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Speaker 1: Ay or Hey, I have a physics version of when

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Speaker 1: you rather Oh, I'd rather not play? Not an option today?

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Speaker 1: So would you rather be blown up in a supernova

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Speaker 1: or crushed in a black hole?

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Speaker 4: Well, if I fell into a black hole, there would

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Speaker 4: be time dilation, so it sounds like it would take forever.

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Speaker 4: 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 4: I would pick live my life over and being eaten

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Speaker 4: 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 4: I'll pick the supernova again. Please. I'm crushed just trying

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Speaker 4: to blow this up.

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Speaker 2: Hi.

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Speaker 4: I'm Poorhamy cartoonists 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 4: Well, I guess if you get do you get to

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Speaker 4: choose when you get eaten by aliens? You know, if

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Speaker 4: you can choose to get it done right before you're

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Speaker 4: gonna die of natural causes, maybe that's okay, But like

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Speaker 4: 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 pop luck. That's fine.

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Speaker 4: You gotta be careful, though, do you mean like extraterrestrial

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Speaker 4: aliens or people who are you know, alien? Alien to

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Speaker 4: 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 4: Oh, you're gonna be run as you're getting.

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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 4: Oh boy, anyways, Welcome to our podcast, Daniel and Jorge

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Speaker 4: Explain the Universe, a production of iHeartRadio.

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Speaker 1: In which we take great pains and great sacrifices to

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Speaker 1: try to explain the nature of the universe to you.

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Speaker 1: We cast our minds out into that dark cosmic mystery

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Speaker 1: and wonder what's out there, who's out there, what's going

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Speaker 1: on out there? How big is it? Is it still

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Speaker 1: sloshing around, and what will be its final fate. We

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Speaker 1: want to understand the cosmic context of our very existence

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Speaker 1: because it drives the choices we make every day about

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Speaker 1: whether or not we sign ourselves up to be part

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Speaker 1: of an alien barbecue.

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Speaker 4: That's right. It is a humongous universe full of amazing

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Speaker 4: and awesome things out there that may kill you or

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Speaker 4: eat you and or inspire you to learn more about

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Speaker 4: 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 4: Yeah, it used to be there. Our context was pretty

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Speaker 4: much like the Earth, and people thought that the Sun

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Speaker 4: and the moon and the stars all revolved around the Earth.

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Speaker 4: 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 4: 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 4: Interesting, now, Daniel, do we know for sure that's not true?

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Speaker 4: 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 4: By we mean the priverurial we but have you gone

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Speaker 4: up there and touched these that made sure there's no

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Speaker 4: 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, you.

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Speaker 4: 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 4: 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 thousands 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 4: That's pretty cool. Yeah, because, as you were saying, our

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Speaker 4: understanding of where or and how we fit in this

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Speaker 4: universe keeps growing and growing, and it seems like each

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Speaker 4: time we just get more and more insignificant with 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 4: No, that makes no sense. We're insignificant specs in this

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Speaker 4: 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 4: Like being know where you're being eaten by aliens doesn't

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Speaker 4: help the fact that you're being eaten by.

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Speaker 1: Eighties still makes it worth it, still makes.

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Speaker 4: It worth it. In fact, that makes it worse. But

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Speaker 4: it does seem like we are getting smaller and smaller

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Speaker 4: in the Humerus. And literally that's true, right, because every year,

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Speaker 4: every second of the day, the universe, or our understanding

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Speaker 4: of how 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 flow 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 4: Yeah, again, I think you're using the proverbial we there.

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Speaker 4: 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.

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Speaker 4: But at least we're helping, I guess, talk about what

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Speaker 4: they've done and disseminate this information out to others. And

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Speaker 4: it's interesting when you say like that we might never

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Speaker 4: reach those places that we're seeing far far away. I'm

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Speaker 4: wonder if that's it's really true. I guess that's true

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Speaker 4: because our view of the universe is expanding at the

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Speaker 4: speed of light, and there's no way that humans could

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Speaker 4: outpaste 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. We're

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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 4: M Yeah, because the universe is expanding faster and faster

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Speaker 4: every time, every second of the day. Although we don't

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Speaker 4: know what's going to happen in the future, right, it

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Speaker 4: could be that in the far distant future or maybe tomorrow,

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Speaker 4: the universe might decide, Hey, I think I'm gonna stop

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Speaker 4: growing and I'm going to collapse back on myself, and

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Speaker 4: in which case we're going to basically visit every place

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Speaker 4: in the universe at some point.

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

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Speaker 1: bring with them all their aliens, with all their barbecue.

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Speaker 4: Tools, all their appetites. Well, maybe the big joke is

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Speaker 4: that in the end, the universe eats us 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 4: 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 4: But don't they say ignorance is bliss?

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

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Speaker 4: Maybe that's the difference between you and me and Daniel.

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Speaker 4: I'll go from 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?

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Speaker 4: Yeah, because, as we mentioned, the universe is expanding faster

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Speaker 4: and faster and faster, and that has some pretty dramatic

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Speaker 4: consequences for some of the bigger structures in the universe.

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Speaker 4: And so today on the podcast we'll be tackling the

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Speaker 4: question will our super cluster be torn apart? Sounds kind

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Speaker 4: of sad, like.

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Speaker 1: A chunk of juicy barbecue.

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Speaker 4: Well, wow, who would eat a giant supercluster of galaxies?

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

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Speaker 4: And how big does the barbecue sauce bottle need to be? Well,

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Speaker 4: this is an interesting question and so we'll dig into

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Speaker 4: it of what a super cluster is, what does it

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Speaker 4: mean for it to be torn apart, and what could

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Speaker 4: be causing it to be torn apart. But as usual,

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Speaker 4: we were wondering how many people had considered these words

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Speaker 4: together 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 4: So think about it for a second. Do you think

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Speaker 4: our supercluster will be torn apart? Here's what people have

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Speaker 4: to say.

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Speaker 1: I say no.

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Speaker 3: I believe that dark matter and dark energy will keep

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Speaker 3: it together, just like it build the supercluster that we

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Speaker 3: see today.

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Speaker 5: Well, our supercluster, if I believe right, is a collection

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Speaker 5: of galaxies that we're in kind of grouped up. So

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Speaker 5: if anything, I feel like it would get larger just

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Speaker 5: by gravitationally attracting other galaxies that are just floating out there.

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Speaker 6: If I get it's right, the galaxies of our supercluster

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Speaker 6: won't drift apart due to the expansion of the universe,

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Speaker 6: but they might dive into each other.

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Speaker 7: A supercluster is a group of galaxy. Dark energy obviously

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Speaker 7: is moving things apart. But I think the galaxy would

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Speaker 7: stay together, but that galaxies would separate from each other.

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Speaker 7: So I reckon our supercluster will be torn apart.

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Speaker 4: 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 4: 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 4: Yeah, but I guess some people mention gravity as keeping

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Speaker 4: us together instead of letting the supercluster get torn apart,

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Speaker 4: and some people mention dark matter as a way to

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Speaker 4: 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 4: 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 4: 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 4: Mane sounds good. Well, let's dive into this tasty topic

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Speaker 4: here step us through Danielle. 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 4: Yeah, because I guess if you think about just the

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Speaker 4: word structure and what it means in our everyday lives,

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Speaker 4: it basically just means like things that are clumped together, right,

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Speaker 4: or that move together, or that can be separated from

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Speaker 4: each other. And you sort of drill down into it,

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Speaker 4: like even the house you're sitting on, or the building

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Speaker 4: you're sitting on, or maybe even the car you're sitting on,

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Speaker 4: it's just a collection of loose particles being held together

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Speaker 4: by a force in the universe. Like they're not part

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Speaker 4: of the same thing. They're individual particles, but there's just

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Speaker 4: some force that keeps them all moving together.

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

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Speaker 1: 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 4: Interesting. Yeah, crowd is a good example, right, because it

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Speaker 4: may look like a cluster, or like a from a

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Speaker 4: farm might look like a clump of things, but really

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Speaker 4: there's nothing keeping those individual people or structures together.

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Speaker 3: Right.

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Speaker 4: 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 4: Yeah, whereas maybe, like for the planet Earth, all the

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Speaker 4: rocks on planet Earth are being kept from flying away

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Speaker 4: 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. It's incredible to think about,

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Speaker 1: like how organized the universe is. And there's a whole

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Speaker 1: group of philosophers who study this kind of thing and

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Speaker 1: wonder like why do we have structure these distances and

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Speaker 1: not other distances, and does it bubble up from the

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

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

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

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Speaker 1: our cosmic neighborhood? And so we can like zoom out

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

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

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Speaker 4: Yeah, because I guess you know, sort of like you

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Speaker 4: were saying, the atoms in my body make up my structure,

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Speaker 4: but they're all also kind of being pulled by the

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Speaker 4: gravity of the Earth, right, So like, is it more

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Speaker 4: part of my structure or are all the atoms in

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Speaker 4: my body more part of the earth structure? And even

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Speaker 4: like the atoms in my body are being pulled by

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Speaker 4: the gravity of the Sun, but we wouldn't say, like, hey,

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Speaker 4: I'm just me and the Sun are one, even though

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Speaker 4: if you sort of follow the chain of forces that

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Speaker 4: 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're like these groups of

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Speaker 1: 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 4: Do we know that's for sure? Or I mean, like,

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Speaker 4: do we know which stars are near us? And would

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Speaker 4: you say maybe they're too far away for their gravity

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Speaker 4: 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 like how the stars are moving. For example,

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

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Speaker 1: were all formed together and they're moving together. 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 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 4: Now are they would you say they're a structure or

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Speaker 4: are they just moving together like a crowd or like

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Speaker 4: a wisp of cloud.

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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 some times

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

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

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

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Speaker 1: pulled 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 4: So you would say, like after our solar system, the

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Speaker 4: next structure is a galaxy. You wouldn't maybe call the

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Speaker 4: arms of a galaxy a structure.

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

439
00:21:25,240 --> 00:21:28,280
Speaker 1: the galaxy are not physical structures. It's not like the

440
00:21:28,359 --> 00:21:32,240
Speaker 1: same stars are moving through those arms. The arms are

441
00:21:32,240 --> 00:21:35,080
Speaker 1: a wave through the stars. Like when you go to

442
00:21:35,119 --> 00:21:38,120
Speaker 1: a football game and people do the wave. That wave

443
00:21:38,160 --> 00:21:40,399
Speaker 1: itself is not a structure. It's just an arrangement of

444
00:21:40,440 --> 00:21:42,960
Speaker 1: the people as they move up and down. Galaxy arms

445
00:21:42,960 --> 00:21:45,720
Speaker 1: are the same way. They're not physical structures. They're just

446
00:21:45,840 --> 00:21:49,320
Speaker 1: density waves. So they're not actually holding themselves together, just

447
00:21:49,320 --> 00:21:51,520
Speaker 1: like waves in the ocean are not really structures. They're

448
00:21:51,560 --> 00:21:52,439
Speaker 1: not bound together.

449
00:21:53,440 --> 00:21:56,000
Speaker 4: And so our solar system, our star is not part

450
00:21:56,040 --> 00:21:58,520
Speaker 4: of a like a mini dwarf galaxy. We're just out

451
00:21:58,560 --> 00:22:00,480
Speaker 4: in the larger Milky Way galaxy.

452
00:22:00,640 --> 00:22:03,320
Speaker 1: Yep, We're just floating in the bathtub of the Milky Way,

453
00:22:03,640 --> 00:22:06,520
Speaker 1: along with hundreds of billions of other stars.

454
00:22:06,200 --> 00:22:10,280
Speaker 4: And potentially aliens that might eat us one of us. Right,

455
00:22:10,320 --> 00:22:13,200
Speaker 4: it sounds like a dangerous hot tub. Well, let's dig

456
00:22:13,240 --> 00:22:16,199
Speaker 4: into the next level of structure in the universe and

457
00:22:16,320 --> 00:22:19,320
Speaker 4: let's see how big we can go. How far can

458
00:22:19,359 --> 00:22:22,520
Speaker 4: we add or recognize structure in the universe and what's

459
00:22:22,560 --> 00:22:24,600
Speaker 4: going to happen to all that structure at the end

460
00:22:24,640 --> 00:22:27,640
Speaker 4: of time. So let's dig into that. But first let's

461
00:22:27,680 --> 00:22:28,679
Speaker 4: take a quick break.

462
00:22:32,680 --> 00:22:35,600
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513
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515
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519
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521
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522
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530
00:26:10,400 --> 00:26:13,120
Speaker 4: All right, we're asking the question will our super cluster

531
00:26:13,320 --> 00:26:16,400
Speaker 4: be torn apart? Which kind of sounds like an oxymoron

532
00:26:16,760 --> 00:26:20,399
Speaker 4: question or a contradictory question. Will something that's clustered together

533
00:26:20,440 --> 00:26:21,520
Speaker 4: and not be clustered together.

534
00:26:22,440 --> 00:26:24,359
Speaker 1: Yeah, in the end, we're going to learn that astronomers

535
00:26:24,359 --> 00:26:28,199
Speaker 1: are arguing about how to define a supercluster, and some

536
00:26:28,359 --> 00:26:31,280
Speaker 1: definitions make the answer obvious, and some definitions make the

537
00:26:31,320 --> 00:26:33,480
Speaker 1: answer to this question very fuzzy.

538
00:26:33,640 --> 00:26:36,200
Speaker 4: But we were talking about how you know things, how

539
00:26:36,240 --> 00:26:39,359
Speaker 4: do you define structures, And it seems like sometimes, like

540
00:26:39,400 --> 00:26:41,160
Speaker 4: in a cloud or in a crowd, things might look

541
00:26:41,200 --> 00:26:43,600
Speaker 4: like they're together, but really they can fall apart at

542
00:26:43,600 --> 00:26:45,600
Speaker 4: any point, so you wouldn't call that a structure. But

543
00:26:45,760 --> 00:26:48,280
Speaker 4: like the atoms in your body or the atoms in

544
00:26:48,320 --> 00:26:50,560
Speaker 4: the building or car you're sitting on, they're helped together

545
00:26:50,600 --> 00:26:54,840
Speaker 4: pretty tightly by forces, and they basically sort of ignore

546
00:26:54,920 --> 00:26:57,280
Speaker 4: other forces in favor of the forces that are holding

547
00:26:57,320 --> 00:26:59,600
Speaker 4: them together. And so maybe that's why we call them.

548
00:26:59,560 --> 00:27:02,240
Speaker 1: A struck that's right. And it can be gravitational, or

549
00:27:02,280 --> 00:27:04,800
Speaker 1: it can be electromagnetic, or it can be the strong

550
00:27:04,880 --> 00:27:08,199
Speaker 1: force that forms these structures, like the proton is a

551
00:27:08,240 --> 00:27:10,439
Speaker 1: structure of the strong force, and the atom is a

552
00:27:10,440 --> 00:27:15,000
Speaker 1: structure of electromagnetism. But at larger distances, basically anything bigger

553
00:27:15,040 --> 00:27:18,320
Speaker 1: than a few meters, it's mostly gravity that takes over

554
00:27:18,760 --> 00:27:21,320
Speaker 1: because the other forces are so powerful that they tend

555
00:27:21,320 --> 00:27:24,600
Speaker 1: to neutralize themselves. Anything that has a large positive or

556
00:27:24,640 --> 00:27:27,399
Speaker 1: negative charge is going to attract the opposite charge and

557
00:27:27,480 --> 00:27:30,640
Speaker 1: end up neutralizing itself. But over the large distances, it's

558
00:27:30,720 --> 00:27:35,240
Speaker 1: gravity that forms structure because gravity cannot be neutralized. Essentially,

559
00:27:35,240 --> 00:27:38,159
Speaker 1: it's only attractive. There are a few scenarios we can

560
00:27:38,200 --> 00:27:41,240
Speaker 1: talk about with like repulsive gravity, and dark energy might

561
00:27:41,320 --> 00:27:43,720
Speaker 1: be an example of that, But on the whole, gravity

562
00:27:43,760 --> 00:27:46,359
Speaker 1: is attractive, and so it's the force that's responsible for

563
00:27:46,520 --> 00:27:48,720
Speaker 1: most of the structure we think about in the universe.

564
00:27:49,040 --> 00:27:51,479
Speaker 4: Mm yeah, like after about the size of a planet,

565
00:27:51,560 --> 00:27:54,280
Speaker 4: there's no other forces really at play in the universe

566
00:27:54,440 --> 00:27:56,440
Speaker 4: that we know of. Maybe there's something hitting out there.

567
00:27:56,520 --> 00:27:58,359
Speaker 4: Could dark matter be some kind of new force.

568
00:28:00,280 --> 00:28:02,159
Speaker 1: Energy is definitely in that category. We don't know if

569
00:28:02,160 --> 00:28:06,119
Speaker 1: it's a manifestation of gravity due to the quantum energy

570
00:28:06,119 --> 00:28:08,400
Speaker 1: of space or something totally else and.

571
00:28:08,400 --> 00:28:11,320
Speaker 4: Weird All right, Well, we talked about how we're part

572
00:28:11,359 --> 00:28:14,240
Speaker 4: of a solar system, and the Solar system is part

573
00:28:14,240 --> 00:28:17,320
Speaker 4: of a bigger structure called the Milky Way Galaxy. What's

574
00:28:17,320 --> 00:28:17,760
Speaker 4: after that?

575
00:28:17,880 --> 00:28:20,560
Speaker 1: So the galaxies aren't just like floating out in space,

576
00:28:20,880 --> 00:28:24,200
Speaker 1: sprinkled evenly through the universe. They tend to clump together,

577
00:28:24,320 --> 00:28:26,320
Speaker 1: and they can clump together into something that we call

578
00:28:26,440 --> 00:28:30,440
Speaker 1: a galactic group or a group of galaxies. In our galaxy,

579
00:28:30,480 --> 00:28:32,360
Speaker 1: the Milky Way is part of a group we call

580
00:28:32,440 --> 00:28:35,880
Speaker 1: the local Group very cleverly, and it has about fifty

581
00:28:35,960 --> 00:28:39,680
Speaker 1: ish galaxies in it. The biggest one is Andromeda, which

582
00:28:39,720 --> 00:28:41,400
Speaker 1: is also the nearest one to us.

583
00:28:41,600 --> 00:28:44,360
Speaker 4: And so these are galaxies that are not just neros

584
00:28:44,440 --> 00:28:47,840
Speaker 4: out of convenience. We're actually sort of locked together with

585
00:28:47,920 --> 00:28:50,840
Speaker 4: them in some sort of gravitational dance. Right.

586
00:28:50,960 --> 00:28:53,800
Speaker 1: Yeah. We think that these galaxies are holding themselves together.

587
00:28:53,880 --> 00:28:57,680
Speaker 1: They're like a single gravitational object. They are orbiting the

588
00:28:57,720 --> 00:29:01,080
Speaker 1: center of mass of all of these galaxies. And people

589
00:29:01,120 --> 00:29:04,360
Speaker 1: hear a lot that the universe is expanding and everything

590
00:29:04,400 --> 00:29:06,560
Speaker 1: is getting farther and farther away. And that's true sort

591
00:29:06,560 --> 00:29:08,880
Speaker 1: of on the whole when you look at vast distances,

592
00:29:09,360 --> 00:29:12,640
Speaker 1: but nearby gravity is powerful enough to hold us together,

593
00:29:13,080 --> 00:29:16,560
Speaker 1: and that's happening also with these galaxies. That's why, for example,

594
00:29:16,800 --> 00:29:19,960
Speaker 1: we are headed towards the Andromeda galaxy and in a

595
00:29:19,960 --> 00:29:23,360
Speaker 1: few billion years our galaxy and Andromeda will collide and

596
00:29:23,440 --> 00:29:26,240
Speaker 1: will merge because gravity is winning the battle over the

597
00:29:26,280 --> 00:29:29,280
Speaker 1: expansion of space. So this local group, we think is

598
00:29:29,320 --> 00:29:32,480
Speaker 1: a thing. It's a structure that gravity is powerful enough

599
00:29:32,520 --> 00:29:33,320
Speaker 1: to hold together.

600
00:29:33,520 --> 00:29:35,960
Speaker 4: And now, what kind of shape does this local group have?

601
00:29:36,200 --> 00:29:38,200
Speaker 4: Is it like a disk like our solar system or

602
00:29:38,280 --> 00:29:40,120
Speaker 4: the galaxy or is it still kind of like a

603
00:29:40,160 --> 00:29:43,360
Speaker 4: fuzzy cloud of things moving all in all directions.

604
00:29:43,520 --> 00:29:46,200
Speaker 1: It doesn't really have a great shape because it's sort

605
00:29:46,200 --> 00:29:49,680
Speaker 1: of weirdly distributed. Like there's Andromeda, then there's the Milky Way,

606
00:29:49,760 --> 00:29:53,200
Speaker 1: there's another galaxy called the Triangular Galaxy, and the rest

607
00:29:53,240 --> 00:29:56,120
Speaker 1: of it is like a sprinkle of little tiny galaxies.

608
00:29:56,440 --> 00:29:59,000
Speaker 1: So they're not like nicely organized into a flat disk

609
00:29:59,400 --> 00:30:02,040
Speaker 1: or anything like that. It's just sort of like a blob.

610
00:30:02,360 --> 00:30:04,520
Speaker 4: Or at least not yet. Right, maybe if you fast

611
00:30:04,560 --> 00:30:07,000
Speaker 4: forward a few billion years, things will even out into

612
00:30:07,000 --> 00:30:09,000
Speaker 4: a disk, because that's what things do in space. They

613
00:30:09,520 --> 00:30:11,840
Speaker 4: organize themselves into discs, right.

614
00:30:11,920 --> 00:30:13,440
Speaker 1: They do tend to do that if you give them

615
00:30:13,560 --> 00:30:17,240
Speaker 1: enough time, because they're spinning and gravity will collapse everything

616
00:30:17,280 --> 00:30:19,640
Speaker 1: down eventually, except along the plane of their spin. They

617
00:30:19,640 --> 00:30:22,200
Speaker 1: can resist gravity a little bit, which is why they

618
00:30:22,280 --> 00:30:24,640
Speaker 1: end up as discs, so in sort of one direction

619
00:30:24,720 --> 00:30:26,920
Speaker 1: they can collapse, and along the other two dimensions on

620
00:30:26,960 --> 00:30:29,520
Speaker 1: that plane they end up sort of spinning around, which

621
00:30:29,560 --> 00:30:31,320
Speaker 1: is how you get a flat solar system and a

622
00:30:31,320 --> 00:30:35,120
Speaker 1: flat galaxy. Eventually, though, we think that gravity will win,

623
00:30:35,280 --> 00:30:37,280
Speaker 1: that those things will bump against each other and lose

624
00:30:37,320 --> 00:30:41,240
Speaker 1: angular momentum, or they will radiate gravitational waves and lose

625
00:30:41,280 --> 00:30:44,800
Speaker 1: that energy, and eventually we think that gravitationally bound objects

626
00:30:44,880 --> 00:30:48,040
Speaker 1: will all collapse together, first into one big galaxy and

627
00:30:48,080 --> 00:30:50,800
Speaker 1: then eventually just into one big black hole yike.

628
00:30:51,080 --> 00:30:54,200
Speaker 4: But before that happens, we can see other kinds of structures, right,

629
00:30:54,200 --> 00:30:57,320
Speaker 4: bigger structures, So like a group of galaxies can be

630
00:30:57,360 --> 00:30:59,960
Speaker 4: part of a larger kind of thing.

631
00:31:00,320 --> 00:31:02,280
Speaker 1: Yeah, So we call this either a group or a

632
00:31:02,320 --> 00:31:05,479
Speaker 1: cluster of galaxies, And depending on the size, like if

633
00:31:05,480 --> 00:31:08,120
Speaker 1: there aren't that many galaxies in it, like in ours,

634
00:31:08,120 --> 00:31:10,720
Speaker 1: we call it a group. If there are more galaxies

635
00:31:10,760 --> 00:31:13,240
Speaker 1: in it, you can call it a cluster. And so nearby,

636
00:31:13,360 --> 00:31:16,400
Speaker 1: for example, is the Virgo cluster. It has more than

637
00:31:16,440 --> 00:31:19,120
Speaker 1: a thousand galaxies that are like the Milky Way, so

638
00:31:19,160 --> 00:31:22,320
Speaker 1: it's much much bigger than the local group. And we

639
00:31:22,320 --> 00:31:24,720
Speaker 1: think that is also like an object that has structure,

640
00:31:24,920 --> 00:31:26,960
Speaker 1: we think it's going to hold itself together, that there's

641
00:31:27,120 --> 00:31:29,280
Speaker 1: enough gravity to keep itself together.

642
00:31:29,560 --> 00:31:32,600
Speaker 4: Yeah, isn't it pretty amazing to think? Even at these numbers,

643
00:31:32,640 --> 00:31:34,520
Speaker 4: like a thousand, A thousand doesn't sound like a lot,

644
00:31:34,640 --> 00:31:38,360
Speaker 4: But if you imagine a thousand galaxies like the Milky Way,

645
00:31:38,600 --> 00:31:41,080
Speaker 4: that is sort of mind blowing. Right, Like, we think

646
00:31:41,120 --> 00:31:44,240
Speaker 4: our galaxy is pretty huge and we'll probably never get

647
00:31:44,280 --> 00:31:46,720
Speaker 4: to the other side of it, and has billions of stars.

648
00:31:47,160 --> 00:31:49,320
Speaker 4: Now imagine there are thousands of these things out there

649
00:31:49,320 --> 00:31:49,760
Speaker 4: in space.

650
00:31:49,840 --> 00:31:52,000
Speaker 1: And the thing that blows my mind is the planets. Right,

651
00:31:52,080 --> 00:31:54,400
Speaker 1: even in our galaxy, we know there are hundreds of

652
00:31:54,480 --> 00:31:58,000
Speaker 1: billions of stars, and a significant fraction of those have

653
00:31:58,160 --> 00:32:01,200
Speaker 1: Earth like planets. You know, planet about the same size,

654
00:32:01,240 --> 00:32:04,200
Speaker 1: with about the same surface temperature. We don't really know

655
00:32:04,280 --> 00:32:06,840
Speaker 1: that much more about them, but like, that's a lot

656
00:32:06,920 --> 00:32:10,400
Speaker 1: of Earth like planets. We're talking about tens of billions

657
00:32:10,480 --> 00:32:13,240
Speaker 1: just in our galaxy, and now multiply that by a

658
00:32:13,320 --> 00:32:17,120
Speaker 1: thousand for all the galaxies in the Virgo cluster. It's

659
00:32:17,120 --> 00:32:19,600
Speaker 1: hard to keep track of, like all the places aliens

660
00:32:19,640 --> 00:32:21,479
Speaker 1: could be sharpening their barbecue tools.

661
00:32:21,760 --> 00:32:24,640
Speaker 4: Yeah, so let's not think about that. Man, Yeah, I

662
00:32:24,720 --> 00:32:25,280
Speaker 4: agree with you.

663
00:32:27,600 --> 00:32:30,280
Speaker 1: But the Virgo cluster is like the biggest thing around.

664
00:32:30,320 --> 00:32:33,440
Speaker 1: There are other little galaxy groups nearby, like there's the

665
00:32:33,640 --> 00:32:36,719
Speaker 1: M eighty one group and the Sculptor group, other little

666
00:32:36,800 --> 00:32:39,320
Speaker 1: groups of galaxies that are sort of in this sort

667
00:32:39,320 --> 00:32:41,840
Speaker 1: of the same size as our group. But the Virgo

668
00:32:41,880 --> 00:32:45,160
Speaker 1: cluster is like the big Papa and Mama galaxy cluster nearby.

669
00:32:45,240 --> 00:32:47,960
Speaker 1: It's like the most massive thing in the nearby universe.

670
00:32:48,160 --> 00:32:51,120
Speaker 4: Well, it's interesting with gravity, I feel, because gravity doesn't

671
00:32:51,120 --> 00:32:54,400
Speaker 4: have a limit, right, Like there's no distance limit for gravity,

672
00:32:54,680 --> 00:32:57,320
Speaker 4: Like this Virgo cluster is super dup or duper far

673
00:32:57,360 --> 00:33:00,560
Speaker 4: away from us. But technically speaking, like the atoms in

674
00:33:00,600 --> 00:33:03,240
Speaker 4: my body and in your body and everybody's bodies is

675
00:33:03,280 --> 00:33:07,600
Speaker 4: being tugged pulled by the gravity of that cluster is

676
00:33:07,640 --> 00:33:08,320
Speaker 4: super far away.

677
00:33:08,400 --> 00:33:11,680
Speaker 1: That's right. Everything in the universe technically is pulling on

678
00:33:11,720 --> 00:33:14,480
Speaker 1: you gravitationally. Gravity does have this weakness though, which is

679
00:33:14,760 --> 00:33:18,880
Speaker 1: that its power drops as the distance squared. So if

680
00:33:18,920 --> 00:33:21,800
Speaker 1: you're twice as far away from something, its gravity goes

681
00:33:21,840 --> 00:33:24,520
Speaker 1: down by a factor of four. If you're ten times

682
00:33:24,560 --> 00:33:27,120
Speaker 1: further away, then the gravity goes down by a factor

683
00:33:27,160 --> 00:33:29,000
Speaker 1: of one hundred, and this gets to be a very

684
00:33:29,040 --> 00:33:33,240
Speaker 1: powerful obstacle to gravity as distances grow large. And so

685
00:33:33,360 --> 00:33:35,760
Speaker 1: the Virgo cluster, even though it's the most massive thing

686
00:33:35,800 --> 00:33:39,360
Speaker 1: in the nearby universe, it's like fifty or sixty million

687
00:33:39,680 --> 00:33:44,000
Speaker 1: light years away. That's a big distance to square, right,

688
00:33:44,240 --> 00:33:47,000
Speaker 1: So its gravity is really tiny, which is why it's

689
00:33:47,040 --> 00:33:49,920
Speaker 1: not obvious whether our little group, the local group, and

690
00:33:49,960 --> 00:33:52,640
Speaker 1: the Virgo cluster should be considered as part of some

691
00:33:52,760 --> 00:33:53,640
Speaker 1: larger object.

692
00:33:53,880 --> 00:33:56,240
Speaker 4: Right. It gets attenuated a lot, it weakened a lot

693
00:33:56,280 --> 00:33:58,560
Speaker 4: by distance, but it's still there, right, Like I feel

694
00:33:58,560 --> 00:34:02,040
Speaker 4: like like I'm sensing I have this feeling of like

695
00:34:02,680 --> 00:34:05,920
Speaker 4: a small tendril of force that pulls me from the

696
00:34:05,960 --> 00:34:09,560
Speaker 4: atoms in my body to the Virgo cluster, right, And

697
00:34:09,640 --> 00:34:11,480
Speaker 4: it also kind of depends like, what if the Virgo

698
00:34:11,560 --> 00:34:16,000
Speaker 4: cluster was super duper massive, right, we would eventually feel

699
00:34:16,239 --> 00:34:17,160
Speaker 4: their gravity.

700
00:34:17,320 --> 00:34:19,719
Speaker 1: Yeah, that's true, and we do feel it's gravity. You're

701
00:34:19,719 --> 00:34:22,320
Speaker 1: absolutely right. I feel like you're just sort of preparing

702
00:34:22,360 --> 00:34:24,239
Speaker 1: an argument for when the aliens come and you're like,

703
00:34:24,280 --> 00:34:26,440
Speaker 1: hey man, we're all part of the same thing, and

704
00:34:26,520 --> 00:34:28,600
Speaker 1: we can feel your gravity, and we do and we

705
00:34:28,680 --> 00:34:31,560
Speaker 1: can feel that gravity. And there's another way in which

706
00:34:31,560 --> 00:34:34,239
Speaker 1: we are connected to those objects. Right now, we're just

707
00:34:34,280 --> 00:34:37,680
Speaker 1: thinking mostly about the stars, the things that shine brightly,

708
00:34:37,800 --> 00:34:40,759
Speaker 1: but there are these filaments that connect us to the

709
00:34:40,880 --> 00:34:44,840
Speaker 1: other galaxies. Like between us and Andrama is not empty space.

710
00:34:44,920 --> 00:34:49,360
Speaker 1: There's this filament, this string of both matter like hydrogen atoms,

711
00:34:49,360 --> 00:34:52,719
Speaker 1: et cetera, and also dark matter. So it's not like

712
00:34:52,800 --> 00:34:55,839
Speaker 1: a bunch of dots out in space. These galaxies they're

713
00:34:55,840 --> 00:34:59,279
Speaker 1: connected to each other. It's part of some huge cosmic

714
00:34:59,360 --> 00:35:02,239
Speaker 1: web where the other parts are more invisible because they're

715
00:35:02,280 --> 00:35:02,920
Speaker 1: not glowing.

716
00:35:03,560 --> 00:35:05,840
Speaker 4: Yeah, it's sort of like a spider's web, right the universe.

717
00:35:05,920 --> 00:35:07,520
Speaker 4: Like if you look at a picture of the universe

718
00:35:07,719 --> 00:35:09,839
Speaker 4: and all the stars in it, the stars, even though

719
00:35:09,840 --> 00:35:12,640
Speaker 4: they're pinpoints, they sort of don't look like a random

720
00:35:12,680 --> 00:35:15,439
Speaker 4: white noise. They sort of look like a spider's web

721
00:35:15,520 --> 00:35:16,319
Speaker 4: kind of mm hmm.

722
00:35:16,880 --> 00:35:20,400
Speaker 1: And in between those dots there really is stuff. You know,

723
00:35:20,520 --> 00:35:23,719
Speaker 1: galaxies form in certain locations because that happens to be

724
00:35:23,800 --> 00:35:26,400
Speaker 1: where there was a little bit more dark matter. So

725
00:35:26,440 --> 00:35:28,840
Speaker 1: there's like a blob of dark matter there that's gathered

726
00:35:28,880 --> 00:35:33,160
Speaker 1: together enough light to start fusion going in those stars,

727
00:35:33,280 --> 00:35:35,799
Speaker 1: but between them there are these filaments of gas and

728
00:35:35,920 --> 00:35:39,440
Speaker 1: dark matter still flowing into those halos. So you could

729
00:35:39,440 --> 00:35:41,960
Speaker 1: think about it like a network of lakes with rivers

730
00:35:42,000 --> 00:35:45,000
Speaker 1: flowing into them, still filling them up. So galaxies are

731
00:35:45,040 --> 00:35:49,360
Speaker 1: still gathering dark matter and gas from these filaments. Structure

732
00:35:49,360 --> 00:35:53,000
Speaker 1: there is still sort of forming. Even though fourteen billion

733
00:35:53,120 --> 00:35:55,839
Speaker 1: years have gone by, Things are still happening out there

734
00:35:55,840 --> 00:35:56,480
Speaker 1: in the universe.

735
00:35:57,280 --> 00:35:59,160
Speaker 4: I guess if there's a big cloud of something like

736
00:35:59,239 --> 00:36:01,760
Speaker 4: hydrogen out there in the middle of empty space, gravity

737
00:36:01,800 --> 00:36:04,880
Speaker 4: would be pulling it together, that cloud together into a

738
00:36:04,880 --> 00:36:07,719
Speaker 4: smaller cloud, and then our gravity would be and the

739
00:36:07,840 --> 00:36:10,040
Speaker 4: gravity of other clusters would be trying to suck that

740
00:36:10,120 --> 00:36:12,759
Speaker 4: gas towards them. And so that's why maybe you get

741
00:36:12,760 --> 00:36:15,879
Speaker 4: these tendrils, these sort of like tentacles of gas out

742
00:36:15,880 --> 00:36:18,040
Speaker 4: there in space, because they're being stretched out and sucked

743
00:36:18,080 --> 00:36:20,200
Speaker 4: into the different galaxies.

744
00:36:19,719 --> 00:36:22,680
Speaker 1: Exactly, and mostly it's the dark matter doing that. Remember,

745
00:36:22,719 --> 00:36:26,240
Speaker 1: we only see the visible matter, but that's twenty percent

746
00:36:26,440 --> 00:36:28,880
Speaker 1: of the matter that's out there, most of the gravity

747
00:36:28,880 --> 00:36:31,719
Speaker 1: in the universe. Most of those tendrils you feel from

748
00:36:31,719 --> 00:36:34,640
Speaker 1: the other cluster are actually from the dark matter in

749
00:36:34,680 --> 00:36:37,160
Speaker 1: that cluster. Because that's most of the matter and so

750
00:36:37,320 --> 00:36:39,880
Speaker 1: most of the gravity in the universe. Like, the reason

751
00:36:39,880 --> 00:36:42,200
Speaker 1: we have a galaxy here and not somewhere else is

752
00:36:42,239 --> 00:36:45,239
Speaker 1: because there was dark matter to form this structure. It

753
00:36:45,280 --> 00:36:48,120
Speaker 1: created this like gravitational well, the sort of lake to

754
00:36:48,200 --> 00:36:50,920
Speaker 1: pull all the other rivers of matter into it.

755
00:36:51,160 --> 00:36:54,880
Speaker 4: Cool Well, after a cluster of galaxies, what's next?

756
00:36:55,080 --> 00:36:57,759
Speaker 1: So what's next is a little bit controversial, and in

757
00:36:57,760 --> 00:36:59,399
Speaker 1: the last ten years or so there's been a lot

758
00:36:59,400 --> 00:37:02,200
Speaker 1: of argument about it. But there's a group of astronomers

759
00:37:02,200 --> 00:37:04,719
Speaker 1: out there that say that all these clusters and these

760
00:37:04,760 --> 00:37:08,319
Speaker 1: little groups can be gathered together into something bigger, called

761
00:37:08,400 --> 00:37:12,160
Speaker 1: a supercluster. The supercluster would take like the Virgo cluster

762
00:37:12,640 --> 00:37:15,040
Speaker 1: and our little group, and a bunch of other things,

763
00:37:15,080 --> 00:37:18,200
Speaker 1: including like the Great Attractor and the Normal cluster and

764
00:37:18,239 --> 00:37:22,160
Speaker 1: the Centauris cluster and many others into some huge object

765
00:37:22,200 --> 00:37:24,759
Speaker 1: that has like one hundred thousand galaxies in it.

766
00:37:24,960 --> 00:37:29,160
Speaker 4: Right, And this supercluster is called the lani Kiak supercluster. Right.

767
00:37:29,239 --> 00:37:32,160
Speaker 1: Yeah. It's a Hawaiian word that means immense heaven, and

768
00:37:32,200 --> 00:37:35,080
Speaker 1: it was defined in like twenty fourteen when a bunch

769
00:37:35,080 --> 00:37:37,720
Speaker 1: of astronomers looked at the velocity of all these things

770
00:37:37,760 --> 00:37:39,879
Speaker 1: and said, you know what, all these things are sort

771
00:37:39,880 --> 00:37:43,719
Speaker 1: of like falling towards themselves, and there's another blob of

772
00:37:43,760 --> 00:37:47,279
Speaker 1: stuff over there that's falling towards themselves. And so they

773
00:37:47,400 --> 00:37:49,280
Speaker 1: figured out how to sort of like draw a line

774
00:37:49,320 --> 00:37:52,360
Speaker 1: between one set of blobs and another set of blobs,

775
00:37:52,360 --> 00:37:54,880
Speaker 1: and they said, we're in this blob over here.

776
00:37:55,200 --> 00:37:55,520
Speaker 9: Mmm.

777
00:37:56,080 --> 00:37:58,799
Speaker 4: I see. But can you make the mathematical calculation, like

778
00:37:59,120 --> 00:38:03,440
Speaker 4: if you compute the gravity that we're feeling between these clusters,

779
00:38:04,440 --> 00:38:06,919
Speaker 4: does it really work out that you can group these

780
00:38:07,360 --> 00:38:11,200
Speaker 4: superclusters as one or is it more like an illusion

781
00:38:11,280 --> 00:38:13,719
Speaker 4: like a wisp of cloud or a crowd of people

782
00:38:13,760 --> 00:38:14,280
Speaker 4: in a park.

783
00:38:14,440 --> 00:38:16,919
Speaker 1: Yeah, that's exactly the question, and that's really what we're

784
00:38:17,160 --> 00:38:20,879
Speaker 1: answering today is what is the future of this supercluster?

785
00:38:21,080 --> 00:38:23,400
Speaker 1: Is it going to hold itself together or is it

786
00:38:23,440 --> 00:38:25,920
Speaker 1: going to get torn apart? Because we've been talking about

787
00:38:25,920 --> 00:38:29,320
Speaker 1: gravity so far, but there's another force at play here,

788
00:38:29,400 --> 00:38:32,399
Speaker 1: and that's dark energy. If it was only gravity, then

789
00:38:32,440 --> 00:38:35,680
Speaker 1: this thing would collapse landi Ko would definitely fall into

790
00:38:35,800 --> 00:38:38,840
Speaker 1: one big object and maybe form one super galaxy and

791
00:38:38,880 --> 00:38:42,480
Speaker 1: one super black hole. There is enough gravity if the

792
00:38:42,560 --> 00:38:45,799
Speaker 1: universe wasn't expanding to pull this thing together, like it's

793
00:38:45,840 --> 00:38:49,680
Speaker 1: already right now falling inwards. Everything in the Lanti Kia

794
00:38:49,760 --> 00:38:54,000
Speaker 1: Supercluster has an overall in falling velocity. But there's another

795
00:38:54,040 --> 00:38:56,360
Speaker 1: player on this stage, right, which is the expansion of

796
00:38:56,400 --> 00:38:59,520
Speaker 1: the universe. And this has a very different behavior as

797
00:38:59,560 --> 00:39:02,799
Speaker 1: distances grow large. Like gravity gets weaker and weaker as

798
00:39:02,840 --> 00:39:06,320
Speaker 1: distances grow large. But dark energy, this accelerating expansion of

799
00:39:06,360 --> 00:39:09,960
Speaker 1: the universe, gets more powerful as distances grow large. So

800
00:39:10,000 --> 00:39:12,680
Speaker 1: at some point it takes over. There's like a crossover

801
00:39:12,760 --> 00:39:14,759
Speaker 1: point where dark energy starts to win.

802
00:39:15,040 --> 00:39:17,319
Speaker 4: Well, let's dig into that, Giuse. That is the main

803
00:39:17,400 --> 00:39:19,560
Speaker 4: question of the episode. Now we are in the Lenni

804
00:39:19,600 --> 00:39:22,800
Speaker 4: Kia Supercluster, and so the question is is something tearing

805
00:39:22,920 --> 00:39:26,319
Speaker 4: it apart. It's the biggest structure in the universe. And

806
00:39:26,400 --> 00:39:30,080
Speaker 4: so Danny, you're saying that maybe dark energy is tearing

807
00:39:30,080 --> 00:39:33,000
Speaker 4: it apart, or maybe at least fraying it at the edges.

808
00:39:33,239 --> 00:39:35,800
Speaker 1: Yeah, dark energy is definitely working to tear it apart.

809
00:39:35,920 --> 00:39:38,000
Speaker 1: And listeners right in all the time and ask about

810
00:39:38,120 --> 00:39:41,239
Speaker 1: dark energy and have this idea sometimes that dark energy

811
00:39:41,280 --> 00:39:44,080
Speaker 1: is something happening at the edges of the universe, that

812
00:39:44,120 --> 00:39:46,680
Speaker 1: there's something pulling on us from the outside, or that

813
00:39:46,760 --> 00:39:50,440
Speaker 1: maybe the expansion is only happening out there between galaxies,

814
00:39:50,480 --> 00:39:53,360
Speaker 1: but the expansion is happening everywhere. Every chunk of space

815
00:39:53,520 --> 00:39:56,759
Speaker 1: is expanding. Like the Hubble constant is a measure of

816
00:39:56,800 --> 00:40:01,040
Speaker 1: how fast things are expanding, and it's like seventy kilometers

817
00:40:01,080 --> 00:40:04,239
Speaker 1: per second per megaparsek, which is sort of a hard

818
00:40:04,239 --> 00:40:05,880
Speaker 1: thing to get your mind around, but really it just

819
00:40:05,960 --> 00:40:08,920
Speaker 1: means that like every megaparsec, which is like three light years,

820
00:40:09,360 --> 00:40:13,440
Speaker 1: grows by about seventy kilometers every second, and that happens

821
00:40:13,480 --> 00:40:16,440
Speaker 1: everywhere in space. If you have a smaller distance, like

822
00:40:16,440 --> 00:40:18,520
Speaker 1: the distance between the Earth and the Sun, which is

823
00:40:18,560 --> 00:40:21,520
Speaker 1: only a few tens of millions of miles, it would

824
00:40:21,600 --> 00:40:25,960
Speaker 1: grow by a much smaller amount than seventy kilometers every second.

825
00:40:26,120 --> 00:40:28,239
Speaker 1: So that expansion is happening everywhere, but it's sort of

826
00:40:28,280 --> 00:40:32,000
Speaker 1: faint and weak. It's not very strong over short distances,

827
00:40:32,040 --> 00:40:34,760
Speaker 1: and gravity is strong enough to hold us together against

828
00:40:34,800 --> 00:40:38,279
Speaker 1: this like very weak breeze of dark energy. But then

829
00:40:38,320 --> 00:40:41,520
Speaker 1: at large distances, when gravity is weak, dark energy is

830
00:40:41,600 --> 00:40:44,080
Speaker 1: more powerful. It sort of adds up as you get

831
00:40:44,120 --> 00:40:47,400
Speaker 1: to these bigger distances, and so for the supercluster, it

832
00:40:47,480 --> 00:40:51,040
Speaker 1: really is an interesting question of whether that's the crossover point.

833
00:40:51,400 --> 00:40:54,480
Speaker 4: Yeah, it's interesting to think about. Like even here in

834
00:40:54,520 --> 00:40:57,080
Speaker 4: the room where I'm at and the room where you

835
00:40:57,160 --> 00:40:59,640
Speaker 4: are and where listeners are, if you just stare at

836
00:40:59,680 --> 00:41:02,759
Speaker 4: your hand, like the space that your hand is occupying

837
00:41:02,960 --> 00:41:07,040
Speaker 4: is expanding, it's getting trying to like pull your hand

838
00:41:07,080 --> 00:41:08,839
Speaker 4: apart in a way, except that your hand is being

839
00:41:08,920 --> 00:41:11,560
Speaker 4: held together by the bonds of the atoms in it.

840
00:41:11,600 --> 00:41:13,360
Speaker 4: But if it wasn't your hand, which is kind of

841
00:41:13,360 --> 00:41:14,640
Speaker 4: dissipate eventually, right.

842
00:41:14,600 --> 00:41:17,600
Speaker 1: Yeah, exactly, if there wasn't gravity and there weren't those forces,

843
00:41:17,640 --> 00:41:20,480
Speaker 1: then dark energy would pull your hand apart, and it

844
00:41:20,520 --> 00:41:22,640
Speaker 1: would pull the Earth from the Sun. So there's a

845
00:41:22,680 --> 00:41:25,359
Speaker 1: bunch of really interesting things all happening at the same time.

846
00:41:25,560 --> 00:41:29,879
Speaker 1: Like gravity needs time to form structure. You start from

847
00:41:29,880 --> 00:41:32,880
Speaker 1: like a fuzzy universe, and it gradually pulls things together,

848
00:41:33,360 --> 00:41:36,040
Speaker 1: and so as time goes on, gravity makes bigger and

849
00:41:36,040 --> 00:41:39,120
Speaker 1: bigger and bigger structures. So one reason we don't have

850
00:41:39,239 --> 00:41:43,680
Speaker 1: bigger structures than superclusters, or even if superclusters counter structure

851
00:41:43,840 --> 00:41:46,080
Speaker 1: is just time. Like without dark energy, if you ran

852
00:41:46,120 --> 00:41:48,960
Speaker 1: the universe forward, it would form larger and larger and

853
00:41:49,040 --> 00:41:52,080
Speaker 1: larger structures. But dark energy turned on a few billion

854
00:41:52,200 --> 00:41:55,440
Speaker 1: years ago and it started accelerating the expansion of the universe.

855
00:41:55,480 --> 00:41:58,760
Speaker 1: So gravity is sort of running out of time, which

856
00:41:58,760 --> 00:42:00,920
Speaker 1: means something kind of fascinating. It means that we are

857
00:42:01,000 --> 00:42:04,480
Speaker 1: living maybe at the moment of the largest structures in

858
00:42:04,520 --> 00:42:05,240
Speaker 1: the universe.

859
00:42:05,560 --> 00:42:07,560
Speaker 4: Well, I think that's kind of the point of discussion,

860
00:42:07,640 --> 00:42:10,799
Speaker 4: is like, is dark energy eventually going to tear our

861
00:42:10,880 --> 00:42:13,879
Speaker 4: supercluster apart? Or is maybe that expansion not strong enough

862
00:42:13,920 --> 00:42:16,759
Speaker 4: to really tear apart and keep things the way they

863
00:42:16,760 --> 00:42:19,839
Speaker 4: are forever, Right, that's kind of the question we're asking today.

864
00:42:19,920 --> 00:42:23,040
Speaker 1: Yeah, that's right. But whether or not our supercluster survives,

865
00:42:23,080 --> 00:42:26,640
Speaker 1: there will never be anything bigger in the universe because

866
00:42:26,719 --> 00:42:29,960
Speaker 1: dark energy is getting more and more powerful, and so

867
00:42:30,040 --> 00:42:33,560
Speaker 1: gravity will never have time to make anything bigger. Like

868
00:42:33,640 --> 00:42:36,680
Speaker 1: if a structure hasn't formed by now in the universe,

869
00:42:36,960 --> 00:42:40,640
Speaker 1: it will not because dark energy is just growing in power.

870
00:42:40,760 --> 00:42:44,600
Speaker 1: So whether or not our supercluster survives, nothing bigger than

871
00:42:44,640 --> 00:42:47,040
Speaker 1: anything that's been made already will ever be made.

872
00:42:47,280 --> 00:42:50,120
Speaker 4: Well, let's dig into that and what it might mean

873
00:42:50,200 --> 00:42:54,040
Speaker 4: for our local structure or superstructure of galaxies. Does that

874
00:42:54,120 --> 00:42:57,279
Speaker 4: reduce our chances of getting eaten by aliens? We'll see first,

875
00:42:57,320 --> 00:42:58,840
Speaker 4: let's take another quick break.

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00:43:02,920 --> 00:43:04,719
Speaker 1: When you pop a piece of cheese into your mouth

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00:43:12,120 --> 00:43:14,720
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Speaker 4: All right, we're talking about getting eaten by aliens, now, Daniel,

922
00:45:29,640 --> 00:45:31,600
Speaker 4: are you sort of prepared? It sounds like you look

923
00:45:31,640 --> 00:45:34,000
Speaker 4: forward to it. Are you preparing yourself? Are you staying

924
00:45:34,000 --> 00:45:38,040
Speaker 4: in shape or are you trying to fatten yourself like

925
00:45:38,040 --> 00:45:40,520
Speaker 4: like your goose, so that you're tastier to the aliens?

926
00:45:40,600 --> 00:45:42,240
Speaker 4: You know, tag on those calories.

927
00:45:43,120 --> 00:45:45,279
Speaker 1: I just don't even know, Like what do aliens like?

928
00:45:45,320 --> 00:45:48,360
Speaker 1: How am I supposed to anticipate what they're gonna find? Yummy?

929
00:45:48,560 --> 00:45:48,640
Speaker 4: Like?

930
00:45:49,000 --> 00:45:51,200
Speaker 1: So I'm just living my life, you know, and hoping

931
00:45:51,760 --> 00:45:52,600
Speaker 1: hoping that they.

932
00:45:56,400 --> 00:45:58,040
Speaker 4: I'm hoping they pick you two over me.

933
00:45:58,400 --> 00:46:00,480
Speaker 1: Hey, something we can agree on? Awesome?

934
00:46:00,600 --> 00:46:03,640
Speaker 4: Well, we're talking about whether we're actually talking about whether

935
00:46:03,960 --> 00:46:07,400
Speaker 4: our supercluster, which is called lanny Kia, which is a

936
00:46:07,480 --> 00:46:10,880
Speaker 4: cluster of galaxy clusters, will one day be torn apart

937
00:46:11,200 --> 00:46:14,600
Speaker 4: because of dark energy. Now, dark energy is expanding all

938
00:46:14,680 --> 00:46:18,000
Speaker 4: space as far as we know, and the question is

939
00:46:18,000 --> 00:46:21,160
Speaker 4: is it expanding space faster than lenny Kia can hold

940
00:46:21,200 --> 00:46:23,760
Speaker 4: itself together? And it sounds like you have the answer

941
00:46:23,760 --> 00:46:24,040
Speaker 4: to that.

942
00:46:24,239 --> 00:46:28,520
Speaker 1: I do. Yeah. So originally they defined a supercluster to

943
00:46:28,640 --> 00:46:31,160
Speaker 1: be this object because everything was sort of falling in

944
00:46:31,239 --> 00:46:34,719
Speaker 1: towards itself. That like delineated a blob of stuff that

945
00:46:34,800 --> 00:46:37,160
Speaker 1: was moving towards itself, and the next supercluster is a

946
00:46:37,160 --> 00:46:40,400
Speaker 1: blob that's moving towards itself. But then astronomers thought, hm,

947
00:46:40,520 --> 00:46:43,000
Speaker 1: that's not really enough. Like what we want is something

948
00:46:43,040 --> 00:46:45,560
Speaker 1: that's going to survive. We wanted to find a supercluster

949
00:46:45,600 --> 00:46:47,840
Speaker 1: to be something that is going to manage to hold

950
00:46:47,880 --> 00:46:50,680
Speaker 1: itself together against dark energy. So they did a bunch

951
00:46:50,719 --> 00:46:54,160
Speaker 1: of calculations and it looks like it's probably not gonna

952
00:46:54,200 --> 00:46:58,240
Speaker 1: make it. It looks like the supercluster is very loosely organized.

953
00:46:58,280 --> 00:47:01,080
Speaker 1: It's just more like a cloud or like a crowd,

954
00:47:01,239 --> 00:47:03,480
Speaker 1: you know, it happens to be nearby, but it's not

955
00:47:03,520 --> 00:47:06,080
Speaker 1: really like in equilibrium, you know, like the Earth and

956
00:47:06,120 --> 00:47:08,200
Speaker 1: the Sun had a lot of time to sort of

957
00:47:08,239 --> 00:47:10,880
Speaker 1: get in balance and find a place where they're happy together,

958
00:47:11,000 --> 00:47:13,680
Speaker 1: and the Earth can orbit forever and be here. But

959
00:47:13,719 --> 00:47:16,400
Speaker 1: the supercluster, like we said earlier, hasn't really had a

960
00:47:16,400 --> 00:47:20,160
Speaker 1: lot of time to gather together and to form something solid.

961
00:47:20,280 --> 00:47:22,520
Speaker 1: It's just sort of like a big blob of stuff

962
00:47:22,520 --> 00:47:24,880
Speaker 1: that happened to be near each other and are starting

963
00:47:24,880 --> 00:47:27,759
Speaker 1: to fall in a little bit. But dark energy is

964
00:47:27,800 --> 00:47:30,279
Speaker 1: powerful enough that they're pretty sure it's going to tear

965
00:47:30,320 --> 00:47:30,760
Speaker 1: it apart.

966
00:47:31,000 --> 00:47:32,959
Speaker 4: Now you mentioned one of the reasons is that dark

967
00:47:33,040 --> 00:47:36,920
Speaker 4: energy is getting stronger. Now, is it getting stronger at

968
00:47:36,920 --> 00:47:39,680
Speaker 4: the local level or is it just are you're saying

969
00:47:39,680 --> 00:47:42,440
Speaker 4: it's getting stronger because the universe is getting bigger and

970
00:47:42,480 --> 00:47:45,160
Speaker 4: so therefore there's more dark energy. Is it getting stronger

971
00:47:45,200 --> 00:47:47,840
Speaker 4: measureably like inside of my hand, Is this dark energy

972
00:47:47,920 --> 00:47:49,399
Speaker 4: that I would feel over the course of my life

973
00:47:49,480 --> 00:47:52,440
Speaker 4: getting stronger or is it going to be constant?

974
00:47:52,760 --> 00:47:55,799
Speaker 1: Dark energy is everywhere at the same level, so it's

975
00:47:55,840 --> 00:47:59,680
Speaker 1: a constant in space here and there and in other

976
00:47:59,719 --> 00:48:03,680
Speaker 1: gallon every chunk of space has the same amount of

977
00:48:03,800 --> 00:48:08,320
Speaker 1: dark energy. So when the universe expands, it's making more space,

978
00:48:08,480 --> 00:48:11,840
Speaker 1: which means more dark energy doesn't get diluted. It's a

979
00:48:12,000 --> 00:48:16,080
Speaker 1: constant in space. That's not true for other stuff like

980
00:48:16,200 --> 00:48:20,280
Speaker 1: matter or radiation. As the universe expands, matter gets more

981
00:48:20,320 --> 00:48:24,120
Speaker 1: dilute because more space doesn't mean more matter. So as

982
00:48:24,160 --> 00:48:26,879
Speaker 1: time goes on, the expansion of the universe means dark

983
00:48:27,040 --> 00:48:30,920
Speaker 1: energy is constant. But then it's an increasing fraction of

984
00:48:30,960 --> 00:48:34,239
Speaker 1: the energy of the universe because it doesn't get diluted

985
00:48:34,280 --> 00:48:37,200
Speaker 1: and other stuff does. And when dark energy is an

986
00:48:37,200 --> 00:48:41,239
Speaker 1: increasing fraction, that triggers more expansion, which only tills the

987
00:48:41,280 --> 00:48:45,200
Speaker 1: balance further towards dark energy. So it's like a runaway effect.

988
00:48:45,600 --> 00:48:48,720
Speaker 1: Once dark energy starts to win, which happened about six

989
00:48:48,840 --> 00:48:52,239
Speaker 1: billion years ago, it will zoom ahead and be impossible

990
00:48:52,239 --> 00:48:55,040
Speaker 1: to catch up to. But about seeing it change. We

991
00:48:55,160 --> 00:48:57,840
Speaker 1: live such short lives that we can't really notice it

992
00:48:57,960 --> 00:49:01,239
Speaker 1: changing on our time scales, but we can look back

993
00:49:01,320 --> 00:49:04,040
Speaker 1: into the past by looking out into deep space and

994
00:49:04,080 --> 00:49:06,759
Speaker 1: seeing how things used to be. And of course there's

995
00:49:06,800 --> 00:49:10,319
Speaker 1: a huge asterisk to all of this because we don't

996
00:49:10,320 --> 00:49:12,840
Speaker 1: really understand dark energy and what's going on and what

997
00:49:13,000 --> 00:49:15,680
Speaker 1: making this happen, and so the rules could be very

998
00:49:15,680 --> 00:49:18,760
Speaker 1: different from this very simple model that honestly we're pretty

999
00:49:18,760 --> 00:49:19,600
Speaker 1: sure is wrong.

1000
00:49:19,920 --> 00:49:21,799
Speaker 4: Right, Well, I guess what I mean is that, you know,

1001
00:49:21,880 --> 00:49:24,440
Speaker 4: we've always talked about dark energy as being kind of

1002
00:49:24,480 --> 00:49:28,120
Speaker 4: the force that's expanding the universe, expanding space, and I

1003
00:49:28,160 --> 00:49:30,400
Speaker 4: always think of it as sort of like the foot

1004
00:49:30,480 --> 00:49:33,600
Speaker 4: in the accelerator. So like when I'm driving, I press

1005
00:49:33,600 --> 00:49:36,320
Speaker 4: the accelerator and I usually leave it at a certain

1006
00:49:36,400 --> 00:49:39,520
Speaker 4: level to keep going at a certain speed. And if

1007
00:49:39,520 --> 00:49:41,720
Speaker 4: I want to accelerate go faster, I press it harder,

1008
00:49:42,040 --> 00:49:43,839
Speaker 4: and if I want to go slower, I let go

1009
00:49:43,920 --> 00:49:45,920
Speaker 4: of the pedal. And now it sort of seems from

1010
00:49:45,920 --> 00:49:49,040
Speaker 4: what I've we've talked about before that is that, you know,

1011
00:49:49,160 --> 00:49:52,759
Speaker 4: the pedal of dark energy is sort of pretty constant.

1012
00:49:52,960 --> 00:49:54,960
Speaker 4: And for example, our Solar system is never going to

1013
00:49:54,960 --> 00:49:58,280
Speaker 4: be torn apart by dark energy because the gravitational bonds

1014
00:49:58,280 --> 00:50:00,439
Speaker 4: between us and the Sun is strong enough. But even

1015
00:50:00,520 --> 00:50:03,360
Speaker 4: if the space between us gets bigger and bigger and bigger,

1016
00:50:03,400 --> 00:50:05,239
Speaker 4: we're always going to hang on to the Sun.

1017
00:50:05,560 --> 00:50:08,760
Speaker 1: Dark energy is expanding the space in our Solar system,

1018
00:50:08,840 --> 00:50:11,560
Speaker 1: but it doesn't have much effect over those short distances.

1019
00:50:11,600 --> 00:50:14,960
Speaker 1: And short distances is when gravity is the most powerful.

1020
00:50:15,320 --> 00:50:18,040
Speaker 1: So gravity is always going to be powerful enough to

1021
00:50:18,160 --> 00:50:21,239
Speaker 1: hold the Solar System together if dark energy is a

1022
00:50:21,360 --> 00:50:25,080
Speaker 1: constant in space. Remember, a constant in space can still

1023
00:50:25,120 --> 00:50:29,279
Speaker 1: be an increasing fraction of the universe's energy budget, which

1024
00:50:29,400 --> 00:50:33,440
Speaker 1: leads to accelerating expansion, even if the dark energy in

1025
00:50:33,520 --> 00:50:36,600
Speaker 1: any given chunk of space isn't changing except for the

1026
00:50:36,640 --> 00:50:39,680
Speaker 1: scenario of the Big Rip where dark energy gets more

1027
00:50:39,719 --> 00:50:42,319
Speaker 1: powerful and even tears our Solar system apart and even

1028
00:50:42,360 --> 00:50:45,040
Speaker 1: our atoms. But you're right, in our current projection of

1029
00:50:45,120 --> 00:50:47,799
Speaker 1: dark energy, it will not tear apart our Solar system.

1030
00:50:47,960 --> 00:50:51,960
Speaker 4: Right, and so it's because it's not being accelerated enough. Now,

1031
00:50:52,000 --> 00:50:54,960
Speaker 4: at the level of a galaxy, do we currently think

1032
00:50:55,000 --> 00:50:57,239
Speaker 4: that our galaxy is going to be torn apart or not?

1033
00:50:57,480 --> 00:50:59,880
Speaker 1: We think our galaxy is going to survive, and we

1034
00:51:00,120 --> 00:51:03,520
Speaker 1: think our group is going to survive. So everything below

1035
00:51:03,560 --> 00:51:06,920
Speaker 1: a supercluster, we're pretty sure gravity is already won and

1036
00:51:07,000 --> 00:51:10,000
Speaker 1: it's going to continue to win again. Assuming this naive

1037
00:51:10,080 --> 00:51:14,120
Speaker 1: projection of dark energy continuing at the same rate that

1038
00:51:14,160 --> 00:51:16,160
Speaker 1: it's been continuing, that it's not going to ramp up

1039
00:51:16,200 --> 00:51:18,960
Speaker 1: into the big rip or turn around into the big crunch.

1040
00:51:19,440 --> 00:51:22,160
Speaker 1: So our solar system will survive. Our galaxy will survive,

1041
00:51:22,200 --> 00:51:26,040
Speaker 1: our local group will survive. The Virgo cluster nearby will survive.

1042
00:51:26,239 --> 00:51:30,160
Speaker 1: But the question is will our supercluster survive. And that's

1043
00:51:30,200 --> 00:51:33,399
Speaker 1: where dark energy starts to win. Dark energy will tear

1044
00:51:33,680 --> 00:51:37,160
Speaker 1: these groups of galaxies apart and basically pull apart.

1045
00:51:37,000 --> 00:51:40,560
Speaker 4: Lenika because the things that make up Lenikaia, you know,

1046
00:51:40,800 --> 00:51:44,520
Speaker 4: our cluster, the Virgo cluster, the great attractor. They are

1047
00:51:44,760 --> 00:51:48,600
Speaker 4: being attracted to each other, but not more than the

1048
00:51:48,800 --> 00:51:51,520
Speaker 4: expansion of the huge amount of space in between them.

1049
00:51:51,560 --> 00:51:52,480
Speaker 4: That's kind of what you're saying.

1050
00:51:52,600 --> 00:51:55,879
Speaker 1: Yeah, it's just too big, right. Gravity gets weak over

1051
00:51:55,920 --> 00:51:58,759
Speaker 1: those huge distances. It does not have the strength to

1052
00:51:58,840 --> 00:52:02,160
Speaker 1: overcome dark energy. And as the distances get bigger, dark

1053
00:52:02,280 --> 00:52:05,480
Speaker 1: energy becomes harder and harder to surmount. Like it doesn't

1054
00:52:05,480 --> 00:52:08,400
Speaker 1: take that much mass and that much gravity to overcome

1055
00:52:08,520 --> 00:52:11,200
Speaker 1: dark energy in our solar system. It takes more mass

1056
00:52:11,200 --> 00:52:13,759
Speaker 1: to overcome the dark energy in the galaxy, and even

1057
00:52:13,840 --> 00:52:16,360
Speaker 1: more to overcome the dark energy of the group. But

1058
00:52:16,440 --> 00:52:19,400
Speaker 1: to overcome the dark energy of the supercluster, we need

1059
00:52:19,400 --> 00:52:22,760
Speaker 1: an incredible amount of mass because of the vast distances involved.

1060
00:52:23,360 --> 00:52:26,160
Speaker 4: So you're saying that lanni Kia the supercluster of galaxies,

1061
00:52:26,440 --> 00:52:29,480
Speaker 4: It's really more like a visual cluster, right, It's more

1062
00:52:29,520 --> 00:52:31,840
Speaker 4: of a visual structure. It looks like it's sort of

1063
00:52:31,840 --> 00:52:34,239
Speaker 4: holding together. It looks like a wisp of cloud or

1064
00:52:34,239 --> 00:52:37,000
Speaker 4: a crowd of people in the park, but really there's

1065
00:52:37,040 --> 00:52:41,120
Speaker 4: nothing that much holding it together, or at least proportionally

1066
00:52:41,200 --> 00:52:43,040
Speaker 4: to the dark energy in the universe.

1067
00:52:43,120 --> 00:52:46,240
Speaker 1: Yeah, our supercluster seems to be right about that turnover

1068
00:52:46,320 --> 00:52:49,359
Speaker 1: point where things that are smaller or more massive either

1069
00:52:49,400 --> 00:52:52,680
Speaker 1: one would survive and things that are bigger definitely would not.

1070
00:52:53,400 --> 00:52:55,600
Speaker 1: So sort of fascinating. It's like the biggest kind of

1071
00:52:55,600 --> 00:52:58,480
Speaker 1: blog we can identify. But it's not really technically a structure.

1072
00:52:58,520 --> 00:53:00,560
Speaker 1: So there were some papers a few years ago suggesting

1073
00:53:00,760 --> 00:53:03,839
Speaker 1: we shouldn't be calling leni Ka a supercluster because it's

1074
00:53:03,840 --> 00:53:06,879
Speaker 1: not a structure, and they said, maybe we should redefine

1075
00:53:07,000 --> 00:53:10,759
Speaker 1: what a structure is as something that will survive in

1076
00:53:10,800 --> 00:53:14,400
Speaker 1: the future, right, things that will hold themselves together in

1077
00:53:14,480 --> 00:53:18,040
Speaker 1: the long term after dark energy has played itself out.

1078
00:53:18,400 --> 00:53:21,840
Speaker 1: So by that definition, the lani Ka supercluster is not

1079
00:53:22,120 --> 00:53:24,480
Speaker 1: actually a structure, and we shouldn't even be calling it

1080
00:53:24,520 --> 00:53:25,279
Speaker 1: a supercluster.

1081
00:53:25,560 --> 00:53:28,000
Speaker 4: Well, I mean, as long as you're playing with definitions,

1082
00:53:28,000 --> 00:53:30,480
Speaker 4: you can get either way. I feel like, right, like

1083
00:53:30,520 --> 00:53:33,840
Speaker 4: you could just redefine what a super cluster means. A

1084
00:53:33,880 --> 00:53:36,760
Speaker 4: supercluster could just mean like a cloud or a crowd

1085
00:53:36,800 --> 00:53:39,160
Speaker 4: in a park. Right, Maybe you could just define a

1086
00:53:39,160 --> 00:53:43,680
Speaker 4: supercluster as not necessarily a structure, but you can still

1087
00:53:43,680 --> 00:53:46,400
Speaker 4: call it a super cluster, right because a cluster, the

1088
00:53:46,400 --> 00:53:48,560
Speaker 4: word cluster just means like, hey, hanging out together.

1089
00:53:48,680 --> 00:53:50,560
Speaker 1: Mm hmm, I suppose. I mean, you could call it

1090
00:53:50,560 --> 00:53:53,120
Speaker 1: a banana if you wanted. Yeah, we want these words

1091
00:53:53,160 --> 00:53:56,120
Speaker 1: to have some meaning to them, and so these papers

1092
00:53:56,120 --> 00:53:58,839
Speaker 1: suggest that we shouldn't. And they actually suggest another name

1093
00:53:58,920 --> 00:54:02,239
Speaker 1: because there are some other superclusters that they do think

1094
00:54:02,360 --> 00:54:06,120
Speaker 1: will hold themselves together. So some superclusters are more massive

1095
00:54:06,360 --> 00:54:08,759
Speaker 1: or a little bit closer together, and they think they

1096
00:54:08,800 --> 00:54:12,280
Speaker 1: will overcome dark energy, and they suggest calling these things

1097
00:54:12,680 --> 00:54:16,879
Speaker 1: superstise clusters. What it's a word in Latin that means

1098
00:54:17,000 --> 00:54:20,160
Speaker 1: survivor probably not pronouncing it correctly, but I think it's

1099
00:54:20,200 --> 00:54:24,640
Speaker 1: supersts clusters. It's the new name for superclusters that will

1100
00:54:24,719 --> 00:54:28,799
Speaker 1: survive dark energy.

1101
00:54:29,000 --> 00:54:32,360
Speaker 4: It sounds like we're really rather about way for what

1102
00:54:32,480 --> 00:54:34,440
Speaker 4: did you say, what did you just call them structures

1103
00:54:34,480 --> 00:54:37,560
Speaker 4: like superstructures? Why do we have to go Latin?

1104
00:54:37,960 --> 00:54:40,719
Speaker 1: Well, because you know, not all superclusters are structures. They

1105
00:54:40,719 --> 00:54:43,080
Speaker 1: don't hold themselves together. And you're right, we could just

1106
00:54:43,120 --> 00:54:45,719
Speaker 1: put a name on things. But we like this hierarchy

1107
00:54:45,760 --> 00:54:47,919
Speaker 1: of structures. We like thinking about the universe in terms

1108
00:54:47,960 --> 00:54:50,400
Speaker 1: of the structures all the way down from the proton

1109
00:54:50,560 --> 00:54:53,680
Speaker 1: zooming out to the biggest structures in the universe. And

1110
00:54:53,719 --> 00:54:56,720
Speaker 1: we want a consistency there. We want it to mean something.

1111
00:54:56,760 --> 00:54:58,799
Speaker 1: For there to be a structure you don't want just

1112
00:54:58,840 --> 00:55:00,960
Speaker 1: like an arbitrary definition at every level.

1113
00:55:01,080 --> 00:55:03,920
Speaker 4: Well, I feel like maybe you're only having to adjust

1114
00:55:03,960 --> 00:55:07,480
Speaker 4: this definition because of dark energy, right, Like, if it

1115
00:55:07,520 --> 00:55:10,239
Speaker 4: wasn't for dark energy, Yeah, Lenny, care would be a

1116
00:55:10,239 --> 00:55:12,600
Speaker 4: structure and it would be gravitational bound and it would

1117
00:55:12,640 --> 00:55:15,120
Speaker 4: last until the end of time. But you have dark energy,

1118
00:55:15,160 --> 00:55:18,800
Speaker 4: which will make it fuzzy up in the future, except

1119
00:55:18,840 --> 00:55:21,440
Speaker 4: that you don't know what dark energy is going to do, right,

1120
00:55:21,719 --> 00:55:24,880
Speaker 4: So it seems a little bit like you're rushing ahead

1121
00:55:24,920 --> 00:55:27,279
Speaker 4: to redefine everything based on something you don't know what's

1122
00:55:27,280 --> 00:55:27,759
Speaker 4: going to happen.

1123
00:55:28,440 --> 00:55:31,839
Speaker 1: Well, you know, astronomers love fights over names and definitions

1124
00:55:31,840 --> 00:55:34,279
Speaker 1: and who gets to name something, so this is one

1125
00:55:34,280 --> 00:55:36,080
Speaker 1: of the hot topics these days. But you're right that

1126
00:55:36,120 --> 00:55:38,560
Speaker 1: the definition of depends a little bit on what happens

1127
00:55:38,600 --> 00:55:41,200
Speaker 1: in the future. In that sense, it's sort of like

1128
00:55:41,280 --> 00:55:43,200
Speaker 1: the way you think about an event horizon for a

1129
00:55:43,239 --> 00:55:46,600
Speaker 1: black hole, Like the event horizon isn't a physical structure.

1130
00:55:46,719 --> 00:55:49,800
Speaker 1: It's just like a delineation that says anything passed here

1131
00:55:49,960 --> 00:55:53,120
Speaker 1: in the infinite future will never escape. To really know that,

1132
00:55:53,160 --> 00:55:55,799
Speaker 1: you have to see the infinite future, we just sort

1133
00:55:55,800 --> 00:55:58,160
Speaker 1: of project it and in the same way we like

1134
00:55:58,400 --> 00:56:00,319
Speaker 1: group this stuff together and say, hey, is this going

1135
00:56:00,360 --> 00:56:02,600
Speaker 1: to survive? Is so that we can call it a

1136
00:56:02,600 --> 00:56:06,040
Speaker 1: cluster or a structure or a supercluster or a superstise

1137
00:56:06,200 --> 00:56:10,040
Speaker 1: cluster or whatever the astronomers finally settle on. But the

1138
00:56:10,120 --> 00:56:13,560
Speaker 1: basic story is that if dark energy continues the way

1139
00:56:13,600 --> 00:56:17,239
Speaker 1: it has been, probably lani Kea will just dissolve into

1140
00:56:17,239 --> 00:56:18,960
Speaker 1: a bunch of islands of mass.

1141
00:56:19,080 --> 00:56:21,680
Speaker 4: It sounds more like you're saying that we shouldn't call

1142
00:56:21,719 --> 00:56:23,279
Speaker 4: anything anything until the end of time.

1143
00:56:24,239 --> 00:56:26,840
Speaker 1: Go that's exactly right. We want to be totally accurate

1144
00:56:26,840 --> 00:56:28,480
Speaker 1: about everything. We've got to wait to the end of

1145
00:56:28,520 --> 00:56:31,200
Speaker 1: the universe. Then we'll know what was going on.

1146
00:56:31,640 --> 00:56:33,560
Speaker 4: Well, let's spend a minute here because if we still

1147
00:56:33,560 --> 00:56:36,080
Speaker 4: have like a few minutes left here talking about the

1148
00:56:36,200 --> 00:56:38,040
Speaker 4: dark energy, right, because it seems like it all depends

1149
00:56:38,080 --> 00:56:40,520
Speaker 4: on what dark energy is going to do, whether the

1150
00:56:40,600 --> 00:56:43,160
Speaker 4: universe is going to press harder on the accelerator or

1151
00:56:43,239 --> 00:56:46,239
Speaker 4: press lower on the accelerator. What's been the history of that,

1152
00:56:46,360 --> 00:56:48,960
Speaker 4: Like since the beginning of the universe, there was a

1153
00:56:49,040 --> 00:56:51,480
Speaker 4: huge expansion and then it slowed down and now it's

1154
00:56:51,480 --> 00:56:52,319
Speaker 4: picking back up again.

1155
00:56:52,400 --> 00:56:54,279
Speaker 1: Right, Yeah, that's true. And there's sort of a bunch

1156
00:56:54,280 --> 00:56:56,879
Speaker 1: of different time periods to talk about there, Like there

1157
00:56:56,920 --> 00:57:00,600
Speaker 1: was inflation very very early on, huge expansion very short

1158
00:57:00,640 --> 00:57:03,480
Speaker 1: time scales. We don't understand what caused that at all.

1159
00:57:03,560 --> 00:57:06,319
Speaker 1: There's a few theories insuloton field, whatever, but it's a

1160
00:57:06,320 --> 00:57:08,960
Speaker 1: big question mark. And then after that, you know what

1161
00:57:09,000 --> 00:57:10,919
Speaker 1: we call the Big Bang, the sort of like more

1162
00:57:10,960 --> 00:57:15,120
Speaker 1: gradual expansion of the universe as it cools. We have

1163
00:57:15,280 --> 00:57:18,520
Speaker 1: pretty good models of that. We have gravity, and we

1164
00:57:18,560 --> 00:57:20,760
Speaker 1: have dark energy, and we have all the other forces

1165
00:57:20,760 --> 00:57:23,480
Speaker 1: that come into play, and in that period, we can

1166
00:57:23,520 --> 00:57:26,560
Speaker 1: model dark energy as constant, saying like a chunk of

1167
00:57:26,560 --> 00:57:29,160
Speaker 1: space has the same amount of potential energy, and that

1168
00:57:29,240 --> 00:57:33,120
Speaker 1: creates this repulsive field in general relativity, which drives the

1169
00:57:33,160 --> 00:57:36,320
Speaker 1: expansion of the universe. Remember that dark energy can be

1170
00:57:36,400 --> 00:57:39,440
Speaker 1: a constant in space, every chunk has the same amount,

1171
00:57:39,640 --> 00:57:43,280
Speaker 1: but still be a growing fraction of the universe's energy

1172
00:57:43,400 --> 00:57:46,960
Speaker 1: because other stuff is getting diluted as things expand. So

1173
00:57:47,080 --> 00:57:50,960
Speaker 1: dark energy is both constant and taking over as other

1174
00:57:51,040 --> 00:57:54,960
Speaker 1: things get more dilute. It's not exactly true, because we

1175
00:57:55,080 --> 00:57:58,040
Speaker 1: make these measurements over time we get slightly different answers,

1176
00:57:58,480 --> 00:58:00,840
Speaker 1: so nobody really knows if that's true or it needs

1177
00:58:00,840 --> 00:58:02,800
Speaker 1: a little bit of adjusting. We had a whole episode

1178
00:58:02,800 --> 00:58:06,160
Speaker 1: about early dark energy, whether dark energy was more powerful

1179
00:58:06,160 --> 00:58:08,920
Speaker 1: early on this kind of stuff. But mostly we can

1180
00:58:09,000 --> 00:58:12,800
Speaker 1: explain the history of the universe after that first inflationary period.

1181
00:58:12,960 --> 00:58:16,200
Speaker 1: We can explain it assuming dark energy is constant. So

1182
00:58:16,240 --> 00:58:18,560
Speaker 1: that seems to be a reasonable assumption.

1183
00:58:18,280 --> 00:58:20,920
Speaker 4: Meaning that the universe is not pressing the accelerator faster,

1184
00:58:21,280 --> 00:58:22,520
Speaker 4: it's just kind of leaving it on.

1185
00:58:22,880 --> 00:58:25,640
Speaker 1: That's right, it's pressing the accelerator at the same level,

1186
00:58:25,920 --> 00:58:28,240
Speaker 1: meaning every part of space has the same amount of

1187
00:58:28,320 --> 00:58:31,720
Speaker 1: dark energy. But eventually that does take over. You know,

1188
00:58:31,720 --> 00:58:34,120
Speaker 1: like when you press the accelerator on your car. There

1189
00:58:34,160 --> 00:58:37,160
Speaker 1: are other things keeping you from going faster and faster, right,

1190
00:58:37,240 --> 00:58:40,160
Speaker 1: there's friction and this error resistance whatever. That doesn't quite

1191
00:58:40,200 --> 00:58:42,439
Speaker 1: apply to this model, because in this model, the level

1192
00:58:42,480 --> 00:58:45,080
Speaker 1: that the accelerator is at ends up speeding us up.

1193
00:58:45,120 --> 00:58:48,200
Speaker 1: It's like winning against the other forces. So it really

1194
00:58:48,400 --> 00:58:51,520
Speaker 1: is accelerating the expansion of the universe. So sort of

1195
00:58:51,560 --> 00:58:54,000
Speaker 1: two different ideas there. One is the amount of dark

1196
00:58:54,120 --> 00:58:57,920
Speaker 1: energy in space is constant, but because it overcomes the

1197
00:58:57,960 --> 00:59:02,400
Speaker 1: other things, it ends up accelerating the expansion of the universe.

1198
00:59:02,440 --> 00:59:06,560
Speaker 4: Meaning that the space is growing at an accelerated rate.

1199
00:59:06,680 --> 00:59:10,120
Speaker 4: But is that acceleration getting faster or is it slowing

1200
00:59:10,160 --> 00:59:11,920
Speaker 4: down or is it pretty constant.

1201
00:59:12,080 --> 00:59:15,400
Speaker 1: We think that acceleration itself is pretty constant, yes, And

1202
00:59:15,440 --> 00:59:17,360
Speaker 1: we can track that back through the history of the

1203
00:59:17,440 --> 00:59:19,720
Speaker 1: universe and see if that explains our history, and it

1204
00:59:19,800 --> 00:59:22,760
Speaker 1: mostly does. Again, there's some questions there about the early

1205
00:59:22,800 --> 00:59:25,600
Speaker 1: first few bits you might have read about, like different

1206
00:59:25,640 --> 00:59:28,840
Speaker 1: measurements of the Hubble constant that we can't quite reconcile.

1207
00:59:28,920 --> 00:59:30,960
Speaker 1: And that's what that's about. Is that level of acceleration

1208
00:59:31,080 --> 00:59:33,960
Speaker 1: the same all the way through time or not It

1209
00:59:34,040 --> 00:59:35,760
Speaker 1: is it or not? We think that it is, but

1210
00:59:35,840 --> 00:59:38,240
Speaker 1: we don't quite know that these measurements that we can't

1211
00:59:38,280 --> 00:59:39,080
Speaker 1: quite reconcile.

1212
00:59:39,760 --> 00:59:41,640
Speaker 4: I guess it's kind of the difference of whether dark

1213
00:59:41,760 --> 00:59:45,000
Speaker 4: energy is a constant like a number in your equations

1214
00:59:45,000 --> 00:59:47,360
Speaker 4: of the universe, or is it a variable that somehow

1215
00:59:47,480 --> 00:59:50,400
Speaker 4: feeds in it itself or that maybe has a little

1216
00:59:50,440 --> 00:59:53,240
Speaker 4: button that you know, the makers of the universe are

1217
00:59:54,400 --> 00:59:55,640
Speaker 4: increasing exactly.

1218
00:59:55,680 --> 00:59:58,160
Speaker 1: Yeah, right now, we can describe it just using a number.

1219
00:59:58,400 --> 01:00:01,320
Speaker 1: It's a cosmological constant. We don't know where that number

1220
01:00:01,320 --> 01:00:03,200
Speaker 1: comes from or why it is what it is. We

1221
01:00:03,240 --> 01:00:05,560
Speaker 1: have really no explanation for it. But we can mostly

1222
01:00:05,600 --> 01:00:08,160
Speaker 1: describe the history of the universe using just a number

1223
01:00:08,360 --> 01:00:09,280
Speaker 1: for dark energy.

1224
01:00:09,520 --> 01:00:11,360
Speaker 4: All right, Well, it sounds like the answer to the

1225
01:00:11,440 --> 01:00:14,800
Speaker 4: question of the episode is yes. It sounds like, as

1226
01:00:14,840 --> 01:00:16,920
Speaker 4: far as we know, if things stay the same with

1227
01:00:17,040 --> 01:00:20,760
Speaker 4: dark energy, our super cluster of galaxies that we live

1228
01:00:20,800 --> 01:00:24,120
Speaker 4: in will be torn apart sometime in the future.

1229
01:00:24,360 --> 01:00:27,880
Speaker 1: That's right, So our more immedia cosmic neighborhood is safe

1230
01:00:27,920 --> 01:00:31,439
Speaker 1: and probably will eventually collapse into a black hole. But

1231
01:00:31,480 --> 01:00:34,480
Speaker 1: the Virgo cluster will not be in our neighborhood forever.

1232
01:00:35,080 --> 01:00:38,000
Speaker 1: Dark energy will take over and pull us apart from it.

1233
01:00:38,000 --> 01:00:41,080
Speaker 4: It's going to be declustered, but we won't know, I

1234
01:00:41,120 --> 01:00:42,320
Speaker 4: guess until the end of time.

1235
01:00:42,520 --> 01:00:45,200
Speaker 1: That's right, So we'll do our five millionth episode at

1236
01:00:45,240 --> 01:00:47,680
Speaker 1: the end of time and we'll answer this question definitively.

1237
01:00:48,200 --> 01:00:51,320
Speaker 4: So maybe I shouldn't call you a person, Daniel, because eventually,

1238
01:00:51,320 --> 01:00:53,600
Speaker 4: who knows, maybe aliens will come and tear you apart.

1239
01:00:54,120 --> 01:00:55,800
Speaker 4: We just have to wait and see before we call

1240
01:00:55,840 --> 01:00:56,320
Speaker 4: you a person.

1241
01:00:56,520 --> 01:00:58,360
Speaker 1: That's true. From that point of view. None of us are.

1242
01:00:58,320 --> 01:01:03,600
Speaker 4: Structured, So I'll be lunch in our future, Hey, fellow, lunch.

1243
01:01:03,960 --> 01:01:06,880
Speaker 1: Meat ashes to ashes, dust to lunch.

1244
01:01:06,840 --> 01:01:12,120
Speaker 4: And lunch to something else. Once the eighties digestus, all right, Well,

1245
01:01:12,480 --> 01:01:16,920
Speaker 4: pretty interesting lesson to think about, not just like our

1246
01:01:16,960 --> 01:01:19,680
Speaker 4: place in the universe and how small we are compared

1247
01:01:19,720 --> 01:01:23,440
Speaker 4: to these enormous clusters of galaxies, but also about the

1248
01:01:23,480 --> 01:01:26,919
Speaker 4: permanence of the universe, like even something as huge as

1249
01:01:26,920 --> 01:01:29,480
Speaker 4: a super cluster Lenny Kia, it may not be around

1250
01:01:29,480 --> 01:01:31,080
Speaker 4: for the entire life of the universe.

1251
01:01:31,160 --> 01:01:34,960
Speaker 1: That's right, and think about these incredibly powerful, vast forces

1252
01:01:35,000 --> 01:01:39,440
Speaker 1: at play, tugging on these galaxies with millions and billions

1253
01:01:39,440 --> 01:01:42,800
Speaker 1: of stars, all in a battle against dark energy. It's

1254
01:01:42,840 --> 01:01:45,200
Speaker 1: really a very dynamical place if you think about the

1255
01:01:45,280 --> 01:01:48,640
Speaker 1: universe and sort of fast forward. It's slashing, it's frothing,

1256
01:01:48,960 --> 01:01:49,959
Speaker 1: it's doing a lot.

1257
01:01:50,280 --> 01:01:52,720
Speaker 4: All right. We hope you enjoyed that. Thanks for joining us,

1258
01:01:53,760 --> 01:01:54,520
Speaker 4: See you next time.

1259
01:02:02,360 --> 01:02:05,160
Speaker 1: Thanks for listening, and remember that. Daniel and Jorge Explain

1260
01:02:05,200 --> 01:02:09,160
Speaker 1: the Universe is a production of iHeartRadio. For more podcasts

1261
01:02:09,200 --> 01:02:13,880
Speaker 1: from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever

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