StarTalk Radio - Cosmic Queries – Edge of the Universe

Episode Date: December 6, 2019

What lies beyond the edge of the universe? Neil deGrasse Tyson, comic co-host Chuck Nice, and astrophysicist Janna Levin, PhD, answer your fan-submitted Cosmic Queries about higher dimensions, the multiverse, the Big Bang, and much, much more!NOTE: StarTalk+ Patrons and All-Access subscribers can watch or listen to this entire episode commercial-free here: https://www.startalkradio.net/show/cosmic-queries-edge-of-the-universe/Thanks to this week’s Patrons for supporting us: Paul Love, Sharon Coates, Jon Duey, Roy Hill-Percival, Jose Clark, Dr. Janet L. Walsh.Photo Credit: Image Credit: X-ray: NASA/CXC/SAO/G.Schellenberger et al.; Optical: SDSS. Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

From the American Museum of Natural History in New York City, and beaming out across all of space and time, this is StarTalk, where science and pop culture collide. This is StarTalk. I'm your host, Neil deGrasse Tyson, your personal astrophysicist. Today we're doing Cosmic Queries. Topic, the edge of space-time. The edge of the universe. Chuck. Hey, Neil. You're going to join me there. I am. But we can't do it alone. I'm going to join you in that shirt. You know, you know, whether you're watching or listening, that I wear cosmically colorful clothing. Yes. But my shirt I'm wearing today

is particularly cosmically colorful. Yes. It's in your face. It's smack down. It's... Well, you're going to have to go to Patreon

or maybe we'll take a picture of it and you'll have to see it on our website or maybe you'll see it on YouTube, but you got to see this shirt. Seriously.

It's some pretty lovely celestial bodies going on there. We have Jan Eleven to help us. Yay! Jan, professor of physics, Barnard College, Columbia University. Welcome back. I love being here.

We needed you for this topic. Because my knowledge of cosmology is little, and yours is big. Not as big as the universe. As the universe itself. Okay. All right. So anytime we do a Cosmic Queries, we bring it. I love it. We bring in the universe itself. Okay. All right. So anytime we do a Cosmic Queries, we bring her in.

I love it. We bring in the big guns. This is Antenna is the big guns, man. Right, right. Good stuff. So what do you have? So we got Cosmic Queries as we glean from all over the internet.

And of course, we always start with a Patreon patron because these people... Just a quick sec. So your book, Black Hole Blues, that's still out there. It's still out there. Okay, Chuck, we got to your book, Black Hole Blues, that's still out there. It's still out there. Okay, Chuck, we got to do it.

Black Hole Blues. I've got to learn a harmony to that. I can be like over here. There's got to be a way when someone picks up the book, it says, Black Hole Blues. Guaranteed more sales. What if it's just every time you walk past it on the shelf? Oh, you just heard it.

Yeah, that'd be so cool. It's an eighth. We've got to put it on the shelf right right here. With a little riff behind it. Black hole blues. So that was about the discovery of gravitational waves.

Yeah, so. Moving through the universe. Yeah, exactly. So right before that succeeded, in the 50 years it took them to succeed. Before we successfully measured it. Yeah. Ray Weiss, who's one of the original architects,

just was shaking his head and saying, you know, we don't detect black holes. This thing is a failure. So like the title was just kind of like, it's the black hole blues. Sweet. But then he detected it.

So he got a new title? Yeah. The new title is called Nobel Prize Winner. Black hole Nobel Prize. The Nobel Prize Jig. He said all the way to the bank on that one. Nice.

All right. So good to hear you're still out there. Yes. Thank you for that. Let's start off with a Patreon patron. This is Chris Hampton who supports us on Patreon who wants to know this. Could it be that the universe that we are in is actually finite? Could it be that the universe that we are in is actually finite?

However, the universal structure is infinite via size and relativity, meaning the universal structure gets infinitely smaller and vice versa, kind of like infinitely dividing in half. I imagine it would look something like a very complex fractal. He's going a lot of places. Wow. All right, Jen, take that however you want to do that. He's going a lot of places. Wow. All right, Jen, take that however you want. I'm going to write. And I have a question for Chris first.

Is it sativa or endica? Sativa? Endica. Okay. Which is the one that he would have fallen asleep before making it to the end of the tweet? I love the sativa. I think that's, I don't know. Is that the end?

I don't know. Okay, well, we just all revealed our, like. When I actually used that substance, it was called weed. They didn't put any other name on it. Like, if you went to your. Easy to pronounce and remember. Right, that was it. Right.

If you went to your dealer and you went, so now is this sativa or indica? He'd be like, man, what's wrong with you? Smoke it. Get the hell out of my house. Go smoke that and get out. Perfect. Anyway, so you want to take a shot at this? I'm into this.

I'm into this. Okay. So my first book is about whether or not the universe is infinite or finite. It's a question we don't know the answer to yet. And the title of that book? How the universe got its spots. I remember that, yeah. So How the Universe Got Its Spots is about could we tell the shape and size of the universe by looking in the hot and cold spots in the Big Bang, in the light

left over from the Big Bang. But the question, let's just take it really theoretically. We absolutely do not know that the universe is infinite. And it may well be that it's finite the way the earth is finite. That, you know, we leave New York City, we travel in a straight line. Maybe we'd have to swim a little, get on a boat, but you travel in a straight line, you're going to come back to New York City again. And so it could be that we... But you can travel forever.

I was going to say, it's infinite in where you can travel. It's infinite in you don't get to an edge. Right. You never get to an edge, which is beautiful. So exactly the same thing with the universe. You're not going to sail off the edge of the earth, right? Like, you know, Spanish explorers waved goodbye and wondered, right, if they'd just go off the side. But no, we know that's not what happens.

And so similarly, we could leave the Milky Way galaxy. We could watch it recede behind us. We could travel in as straight a line as possible and find ourselves coming back to the Milky Way again. Wow. And it's so Planet of the Apes, right? It's like,

Damn you! Yay! You finally did it. Damn you all to hell. Oh, that'd be great. So great. So my interpretation of that was that

they went all the way around. Yeah. And so the interesting thing is that also means that if you look at distant galaxies, the light is also traveling all the way around the universe. is that also means that if you look at distant galaxies, the light is also traveling all the way around the universe. So it could be that some of those distant galaxies are the Milky Way,

and we're seeing the light from the Milky Way wrap all the way around and come back to us. We'd be seeing the Milky Way in the past. Wow. So it would be hard to know. Like maybe we'd see an active black hole quasar with jets flying out in the early phases of the Milky Way, and we'd think, oh, that's just a different galaxy. Wow!

Young galaxies look very different from mature galaxies. And we used to think that there were different kinds of objects in the outer universe, like quasars. Why are they all distant? How come there's not a quasar right next door with these monstrous nuclear emissions? And we had to figure out

that it's likely just younger galaxies, and maybe we used to look like a quasar, and we don't anymore. Right. So even a distant galaxy looking back at us is seeing us in the past, given the light travel time, so we could still look like a quasar

to a distant galaxy. Wow. Like, I have this huge active galactic nucleus. Because they're not seeing us as we are now. No, they're not. They're seeing us as we were. Billions of years ago. Wow.

Yeah. Oh, my God. So that's the beauty. We get to see in the past. I need someone that's the T-Bone right now. Wow. Well, and then it gets more because there are reasons

that people start to suspect that there are extra spatial dimensions and that they are not only finite, but really technically really small. Like that journey

to go all the way around them is something that would happen incredibly quickly and it's too small for us to like literally stick our hands

in that direction in some sense. So we're looking everywhere. Those extra dimensions are everywhere, but we can't actually notice them. Wow. What does it mean for a dimension to be smaller than another dimension?

What does that even mean? So think of, like, a straw is a good example where it's a two-dimensional surface. You know what the first straws were made of? I'm going to go with flax. No? Yeah, straw, straw. Thank you. Thank you for getting that. No. Yeah, straw. Straw, yeah. Thank you.

Thank you for getting that. I knew I could make that joke to him. I knew it. Oh, God. All right, go ahead. The only reason I would, it's because flax and hair. Oh, yeah? Yeah, that's the only reason why I would have the connection between flax and straw.

Yeah, flax and hair. So a straw is small in one direction on the surface, right? If you think there's a direction in which it's totally wrapped up and small. So a straw is small in one direction on the surface, right? If you think there's a direction in which it's totally wrapped up and small. And then there's a long direction. So straws are mostly long. They're mostly long. And you could glue the top end of the bottom end of a straw to make that long direction also finite.

So then you'd just travel around the world. It could be really big. It could be, you know, a mile around, but still be connected. But it's only a few millimeters around in this direction. In this other dimension. So literally the length of traveling before you come back to where you started is smaller. So most of how you use a straw does not access that other dimension. It's really the length because you're trying to get the liquid from here to here.

Yeah. And so most of your, you're using the long dimension of the straw. Yeah. So, in, we, then the question we start to ask is, what if the universe is a kind of space-time origami, when it's created in the Big Bang, that all the dimensions are wrapped up, and maybe in very complicated ways, like the dimension of the straw being wrapped up, but one dimension just gets very, very big, or in our case, three. Three with three big dimensions. We have three big dimensions.

We have time, which is a fourth. So we know there's up, down, north, south, east, west. That's it. You specify those things and you definitely know where you are in space. You specify time and we can actually meet. Right, here we are. But those extra directions just maybe didn't ever expand.

And so one of the things things even that I'll work on and string theorists will work on people is why would only three dimensions get large if those other dimensions exist? Interesting. So it could be that we'll understand the large connectedness, finite nature of space by looking in really high-energy accelerator experiments.

Because people have asked at the Large Hadron Collider, could you perceive these extra dimensions if they exist? Okay. Wow, that I got to tell you. Okay. Chris? We're done with the show. Okay, and people will be back next week. We're just going to let you think, and people, we'll be back next week.

We're just going to let you think about that. It's a week's worth of mind-blowing. That is. That is a big start. That was a big start. To Cosmic Queries. Wow, man. That's fascinating stuff.

Just fascinating. All right, let's move on to Paul Love, who says, given that... Is that because you can pronounce his name? That's why we're going to him next? Let me tell you something. As a matter of fact, I think I'm just going to call everybody Paul Love.

That's a beautiful name. Exactly. Paul says this. Given that our universe expanded from a single point and is expanding in all directions, how does that not define the shape of the universe as spherical? How could something flat or saddle-shaped come out of that? So there.

Take that, Jan. Well, it is true. If there is an explosion in space, it tends to have a kind of spherical cloud left over as debris. So when a star explodes, we will see often nebula, and they're like often spherical-ish.

Beautiful too, beautiful nebula. Very beautiful. And you know, sometimes they plow into stuff and it changes shape, but basically, yeah, then you can point inside this debris, point to where the center of the explosion was. So that's not how it works for the Big Bang. So for the Big Bang, you cannot imagine that the space

exists first and that you cannot imagine that the space exists first and that you're exploding into the space. Right. It is actually a creation of the space itself. Self. Right.

So everywhere in the universe was once at the center of the explosion. Exactly. There is no plowing out. It's as though, and you can think of it

any shape you want. Make some crazy, you know, people like the balloon analogy. So now make some crazy balloon twisted up crazy thing. And... A poodle.

A poodle. Oh, nice. A balloon poodle. A balloon poodle universe. And the whole thing stretches. And the whole thing was once a point. So every single point

on that surface. And people get tripped up. It's part of that fabric, if you want to call it. Yeah. So the center is everywhere. The center is everywhere. We are at the center of the Big Bang.

As is every other point in space. Finally, I'm at the center of the Big Bang. But can I say that differently? Will you allow me to say it differently? Please. Can I say, there is a center. The only way you can access it is to go back in time to the beginning of time. Well, you could say...

Ooh, okay. Oh, man, talk about dimensions. So you can access the center of all of this only at one point in this coordinate system, and it's at t equals zero, right? I would say... And it's there. If timeline is just always there, there's the center. Yeah, if we're going to be really, you know, split space up in very fine-grained terms, this

point was at the center back at t equals zero, and this point was at the center back at t equals zero. They just were all closer together. So the whole... So it's just the collapse of those points at t equals zero. Gotcha. Yeah. But I like what you said, though, which I think is what people have to really think.

Yes. The space itself was created at the second, not second, the millisecond, microsecond, whatever, nanosecond. A bajillionth of a second. A bajillionth of a second. That's an official fraction. Right.

The bajillionth of a second afterwards. That space was created then along with everything else. I think that's like 10 to the minus 43 seconds. Yeah, that's right. Which would be a trillion, trillion, trillion, trillion-ish. So, you know, right then. So that, I mean, if you think of it that way, because what you're thinking about is these distances between

the stuff that we see. Yeah. And we think they're empty, but they came from that thing. Yeah. From the big bag. From the big bag. Yeah. So another reason why people get tripped up.

Chuck just blew a gas tank. I know, man. So crazy. We just lost Chuck. I love it. I would love if there was an actual steam effect. Out of the ears? Yeah.

Wow. So, yeah. Wow. Go ahead. So, here's where people get tripped up with the balloon analogy because it's flawed, as are all analogies, is that a lot of people immediately want to point to the center of the balloon, the empty space inside. But you got to give up on that.

All that exists is the skin of the balloon. That is all that exists. I'm okay with the center of the balloon because that's where the balloon was at T equals zero. Right. So you could think of it, good. I can only consider the center of the balloon as snapshots, like movie frames. So it once was there and then it was a movie frame over here. But the center of that same balloon is still now at the outer reaches of that balloon because it came from the center of the balloon.

Right. So imagine you painted dots all over the little infinitesimally small balloon. They were glued to, you know, there's stains on the skin of the balloon. The dots themselves don't move. And then you push all that down so all the dots are together, and then you pull them apart. In some sense, those are the galaxies that came later.

The galaxies aren't moving. The stain on the balloon doesn't move. It's the skin, the stretching between the spots. So, in fact, nothing piles up

the way it does when a supernova explodes. Everything actually just gets more and more diffuse as the universe expands. Holy crap, man. Chuck, you're a gas gas. I got to say, man.

This is Chuck who has his stomach healed. Some good stuff. This stuff is so light. All right, next question. Wild, man. All right, that was great. Thanks, Paul. All right, here we go.

Let's go to Brendan Rico Suave. You just screw with me, Brendan. Okay. Brendan wants to know this. i've recently heard of a new study that states the universe is thought to be in the shape of a loop whereas previously it was thought to be flat but in the explanation given the nature of the loop shape states that it travels far enough in one direction that you'll end up back where you started, which is what we talked

about earlier. My question is, wouldn't this happen regardless of actual shapes of the universe? So his point is like, no matter what you shape it, would that happen?

Yeah. I think that you can say... I think that we have to take a break. Oh! Wow. I should have seen that at the to take a break. Oh! Wow. I should have seen that at the corner of my eye. When we come back,

Jan 11 is going to tell us, do we live in a loop universe or not? On StarTalk. We're back. Cosmic Queries. StarTalk. Chuck Nice, my co-host. Thank you. All right.

Jan 11. Friend, colleague up at Barnard in Columbia. Doing that physics thing. Cosmology. Someone's got to do it. Somebody's got to blow people's cosmological minds. So tell us, as the question Ed asked, would the universe loop back on itself no matter its shape?

So not necessarily. How do you know what shape the universe is in the first place yeah it's really we don't ultimately know the shape we know that we can see the distance light has been able to travel since the big bang because we can't see anything faster than the limit of the speed of light travel time and um and we know that the universe is expanding so that's actually 92 billion light years across about. That's what we call the observable universe. Now, it's possible

that it's not 92 billion light years across and even within that range that the universe has folded back onto itself in some way and we're actually seeing repeats of things.

We're starting to see, it's kind of like a hall of mirrors thing. We're starting to see the light multiple times. How would you know? Yeah, I was going to say, how do you figure that out?

It is very, very hard to figure out. So there have been extremely clever ideas, and most of them rely... If I get my telescope and look at it and I see Chuck waving at me? Yeah, right, exactly. Right, when he was a little baby.

You hear the one about the... So it's true, we're looking at ourselves in the past, which is very hard to distinguish. For instance, if we're looking at galaxies, that's very hard to do. But there are patterns in the hot and cold spots

left over from the Big Bang if it fits into a specific shape. So imagine something just totally platonically beautiful and crazy that the universe is like a dodecahedron,

all of whose faces are glued together. So it's like crazy origami. That thing is, I mean, there it has so many loops. Dodeca, 20-sided triangles.

Right, and that is conceivable kind of what we call topology or connectedness of the space. It would actually start to imprint the patterns of the dodecahedron in the light left over from the Big Bang.

So if you imagine there's tiny little hot and cold spots that you would start to see in the distribution of the hot and cold spots. That shape. That shape would be reflected in a very subtle way. Really? Yeah.

Wow. So the reason the… You don't mean reflected literally. You mean manifested. Manifested. So how the leopard got its spots is actually a very similar mathematical problem because you're asking about enzymes being high or low in the developing embryo and it turns out that the shape and the size of the animal

and like whether it's tubular or when those spots are hitting it that it will determine what kind of spots the animal gets. In an actual leopard zebra stripes like these things are things you can predict by solving for the mathematics of things that are above a certain threshold or below

a certain threshold that that pattern of stripes or spots will reflect the geometry of the animal. And the Black Panther is a leopard. You knew that. Yes, I did know that. And the Black Panther has spots. Now, that I didn't know. It has spots. On its skin.

If you look very carefully, you can see the spots. Oh, wow. Amazing. Well, so how the universe got its spots is a similar mathematical problem. We're solving for hot and cold spots in a particular geometry when the universe was like a developing embryo, basically.

And this goes back to Alan Turing, who solved some of these problems for the animal. But like a black panther, does the universe care about injustices to the black man?

Apparently not, Chuck. Apparently not! I mean, if this is any evidence, if this planet is any evidence. Just to bring that into modern reference. Right. Or does the universe have vibranium?

There you go. I'm just saying. Well, you know, we can hope that we're the bad example. And then elsewhere in the universe there are better examples. Nice. Well said. Well said. All right, Chuck, what else you got?

All right, here we go. This is Tim Braid who wants to know this. A very recent study in the Astrophysical Journal found that galaxies may be rotating in sync with other galaxies millions of light years away. Galaxies separated

by six megaparsecs were found directly interacting with each other. What is your opinion on this? First of all, is that empirical? The fact that these galaxies were actually interacting with one another? I think that that study is probably still

controversial and probably still requires other... Which means probably wrong. I'll be your translator. That's an interesting study means probably wrong. I'll be your translator. Okay, go. I can't say... That's an interesting study. Probably wrong. It's controversial.

Probably wrong. I mean, these things can happen, but it just sounds not that likely. And so there will be a lot of people doing observations in different wave bands with different perspectives to try to break any possibility

that it's a quark of this particular observation. But six megaparsecs, you know, that's pretty far away. And so you would think that you would be dominated there by the expansion of the universe and not interactions. We definitely interact with other galaxies. That's not a big surprise. Just the nearby ones.

Yeah, Andromeda, we're going to collide with Andromeda. That's a happy future. Like, imagine when Andromeda gets much closer, how cool the night sky is going to be. Hey, girl. It's going to be like right there. You're going to collide with Andromeda. That's a happy future. Like, imagine when Andromeda gets much closer, how cool the night sky is going to be. Hey, guys. It's going to be like right there. You're going to see a whole galaxy. No, no, actually, it won't be as cool as you think.

I'll tell you at the end of your answer, though. It's not going to be as cool as you think. Because is it coming in edge-on? No, no, no. I'll tell you why in a minute. It's a disturbing reason why it's not going to be cool. So now speaking of edge-on, now you just, I'm sorry, because I'm a little all over the place,

but I got to get this in before we move on. So speaking of edge on, so if you're looking at something edge on, how do we flip it to get the imagery to know that we were looking at the disk from the edge? So we do that with our own Milky Way. We're in the Milky Way, so we're seeing the rest of the galaxy edge on. Right. We've never seen the Milky Way

as human beings from above. But we have these beautiful constructions because we just map things as accurately as we understand where they are also in space. Okay.

So we just, we build an atlas of it, basically. You build a numerical model based on all of your observations of the Milky Way, the gas, the dust, the stars, everything,

where the spirals are, where the gaps are, and then you just allow yourself to move in that digital world and look down from above. But it's an experiment. So it's the modern version of map making. You can make a map in three dimensions. Once you have a map, you can go anywhere you want.

A three-dimensional map, you can go anywhere. Plus, we see all the gas and we're're kind of flattened in the sky. And there are other galaxies out there that are flattened. And we can see them at all, not one galaxy at different angles, but a million galaxies all scattered in random angles. And so it's pretty easy to figure out what we look like by looking at others. And that's what we look like until we collide with Andromeda.

But one of the things I took solace in, but I feel like Neil's about to make me very uncomfortable. But the whole solar system's supposed to stay together, right? And get knocked around. We should stay together. So we might end up in Andromeda before we fully collide. Like, they could pass each other. They could collide, move through each other,

and we could end up in Andromeda looking at the Milky Way. And the Milky Way, we're going to leave a forward and a dress. But what will, so what will happen is there'll be a lot of sort of dissipated energy and the system, well,

they'll of course pass through each other and back and forth. We've done this on a computer and it's like a rubber band kind of thing and it kind of dies down

and it settles into one double large massive system. Okay, so what's the bad news? Okay, so I hate to break the news. That sounds like good large massive system. Okay, so what's the bad news? Okay, so I hate to break the news. That sounds like good news to me. So, if Andromeda

were a hundred times closer, it wouldn't be any brighter on the sky. Hmm, interesting. Okay, I'm you've lost me. You totally lost me. I'll tell you why. Yeah, tell me why. It's not obvious. Okay, I'm going to tell you.

Yeah. I'm going to tell you? Okay. Can I tell you? Okay. All right. So Andromeda has a certain size on the sky. Correct.

Right. Okay, it has a certain extent. Mm-hmm. And on a very dark night, not in the city, but where the moon is not out, you can see this fuzzy thing in the sky. So that's in the Andromeda galaxy. It's two million light years away. All right.

There's a certain amount of light coming from Andromeda in that patch on the sky. Right. So we reference something called a surface brightness. It is how bright is Andromeda over that patch of sky, over that surface patch on the sky? Surface brightness. Okay. If we bring it half as far away, okay? Make it only half as far.

It is how many times brighter? It should go like the square. Like the square. But then the area is also going. It'll be four times brighter. But the area is going to go like the square. Like the square. But then the area It'll be four times brighter. But the area is going to go like a square. By a factor of four. Yeah.

So, so the whole system is getting brighter, but the surface area is remaining the same. Right. So it is not going to be more apparent to you

in the night sky than our own Milky Way is on our own night sky. Right. I'm very sad to report that. I'm just sad. But it'll look cool. It'll look cool.

No, it'll just still be fuzzy. Can I see it? I've got to get out of the city, get rid of the full moon. Now I see the colliding galaxy. Right. No, I'm sorry. I'm very sorry about this. Okay.

Jenna, I'm sorry to report this. That's all right. I'm, you know. It'll just look like our own Milky Way galaxy. Mm-hmm. Yeah. If Andromeda were right here next to us, it would just look like our Milky Way in the night sky,

which you cannot see from New York City. Which you cannot see from New York City. It is true. But you can see it with one of those apps. Like, you can just, you know. You can hold it. Hold up your smartphone. Hold up your smartphone.

And it could be, like, down there, and it'll show you, like, a beautiful. It'll show you Andromeda on its way. And you pump up the intensity. Who needs eyes? I love it. That's overrated. It is true.

We are practically blind. This is the new model for astronomy. Yeah. Who needs eyes? We're becoming cyborgs. She is so right on this. Chuck. Yeah.

Chuck. Cool glasses. As the centuries went on, we discovered how blind we actually were. Yeah. That's amazing. Yeah. All right. There we go.

Okay. Let's move on to David. Oh, by the way. Go ahead. Those Hubble photos? Yes. If you go to those objects, you don't see what the Hubble saw because the Hubble sees better than you do. Right.

A lot better. A lot better. I mean, if you could just like stare at it for 10 days. Or if your eyeballs were like gargantuan, then it'll look like what the Hubble sees. Right. All right. Cool. All right.

This is David Eduardo Perales Martinez who wants to know. Oh, you did good there. Yeah, well, not bad. My wife is Puerto Rican. Let me hear that again. Go. David, or it would be David Eduardo Perales Martinez. Martinez.

Yes. Who says this, why is it so hard to prove the existence of other dimensions? Thank you. David from Mexico. Yeah. Mexico. I want to ask that a slightly different way. Yeah, go ahead.

If there was another dimension as big as the three that we're in, would it completely manifest to us? Probably. There's a hitch. So you would think, yes, as long as that dimension was very large, then we would be talking about a world in which this did not confine us. Right? So let's say I have skin, which seems to separate my inside and my outside. But if there was another-

Of course, I see right inside you. Right, if there was another dimension, you could do like one of those spooky surgeries without puncturing any skin. You could just like go in there and touch people's organs. Like this would not be a separation of inside and outside. Well, there's also an analogy to that

is if you only live in two dimensions, then you only have sort of height and width, height and, you have height and width but not depth. So if you don't have depth, if I look at you

in two dimensions, I can see all your organs. For you, skin would be a line. And I just reach in and pull out your spleen or whatever. Operation. Operation.

You can't see because you're in the, and all you see is the outer skin, which is just a line. Which is just a line. Yeah, and now our outer skin is a surface. Right. So which is why, you know,

you can't actually probably have a very effective organism in just two dimensions because let's say they had a mouth and a tube going all the way through them, it would actually cut the two sides in half. Yeah. So you can't have what we consider to be normal metabolic functions of...

Okay, anyway. You know what else you don't have? You don't have porosity in two dimensions. Okay, tell me what porosity is. Oh, so if you drop water on soil and then it just soaks in. Right. Or you drop it on a sponge and it soaks in.

Okay. In two dimensions, there's no such thing as... There's no soaking. There's no soaking. No soaking in. Right. Or you drop it on a sponge and it soaks in. Okay. In two dimensions, there's no such thing as... There's no soaking. There's no soaking. No soaking in. Right. So you just have a bulb of water... Bulb of water, correct.

...sitting on top of it. Because porosity enables... You have two... Let's say two rocks are touching here. Mm-hmm. But then the water can just go around another side of the rock. Right. But in two dimensions where they touch, there is no way past it.

Right. It will just stay above it. Is that where you're able to smell what the rock right but in two dimensions where they touch there is no way past it right we'll just stay above it is that where you're able to smell what the rock is cooking okay that was don't worry so here i will tell you this is some some people argue that the reason why the universe is three-dimensional is because the universe tries to be many different ways like well there may have been an infinite number of big bangs in the past and the future. You can't really talk about it in temporal relativeness. But if the universe created a two-dimensionally large universe

with all the rest rolled up and small, you couldn't have organisms in that universe to ask the questions. Wow. So you'd need at least three. And then let's say you had four spatial dimensions. Then you have the problem of things drift away from each other in such a way

that it's hard to have organized systems. So just like Neil was describing, a two-dimensional creature isn't aware of the third dimension. But if they became aware, they could just kind of float away from their city, right? It becomes, you have more volume of space to fill. The cross-section for interaction goes down. So now if you add another dimension, the cross-section for interaction goes down. So now if you add another dimension,

the cross-section for interaction goes down again. No, but we successfully exist in three dimensions in spite of the challenges the two-dimensional creature would face upon accessing a third dimension. Right. So why aren't... Maybe three is optimal.

Why don't four-dimensional creatures pity us? Yeah. Right. Well, that is a good question. Could the complexity... Maybe three is optimal. Why don't four-dimensional creatures pity us? Yeah. Right. Well, that's, I mean, that is a good question. Could the complexity, like, I'm just, I'm not saying they're true arguments, but some people argue that you couldn't in the four dimensions get the successful complexity. And some of those arguments are, they get, you know, complicated based on string theory, cross-sections and annihilations into photons and what's left over after all of these things

and the Big Bang, it turns out that only a tiny, tiny bit of stable matter is left over already in three dimensions from the Big Bang. Wow, so it could be. Wait a minute. Let me kind of agree with what you just said, even though I just disagreed. Yeah.

What you're saying is, in three dimensions, it could be optimal for particles to get together and make molecules and molecules to make macroscopic objects. If you add a fourth dimension, you're adding a degree of freedom of where things

can hang out and possibly never then find each other ever again. If you think about the volume of the universe as going up radically with the volume of dimensions, then you're diluting everything in the universe significantly. The concentration of what could be. Ooh.

Interesting. So the fact that you're even asking that question means you are a being in an optimized universe to even pose the question in the first place. So the two-dimensional people couldn't ask this question? Right, because they couldn't be two-dimensional people because the structures are too simple to allow. And four-dimensional people, there's too much play space.

So let's take it. Your first question was, would we know it if the other dimensions were large? Here's the hitch. You would think we would, but here's the hitch. Even if all of those problems were solvable, there is an argument that we could be glued to a kind of a membrane,

which is a three-dimensional surface floating in this higher dimensional space. And we're like glued to it. Elmers. Elmers. The way the fundamental forces work between... They keep us there. They keep us on the membrane.

And the only thing that happily goes off the membrane is gravity itself. Right. So that all other forces are glued to this membrane. That's where they live. So that you would think like a particle to you interacting with that membrane could be a string in the higher dimensional space.

Passing through your space, manifesting as a particle. Manifesting as a particle. So like imagine cutting a string, it would look to you like a dot. Manifesting as a particle. So like imagine cutting a string, it would look to you like a dot. Right. An infinitely thin string.

And that is wild. The way I think about in two dimensions, I think of passing a hollow sphere through two dimensions. What would that look like to the two dimensional people?

They'd see a dot and say, well, that's cool. Oh, then it becomes like a circle. And it gets bigger and bigger and bigger. Then it maximizes out at the diameter, but they don't know this. And then it. Oh, then it becomes like a circle. And it gets bigger and bigger and bigger. Then it maximizes out at the diameter,

but they don't know this. And then it gets smaller, then it gets a point and disappears. And they have no idea. They have no idea. And all kinds of mystical, magical hypotheses come out. And the scientists analyze it. We just say stuff pops in and out of existence.

We don't know why. So one of the, yeah, absolutely. So one of the things that we've worked on with Extra Dimensions that make them not just an oddity, but maybe something we've already observed. One of the things we've worked on on our Extra Dimensions. Jan, what's in your basement? She's a superhero nemesis character in the making.

My superhero character name is Jan Eleven. Isn't it good? And it's a prime number is Jan 11. Isn't it good? And it's a prime number. Jan 11. I mean, I've got to work that somehow. No, no, no. You don't want to be the superhero. You want to be the nemesis.

That's way more fun. Oh, that's fun too. It is way more fun. Because then you can be diabolical with the science. That's Jan 12. My evil twin, Jan 12. My evil twin, Jan 12. So the interesting thing there that people have thought about

is that maybe something like dark energy is actually a quantum phenomenon trapped in the extra dimensions that we can't perceive the extra dimensions directly, but we're indirectly perceiving them through the dark energy. Or dark matter is regular matter in the higher dimensions leaking over into this membrane. And we're just doing this, and it's just mysteriously there. Yeah, people have definitely wondered if that matter could have to do with extra dimensions.

So gravity is the thing that is the medium? Is that the deal? Gravity is space-time, so gravity can't be confined. Gotcha. Otherwise, there would be no meaning to the extra dimension. Stupid. Everybody knows that. Everybody knows that. Everybody knows that, Chuck.

Chuck, we've got to take a quick break. Okay. When we come back, more with Jan 11 on the edge of the universe and beyond when StarTalk returns. Hey, we'd like to give a Patreon shout out to the following Patreon patrons. Roy Hill Percival, Jose Clark, and Dr. Janet L. Walsh. Thanks so much, guys, for helping us make this little trip through the cosmos. And if you would like to support us on Patreon, go to patreon.com we're back star talk cosmic queries the edge of the universe there's only one person in arms reach out there that who could do this janelle janna Jana. She's our go-to person.

Yes. I love being the go-to person. It's the best. Totally the best. I have actually written papers on extra dimensions. It is a genuine direction in my research

is to think about this. So when she disappears, we'll know. We'll know. Wouldn't that just be so cool? Yeah. I just got up and then went into

the fourth dimension. This is how Monsters just be so cool? Yeah. Buzz just got up and then went into the fourth dimension. And then might just disappear. This is how Monsters, Inc. worked. Yeah. Oh, yeah. Monsters, Inc. These are doors that came out of the factory. Right.

This was an uncelebrated fact of that movie. These are four-dimensional portals. They're basically wormholes. They're amazing. Each door, this is the door to the kids' room. And the monster takes it home at the end of the day. And they open the door. And on the other side of the door is the kid's room. And the monster takes it home at the end of the day, and they open the door,

and on the other side of the door is the kid's closet. Right. Nice. So great. And then they come out of the closet, scare the kid, go back through the door, and they're back at home. It is a great movie. Okay.

I love it. All right. Let's go to, you know what? Let's go back to a Patreon patron. This is Solarcero de Rai, okay, who says, what do y'all think about the... You like that? I like it.

I'm good. I'm good. What do y'all think about the idea that matter consumed by black holes has been recycled and manifested back into the universe as dark energy? So matter coming out the other side, maybe. Right. Okay. Is there any correlation between the matter consumed by black holes and dark energy?

Could black holes and dark energy, dark matter, be different sides of the same coin? Well, I mean, where to begin with this? This is a lot. I can lead off by saying there's an urge to take everything you don't know and assume it's related right

so I've got people talking about dark matter consciousness God and dark energy all as one thing right

and quantum and quantum spookiness yes someone asked me when they take ayahuasca is it possible that they have gone to a higher dimensional space?

Okay. Okay. But my answer in an attempt to not be totally dismissive was to say, well, if it's a platonic form that we can learn about by exploring the mind, then in that sense, maybe. Right. Like a perfect circle doesn't exist in reality, nor will a perfect circle ever exist anywhere in the universe. But you can touch it in your mind, right? And it's an experiment we can all perform so that in that sense we go places.

Unlocking secrets of the mind, if not secrets of the physical universe itself. Yes, yes. In other words, you high. So what do you say about dark matter, dark energy? So let's just start with the falling in, coming out. So there were very early on people who thought a black hole could be bigger on the inside than the outside.

It could be as big as an entire universe on the inside. It could actually lead to a white hole, which is basically a big bang. So you fall into the black hole, and that is completely confined by the event horizon. Nothing ever comes out, but inside it is like something as big as an entire universe. Right. Another universe.

And that universe will remain like a TARDIS. Like a TARDIS. Exactly. It's just like Doctor Who's TARDIS. And so we would never know about that universe. It would not communicate with us. Check Chuck's Street Cred. TARDIS is an acronym for what?

Oh, no. Oh, no. I can't remember it all. Phone booth in London? Yes. I don't know. Time and relative dimension in space. Time and relative dimension in space. Time and relative dimension in space.

TARDIS. There you go. Usually the and doesn't make it into the acronym, I'm just going to say. You know. Okay, so that was an interesting idea, and a lot of people object to it because it in some subtle way suggests an unstableness

to Big Bangs that might make it so that this world couldn't be stable if that were true. But honestly, it's not completely off the table. There's a lot. You could talk to some very important early relativists, and they will still say that's what happens. Relativists, an expert on relativity. On relativity.

So then there's a separate, totally separate question about dark matter. There is a suggestion that the black holes themselves could be dark matter, meaning that they are invisible, like dark matter is, technically, and they could populate the universe almost arguably large enough to explain this missing mass, this missing matter. It's on the edge. It's definitely under pressure.

Right, but there's a problem with, like, Big Bang nucleosynthesis. If it's ordinary matter... The black holes don't Big Bang nucleosynthesis. If it's ordinary matter. The black holes don't have to be made by collapsing stars out of ordinary matter. But you're absolutely right. We don't know how to make enough ordinary matter. Right, so they're not made from stars.

So can I show you my black hole lunchbox? Oh, let's do it. I want to know what's inside the lunchbox, but I can never find out. You can never, if you go in, she will never come out. She will never come out. If my hand go in, she will never come out. If my hand goes in, will it never come out?

Exactly. And inside of it is a black hole thermos. But of course. It is confusing. If you fall into a black hole like this, I guess you can't see your hands. Very confusing. You'll disappear in front of yourself. So you have a black hole thermos and it is filled with...

Okay, so... Liquor. This is an inversion of the known universe. Because in this particular case... Inside your black hole... I have the Milky Way inside the black hole. No, you did not. He did that, yes.

No, you just did not do that. You totally did that, sir. You did not just pull a Milky Way out of a black hole. No, you did not. He did that, yes. No, you just did not do that. No, you did that, sir. You did not just pull a Milky Way out of a black hole. Because the black holes are always inside the Milky Way. I am just going to say that that was the most committed joke I have ever seen in my life. For those of you who don't have a camera, I'm just telling you, Neil had an actual Milky Way candy bar inside of a black hole thermos. Inside my black hole lunchbox.

Inside of his black hole lunchbox, okay? You're just jealous. That's all. I'm a little jealous of the black hole lunchbox. Definitely a little bit jealous. So the last question, which is pretty hard, is could they all be connected, the stuff that falls in and comes out? And classically, we would say no way.

Van der Huizen separates everything from the inside to the outside, but then there's like quantum entanglement across the Van der Huizen. Maybe some particles on the inside are also the same thing as the particles on the outside. They're the same particles because of entanglement and wormholes

and some crazy stuff that nobody really, it's all just very conjectural now, but maybe we'll come back in 20 years and we'll be like, figure that out. We'll have something for it. We'll have a follow-up to this Cosmic Queries 20 years from now. Yes, exactly. We'll roll us in wheelchairs, not you, but me and Chuck. Because I'll be doing my regenerative medicine.

So we got to go lightning round here. Chuck, let's do it. Here we go. So Jana, you're going to answer each sound bites. Okay. Amped. This is bunders85 on Instagram and wants to know this. I know it's off topic, but one of your last shows,

you were talking about the information on the surface of a black hole. What do you mean by information? Do you mean temperature or speed? What is information? Ultimately, we are completely definable in terms of our quantum numbers. It's just a list of facts about us, information about us, and relative locations and organizations. My quantum number is 42.

So, of course, Niels has. It's something as simple as your mass electric charge. The number of atoms in my body. Let's take a single fundamental particle in your body. It has mass charge spin, and it's identical to every, let's call it an electron in this case, every other electron, identical. One's not a little bit heavier, one's not a little bit lighter. We're completely definable in terms of that information.

And you cannot destroy that information. Interesting. And so in quantum mechanics, you start to stop thinking. Wait, wait, if I melt Chuck and he's a puddle. Technically, all of that information is still in the universe. Right, it's just arranged differently. It's just arranged differently. Oh, my God.

In principle. Wait, wait, wait. How about the information? That's an awful thought. If Chuck is a puddle on the ground, that's a different Chuck from the Chuck I'm talking to right now. How's that information still there? I will never change.

Well, technically... Having information preserved doesn't mean there can't be local change, right? So I can definitely change things locally, but I still have to have the same information content. In the total system. In the total system. So I have to be able to reconstruct something.

It doesn't mean that there's no change. With what's in the system. With what's in the system. Got it. But you don't have to necessarily be able to reconstruct the exact same thing. You just have to be able to utilize the same information. Right. In principle, I should be able to, if I took a page of the encyclopedia and burnt it, I

should be able to reconstruct it. In principle. Of course, nobody can ever really do that. It would take longer than the age of the universe, and we don't have that kind of computing power. So there's physical impossibilities, but- Ignoring those complications. Ignoring those complications. Ignoring those complications. We've just solved teleportation.

For the black hole, the argument is that what actually might be happening is that the information as it's falling in, which is basically everything, never actually makes it inside the black hole. It becomes encoded on the boundary, which is the event horizon,

so it's actually a hologram. We're lightning round here. That was not lightning enough. That wasn't lightning enough. Okay, here we go. This is Elias82 from Instagram says, NASA reported that Voyager 2 discovered two new details

about interstellar space. How does that change our understanding of dark energy beyond our solar system? Or does it? It probably doesn't because it isn't a detector of dark energy or dark matter.

We have no detectors of dark energy or dark matter yet. None successful. And so, but it is amazing that it's the first human-made object

that's gone interstellar. And that really is quite spectacular. It's just broken out of basically the sun's magnetic influence so it's able to get cosmic rays and things that are protected just broken out of basically the sun's magnetic influence, so it's able to get cosmic rays and things that are protected

in the solar system by the sun's magnetic flow. We used to think the solar system was how far out are the planets. And then you have like the Kuiper Belt of Commerce, then you have the Oort Cloud. Then you say, well, really at what distance does an object no longer know that the sun is in this direction? Right. Because the sun has magnetic

influences that go very far, and you reach the point where all the field measurements are sort of in this soup that permeates the entire galaxy. And so it's a transition from the sun is this way to I got stars in every direction.

Yeah. Right. It's still moving so slowly that it will take, what, 10,000 years to reach another. No, no, no, 70,000 years. 70,000 years. All right.

We're liking Rob. This is from Robert Weber, who says, thanks so much for educating and inspiring us. What news in science do you find most interesting and important right now with respect to your field? Wow, that's a great question. Well, we do live— In a soundbite. Yeah. field? Wow, that's a great question.

Well, we do live... In a soundbite. Yeah. We are in a very lucky time because we have discovered bare black holes in this miraculous way. So I do think that the most exciting things have to do... And one of them has a Milky Way inside. One of them has... Yeah, is eating Neil's Milky Way. So I do think it is where the small meets

the large, and it will be that way for a long time, meaning what the Big Bang tells us about dark matter and dark energy and the universe on the larger scale and why those things are folded together, thinking about the universe on the biggest scale and on the small scale. So where quantum physics meets general relativity

is an unresolved territory. That's right. And so that's why we use all these really extreme settings. If you want to understand where quantum mechanics meets gravity, you've got to do it in the Big Bang or on black holes. All right. Next, Chuck.

Here we go. This is Pablo Gristensko. I don't know, Pablo. I'm sorry. Can you please help me put inside my head one more dimension? Three is fine, but how can I grasp more? What do you do with people to let them understand? I think it is absolutely imperative that everyone understands that nobody can just blanketly visualize higher dimensions. We're accustomed to looking at dimensions from the

outside looking down. We can't do that. So what we can do are the kinds of things that Neil was describing earlier, which is imagine three-dimensional cross-sections of things. So visualizing a hypersphere, which is a higher-dimensional sphere, as an intersection of it with our three dimensions, and it would be a series of spheres that would max out, and then spheres would go back. But one last thing is to do the difficult example of being a flatlander, and you will actually, just by going down a dimension, start to get it.

And I can add that if, I've said this in a couple of Star Talks before, but here's another moment to do so. If a line is bounded by points, and a square is bounded by lines, and a cube is bounded by lines, and a cube is bounded by squares, then a hypercube is bounded by three-dimensional cubes. The sides of a hypercube are three-dimensional cubes. Right. And you just, mathematically, you just work your way up.

You just keep going up, and the math will take you there. There you go. Math will set you free. There you go. Math will set you free. There you go. This is a real example where the math makes it a lot easier than trying to visualize it.

Okay, there you go. Said no one ever. Let's convert this to math to make it easier. That's so great. That's your higher dimensional differential geometry. That's awesome.

All right, go. Okay, this is Eric Spenson. Mark Eric Spenson. He says this. Neil, you have said before the dark matter should really be called dark gravity, and it really stuck with me and helped me understand it better. Do you have a similar and alternate name for dark energy that better summarizes the phenomenon?

I'll give it a shot, but I want to hear. Let's see what Jana says. What Jana says. Jana. I would say, I would just call it dark expansion stuff. We don't know what energy. Dark stretching. Stretchy stuff.

Dark stretchy. But definitely dark gravity is what dark matter is. It is literally dark gravity. And I'm totally cool with that. Are you totally cool with that? Totally cool with that. Is a neutrino dark gravity? Uh-oh. Sure. That's a form of dark gravity. And I'm totally cool with that. Are you totally cool with that? Totally cool with that. Is a neutrino dark gravity? Uh-oh.

Sure. Because that's a form of dark matter. Like, we have examples of forms of dark matter that we have detected. They're just not plentiful enough to explain so much of it. Yeah.

But there are things called neutrinos which we do detect and they are dark, meaning they don't interact with light. Right. I wouldn't call neutrinos dark gravity. Wow. I'm pushing back a little on this.

I'm pushing back. You're messing with me. Let me tell you something. That was rough, man. Uh-oh. You got front row seat. Yeah, I'm nerd fight. Right now, I got my popcorn.

I'm just like, nerd fight. Oh, this is good. I will jump in with the dark energy, though. What if we thought of it as like an invisible ocean? Because that's sort of what the dark energy is around us all the time and it's as though we're in a storm of dark particles and dark energy.

It's really that it's invisible is the thing. You can see right through it. It's not that if you had it in your hands, it would look dark. It's invisible. So both dark and energy really don't apply. We need It's invisible. Right. Right. So, yeah, so both dark and energy really don't apply.

We need a better name for it. Yeah. Okay. There you go. So it's really in the name. Vacuum bath. Next one. All right.

Last one. Last one. Real fast. Okay. Okay. Okay. Jenna, half a sound bite.

Here we go. This is Hector Salazar who says this. Can other universes influence or overlap with our own? And is there any evidence that this might be happening? This would be the parallel universe. Yeah, very speculative. But if you consider a universe, let's say we're floating on a three-dimensional membrane in a

higher dimensional space, and there's another one of those floating also in the higher dimensional space, parallel, or in some sense. Now do they both share this membrane you're talking about? No, they're different membranes. So in that sense we would call them universes. And yes, it is possible that they have interacted in the past and that there would be some archaeological record of that or in the future.

If they intersect, is there an intersection line, a three dimensional line. In which you live in both universes. Like a party-dimensional line. In which you live in both universes. Like a party wall. So technically, if you mean by universe, the galaxies and everything you see, and not the whole space-time, then technically, yes, two universes,

two membranes can interact and can coexist. I want that. I like the idea of living on the boundary between two universes. Only if the people in the other universes aren't a-holes. And as long as the laws of physics there are the same as yours. Same as ours. Because you don't want to decompose into a bubble of goo. Yeah.

That would be bad. That would be bad. If the charge of the electron is different. Bad. Bad. Very bad. Bad universe. Stay away.

We got to call it quits there. Oh, man. Janet, always good to have you on. It's always fun to be here. We don't have you enough. Oh universe. Stay away. We got to call it quits there. Jen, it's always good to have you on, Jen. It's always fun to be here. We don't have you enough. Oh, I love it. Thanks. So much fun. So much fun.

Jen Levin, professor of physics up at Columbia and Barnard College. I'm Neil deGrasse Tyson, your personal astrophysicist, signing off for StarTalk, bidding you, as always, to keep looking up.