Latest / Daniel and Kelly’s Extraordinary Universe / Great, Big Questions about the Universe

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Great, Big Questions about the Universe · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, or hey, if you had to leave a Yelp
• 0:11
  Speaker 1: rating or for the universe, what would you give it?
• 0:14
  Speaker 2: Can I give it like a trillion trillion stars?
• 0:18
  Speaker 1: I think that might break their database. But I'm guessing
• 0:21
  Speaker 1: you're saying that the universe is pretty great.
• 0:24
  Speaker 2: Yeah, it's pretty great in a lot of ways.
• 0:26
  Speaker 1: Right, you mean great is in it's awesome.
• 0:28
  Speaker 2: It's awesome, and it's also really big. It's a great
• 0:31
  Speaker 2: big universe.
• 0:32
  Speaker 1: Hey, that's a catchy phrase.
• 0:34
  Speaker 2: Yeah, somebody should use it for the title of a
• 0:36
  Speaker 2: new book.
• 0:38
  Speaker 1: That's a great big idea.
• 0:55
  Speaker 2: Hi am Poorham, a cartoonist and the author of the
• 0:57
  Speaker 2: new book Oliver is Great, Big Universe.
• 1:00
  Speaker 1: Hi. I'm Daniel. I'm a particle physicist, and I also
• 1:03
  Speaker 1: think the universe is pretty great and big.
• 1:05
  Speaker 2: It's a great big universe.
• 1:07
  Speaker 1: Great also means big, doesn't it? Or isn't that part
• 1:10
  Speaker 1: of the etymology of great?
• 1:11
  Speaker 2: I think technically can mean several things, like it's great,
• 1:14
  Speaker 2: like you like it, but also like it's great, like it's.
• 1:16
  Speaker 1: Big, Yeah, like great Britain. Right, it's pretty great and
• 1:19
  Speaker 1: also big and pretty British. But anyways, welcome to our podcast.
• 1:23
  Speaker 1: Daniel and Jorge Explain the Universe, a production of iHeartRadio
• 1:27
  Speaker 1: in which we try to accomplish a feat which sounds impossible,
• 1:30
  Speaker 1: to download the entirety of this great, big universe into
• 1:34
  Speaker 1: your mind, to summarize all of the whizzing and banging
• 1:37
  Speaker 1: and frothing and tewing and frowing of the tiny little
• 1:39
  Speaker 1: particles that make up this universe into a mathematical story
• 1:43
  Speaker 1: that somehow makes sense to these grown up apes.
• 1:46
  Speaker 2: That's right, because it is a great, big universe full
• 1:48
  Speaker 2: of amazing facts that we like to talk about here
• 1:50
  Speaker 2: on this podcast, and also rate I guess with stars.
• 1:54
  Speaker 1: The universe is definitely filled with stars, big glowing stars
• 1:58
  Speaker 1: and also you know, blowing up pop stars.
• 2:00
  Speaker 2: Well, hopefully I'm not literally blowing up, but it is
• 2:03
  Speaker 2: filled with stars, planets, asteroids, galaxies, dark matter, dark energy,
• 2:08
  Speaker 2: and also people young and old. We're here to ask
• 2:11
  Speaker 2: questions and also sometimes answer them about the universe.
• 2:14
  Speaker 1: That's right. We think everybody should be curious about the universe.
• 2:17
  Speaker 1: When you stare up at the night sky, we want
• 2:19
  Speaker 1: to know what makes you wonder, What questions do you
• 2:21
  Speaker 1: have about how it all works? Not just the earth
• 2:24
  Speaker 1: that's under our feet, but the whole big, great universe
• 2:27
  Speaker 1: out there.
• 2:28
  Speaker 2: Yeah, and speaking of great big universe, we are here
• 2:31
  Speaker 2: to celebrate the release of my new book called Oliver's
• 2:34
  Speaker 2: Great Big Universe, which is out now and you can
• 2:36
  Speaker 2: go out and buy it.
• 2:37
  Speaker 1: Yeah, congratulations. Tell us a little bit about the book
• 2:40
  Speaker 1: and why you wrote it.
• 2:41
  Speaker 2: Yeah, it's an awesome book. It's maybe the only book
• 2:43
  Speaker 2: that is endorsed by Jeff Kinney, the author of Diary
• 2:47
  Speaker 2: of a Wimpy Kit, and also Carlo Rovelli, the theoretical physicists.
• 2:51
  Speaker 1: That's quite a collection. Do you have to be a
• 2:52
  Speaker 1: cartoonist or a theoretical physicist to read it?
• 2:54
  Speaker 2: Absolutely not. I actually wrote the book for kids who
• 2:59
  Speaker 2: wouldn't normally pick up a science book, and also for
• 3:02
  Speaker 2: anyone out there who's interested about the universe. Yeah.
• 3:04
  Speaker 1: Tell us a little bit about your approach. How do
• 3:06
  Speaker 1: you attract people who aren't usually into science.
• 3:09
  Speaker 2: Well, the book again is called Oliver's Great Big Universe,
• 3:11
  Speaker 2: and it's about the story of this eleven year old
• 3:13
  Speaker 2: kid named Oliver, who one day decides he wants to
• 3:17
  Speaker 2: be an astrophysicist, but of course, being eleven years old,
• 3:20
  Speaker 2: he doesn't quite know what that means, and so the
• 3:23
  Speaker 2: whole story is about him trying to figure that out
• 3:25
  Speaker 2: and also him explaining to other kids all of these
• 3:28
  Speaker 2: amazing facts about the universe. So there's chapters about black holes,
• 3:32
  Speaker 2: there's a chapter about dark matter and dark energy. There
• 3:35
  Speaker 2: are chapters about the planets, and there are chapters about
• 3:38
  Speaker 2: the time as well.
• 3:39
  Speaker 1: And don't you, by coincidence, have an eleven year old
• 3:42
  Speaker 1: named Oliver.
• 3:43
  Speaker 2: Yes, it is not a big coincidence. So the whole
• 3:45
  Speaker 2: book was kind of inspired by my son when he
• 3:48
  Speaker 2: was in fifth grade. He came home one day and
• 3:50
  Speaker 2: at the dinner table he announced he wanted to be
• 3:53
  Speaker 2: an astrophysicist, and so we were like, do you know
• 3:55
  Speaker 2: what that means? And he's like, I have no idea,
• 3:58
  Speaker 2: and yeah, that of like confidence and shuitspa and curiosity
• 4:03
  Speaker 2: is kind of what inspired the whole book.
• 4:05
  Speaker 1: So what's it like when a cartoonist has his son
• 4:07
  Speaker 1: saying I want to be a physicist. Is that like
• 4:09
  Speaker 1: when a physicist has a son who says I want
• 4:11
  Speaker 1: to be an artist?
• 4:12
  Speaker 2: Yeah? Kinda? Are you gonna go no? No, it's cool.
• 4:15
  Speaker 2: He's always been kind of a science kid. He's always
• 4:18
  Speaker 2: been interested in science. He's in the math teams, in
• 4:21
  Speaker 2: the Science Olympics team, and so it wasn't super surprising
• 4:24
  Speaker 2: that he says that he wants to be an as
• 4:26
  Speaker 2: a physicist. But it's pretty cool. Yeah, we try to
• 4:28
  Speaker 2: encourage it, for sure.
• 4:29
  Speaker 1: Awesome. Well, something we encourage in our podcast listeners and
• 4:32
  Speaker 1: their kids is asking questions, is thinking about the universe,
• 4:36
  Speaker 1: is wondering if they want to be an after a
• 4:38
  Speaker 1: physicist when they grow up and what exactly that entails.
• 4:41
  Speaker 1: And step number one of being an after physicist is
• 4:44
  Speaker 1: just looking up at the night sky and wondering what's
• 4:46
  Speaker 1: out there, how does it all work? What is in
• 4:49
  Speaker 1: our great, big universe?
• 4:51
  Speaker 2: Yeah, and so to celebrate the release of the new book,
• 4:53
  Speaker 2: we are answering listener questions from kids today.
• 4:56
  Speaker 1: That's right. I went out there and asked our listeners
• 4:59
  Speaker 1: to ask their kid kids what questions they had about
• 5:02
  Speaker 1: the universe. And so today we'll be tackling a few
• 5:05
  Speaker 1: of those.
• 5:06
  Speaker 2: That's always a risky thing to ask your kids what
• 5:09
  Speaker 2: kind of questions they have or did you make it
• 5:11
  Speaker 2: specific about the universe?
• 5:12
  Speaker 1: I made it specific about the universe, which makes it
• 5:15
  Speaker 1: totally generic.
• 5:16
  Speaker 2: I guess the universe is everything, even the uncomfortable parts.
• 5:20
  Speaker 1: Ask me a question, but only about anything in the universe.
• 5:24
  Speaker 2: Right, So we have several questions here from kids about
• 5:26
  Speaker 2: all kinds of things about the universe, from suns and
• 5:29
  Speaker 2: black holes to the infinity of the universe. So the
• 5:33
  Speaker 2: first question comes from Violet. The cause of sun is
• 5:36
  Speaker 2: still a star until one day collapse like other stars
• 5:40
  Speaker 2: and turn into a black hole. Mmmm. That is a
• 5:44
  Speaker 2: deep question from a small mind.
• 5:46
  Speaker 1: I love. Even in that brief question, you can hear
• 5:48
  Speaker 1: her train of thought. She's connecting our star to other stars.
• 5:52
  Speaker 1: She knows that other stars collapse into black holes, and
• 5:54
  Speaker 1: then she was reflecting that knowledge back here and wondering
• 5:58
  Speaker 1: about the fate of our star. All the connection she's making,
• 6:01
  Speaker 1: all the physics you can hear happening in her brain.
• 6:03
  Speaker 2: Yeah, it's pretty awesome. And the sun is something I
• 6:06
  Speaker 2: think all kids can relate to, right, I mean, everyone
• 6:08
  Speaker 2: sees it every day, maybe not directly, but we're all
• 6:11
  Speaker 2: basking and its light.
• 6:12
  Speaker 1: I don't know, she sounded like she had an accent.
• 6:14
  Speaker 1: She might not see the sun that often out in
• 6:17
  Speaker 1: Great Britain. It's pretty cloudy.
• 6:19
  Speaker 2: M Well, some parts of it are, sonny, aren't they.
• 6:22
  Speaker 1: Let's hope.
• 6:22
  Speaker 2: So I do have a whole chapter in Oliver's Great
• 6:24
  Speaker 2: Piginius about the Sun, which it's a nice coincidence. It's
• 6:28
  Speaker 2: kind of fun to explain it in terms that kids
• 6:30
  Speaker 2: can't understand. And so let's dig into violid question here.
• 6:33
  Speaker 2: She wants to know if our sun is going to
• 6:36
  Speaker 2: collapse into a black hole, because I guess she said
• 6:38
  Speaker 2: that other stars collapse into a black hole.
• 6:40
  Speaker 1: Yeah, there are a lot of black holes out there,
• 6:42
  Speaker 1: sort of two varieties are the kind of the center
• 6:45
  Speaker 1: of galaxies, which are called super massive black holes, really
• 6:48
  Speaker 1: really big ones, and nobody really knows where those come from.
• 6:51
  Speaker 1: It's kind of a mystery. But then there's lots of
• 6:54
  Speaker 1: smaller black holes out there which come from stars at
• 6:57
  Speaker 1: the end of their life. These stars have collapsed into
• 7:01
  Speaker 1: a black hole. And so she's wondering about those. And
• 7:04
  Speaker 1: black hole is the endpoint of some stars. Not every
• 7:07
  Speaker 1: star is going to end up as a black hole.
• 7:09
  Speaker 1: And to understand why some stars become black holes and
• 7:12
  Speaker 1: others don't, you have to understand something about the balance
• 7:14
  Speaker 1: of forces that are keeping a star burning in the
• 7:16
  Speaker 1: first place.
• 7:17
  Speaker 2: Yeah, I guess it's a big point to know that
• 7:19
  Speaker 2: not all stars are the same. They're all different, and
• 7:21
  Speaker 2: they mostly differ in size, right, and like the amount
• 7:25
  Speaker 2: of stuff that's in them.
• 7:26
  Speaker 1: Yeah, stars come from the collapse of a big cloud
• 7:28
  Speaker 1: of dust and gas that forms a denser blob. But
• 7:32
  Speaker 1: a cloud can sometimes make lots of stars, and you
• 7:34
  Speaker 1: can get smaller stars or more massive stars. It depends
• 7:37
  Speaker 1: a little bit on the configuration and whether there was
• 7:39
  Speaker 1: like a supernova shockway that triggered it, and whether you
• 7:41
  Speaker 1: had like a cluster of heavy metals in the center
• 7:43
  Speaker 1: to gather stuff more rapidly. So there's a big variation.
• 7:47
  Speaker 1: The bigger stars are less likely and they burn hotter
• 7:49
  Speaker 1: and shorter, and the smaller stars are much more common
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  Speaker 1: and they can burn for a long time.
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  Speaker 2: And as you said, it's kind of a balance of
• 7:56
  Speaker 2: fusion and gravity, Like there's stuff exploding in the middle,
• 8:00
  Speaker 2: but there's also gravity trying to squeeze the whole thing down. Right.
• 8:03
  Speaker 1: Gravity is what gets things started. You tug a little
• 8:06
  Speaker 1: pebble here and a little bit of cosmic dust over there,
• 8:08
  Speaker 1: and then you get this runaway effect where it gets
• 8:10
  Speaker 1: stronger and stronger gathering stuff together. And if there was
• 8:13
  Speaker 1: only gravity, then any accumulation of stuff would turn into
• 8:16
  Speaker 1: a black hole because it'd be nothing stopping it from
• 8:18
  Speaker 1: getting infinitely dense. But there are other things in the
• 8:20
  Speaker 1: universe than just gravity, Like the Earth doesn't collapse into
• 8:23
  Speaker 1: a black hole. You don't collapse into a black hole
• 8:26
  Speaker 1: because your body or the Earth's structure is strong enough
• 8:29
  Speaker 1: to push against that gravity. Gravity is a huge force
• 8:31
  Speaker 1: in the universe, but it's not very powerful, so it's
• 8:34
  Speaker 1: not actually that hard to overcome.
• 8:36
  Speaker 2: Yeah, but on a sun, that what keeps the whole sun,
• 8:38
  Speaker 2: the whole cloud of gas from collapsing, is fusion, right,
• 8:42
  Speaker 2: it's the nuclear reactions that are happening in the middle exactly.
• 8:44
  Speaker 1: We call it a radiation pressure. That fusion is like
• 8:47
  Speaker 1: an explosion. It's shooting out photons, it's pushing out on
• 8:50
  Speaker 1: all the stuff. And that balance is the gravity of
• 8:53
  Speaker 1: the star. It's sort of amazing that those things can
• 8:55
  Speaker 1: be in balance and be in balanced for so long.
• 8:58
  Speaker 1: Stars can burn for millions or billions. We think some
• 9:01
  Speaker 1: small ones might even burn for trillions of years. It's
• 9:05
  Speaker 1: an incredible balancing act.
• 9:06
  Speaker 2: Yeah, it's pretty wild now that I think about it,
• 9:09
  Speaker 2: to think that it is stable, right, like it could
• 9:10
  Speaker 2: have been the case that suns and stars are not stable.
• 9:13
  Speaker 2: They could either fizzle out pretty easily, or maybe they
• 9:15
  Speaker 2: could have blown up more easily, exactly.
• 9:17
  Speaker 1: And if you get a star that's big enough, like
• 9:19
  Speaker 1: more than three hundred times the mass of our sun,
• 9:22
  Speaker 1: then it gets so hot and so intense at the
• 9:24
  Speaker 1: core that it really does blow itself apart. They don't
• 9:27
  Speaker 1: last very long. There's an interesting range of masses. As
• 9:30
  Speaker 1: you say, the initial scoop of stuff that you get
• 9:33
  Speaker 1: really determines the outcome. And I guess we're just kind
• 9:36
  Speaker 1: of lucky that there are lots of stars that can
• 9:38
  Speaker 1: burn long enough to make our universe bright.
• 9:40
  Speaker 2: I guess they're sort of like candles, right, Like a
• 9:42
  Speaker 2: candle burns for a long time because it has this
• 9:44
  Speaker 2: kind of balance of that it can burn, but it
• 9:46
  Speaker 2: can't burn too much or too fast exactly.
• 9:48
  Speaker 1: That's why you like to build a candle instead of
• 9:50
  Speaker 1: a bomb. Right.
• 9:52
  Speaker 2: That'd be hard to light up your home with bombs, right.
• 9:56
  Speaker 1: I don't recommend anybody reads Jorge's new book By the
• 9:58
  Speaker 1: Light of Bombs, Please get can those if you don't
• 10:00
  Speaker 1: have light bulbs?
• 10:01
  Speaker 2: Yeah, yeah, or a flashlight as well.
• 10:03
  Speaker 1: That works a little safer exactly. But it's not just
• 10:07
  Speaker 1: radiation pressure that can keep something from collapsing into a
• 10:10
  Speaker 1: black hole, because eventually that radiation pressure gives up when
• 10:13
  Speaker 1: you've burned up all the fuel in your star, when
• 10:15
  Speaker 1: you've turned all that hydrogen into helium or something heavier,
• 10:18
  Speaker 1: then you're not fusing anymore. But even still, not every
• 10:21
  Speaker 1: star that finishes all of its fusion will turn into
• 10:24
  Speaker 1: a black.
• 10:24
  Speaker 2: Hole, right Like, you need to have a certain amount
• 10:28
  Speaker 2: of mass to your star for it to even have
• 10:30
  Speaker 2: a chance at becoming a black hole.
• 10:32
  Speaker 1: Exactly, because there are other forces that can push back
• 10:34
  Speaker 1: against gravity, Like you can make something really really dense,
• 10:37
  Speaker 1: like a neutron star, which you can have like the
• 10:40
  Speaker 1: mass of the Sun with a small radius of just kilometers,
• 10:43
  Speaker 1: and even that is very dense, has a lot of gravity,
• 10:46
  Speaker 1: but there are nuclear forces there. The strong nuclear force
• 10:49
  Speaker 1: is pushing back and preventing it from collapsing into a
• 10:51
  Speaker 1: black hole. So even if you don't have fusion pressure
• 10:54
  Speaker 1: from an active star, you can still avoid collapsing into
• 10:57
  Speaker 1: a black hole just from the chemical forces or the
• 11:00
  Speaker 1: strong nuclear forces.
• 11:01
  Speaker 2: Right now, Violet's question was about our sun. She's wondering
• 11:05
  Speaker 2: if our sun will one day collapse into a black hole,
• 11:08
  Speaker 2: and so what's the answer, yes or no.
• 11:09
  Speaker 1: The answer is almost certainly no, but there is still
• 11:12
  Speaker 1: a lot of uncertainty in exactly how much mass you need.
• 11:16
  Speaker 1: As you said, if you have enough mass, then you
• 11:18
  Speaker 1: have enough gravity. You can overcome all of these forces eventually,
• 11:21
  Speaker 1: the fusion force and the strong nuclear force, and you
• 11:24
  Speaker 1: can collapse into a black hole. But we think that
• 11:26
  Speaker 1: the threshold is somewhere around ten times the mass of
• 11:29
  Speaker 1: the Sun, though it's not something we understand in great detail,
• 11:33
  Speaker 1: and the sort of the consensus number has been moving
• 11:35
  Speaker 1: around a lot.
• 11:36
  Speaker 2: Wait, what you mean, We don't know for sure if
• 11:38
  Speaker 2: our Sun is going to collapse into a black hole.
• 11:41
  Speaker 1: We don't know absolutely for sure, but it's very very unlikely.
• 11:45
  Speaker 1: The smallest black hole we've ever seen is just over
• 11:48
  Speaker 1: three times the mass of the Sun, and it probably
• 11:50
  Speaker 1: came from a star that was more like ten or
• 11:53
  Speaker 1: fifteen times the mass of the Sun. Some calculations say
• 11:56
  Speaker 1: you have to have twenty twenty five times the mass
• 11:58
  Speaker 1: of the Sun. But by looking at black hole mergers,
• 12:00
  Speaker 1: we learned a lot about the sort of minimum black
• 12:02
  Speaker 1: hole mass. It's a lot of interesting stuff still to
• 12:05
  Speaker 1: be learned about this question. But Violet, don't worry.
• 12:08
  Speaker 2: We think our Sun is safe, which means we're safe
• 12:10
  Speaker 2: and she's safe.
• 12:12
  Speaker 1: Although, of course, even though the Sun won't turn into
• 12:14
  Speaker 1: a black hole, that doesn't mean it'll be a fun
• 12:16
  Speaker 1: place to live in about five billion years when it
• 12:19
  Speaker 1: expands into a red super giant and fries the.
• 12:21
  Speaker 2: Earth boy, wait to setter at ease. There, we we
• 12:25
  Speaker 2: just ask her a question and she's like phew, and
• 12:28
  Speaker 2: then you drop the bond.
• 12:30
  Speaker 1: Well, you know, budding astrophysicists got to learn that the
• 12:33
  Speaker 1: universe is a scary place.
• 12:35
  Speaker 2: But the basic answer for Violet is that our Sun
• 12:37
  Speaker 2: doesn't have enough mass, we think, to ever collapse into
• 12:40
  Speaker 2: a black hole. So what's going to happen to our
• 12:42
  Speaker 2: Sun is just going to keep burning forever.
• 12:43
  Speaker 1: It's not going to burn forever. A lot of helium
• 12:45
  Speaker 1: will accumulate its core, which will move the burning more
• 12:48
  Speaker 1: to the exterior, which will puff up the Sun, so
• 12:51
  Speaker 1: it'll grow to be a super giant, a big red star.
• 12:54
  Speaker 1: Then will blow off its outer layers and they'll leave
• 12:56
  Speaker 1: behind a hot core. So probably the Sun will become
• 13:00
  Speaker 1: a white dwarf, which basically just means it leaves behind
• 13:03
  Speaker 1: a big blob of hot metal.
• 13:05
  Speaker 2: It'll just be sort of like a big ball of
• 13:07
  Speaker 2: metal glowing in the dark.
• 13:09
  Speaker 1: Yeah, exactly.
• 13:10
  Speaker 2: Well, hopefully by then a Violet will have invented a
• 13:13
  Speaker 2: warp drive or something, or a wormhole maybe, because Violet
• 13:17
  Speaker 2: sounds pretty smart. And by then we'll be expanding into
• 13:21
  Speaker 2: other solar systems.
• 13:22
  Speaker 1: That's right. Our whole generation of astrophysicists inspired by your
• 13:25
  Speaker 1: book will save humanity. Yeah.
• 13:28
  Speaker 2: And then I'll get all the credit right.
• 13:31
  Speaker 1: And the royalties, right, you get some of those patents right?
• 13:35
  Speaker 2: Yes, I'm going to say yes, and then have the
• 13:38
  Speaker 2: lawyers figure it out. All right. Well, let's get to
• 13:40
  Speaker 2: more questions from kids about this great big universe. But
• 13:44
  Speaker 2: first let's take a quick great or right. We're answering
• 14:00
  Speaker 2: kids questions here today about the universe to celebrate the
• 14:03
  Speaker 2: release of my new book, Oliver's Great Big Universe. Now, Daniel,
• 14:06
  Speaker 2: what kinds of books did you read when you were
• 14:08
  Speaker 2: a kid? Did you read any physics books?
• 14:10
  Speaker 1: Hmmm, oh, great question. When I was eleven, I was
• 14:13
  Speaker 1: definitely reading a lot of science fiction books, and I
• 14:16
  Speaker 1: definitely watched a lot of like nova and documentaries on TV,
• 14:20
  Speaker 1: and I gobbled up like big picture books with drawings
• 14:23
  Speaker 1: with artists impressions of black holes and stuff like that.
• 14:26
  Speaker 2: Yeah, and so today, to mark the release of the book,
• 14:28
  Speaker 2: we're answering listener questions and specifically from kids. And so
• 14:32
  Speaker 2: our next question comes from James and his dead.
• 14:35
  Speaker 3: Hi, Daniel and Joge. This is Paul from Manchester in England.
• 14:40
  Speaker 3: My son James likes thinking about the implications of an
• 14:43
  Speaker 3: infinite universe. In particular, he has this idea that's in
• 14:47
  Speaker 3: an infinite universe, anything that could possibly have happened must
• 14:50
  Speaker 3: have happened an infinite number of times. He was talking
• 14:54
  Speaker 3: to me about this recently and it led me to
• 14:56
  Speaker 3: wonder whether we can say that if the universe is
• 14:59
  Speaker 3: inf it must not be possible to make a machine
• 15:03
  Speaker 3: to travel cosmic scale distances very quickly, because if it
• 15:07
  Speaker 3: was possible to build such a machine, then in an
• 15:10
  Speaker 3: infinite universe, an infinite number of alien civilizations would have
• 15:14
  Speaker 3: done it, and our planet would inevitably have been colonized
• 15:18
  Speaker 3: by aliens. James and I look forward to hearing your
• 15:21
  Speaker 3: thoughts on this. Thanks very much.
• 15:23
  Speaker 2: Oh my goodness, this kid, James should write his own book.
• 15:28
  Speaker 2: What an awesome idea. Can we just give him a
• 15:30
  Speaker 2: Nobel prize.
• 15:31
  Speaker 1: A Nobel Prize for arguing that a breakthrough is not possible.
• 15:36
  Speaker 2: And a Noble price just for blowing my mind? What
• 15:39
  Speaker 2: an interesting question.
• 15:40
  Speaker 1: Yeah, it is a really ingenious idea, all.
• 15:44
  Speaker 2: Right, So let's break it down. So I think James
• 15:46
  Speaker 2: is saying that if faster than light travel was possible
• 15:50
  Speaker 2: and the universe is infinite, then by now some alien
• 15:55
  Speaker 2: civilization with faster than light travel should have visited us.
• 15:58
  Speaker 1: But by now, yeah, I think think that's the argument.
• 16:00
  Speaker 1: It's sort of similar to saying, if time travel is possible,
• 16:04
  Speaker 1: somebody in the future would have discovered it and then
• 16:07
  Speaker 1: come back to visit us, and so since they haven't,
• 16:09
  Speaker 1: therefore time travel is not possible. Except in this case,
• 16:12
  Speaker 1: he's reflecting that argument into space and imagining somebody out
• 16:16
  Speaker 1: there must have figured out faster than light travel and
• 16:19
  Speaker 1: if they had, they would have come visited us, and
• 16:21
  Speaker 1: they haven't, so therefore maybe it's impossible.
• 16:23
  Speaker 2: Right. What do you call that kind of argument? Is
• 16:26
  Speaker 2: there a name for it?
• 16:27
  Speaker 1: Clever? Clever argument from desperation?
• 16:31
  Speaker 2: I don't know, And I've heard this argument before, like
• 16:35
  Speaker 2: there's no time travel because otherwise there would be time
• 16:38
  Speaker 2: travelers visiting us right now. But I always feel like
• 16:41
  Speaker 2: that's assuming we live in an interesting time.
• 16:44
  Speaker 1: But if there's an infinite future for humanity, then somebody
• 16:47
  Speaker 1: will find us interesting.
• 16:48
  Speaker 2: Right well, I feel like it's sort of like if
• 16:50
  Speaker 2: you're in a really bad place and you're like, there
• 16:52
  Speaker 2: must not be any tourists in the world, because we
• 16:55
  Speaker 2: never get tourists here. That's really just says something about
• 16:59
  Speaker 2: where you live.
• 17:00
  Speaker 1: But if there were an infinite number of tourists, somebody
• 17:02
  Speaker 1: would think that your boring street was fascinating. I think
• 17:06
  Speaker 1: that's the crux of his argument. It really relies on
• 17:08
  Speaker 1: this idea of infinity. In the power of infinity.
• 17:12
  Speaker 2: Right right, unless your plate you live in an infinitely
• 17:14
  Speaker 2: boring place, in case it cancels out, what's infinitely divided
• 17:18
  Speaker 2: by infinity.
• 17:19
  Speaker 1: Theologians have been thinking about infinitely powerful forces and infinitely
• 17:22
  Speaker 1: strong walls, but you're thinking about infinitely boring places and
• 17:26
  Speaker 1: infinite numbers of tourists.
• 17:28
  Speaker 2: Yeah, you know, that's what this podcast is all about,
• 17:31
  Speaker 2: great big ideas.
• 17:33
  Speaker 1: That's right. Well, there's a lot of really interesting ideas
• 17:36
  Speaker 1: in James's argument. The first one is essentially that if
• 17:39
  Speaker 1: the universe is infinite. Anything that can happen will happen,
• 17:44
  Speaker 1: and that's how we get the idea that if fast
• 17:46
  Speaker 1: and light travel is possible, somebody out there will develop it.
• 17:49
  Speaker 1: And that's a subtle idea.
• 17:51
  Speaker 2: Actually, it's pretty interesting, right to think there might be
• 17:54
  Speaker 2: an infinite number of alien civilizations, and if it was possible,
• 17:57
  Speaker 2: one of them must surely have invented war price.
• 18:00
  Speaker 1: Yeah, and if you take it literally, it doesn't just
• 18:02
  Speaker 1: imply an infinite number of alien civilizations and implies an
• 18:05
  Speaker 1: infinite number of human civilizations, right, because if humanity can evolve,
• 18:10
  Speaker 1: which obviously it can because it has and space is infinite,
• 18:14
  Speaker 1: that would suggest that it's happening somewhere else actually an
• 18:17
  Speaker 1: infinite number of times.
• 18:19
  Speaker 2: But do they have to be humans? Couldn't they be
• 18:21
  Speaker 2: like tentacled aliens that invent the warp drive?
• 18:24
  Speaker 1: No, they don't have to be humans. I think it's
• 18:26
  Speaker 1: actually weirder if there are more humans out there totally
• 18:29
  Speaker 1: independently evolved than like weirdly tentacled aliens.
• 18:32
  Speaker 2: Although technically, in an infinite universe, wouldn't you also get
• 18:35
  Speaker 2: an infinite number of human civilizations?
• 18:38
  Speaker 1: Yeah? Exactly, you get an infinite number of everything that's possible.
• 18:41
  Speaker 2: And virtually possible because we're here.
• 18:43
  Speaker 1: Yeah, exactly, So you would have an infinite number of
• 18:46
  Speaker 1: James Is asking an infant number of questions on an
• 18:48
  Speaker 1: infinite number of podcasts.
• 18:52
  Speaker 2: All right, So then how would you answer that or
• 18:54
  Speaker 2: how would you break down the infinity argument.
• 18:56
  Speaker 1: I think it's a pretty strong argument, but there are
• 18:58
  Speaker 1: some holes. Here's some nuances, and one is on the
• 19:01
  Speaker 1: issue of infinity. It's true that anything with a finite
• 19:04
  Speaker 1: probability will happen an infinite number of times if you
• 19:07
  Speaker 1: get an infinite number of tries, Like if you have
• 19:09
  Speaker 1: some huge die with a billion sides to it, it
• 19:12
  Speaker 1: doesn't really matter how many billion sides there are. If
• 19:15
  Speaker 1: you get to roll an infinite number of times, eventually
• 19:18
  Speaker 1: every side will come up. So that part is true.
• 19:21
  Speaker 1: But when you apply that to anything could happen in
• 19:23
  Speaker 1: the universe, there's a little wrinkle there, which is that
• 19:26
  Speaker 1: you need the right initial conditions. Imagine an infinite universe,
• 19:30
  Speaker 1: for example, that's just smooth and has no features, no
• 19:33
  Speaker 1: structure to it, no stars ever form, no galaxies ever form.
• 19:37
  Speaker 1: That's an infinite universe. But you don't get every outcome,
• 19:40
  Speaker 1: because the outcomes are determined by the initial conditions. You
• 19:43
  Speaker 1: have to have like the right configuration for things to
• 19:45
  Speaker 1: start from, which determines essentially what is possible.
• 19:49
  Speaker 2: Yeah, I guess you have to assume that the rest
• 19:51
  Speaker 2: of the infinite universe is just like the universe that
• 19:54
  Speaker 2: we see around us, which may not be the case.
• 19:56
  Speaker 1: Which may not be the case exactly, But you could
• 19:58
  Speaker 1: also imagine that maybe in order to develop faster than
• 20:02
  Speaker 1: like travel, some alien civilization needs a very different set
• 20:05
  Speaker 1: of conditions than the kind we have here. You're much
• 20:08
  Speaker 1: stronger curvature, So these aliens grow up with a native
• 20:11
  Speaker 1: understanding of space time and can therefore manipulate it. Maybe
• 20:15
  Speaker 1: they need to be like a planet inside a black hole. Right,
• 20:18
  Speaker 1: It's possible inside super massive black holes to have stable
• 20:22
  Speaker 1: orbits and people are speculated you could have life evolve
• 20:24
  Speaker 1: inside of it. But a species that evolves inside a
• 20:27
  Speaker 1: black hole, they couldn't even use their FTL travel to
• 20:30
  Speaker 1: reach us.
• 20:31
  Speaker 2: WHOA, But I think that doesn't affect James's question, right,
• 20:35
  Speaker 2: Like we know that the conditions surround us are possible.
• 20:37
  Speaker 1: I think it's true that if the universe is infinite
• 20:39
  Speaker 1: and filled with infinite stuff. There's an infinite number of
• 20:42
  Speaker 1: human civilizations and maybe also infinite alien civilizations. But it
• 20:46
  Speaker 1: might be that FTL travel is possible, is allowed by
• 20:48
  Speaker 1: the laws of physics, but that none of the infinite
• 20:51
  Speaker 1: number of human civilizations discover it either, because the conditions
• 20:54
  Speaker 1: in which we grow up, in which we evolve don't
• 20:57
  Speaker 1: give us a sort of natural intuition to manipulate space time,
• 21:01
  Speaker 1: because we're like not near enough black holes to experience that.
• 21:04
  Speaker 2: Well, But isn't that a bit of a stretch of
• 21:06
  Speaker 2: an argument. I mean, we can still discover it. We
• 21:08
  Speaker 2: don't have to be living inside of a black hole
• 21:10
  Speaker 2: for us right now to understand what it's like to
• 21:13
  Speaker 2: live in a black hole.
• 21:14
  Speaker 1: Yeah, that's right. It's possible that we could in the
• 21:15
  Speaker 1: future discover FTL travel. My point is essentially that there's
• 21:19
  Speaker 1: some limitations to the possible outcomes. You have an infinite
• 21:22
  Speaker 1: number of roles that die, but the die might have
• 21:24
  Speaker 1: some limitations on those possible outcomes based on the configuration
• 21:28
  Speaker 1: of space. Not everything that is possible actually does happen,
• 21:32
  Speaker 1: only things that are possible, and that our potential outcomes
• 21:35
  Speaker 1: from the initial conditions of the universe, like For example,
• 21:39
  Speaker 1: having the entire universe collapse into a black hole physically
• 21:43
  Speaker 1: possible is something against the laws of physics from that configuration,
• 21:46
  Speaker 1: but you can't get to that configuration from here. There's
• 21:49
  Speaker 1: lots of things between you and that arrangement of stuff
• 21:52
  Speaker 1: in the universe. So not every arrangement that's physically possible
• 21:56
  Speaker 1: will actually be realized by our universe because we start
• 21:59
  Speaker 1: from a certain configuration.
• 22:01
  Speaker 2: But then in an infinite universe, don't you get all
• 22:03
  Speaker 2: infinite possible starting conditions?
• 22:06
  Speaker 1: Yes, great question. We don't know, right because we don't
• 22:08
  Speaker 1: really understand the starting configurations of our universe. We know
• 22:12
  Speaker 1: that we had a fairly smooth universe with some quantum fluctuations,
• 22:15
  Speaker 1: we don't really know exactly where those came from and
• 22:18
  Speaker 1: what came before that, so we don't know if we've
• 22:20
  Speaker 1: like really explored the full range of possible initial configurations,
• 22:25
  Speaker 1: or if we're only getting a little slice, or maybe
• 22:28
  Speaker 1: elsewhere in the universe they got different initial configurations. We
• 22:31
  Speaker 1: just don't know.
• 22:32
  Speaker 2: I guess I think James is saying, if it is
• 22:34
  Speaker 2: possible for humans at least to come up with faster
• 22:38
  Speaker 2: than light travel, then if there are infinite number of
• 22:40
  Speaker 2: humans out there, then they must have surely discovered it.
• 22:43
  Speaker 2: Just because it's maybe more likely for black hole aliens
• 22:46
  Speaker 2: to discover it doesn't mean that we can't discover it
• 22:48
  Speaker 2: or that it's not possible, right, because it's the same
• 22:50
  Speaker 2: loss of physics, isn't it.
• 22:51
  Speaker 1: Yeah, that's right. If it's possible for humans to discover
• 22:54
  Speaker 1: FTL travel, then I think you're right. In an infinite
• 22:57
  Speaker 1: universe they will. But there's a difference between is FTL
• 23:00
  Speaker 1: travel allowed by the laws of physics and is it
• 23:03
  Speaker 1: possible for humans to discover it. Another possibility is the
• 23:06
  Speaker 1: universe allows faster than light travel by some crazy warped technology,
• 23:10
  Speaker 1: but humans are just not smart enough to figure it out.
• 23:13
  Speaker 1: That it's not discoverable by us and any of our
• 23:17
  Speaker 1: infinite brethren because it just requires like much more mental
• 23:20
  Speaker 1: computing power than we're capable of.
• 23:22
  Speaker 2: Hmm. But that's why we build the eyes.
• 23:26
  Speaker 1: Yeah, that's a great point. So like machine augmented human
• 23:30
  Speaker 1: intelligence might not have the same kind of limitations, So
• 23:34
  Speaker 1: that's a way around that argument. So yeah, it's a
• 23:36
  Speaker 1: really interesting, I think, quite powerful argument. There are a
• 23:39
  Speaker 1: few nuances and subtleties there, but I think he's right
• 23:41
  Speaker 1: that we can say a lot about the likelihood of
• 23:44
  Speaker 1: FTL travel from the fact that we haven't been visited.
• 23:46
  Speaker 1: Or maybe you're right and our corner of Earth is just.
• 23:49
  Speaker 2: Too boring, infinitely boring. Well, I think the other big
• 23:53
  Speaker 2: limitation is just time, Like, maybe you need more time
• 23:56
  Speaker 2: for any of these infinitializations to come up faster than
• 24:00
  Speaker 2: light travel, and maybe the universe is just not old enough.
• 24:03
  Speaker 2: You sort of also need infinite time, right.
• 24:05
  Speaker 1: You definitely need time, but how much time you need
• 24:07
  Speaker 1: depends a little bit on like how fast this faster
• 24:10
  Speaker 1: than light travel is. If you can go anywhere in
• 24:13
  Speaker 1: the universe in a moment, like with a wormhole, then
• 24:15
  Speaker 1: you're really visitable from anywhere in the infinite universe. And
• 24:19
  Speaker 1: you know, the universe is pretty old. Fourteen billion years
• 24:22
  Speaker 1: is a long time. We're sort of late in the
• 24:25
  Speaker 1: era of the universe. Our solar system has only been
• 24:27
  Speaker 1: around for a few billion years. So in an infinite universe,
• 24:31
  Speaker 1: there will have been civilizations that started billions and billions
• 24:34
  Speaker 1: of years ago and certainly have had time to reach us.
• 24:37
  Speaker 2: Yeah, or maybe not right, Like, maybe you need more time, right,
• 24:40
  Speaker 2: And the other thing I was thinking about is that
• 24:42
  Speaker 2: if it is an infinite universe, that means there are
• 24:44
  Speaker 2: an infinite number of places you can go, which means
• 24:48
  Speaker 2: like the likelihood that some an alien civilization with faster
• 24:51
  Speaker 2: than light travel would come to our planet is almost
• 24:54
  Speaker 2: like infinitely small, too, isn't it.
• 24:56
  Speaker 1: Yeah, there's a lot of infinities here. You tackle a
• 24:58
  Speaker 1: lot of similar ideas when you think just about the
• 25:00
  Speaker 1: more standard Fermi paradox, like the galaxy is pretty old
• 25:04
  Speaker 1: and not that big, why haven't we been visited even
• 25:07
  Speaker 1: without FTL travel? Because it only takes like a few
• 25:10
  Speaker 1: tens of thousands of years to explore the whole galaxy,
• 25:14
  Speaker 1: either with like self replicating probes or even a small
• 25:17
  Speaker 1: fleet of ships. So I think the same math holds
• 25:19
  Speaker 1: there that an infinite universe, you should have an infinite
• 25:22
  Speaker 1: number of aliens with FTL travel, and eventually some of
• 25:25
  Speaker 1: them should reach us. And given how old the universe is,
• 25:28
  Speaker 1: it is a little odd that we haven't been visited.
• 25:30
  Speaker 2: Yeah, And the other counter argument to James's idea here,
• 25:33
  Speaker 2: I feel like it's like, how do you know we
• 25:35
  Speaker 2: haven't been visited by aliens with faster than like travel?
• 25:38
  Speaker 2: You know, like, how do you know I'm not a
• 25:40
  Speaker 2: time traveler from the future.
• 25:41
  Speaker 3: Mmm.
• 25:42
  Speaker 1: Or maybe James is actually an alien and this is
• 25:45
  Speaker 1: his way to sort of introduce subtly the concept into
• 25:48
  Speaker 1: the zeitgeist.
• 25:49
  Speaker 2: I see, maybe he's an alien and a time traveler.
• 25:52
  Speaker 2: Maybe he's an alien from the future.
• 25:55
  Speaker 1: James, if you're visiting alien or visiting human from somewhere
• 25:58
  Speaker 1: else farw in the universe, I hope you don't find
• 26:00
  Speaker 1: us too boring.
• 26:01
  Speaker 2: Yeah, I hope he finds us only finitely. All right, Well,
• 26:06
  Speaker 2: let's get to more questions from kid listeners. But first
• 26:08
  Speaker 2: let's take another quick break. All right, we're answering questions
• 26:24
  Speaker 2: from kids to celebrate the release of my new book,
• 26:26
  Speaker 2: Oliver's Great Big Universe. Let's get to our last questions
• 26:29
  Speaker 2: here from kid listeners. The next one comes from Ida hy.
• 26:33
  Speaker 1: Daniel Josh, Would I had special pal inside of black hole?
• 26:42
  Speaker 2: Awesome question. I'm going to say the answer is yes.
• 26:45
  Speaker 1: Next question, you are the superhero science expert on the podcast.
• 26:50
  Speaker 1: You know what kind of special powers would you get
• 26:52
  Speaker 1: from being inside a black hole?
• 26:53
  Speaker 2: Oh? Boy, I feel like I could write a whole
• 26:56
  Speaker 2: other book about this idea.
• 26:59
  Speaker 1: Sounds like you and Ida should write that book.
• 27:02
  Speaker 2: Itida's great big black hole. Well, then let's see her question.
• 27:06
  Speaker 2: Let's break it down. She asked, would she have special
• 27:09
  Speaker 2: powers if she was inside a black hole?
• 27:12
  Speaker 1: Do you think this is sort of like a bitten
• 27:14
  Speaker 1: by a radioactive spider kind of situation?
• 27:16
  Speaker 2: Or maybe I think she's saying like, if she lived
• 27:18
  Speaker 2: inside of a black hole, would life be the same
• 27:21
  Speaker 2: for her? Or would she be able to do things
• 27:23
  Speaker 2: she couldn't do outside of the black hole?
• 27:25
  Speaker 1: Yeah? I see, Well, there is one way in which
• 27:28
  Speaker 1: being inside a black hole would be pretty different from
• 27:31
  Speaker 1: living on Earth, and that has to do with the
• 27:33
  Speaker 1: flow of time. Right. We know that time goes slower
• 27:36
  Speaker 1: when space is curved, the same way that space is curved.
• 27:39
  Speaker 1: Near mass's time is essentially also curved. Space and time
• 27:43
  Speaker 1: curved together. What that means is, if you're near something really,
• 27:46
  Speaker 1: really massive, your time goes slower. Like somebody far out
• 27:50
  Speaker 1: in space, their time goes faster than somebody standing on
• 27:53
  Speaker 1: Earth and near a black hole or inside a black hole,
• 27:56
  Speaker 1: time goes super duper slow.
• 27:59
  Speaker 2: How slow to zero.
• 28:00
  Speaker 1: It depends a little on the observer. But if you're
• 28:02
  Speaker 1: far away from a black hole and you see somebody
• 28:05
  Speaker 1: falling into a black hole. You will see their time
• 28:07
  Speaker 1: go slower and slower, so that you'll never actually even
• 28:10
  Speaker 1: see them cross over into the black hole because their
• 28:12
  Speaker 1: time will slow down so much. They'll sort of asymptotically
• 28:16
  Speaker 1: approach the black hole from their point of view. They
• 28:18
  Speaker 1: will fall in the black hole, and they will see
• 28:21
  Speaker 1: your clocks speed up by how much depends on the
• 28:24
  Speaker 1: mass of the black hole that you're falling into.
• 28:27
  Speaker 2: I see. So the power you get by falling into
• 28:29
  Speaker 2: a black hole is you get to fast forward the
• 28:31
  Speaker 2: rest of the universe.
• 28:32
  Speaker 1: Yeah, you get to fast forward the rest of the universe.
• 28:34
  Speaker 2: Like if it's infinitely boring, you can just be like.
• 28:36
  Speaker 1: Skip exactly that button that says like skip intro or skip.
• 28:42
  Speaker 2: Recap, skip everything. I just want to see the credits.
• 28:47
  Speaker 1: Exactly, skip forward to see the credits. And so you'll
• 28:50
  Speaker 1: see the rest of the universe going in fast forward.
• 28:53
  Speaker 1: You'll see like the end of our star. You'll see
• 28:55
  Speaker 1: the collision of our galaxy with other galaxies. All this
• 28:58
  Speaker 1: kind of stuff will happen. Now actually see it all
• 29:00
  Speaker 1: through just a tiny little pinprick, because if you're actually
• 29:03
  Speaker 1: within an event horizon of a black hole, all the
• 29:05
  Speaker 1: light in the universe still comes to you, but it
• 29:07
  Speaker 1: comes to you through this tiny little dot. Most of
• 29:10
  Speaker 1: space is so bent that everything in front of you
• 29:12
  Speaker 1: is just the singularity, but there'll be this tiny little
• 29:15
  Speaker 1: dot behind you where photons can still make it to
• 29:18
  Speaker 1: you and bring you news of the universe you fast forwarded.
• 29:22
  Speaker 2: Well. First of all, as we've talked about it before,
• 29:24
  Speaker 2: it is possible to go into a black hole, right Like,
• 29:27
  Speaker 2: if a black hole is big enough, then its event
• 29:30
  Speaker 2: horizon is at a point where you wouldn't necessarily get
• 29:33
  Speaker 2: shredded by the gravitational forces. It is possible for someone
• 29:37
  Speaker 2: like you and me to go into a black hole.
• 29:38
  Speaker 1: Yeah, And as we talked about in our recent book,
• 29:40
  Speaker 1: frequently asked questions about the universe, As you get closer
• 29:43
  Speaker 1: and closer, the event horizon swells to take up a
• 29:46
  Speaker 1: larger and larger portion of your view, eventually takes up
• 29:49
  Speaker 1: like half of your view, and then it grows around
• 29:51
  Speaker 1: you and then you can only see a tiny little dot.
• 29:53
  Speaker 2: But then you could potentially still be conscious and be
• 29:56
  Speaker 2: thinking about and experiencing this phenomenon, right like, you'd be
• 30:00
  Speaker 2: oh my god, what's going on now? Ida's question is,
• 30:02
  Speaker 2: would you have superpowers.
• 30:06
  Speaker 1: I think fast forwarding to the end of the universe
• 30:07
  Speaker 1: feels like a special power. It's not a superpower in
• 30:10
  Speaker 1: the sense that it's not like supernatural doesn't break the
• 30:13
  Speaker 1: laws of physics, But I think what physics can do
• 30:15
  Speaker 1: is pretty special, so I think it counts as a
• 30:17
  Speaker 1: special power even if it's not a superpower.
• 30:20
  Speaker 2: I guess, like if you fell into a black hole,
• 30:23
  Speaker 2: then you survive, your body wouldn't necessarily change, so you
• 30:25
  Speaker 2: wouldn't get the superpowers necessarily. But I wonder if maybe
• 30:28
  Speaker 2: Ida's wondering, like, you know, like if you go to
• 30:30
  Speaker 2: the moon or moon here, you could jump really high,
• 30:33
  Speaker 2: for example, because there's less gravity. Would there be any
• 30:36
  Speaker 2: kind of things I could do in a black hole
• 30:38
  Speaker 2: I couldn't normally do.
• 30:39
  Speaker 1: I think in a black hole you'd never have to
• 30:41
  Speaker 1: worry about cleaning up. You could just throw stuff into
• 30:43
  Speaker 1: the singularity. You basically never have to take out the trash.
• 30:46
  Speaker 2: Yeah, that's a superpower for sure. I'm not sure that
• 30:50
  Speaker 2: they'll let you into any adventurous team or anything like that. Yeah,
• 30:54
  Speaker 2: but you know, you said earlier that it is possible
• 30:56
  Speaker 2: maybe for there to be planets inside of a black hole.
• 30:59
  Speaker 2: You know, orbiting a star and stuff. Would life be
• 31:02
  Speaker 2: different for them or would it be the same as
• 31:04
  Speaker 2: it is for us.
• 31:06
  Speaker 1: Life would certainly be different for them, and you could
• 31:08
  Speaker 1: check out our podcast episode. I think Katie was our
• 31:10
  Speaker 1: co host on that one, because they would see things
• 31:13
  Speaker 1: very differently. Right, you wouldn't have any illumination, and your
• 31:16
  Speaker 1: planet would be really hot on the inside it be
• 31:18
  Speaker 1: squeezed by the tidal forces. It'd be more like living
• 31:21
  Speaker 1: on the moon of Jupiter, you know, like Io, which
• 31:24
  Speaker 1: is very volcanic, So it'd be a very different kind
• 31:26
  Speaker 1: of experience. Kids on that planet wouldn't look up at
• 31:28
  Speaker 1: the night sky and see the same things that we see.
• 31:30
  Speaker 1: They would see a completely black night sky except for
• 31:33
  Speaker 1: a tiny little dot through which they would see everything
• 31:35
  Speaker 1: else in the universe.
• 31:37
  Speaker 2: Could they see like the hand in front of them?
• 31:39
  Speaker 2: Like if I put my hand in front of me
• 31:41
  Speaker 2: inside of black hole? Could I see my hand?
• 31:43
  Speaker 1: And the outskirts of a super massive black hole. Space
• 31:46
  Speaker 1: is not so curved that you couldn't see anything, and
• 31:49
  Speaker 1: so it is possible for light to still make some
• 31:51
  Speaker 1: progress towards your eyeballs. And the outskirts of a super
• 31:54
  Speaker 1: massive black.
• 31:55
  Speaker 2: Hole, like you'd be inside, but you'd be near the edge.
• 31:58
  Speaker 2: Mm hmm, so maybe you could. You would see your hand,
• 32:01
  Speaker 2: but it would all be kind of weird and distorted.
• 32:03
  Speaker 1: All of space would be very distorted, so the way
• 32:05
  Speaker 1: time would flow would be different. People closer to the
• 32:07
  Speaker 1: center of black hole would have their clocks slow down
• 32:10
  Speaker 1: compared to people further from the center of the black hole.
• 32:13
  Speaker 1: So it'd be pretty hard, for example, to have like
• 32:14
  Speaker 1: a zoom session across the whole planet if you're living
• 32:17
  Speaker 1: inside a black hole.
• 32:18
  Speaker 2: Oh, thank goodness.
• 32:20
  Speaker 1: Great, there's your superpower. You can say no to all
• 32:24
  Speaker 1: online meetings.
• 32:25
  Speaker 2: That's right, it'd be infinitely boring, just like a regular
• 32:30
  Speaker 2: zoom meeting. All right. Well, to answer Ida's question, it
• 32:32
  Speaker 2: sounds like she wouldn't gain any special powers except the
• 32:36
  Speaker 2: ability to see the rest of the universe in fast.
• 32:38
  Speaker 1: Forward and to never have to clean your room.
• 32:40
  Speaker 2: Although I think if Ida ever makes it inside of
• 32:43
  Speaker 2: a black hole and lists to tell about it, I
• 32:45
  Speaker 2: think she would be a superhero in my book. All right.
• 32:48
  Speaker 2: Our last question comes from Joey. What are the newest
• 32:51
  Speaker 2: and the oldest black holes in the universe? What are
• 32:55
  Speaker 2: the newest and oldest black holes? In the universe. Awesome question,
• 32:59
  Speaker 2: A little we knowsy if.
• 33:01
  Speaker 1: You ask me, you don't think he deserves to know.
• 33:07
  Speaker 2: I'm saying, if you go around asking people's age, you know,
• 33:10
  Speaker 2: you might get some curd answers.
• 33:13
  Speaker 1: No. I think the biggest, oldest black holes in the
• 33:15
  Speaker 1: universe are probably proud of their status. You know, they're
• 33:18
  Speaker 1: like silver backs tramping around in the jungles at the
• 33:21
  Speaker 1: hearts of galaxies.
• 33:23
  Speaker 2: Mmmm. I see, Yeah, they're like the alpha black holes
• 33:26
  Speaker 2: that we're.
• 33:27
  Speaker 1: Saying, yeah, the ogs exactly.
• 33:29
  Speaker 2: All right, Well, this is an interesting question because we
• 33:32
  Speaker 2: know that black holes form very early on in the universe,
• 33:36
  Speaker 2: and we know that black holes are forming all the
• 33:38
  Speaker 2: time right now. So you know, I wonder if his
• 33:41
  Speaker 2: question is what are the oldest and newest black holes
• 33:43
  Speaker 2: we know about? Or what are the oldest and newest
• 33:47
  Speaker 2: black holes that exist in the universe.
• 33:49
  Speaker 1: Yeah, right, Both of those are good questions. In the
• 33:51
  Speaker 1: case of the oldest black hole, we definitely don't know
• 33:54
  Speaker 1: what is the oldest black hole, or theoretically what could
• 33:57
  Speaker 1: be the oldest black hole, because there's one theory that
• 34:00
  Speaker 1: black holes are as old as the universe itself, that
• 34:04
  Speaker 1: they might even like be older than electrons, that black
• 34:07
  Speaker 1: holes could have been formed during the Big Bang.
• 34:10
  Speaker 2: Whoa wait, even before we had like quantum fields.
• 34:13
  Speaker 1: Before we had matter, before those quantum fields settled down,
• 34:16
  Speaker 1: so we could have things called electrons and protons and
• 34:19
  Speaker 1: quarks when things were still so hot and so dense
• 34:22
  Speaker 1: that talking about them in terms of those objects doesn't
• 34:25
  Speaker 1: make a lot of sense, the way you wouldn't talk
• 34:26
  Speaker 1: about a wave in terms of its drops. So there's
• 34:29
  Speaker 1: this theory of primordial black holes that suggest that very
• 34:32
  Speaker 1: hot patches of the universe might have collapsed into black
• 34:35
  Speaker 1: holes even before matter was formed, and those black holes
• 34:38
  Speaker 1: might still be around.
• 34:40
  Speaker 2: Mm they wouldn't have evaporated by now or right because
• 34:44
  Speaker 2: black holes that don't die very easily.
• 34:46
  Speaker 1: Some of the black holes would definitely have evaporated. The
• 34:48
  Speaker 1: bigger black holes evaporate more slowly, and smaller black holes
• 34:51
  Speaker 1: evaporate quickly, so we would expect it some of them
• 34:53
  Speaker 1: to have evaporated and some of them to still be around,
• 34:56
  Speaker 1: and some of them to be evaporating right now. So
• 34:59
  Speaker 1: if the scenari is true, we should be able to
• 35:01
  Speaker 1: see these primordial black holes like evaporating all the time.
• 35:05
  Speaker 2: So maybe the oldest black hole in the universe was
• 35:07
  Speaker 2: there from the beginning, from the beginning of the universe.
• 35:10
  Speaker 1: It's possible. It's even this fun theory that this impact
• 35:13
  Speaker 1: inside Burea about one hundred years ago, which mysteriously left
• 35:16
  Speaker 1: no crater, was actually a primordial black hole that took
• 35:20
  Speaker 1: like a core sample of the Earth instead of an
• 35:22
  Speaker 1: actual medior.
• 35:23
  Speaker 2: WHOA, Well, we should do an episode about that.
• 35:28
  Speaker 1: We should. The problem with primordial black holes is again,
• 35:31
  Speaker 1: if they were created, we should see them evaporating all
• 35:34
  Speaker 1: the time, and we haven't ever seen one. We've looked
• 35:36
  Speaker 1: for evidence of black holes evaporating very bright flashes of
• 35:39
  Speaker 1: Hawking radiation, but haven't seen any. So it's a possibility
• 35:43
  Speaker 1: that there are black holes as old as the universe,
• 35:46
  Speaker 1: but it's still just theoretical. But we have seen some
• 35:48
  Speaker 1: very very old black holes, like actually seeing them.
• 35:51
  Speaker 2: So then what's the oldest black hole we know about?
• 35:54
  Speaker 1: The oldest black hole we've ever seen was formed around
• 35:57
  Speaker 1: five hundred million years after the Big Bang. It was
• 36:00
  Speaker 1: seen by the games web Space telescope. It's super duper
• 36:03
  Speaker 1: far away, which is why we can see so far
• 36:06
  Speaker 1: back in time. Remember, light takes time to get here
• 36:09
  Speaker 1: and so the further things are, the further we're looking
• 36:11
  Speaker 1: back in time. So we're seeing this black hole which
• 36:13
  Speaker 1: formed just a few hundred million years after the Big Bang.
• 36:16
  Speaker 1: It's called sears ceers one zero one nine.
• 36:21
  Speaker 2: Well, what that means that it's like thirteen fourteen billion
• 36:24
  Speaker 2: years old.
• 36:24
  Speaker 1: That's exactly right. It's between thirteen and fourteen billion years old,
• 36:28
  Speaker 1: which is pretty old. At the time the light left it,
• 36:30
  Speaker 1: it only had about nine million solar masses, which is
• 36:34
  Speaker 1: much smaller than some other super massive black holes which
• 36:37
  Speaker 1: have grown to like billions of solar masses. In the meantime,
• 36:40
  Speaker 1: of course, it might have grown the light we're seeing
• 36:42
  Speaker 1: is very out of date.
• 36:43
  Speaker 2: Or it might have disappeared. Right, we don't actually know
• 36:47
  Speaker 2: it's the oldest black hole. We just know that it
• 36:49
  Speaker 2: was around a long time ago. But by now it
• 36:52
  Speaker 2: could have maybe disappeared or evaporated. Isn't it possible?
• 36:55
  Speaker 1: It's possible. You're right that we're not getting new information
• 36:57
  Speaker 1: about this very quickly. We'd have to waste billions if
• 37:00
  Speaker 1: years for the updates. But it's unlikely that a massive
• 37:03
  Speaker 1: black hole in a cluster of stars, which is where
• 37:05
  Speaker 1: we've seen it, would evaporate into nothing. To evaporate, it
• 37:08
  Speaker 1: really has to be isolated to not be fed at all.
• 37:11
  Speaker 1: And a black hole with nine million solar masses is
• 37:14
  Speaker 1: going to have very very faint Hawking radiation. The Hawking
• 37:17
  Speaker 1: radiation goes like inversely proportional to the mass, so very
• 37:20
  Speaker 1: low mass black holes evaporate more quickly than very high
• 37:23
  Speaker 1: mass black holes.
• 37:25
  Speaker 2: What if Ida went into that one and.
• 37:27
  Speaker 1: Broke it up, that would be a superpower.
• 37:30
  Speaker 2: Yeah, maybe that Maybe she didn't get superpowers when she
• 37:32
  Speaker 2: went in. All right, So that's the oldest black hole
• 37:35
  Speaker 2: we know about. What are the youngest black holes we
• 37:38
  Speaker 2: know about?
• 37:38
  Speaker 1: The youngest black hole in the universe is certainly one
• 37:40
  Speaker 1: that was created right now, and then another one created
• 37:43
  Speaker 1: right now. I mean, they're happening all the time. We
• 37:46
  Speaker 1: know that supernovas, which are typical precursors for black holes,
• 37:49
  Speaker 1: happen like every fifty years in our galaxy. But you know,
• 37:52
  Speaker 1: there's trillions of galaxies out there, so there's almost certainly
• 37:55
  Speaker 1: a black hole being formed as we speak. And by
• 37:58
  Speaker 1: the time you listen to this podcast that will be
• 37:59
  Speaker 1: out date, the'll be a new black hole formed that's
• 38:02
  Speaker 1: even more recent. So the youngest black hole in the
• 38:04
  Speaker 1: universe is definitely one that was just formed.
• 38:07
  Speaker 2: They're probably forming all the time right now, right, especially
• 38:11
  Speaker 2: if it's an infinite universe, there's an infinite number of
• 38:14
  Speaker 2: black holes being born right now.
• 38:15
  Speaker 1: Yeah, that's exactly right. So the youngest black hole is
• 38:18
  Speaker 1: constantly being replaced by some new baby black hole.
• 38:21
  Speaker 2: But what about the youngest one we know about?
• 38:23
  Speaker 1: So the youngest black hole that we have seen is
• 38:25
  Speaker 1: called W forty nine B. It's about twenty six thousand
• 38:29
  Speaker 1: light years away from Earth, and we know it's about
• 38:31
  Speaker 1: twenty seven thousand years old because the light from it
• 38:35
  Speaker 1: indicates that what we're seeing is a black hole that's
• 38:37
  Speaker 1: about a thousand years old. So we're looking at the
• 38:39
  Speaker 1: remnants of a supernova collapse that formed a black hole
• 38:43
  Speaker 1: about twenty seven thousand years ago twenty six thousand light
• 38:46
  Speaker 1: years away. So to us, it looks a thousand years old.
• 38:49
  Speaker 2: But wait, wait, wait, how do we know it's age.
• 38:51
  Speaker 2: We can tell it's aged from the light we get
• 38:53
  Speaker 2: from it, or we just saw the supernova and assume
• 38:55
  Speaker 2: that a black hole formed inside of it.
• 38:57
  Speaker 1: Yeah, great question this one. We can actually do the
• 39:00
  Speaker 1: history of it just by running the clock backwards. We
• 39:02
  Speaker 1: look at the distribution of iron and sulfur and silicon
• 39:06
  Speaker 1: in the remnant, and we can tell what happened and
• 39:08
  Speaker 1: how long it's been drifting. So we can run our
• 39:11
  Speaker 1: clock backwards essentially and say, oh, this is about a
• 39:13
  Speaker 1: thousand years old, the same way you could look at
• 39:15
  Speaker 1: a mushroom cloud from a nuclear bomb. You could tell
• 39:18
  Speaker 1: when it went off.
• 39:19
  Speaker 2: And you can actually see the black hole in the middle. Like,
• 39:22
  Speaker 2: but I thought we could only see black holes if
• 39:24
  Speaker 2: there was like if it was like a quasar or something.
• 39:26
  Speaker 1: Yeah, you're right. We can't see the black hole directly
• 39:29
  Speaker 1: because the black hole is black. We're deducing the presence
• 39:32
  Speaker 1: of the black hole from the mass of the whole
• 39:34
  Speaker 1: system and the X rays from the hot gas that
• 39:36
  Speaker 1: are nearby. And so according to our model, a black
• 39:40
  Speaker 1: hole has formed. Like what we're seeing is consistent with
• 39:43
  Speaker 1: a star that exploded and left behind a black hole.
• 39:46
  Speaker 2: All right, So then the youngest black hole that we
• 39:48
  Speaker 2: think we know about is about one thousand years old.
• 39:51
  Speaker 1: It looks a thousand years old to us, but it
• 39:53
  Speaker 1: happened twenty seven thousand years ago.
• 39:55
  Speaker 2: Mm. I mean we caught it, like we took a
• 39:57
  Speaker 2: picture of it when it was a thousand years old,
• 40:00
  Speaker 2: but the picture was taken twenty six thousand years ago exactly.
• 40:03
  Speaker 1: And to answer your other question, like, it's possible that
• 40:06
  Speaker 1: we did see this thing go supernova that like Chinese
• 40:09
  Speaker 1: astronomers a thousand years ago, we're looking up at the
• 40:11
  Speaker 1: sky and side. We do have some examples of that
• 40:13
  Speaker 1: where we see a supernova remnant, and we can find
• 40:16
  Speaker 1: in the historical record Chinese or Persian or Indian astronomers
• 40:20
  Speaker 1: writing about that supernova, which is pretty cool. Not in
• 40:23
  Speaker 1: this case, but it's possible that humans did see this
• 40:25
  Speaker 1: one blow up a thousand years ago.
• 40:27
  Speaker 2: Whoa do you think kids ask questions about it back then?
• 40:31
  Speaker 1: It's been a great, big universe for a great long time,
• 40:34
  Speaker 1: so yeah, probably.
• 40:37
  Speaker 2: All right, Well, I think that answer is Joey's question.
• 40:39
  Speaker 2: Those black holes in the universe might be the ones
• 40:41
  Speaker 2: that were formed with the universe, but we don't know
• 40:44
  Speaker 2: for sure. There is one that's at least thirteen to
• 40:47
  Speaker 2: fourteen billion years old that we know about, and there's
• 40:50
  Speaker 2: one that was born about twenty seven thousand years ago
• 40:53
  Speaker 2: that is the youngest one we know about. Although there
• 40:55
  Speaker 2: are probably definitely black holes being born all the time
• 40:58
  Speaker 2: right now, and.
• 40:58
  Speaker 1: I hope that one of those blacks is being formed
• 41:01
  Speaker 1: near some distant human civilization that's inspiring them to invent
• 41:05
  Speaker 1: faster than light travel.
• 41:06
  Speaker 2: And maybe better cleaning technology, because we could all use that.
• 41:11
  Speaker 1: And maybe give Ida special powers so that our corner
• 41:13
  Speaker 1: of the universe becomes less boring and we get more visitors.
• 41:16
  Speaker 2: I think if you take all of these kids and
• 41:18
  Speaker 2: put them into a team together to be like a
• 41:20
  Speaker 2: superhero physics team. I mean, these kids are so curious
• 41:23
  Speaker 2: and clever and smart.
• 41:24
  Speaker 1: Yeah, well, I hope that they and all the kids
• 41:26
  Speaker 1: inspired by your book do solve some of our problems
• 41:29
  Speaker 1: and change the way we understand the universe.
• 41:31
  Speaker 2: So thanks again to all of our kid question askers
• 41:35
  Speaker 2: and to all of our listeners for sending in their questions.
• 41:37
  Speaker 1: That's right, what's that website? One more time?
• 41:40
  Speaker 2: Great Big Universe dot Net. We hope you enjoyed that.
• 41:43
  Speaker 2: Thanks for joining us, See you next time.
• 41:54
  Speaker 1: Thanks for listening, and remember that. Daniel and Jorge Explain
• 41:56
  Speaker 1: the Universe is a production of iHeartRadio. More podcast from iHeartRadio,
• 42:02
  Speaker 1: visit the iHeartRadio app, Apple Podcasts, or wherever you listen
• 42:06
  Speaker 1: to your favorite shows,