Latest / Daniel and Kelly’s Extraordinary Universe / Listener Question 10: Particles, stars and universe-sized black holes!

Transcript

Listener Question 10: Particles, stars and universe-sized black holes! · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Daniel, do we get a lot of interesting questions of
0:10
Speaker 1: the podcast, you know, through email or Twitter? Oh, we
0:13
Speaker 1: get the best questions. I'll be honest. It's my favorite
0:16
Speaker 1: moment of the day when I see a new question
0:19
Speaker 1: come in from the listener line. All right, cool, So
0:21
Speaker 1: tell me how do you decide when to answer a question.
0:24
Speaker 1: Do you reply to them on the email or do
0:26
Speaker 1: you wait until we talk about it on the podcast. Well,
0:28
Speaker 1: I feel like these listeners want to know the answers.
0:31
Speaker 1: So if I know the answers, I write them right back.
0:33
Speaker 1: And if you don't, then I gotta go off and
0:35
Speaker 1: do a little bit of research. And that's how a
0:37
Speaker 1: question ends up on the podcast. I see you think
0:40
Speaker 1: I know the answer, that's right, I'll ask a real expert.
0:44
Speaker 1: It's basically, it's just a big stalling tactic when you're stumped.
0:48
Speaker 1: That's right. Listeners are very smart and if they ask
0:51
Speaker 1: me a hard enough question, it will end up on
0:53
Speaker 1: the podcast. Hi war handm cartoonists and the creator of
1:09
Speaker 1: pH D Commons. Hi. I'm Daniel. I'm a particle physicist
1:13
Speaker 1: and I've often been stumped by listener questions. Welcome to
1:16
Speaker 1: our podcast, Daniel and Jorge Explain the Universe a production
1:19
Speaker 1: of I Heart Radio in which we take you on
1:21
Speaker 1: a mental tour of the universe, all the things that
1:24
Speaker 1: science has figured out, and all the things that science
1:26
Speaker 1: is still puzzling over, all the things we know and
1:28
Speaker 1: all the things we want to know, which is basically everything,
1:31
Speaker 1: and that's right. We take you to the limits of
1:33
Speaker 1: the curiosity of scientists and also to the limits of
1:36
Speaker 1: the curiosity of our listeners. People would like you who
1:39
Speaker 1: are listening to this podcast, who have questions about the universe,
1:42
Speaker 1: about the cosmos, about our planet, and about the things
1:45
Speaker 1: that make up who we are. Because being curious, it's
1:47
Speaker 1: just part of being human. Wondering how this whole thing works,
1:50
Speaker 1: how this amazing and crazy universe came to be, how
1:53
Speaker 1: it's put together, and what its ultimate fate will be.
1:56
Speaker 1: That's just part of being human. And so we think
1:58
Speaker 1: that wondering and curio pocity belongs to everybody, and we
2:02
Speaker 1: want to bring you to the forefront of knowledge. And
2:04
Speaker 1: often we talk about the kind of questions as scientists
2:07
Speaker 1: are asking about the universe, but sometimes we talk about
2:10
Speaker 1: your question and mac question, Daniel is I'm curious about
2:12
Speaker 1: how we still have a podcast who gave a couple
2:15
Speaker 1: of introverts a platform this big to talk about the
2:18
Speaker 1: small thing that is to you. Well, it just cost
2:20
Speaker 1: us a few bananas a week, so I think that's
2:23
Speaker 1: the that's the reason. Well, bananas are hard to come
2:25
Speaker 1: by these days, you never know. But yeah, welcome to
2:27
Speaker 1: our podcasts and sometimes in this podcast we love to
2:30
Speaker 1: answer listener questions. So if you have a question, you
2:33
Speaker 1: can send it to us via questions at Daniel and
2:35
Speaker 1: Joorhead dot com or through our Twitter account. In it
2:38
Speaker 1: that's right, I'm pretty good at monitoring the Twitter page
2:41
Speaker 1: and answering listeners questions. In fact, it's the way I
2:43
Speaker 1: take a break from my day working on something hard.
2:46
Speaker 1: I'm gonna go take a break and answer some fun
2:48
Speaker 1: listener questions. Yea, and sometimes you pay questions to answer
2:51
Speaker 1: on the error. And so today on the podcast, we'll
2:54
Speaker 1: be tackling listener question number ten, particle stars and universe
3:03
Speaker 1: size black holes. And these are some of my favorite
3:06
Speaker 1: episodes because I love understanding what the listeners are thinking
3:10
Speaker 1: about and what they are wondering about. The reason that
3:13
Speaker 1: we do the person on the street interviews is it
3:16
Speaker 1: because we want to take the pulse of current knowledge.
3:18
Speaker 1: What are people understanding? What are they confused about? Because
3:20
Speaker 1: we want to educate them right there. We want to
3:22
Speaker 1: take them and unravel those points of confusion, help them
3:25
Speaker 1: have that moment of clarity of understanding when things click
3:29
Speaker 1: into place. And another way to do that is to
3:31
Speaker 1: have the listeners ask us directly something that they are
3:34
Speaker 1: wondering about. And when we get a question that I
3:36
Speaker 1: think is especially clever or hard to answer immediately, but
3:39
Speaker 1: I think other people will want to hear the answer to,
3:42
Speaker 1: then yeah, we put it on the podcast. Yeah. Do
3:44
Speaker 1: people get a reward if they stump you, Daniel? You
3:47
Speaker 1: send them about cracker Jack Prize. Yeah, I'll send you
3:49
Speaker 1: a list of people you need to send cracker Jack
3:51
Speaker 1: prizes to put that on your to do list. It's
3:54
Speaker 1: the permit scheme for the universe. They just get the
3:57
Speaker 1: joy of knowing that they've asked a really good question.
3:59
Speaker 1: And you know, we've got a lot of wonderful questions.
4:02
Speaker 1: We get questions from five year olds, we get questions
4:04
Speaker 1: from nine year olds, and all of them just reflect
4:07
Speaker 1: this desire to understand, to not live in confusion, but
4:10
Speaker 1: to have all the pieces of the universe fit into
4:12
Speaker 1: place in their minds, and that's my goal too. That's
4:15
Speaker 1: everybody's school. Yeah, and we get pretty good questions, and
4:18
Speaker 1: especially the ones we're going to cover today, I thought
4:20
Speaker 1: they were pretty cool. I was like, Wow, I don't
4:22
Speaker 1: think I know the answer to these questions, which is
4:24
Speaker 1: not saying a lot I know, but still, I've been
4:27
Speaker 1: hanging out with you for a couple of years and
4:29
Speaker 1: I feel like I don't really know the answer to
4:32
Speaker 1: these questions. Well, you know, I feel like you're a
4:33
Speaker 1: deputized physicist. I've heard you answered physics questions when I
4:36
Speaker 1: haven't been around. I thought that's a solid answer. Wow, yeah, yeah, yeah, Wikipedia,
4:41
Speaker 1: thank you no. On our live stream, Remember, I got
4:45
Speaker 1: dumped off for five minutes and came back and you
4:48
Speaker 1: had totally answered a bund of physics questions, and I thought,
4:50
Speaker 1: maybe I'm not even needed around here anymore. I've, you know,
4:53
Speaker 1: I've made myself obsolete by teaching you enough physics. I
4:55
Speaker 1: think I can probably handle answering a question. I just
4:57
Speaker 1: can't hand the follow up questions. I'm guessing it's probably
5:00
Speaker 1: when you know you need to call them real physics.
5:04
Speaker 1: But today we have some really great questions about how
5:08
Speaker 1: new stars forming, the guy about the large Hadron collider detector,
5:13
Speaker 1: and about basically everything and the Big Bang and the
5:17
Speaker 1: fate of our universe? Did they include also the meaning
5:20
Speaker 1: of life? How much of the universe can you roll
5:22
Speaker 1: up into one question? I think our third question today
5:25
Speaker 1: might take the case, well, you know, you get one shot,
5:27
Speaker 1: you might as well roll it all up into one big,
5:29
Speaker 1: fat question. All right, Well, let's get into it. Our
5:31
Speaker 1: first question comes from Meredith, and Meredith has a question
5:34
Speaker 1: about the night sky. Hi, Daniel and Jorge. My name
5:38
Speaker 1: is Meredith, and I've been wondering if new stars are
5:41
Speaker 1: always appearing in the night sky and how do we
5:44
Speaker 1: know if they're newly formed stars or if they're so
5:47
Speaker 1: far away that their light has only just reached us. Thanks, alright,
5:50
Speaker 1: awesome question, Meredith. I guess? Or question is this? I
5:54
Speaker 1: guess does the night sky change, like do we get
5:57
Speaker 1: new stars forming and disappearing all the time or is
5:59
Speaker 1: it pretty much set in the I guess lifespan of
6:03
Speaker 1: a human. Yeah, it's a wonderful question because it reflects
6:06
Speaker 1: on these differences between like human scales and human time
6:09
Speaker 1: length and cosmological timeline I'm getting the sing as you're
6:12
Speaker 1: gonna say, No, the night sky is not static. No,
6:17
Speaker 1: it's only static on the short little blip of life
6:20
Speaker 1: that we live. Right. The universe has been around for
6:22
Speaker 1: much much longer than a human life or ten human lives,
6:25
Speaker 1: or a thousand human lives or a million human lives.
6:28
Speaker 1: And that means that if you watched it on like
6:30
Speaker 1: time lapse, it would seem really active and chaotic. It's
6:33
Speaker 1: like a frothing puddle. Right. We're living sort of like
6:36
Speaker 1: in slow motion, where the universe and the galaxy seem
6:40
Speaker 1: like frozen in time, but in reality they're not. Yeah,
6:42
Speaker 1: And we have the ability to sort of look back
6:44
Speaker 1: into time, right, and also the ability to kind of
6:47
Speaker 1: project forward to sort of get a broader sense of
6:50
Speaker 1: the history of the Like, imagine that you were something
6:53
Speaker 1: that lived just a brief millisecond and you live that
6:56
Speaker 1: entire lifespan, that tiny little mill second inside an exploding
7:00
Speaker 1: grenade or something, or you know, a rock dropping into
7:04
Speaker 1: a puddle of water. It wouldn't seem very chaotic to
7:07
Speaker 1: you because on that millisecon, not that much happens. You know,
7:10
Speaker 1: things don't move very far, don't change very much. And
7:13
Speaker 1: so that's our viewpoint of the universe. We live this
7:16
Speaker 1: little brief lifespan inside a vast, very slow moving explosion.
7:21
Speaker 1: But if you watched it happened at a faster pace,
7:23
Speaker 1: you could tell that there are things bouncing off each other,
7:26
Speaker 1: there's new stars forming, there's all sorts of crazy stuff
7:29
Speaker 1: happening on the universe time scale. I was gonna say
7:31
Speaker 1: it's it's like hitting the fast forward bund, but nowadays
7:34
Speaker 1: we don't have fast forward buns. We just have like
7:36
Speaker 1: skip ten seconds funds. And that wouldn't be already Netflix
7:42
Speaker 1: that want to be very satisfying, would it? If you
7:44
Speaker 1: skip the intro of the universe, you missed most of
7:46
Speaker 1: the exciting style. Well, what if we are just living
7:48
Speaker 1: in the intro of the universe. This is just the
7:50
Speaker 1: credits and the drama hasn't even really begun. Somebody's gonna
7:52
Speaker 1: skip us. Don't skip us. No, I feel bad every
7:56
Speaker 1: time I skip the intro. That because somebody spend time
7:59
Speaker 1: making that you watch it at least once, you know,
8:01
Speaker 1: if it's more than fifteen seconds, then then I skip
8:04
Speaker 1: it every time. All right, Well, I guess the question
8:06
Speaker 1: is does the Nights Guy change and specifically, do we
8:09
Speaker 1: get new stars in the nice guy? Like, could you
8:11
Speaker 1: could I be watching this guy one of these nights
8:13
Speaker 1: when I'm out in the wild or camping and suddenly
8:16
Speaker 1: like a new star which shine that wasn't there before
8:19
Speaker 1: and nobody in human history had recorded it? Is that possible? Yeah,
8:23
Speaker 1: it's a fascinating question, and I think to understand that
8:25
Speaker 1: we have to think about, like how stars are made.
8:27
Speaker 1: Let make me think about how often that happens, and
8:30
Speaker 1: also what fraction of the Milky Way we can actually see,
8:33
Speaker 1: and those pieces together will help us answer this question,
8:36
Speaker 1: like what are the chances of that happening? Depends on
8:39
Speaker 1: all these different factors. Yeah, exactly, And so we have
8:42
Speaker 1: to remember that, like how are stars made. It's not
8:45
Speaker 1: like somebody just goes along in the simulation the universe
8:47
Speaker 1: and runs some subroutine that says make new star. Like,
8:49
Speaker 1: it happens through a process and it starts when clouds
8:53
Speaker 1: of gas collapse. Okay, so let's get into star formation then.
8:57
Speaker 1: So stars, you're saying, form when the cloud of gas
9:00
Speaker 1: out there in the universe crunched together. Yeah, and the
9:02
Speaker 1: Milky Way surprisingly is filled with these clouds. Our galaxy
9:05
Speaker 1: is a bunch of stars in its dark matter. But
9:07
Speaker 1: there's also sort of the raw materials of stars just
9:10
Speaker 1: floating around there, these vast clouds of gas. They're like
9:13
Speaker 1: seventy hydrogen and each one has like millions and millions
9:17
Speaker 1: as much mass as our sun. They're like, you know,
9:20
Speaker 1: a hundred light years wide, and there's thousands of these
9:23
Speaker 1: things just sort of floating around the Milky Way capable
9:26
Speaker 1: of making stars. It's like the raw on form basic
9:30
Speaker 1: material of stars just waiting to be you know, brought
9:34
Speaker 1: together by gravity. Yeah, it's like your star pantry, right,
9:37
Speaker 1: It's all the ingredients needed, but just not in the
9:39
Speaker 1: right arrangement. Okay. And so then eventually these clouds kind
9:43
Speaker 1: of collapse because of gravity, and then that's how stars
9:45
Speaker 1: get for Yeah, And there's a few ways that can happen.
9:48
Speaker 1: One is they just get big enough. You know, they
9:50
Speaker 1: slowly accumulate enough stuff that eventually their heat and their
9:53
Speaker 1: pressure can no longer keep them from collapsing. Right, Gravity
9:56
Speaker 1: is always working to pull stuff together, but if something
9:59
Speaker 1: is hot enough, you know that it won't collapse. Like,
10:02
Speaker 1: why isn't our atmosphere just collapsing into little stars all
10:04
Speaker 1: the time? Because it's got energy, right that overcomes that
10:08
Speaker 1: gravitational pull, like it wants to expand kind of. Yeah,
10:11
Speaker 1: it's velocity is too great for gravity from the other
10:14
Speaker 1: part of the atmosphere to pull it together. But if
10:17
Speaker 1: the gas gets heavy enough, right, there's enough mass and
10:20
Speaker 1: it's cold enough, then it can collapse. The gravity will
10:23
Speaker 1: take over and just collapse it. And so that that
10:26
Speaker 1: happens a lot in the in our Milky Way galaxy,
10:29
Speaker 1: or does it happen because I guess maybe what you're
10:32
Speaker 1: saying is that most of the stars we see when
10:35
Speaker 1: we look at it out into the night sky come
10:36
Speaker 1: from our Milky Way, So we should focus just on
10:39
Speaker 1: sort of how stars form in the Milky Way. Yeah,
10:41
Speaker 1: that's right. When you look at in the night sky,
10:43
Speaker 1: you're looking at the stars in the Milky Way, you're
10:45
Speaker 1: looking through the Milky Way out into the rest of
10:47
Speaker 1: the universe. And if you had a really good telescope,
10:50
Speaker 1: then you could see other galaxies also. They would show
10:53
Speaker 1: up looking mostly like stars, unless your telescope was super awesome,
10:56
Speaker 1: and you could tell that they had different shapes. And
10:58
Speaker 1: you know, it's only like a hundred years ago that
11:00
Speaker 1: anybody understood that those little blobs were entire other galaxies.
11:05
Speaker 1: But yeah, most of the stars that you can see
11:07
Speaker 1: are actually just stars in the Milky Way. Okay, so
11:09
Speaker 1: we have these clouds and they're making stars. But can
11:12
Speaker 1: you see these clouds in the night sky or the
11:14
Speaker 1: daytime sky or are these pretty sort of hidden from us? Well,
11:17
Speaker 1: if you ever see the band of the Milky Way,
11:19
Speaker 1: like sometimes on a really clear night when you're going camping,
11:22
Speaker 1: you see a bunch of stars and then you see
11:23
Speaker 1: sort of this milky way in the sky. Right, that's
11:27
Speaker 1: an accumulation of stars, but also gas and dust. That's
11:30
Speaker 1: where new stars would come from, and that's where new
11:32
Speaker 1: stars come from. That's the plane of the galaxy. That's
11:35
Speaker 1: the densest region of the galaxy that you're looking at.
11:38
Speaker 1: And you know, this is one of these the Orion
11:39
Speaker 1: nebula in the direction of Orion is of a light
11:43
Speaker 1: years away. It's capable of making stars. And you know,
11:47
Speaker 1: we don't quite understand the whole process of how this happens.
11:50
Speaker 1: Sometimes it's just gravitational collapse. Sometimes these clouds could collide
11:53
Speaker 1: and the points of friction provide the sort of the
11:56
Speaker 1: impetus to make the cloud collapse. Sometimes we think it
11:59
Speaker 1: might be like a super nova went off and that
12:01
Speaker 1: energy sort of triggers the cloud to collapse. It's not
12:03
Speaker 1: an inevitable thing for a star to form out of
12:06
Speaker 1: a cloud. You gotta kind of trigger it. Yeah, if
12:09
Speaker 1: the cloud gets big enough and dense enough, or if
12:11
Speaker 1: something comes along and strikes it, Yeah, then it can.
12:14
Speaker 1: Then it can happen. Okay, I guess then if you're
12:16
Speaker 1: not looking at the milk away, then is it possible
12:19
Speaker 1: that a new star will form kind of like out
12:21
Speaker 1: of the blue in between the stars. And if you
12:23
Speaker 1: look the other direction, if you're not looking in the
12:25
Speaker 1: milky way, they know, like, there aren't these clouds to
12:27
Speaker 1: make stars out between galaxies. So it's really just only
12:30
Speaker 1: in our galaxy that we could see a new star
12:32
Speaker 1: be born. There are other galaxies that make their own
12:35
Speaker 1: new stars also, but it's really hard to see a
12:37
Speaker 1: single star inside another galaxy. That's really pretty tricky. So
12:41
Speaker 1: it only really sort of be in our galaxy. And
12:44
Speaker 1: when these collapses happen, they don't just like make one star.
12:47
Speaker 1: You're talking about a cloud that's capable of making lots
12:50
Speaker 1: and lots and stars at once. And so when the
12:51
Speaker 1: collapse happens, you get a bunch of stars twins or
12:56
Speaker 1: much more than that. Yeah, exactly. I don't even know
12:59
Speaker 1: what the Latin word for that would be, but you
13:00
Speaker 1: could get thousands of stars forming basically at the same time. Wow,
13:04
Speaker 1: I see their stars are made in batches. Yeah, stars
13:08
Speaker 1: are made in batches, just like cupcakes. Right, You don't
13:10
Speaker 1: make one cupcake at a time and then they go
13:12
Speaker 1: off into the galaxy, or do they? You know, is
13:14
Speaker 1: it possible to that a star gets made somewhere and
13:16
Speaker 1: then moves in another place, or is it pretty much
13:19
Speaker 1: all condensed and concentrated in the center of the Milky Way.
13:23
Speaker 1: It could happen also two different parts of the Milky
13:24
Speaker 1: Way wherever one of these clouds are. And after the
13:27
Speaker 1: gas collapses and forms the star, it doesn't change the
13:30
Speaker 1: overall gravitational trajectory of that mass. And so whatever the
13:34
Speaker 1: center of mass of that material was doing, probably orbiting
13:37
Speaker 1: the center of the galaxy is what it will continue
13:39
Speaker 1: to be doing. So these guys will be bound together
13:41
Speaker 1: in their fates. They will be near ish each other,
13:44
Speaker 1: sort of in the vicinity, but they may end up
13:46
Speaker 1: getting spread out later, but initially they'll be moving together,
13:49
Speaker 1: all right, So then what sort of the rate or
13:52
Speaker 1: like how many new stars get made this way per
13:55
Speaker 1: per day or per year. It's hard to say like
13:57
Speaker 1: per day because it's pretty stochastic, like for this to happen,
14:01
Speaker 1: clouds have to collide or a supernob has to go
14:03
Speaker 1: off for the cloud has to reach the right critical
14:05
Speaker 1: density or something. So it's easier to talk about sort
14:08
Speaker 1: of averages. And you just think, like, how long has
14:11
Speaker 1: the Milky Way been around, Well, about thirteen billion years,
14:14
Speaker 1: and how many stars are there? Right, and there's a
14:18
Speaker 1: hundred billion stars, right, and so that means that roughly
14:23
Speaker 1: about every forty seven days in the history of the
14:26
Speaker 1: Milky Way, a star has been made. Now, it's not
14:29
Speaker 1: like every forty seven days a new one turns on.
14:31
Speaker 1: You know, you get a thousand made, and then you
14:33
Speaker 1: might go years and years before another one is made.
14:35
Speaker 1: Then you get another thousand. But on average it's every
14:38
Speaker 1: forty seven days. It's like Los Angeles star is born
14:41
Speaker 1: every forty seven days, and a sucker is born every day.
14:46
Speaker 1: There's a lot more suckers than stars. Yeah, exactly. Okay,
14:50
Speaker 1: So an average, the Milky Way makes like one star
14:53
Speaker 1: every month and a half. Yeah, one star every month
14:55
Speaker 1: and a half. That's its rate of production. And you know,
14:57
Speaker 1: the Milky Way is a big place, so that's not
15:00
Speaker 1: a whole lot of new stars. You know, one star here,
15:02
Speaker 1: another star could be on the other side of the
15:04
Speaker 1: Milky Way. It's like a hundred thousand light years away.
15:07
Speaker 1: So it's not that many because we can't see all
15:09
Speaker 1: of them, right, But I guess of thinking about the
15:11
Speaker 1: ones that we could see, what would be the rate,
15:13
Speaker 1: do you think? Yeah, I think people would be surprised
15:15
Speaker 1: to understand that when you look up at the night sky,
15:17
Speaker 1: you're seeing a very small fraction of the Milky Way
15:19
Speaker 1: because most of the Milky Way, the stars are too
15:22
Speaker 1: far away for you to see them. Like, your naked
15:24
Speaker 1: eye is not good enough at capturing those photons from
15:27
Speaker 1: those stars. The stars from the other side of the
15:29
Speaker 1: Milky Way, they're shooting their light at us, and it's
15:32
Speaker 1: getting here. But you know, you might get like one
15:33
Speaker 1: photon per minute. And so if you're looking up at
15:36
Speaker 1: the night sky with a naked eye, you're only actually
15:38
Speaker 1: seeing a few thousand stars of the Milky Way. Of
15:41
Speaker 1: the hundred billion stars in the Milky Way, you're not
15:45
Speaker 1: seeing all the stars you could be seeing of the
15:48
Speaker 1: Milky Way. That's right. If you had like two hubbles
15:50
Speaker 1: for eyeballs, you would see a lot more stars. Right.
15:52
Speaker 1: It'd be kind of awkward to like getting your car
15:54
Speaker 1: or walk around, but you'd have a great view at night,
15:56
Speaker 1: like if my eyes were bigger or I had like
15:58
Speaker 1: super night vision. Know, I mean, like literally, if you
16:01
Speaker 1: had two hubbles attached to your eyeballs, you're being literal.
16:06
Speaker 1: Was being literal, I was fantasizing from like go up
16:08
Speaker 1: into space, grabbing one of these peas cups and sticking
16:11
Speaker 1: in your eyes. Imagine what you could see um. And
16:14
Speaker 1: so essentially that defines like a sphere, you know, nearby
16:18
Speaker 1: stuff that you could see. So for us to see
16:20
Speaker 1: a star be born, you would have to be born
16:22
Speaker 1: fairly close to the earth. And again it depends like
16:25
Speaker 1: how bright it is. If it's brighter, it could be
16:27
Speaker 1: born further away. If it's dimmer, and have to be
16:29
Speaker 1: born closer. And so we could just do a simple
16:32
Speaker 1: division again and say, well, there's a few thousand visible
16:35
Speaker 1: stars the Milky Ways, billions and billions of years old.
16:38
Speaker 1: Do the math, and you get that a new visible
16:40
Speaker 1: star appears about every million years. Oh, I see. If
16:44
Speaker 1: I were to look at the night sky, I would
16:47
Speaker 1: have to on average wait a million and a half
16:50
Speaker 1: years to see a new star. Yeah, exactly to see
16:53
Speaker 1: a new star be born. So not likely, not likely,
16:57
Speaker 1: although you could get lucky. You could watch for ten
17:00
Speaker 1: minutes and see a hundred stars appear. Right. That could happen,
17:03
Speaker 1: because you could get a cluster of stars born near
17:06
Speaker 1: the earth. But yeah, I wouldn't bet on it. You
17:09
Speaker 1: could win the lottery, it's possible, Yeah, you could. And
17:15
Speaker 1: she also asked about how do we know if the
17:17
Speaker 1: stars are newly formed or if the light is just
17:20
Speaker 1: reaching us? Right, which is another great question. Yeah, like
17:22
Speaker 1: if I see something from if I am looking at
17:25
Speaker 1: the next guy and I see something turn on like blink,
17:28
Speaker 1: how do we know it's a star that formed or
17:30
Speaker 1: maybe a star that what the form a long time
17:33
Speaker 1: ago and now I'm seeing it. What's the difference in
17:35
Speaker 1: her question? Yeah, I think she's asking did the star
17:37
Speaker 1: just form if it turns on, or did it form
17:39
Speaker 1: a long time ago and we're just now seeing the light.
17:42
Speaker 1: And the answer is always the second. It's always that
17:44
Speaker 1: we're just now seeing the light. And it formed a
17:46
Speaker 1: while ago. If it formed really close to the Earth,
17:49
Speaker 1: we'd be in trouble, right, No need another star really
17:51
Speaker 1: close to the earth. So that means it has to
17:53
Speaker 1: have formed somewhere far away, which means it takes light
17:56
Speaker 1: a while to get here. And and she also asks, like,
17:59
Speaker 1: you know, how do we know? We can measure the
18:01
Speaker 1: distance to these stars using various methods. We had a
18:04
Speaker 1: whole podcast about it. We can like look at it
18:06
Speaker 1: from telescopes from different parts of the Earth and see
18:08
Speaker 1: it shift, sort of the way you can tell how
18:10
Speaker 1: far away something is by changing your eyeballs by opening
18:13
Speaker 1: one eyeball or just the other one. With houbble telescopes,
18:18
Speaker 1: that would be awesome at telling how far away basketball is.
18:22
Speaker 1: So we have ways to tell how farstening is away.
18:24
Speaker 1: And then we can tell this light from this star
18:26
Speaker 1: that has just arrived since this five million years away,
18:29
Speaker 1: that means the star formed five million years ago. Okay,
18:32
Speaker 1: So I guess that the lesson is if you are
18:34
Speaker 1: seeing a newly formed star in real time, then you're
18:37
Speaker 1: kind of in big trouble. That's right, because that means
18:40
Speaker 1: you're we you shoet have war more sun screened. Yeah,
18:44
Speaker 1: I'd say run, but there's nowhere to run dig maybe.
18:49
Speaker 1: All right, well that I think that answer is may
18:51
Speaker 1: this question, which is that new stars are appearing in
18:54
Speaker 1: the night sky, the answer is yes, but they probably
18:58
Speaker 1: don't happen that often, maybe every one and a half
19:00
Speaker 1: million years. So we're sort of blessed and stuck with
19:03
Speaker 1: the nights guy that we have right now. That's right,
19:05
Speaker 1: but hey, you never know. I wish upon a star
19:07
Speaker 1: and maybe you'll see one. All right, let's get into
19:09
Speaker 1: our other questions. We have more questions here about the
19:12
Speaker 1: large Hadron collider and what Daniel actually does as a job,
19:16
Speaker 1: and about the Big Bang and black holes. But first
19:20
Speaker 1: let's take a quick break. All right. We're answering listener
19:36
Speaker 1: questions and our next question comes from Hunter from Buffalo, Wyoming,
19:40
Speaker 1: and he answer a question about what exactly does Daniel
19:44
Speaker 1: do at this job other than napping. Let's get into it, alright,
19:48
Speaker 1: and drinking coffee somehow at the same time. I don't
19:51
Speaker 1: know how you do it. You have the coffee, then
19:53
Speaker 1: you have the nap. That's the key. Anyway, here's Hunter's question.
19:57
Speaker 1: Hey you guys, my name is Hunter from Buffalo, A Wyoming,
20:01
Speaker 1: And my question for you is, how does the detector
20:05
Speaker 1: at CERN actually work? How does this massive device detect
20:09
Speaker 1: these tiny, tiny particle interactions? And when they do shoot
20:14
Speaker 1: particles together, how do they make them hit each other?
20:17
Speaker 1: I mean, these particles are so small and they're going
20:20
Speaker 1: in this massive chamber. You figure that there's a chance
20:25
Speaker 1: that they miss each other. So how do they do it? Thanks?
20:28
Speaker 1: All right, thank you, Hunter Daniel. I feel like Hunter
20:31
Speaker 1: is kind of skeptical about your your professional year. He
20:34
Speaker 1: doesn't seem like it should work. Are you sure that skepticism?
20:37
Speaker 1: Maybe it's all Maybe it's wonder right. You see, he's amazed.
20:42
Speaker 1: He's amazed that you have a job. I'm amazed that
20:45
Speaker 1: I have a job doing this. Sometimes. I mean I
20:47
Speaker 1: get to like tear apart matter and figure out what
20:49
Speaker 1: it's made out of. As a job, I feel pretty
20:52
Speaker 1: lucky and special sometimes awesome. And so his question is
20:55
Speaker 1: how does the large hadron collider detector actually work? I
20:59
Speaker 1: guess he's he's sort of wondering about the mechanics because
21:01
Speaker 1: it seems like, we know, you guys smashed particles together.
21:04
Speaker 1: But I guess this question is that it seems something
21:08
Speaker 1: impossible to do, Like, how do you take a pin
21:10
Speaker 1: and have it hit the head of another pin and
21:12
Speaker 1: actually see what happened. Yeah, it's a great question, and
21:16
Speaker 1: it's fascinating because he asked questions about the only two
21:18
Speaker 1: parts that we can do, which is like, try to
21:21
Speaker 1: smash stuff together and then look at the stuff that
21:23
Speaker 1: comes out. We can't actually see the collision itself, right,
21:27
Speaker 1: this moment of collision when something magical happens will not magical. Obviously,
21:31
Speaker 1: something scientific happens and the new particle is made. That
21:34
Speaker 1: moment is invisible to us. But we can try to
21:36
Speaker 1: control the initial situation, what we're shooting in at what energy,
21:41
Speaker 1: and then we can try to observe what comes out
21:43
Speaker 1: the eventual stuff. So the first part is like how
21:46
Speaker 1: do you shoot these things together and actually make them hit?
21:49
Speaker 1: And you totally right, Hunter that if you shot one
21:51
Speaker 1: proton at another proton, you would miss, I mean did again,
21:55
Speaker 1: you would miss, and you'd miss like a hundred billion
21:57
Speaker 1: times before maybe you would hit, So that it's not
22:00
Speaker 1: what we do. Instead, what we do is we fill
22:03
Speaker 1: our guns with a hundred billion protons and we shoot
22:06
Speaker 1: it at a hundred billion protons, and we shoot those
22:08
Speaker 1: little like clouds of protons at each other. I see.
22:12
Speaker 1: It's kind of like dating. Do you get to do
22:15
Speaker 1: a lot of swives before you find the right person? Yeah, exactly,
22:18
Speaker 1: you gotta throw a lot of darts at the wall,
22:20
Speaker 1: and so here, essentially we're throwing a cloud of darts
22:22
Speaker 1: against another cloud of darts and hoping that the tips meet.
22:26
Speaker 1: And you don't just throw a bunch of darts, you
22:28
Speaker 1: throw like a bazillion darts a bazillion times a second. Yeah,
22:32
Speaker 1: every twenty five nano seconds, one of these bunches bunches,
22:36
Speaker 1: the technical term we use for this little cloud of
22:38
Speaker 1: protons were very fancy. One bunch which contains you know,
22:41
Speaker 1: a hundred billion protons passes through another bunch, and that's
22:45
Speaker 1: every twenty five seconds. We do it twenty four hours
22:47
Speaker 1: a day, three sixty five days a year. And do
22:50
Speaker 1: you call these collections of protons bunches? Then I know
22:54
Speaker 1: you're trend is. If you collect particles, that's another particle.
22:58
Speaker 1: I'm feeling some schmid here now about our naming scheme.
23:02
Speaker 1: You know, we call those bunches and we collide them,
23:05
Speaker 1: and you know, it's really it's an amazing engineering achievement
23:08
Speaker 1: to build this thing, to accelerate the particles to this energy,
23:11
Speaker 1: to focus those beams to the smallest possible dot, to
23:14
Speaker 1: maximize the number of collisions we get. And when you
23:17
Speaker 1: pass a hundred billion protons through another hundred billion protons,
23:21
Speaker 1: both going and nearly the speed of light, you don't
23:23
Speaker 1: get a hundred billion collisions. You get like sometimes zero,
23:26
Speaker 1: sometimes five, sometimes ten, sometimes twenty five collisions. So the
23:30
Speaker 1: probability is pretty low. It's like five in ten to
23:33
Speaker 1: the ten. It's very small. Yeah, and the probability gets
23:36
Speaker 1: better the tighter you can make your beam or the
23:38
Speaker 1: denser you can make that little cloud, the smaller the
23:41
Speaker 1: area over which you're spreading those protons. But it's not
23:44
Speaker 1: very high. And even when we get collisions, mostly those
23:47
Speaker 1: collisions are pretty boring. It's proton bounces off of proton.
23:50
Speaker 1: Nothing happens, protons going protons like Billard balls. They just deflect. Yeah,
23:55
Speaker 1: they just deflect. That's like nine nine percent at the time.
23:58
Speaker 1: What happens. Usually it's not very exciting. I guess one
24:01
Speaker 1: proton repels another proton, so they just kind of like
24:04
Speaker 1: push each other away. Yeah, they're both possitively charged and
24:06
Speaker 1: they will interact. But that's the most likely thing to happen.
24:09
Speaker 1: If you're throwing darts at a wall, you know, most
24:11
Speaker 1: of the spots on that dartboard are proton bouncedself proton.
24:15
Speaker 1: Sometimes you hit the spot where like it makes a
24:17
Speaker 1: Higgs boson, or it makes some new weird particle. And
24:20
Speaker 1: that's why we do it so often, because we're sifting
24:23
Speaker 1: through so many collisions looking for the rare one that
24:27
Speaker 1: will help us see something new. We think the weird
24:29
Speaker 1: stuff is rare, so we have to look at a
24:31
Speaker 1: lot of collisions to find them. Seems like sifting through
24:34
Speaker 1: sand for a special grain of sand. Yeah. I think
24:36
Speaker 1: that's probably a lot like tinder, right, just like you
24:38
Speaker 1: were saying, it's a lot like data. Um, you're looking
24:41
Speaker 1: for that one special somebody, and you've gotta look through
24:43
Speaker 1: a lot of people sometimes to find the one that fits.
24:45
Speaker 1: And so part of a hunter's question was, first of all,
24:47
Speaker 1: how do you smash it together? I think you can
24:49
Speaker 1: answer that, But now how do you tell what actually happened?
24:52
Speaker 1: You know, because I imagine these are, you know, small
24:55
Speaker 1: things that smashed together. How do you actually tell what
24:58
Speaker 1: happened when they smashed together. Yeah, you can't just like
25:00
Speaker 1: take a video. We'd love to do that, but first
25:03
Speaker 1: of all, these things happened too fast. So for example,
25:06
Speaker 1: a Higgs boson or a top cork, if you make it,
25:08
Speaker 1: it lasts for ten to the minus twenty three seconds
25:12
Speaker 1: before it turns into other particles, So you just can't
25:14
Speaker 1: see it. Like, we don't have cameras that are that fast,
25:17
Speaker 1: and on top of being super duper short lived, they're
25:21
Speaker 1: super duper tiny, and we don't have cameras that can
25:24
Speaker 1: see things that's small, and so they're smaller than the
25:27
Speaker 1: wavelength of light we could use, so we don't see
25:30
Speaker 1: at all these collisions. They're totally invisible to us. It's
25:32
Speaker 1: like they happen behind a dark curtain. Instead, what we
25:36
Speaker 1: see is that what they turned into is you know what,
25:38
Speaker 1: trot's out onto the stage in front of the curtain. Hre.
25:41
Speaker 1: It's more like showing up at an intersection after a
25:44
Speaker 1: car crash and trying to figure out what happened because
25:46
Speaker 1: we see the remnants, you see, like the bits and pieces. Yeah,
25:49
Speaker 1: the Higgs or the top or whatever happened will turn
25:52
Speaker 1: into other particles that do last long enough that we
25:54
Speaker 1: can observe, and so we look at those we try
25:57
Speaker 1: to figure out from what's left over, from what was produced,
26:00
Speaker 1: what actually happened in that exciting moment of collision. And
26:02
Speaker 1: that's kind of what you see when you look up
26:04
Speaker 1: pictures of the large Hattern collider. They mostly show you detectors,
26:08
Speaker 1: like the giant machines used to figure out what came
26:12
Speaker 1: out of these collisions, like the huge cylinder and the
26:15
Speaker 1: sort of warehouse size machines and the little tiny people
26:18
Speaker 1: standing in front of it. That's that's kind of what
26:21
Speaker 1: you see, right. It's it's the detectors, not the actual
26:23
Speaker 1: like gun that shoots the proton. That's right. And in fact,
26:26
Speaker 1: they're totally different communities of people that work on that.
26:29
Speaker 1: Like I work at SIR and I work on the
26:31
Speaker 1: l C. I don't work on the accelerator at all.
26:33
Speaker 1: I have no expertise in building an accelerator. But I
26:36
Speaker 1: work on a group of people that built the detector
26:38
Speaker 1: that surrounds this collision point to take some kind of
26:41
Speaker 1: digital picture of what flew out of it. And that's
26:43
Speaker 1: what you're describing, these huge detectors. And so this, for example,
26:48
Speaker 1: I'm in the Atlas collaboration, and there are four places
26:50
Speaker 1: around the ring where people have built these detectors to
26:53
Speaker 1: surround it. And so the Atlas Collaboration built the Atlas detector,
26:57
Speaker 1: and a lot of the other detectors follow a similar scheme. Essentially,
27:00
Speaker 1: what you're trying to do is take pictures of the
27:03
Speaker 1: particles that fly out, but again you can't directly image them.
27:06
Speaker 1: You have to measure somehow their properties. You have to
27:08
Speaker 1: measure what they're doing. It. It's not just about capturing them.
27:11
Speaker 1: It's like, oh, it was going this way with the speed,
27:13
Speaker 1: with this momentum. That's exactly it. And so what we
27:15
Speaker 1: do is we pass all the particles through a magnetic
27:18
Speaker 1: field because by seeing how much they curve in that field,
27:22
Speaker 1: we can measure their momentum and we can also tell
27:24
Speaker 1: if they had an electric charge or not. And then
27:26
Speaker 1: we have another layer of detectors that tries to measure
27:29
Speaker 1: their energy. And so by putting these pieces of information together,
27:32
Speaker 1: we can sort of tell what the particle was because
27:35
Speaker 1: everything has a distinct signature, like an electron is a charge.
27:38
Speaker 1: Particle will bend in that magnetic field and then it
27:41
Speaker 1: will splash a bunch of its energy in that outer layer,
27:44
Speaker 1: whereas a photon won't bend in that magnetic field would
27:47
Speaker 1: be totally invisible, but then it will leave a splash
27:49
Speaker 1: in the outer field. So we can sort of tell
27:51
Speaker 1: what was what by piecing this together, but we never
27:54
Speaker 1: we never get like a picture. It's like, oh, look,
27:55
Speaker 1: this is the electron that was made. It's all like
27:58
Speaker 1: we see tracks in the snow and we deduced from that,
28:01
Speaker 1: you know what ran away. It's like your kid leaving
28:04
Speaker 1: a mess. You're like, there was definitely a kid here.
28:07
Speaker 1: There's a bucket of paint's built and I see little footprints,
28:10
Speaker 1: so I'm pretty sure I know who's here. Delighted here,
28:14
Speaker 1: and it's done instead of layers, right, Like, I think
28:16
Speaker 1: that's cool that first you have the magnetic field and
28:18
Speaker 1: that's how you measure momentum and charge, and then you
28:20
Speaker 1: have a whole another layer that measures the energy, and
28:23
Speaker 1: then another layer that measures other things. Yeah, because some
28:26
Speaker 1: things escape, right, there's the layer that measures energy. It's
28:29
Speaker 1: job is to slow the particle down to grab all
28:32
Speaker 1: of its energy in order to measure it. But some
28:34
Speaker 1: particles get right through there, like a muan will fly
28:37
Speaker 1: right through. It hardly interacts with that detector, and so
28:39
Speaker 1: we have a whole other layer of detectors on the
28:42
Speaker 1: outside to try to bend muans and measure their energy.
28:46
Speaker 1: So muans get bent twice, one in the inner magnetic
28:49
Speaker 1: field and then one in the outer magnetic field, and
28:52
Speaker 1: then some things escape completely, like neutrinos. If they're produced
28:55
Speaker 1: in these collisions, they're just totally invisible to us. We
28:58
Speaker 1: can't see them at all. Know, would fly through like
29:01
Speaker 1: a light year of lead before interacted, So there's no
29:04
Speaker 1: chance it would interact with our detector unless you put
29:06
Speaker 1: a light year of lead. Yeah, I'm gonna write that
29:08
Speaker 1: grand proposal, kind of get a cubic light year of lead, please,
29:12
Speaker 1: that's right. Then you put it in your eyeballs and
29:15
Speaker 1: you would be able to see Natrina even if the
29:17
Speaker 1: n SF said, yes, tod that, Where would you even
29:19
Speaker 1: source a cubic light year of lead? Like seriously? All right, well, um,
29:25
Speaker 1: I think that's that kind of answers. The question is
29:27
Speaker 1: how does the L A C detector actually work? It works,
29:32
Speaker 1: and it works by amazing feats of engineering where you
29:36
Speaker 1: take bazillions of protons and smashing bazillions of times a second,
29:40
Speaker 1: and then using incredible and warehouse size machines. You kind
29:45
Speaker 1: of track what happens and what comes out of these cours. Yeah,
29:48
Speaker 1: and for every collision, we read out a hundred million
29:51
Speaker 1: pieces of information and we do that every million, million,
29:56
Speaker 1: hundred million. That's for one channel, and each channel can
29:58
Speaker 1: have you know, bites and bite of data. And so
30:01
Speaker 1: we have a lot of data coming out of this
30:03
Speaker 1: thing because it's every twenty five nanoseconds, and so we're
30:06
Speaker 1: just producing petabytes and petabytes of data and so actually
30:09
Speaker 1: most of it we throw away. Most of it we
30:12
Speaker 1: filter it away really quickly because usually it's boring right
30:15
Speaker 1: to protons collide, to protons come out, that goes in
30:17
Speaker 1: the trash. So a lot of the stuff that we
30:19
Speaker 1: do is making rapid keep it or kill it decisions.
30:22
Speaker 1: And that's kind of what you do, right that that's
30:24
Speaker 1: kind of your part in this whole giant scientific endeavor
30:27
Speaker 1: as you used to work on an algorithms that try
30:29
Speaker 1: to sift through this data and throughout the ones that
30:31
Speaker 1: we don't need. That's right. Part of being in a
30:33
Speaker 1: collaboration of like five thousand people, becoming a specialist is
30:36
Speaker 1: saying I'm gonna do this bit and you do that bit.
30:38
Speaker 1: And the bit that I personally work on, that my
30:40
Speaker 1: group works on is this trigger system that makes the
30:43
Speaker 1: keep it or kill it decisions every twenty five nanoseconds.
30:45
Speaker 1: And it's not just me it there's a collaboration of
30:47
Speaker 1: hundreds of people who work on on that one system
30:50
Speaker 1: in this huge detector filtering the car crash at the universe.
30:55
Speaker 1: It's sort of terrifying sometimes because if you make the
30:57
Speaker 1: wrong decisions, you're just throwing it away. Like once I did,
31:00
Speaker 1: it's gone. It's gone forever. And so we worry that
31:04
Speaker 1: sometimes in the in the garbage that we're throwing out
31:06
Speaker 1: could be hidden nuggets, things that could reveal fascinating insights
31:10
Speaker 1: into the universe. But you know, hey, we're throwing it
31:12
Speaker 1: in the trash. Pressure. All right, well, thank you Hunter
31:16
Speaker 1: from Buffalo for asking that question, and so we'll get
31:19
Speaker 1: into our last question of today, which is about the
31:21
Speaker 1: Big Bang and black holes. But first let's take a
31:25
Speaker 1: quick break, al right, Dianiel. Our last question of the
31:39
Speaker 1: day here, it comes from Charles who has a question
31:42
Speaker 1: about the Big Bang. And it's a big question. It's
31:46
Speaker 1: a big it's a hole of a question. It's a
31:48
Speaker 1: whole big question. So here's what Charles wanted to Hey, guys,
31:52
Speaker 1: so we know that black holes appear when a huge
31:55
Speaker 1: amount of mass is compacted into a tiny area of space.
32:00
Speaker 1: So my question is, if during the Big Bang all
32:03
Speaker 1: the matter in the universe was gathered into a really
32:07
Speaker 1: small area of space, why didn't the Big Bang become
32:10
Speaker 1: a giant black hole? Boom wow? When an awesome question.
32:15
Speaker 1: It takes me a second just to kind of run
32:17
Speaker 1: my head around it. Then make your head go boom
32:20
Speaker 1: or I guess what's the sound of a black hole
32:22
Speaker 1: being made? It's not boom, is it? It's like, uh, well,
32:26
Speaker 1: I guess I've never kind of heard the words big
32:29
Speaker 1: bang and black hole in the same sentence, have you?
32:33
Speaker 1: Is it? It's not normal. Yeah, it's a fascinating topic,
32:36
Speaker 1: and you know, we can get into it. But there
32:38
Speaker 1: are black holes that were made in the first moments
32:40
Speaker 1: of the Big Bang, and they have this awesome, awesome
32:43
Speaker 1: title primordial black holes, one of my favorite names in physics.
32:47
Speaker 1: They have little tales like lizards. But I guess the
32:50
Speaker 1: question from Charles is, you know, we know that black
32:52
Speaker 1: holes form when you get enough mass and stuff kind
32:56
Speaker 1: of compacted and crushed together into the right sort of
33:00
Speaker 1: as and the small enough volume, and so the Big Bang.
33:04
Speaker 1: At some point in the Big Bang, there was a
33:06
Speaker 1: lot of stuff in a very small amount of space.
33:09
Speaker 1: So why didn't the Big Bang not bang? Why did
33:13
Speaker 1: it bang after all? Why didn't bang? Why why did
33:15
Speaker 1: it bang so bigly? Why why didn't it just collapse
33:18
Speaker 1: into a black hole and stay not big bang? Yeah? Well,
33:21
Speaker 1: I'm glad it didn't because if it had, you know,
33:23
Speaker 1: we wouldn't be here to ask this question, and we
33:25
Speaker 1: wouldn't have this amazing, crazy puzzle of a universe to
33:29
Speaker 1: try to unravel. And I think the first sort of
33:31
Speaker 1: idea to unravel here is to work out, like, what
33:33
Speaker 1: are the necessary ingredients for a black hole? How do
33:36
Speaker 1: you make a black hole? What has to happen for
33:38
Speaker 1: a black hole to form? Because then because then that
33:41
Speaker 1: will tell us kind of how it's different from the
33:42
Speaker 1: conditions of the Big Bang, exactly exactly right. And I
33:46
Speaker 1: think a lot of people think, oh, all you need
33:48
Speaker 1: for a black hole is just a lot of stuff.
33:50
Speaker 1: If a lot of stuff and it's dense enough, bloom,
33:52
Speaker 1: you get a black hole. And you painted black, right,
33:55
Speaker 1: you painted black? And then you sing that awesome song
33:57
Speaker 1: from the Stones. Right, people think you just need to
34:00
Speaker 1: create enough density and will collapse into a black hole. Yeah,
34:03
Speaker 1: and that's close to true. Right. It's true that you
34:05
Speaker 1: need a lot of energy density in one spot. Right,
34:08
Speaker 1: you need one location with a huge amount of stuff
34:11
Speaker 1: in it, and that can curve space. That's that's how
34:14
Speaker 1: it happens. But the other thing you need is you
34:17
Speaker 1: need that to happen in flat space. Right. We talked
34:20
Speaker 1: about how space is curved, right, how space is expanding.
34:24
Speaker 1: Space is not just like the backdrop for It's not
34:26
Speaker 1: just like emptiness and you're putting stuff into it and
34:29
Speaker 1: filling it up. Space responds to matter, Space high responds
34:33
Speaker 1: to other things as well, forces and fields, and so
34:36
Speaker 1: it's dynamical. It changes, it can grow, it can squish,
34:39
Speaker 1: you can do all sorts of stuff. The canonical picture
34:42
Speaker 1: of a black hole we have is in non expanding space,
34:46
Speaker 1: is in space that's not growing. And so it's true
34:49
Speaker 1: that if you have non expanding space, just like you
34:51
Speaker 1: know a flat universe, and you put a bunch of
34:53
Speaker 1: matter into it, then yes, it will form a black hole.
34:56
Speaker 1: It will create curved space in that region that I
35:00
Speaker 1: cannot escape. I see you need like um, you know,
35:02
Speaker 1: static space almost you need like space that's just sitting
35:06
Speaker 1: there chill. Yes, yeah, and that's the solution that was discovered. Right.
35:10
Speaker 1: Remember black holes were discovered theoretically before they were actually
35:13
Speaker 1: seeing experimentally. It was an idea that came out of
35:16
Speaker 1: looking at the equations and people were studying Einstein's at
35:19
Speaker 1: the time fairly new equations for general relativity and thinking,
35:23
Speaker 1: all right, what are the consequences for the universe. Let's
35:26
Speaker 1: look at what would happen in this scenario that scenario,
35:28
Speaker 1: And one scenario they found is in static space and
35:31
Speaker 1: non expanding space. If you put enough stuff in there,
35:35
Speaker 1: then you get this weird feature of black hole. And
35:37
Speaker 1: then you know, they went out and they actually found
35:39
Speaker 1: it in the universe. But the theoretical concept of a
35:41
Speaker 1: black hole starts from static space, as you say, or
35:45
Speaker 1: we know that spaces expanding now, but it's not expanding
35:48
Speaker 1: in a crazy way, like you can still make a
35:50
Speaker 1: black hole as long as the space itself is not
35:52
Speaker 1: expanding too much. Yes, And so that's exactly the reason
35:55
Speaker 1: why the Big Bang didn't just make a black hole
35:58
Speaker 1: is that it was crazy expanding back then it's still expanding.
36:01
Speaker 1: Now we have dark energy when they the universe is expanding,
36:04
Speaker 1: and that expansion is even accelerating. But back in the
36:08
Speaker 1: early days, like during inflation and the Big Bang, it
36:11
Speaker 1: was crazy expansion. Space was stretching and creating new space
36:16
Speaker 1: at an incredible rate. Yeah, and we don't understand you know,
36:19
Speaker 1: what caused that and how it worked. We call it
36:21
Speaker 1: inflation just to sort of describe the expansion that we
36:24
Speaker 1: think was happening. But you need a lot more density
36:27
Speaker 1: in the early days of the universe to make black holes.
36:31
Speaker 1: Given that expansion, it's like you have another force to
36:34
Speaker 1: contend with. We talked about on the Cosmological Constant podcast
36:37
Speaker 1: recently how the Cosmological constant, this force is providing this
36:41
Speaker 1: like repulsive gravity. It's like pushing things away. It's it's
36:44
Speaker 1: expanding space. It's working against gravity. So you need enough
36:48
Speaker 1: stuff to overcome that as well. But it is possible,
36:51
Speaker 1: like if bad enough stuff, like I'm writing The Big
36:53
Speaker 1: Bang and I put enough stuff together, I could have
36:55
Speaker 1: formed a black hole. It's a fascinating question. And people
36:58
Speaker 1: think about this and they think about, like, if you
37:00
Speaker 1: had enough stuff, could you have collapsed the universe. You
37:03
Speaker 1: have canceled out the black big band. Yeah, and we
37:06
Speaker 1: can dig into that into in a moment. But you
37:08
Speaker 1: need one more things that you needed to be not
37:10
Speaker 1: totally smooth. Like, if you have enough stuff and it's
37:13
Speaker 1: totally smooth, then where are these black holes going to form? Right?
37:17
Speaker 1: How do you pick where the black holes are? The
37:20
Speaker 1: other thing you need for a black hole is you
37:21
Speaker 1: need a bunch of stuff in one spot. But if
37:24
Speaker 1: everywhere in the universe has the same amount of stuff
37:27
Speaker 1: in it, then all the gravity just cancels out. Really, yeah,
37:31
Speaker 1: you can cancel a black hole. Well, it won't form
37:33
Speaker 1: a black hole, right, You won't form a black hole
37:36
Speaker 1: if the universe is filled perfectly smoothly with stuff. And
37:39
Speaker 1: we think now that the beginning of the universe, the
37:42
Speaker 1: universe was infinite. It's not like the Big Bang was
37:46
Speaker 1: one little dense pocket of stuff. The whole universe tucked
37:49
Speaker 1: into an atom. We think it was an incredible density,
37:52
Speaker 1: but it was still infinite. The whole universe was filled
37:55
Speaker 1: with an infinite amount of stuff, just very very dense.
37:58
Speaker 1: So in that configuration, if it totally smooth and very
38:01
Speaker 1: very dense, then where did these black holes form? It's
38:05
Speaker 1: like you can't make a chocolate chip out of a
38:07
Speaker 1: chocolate bark. Kind of I'm grasping for analogies here, but
38:12
Speaker 1: is that kind of like it's it's hard to see
38:14
Speaker 1: the black hole, or it's hard to like all that
38:17
Speaker 1: matter that dance everywhere doesn't doesn't like forming into black holes. Yeah.
38:22
Speaker 1: I think there's two different arguments you could use your
38:24
Speaker 1: mind to understand it. One is, take one particle, right,
38:28
Speaker 1: think about one particle in the early moments there. If
38:31
Speaker 1: if the universe is filled with stuff and there's the
38:33
Speaker 1: same amount of stuff on its left and it's right,
38:36
Speaker 1: it's gonna be pulled in both directions equally, and so
38:38
Speaker 1: those forces will cancel. And the same if you go
38:41
Speaker 1: up or down or forward or backwards, and so all
38:43
Speaker 1: those forces cancel. And the same argument applies for every
38:46
Speaker 1: particle in the universe. Another way to think about it
38:49
Speaker 1: is like symmetry, Like if black hole is gonna form,
38:52
Speaker 1: it's got to form somewhere. And if every place in
38:55
Speaker 1: the universe is the same, then how did those get chosen?
38:58
Speaker 1: So there's no way to choose where they happen, So
39:01
Speaker 1: they just can't, I guess, to form a black hole.
39:04
Speaker 1: You need sort of need some space around you, not
39:06
Speaker 1: just a lot of mass and chill space, but you
39:09
Speaker 1: also need to not have a lot of stuff around
39:11
Speaker 1: you otherwise, like the stuff that you have would have
39:13
Speaker 1: condense and compressed. Yes, it's not just that you need density.
39:16
Speaker 1: You need more density than the areas around you. Right,
39:19
Speaker 1: If everything is dense, but it's equally dense, nothing gets
39:22
Speaker 1: the form of a black hole. If everything is dense
39:24
Speaker 1: and you have one hyper dense spot, then that could
39:27
Speaker 1: collapse into a black hole. I can have a black hole.
39:29
Speaker 1: No one can have a black hole, that's right. And
39:32
Speaker 1: you know, we did have these little areas of inhomogeneity
39:36
Speaker 1: that came from quantum fluctuations and were blown up by inflation.
39:40
Speaker 1: And so people do wonder, like, even after inflation, why
39:44
Speaker 1: wasn't there so much stuff that the universe immediately collapsed
39:47
Speaker 1: wherever those little pockets, those little seeds of things that
39:51
Speaker 1: that allowed structure in the universe to form, those little
39:54
Speaker 1: areas that were slightly denser that came from the quantum
39:56
Speaker 1: fluctuations that were expanded from inflation, Why didn't those just
40:00
Speaker 1: immediately trigger black holes? All right? Why did they happen
40:03
Speaker 1: to form enough gravity to pull together to make galaxies
40:06
Speaker 1: and stars and planets and not just collapse into black holes.
40:09
Speaker 1: And that we don't know the answer to. It's just
40:11
Speaker 1: like we had enough stuff to make structure, but not
40:15
Speaker 1: so much that we just collapsed immediately into black holes,
40:18
Speaker 1: and we're sort of lucky. I guess that only works
40:20
Speaker 1: if the universe is infinite. If the universe was finite,
40:23
Speaker 1: the big band could have become a black hole. If
40:24
Speaker 1: the universe was finite, then it's still very, very large.
40:27
Speaker 1: It's at least larger than you know, the age of
40:30
Speaker 1: the universe, times and speed of light and you factor
40:32
Speaker 1: and all the inflation. So that's a huge amount of stuff.
40:35
Speaker 1: That's too much stuff to instantly collapse into a black
40:38
Speaker 1: hole just because the speed of light would take too
40:40
Speaker 1: long to cross it near the edges. I suppose if
40:42
Speaker 1: space is flat and matter ends, then you could get
40:46
Speaker 1: collapsing black holes. But we're not living near the edge.
40:49
Speaker 1: If there is one, because we can see isotropic universe
40:52
Speaker 1: in every direction, there could be a black ditch kind
40:55
Speaker 1: of surrounding the universe. It's finite there they're would be,
41:00
Speaker 1: but it would have to be enough stuff after inflation
41:03
Speaker 1: for those things to happen. All right, Well, then what
41:05
Speaker 1: the answer is why didn't the Big Bang become a
41:08
Speaker 1: giant black hole? Is that there was just too much
41:10
Speaker 1: stuff and space. What this was expanding too fast? Yes,
41:13
Speaker 1: space was expanding too fast, which makes it hard to
41:16
Speaker 1: form black holes. And you need over densities of stuff,
41:19
Speaker 1: not just density. You need over density. You have to
41:22
Speaker 1: have more than your neighbors. You don't have to just
41:24
Speaker 1: have a lot of stuff. Does that mean I can
41:26
Speaker 1: sort of kill a black hole if I expand the
41:28
Speaker 1: space it's in fast enough. That's something we don't understand.
41:31
Speaker 1: We don't think so. We think once the black hole
41:33
Speaker 1: is formed, it's impossible to like dark energy expandify it.
41:37
Speaker 1: We talked about this on the podcast. Once you know,
41:39
Speaker 1: like could you shoot dark energy into a black hole
41:42
Speaker 1: and destroy it? We don't know what would happen because
41:44
Speaker 1: we don't really understand this whole expansion of space thing.
41:47
Speaker 1: We don't know how that interacts with the black hole
41:49
Speaker 1: that's already made. Right, All right, Well, I think that
41:52
Speaker 1: answer is a question for Charles. Thank you for asking
41:55
Speaker 1: the question. And I think it's sort of interesting how
41:57
Speaker 1: where people's curiosity is going with these questions. You know,
42:01
Speaker 1: you know, I feel like these questions are extrapolating from
42:04
Speaker 1: things that we've talked about or they've learned, and it's
42:07
Speaker 1: these are like next level questions. Yeah, these are attempts
42:09
Speaker 1: to fit the ideas together, which is exactly what you
42:12
Speaker 1: should be doing. You want to understand the whole universe.
42:14
Speaker 1: You don't want to just understand this piece and that piece.
42:16
Speaker 1: You want to have one unified understanding of the universe,
42:19
Speaker 1: and that requires you to take this idea you heard
42:22
Speaker 1: here and ask why doesn't that apply in this other situation,
42:25
Speaker 1: or how does that make sense given this other thing
42:27
Speaker 1: I know? And that's how you build together a working
42:29
Speaker 1: knowledge of the whole universe. So keep doing it and
42:32
Speaker 1: keep asking us questions if it doesn't make sense to you.
42:35
Speaker 1: So congrats to Meredith Hunter and Charles for stumping a physicist,
42:40
Speaker 1: which gives us great stuff to talk about on the podcast.
42:42
Speaker 1: So thanks very much. You send your prize, But you know,
42:44
Speaker 1: I think that's against the social discas, that's right, So
42:48
Speaker 1: if you have questions about the universe or things you'd
42:50
Speaker 1: like us to talk about, please do send them to
42:52
Speaker 1: us at Questions at Daniel and Jorge dot com you.
42:55
Speaker 1: Hope you enjoyed that. See you next time, YEA. Thanks
43:05
Speaker 1: for listening and remember that Daniel and Jorge Explain the
43:08
Speaker 1: Universe is a production of I heart Radio. For more
43:11
Speaker 1: podcast from my heart Radio, visit the i heart Radio app,
43:15
Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.