looks like three to one for our superclusters sticking together.

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Speaker 1: We got some optimists out there.

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Speaker 2: Yeah. Yeah, everyone wants to remain I guess in the cluster.

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Speaker 1: They want to stay cozy. No one wants to blow

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Speaker 1: up our spot.

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Speaker 2: Yeah, but I guess some people mentioned gravity us together

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Speaker 2: instead of letting the supercluster get torn apart, and some

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Speaker 2: people mention dark matter as a way to keep things together.

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Speaker 1: Yeah, and the overall theme here is pretty much spot

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Speaker 1: on that the universe is in a tug of war

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Speaker 1: between gravity and dark energy and those things play out

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Speaker 1: very differently on different distances and different scales. And so

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Speaker 1: the fascinating question is like, at what point does dark

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Speaker 1: energy win? And where will gravity win?

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Speaker 2: Who will eat who? Gravity versus dark energy.

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Speaker 1: That's like Godzilla versus King Kong.

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Speaker 2: That's like slow roasted ribs versus grilled chicken.

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Speaker 1: I'll just eat them both.

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Speaker 2: Mane sounds good. Well, let's dive into this tasty topic here,

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Speaker 2: step us through Daniel. What is a supercluster of galaxies?

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Speaker 1: So a supercluster is the biggest thing in the universe.

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Speaker 1: It's the largest structure we think can exist in the universe.

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Speaker 1: And this episode is going to hinge closely on what

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Speaker 1: we mean by a structure. What is a thing in

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Speaker 1: the universe? Because you could just look out in space

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Speaker 1: and say I'm going to group all this stuff together

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Speaker 1: and call it a thing and give it a name,

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Speaker 1: the way we sort of do for constellations, But astronomers

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Speaker 1: like to think about things in the universe structures as

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Speaker 1: things that sort of hold themselves together, that have enough

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Speaker 1: gravity to be tied together to be an equilibrium. So

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Speaker 1: in our immediate neighborhood, for example, we think of the

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Speaker 1: Solar System as a thing. The Earth is going around

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Speaker 1: the Sun and it's going to keep doing that. Gravity

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Speaker 1: is holding the Earth around the Sun and all the

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Speaker 1: other planets, So we think of the Solar System as

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Speaker 1: a structure, as this gravitationally bound kind of object.

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Speaker 2: Yeah, because I guess if you think about just the

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Speaker 2: word structure and what it means in our everyday lives,

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Speaker 2: it basically just means like things that are clumped together, right,

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Speaker 2: or that move together, or that can be separated from

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Speaker 2: each other. And you sort of drill down into it,

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Speaker 2: like even the house you're sitting on, or the building

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Speaker 2: you're sitting on, or maybe even the car you're sitting on,

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Speaker 2: it's just a collection of loose parts being held together

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Speaker 2: by a force in the universe. Like they're not part

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Speaker 2: of the same thing. They're individual particles, but there's just

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Speaker 2: some force that keeps them all moving together.

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Speaker 1: Yeah, and it feels like a really natural thing. Right

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Speaker 1: to say I'm held together, I'm a thing. You're held together,

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Speaker 1: you're another thing. Even if we're standing next to each other,

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Speaker 1: it's easy to draw the line between us and say,

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Speaker 1: like where I end and you begin. That's sort of philosophically,

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Speaker 1: very straightforward, and so we imagine maybe that's possible to

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Speaker 1: do for other stuff too, Right to say, well, here's

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Speaker 1: one planet and there's another planet, to draw these lines

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Speaker 1: and say this thing holds itself together, and that thing

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Speaker 1: holds itself together. So that's sort of the idea of

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Speaker 1: a structure, But it can also get kind of fuzzy,

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Speaker 1: Like when you look up at the sky and you

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Speaker 1: see a cloud. It's this big blob of vapor. It's

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Speaker 1: not really holding itself together. I mean, it looks like

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Speaker 1: a thing sort of localized and clumped, but it's definitely

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Speaker 1: not gravitationally holding itself together. It just sort of happens

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Speaker 1: to be all in the same place at the same time,

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Speaker 1: or like a crowd in a park at lunchtime. Right,

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Speaker 1: they all happen to be near each other. They're clumped,

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Speaker 1: but they're not holding themselves together. So there can be

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Speaker 1: sometimes things that are like near each other. There are

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Speaker 1: clumps but not structures.

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Speaker 2: Interesting, Yeah, crowd is a good example, right, because it

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Speaker 2: may look like a cluster, or like from a farm,

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Speaker 2: might look like a clump of things, but really there's

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Speaker 2: nothing keeping those individual people or structures together.

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Speaker 3: Right.

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Speaker 2: They could at any moment just leave the group.

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Speaker 1: Yeah. Every kindergarten teacher knows that when you try to

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Speaker 1: take them out on a field trip, right, they can

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Speaker 1: all just suddenly run in any random direction.

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Speaker 2: Yeah, Whereas maybe like for the planet Earth, all the

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Speaker 2: rocks on planet Earth are being kept from flying away

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Speaker 2: by gravity, by a force.

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Speaker 1: And it's really fascinating to think about the sort of

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Speaker 1: levels of structure, right, Like a rock is a structure,

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Speaker 1: but it's also part of a larger structure the Earth,

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Speaker 1: and the Earth of course is a structure, but again

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Speaker 1: it's part of a larger structure. So we have this

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Speaker 1: incredible nested hierarchy of structures, which is really fascinating to

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Speaker 1: think about, like the scale of those things, right, Like

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Speaker 1: an atom is a structure, You're made of so many

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Speaker 1: structures on so many levels. Incredible to think about, like

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Speaker 1: how organized the universe is, and as a whole group

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Speaker 1: of philosophers who study this kind of thing and wonder like,

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Speaker 1: why do we have structure of these distances and not

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Speaker 1: other distances? And does it bubble up from the fundamental

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Speaker 1: laws of the universe and all sorts of fascinating philosophical

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Speaker 1: rabbit holes. But it's also just kind of fun to

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Speaker 1: figure out, like what is the structure? What is our

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Speaker 1: cosmic neighborhood, and so we can like zoom out step

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Speaker 1: by step and understand how we fit in to this

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Speaker 1: sort of larger cosmic set of like Russian nesting dolls.

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Speaker 2: Yeah, because I guess you know, sort of like you

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Speaker 2: were saying, the atoms in my body make up my structure,

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Speaker 2: but they're all also kind of being pulled by the

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Speaker 2: gravity of the earth, right, so like is it more

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Speaker 2: part of my structure or are all the atoms in

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Speaker 2: my body more part of the earth structure? And even

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Speaker 2: like the atoms in my body are being pulled by

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Speaker 2: the gravity of the sun. But we wouldn't say, like, hey,

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Speaker 2: I'm just me and the sun are one, even though

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Speaker 2: if you sort of follow the chain of forces that

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Speaker 2: we are sort of in the same structure as the Sun.

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Speaker 1: Yeah, And so you're part of many structures or you

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Speaker 1: could say that there's substructure, right, You could just look

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Speaker 1: at the whole galaxy and say the galaxy is a blob,

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Speaker 1: but obviously it has substructure. It's not just a smooth

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Speaker 1: distribution of atoms. There are stars and solar systems and

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Speaker 1: even clumps to those stars. They are like these groups

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Speaker 1: of stars are all formed together that are still moving together,

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Speaker 1: like that Kindergarten group. So there's sort of lots of

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Speaker 1: layers of structure, and it's fascinating to ask, like how

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Speaker 1: many layers are there? How many layers can we zoom

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Speaker 1: out and still see things that seem to be holding

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Speaker 1: themselves together. So we start with ourselves, and then of

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Speaker 1: course we have the Earth, and then there's the solar system,

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Speaker 1: and then we zoom out. The next sort of big

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Speaker 1: layer of structure would either be like a group of

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Speaker 1: stars that we all form together with or you would

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Speaker 1: zoom all the way out to the galaxy. Because those

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Speaker 1: groups of stars that form together, they don't really hold

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Speaker 1: themselves together for very long. They tend to disperse into

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Speaker 1: the galaxy.

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Speaker 2: M do we know that's for sure? Or I mean, like,

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Speaker 2: do we know which stars are near us? And would

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Speaker 2: you say maybe they're too far away for their gravity

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Speaker 2: to really affect us.

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Speaker 1: Yeah, other stars are too far away for the gravity

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Speaker 1: to really affect us. And we all have velocity through

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Speaker 1: the galaxy, and so we know a lot about actually

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Speaker 1: how stars dissipate from their original cluster. It can take

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Speaker 1: tens or hundreds of millions of years, but we definitely

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Speaker 1: see evidence of that when we look out at the

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Speaker 1: pattern of the stars in our galaxy. It also helps

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Speaker 1: us understand how the stars are moving. For example, like

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Speaker 1: the Big Dipper is a group of stars that were

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Speaker 1: all formed together, and they're moving together, but they're also

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Speaker 1: moving really fast and they're kind of close by, which

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Speaker 1: means that the Big Dipper is changing. You don't think

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Speaker 1: about the constellations as changing very much, but they actually

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Speaker 1: are all moving. We're not all moving at the same

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Speaker 1: relative velocity. So like the galaxy is a big, slashing

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Speaker 1: bathtub of stars. So the Big Dipper changes, and over

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Speaker 1: like one hundred thousand years or a few hundred thousand years,

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Speaker 1: the Big Dipper will no longer look like the Big Dipper.

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Speaker 2: Now are they would you say they're a structure or

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Speaker 2: are they just moving together like a crowd, or like

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Speaker 2: a wisp of clouds.

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Speaker 1: They are not a structure because they're not going to

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Speaker 1: hold themselves together. They're not like tight enough to be

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Speaker 1: a structure. They're definitely going to dissolve into the larger

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Speaker 1: sort of bathtub of the galaxy. There are sometimes substructures

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Speaker 1: to the galaxy, but those tend to be like little

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Speaker 1: dwarf galaxies that orbit the Milky Way and that have

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Speaker 1: their own gravitational hold on themselves that haven't gotten pulled

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Speaker 1: apart by the Milky Way. But within the Milky Way,

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Speaker 1: there aren't really those kinds of structures.

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Speaker 2: So you would say, like after our solar system, the

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Speaker 2: next structure is a galaxy. You wouldn't maybe call the

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Speaker 2: arms of a galaxy a structure.

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Speaker 1: Well, those are density waves, right. Even the arms of

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Speaker 1: the galaxy are not physical structures. It's not like the

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Speaker 1: same stars are moving through those arms. The arms are

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Speaker 1: a wave through the stars. Like when you go to

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Speaker 1: a football game and people do the wave. That wave

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Speaker 1: itself is not a structure. It's just an arrangement of

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Speaker 1: the people as they move up and down. Galaxy arms

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Speaker 1: are the same way. They're not physical structures. They're just

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Speaker 1: density waves. So they're not actually whole themselves together, just

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Speaker 1: like waves in the ocean are not really structures that

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Speaker 1: I'm bound together.

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Speaker 2: And so our solar system, our star is not part

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Speaker 2: of a like a mini dwarf galaxy. We're just out

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Speaker 2: in the larger Milky Way galaxy.

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Speaker 1: Yep, we're just floating in the bathtub of the Milky Way,

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Speaker 1: along with hundreds of billions of other stars.

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Speaker 2: And potentially aliens that might eat us one of us. Right,

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Speaker 2: it sounds like a dangerous hot tub. Well, let's dig

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Speaker 2: into the next level of structure in the universe, and

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Speaker 2: let's see how big we can go. How far can

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Speaker 2: we add or recognize structure in the universe, and what's

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Speaker 2: going to happen to all that structure at the end

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Speaker 2: of time. So let's dig into that. But first let's

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Speaker 2: take a quick break. All right, we're asking the question

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Speaker 2: will our supercluster be torn apart? Which kind of sounds

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Speaker 2: like an oxymoron question or a contradictory question. Well, something

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Speaker 2: that's clustered together and not be clustered together.

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Speaker 1: Yeah, in the end, we're going to learn that astronomers

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Speaker 1: are arguing about how to define a supercluster, and some

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Speaker 1: definitions make the answer obvious, and some definitions make the

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Speaker 1: answer to this question very fuzzy.

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Speaker 2: But we were talking about how you know things, how

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Speaker 2: do you define structures? And it seems like sometimes, like

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Speaker 2: in a cloud or in a crowd, things might look

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Speaker 2: like they're together, but really they can fall apart at

437
00:21:26,400 --> 00:21:28,399
Speaker 2: any point, so you wouldn't call that a structure. But

438
00:21:28,560 --> 00:21:31,080
Speaker 2: like the atoms in your body or the atoms in

439
00:21:31,119 --> 00:21:33,359
Speaker 2: the building or car you're sitting on, they're held together

440
00:21:33,400 --> 00:21:37,640
Speaker 2: pretty tightly by forces, and they basically sort of ignore

441
00:21:37,760 --> 00:21:40,080
Speaker 2: other forces in favor of the forces that are holding

442
00:21:40,119 --> 00:21:42,280
Speaker 2: them together. And so maybe that's why we call them

443
00:21:42,400 --> 00:21:43,000
Speaker 2: a structure.

444
00:21:43,080 --> 00:21:45,320
Speaker 1: That's right, And it can be gravitational, or it can

445
00:21:45,359 --> 00:21:48,840
Speaker 1: be electromagnetic, or can be the strong force that forms

446
00:21:48,880 --> 00:21:51,720
Speaker 1: these structures, like the proton is a structure of the

447
00:21:51,760 --> 00:21:54,840
Speaker 1: strong force, and the atom is a structure of electromagnetism.

448
00:21:54,920 --> 00:21:58,920
Speaker 1: But at larger distances, basically anything bigger than a few meters,

449
00:21:59,200 --> 00:22:02,760
Speaker 1: it's mostly gravity that takes over because the other forces

450
00:22:02,760 --> 00:22:05,959
Speaker 1: are so powerful that they tend to neutralize themselves. Anything

451
00:22:06,000 --> 00:22:08,639
Speaker 1: that has a large positive or negative charge is going

452
00:22:08,680 --> 00:22:11,520
Speaker 1: to attract the opposite charge and end up neutralizing itself,

453
00:22:11,560 --> 00:22:15,200
Speaker 1: but over the large distances, it's gravity that forms structure

454
00:22:15,200 --> 00:22:19,480
Speaker 1: because gravity cannot be neutralized. Essentially, it's only attractive. There

455
00:22:19,480 --> 00:22:21,720
Speaker 1: are a few scenarios we can talk about with like

456
00:22:21,800 --> 00:22:25,320
Speaker 1: repulsive gravity, and dark energy might be an example of that,

457
00:22:25,359 --> 00:22:27,800
Speaker 1: but on the whole, gravity is attractive, and so it's

458
00:22:27,920 --> 00:22:30,399
Speaker 1: the force that's responsible for most of the structure we

459
00:22:30,440 --> 00:22:31,560
Speaker 1: think about in the universe.

460
00:22:31,840 --> 00:22:32,080
Speaker 5: Mmm.

461
00:22:32,400 --> 00:22:34,600
Speaker 2: Yeah, Like after about the size of a planet, there's

462
00:22:34,600 --> 00:22:37,320
Speaker 2: no other forces really at play in the universe that

463
00:22:37,400 --> 00:22:39,520
Speaker 2: we know of. Maybe there's something hitting out there. Could

464
00:22:39,600 --> 00:22:41,200
Speaker 2: dark matter be some kind of new force?

465
00:22:42,280 --> 00:22:44,440
Speaker 1: It could in dark energy is definitely in that category.

466
00:22:44,480 --> 00:22:47,600
Speaker 1: We don't know if it's a manifestation of gravity due

467
00:22:47,600 --> 00:22:50,960
Speaker 1: to the quantum energy of space or something totally else

468
00:22:51,040 --> 00:22:51,560
Speaker 1: and weird.

469
00:22:51,800 --> 00:22:54,240
Speaker 2: All right, Well, we talked about how we're part of

470
00:22:54,280 --> 00:22:57,080
Speaker 2: a solar system, and the Solar system is part of

471
00:22:57,680 --> 00:23:00,000
Speaker 2: a bigger structure called the Milky Way galaxy.

472
00:23:00,200 --> 00:23:02,720
Speaker 1: After that, so the galaxies aren't just like floating out

473
00:23:02,760 --> 00:23:06,240
Speaker 1: in space sprinkled evenly through the universe. They tend to

474
00:23:06,359 --> 00:23:08,800
Speaker 1: clump together, and they can clump together into something that

475
00:23:08,840 --> 00:23:12,280
Speaker 1: we call a galactic group or a group of galaxies

476
00:23:12,400 --> 00:23:14,440
Speaker 1: in our galaxy, the Milky Way is part of a

477
00:23:14,480 --> 00:23:17,639
Speaker 1: group we call the Local Group very cleverly, and it

478
00:23:17,680 --> 00:23:21,240
Speaker 1: has about fifty ish galaxies in it. The biggest one

479
00:23:21,400 --> 00:23:24,200
Speaker 1: is Andromeda, which is also the nearest one to us.

480
00:23:24,400 --> 00:23:27,160
Speaker 2: And so these are galaxies that are not just neros

481
00:23:27,240 --> 00:23:30,560
Speaker 2: out of convenience. We're actually sort of locked together with

482
00:23:30,720 --> 00:23:33,680
Speaker 2: them in some sort of gravitational dance. Right.

483
00:23:33,760 --> 00:23:36,639
Speaker 1: Yeah. We think that these galaxies are holding themselves together.

484
00:23:36,680 --> 00:23:40,520
Speaker 1: They're like a single gravitational object. They are orbiting the

485
00:23:40,520 --> 00:23:43,879
Speaker 1: center of mass of all of these galaxies. And people

486
00:23:43,920 --> 00:23:47,159
Speaker 1: hear a lot that the universe is expanding and everything

487
00:23:47,200 --> 00:23:49,360
Speaker 1: is getting farther and farther away. And that's true sort

488
00:23:49,359 --> 00:23:51,679
Speaker 1: of on the whole when you look at vast distances,

489
00:23:52,160 --> 00:23:55,440
Speaker 1: but nearby gravity is powerful enough to hold us together,

490
00:23:55,880 --> 00:23:59,360
Speaker 1: and that's happening also with these galaxies. That's why, for example,

491
00:23:59,560 --> 00:24:02,960
Speaker 1: we are towards the Andromeda galaxy and in a few

492
00:24:02,960 --> 00:24:06,520
Speaker 1: billion years our galaxy and Andromeda will collide and will

493
00:24:06,560 --> 00:24:09,679
Speaker 1: merge because gravity is winning the battle over the expansion

494
00:24:09,760 --> 00:24:12,560
Speaker 1: of space. So this local group, we think, is a thing.

495
00:24:12,640 --> 00:24:16,159
Speaker 1: It's a structure that gravity is powerful enough to hold together.

496
00:24:16,320 --> 00:24:18,760
Speaker 2: And now what kind of shape does this local group have?

497
00:24:19,000 --> 00:24:21,000
Speaker 2: Is it like a disk like our solar system or

498
00:24:21,080 --> 00:24:22,919
Speaker 2: the galaxy, or is it still kind of like a

499
00:24:22,960 --> 00:24:26,200
Speaker 2: fuzzy cloud of things moving in all directions.

500
00:24:26,320 --> 00:24:28,960
Speaker 1: It doesn't really have a great shape because it's sort

501
00:24:29,000 --> 00:24:32,440
Speaker 1: of weirdly distributed, like there's Andromeda, then there's the Milky Way,

502
00:24:32,560 --> 00:24:36,000
Speaker 1: there's another galaxy called the Triangular Galaxy, and the rest

503
00:24:36,040 --> 00:24:38,879
Speaker 1: of it is like a sprinkle of little tiny galaxies.

504
00:24:39,240 --> 00:24:41,800
Speaker 1: So they're not like nicely organized into a flat disc

505
00:24:42,240 --> 00:24:44,840
Speaker 1: or anything like that. It's just sort of like a blob.

506
00:24:45,160 --> 00:24:47,000
Speaker 2: Or at least not yet. Right, Like, maybe if you

507
00:24:47,080 --> 00:24:49,640
Speaker 2: fast forward a few billion years, things will even out

508
00:24:49,640 --> 00:24:51,560
Speaker 2: into a disk, because that's what things do in space,

509
00:24:51,640 --> 00:24:54,640
Speaker 2: they organize themselves into discs, right.

510
00:24:54,720 --> 00:24:56,280
Speaker 1: They do tend to do that if you give them

511
00:24:56,359 --> 00:24:59,960
Speaker 1: enough time, because they're spinning and gravity will collapse everything

512
00:25:00,119 --> 00:25:02,439
Speaker 1: down eventually, except along the plane of their spin they

513
00:25:02,440 --> 00:25:05,000
Speaker 1: can resist gravity a little bit, which is why they

514
00:25:05,080 --> 00:25:07,439
Speaker 1: end up as disks. So in sort of one direction

515
00:25:07,520 --> 00:25:09,720
Speaker 1: they can collapse, and along the other two dimensions on

516
00:25:09,760 --> 00:25:12,359
Speaker 1: that plane they end up sort of spinning around, which

517
00:25:12,359 --> 00:25:14,119
Speaker 1: is how you get a flat solar system and a

518
00:25:14,119 --> 00:25:17,920
Speaker 1: flat galaxy. Eventually, though, we think that gravity will win,

519
00:25:18,119 --> 00:25:20,080
Speaker 1: that those things will bump against each other and lose

520
00:25:20,119 --> 00:25:24,040
Speaker 1: angular momentum, or they will radiate gravitational waves and lose

521
00:25:24,080 --> 00:25:27,600
Speaker 1: that energy. And eventually we think that gravitationally bound objects

522
00:25:27,680 --> 00:25:30,840
Speaker 1: will all collapse together, first into one big galaxy and

523
00:25:30,880 --> 00:25:33,040
Speaker 1: then eventually just into one big black hole.

524
00:25:33,359 --> 00:25:33,600
Speaker 3: Yit.

525
00:25:33,880 --> 00:25:37,000
Speaker 2: But before that happens, we can see other kinds of structures, right,

526
00:25:37,040 --> 00:25:40,119
Speaker 2: bigger structures, So like a group of galaxies can be

527
00:25:40,160 --> 00:25:42,840
Speaker 2: part of a larger kind of thing.

528
00:25:43,119 --> 00:25:45,080
Speaker 1: Yeah, so we call this either a group or a

529
00:25:45,119 --> 00:25:48,240
Speaker 1: cluster of galaxies. And depending on the size, like if

530
00:25:48,280 --> 00:25:50,919
Speaker 1: there aren't that many galaxies in it, like in hours,

531
00:25:50,920 --> 00:25:53,560
Speaker 1: we call it a group. If there are more galaxies

532
00:25:53,560 --> 00:25:56,040
Speaker 1: in it, you can call it a cluster. And so nearby,

533
00:25:56,160 --> 00:25:59,159
Speaker 1: for example, is the Virgo cluster. It has more than

534
00:25:59,240 --> 00:26:01,919
Speaker 1: a thousand galaxies that are like the Milky Way, so

535
00:26:01,960 --> 00:26:05,119
Speaker 1: it's much much bigger than the local group, and we

536
00:26:05,119 --> 00:26:07,520
Speaker 1: think that is also like an object that has structure,

537
00:26:07,720 --> 00:26:09,800
Speaker 1: we think it's going to hold itself together, that there's

538
00:26:09,920 --> 00:26:12,119
Speaker 1: enough gravity to keep itself together.

539
00:26:12,359 --> 00:26:15,400
Speaker 2: Yeah, isn't it pretty amazing to think even at these numbers,

540
00:26:15,440 --> 00:26:17,320
Speaker 2: like a thousand. A thousand doesn't sound like a lot,

541
00:26:17,480 --> 00:26:21,160
Speaker 2: But if you imagine a thousand galaxies like the Milky Way,

542
00:26:21,400 --> 00:26:23,880
Speaker 2: that is sort of mind blowing. Right, Like, we think

543
00:26:23,920 --> 00:26:27,040
Speaker 2: our galaxy is pretty huge and we'll probably never get

544
00:26:27,080 --> 00:26:29,520
Speaker 2: to the other side of it, and has billions of stars.

545
00:26:29,960 --> 00:26:32,119
Speaker 2: Now imagine there are thousands of these things out there

546
00:26:32,119 --> 00:26:32,560
Speaker 2: in space.

547
00:26:32,680 --> 00:26:34,800
Speaker 1: And the thing that blows my mind is the planets. Right,

548
00:26:34,880 --> 00:26:37,199
Speaker 1: even in our galaxy, we know there are hundreds of

549
00:26:37,280 --> 00:26:40,840
Speaker 1: billions of stars, and a significant fraction of those have

550
00:26:41,000 --> 00:26:44,000
Speaker 1: Earth like planets. You know, planets about the same size

551
00:26:44,040 --> 00:26:47,000
Speaker 1: with about the same surface temperature. We don't really know

552
00:26:47,119 --> 00:26:49,639
Speaker 1: that much more about them, but like, that's a lot

553
00:26:49,720 --> 00:26:53,200
Speaker 1: of Earth like planets. We're talking about tens of billions

554
00:26:53,280 --> 00:26:56,040
Speaker 1: just in our galaxy, and now multiply that by a

555
00:26:56,119 --> 00:27:00,240
Speaker 1: thousand for all the galaxies in the Virgo clusters hard

556
00:27:00,240 --> 00:27:02,640
Speaker 1: to keep track of, like all the places aliens could

557
00:27:02,640 --> 00:27:04,280
Speaker 1: be sharpening their barbecue tools.

558
00:27:04,560 --> 00:27:08,000
Speaker 2: Yeah, so let's not think about that. Yeah, I agree with.

559
00:27:08,000 --> 00:27:13,080
Speaker 1: You, But the Virgo cluster is like the biggest thing around.

560
00:27:13,119 --> 00:27:16,320
Speaker 1: There are other little galaxy groups nearby, Like there's the

561
00:27:16,440 --> 00:27:19,520
Speaker 1: M eighty one group, and the Sculptor group other little

562
00:27:19,600 --> 00:27:22,120
Speaker 1: groups of galaxies that are sort of in this sort

563
00:27:22,160 --> 00:27:24,639
Speaker 1: of the same size as our group. But the Virgo

564
00:27:24,680 --> 00:27:28,000
Speaker 1: cluster is like the big Papa and Mama galaxy cluster nearby.

565
00:27:28,040 --> 00:27:30,760
Speaker 1: It's like the most massive thing in the nearby universe.

566
00:27:31,000 --> 00:27:33,920
Speaker 2: Well, it's interesting with gravity, I feel, because gravity doesn't

567
00:27:33,920 --> 00:27:37,240
Speaker 2: have a limit, right, Like there's no distance limit for gravity,

568
00:27:37,480 --> 00:27:40,120
Speaker 2: Like this Virgo cluster is super dup or duper far

569
00:27:40,160 --> 00:27:43,359
Speaker 2: away from us. But technically speaking, like the atoms in

570
00:27:43,400 --> 00:27:46,040
Speaker 2: my body and in your body and everybody's bodies is

571
00:27:46,080 --> 00:27:50,680
Speaker 2: being tugged pulled by the gravity of that cluster super

572
00:27:50,720 --> 00:27:51,120
Speaker 2: far away.

573
00:27:51,200 --> 00:27:54,479
Speaker 1: That's right, Everything in the universe technically is pulling on

574
00:27:54,520 --> 00:27:57,280
Speaker 1: you gravitationally. Gravity does have this weakness though, which is

575
00:27:57,560 --> 00:28:01,520
Speaker 1: that its power drops as the dist is squared. So

576
00:28:01,560 --> 00:28:04,360
Speaker 1: if you're twice as far away from something, it's gravity

577
00:28:04,400 --> 00:28:06,880
Speaker 1: goes down by a factor of four. If you're ten

578
00:28:06,960 --> 00:28:09,560
Speaker 1: times further away, then the gravity goes down by a

579
00:28:09,600 --> 00:28:11,520
Speaker 1: factor of one hundred. And this gets to be a

580
00:28:11,600 --> 00:28:15,880
Speaker 1: very powerful obstacle to gravity as distances grow large, and

581
00:28:15,960 --> 00:28:18,360
Speaker 1: so the Virgo cluster, even though it's the most massive

582
00:28:18,359 --> 00:28:21,360
Speaker 1: thing in the nearby universe. It's like fifty or sixty

583
00:28:21,640 --> 00:28:26,760
Speaker 1: million light years away. That's a big distance to square, right,

584
00:28:27,080 --> 00:28:29,840
Speaker 1: So its gravity is really tiny, which is why it's

585
00:28:29,840 --> 00:28:32,720
Speaker 1: not obvious whether our little group, the local group, and

586
00:28:32,800 --> 00:28:35,439
Speaker 1: the Virgo cluster should be considered as part of some

587
00:28:35,600 --> 00:28:36,440
Speaker 1: larger object.

588
00:28:36,680 --> 00:28:36,840
Speaker 3: Right.

589
00:28:36,880 --> 00:28:39,680
Speaker 2: It gets attenuated a lot, it weakened a lot by distance,

590
00:28:39,720 --> 00:28:42,000
Speaker 2: but it's still there, right, Like I feel like like

591
00:28:42,040 --> 00:28:46,040
Speaker 2: I'm sensing I have this feeling of like a small

592
00:28:46,200 --> 00:28:49,240
Speaker 2: tendril of force that pulls me from the atoms in

593
00:28:49,320 --> 00:28:52,800
Speaker 2: my body to the Virgo cluster, right, And it also

594
00:28:52,880 --> 00:28:54,920
Speaker 2: kind of depends like what if the Virgo cluster was

595
00:28:55,560 --> 00:28:59,960
Speaker 2: super duper massive, right, we would eventually feel their gravity.

596
00:29:00,120 --> 00:29:02,520
Speaker 1: Yeah, that's true, and we do feel it's gravity. You're

597
00:29:02,520 --> 00:29:05,120
Speaker 1: absolutely right. I feel like you're just sort of preparing

598
00:29:05,160 --> 00:29:07,040
Speaker 1: an argument for when the aliens come and you're like,

599
00:29:07,080 --> 00:29:09,240
Speaker 1: hey man, we're all part of the same thing, and

600
00:29:09,320 --> 00:29:11,400
Speaker 1: we can feel your gravity, and we do, and we

601
00:29:11,480 --> 00:29:14,360
Speaker 1: can feel that gravity. And there's another way in which

602
00:29:14,400 --> 00:29:17,040
Speaker 1: we are connected to those objects. Right now, we're just

603
00:29:17,120 --> 00:29:20,480
Speaker 1: thinking mostly about the stars, the things that shine brightly,

604
00:29:20,600 --> 00:29:23,600
Speaker 1: but there are these filaments that connect us to the

605
00:29:23,680 --> 00:29:27,640
Speaker 1: other galaxies. Like between US and ANDRAMA is not empty space.

606
00:29:27,720 --> 00:29:32,160
Speaker 1: There's this filament, this string of both matter like hydrogen atoms,

607
00:29:32,160 --> 00:29:35,520
Speaker 1: et cetera, and also dark matter. So it's not like

608
00:29:35,600 --> 00:29:38,640
Speaker 1: a bunch of dots out in space. These galaxies they're

609
00:29:38,680 --> 00:29:42,080
Speaker 1: connected to each other. It's part of some huge cosmic

610
00:29:42,200 --> 00:29:45,040
Speaker 1: web where the other parts are more invisible because they're

611
00:29:45,080 --> 00:29:45,720
Speaker 1: not glowing.

612
00:29:46,400 --> 00:29:48,640
Speaker 2: Yeah, it's sort of like a spider's web right the universe.

613
00:29:48,720 --> 00:29:50,360
Speaker 2: Like if you look at a picture of the universe

614
00:29:50,520 --> 00:29:52,640
Speaker 2: and all the stars in it, the stars, even though

615
00:29:52,680 --> 00:29:55,440
Speaker 2: they're pinpoints, they sort of don't look like a random

616
00:29:55,480 --> 00:29:58,600
Speaker 2: white noise. They sort of look like a spider's web kind.

617
00:29:58,520 --> 00:30:02,640
Speaker 1: Of mm hmm. Between those dots there really is stuff.

618
00:30:03,040 --> 00:30:06,320
Speaker 1: You know, galaxies form in certain locations because that happens

619
00:30:06,360 --> 00:30:08,640
Speaker 1: to me where there was a little bit more dark matter.

620
00:30:09,120 --> 00:30:11,200
Speaker 1: So there's like a blob of dark matter there that's

621
00:30:11,240 --> 00:30:16,000
Speaker 1: gathered together enough light to start fusion going in those stars.

622
00:30:16,080 --> 00:30:18,640
Speaker 1: But between them there are these filaments of gas and

623
00:30:18,760 --> 00:30:22,240
Speaker 1: dark matter still flowing into those halos. So you could

624
00:30:22,240 --> 00:30:24,760
Speaker 1: think about it like a network of lakes with rivers

625
00:30:24,800 --> 00:30:27,800
Speaker 1: flowing into them, still filling them up, So galaxies are

626
00:30:27,840 --> 00:30:32,160
Speaker 1: still gathering dark matter and gas from these filaments. Structure

627
00:30:32,160 --> 00:30:35,840
Speaker 1: there is still sort of forming. Even though fourteen billion

628
00:30:35,920 --> 00:30:38,640
Speaker 1: years have gone by, things are still happening out there

629
00:30:38,640 --> 00:30:39,280
Speaker 1: in the universe.

630
00:30:40,080 --> 00:30:42,000
Speaker 2: I guess if there's a big cloud of something like

631
00:30:42,080 --> 00:30:44,560
Speaker 2: hydrogen out there in the middle of empty space, gravity

632
00:30:44,600 --> 00:30:47,680
Speaker 2: would be pulling it together, that cloud together into a

633
00:30:47,720 --> 00:30:50,600
Speaker 2: smaller cloud, and then our gravity would be and the

634
00:30:50,640 --> 00:30:52,840
Speaker 2: gravity of other clusters would be trying to stuck that

635
00:30:52,960 --> 00:30:55,560
Speaker 2: gas towards them. And so that's why maybe you get

636
00:30:55,600 --> 00:30:58,680
Speaker 2: these tendrils, these sort of like tentacles of gas out

637
00:30:58,680 --> 00:31:00,880
Speaker 2: there in space because they're being straight out and sucked

638
00:31:00,880 --> 00:31:03,000
Speaker 2: and do the different galaxies.

639
00:31:02,520 --> 00:31:05,480
Speaker 1: Exactly, And mostly it's the dark matter doing that. Remember,

640
00:31:05,520 --> 00:31:09,040
Speaker 1: we only see the visible matter, but that's twenty percent

641
00:31:09,240 --> 00:31:11,680
Speaker 1: of the matter that's out there, most of the gravity

642
00:31:11,680 --> 00:31:14,520
Speaker 1: in the universe. Most of those tendrils you feel from

643
00:31:14,520 --> 00:31:17,440
Speaker 1: the other cluster are actually from the dark matter in

644
00:31:17,480 --> 00:31:19,960
Speaker 1: that cluster, because that's most of the matter, and so

645
00:31:20,120 --> 00:31:22,680
Speaker 1: most of the gravity in the universe. Like, the reason

646
00:31:22,680 --> 00:31:25,000
Speaker 1: we have a galaxy here and not somewhere else is

647
00:31:25,040 --> 00:31:28,040
Speaker 1: because there was dark matter to form this structure. It

648
00:31:28,080 --> 00:31:30,920
Speaker 1: created this like gravitational well, the sort of lake to

649
00:31:31,040 --> 00:31:33,720
Speaker 1: pull all the other rivers of matter into it.

650
00:31:34,000 --> 00:31:37,680
Speaker 2: Cool. Well, after a cluster of galaxies, what's next?

651
00:31:37,920 --> 00:31:40,560
Speaker 1: So what's next is a little bit controversial, and in

652
00:31:40,600 --> 00:31:42,200
Speaker 1: the last ten years or so there's been a lot

653
00:31:42,240 --> 00:31:44,960
Speaker 1: of arguments about it. But there's a group of astronomers

654
00:31:45,000 --> 00:31:47,520
Speaker 1: out there that say that all these clusters, in these

655
00:31:47,560 --> 00:31:51,160
Speaker 1: little groups can be gathered together into something bigger called

656
00:31:51,200 --> 00:31:54,960
Speaker 1: a supercluster. The supercluster would take like the Virgo cluster

657
00:31:55,440 --> 00:31:57,840
Speaker 1: and our little group, and a bunch of other things,

658
00:31:57,880 --> 00:32:01,000
Speaker 1: including like the Great Attractor and them a cluster, and

659
00:32:01,040 --> 00:32:04,960
Speaker 1: the Centauris cluster and many others, into some huge object

660
00:32:05,000 --> 00:32:07,600
Speaker 1: that has like one hundred thousand galaxies in it.

661
00:32:07,760 --> 00:32:11,920
Speaker 2: Right, And this supercluster is called the Lenni Kiak supercluster. Right.

662
00:32:12,080 --> 00:32:15,000
Speaker 1: Yeah, it's a Hawaiian word that means immense heaven, and

663
00:32:14,960 --> 00:32:17,840
Speaker 1: it were defined in like twenty fourteen when a bunch

664
00:32:17,880 --> 00:32:20,560
Speaker 1: of astronomers looked at the velocity of all these things

665
00:32:20,560 --> 00:32:22,640
Speaker 1: and said, you know what, all these things are sort

666
00:32:22,680 --> 00:32:26,520
Speaker 1: of like falling towards themselves, and there's another blob of

667
00:32:26,560 --> 00:32:30,080
Speaker 1: stuff over there that's falling towards themselves, and so they

668
00:32:30,200 --> 00:32:32,080
Speaker 1: figure out how to sort of like draw a line

669
00:32:32,120 --> 00:32:35,160
Speaker 1: between one set of blobs and another set of blobs,

670
00:32:35,200 --> 00:32:37,680
Speaker 1: and they said, we're in this blob over here.

671
00:32:38,040 --> 00:32:41,360
Speaker 2: M I see. But can you make the mathematical calculation,

672
00:32:41,520 --> 00:32:45,080
Speaker 2: like if you compute the gravity that we're feeling between

673
00:32:45,120 --> 00:32:48,520
Speaker 2: these clusters, and does it really work out that you

674
00:32:48,640 --> 00:32:53,280
Speaker 2: can group these superclusters as one or is it more

675
00:32:53,320 --> 00:32:55,800
Speaker 2: like an illusion like a wisp of cloud or a

676
00:32:55,880 --> 00:32:57,040
Speaker 2: crowd of people in a park.

677
00:32:57,240 --> 00:32:59,680
Speaker 1: Yeah, that's exactly the question, and that's really what we're

678
00:32:59,720 --> 00:33:03,680
Speaker 1: in entering today is what is the future of this supercluster?

679
00:33:03,880 --> 00:33:06,240
Speaker 1: Is it going to hold itself together or is it

680
00:33:06,240 --> 00:33:08,720
Speaker 1: going to get torn apart? Because we've been talking about

681
00:33:08,760 --> 00:33:12,120
Speaker 1: gravity so far, but there's another force at play here,

682
00:33:12,200 --> 00:33:15,200
Speaker 1: and that's dark energy. If it was only gravity, then

683
00:33:15,240 --> 00:33:18,480
Speaker 1: this thing would collapse. Landi Ko would definitely fall into

684
00:33:18,600 --> 00:33:21,640
Speaker 1: one big object and maybe form one super galaxy and

685
00:33:21,680 --> 00:33:25,280
Speaker 1: one super black hole. There is enough gravity if the

686
00:33:25,360 --> 00:33:28,600
Speaker 1: universe wasn't expanding to pull this thing together, like it's

687
00:33:28,640 --> 00:33:32,480
Speaker 1: already right now falling inwards. Everything in the Lanti Kia

688
00:33:32,560 --> 00:33:36,840
Speaker 1: supercluster has an overall in falling velocity. But there's another

689
00:33:36,840 --> 00:33:39,160
Speaker 1: player on this stage, right, which is the expansion of

690
00:33:39,240 --> 00:33:42,360
Speaker 1: the universe, and this has a very different behavior as

691
00:33:42,400 --> 00:33:45,600
Speaker 1: distances grow large, like gravity gets weaker and weaker as

692
00:33:45,640 --> 00:33:49,160
Speaker 1: distances grow large, but dark energy, this accelerating expansion of

693
00:33:49,160 --> 00:33:52,760
Speaker 1: the universe, gets more powerful as distances grow large. So

694
00:33:52,800 --> 00:33:55,480
Speaker 1: at some point it takes over. There's like a crossover

695
00:33:55,560 --> 00:33:57,560
Speaker 1: point where dark energy starts to win.

696
00:33:57,880 --> 00:33:59,880
Speaker 2: Well, let's stick into that to gives that is the

697
00:34:00,240 --> 00:34:02,360
Speaker 2: question of the episode. Now we are in the Lenni

698
00:34:02,400 --> 00:34:05,600
Speaker 2: Kia supercluster, and so the question is is something tearing

699
00:34:05,720 --> 00:34:09,120
Speaker 2: it apart. It's the biggest structure in the universe, and

700
00:34:09,200 --> 00:34:12,880
Speaker 2: so Danny, you're saying that maybe dark energy is tearing

701
00:34:12,920 --> 00:34:15,800
Speaker 2: it apart, or maybe at least fraying it at the edges.

702
00:34:16,040 --> 00:34:18,600
Speaker 1: Yeah, dark energy is definitely working to tear it apart.

703
00:34:18,719 --> 00:34:20,839
Speaker 1: And listeners right in all the time and ask about

704
00:34:20,920 --> 00:34:24,040
Speaker 1: dark energy and have this idea sometimes that dark energy

705
00:34:24,080 --> 00:34:26,880
Speaker 1: is something happening at the edges of the universe, that

706
00:34:26,920 --> 00:34:29,520
Speaker 1: there's something pulling on us from the outside, or that

707
00:34:29,560 --> 00:34:33,239
Speaker 1: maybe the expansion is only happening out there between galaxies,

708
00:34:33,280 --> 00:34:36,160
Speaker 1: but the expansion is happening everywhere. Every chunk of space

709
00:34:36,320 --> 00:34:39,560
Speaker 1: is expanding. Like the Hubble constant is a measure of

710
00:34:39,600 --> 00:34:43,840
Speaker 1: how fast things are expanding, and it's like seventy kilometers

711
00:34:43,880 --> 00:34:47,040
Speaker 1: per second per megaparsek, which is sort of a hard

712
00:34:47,040 --> 00:34:48,680
Speaker 1: thing to get your mind around, but really it just

713
00:34:48,760 --> 00:34:51,720
Speaker 1: means that, like every megaparsec, which is like three light years,

714
00:34:52,160 --> 00:34:56,280
Speaker 1: grows by about seventy kilometers every second, and that happens

715
00:34:56,280 --> 00:34:59,239
Speaker 1: everywhere in space. If you have a smaller distance, like

716
00:34:59,239 --> 00:35:01,520
Speaker 1: the distance between Earth in the Sun, which is only

717
00:35:01,600 --> 00:35:04,640
Speaker 1: a few tens of millions of miles, it would grow

718
00:35:04,760 --> 00:35:08,520
Speaker 1: by a much smaller amount than seventy kilometers every second.

719
00:35:08,920 --> 00:35:11,040
Speaker 1: So that expansion is happening everywhere, but it's sort of

720
00:35:11,080 --> 00:35:14,800
Speaker 1: faint and weak. It's not very strong over short distances,

721
00:35:14,840 --> 00:35:17,600
Speaker 1: and gravity is strong enough to hold us together against

722
00:35:17,600 --> 00:35:21,080
Speaker 1: this like very weak breeze of dark energy. But then

723
00:35:21,120 --> 00:35:24,360
Speaker 1: at large distances, when gravity is weak, dark energy is

724
00:35:24,400 --> 00:35:26,920
Speaker 1: more powerful. It sort of adds up as you get

725
00:35:26,920 --> 00:35:30,200
Speaker 1: to these bigger distances, and so for the supercluster, it

726
00:35:30,320 --> 00:35:33,839
Speaker 1: really is an interesting question of whether that's the crossover point.

727
00:35:34,200 --> 00:35:37,319
Speaker 2: Yeah, it's interesting to think about. Like even here in

728
00:35:37,360 --> 00:35:40,120
Speaker 2: the room where I'm at, and the room where you are,

729
00:35:40,200 --> 00:35:42,520
Speaker 2: and where our listeners are. If you just stare at

730
00:35:42,560 --> 00:35:45,560
Speaker 2: your hand, like the space that your hand is occupying

731
00:35:45,760 --> 00:35:49,839
Speaker 2: is expanding, it's getting trying to like pull your hand

732
00:35:49,880 --> 00:35:51,680
Speaker 2: apart in a way, except that your hand is being

733
00:35:51,719 --> 00:35:54,360
Speaker 2: held together by the bonds of the atoms in it.

734
00:35:54,400 --> 00:35:56,160
Speaker 2: But if it wasn't your hand, which is kind of

735
00:35:56,160 --> 00:35:57,440
Speaker 2: dissipate eventually.

736
00:35:57,120 --> 00:35:59,759
Speaker 1: Right, Yeah, exactly, if there wasn't gravity and there weren't

737
00:35:59,760 --> 00:36:03,080
Speaker 1: those forces, than dark energy would pull your hand apart,

738
00:36:03,160 --> 00:36:05,200
Speaker 1: and it would pull the Earth from the Sun. So

739
00:36:05,239 --> 00:36:07,520
Speaker 1: there's a bunch of really interesting things all happening at

740
00:36:07,520 --> 00:36:11,520
Speaker 1: the same time. Like gravity needs time to form structure.

741
00:36:12,000 --> 00:36:14,560
Speaker 1: You start from like a fuzzy universe, and it gradually

742
00:36:14,600 --> 00:36:18,080
Speaker 1: pulls things together, and so as time goes on, gravity

743
00:36:18,120 --> 00:36:21,400
Speaker 1: makes bigger and bigger and bigger structures. So one reason

744
00:36:21,440 --> 00:36:24,960
Speaker 1: we don't have bigger structures than superclusters, or even if

745
00:36:25,000 --> 00:36:28,479
Speaker 1: superclusters counter structure is just time. Like without dark energy,

746
00:36:28,480 --> 00:36:31,160
Speaker 1: if you ran the universe forward, it would form larger

747
00:36:31,200 --> 00:36:34,160
Speaker 1: and larger and larger structures. But dark energy turned on

748
00:36:34,239 --> 00:36:37,080
Speaker 1: a few billion years ago and it started accelerating the

749
00:36:37,120 --> 00:36:39,920
Speaker 1: expansion of the universe. So gravity is sort of running

750
00:36:39,960 --> 00:36:43,000
Speaker 1: out of time, which means something kind of fascinating. It

751
00:36:43,040 --> 00:36:45,520
Speaker 1: means that we are living maybe at the moment of

752
00:36:45,560 --> 00:36:48,040
Speaker 1: the largest structures in the universe.

753
00:36:48,360 --> 00:36:50,360
Speaker 2: Well, I think that's kind of the point of discussion,

754
00:36:50,440 --> 00:36:53,600
Speaker 2: is like, is dark energy eventually going to tear our

755
00:36:53,680 --> 00:36:56,719
Speaker 2: supercluster apart? Or is maybe that expansion not strong enough

756
00:36:56,719 --> 00:36:59,520
Speaker 2: to really tear apart and keep things the way they

757
00:36:59,520 --> 00:37:02,640
Speaker 2: are forever, Right, that's kind of the question we're asking today.

758
00:37:02,719 --> 00:37:05,839
Speaker 1: Yeah, that's right. But whether or not our supercluster survives,

759
00:37:05,880 --> 00:37:09,440
Speaker 1: there will never be anything bigger in the universe because

760
00:37:09,520 --> 00:37:12,759
Speaker 1: dark energy is getting more and more powerful, and so

761
00:37:12,880 --> 00:37:16,359
Speaker 1: gravity will never have time to make anything bigger. Like

762
00:37:16,440 --> 00:37:19,480
Speaker 1: if a structure hasn't formed by now in the universe,

763
00:37:19,760 --> 00:37:23,440
Speaker 1: it will not because dark energy is just growing in power.

764
00:37:23,600 --> 00:37:27,399
Speaker 1: So whether or not our supercluster survives, nothing bigger than

765
00:37:27,440 --> 00:37:29,960
Speaker 1: anything that's been made already will ever be made.

766
00:37:30,080 --> 00:37:32,919
Speaker 2: Well, let's dig into that and what it might mean

767
00:37:33,000 --> 00:37:36,880
Speaker 2: for our local structure or superstructure of galaxies. Does that

768
00:37:36,920 --> 00:37:40,040
Speaker 2: reduce our chances of getting eaten by aliens? We'll see. First,

769
00:37:40,120 --> 00:37:55,360
Speaker 2: let's take another quick break all right, we're talking about

770
00:37:55,600 --> 00:37:58,840
Speaker 2: getting eaten by aliens. Now, Daniel, are you sort of prepared?

771
00:37:59,040 --> 00:38:00,759
Speaker 2: It sounds like you look forward to it. Now are

772
00:38:00,800 --> 00:38:02,839
Speaker 2: you preparing yourself? Are you staying in shape? Or are

773
00:38:02,840 --> 00:38:07,160
Speaker 2: you trying to fan yourself like like your goose so

774
00:38:07,160 --> 00:38:09,800
Speaker 2: that you're tastier to the aliens? You know, tag on

775
00:38:09,840 --> 00:38:10,480
Speaker 2: those calories.

776
00:38:11,360 --> 00:38:13,520
Speaker 1: I just don't even know, Like what do aliens like?

777
00:38:13,560 --> 00:38:16,880
Speaker 1: How am I supposed to anticipate what they're gonna find? Yummy? Like?

778
00:38:17,280 --> 00:38:19,440
Speaker 1: So I'm just living my life, you know, and hoping

779
00:38:19,800 --> 00:38:20,839
Speaker 1: and hoping that they.

780
00:38:20,760 --> 00:38:26,279
Speaker 2: Put I'm hoping they pick you two over me.

781
00:38:26,680 --> 00:38:28,640
Speaker 1: Hey, something we can agree on. Awesome.

782
00:38:28,840 --> 00:38:31,879
Speaker 2: Well, we're talking about whether we're actually talking about whether

783
00:38:32,200 --> 00:38:35,640
Speaker 2: our supercluster, which is called lanny Kia, which is a

784
00:38:35,719 --> 00:38:39,120
Speaker 2: cluster of galaxy clusters, will one day be torn apart

785
00:38:39,440 --> 00:38:42,839
Speaker 2: because of dark energy. Now, dark energy is expanding all

786
00:38:42,960 --> 00:38:46,280
Speaker 2: space as far as we know, and the question is

787
00:38:46,280 --> 00:38:49,399
Speaker 2: is it expanding space faster than lanny Kiya can hold

788
00:38:49,440 --> 00:38:52,000
Speaker 2: itself together? And it sounds like you have the answer

789
00:38:52,040 --> 00:38:52,200
Speaker 2: to that.

790
00:38:52,480 --> 00:38:52,799
Speaker 3: I do.

791
00:38:52,960 --> 00:38:57,200
Speaker 1: Yeah. So originally they defined a supercluster to be this

792
00:38:57,400 --> 00:39:00,120
Speaker 1: object because everything was sort of falling in towards it.

793
00:39:00,400 --> 00:39:03,480
Speaker 1: That like delineated a blob of stuff that was moving

794
00:39:03,520 --> 00:39:05,879
Speaker 1: towards itself, and the next supercluster is a blob that's

795
00:39:05,880 --> 00:39:09,080
Speaker 1: moving towards itself. But then astronomers thought, hm, that's not

796
00:39:09,160 --> 00:39:12,240
Speaker 1: really enough. Like what we want is something that's gonna survive.

797
00:39:12,480 --> 00:39:14,680
Speaker 1: We wanted to find a supercluster to be something that

798
00:39:14,880 --> 00:39:18,200
Speaker 1: is going to manage to hold itself together against dark energy.

799
00:39:18,280 --> 00:39:20,720
Speaker 1: So they did a bunch of calculations and it looks

800
00:39:20,840 --> 00:39:23,680
Speaker 1: like it's probably not gonna make it. It looks like

801
00:39:23,760 --> 00:39:27,319
Speaker 1: the supercluster is very loosely organized. It's just more like

802
00:39:27,360 --> 00:39:30,200
Speaker 1: a cloud or like a crowd. You know, it happens

803
00:39:30,200 --> 00:39:33,400
Speaker 1: to be nearby, but it's not really like in equilibrium.

804
00:39:33,480 --> 00:39:35,239
Speaker 1: You know, like the Earth and the Sun had a

805
00:39:35,280 --> 00:39:37,520
Speaker 1: lot of time to sort of get in balance and

806
00:39:37,600 --> 00:39:39,680
Speaker 1: find a place where they're happy together, and the Earth

807
00:39:39,680 --> 00:39:42,960
Speaker 1: can orbit forever and be here. But the supercluster, like

808
00:39:43,000 --> 00:39:45,280
Speaker 1: we said earlier, hasn't really had a lot of time

809
00:39:45,360 --> 00:39:48,840
Speaker 1: to gather together and to form something solid. It's just

810
00:39:48,880 --> 00:39:51,280
Speaker 1: sort of like a big blob of stuff that happened

811
00:39:51,280 --> 00:39:53,600
Speaker 1: to be near each other and are starting to fall

812
00:39:53,640 --> 00:39:56,840
Speaker 1: in a little bit but dark energy is powerful enough

813
00:39:57,040 --> 00:39:59,000
Speaker 1: that they're pretty sure it's going to tear it apart.

814
00:39:59,239 --> 00:40:00,880
Speaker 2: Now you mentioned one one of the reasons is that

815
00:40:00,960 --> 00:40:04,680
Speaker 2: dark energy is getting stronger. Now, is it getting stronger

816
00:40:05,000 --> 00:40:07,719
Speaker 2: at the local level or is it just or you're

817
00:40:07,719 --> 00:40:10,560
Speaker 2: saying it's getting stronger because the universe is getting bigger

818
00:40:10,600 --> 00:40:13,040
Speaker 2: and so therefore there's more dark energy. Is it getting

819
00:40:13,040 --> 00:40:15,600
Speaker 2: stronger measureably like inside of my hand, Is this dark

820
00:40:15,719 --> 00:40:17,440
Speaker 2: energy that I would feel over the course of my

821
00:40:17,480 --> 00:40:20,680
Speaker 2: life getting stronger or is it going to be constant?

822
00:40:21,000 --> 00:40:24,040
Speaker 1: Dark energy is everywhere at the same level, so it's

823
00:40:24,080 --> 00:40:28,640
Speaker 1: a constant in space here and there and in other galaxies.

824
00:40:29,000 --> 00:40:32,760
Speaker 1: Every chunk of space has the same amount of dark energy.

825
00:40:33,160 --> 00:40:36,959
Speaker 1: So when the universe expands, it's making more space, which

826
00:40:37,040 --> 00:40:40,799
Speaker 1: means more dark energy doesn't get diluted. It's a constant

827
00:40:40,920 --> 00:40:44,920
Speaker 1: in space. That's not true for other stuff like matter

828
00:40:45,040 --> 00:40:49,040
Speaker 1: or radiation. As the universe expands, matter gets more dilute

829
00:40:49,120 --> 00:40:52,640
Speaker 1: because more space doesn't mean more matter. So as time

830
00:40:52,719 --> 00:40:55,640
Speaker 1: goes on, the expansion of the universe means dark energy

831
00:40:55,760 --> 00:40:59,319
Speaker 1: is constant, But then it's an increasing fraction of the

832
00:40:59,440 --> 00:41:02,680
Speaker 1: energy of the universe because it doesn't get diluted, and

833
00:41:02,719 --> 00:41:06,280
Speaker 1: other stuff does. And when dark energy is an increasing fraction,

834
00:41:06,400 --> 00:41:10,320
Speaker 1: that triggers more expansion, which only tells the balance further

835
00:41:10,520 --> 00:41:14,120
Speaker 1: towards dark energy. So it's like a runaway effect. Once

836
00:41:14,200 --> 00:41:17,440
Speaker 1: dark energy starts to win, which happened about six billion

837
00:41:17,560 --> 00:41:20,600
Speaker 1: years ago, it will zoom ahead and be impossible to

838
00:41:20,640 --> 00:41:23,600
Speaker 1: catch up to. But about seeing it change, we live

839
00:41:23,760 --> 00:41:26,560
Speaker 1: such short lives that we can't really notice it changing

840
00:41:26,680 --> 00:41:29,799
Speaker 1: on our time scales, but we can look back into

841
00:41:29,840 --> 00:41:32,680
Speaker 1: the past by looking out into deep space and seeing

842
00:41:32,719 --> 00:41:35,120
Speaker 1: how things used to be. And of course there's a

843
00:41:35,200 --> 00:41:38,759
Speaker 1: huge asterisk to all of this because we don't really

844
00:41:38,840 --> 00:41:41,600
Speaker 1: understand dark energy and what's going on and what's making

845
00:41:41,600 --> 00:41:44,320
Speaker 1: this happen, and so the rules could be very different

846
00:41:44,320 --> 00:41:47,239
Speaker 1: from this very simple model that honestly we're pretty sure

847
00:41:47,400 --> 00:41:47,840
Speaker 1: is wrong.

848
00:41:48,160 --> 00:41:50,080
Speaker 2: Right, Well, I guess what I mean is that, you know,

849
00:41:50,160 --> 00:41:52,680
Speaker 2: we've always talked about dark energy as being kind of

850
00:41:52,719 --> 00:41:56,400
Speaker 2: the force that's expanding the Universe's expanding space, and I

851
00:41:56,440 --> 00:41:58,640
Speaker 2: always think of it as sort of like the foot

852
00:41:58,719 --> 00:42:01,920
Speaker 2: in the accelerator. Like when I'm driving, I press the

853
00:42:01,960 --> 00:42:05,000
Speaker 2: accelerator and I usually leave it at a certain level

854
00:42:05,160 --> 00:42:07,840
Speaker 2: to keep going at a certain speed, and if I

855
00:42:07,840 --> 00:42:10,360
Speaker 2: want to accelerate go faster, I press it harder, and

856
00:42:10,400 --> 00:42:12,239
Speaker 2: if I want to go slower, I let go of

857
00:42:12,280 --> 00:42:14,919
Speaker 2: the pedal. Now, it sort of seems from what we've

858
00:42:14,920 --> 00:42:18,400
Speaker 2: talked about before that is that, you know, the pedal

859
00:42:18,440 --> 00:42:21,800
Speaker 2: of dark energy is sort of pretty constant. And for example,

860
00:42:21,840 --> 00:42:23,960
Speaker 2: our Solar system is never going to be torn apart

861
00:42:24,040 --> 00:42:27,160
Speaker 2: by dark energy because the gravitational bonds between us and

862
00:42:27,200 --> 00:42:29,400
Speaker 2: the Sun is strong enough that even if the space

863
00:42:29,480 --> 00:42:32,080
Speaker 2: between us gets bigger and bigger and bigger, we're always

864
00:42:32,120 --> 00:42:33,479
Speaker 2: going to hang on to the Sun.

865
00:42:33,800 --> 00:42:37,000
Speaker 1: Dark energy is expanding the space in our Solar system,

866
00:42:37,080 --> 00:42:39,800
Speaker 1: but it doesn't have much effect over those short distances.

867
00:42:39,840 --> 00:42:43,200
Speaker 1: And short distances is when gravity is the most powerful.

868
00:42:43,560 --> 00:42:46,279
Speaker 1: So gravity is always going to be powerful enough to

869
00:42:46,400 --> 00:42:49,480
Speaker 1: hold the Solar system together if dark energy is a

870
00:42:49,600 --> 00:42:53,319
Speaker 1: constant in space. Remember, a constant in space can still

871
00:42:53,360 --> 00:42:57,560
Speaker 1: be an increasing fraction of the universe's energy budget, which

872
00:42:57,640 --> 00:43:01,680
Speaker 1: leads to accelerating expansion even if the dark energy in

873
00:43:01,760 --> 00:43:04,840
Speaker 1: any given chunk of space isn't changing. Except for the

874
00:43:04,880 --> 00:43:07,880
Speaker 1: scenario of the Big Rip, where dark energy gets more

875
00:43:07,960 --> 00:43:10,600
Speaker 1: powerful and even tears our solar system apart and even

876
00:43:10,600 --> 00:43:13,279
Speaker 1: our atoms. But you're right, in our current projection of

877
00:43:13,360 --> 00:43:16,120
Speaker 1: dark energy, it will not tear apart our solar system.

878
00:43:16,200 --> 00:43:19,919
Speaker 2: Right, and so it's because it's not being accelerated enough.

879
00:43:20,000 --> 00:43:23,040
Speaker 2: Now at the level of a galaxy, do we currently

880
00:43:23,040 --> 00:43:24,920
Speaker 2: think that our galaxy is going to be torn apart

881
00:43:25,320 --> 00:43:25,520
Speaker 2: or not?

882
00:43:25,760 --> 00:43:28,279
Speaker 1: We think our galaxy is going to survive, and we

883
00:43:28,320 --> 00:43:31,760
Speaker 1: think our group is going to survive. So everything below

884
00:43:31,840 --> 00:43:35,200
Speaker 1: a supercluster, we're pretty sure gravity is already won and

885
00:43:35,239 --> 00:43:38,240
Speaker 1: it's going to continue to win again, assuming this naive

886
00:43:38,360 --> 00:43:42,359
Speaker 1: projection of dark energy continuing at the same rate that

887
00:43:42,400 --> 00:43:44,440
Speaker 1: it's been continuing, that it's not going to ramp up

888
00:43:44,480 --> 00:43:47,200
Speaker 1: into the big rip or turn around into the big crunch.

889
00:43:47,680 --> 00:43:50,400
Speaker 1: So our solar system will survive, Our galaxy will survive,

890
00:43:50,480 --> 00:43:54,280
Speaker 1: our local group will survive, The Virgo cluster nearby will survive.

891
00:43:54,480 --> 00:43:58,399
Speaker 1: But the question is will our supercluster survive? And that's

892
00:43:58,480 --> 00:44:01,359
Speaker 1: where dark energy starts to win, and dark energy will

893
00:44:01,400 --> 00:44:05,719
Speaker 1: tear these groups of galaxies apart and basically pull apart leni.

894
00:44:05,520 --> 00:44:08,799
Speaker 2: Ka because the things that make up Lenikia, you know,

895
00:44:09,080 --> 00:44:12,799
Speaker 2: our cluster, the Virgo cluster, the Great Attractor, they are

896
00:44:13,040 --> 00:44:16,839
Speaker 2: being attracted to each other, but not more than the

897
00:44:17,040 --> 00:44:19,759
Speaker 2: expansion of the huge amount of space in between them.

898
00:44:19,800 --> 00:44:20,720
Speaker 2: That's kind of what you're saying.

899
00:44:20,840 --> 00:44:24,120
Speaker 1: Yeah, it's just too big, right. Gravity gets weak over

900
00:44:24,160 --> 00:44:27,040
Speaker 1: those huge distances. It does not have the strength to

901
00:44:27,080 --> 00:44:30,399
Speaker 1: overcome dark energy, and as the distances get bigger, dark

902
00:44:30,520 --> 00:44:33,720
Speaker 1: energy becomes harder and harder to surmount. Like, it doesn't

903
00:44:33,719 --> 00:44:36,680
Speaker 1: take that much mass and that much gravity to overcome

904
00:44:36,760 --> 00:44:39,440
Speaker 1: dark energy in our solar system. It takes more mass

905
00:44:39,440 --> 00:44:42,000
Speaker 1: to overcome the dark energy in the galaxy, and even

906
00:44:42,080 --> 00:44:44,600
Speaker 1: more to overcome the dark energy of the group. But

907
00:44:44,680 --> 00:44:47,640
Speaker 1: to overcome the dark energy of the supercluster, we need

908
00:44:47,640 --> 00:44:51,040
Speaker 1: an incredible amount of mass because of the vast distances involved.

909
00:44:51,600 --> 00:44:54,400
Speaker 2: So you're saying that lani Ka, the supercluster of galaxies,

910
00:44:54,719 --> 00:44:57,719
Speaker 2: it's really more like a visual cluster, right, It's more

911
00:44:57,760 --> 00:45:00,720
Speaker 2: of a visual structure. It looks like it's holding together.

912
00:45:00,760 --> 00:45:02,920
Speaker 2: It looks like a wisp of cloud or a crowd

913
00:45:02,960 --> 00:45:05,920
Speaker 2: of people in the park, But really there's nothing that

914
00:45:06,040 --> 00:45:09,920
Speaker 2: much holding it together, or at least proportionally to the

915
00:45:10,040 --> 00:45:11,280
Speaker 2: dark energy in the universe.

916
00:45:11,400 --> 00:45:14,520
Speaker 1: Yeah, our supercluster seems to be right about that turnover

917
00:45:14,560 --> 00:45:17,600
Speaker 1: point where things that are smaller or more massive either

918
00:45:17,640 --> 00:45:20,960
Speaker 1: one would survive, and things that are bigger definitely would not.

919
00:45:21,640 --> 00:45:23,840
Speaker 1: So sort of fascinating. It's like the biggest kind of

920
00:45:23,840 --> 00:45:26,719
Speaker 1: blog we can identify, but it's not really technically a structure.

921
00:45:26,760 --> 00:45:28,800
Speaker 1: So there were some papers a few years ago suggesting

922
00:45:29,000 --> 00:45:32,160
Speaker 1: we shouldn't be calling Lenika a supercluster because it's not

923
00:45:32,239 --> 00:45:35,319
Speaker 1: a structure, And they said, maybe we should redefine what

924
00:45:35,400 --> 00:45:40,399
Speaker 1: a structure is as something that will survive in the future, right,

925
00:45:40,520 --> 00:45:43,800
Speaker 1: things that will hold themselves together in the long term

926
00:45:44,120 --> 00:45:47,759
Speaker 1: after dark energy has played itself out. So by that definition,

927
00:45:48,000 --> 00:45:51,560
Speaker 1: the lani Kaya supercluster is not actually a structure and

928
00:45:51,560 --> 00:45:53,520
Speaker 1: we shouldn't even be calling it a supercluster.

929
00:45:53,840 --> 00:45:56,239
Speaker 2: Well, I mean, as long as you're playing with definitions,

930
00:45:56,280 --> 00:45:58,719
Speaker 2: you can get either way. I feel like, right like

931
00:45:58,760 --> 00:46:02,000
Speaker 2: you could just read a find what a super cluster means.

932
00:46:02,040 --> 00:46:04,680
Speaker 2: A supercluster could just mean like a cloud or a

933
00:46:04,719 --> 00:46:07,320
Speaker 2: crowd in a park. Right, Maybe you can just define

934
00:46:07,320 --> 00:46:11,680
Speaker 2: a supercluster as not necessarily a structure, but you can

935
00:46:11,680 --> 00:46:14,320
Speaker 2: still call it a super cluster, right because a cluster,

936
00:46:14,560 --> 00:46:16,799
Speaker 2: the word cluster just means like, hey, hanging out together.

937
00:46:16,960 --> 00:46:17,319
Speaker 2: M hmm.

938
00:46:17,400 --> 00:46:20,440
Speaker 1: I suppose you could call it a banana if you wanted. Yeah,

939
00:46:20,560 --> 00:46:22,759
Speaker 1: we want these words to have some meaning to them,

940
00:46:23,320 --> 00:46:25,520
Speaker 1: and so these papers suggest that we shouldn't, and they

941
00:46:25,560 --> 00:46:29,400
Speaker 1: actually suggest another name because there are some other superclusters

942
00:46:29,640 --> 00:46:32,640
Speaker 1: that they do think will hold themselves together. So some

943
00:46:32,719 --> 00:46:36,000
Speaker 1: superclusters are more massive or a little bit closer together,

944
00:46:36,320 --> 00:46:39,239
Speaker 1: and they think they will overcome dark energy, and they

945
00:46:39,280 --> 00:46:43,960
Speaker 1: suggest calling these things supersties clusters. Super So what it's

946
00:46:43,960 --> 00:46:47,320
Speaker 1: a word in Latin that means survivor probably not pronouncing

947
00:46:47,320 --> 00:46:50,000
Speaker 1: it correctly, but I think it's superstese clusters. It's the

948
00:46:50,080 --> 00:46:55,960
Speaker 1: new name for superclusters that will survive dark energy.

949
00:46:57,239 --> 00:47:00,640
Speaker 2: It sounds like we're really rather about way for what

950
00:47:00,719 --> 00:47:02,719
Speaker 2: did you say? What did you just call them structures

951
00:47:02,719 --> 00:47:05,760
Speaker 2: like superstructures? Why do we have to go Laddin?

952
00:47:06,200 --> 00:47:08,960
Speaker 1: Well, because you know, not all superclusters are structures. They

953
00:47:08,960 --> 00:47:11,360
Speaker 1: don't hold themselves together. And you're right, we could just

954
00:47:11,360 --> 00:47:13,960
Speaker 1: put a name on things. But we like this hierarchy

955
00:47:14,000 --> 00:47:16,200
Speaker 1: of structures. We like thinking about the universe in terms

956
00:47:16,200 --> 00:47:18,640
Speaker 1: of the structures all the way down from the proton

957
00:47:18,840 --> 00:47:21,960
Speaker 1: zooming out to the biggest structures in the universe. And

958
00:47:21,960 --> 00:47:24,960
Speaker 1: we want a consistency there. We want it to mean something,

959
00:47:25,000 --> 00:47:27,040
Speaker 1: for there to be a structure you don't want just

960
00:47:27,080 --> 00:47:29,200
Speaker 1: like an arbitrary definition at every level.

961
00:47:29,320 --> 00:47:32,160
Speaker 2: Well, I feel like maybe you're only having to adjust

962
00:47:32,200 --> 00:47:35,719
Speaker 2: this definition because of dark energy, right, Like, if it

963
00:47:35,800 --> 00:47:38,480
Speaker 2: wasn't for dark energy, yeah, lenning Care would be a

964
00:47:38,480 --> 00:47:40,839
Speaker 2: structure and it would be gravitational bound and it would

965
00:47:40,920 --> 00:47:43,360
Speaker 2: last until the end of time. But you have dark energy,

966
00:47:43,440 --> 00:47:47,080
Speaker 2: which will make it fuzzy up in the future, except

967
00:47:47,120 --> 00:47:49,800
Speaker 2: that you don't know what dark energy is going to do, right,

968
00:47:49,960 --> 00:47:53,120
Speaker 2: So it seems a little bit like you're rushing ahead

969
00:47:53,160 --> 00:47:55,520
Speaker 2: to redefine everything based on something you don't know what's

970
00:47:55,560 --> 00:47:56,040
Speaker 2: going to happen.

971
00:47:56,680 --> 00:47:59,880
Speaker 1: Well, you know, astronomers love fights over names and definition

972
00:48:00,120 --> 00:48:02,520
Speaker 1: and who gets to name something, so this is one

973
00:48:02,520 --> 00:48:04,319
Speaker 1: of the hot topics these days. But you're right that

974
00:48:04,360 --> 00:48:06,840
Speaker 1: the definition of depends a little bit on what happens

975
00:48:06,840 --> 00:48:09,440
Speaker 1: in the future. In that sense, it's sort of like

976
00:48:09,520 --> 00:48:11,480
Speaker 1: the way you think about an event horizon for a

977
00:48:11,520 --> 00:48:14,800
Speaker 1: black hole, Like the event horizon isn't a physical structure,

978
00:48:14,960 --> 00:48:18,040
Speaker 1: it's just like a delineation that says anything passed here

979
00:48:18,239 --> 00:48:21,359
Speaker 1: in the infinite future will never escape. To really know that,

980
00:48:21,400 --> 00:48:24,000
Speaker 1: you have to see the infinite future. We just sort

981
00:48:24,040 --> 00:48:26,400
Speaker 1: of project it and in the same way, we like

982
00:48:26,640 --> 00:48:28,520
Speaker 1: group this stuff together and say, hey, is this going

983
00:48:28,600 --> 00:48:30,840
Speaker 1: to survive if so that we can call it a

984
00:48:30,880 --> 00:48:34,280
Speaker 1: cluster or a structure or a supercluster or a superstes

985
00:48:34,440 --> 00:48:38,319
Speaker 1: cluster or whatever the astronomers finally settle on. But the

986
00:48:38,360 --> 00:48:41,799
Speaker 1: basic story is that if dark energy continues the way

987
00:48:41,840 --> 00:48:45,560
Speaker 1: it has been, probably Lanikea will just dissolve into a

988
00:48:45,560 --> 00:48:47,200
Speaker 1: bunch of islands of mass.

989
00:48:47,360 --> 00:48:49,920
Speaker 2: It sounds more like you're saying that we shouldn't call

990
00:48:50,000 --> 00:48:51,560
Speaker 2: anything anything until the end of time.

991
00:48:52,200 --> 00:48:54,719
Speaker 1: You go, that's exactly right. We want to be totally

992
00:48:54,760 --> 00:48:56,680
Speaker 1: accurate about everything. We've got to wait to the end

993
00:48:56,719 --> 00:48:59,440
Speaker 1: of the universe. Then we'll know what was going on.

994
00:49:00,000 --> 00:49:01,799
Speaker 2: Well, let's spend the minute here because if we still

995
00:49:01,800 --> 00:49:04,319
Speaker 2: have like a few minutes left here talking about the

996
00:49:04,440 --> 00:49:06,320
Speaker 2: dark energy, right, because it seems like it all depends

997
00:49:06,320 --> 00:49:08,759
Speaker 2: on what dark energy is going to do, whether the

998
00:49:08,880 --> 00:49:11,440
Speaker 2: universe is going to press harder on the accelerator or

999
00:49:11,480 --> 00:49:14,480
Speaker 2: press lower on the accelerator. What's been the history of that,

1000
00:49:14,600 --> 00:49:17,200
Speaker 2: Like since the beginning of the universe, there was a

1001
00:49:17,280 --> 00:49:19,719
Speaker 2: huge expansion, and then it slowed down and now it's

1002
00:49:19,760 --> 00:49:20,560
Speaker 2: picking back up again.

1003
00:49:20,640 --> 00:49:22,480
Speaker 1: Right, Yeah, that's true. And there's sort of a bunch

1004
00:49:22,520 --> 00:49:25,120
Speaker 1: of different time periods to talk about there, Like there

1005
00:49:25,160 --> 00:49:28,560
Speaker 1: was inflation very very early on, huge expansion and very

1006
00:49:28,600 --> 00:49:31,759
Speaker 1: short time scales. We don't understand what caused that at all.

1007
00:49:31,800 --> 00:49:34,480
Speaker 1: There's a few theories, the insuloton field, whatever, but it's

1008
00:49:34,520 --> 00:49:37,120
Speaker 1: a big question mark. And then after that, you know

1009
00:49:37,120 --> 00:49:38,839
Speaker 1: what we call the Big Bang, the sort of like

1010
00:49:38,960 --> 00:49:43,160
Speaker 1: more gradual expansion of the universe as it cools. We

1011
00:49:43,280 --> 00:49:46,640
Speaker 1: have pretty good models of that. We have gravity, and

1012
00:49:46,680 --> 00:49:49,000
Speaker 1: we have dark energy, we have all the other forces

1013
00:49:49,040 --> 00:49:51,719
Speaker 1: that come into play, and in that period we can

1014
00:49:51,760 --> 00:49:54,799
Speaker 1: model dark energy as constant, saying like a chunk of

1015
00:49:54,840 --> 00:49:57,400
Speaker 1: space has the same amount of potential energy, and that

1016
00:49:57,480 --> 00:50:01,360
Speaker 1: creates this repulsive field in general relative which drives the

1017
00:50:01,400 --> 00:50:04,600
Speaker 1: expansion of the universe. Remember that dark energy can be

1018
00:50:04,640 --> 00:50:07,680
Speaker 1: a constant in space, every chunk has the same amount,

1019
00:50:07,880 --> 00:50:11,520
Speaker 1: but still be a growing fraction of the universe's energy

1020
00:50:11,680 --> 00:50:15,200
Speaker 1: because other stuff is getting diluted as things expand, So

1021
00:50:15,320 --> 00:50:19,200
Speaker 1: dark energy is both constant and taking over as other

1022
00:50:19,280 --> 00:50:23,279
Speaker 1: things get more dilute. It's not exactly true, because we

1023
00:50:23,320 --> 00:50:26,320
Speaker 1: make these measurements over time we get slightly different answers,

1024
00:50:26,719 --> 00:50:29,080
Speaker 1: so nobody really knows if that's true or it needs

1025
00:50:29,080 --> 00:50:31,040
Speaker 1: a little bit of adjusting. We had a whole episode

1026
00:50:31,080 --> 00:50:34,400
Speaker 1: about early dark energy, whether dark energy was more powerful

1027
00:50:34,440 --> 00:50:37,200
Speaker 1: early on, this kind of stuff. But mostly we can

1028
00:50:37,239 --> 00:50:41,040
Speaker 1: explain the history of the universe after that first inflationary period.

1029
00:50:41,200 --> 00:50:44,440
Speaker 1: We can explain it assuming dark energy is constant, So

1030
00:50:44,480 --> 00:50:46,800
Speaker 1: that seems to be a reasonable assumption.

1031
00:50:46,520 --> 00:50:49,160
Speaker 2: Meaning that the universe is not pressing the accelerator faster,

1032
00:50:49,520 --> 00:50:50,759
Speaker 2: it's just kind of leaving it on.

1033
00:50:51,160 --> 00:50:53,880
Speaker 1: That's right. It's pressing the accelerator at the same level,

1034
00:50:54,160 --> 00:50:56,480
Speaker 1: meaning every part of space has the same amount of

1035
00:50:56,560 --> 00:51:00,400
Speaker 1: dark energy. But eventually that does take over. When you

1036
00:51:00,440 --> 00:51:03,200
Speaker 1: press the accelerator on your car. There are other things

1037
00:51:03,280 --> 00:51:06,040
Speaker 1: keeping you from going faster and faster, right, there's friction

1038
00:51:06,200 --> 00:51:08,840
Speaker 1: and this AerR, resistance whatever. That doesn't quite apply to

1039
00:51:08,880 --> 00:51:10,920
Speaker 1: this model because in this model, the level that the

1040
00:51:10,960 --> 00:51:13,640
Speaker 1: accelerator is at ends up speeding us up. It's like

1041
00:51:13,760 --> 00:51:17,640
Speaker 1: winning against the other forces. So it really is accelerating

1042
00:51:17,680 --> 00:51:20,320
Speaker 1: the expansion of the universe. So sort of two different

1043
00:51:20,320 --> 00:51:22,719
Speaker 1: ideas there. One is the amount of dark energy in

1044
00:51:22,760 --> 00:51:26,960
Speaker 1: space is constant, but because it overcomes the other things,

1045
00:51:27,200 --> 00:51:30,719
Speaker 1: it ends up accelerating the expansion of the universe.

1046
00:51:30,680 --> 00:51:34,799
Speaker 2: Meaning that the space is growing at an accelerated rate.

1047
00:51:34,920 --> 00:51:38,680
Speaker 2: But is that acceleration getting faster or is it slowing down?

1048
00:51:38,880 --> 00:51:40,160
Speaker 2: Or is it pretty constant.

1049
00:51:40,320 --> 00:51:43,640
Speaker 1: We think that acceleration itself is pretty constant, yes, and

1050
00:51:43,680 --> 00:51:45,600
Speaker 1: we can track that back through the history of the

1051
00:51:45,680 --> 00:51:47,960
Speaker 1: universe and see if that explains our history, and it

1052
00:51:48,040 --> 00:51:51,000
Speaker 1: mostly does. Again, there's some questions there about their early

1053
00:51:51,040 --> 00:51:53,840
Speaker 1: first few bits you might have read about, like different

1054
00:51:53,880 --> 00:51:57,080
Speaker 1: measurements of the Hubble constant that we can't quite reconcile.

1055
00:51:57,160 --> 00:51:59,200
Speaker 1: And that's what that's about. Is that level of acceleration

1056
00:51:59,320 --> 00:52:01,600
Speaker 1: the same all the way through time or.

1057
00:52:01,520 --> 00:52:02,799
Speaker 2: Not it is it or not?

1058
00:52:02,960 --> 00:52:05,120
Speaker 1: We think that it is, but we don't quite know

1059
00:52:05,239 --> 00:52:07,320
Speaker 1: that these measurements that we can't quite reconcile.

1060
00:52:08,000 --> 00:52:09,919
Speaker 2: I guess it's kind of the difference of whether dark

1061
00:52:10,040 --> 00:52:13,240
Speaker 2: energy is a constant, like a number in your equations

1062
00:52:13,239 --> 00:52:15,640
Speaker 2: of the universe, or is it a variable that somehow

1063
00:52:15,719 --> 00:52:18,680
Speaker 2: feeds in it itself or that maybe has a little

1064
00:52:18,680 --> 00:52:21,480
Speaker 2: button that you know, the makers of the universe are

1065
00:52:22,640 --> 00:52:23,840
Speaker 2: increasing exactly.

1066
00:52:23,960 --> 00:52:26,400
Speaker 1: Yeah, right, now, we can describe it just using a number.

1067
00:52:26,640 --> 00:52:29,560
Speaker 1: It's a cosmological constant. We don't know where that number

1068
00:52:29,600 --> 00:52:31,440
Speaker 1: comes from or why it is what it is. We

1069
00:52:31,480 --> 00:52:33,800
Speaker 1: have really no explanation for it. But we can mostly

1070
00:52:33,840 --> 00:52:36,400
Speaker 1: describe the history of the universe using just a number

1071
00:52:36,640 --> 00:52:37,520
Speaker 1: for dark energy.

1072
00:52:37,760 --> 00:52:39,600
Speaker 2: All right, Well, it sounds like the answer to the

1073
00:52:39,680 --> 00:52:43,040
Speaker 2: question of the episode is yes. It sounds like, as

1074
00:52:43,080 --> 00:52:45,160
Speaker 2: far as we know, if things stay the same with

1075
00:52:45,280 --> 00:52:49,040
Speaker 2: dark energy, are super cluster of galaxies that we live

1076
00:52:49,040 --> 00:52:52,360
Speaker 2: in will be torn apart sometime in the future.

1077
00:52:52,640 --> 00:52:56,120
Speaker 1: That's right. So our more immedia cosmic neighborhood is safe

1078
00:52:56,160 --> 00:52:59,560
Speaker 1: and probably will eventually collapse into a black hole, but

1079
00:52:59,680 --> 00:53:03,560
Speaker 1: the cluster will not be in our neighborhood forever. Dark

1080
00:53:03,640 --> 00:53:06,240
Speaker 1: energy will take over and pull us apart from it.

1081
00:53:06,239 --> 00:53:09,360
Speaker 2: It's going to be declustered, but we won't know, I

1082
00:53:09,360 --> 00:53:10,560
Speaker 2: guess until the end of time.

1083
00:53:10,760 --> 00:53:13,480
Speaker 1: That's right. So we'll do our five millionth episode at

1084
00:53:13,480 --> 00:53:15,920
Speaker 1: the end of time, and we'll answer this question definitively.

1085
00:53:16,440 --> 00:53:19,560
Speaker 2: So maybe I shouldn't call you a person, Daniel, because eventually,

1086
00:53:19,560 --> 00:53:21,840
Speaker 2: who knows, maybe aliens will come and tear you apart.

1087
00:53:22,360 --> 00:53:24,040
Speaker 2: We just have to wait and see before we call

1088
00:53:24,080 --> 00:53:24,600
Speaker 2: you a person.

1089
00:53:24,760 --> 00:53:26,440
Speaker 1: That's true. From that point of view, none of us

1090
00:53:26,440 --> 00:53:27,040
Speaker 1: are structured.

1091
00:53:27,920 --> 00:53:31,120
Speaker 2: We could all be lunch in our future, hey, fellow,

1092
00:53:31,200 --> 00:53:32,759
Speaker 2: lunch meat.

1093
00:53:32,840 --> 00:53:35,120
Speaker 1: Ashes to ashes, dust to lunch.

1094
00:53:35,120 --> 00:53:38,799
Speaker 2: And lunch to something else once the aliens digest us.

1095
00:53:39,760 --> 00:53:44,480
Speaker 2: All right, well, pretty interesting lesson to think about, not

1096
00:53:44,640 --> 00:53:47,160
Speaker 2: just like our place in the universe and how small

1097
00:53:47,160 --> 00:53:50,600
Speaker 2: we are compared to these enormous clusters of galaxies, but

1098
00:53:50,640 --> 00:53:53,880
Speaker 2: also about the permanence of the universe. Like even something

1099
00:53:54,040 --> 00:53:57,080
Speaker 2: as huge as a super cluster Lenni Kia, it may

1100
00:53:57,120 --> 00:53:59,320
Speaker 2: not be around for the entire life of the universe.

1101
00:53:59,400 --> 00:54:03,760
Speaker 1: That's right. Think about these incredibly powerful, vast forces at play,

1102
00:54:03,840 --> 00:54:08,360
Speaker 1: tugging on these galaxies with millions and billions of stars,

1103
00:54:08,760 --> 00:54:11,400
Speaker 1: all in a battle against dark energy. It's really a

1104
00:54:11,480 --> 00:54:13,960
Speaker 1: very dynamical place. If you think about the universe and

1105
00:54:14,000 --> 00:54:17,719
Speaker 1: sort of fast forward, it's slashing, it's frothen it's doing

1106
00:54:17,840 --> 00:54:18,200
Speaker 1: a lot.

1107
00:54:18,520 --> 00:54:20,960
Speaker 2: All right. We hope you enjoyed that. Thanks for joining us,

1108
00:54:22,000 --> 00:54:22,719
Speaker 2: See you next time.

1109
00:54:30,600 --> 00:54:33,400
Speaker 1: Thanks for listening, and remember that Daniel and Jorge Explain

1110
00:54:33,480 --> 00:54:36,719
Speaker 1: the Universe is a production of iHeart Radio. For more

1111
00:54:36,800 --> 00:54:41,640
Speaker 1: podcasts from iHeartRadio, visit the iHeartRadio, ap Apple podcasts, or

1112
00:54:41,680 --> 00:54:43,920
Speaker 1: wherever you listen to your favorite shows.