Latest / Daniel and Kelly’s Extraordinary Universe / Could black holes be making the Universe expand faster?

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Could black holes be making the Universe expand faster? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, Daniel, have you been keeping up with the science
• 0:10
  Speaker 1: news headlines? Oh? What does that mean? What do you mean? Oh,
• 0:15
  Speaker 1: I'm guessing there was some new clickbait article about how
• 0:18
  Speaker 1: scientists mate bananas go faster than light or something crazy.
• 0:21
  Speaker 1: They have you eat them faster than light. But that's
• 0:26
  Speaker 1: not news. Well they are kind of slippery. But are
• 0:29
  Speaker 1: you saying that we shouldn't trust science headlines? You think
• 0:32
  Speaker 1: it's fake news? Well, you know, sometimes the headlines don't
• 0:35
  Speaker 1: reflect within the article, and sometimes the news article doesn't
• 0:38
  Speaker 1: reflect the actual research that's been done, and sometimes the
• 0:42
  Speaker 1: research itself it's questionable. We Oh, you're saying even peer
• 0:46
  Speaker 1: reviewed papers can be wrong. What can we trust? Then
• 0:50
  Speaker 1: you can trust podcasters, I guess I hope all podcasters,
• 0:56
  Speaker 1: even the ones that make tales of sasquatch. All right,
• 0:59
  Speaker 1: you can trust us, Just trust us, well you us,
• 1:03
  Speaker 1: I mean, I'm a cartoonist. Padn't trust me with physics verification?
• 1:07
  Speaker 1: Then you got to listen to the podcast Learn Physics
• 1:09
  Speaker 1: so you can figure it out for yourself. Trust yourself. Oh,
• 1:13
  Speaker 1: I see this is now a self improvement podcast. Hi.
• 1:32
  Speaker 1: Am Jorheme, a cartoonists and the creator of PhD comics. Hi,
• 1:35
  Speaker 1: I'm Daniel. I'm a particle physicist and a professor you
• 1:38
  Speaker 1: see Irvine, and I do believe that learning physics is
• 1:41
  Speaker 1: a form of self improvement. Well, it depends on what
• 1:43
  Speaker 1: kind of physics, doesn't it. How about the physics of
• 1:46
  Speaker 1: eating fatty foods? And Yeah, the more you understand it,
• 1:49
  Speaker 1: the better you are informed, and the more educated choices
• 1:52
  Speaker 1: you can make. Yeah, but educated choices in this stally
• 1:55
  Speaker 1: meaning it's the right. I know potato chips aren't good
• 1:58
  Speaker 1: for you, but I still eat him. And you'd rather
• 2:01
  Speaker 1: eat them and not know that they're not good for you? Huh? Yeah,
• 2:03
  Speaker 1: maybe maybe that might help my self improvement. It might
• 2:08
  Speaker 1: help yourself enlargement. Yeah, my happiness. Oh wait, did you
• 2:11
  Speaker 1: mean something else to each of their own chip? But anyways,
• 2:16
  Speaker 1: Welcome to our podcast, Daniel and Jorge Explain the Universe,
• 2:19
  Speaker 1: a production of iHeartRadio in which we try to help
• 2:22
  Speaker 1: you on your journey of self improvement by teaching you
• 2:25
  Speaker 1: everything we do and do not know about the universe.
• 2:28
  Speaker 1: We also help you on your journey of mental self
• 2:31
  Speaker 1: enlargement as we try to grow your brain in your
• 2:34
  Speaker 1: mind and fit more understanding of the universe into it.
• 2:38
  Speaker 1: Because the universe is big and filled with mysteries and
• 2:41
  Speaker 1: all sorts of things that we have and have not
• 2:44
  Speaker 1: figured out, things that future physicists, maybe one of you
• 2:47
  Speaker 1: out there will figure out one day. Yeah, because it
• 2:50
  Speaker 1: is an amazing universe, one that is always expanding, it seems,
• 2:54
  Speaker 1: with all kinds of interesting knowledge and interesting phenomena to study,
• 2:57
  Speaker 1: to wonder about, to ask questions about, and also to
• 3:01
  Speaker 1: crime into your brain. And it seems like every single
• 3:03
  Speaker 1: day we're learning something that science has figured out. They've
• 3:06
  Speaker 1: done a new study on banana slugs, or they've done
• 3:09
  Speaker 1: a new study on bananas. There's a huge population and
• 3:11
  Speaker 1: scientists out there doing studies, learning things about the universe
• 3:15
  Speaker 1: and putting them out there in papers. Well, that's kind
• 3:17
  Speaker 1: of what you would expect, right, I mean, scientists aren't
• 3:20
  Speaker 1: working all the time and they should becoming up Whitney results, right,
• 3:23
  Speaker 1: Otherwise what are they doing exactly? And it's a wonderful,
• 3:26
  Speaker 1: delicious fountain of knowledge that science is creating. And that
• 3:30
  Speaker 1: knowledge is not just for other scientists, it's for everybody.
• 3:34
  Speaker 1: We all want to know. What are the answers to
• 3:36
  Speaker 1: the deep mysteries of the universe? How fast is it expanding?
• 3:39
  Speaker 1: What's inside black holes? How did our solar system get
• 3:42
  Speaker 1: to be the way that it is. So it's not
• 3:45
  Speaker 1: just other physics professors who read the writings of physics professors.
• 3:48
  Speaker 1: It's everybody out there who wants to know the answers
• 3:51
  Speaker 1: to these big questions. Yeah, sometimes what scientists discover gets
• 3:55
  Speaker 1: into the news media and out there into the general population.
• 3:58
  Speaker 1: But I feel like it's it's kind of a filter though,
• 4:01
  Speaker 1: Like only the juicy headlines make it out there into
• 4:04
  Speaker 1: the big newspapers. It is a bit of a mystery
• 4:07
  Speaker 1: to me what gets covered. I mean, I read a
• 4:09
  Speaker 1: lot of physics papers, and then sometimes I'll read a
• 4:12
  Speaker 1: popular article about one, and I'll think, like, why did
• 4:14
  Speaker 1: this one get chosen to make a big deal about
• 4:17
  Speaker 1: It's not really that big a deal, but you know,
• 4:19
  Speaker 1: you can take some little aspect of it and make
• 4:21
  Speaker 1: it sound like it's a really big deal, because most
• 4:24
  Speaker 1: people out there don't understand a bigger picture of the field.
• 4:27
  Speaker 1: Is this really a big step forward or is it
• 4:28
  Speaker 1: a tiny little increment? And we're just hearing about the
• 4:31
  Speaker 1: overall motivation for this entire line of research. So it's
• 4:34
  Speaker 1: hard when you're not an expert to really understand what
• 4:37
  Speaker 1: was a breakthrough and what wasn't. Well, I don't think
• 4:39
  Speaker 1: it's a big mystery. There's probably a science reporter out
• 4:42
  Speaker 1: there that needs to also work to write something on
• 4:47
  Speaker 1: a deadline. Probably, Yeah, I guess you got to pick
• 4:49
  Speaker 1: something to trumpet about. That's the job. The really good articles, though,
• 4:53
  Speaker 1: do put things in context. They talk to experts, or
• 4:55
  Speaker 1: they are written by experts, so the reader can really
• 4:57
  Speaker 1: get a sense of is this a huge, huge leap
• 5:00
  Speaker 1: forward or is this just promising potential breakthroughs or what's
• 5:04
  Speaker 1: really going on? Well, it seems like there's a interesting
• 5:07
  Speaker 1: science headlines every other week, But I guess sometimes people
• 5:10
  Speaker 1: need a little bit of help figuring out which ones
• 5:12
  Speaker 1: are a big deal and which ones are maybe a
• 5:15
  Speaker 1: little bit, you know, over enthusiastically reported on by the reporter.
• 5:20
  Speaker 1: If you just believe all the headlines that you read,
• 5:22
  Speaker 1: you would think that every couple of weeks there's a
• 5:24
  Speaker 1: result that's going to change fundamentally the way science works.
• 5:27
  Speaker 1: That like, science is going to pivot on this result
• 5:30
  Speaker 1: that that we'll look back on history and say, wow,
• 5:32
  Speaker 1: there was a time before and after we knew this
• 5:35
  Speaker 1: one fact in reality, though, a lot of times you'll
• 5:38
  Speaker 1: read about something which sounds like a big deal, and
• 5:40
  Speaker 1: then you'll never hear about it again, which tells you like,
• 5:43
  Speaker 1: maybe it wasn't really that big a deal. So it's
• 5:45
  Speaker 1: hard to sift through and figure out like which ones
• 5:47
  Speaker 1: historically are actually going to seem like pivot moments in
• 5:51
  Speaker 1: history and which ones are just going to have sort
• 5:53
  Speaker 1: of filled the news cycle for that week. But I
• 5:56
  Speaker 1: feel like that's kind of maybe one of the exciting
• 5:58
  Speaker 1: things about science. You know, this idea that establish ideas
• 6:01
  Speaker 1: can be overturned at any moment, and you know, everyone's
• 6:05
  Speaker 1: working on a big idea of their own, you know,
• 6:07
  Speaker 1: because we haven't figured things out, and so everyone has
• 6:09
  Speaker 1: a different angle on it, and any focus that anyone
• 6:11
  Speaker 1: makes could potentially, in reality, overturn what we know. Right,
• 6:15
  Speaker 1: You're absolutely right, And it's tempting to look back on
• 6:18
  Speaker 1: history and say, oh, there was an obvious line, a
• 6:21
  Speaker 1: step from A to B to C to D, and
• 6:23
  Speaker 1: that's how we got to where we are. But when
• 6:26
  Speaker 1: you're in the moment, you don't know which direction is
• 6:28
  Speaker 1: going to bear fruit and which one isn't. The true
• 6:31
  Speaker 1: history of science is sort of like a big branching
• 6:33
  Speaker 1: tree where lots of those branches were later abandoned or
• 6:36
  Speaker 1: died off, and when you're at the tip of the
• 6:38
  Speaker 1: latest branch, you don't necessarily know which direction to go.
• 6:41
  Speaker 1: So that's why people are exploring in lots of different
• 6:44
  Speaker 1: directions and exclaiming excitedly when they figure out something cool.
• 6:47
  Speaker 1: That might mean that this is the future path of
• 6:50
  Speaker 1: all of science. But maybe it's not. Maybe it just
• 6:53
  Speaker 1: dies off after the next branch. You're right, we never
• 6:55
  Speaker 1: do know in the moment. Yeah, you don't want to
• 6:57
  Speaker 1: be that reporter who finds out about something amazing Indensis man,
• 7:02
  Speaker 1: this was an okay result. Yeah, that's true. But it
• 7:04
  Speaker 1: also means that you do need to read all these
• 7:07
  Speaker 1: articles with a grain of salt, and sometimes a spoonful
• 7:09
  Speaker 1: of salt. It seems like, for example, a recent headline
• 7:14
  Speaker 1: that's made the rounds that everyone seems to be very
• 7:16
  Speaker 1: excited about, you've got a lot of questions about it. Yes,
• 7:20
  Speaker 1: there was an article last week that lots of people
• 7:23
  Speaker 1: read and thought, oh my gosh, this seems like a
• 7:25
  Speaker 1: really big deal. I wonder if it's true, And they
• 7:29
  Speaker 1: sent it to me, so I got dozens of emails
• 7:31
  Speaker 1: from listeners and tweets from people asking me, is this
• 7:34
  Speaker 1: for real? What do you think? It seems like it
• 7:37
  Speaker 1: would be more efficient if all reporters just ask you
• 7:40
  Speaker 1: every time they write a science article, and then you
• 7:43
  Speaker 1: could just, you know, impart your judgment. Well you know
• 7:46
  Speaker 1: that happened. Sometimes they do reach out to me to
• 7:48
  Speaker 1: ask me for comment, and reporters out there email me.
• 7:51
  Speaker 1: I actually write back. I'd be happy to comment on
• 7:54
  Speaker 1: research articles. I don't know do they want, Maybe they
• 7:57
  Speaker 1: don't want. Maybe they don't if you're trying to get
• 8:01
  Speaker 1: readers to read their headlines and click through. And now
• 8:04
  Speaker 1: for a splash of cold water. Daniel Whites, Well, the
• 8:06
  Speaker 1: article that came out, it does sound pretty interesting. That
• 8:08
  Speaker 1: has to do with black holes and the expansion of
• 8:11
  Speaker 1: the universe. So today on the podcast, we'll be asking
• 8:14
  Speaker 1: the question, good black holes be making the universe expand faster?
• 8:24
  Speaker 1: Black holes and dark energy too great taste? That tastes
• 8:28
  Speaker 1: great together? Do they? Man? I feel like it's like
• 8:31
  Speaker 1: black holes versus dark energy. It's like Emperor Popatine fighting
• 8:35
  Speaker 1: Darth the It sounds to me like the last round
• 8:39
  Speaker 1: of the Battle of the Bands. Yeah, there you go.
• 8:41
  Speaker 1: We can just sit back with some popcorn and watch
• 8:44
  Speaker 1: what happens. I think black holes and dark energy they've
• 8:49
  Speaker 1: gotta be like metal bands or sort of like goth
• 8:51
  Speaker 1: rock or something. Yeah, I'm sure there are grows up
• 8:54
  Speaker 1: there with those names. But this is an interesting question
• 8:56
  Speaker 1: because at first hearing it kind of sounds kind of intuitive, right,
• 8:59
  Speaker 1: like black holes suck stuff in, they make things more compact,
• 9:02
  Speaker 1: and ye, how can they be making the universe expand faster? Exactly?
• 9:07
  Speaker 1: So it's got all the elements of a huge scientific
• 9:10
  Speaker 1: revolution and big splash in the news. Right, it's counterintuitive,
• 9:15
  Speaker 1: and it solves more than one mystery, like what's going
• 9:18
  Speaker 1: on with black holes and what's going on with dark energy?
• 9:21
  Speaker 1: Oh my gosh, maybe one explains the other. So it's
• 9:25
  Speaker 1: very tantalizing. Yeah, it's always exciting when there's like a
• 9:27
  Speaker 1: crossover event, right, like Marvel and DC, like Superman and
• 9:31
  Speaker 1: Spiderman working together or against each other making the universe faster.
• 9:36
  Speaker 1: It's like combining two tasty sandwiches. You know, peanut butter
• 9:38
  Speaker 1: sandwich is good, a ruben is good. Would a Ruben
• 9:41
  Speaker 1: with peanut butter be even better? Well, until you do
• 9:46
  Speaker 1: the experiment, you can't know for sure, right, Daniel, you're
• 9:48
  Speaker 1: going to do that experiment? You know, if I was
• 9:50
  Speaker 1: a lunch eating kind of person, I might, but I'll
• 9:52
  Speaker 1: have to leave it to you. I'll pass. I don't.
• 9:55
  Speaker 1: I don't think I need to know that the result
• 9:59
  Speaker 1: listeners let us know. But it's interesting. So this paper
• 10:02
  Speaker 1: came out last week right as of this recording. It did,
• 10:05
  Speaker 1: and it's set the physics world of buzz all sorts
• 10:08
  Speaker 1: of cosmologists and experts in black holes and in dark energy.
• 10:12
  Speaker 1: We're arguing about whether this paper made any sense and
• 10:15
  Speaker 1: what it meant and whether we could believe it. Oh right,
• 10:17
  Speaker 1: because there are experts in both areas and this one
• 10:21
  Speaker 1: try to put them together. Did they ask for a
• 10:23
  Speaker 1: permission or you don't need to ask for permission to
• 10:27
  Speaker 1: write a paper. You can just write it and send
• 10:28
  Speaker 1: it out there and see if people will read it.
• 10:31
  Speaker 1: Why can it They need permission to publish a paper,
• 10:33
  Speaker 1: thoughn't you? It requires the whole committee to approve your paper.
• 10:38
  Speaker 1: To be approved, you definitely need reviewers and all that
• 10:40
  Speaker 1: kind of stuff. But you can just write a paper
• 10:42
  Speaker 1: and put it on the archive and you know people
• 10:44
  Speaker 1: will read it. These days, journal review is sort of
• 10:46
  Speaker 1: a secondary process. People read papers well before they're ever
• 10:49
  Speaker 1: reviewed by journals. Wait wait, wait, wait what you can
• 10:52
  Speaker 1: just post things on the internet without permission. Yeah, this
• 10:54
  Speaker 1: is a site called archive dot org where all physicists
• 10:57
  Speaker 1: post their papers before they go to the journals, because
• 11:00
  Speaker 1: the journals take forever to review stuff, and you want
• 11:02
  Speaker 1: people to read your results basically as soon as they're ready.
• 11:05
  Speaker 1: So these days most of the actual science happens on
• 11:07
  Speaker 1: what we call preprints, where people post their papers before
• 11:11
  Speaker 1: they go to the journals. Wow, that sounds like having
• 11:14
  Speaker 1: a policy debate over Twitter comments. You wait until you
• 11:20
  Speaker 1: checked it out first, or maybe that is sort of
• 11:22
  Speaker 1: a now part of the process of experts checking it out,
• 11:24
  Speaker 1: you put it out to the whole community. Yeah, there's
• 11:27
  Speaker 1: actually a vigorous debate about whether we even need journals
• 11:30
  Speaker 1: anymore now that we have the Internet. Journals aren't necessary
• 11:33
  Speaker 1: for actually publishing and distributing papers. You just have them online,
• 11:37
  Speaker 1: so they're really just there to provide peer review. But
• 11:40
  Speaker 1: you know, there's a lot of question about whether peer
• 11:42
  Speaker 1: review actually adds anything to papers, or if it just
• 11:45
  Speaker 1: delays them and burdens a bunch of people with extra work.
• 11:48
  Speaker 1: I guess that feels a little risky. I mean that's
• 11:50
  Speaker 1: sort of like calling Twitter comments peer review or like
• 11:53
  Speaker 1: the like bunds, like, oh, this paper got two thousand likes,
• 11:56
  Speaker 1: it must be true. Well, I never read and believe
• 11:59
  Speaker 1: a paper just as it's been peer reviewed. I'm going
• 12:01
  Speaker 1: to read it myself and see if it makes sense anyway.
• 12:04
  Speaker 1: All right, Well, fortunately people out there have us, or
• 12:07
  Speaker 1: at least they have you, to go through papers like
• 12:09
  Speaker 1: this one to see if it makes sense, and they,
• 12:12
  Speaker 1: I guess they have me to ask you about it.
• 12:14
  Speaker 1: That's my role exactly. And so this paper was a
• 12:16
  Speaker 1: lot of fun to read and to talk to my
• 12:18
  Speaker 1: colleagues about. And I also went out there to gather
• 12:21
  Speaker 1: opinions from random people I ran into on the UC
• 12:24
  Speaker 1: Irvine campus. Yeah, because as usual, we're wondering how many
• 12:27
  Speaker 1: people out there I had heard about this paper or
• 12:30
  Speaker 1: had an opinion about whether black holes can make the
• 12:32
  Speaker 1: universe grow faster. Usually people had to say that's not
• 12:36
  Speaker 1: my area of expertise. My understanding was like they're an
• 12:40
  Speaker 1: energy sync though, like the energy goes like it's like
• 12:44
  Speaker 1: the one place where matter could possibly no one like
• 12:47
  Speaker 1: actually be destroyed. So I'm not sure how to answer
• 12:52
  Speaker 1: that question, but my guests would be the negative or
• 12:54
  Speaker 1: it would do the opposite. But again I'm not I
• 12:58
  Speaker 1: guess that would be an astrophysicist would be their expertise.
• 13:01
  Speaker 1: I don't know. I don't really know much about black holes,
• 13:03
  Speaker 1: and so I'm assuming maybe I wouldn't think so, because
• 13:07
  Speaker 1: like black holes are meant to like go inwards right
• 13:11
  Speaker 1: like almost like a funnel, and it's they seem to
• 13:14
  Speaker 1: be pulling things in, So I would almost expect the opposite,
• 13:18
  Speaker 1: where it would like help fast forward the I don't
• 13:21
  Speaker 1: know when everything condenses. That's my opinion, at least. I'm
• 13:26
  Speaker 1: not a physics I don't know. So I was actually
• 13:28
  Speaker 1: just reading this paper last week. I think it's a
• 13:32
  Speaker 1: really interesting result, you know. I think the media has
• 13:34
  Speaker 1: maybe blown it a little bit out of proportion and
• 13:36
  Speaker 1: portrayed it in a way that I don't think it's
• 13:39
  Speaker 1: one hundred percent accurate. However, I do think there is
• 13:42
  Speaker 1: always interesting. I think what they're doing in the paper,
• 13:45
  Speaker 1: looking at sort of black holes as a different type
• 13:48
  Speaker 1: of energy source to drive the expansion, is a really
• 13:52
  Speaker 1: cool idea. So yes, I think it's possible, but maybe
• 13:56
  Speaker 1: not in the way that's been portrayed by the media. Wow. Okay,
• 13:58
  Speaker 1: I don't know, but since the universe is expanding and
• 14:03
  Speaker 1: black holes are part of it, I'm gonna go with yes. No,
• 14:05
  Speaker 1: I don't think black holes is gonna mat of his
• 14:07
  Speaker 1: expand because they sucked things towards them with some gravity,
• 14:12
  Speaker 1: so they wouldn't be pushing things away and expand. They
• 14:14
  Speaker 1: would if anything decreases as the universe. I didn't read
• 14:18
  Speaker 1: science or would probably referred to, so I'm not really sure.
• 14:20
  Speaker 1: In my black hole compressed as a matter, So I
• 14:22
  Speaker 1: I'm not sure how it would expand any universe. Oh.
• 14:25
  Speaker 1: I don't really know much about black holes, so I
• 14:27
  Speaker 1: don't really know it sounds plausible to you at all? Yeah,
• 14:30
  Speaker 1: I mean, I guess all right. Most people had not
• 14:34
  Speaker 1: heard of the article, although I was surprised that one
• 14:36
  Speaker 1: person had just read that paper. Were you like what
• 14:40
  Speaker 1: or did you ask your office mate or one of
• 14:42
  Speaker 1: your grad students. I didn't have a whole lot of time,
• 14:44
  Speaker 1: so I was wandering around the physics portion of the campus,
• 14:47
  Speaker 1: and I'm pretty sure I did hit an astrophysics grad
• 14:50
  Speaker 1: student who had actually read the paper. Oh, I see
• 14:53
  Speaker 1: this is a little bit loaded of a sample. My
• 14:55
  Speaker 1: favorite response was a person who suggests that I go
• 14:58
  Speaker 1: and ask a physicist for an answer. That sounds like
• 15:04
  Speaker 1: a very sensible thing to do. Why didn't you just
• 15:06
  Speaker 1: ask a physicist, Daniel, Yeah, good question exactly. Maybe I should.
• 15:11
  Speaker 1: I should go get a PhD in physics and I
• 15:13
  Speaker 1: should go figure this out myself. You should be like
• 15:15
  Speaker 1: a professor or something, and then you can answerr questions
• 15:18
  Speaker 1: for a living. Yeah. I think that person misunderstood what
• 15:20
  Speaker 1: I was trying to do with my question. I think
• 15:22
  Speaker 1: she thought I was wandering around campus looking for somebody
• 15:25
  Speaker 1: to explain this paper to me. Oh, I see, I see. Well,
• 15:29
  Speaker 1: I guess there aren't that many people walking around asking
• 15:32
  Speaker 1: physics questions. Did you think maybe you were like somebody
• 15:35
  Speaker 1: lost on campus. Yeah, you know, it's famously hard to
• 15:37
  Speaker 1: tell physicists apart from homeless people, and so I think
• 15:40
  Speaker 1: maybe she would just being polite and patronizing me. Well,
• 15:43
  Speaker 1: it's an interesting paper, and so let's dig into it.
• 15:45
  Speaker 1: What does the paper say? So, in a nutshell, the
• 15:48
  Speaker 1: paper says that black holes out there in the universe
• 15:53
  Speaker 1: are the source of dark energy, that they are the
• 15:56
  Speaker 1: reason that the universe's expansion is accelerating. That the expansion
• 16:01
  Speaker 1: of the universe is getting faster and faster every year.
• 16:03
  Speaker 1: That's the basic idea of the paper. That sounds pretty cool.
• 16:06
  Speaker 1: All Right, we're done. I'm off to have a peanut
• 16:11
  Speaker 1: butter ribbon sandwich. Yeah, I'm kind of hungry. I prefer
• 16:16
  Speaker 1: almond butter. All right, good to know. We might have
• 16:20
  Speaker 1: to do a side experiment on that. But let's maybe
• 16:22
  Speaker 1: break it down for people, and let's start with just
• 16:24
  Speaker 1: the idea that the universe is expanding. Some people might
• 16:28
  Speaker 1: not know that the universe is getting bigger and bigger,
• 16:30
  Speaker 1: and it's getting bigger at a faster and faster rate. Yeah.
• 16:33
  Speaker 1: This phenomenon goes by the name of dark energy, which
• 16:36
  Speaker 1: is a very mysterious sounding name for something we don't
• 16:39
  Speaker 1: really understand very well. But we do know some things,
• 16:43
  Speaker 1: Like we look out there into the universe and we
• 16:45
  Speaker 1: watch galaxies. We measure their velocity relative to us by
• 16:49
  Speaker 1: looking at how the light from them is red shifted,
• 16:52
  Speaker 1: because things that are moving away from us faster will
• 16:55
  Speaker 1: have the wavelengths of their light stretched out longer and longer.
• 16:58
  Speaker 1: We call that red shifting. And we look out into
• 17:00
  Speaker 1: the universe, and as we look out further and further,
• 17:02
  Speaker 1: we're looking further back in time because it takes time
• 17:06
  Speaker 1: to get here. So we can see how fast things
• 17:08
  Speaker 1: are moving away from us now the close up stuff,
• 17:11
  Speaker 1: and how fast things were moving away from us earlier.
• 17:13
  Speaker 1: So we can see sort of how much this is
• 17:15
  Speaker 1: changing our things moving away from us faster and faster
• 17:18
  Speaker 1: every year, or is it slowing down? And about twenty
• 17:21
  Speaker 1: years ago we went out and did this measurement using
• 17:24
  Speaker 1: very precise techniques involving supernovas and exactly how they blow
• 17:27
  Speaker 1: up and all that stuff, and we found something very surprising.
• 17:31
  Speaker 1: We discovered that the universe is expanding, and that expansion
• 17:34
  Speaker 1: is speeding up, meaning that every year galaxies out there
• 17:38
  Speaker 1: are moving away from us faster and faster. And so
• 17:41
  Speaker 1: that's what we call dark energy. We don't know what's
• 17:44
  Speaker 1: doing it, we don't understand the mechanism for it, but
• 17:47
  Speaker 1: we see that this is happening, and we want to
• 17:49
  Speaker 1: understand it. Yeah, and you call it dark energy because
• 17:52
  Speaker 1: it's kind of like an energy, right, Like it requires
• 17:54
  Speaker 1: work and energy to make the universe bigger, because you're
• 17:58
  Speaker 1: sort of creating more and more space. That's right, and
• 18:00
  Speaker 1: we are making more space between galaxies actually everywhere in
• 18:04
  Speaker 1: the universe. We think that space itself is expanding. So
• 18:08
  Speaker 1: if you have your picture in your mind of the
• 18:10
  Speaker 1: universe's expansion is sort of like a bomb with a
• 18:13
  Speaker 1: tiny little dot at the center that blows up and
• 18:15
  Speaker 1: everything flies through space, you should try instead to think
• 18:18
  Speaker 1: about it as like a universe already filled with stuff,
• 18:21
  Speaker 1: which then expands, creating new space between everything in the
• 18:25
  Speaker 1: universe all over the place. So it's sort of like
• 18:28
  Speaker 1: this stretching of space or this expansion of space itself.
• 18:31
  Speaker 1: And you're right, that makes more energy because we think
• 18:34
  Speaker 1: that every chunk of space comes with energy, and that
• 18:38
  Speaker 1: energy then drives the expansion, which makes more space, which
• 18:41
  Speaker 1: drives the expansion even more. And so that's why it's accelerating,
• 18:44
  Speaker 1: sort of like taken off. And then it's called dark
• 18:47
  Speaker 1: because there's no visible evidence of it in a way,
• 18:51
  Speaker 1: right like this, like everything's glowing or something, or there's
• 18:54
  Speaker 1: some kind of explosion that you can see. It's like
• 18:56
  Speaker 1: an invisible force that's growing the universe. It is invisible.
• 19:01
  Speaker 1: But I think probably it's called dark because it's mysterious,
• 19:03
  Speaker 1: because we don't understand it. It's like unexplained. It's an
• 19:07
  Speaker 1: area we have yet to illuminate. So I think it's
• 19:10
  Speaker 1: sort of like mentally dark more than physically dark, though
• 19:14
  Speaker 1: also invisible. You know. We call it dark energy, which
• 19:17
  Speaker 1: suggests that it's like a thing we understand is something
• 19:20
  Speaker 1: in physics. It's happening, but really we don't understand where
• 19:23
  Speaker 1: this comes from. It's something we see happening in the
• 19:25
  Speaker 1: universe and we can describe in some ways using our theories,
• 19:30
  Speaker 1: but we don't know really where it comes from at all. Yeah,
• 19:33
  Speaker 1: it's a big mystery, maybe even the biggest mystery in
• 19:35
  Speaker 1: the universe, right is it's a mystery that kind of
• 19:37
  Speaker 1: permeates the entire universe, and the universe is pretty big.
• 19:41
  Speaker 1: It definitely dominates the universe. Like, if you add up
• 19:44
  Speaker 1: how much energy it takes to make this happen, it's
• 19:47
  Speaker 1: like seventy percent of the energy in the universe. So
• 19:50
  Speaker 1: you take a cubic light year of space, for example,
• 19:53
  Speaker 1: and you say how much energy is stored in like
• 19:54
  Speaker 1: all the gas and the stars and the planets. That's
• 19:57
  Speaker 1: like five percent of the energy in that cube. Another
• 20:00
  Speaker 1: twenty five ish percent is dark batter that also has
• 20:04
  Speaker 1: energy in it and the rest of its seventy percent
• 20:06
  Speaker 1: of the energy budget of the universe. Is this weird stuff,
• 20:09
  Speaker 1: dark energy that's causing the universe to expand faster and
• 20:13
  Speaker 1: faster every year. But again we don't really know why
• 20:16
  Speaker 1: it's happening or where it comes from. We can describe
• 20:19
  Speaker 1: it in our theories, like we have general relativity that
• 20:22
  Speaker 1: tells us how the universe works and how space works
• 20:25
  Speaker 1: and how it can expand, and there is an option
• 20:27
  Speaker 1: in general relativity to make this kind of thing happen. Yeah,
• 20:30
  Speaker 1: you have some theories that it maybe is like a
• 20:33
  Speaker 1: property of space itself, like space itself is potential energy
• 20:37
  Speaker 1: and it can't help itself but to get bigger. That's right.
• 20:40
  Speaker 1: And remember that while general relativity is a theory of gravity,
• 20:43
  Speaker 1: and we tend to usually think of gravity is like
• 20:45
  Speaker 1: something that attracts stuff. Are you're attracted to the Earth,
• 20:48
  Speaker 1: the Earth is attracted to the Sun, And we think
• 20:51
  Speaker 1: of general relativities like explaining that kind of stuff, that
• 20:54
  Speaker 1: gravity is purely attractive. General relativity is more complex than that.
• 20:57
  Speaker 1: It's not just like how much mass and energy is
• 21:00
  Speaker 1: there in a certain place. It also depends on the
• 21:02
  Speaker 1: distribution of that mass and energy, and also on the
• 21:04
  Speaker 1: kind of energy. So example, if you have a lot
• 21:07
  Speaker 1: of potential energy in a part of space, it can
• 21:10
  Speaker 1: generate a negative pressure, it can cause the expansion of
• 21:13
  Speaker 1: that space. So Einstein's equations of all these different kind
• 21:17
  Speaker 1: of knobs that can make space do different kinds of things.
• 21:19
  Speaker 1: So if you say, well, space might have a lot
• 21:21
  Speaker 1: of potential energy into it, you add this thing we
• 21:23
  Speaker 1: call the cosmological constant, where all of space just has
• 21:27
  Speaker 1: this potential energy in it that can actually cause this
• 21:29
  Speaker 1: kind of expansion. Then of course you can ask like, well,
• 21:32
  Speaker 1: why would it have this cosmological constant? Where is this
• 21:35
  Speaker 1: potential energy coming from? And that's sort of where we are.
• 21:39
  Speaker 1: That would be sort of a very deep question about
• 21:42
  Speaker 1: the very nature of space, right. That's right, as you
• 21:45
  Speaker 1: say space we think has energy in it, Like we
• 21:47
  Speaker 1: know that space has quantum fields inside of it. Right,
• 21:50
  Speaker 1: There's a field for the electron on, a field for
• 21:52
  Speaker 1: the Higgs boson, and a field for the photon. It
• 21:54
  Speaker 1: has all these fields in it, and those fields have
• 21:56
  Speaker 1: some potential energy. We know that because they're quantum fields
• 22:00
  Speaker 1: can't relax all the way down to zero energy, and
• 22:02
  Speaker 1: so for a while, people thought, oh, maybe that's it.
• 22:05
  Speaker 1: Maybe all the fields that are out there in space
• 22:07
  Speaker 1: they have this potential energy, and that potential energy was
• 22:10
  Speaker 1: causing the expansion of the universe. So people sat down
• 22:12
  Speaker 1: to try to calculate it and say, well, how much
• 22:15
  Speaker 1: potential energy is there in all of those fields, and
• 22:17
  Speaker 1: how much potential energy would you need to explain this
• 22:20
  Speaker 1: expansion of the universe to provide the potential energy that
• 22:23
  Speaker 1: will allow general relativity to drive the universe expanding this way.
• 22:28
  Speaker 1: So you sit down and calculate those two numbers, and
• 22:30
  Speaker 1: you hope they agree, because that would mean that it's
• 22:33
  Speaker 1: an explanation. But instead they disagree, and they disagree not
• 22:36
  Speaker 1: by a little bit, but by a number like ten
• 22:39
  Speaker 1: to the hundred and twenty. So like, we really just
• 22:42
  Speaker 1: don't understand this at all. Yeah, it's a big mystery.
• 22:45
  Speaker 1: And so the universe is expanding faster and faster and
• 22:48
  Speaker 1: we don't know why. And then now this paper is
• 22:50
  Speaker 1: kind of saying that maybe black holes are the source
• 22:53
  Speaker 1: of that expansion, and so let's get into what exactly
• 22:56
  Speaker 1: black holes are and how they might be fueling dark energy.
• 23:00
  Speaker 1: But first let's take a quick break, all right, we
• 23:15
  Speaker 1: are playing MythBusters today kind of news headlines with papers
• 23:21
  Speaker 1: that have been published. There's been a paper recently that
• 23:24
  Speaker 1: has a pretty juicy headline that says that or that
• 23:27
  Speaker 1: asks the question whether black holes can be making the
• 23:29
  Speaker 1: universe expand faster? Now, Daniel, is this a paper that
• 23:31
  Speaker 1: just dropped on the internet or is this a paper
• 23:33
  Speaker 1: that has already been peer reviewed. This is a paper
• 23:36
  Speaker 1: that has been peer reviewed. These guys did not drop
• 23:39
  Speaker 1: it on the Internet before they sent it to reviewers,
• 23:42
  Speaker 1: so they kept a little bit tight to their chest.
• 23:44
  Speaker 1: I think also they linked it with a bunch of
• 23:47
  Speaker 1: publicity and stuff. So sometimes people don't put their papers
• 23:50
  Speaker 1: up in the Internet before they get peer reviewed. And
• 23:52
  Speaker 1: I think that's actually more common in astronomy than it is,
• 23:56
  Speaker 1: like in particle physics. Interesting, why do you think that is?
• 23:59
  Speaker 1: Astronomers know how to play the press game a little
• 24:01
  Speaker 1: better than particle physicists, or particle physicists just like to
• 24:04
  Speaker 1: post them to the Internet. Well, particle physicists are the
• 24:06
  Speaker 1: ones who invented this whole idea of putting things on
• 24:09
  Speaker 1: the Internet. I mean, we invented the Worldwide Web. We
• 24:11
  Speaker 1: have these big international collaborations and Also, I think for
• 24:14
  Speaker 1: particle physics, by the time you have a paper ready,
• 24:17
  Speaker 1: usually it's been reviewed by like five thousand of your
• 24:20
  Speaker 1: other colleagues whose names are also on the paper, and
• 24:22
  Speaker 1: so the peer review process feels a little bit more
• 24:24
  Speaker 1: like a rubber stamp in particle physics than in other fields.
• 24:28
  Speaker 1: All right, Well, this paper that came out recently says
• 24:30
  Speaker 1: that black holes could be what's making the universe expand
• 24:32
  Speaker 1: faster and faster. And so we talked about what dark
• 24:35
  Speaker 1: energy is, what the expansion of the universe is. Now
• 24:38
  Speaker 1: let's talk a little bit about black holes, Like how
• 24:40
  Speaker 1: do you explain what a black hole is? And what
• 24:42
  Speaker 1: don't we know about them? Right? And so the takeaway
• 24:44
  Speaker 1: from dark energy is the universe is expanding, it's expanding
• 24:48
  Speaker 1: faster and faster. We don't know why that's happening because
• 24:51
  Speaker 1: we can't explain where this potential energy is coming from,
• 24:55
  Speaker 1: this sort of vacuum energy of the universe. All right,
• 24:57
  Speaker 1: So that's a huge mystery, as you said, right, big
• 25:00
  Speaker 1: not understood thing in the universe. Now, one of the
• 25:03
  Speaker 1: other really fascinatings, big misunderstood things in the universe r
• 25:07
  Speaker 1: of course black holes that we've talked about on the
• 25:09
  Speaker 1: podcast lots of times, because they're so fascinating and amazing
• 25:13
  Speaker 1: and might contain within them like secrets of the nature
• 25:16
  Speaker 1: of space and time and all sorts of crazy stuff
• 25:19
  Speaker 1: because they are very extreme situations. They are a spot
• 25:22
  Speaker 1: in space that is so dense with energy and matter
• 25:25
  Speaker 1: that space is curved so intensely that nothing can escape
• 25:30
  Speaker 1: past this event horizon. That even photons which travel at
• 25:33
  Speaker 1: the speed of light are trapped inside because space is
• 25:36
  Speaker 1: curved essentially so that it's one dimensional. Every direction forward
• 25:40
  Speaker 1: once you're inside a black hole leads towards the center
• 25:43
  Speaker 1: of the black hole, and in general relativity, it says
• 25:46
  Speaker 1: that this force is so powerful that everything inside the
• 25:48
  Speaker 1: black hole eventually collapses to the very very center, forming
• 25:52
  Speaker 1: a singularity, a dot of infinite density because there's a
• 25:56
  Speaker 1: lot of mass with zero volume. Yeah, chatted about this
• 26:00
  Speaker 1: a lot. It's interesting that for black holes it's all
• 26:03
  Speaker 1: about the density of mass, right of matter, because gravity
• 26:07
  Speaker 1: gets stronger the closer you get to it, and so
• 26:10
  Speaker 1: if you put a lot of mass in a small spot,
• 26:13
  Speaker 1: that means you can get really close to it, and
• 26:14
  Speaker 1: so at some point that gravity gets so crazy, so
• 26:17
  Speaker 1: big that it actually creates a hole in space. You're
• 26:19
  Speaker 1: exactly right. It's all about the density. Like the same
• 26:22
  Speaker 1: mass that could create a black hole if you squeezed
• 26:25
  Speaker 1: it down, could also not create a black hole. If
• 26:28
  Speaker 1: it was more spread out, like the mass of our
• 26:30
  Speaker 1: sun could create a black hole, if something squeezed it down,
• 26:34
  Speaker 1: or if the Sun stopped exploding, which is what's preventing
• 26:37
  Speaker 1: it from collapsing into something more dense. So it's not
• 26:40
  Speaker 1: just about the amount of mass, it's about the density.
• 26:43
  Speaker 1: And that means that you can have black holes of
• 26:45
  Speaker 1: all sorts of masses. You can have black holes like
• 26:47
  Speaker 1: the mass of our sun. You can have black holes
• 26:49
  Speaker 1: like ten times the mass of the sun, a billion
• 26:52
  Speaker 1: times the mass of the sun. Black holes coming in
• 26:54
  Speaker 1: a huge variety of sizes and masses. And that's one
• 26:58
  Speaker 1: of the big puzzles about black holes. Yeah, well, it's
• 27:01
  Speaker 1: maybe even stepping back a little bit. We don't actually
• 27:03
  Speaker 1: know if black holes are real, real, like we talked
• 27:06
  Speaker 1: about them like they are, but actually they are Kenneth theoretical,
• 27:09
  Speaker 1: and we have pictures of them, but we're not quite
• 27:12
  Speaker 1: sure what's in the picture. Right, that's exactly right. We
• 27:14
  Speaker 1: have a model from general relativity that predicts that this
• 27:18
  Speaker 1: would happen, and it says, if you get matter dense enough,
• 27:21
  Speaker 1: then you should create this event horizon and have a
• 27:23
  Speaker 1: singularity on the inside. And for a long time that
• 27:26
  Speaker 1: was just theoretical, and people thought, that's weird. I bet
• 27:29
  Speaker 1: something prevents that from happening. That seems too strange. But
• 27:32
  Speaker 1: then we saw these things out in the universe, and specifically,
• 27:35
  Speaker 1: what we saw were very dark portions of space that
• 27:38
  Speaker 1: had a lot of curvature to them, very strong gravity.
• 27:41
  Speaker 1: For example, we saw stars whizzing by very close and
• 27:44
  Speaker 1: getting turned around by strong gravity, but we didn't see
• 27:47
  Speaker 1: anything at that location. So we crossed off a bunch
• 27:50
  Speaker 1: of candidates. Oh maybe it's a neutron star. Nope, Oh
• 27:52
  Speaker 1: maybe it's this, maybe it's that, maybe it's the other thing,
• 27:54
  Speaker 1: And eventually the only thing left was a general relativity
• 27:58
  Speaker 1: black hole. That's the only sort of explanation we had
• 28:01
  Speaker 1: for this kind of phenomena. But it's not a direct observation, right,
• 28:05
  Speaker 1: it's not like we've seen the event horizon literally or
• 28:09
  Speaker 1: we verify that it really is a black hole. We
• 28:11
  Speaker 1: just sort of like observe things closer and closer and
• 28:14
  Speaker 1: closer to the black hole that haven't yet fallen in
• 28:16
  Speaker 1: that tell us it must be something very dense and
• 28:20
  Speaker 1: very dark, right, something super dense, super dark that doesn't shine.
• 28:24
  Speaker 1: But it could be just a dark hole, not just
• 28:26
  Speaker 1: a black hole, for example, could just be a lot
• 28:28
  Speaker 1: of mass compacted really tightly, but not necessarily a singularity,
• 28:32
  Speaker 1: which is what the name originally was given in General
• 28:35
  Speaker 1: relativity exactly. Early on, it was sort of the only
• 28:37
  Speaker 1: candidate to explain these kind of things, and that's one
• 28:40
  Speaker 1: reason why people started believing they exist. But recently there's
• 28:43
  Speaker 1: been sort of a flourishing of other ideas, other possibilities
• 28:46
  Speaker 1: that might explain the same observations, Other things that would
• 28:50
  Speaker 1: look just like these black holes but would not be
• 28:53
  Speaker 1: black holes. We talked about a few of them on
• 28:55
  Speaker 1: the podcast, things like dark stars. These are stars that
• 28:58
  Speaker 1: are collapsing due to gravity, but they're collapsing super duper
• 29:02
  Speaker 1: slowly because the gravity slows down time, so it's not
• 29:06
  Speaker 1: actually a singularity. It's just sort of like a collapsing
• 29:09
  Speaker 1: star frozen in time, which eventually will bounce back and
• 29:12
  Speaker 1: maybe turn into like a white hole. Or we've talked
• 29:14
  Speaker 1: about fuzzballs which are these weird phenomena from string theory
• 29:18
  Speaker 1: and all sorts of other various ideas, And the thing
• 29:21
  Speaker 1: that all these ideas have in common is that they
• 29:23
  Speaker 1: are quantum mechanical. One of the big problems with the
• 29:26
  Speaker 1: idea of a black hole from general relativity is the
• 29:29
  Speaker 1: singularity is the idea of having all this mass in
• 29:32
  Speaker 1: a tiny little dot that breaks quantum mechanics. Quantum mechanics
• 29:36
  Speaker 1: says you can't do that. It violates the uncertainty principle
• 29:38
  Speaker 1: and all sorts of basic principles of quantum mechanics. And
• 29:41
  Speaker 1: general relativity is not compatible with quantum mechanics, which is
• 29:45
  Speaker 1: one reason why See inside a black hole would be
• 29:47
  Speaker 1: so awesome, because because they see finally a battle between
• 29:50
  Speaker 1: general relativity and quantum mechanics and see who won. So
• 29:53
  Speaker 1: we think almost certainly general relativity is wrong and needs
• 29:56
  Speaker 1: to be modified by some theory of quantum gravity that
• 29:59
  Speaker 1: tells us what else is going on inside a black hole.
• 30:02
  Speaker 1: Maybe it's basically like a general relativity black hole, but
• 30:05
  Speaker 1: with a quantum blob of a singularity instead of an
• 30:07
  Speaker 1: actual dot. Maybe it's something totally different, like a fuzzball
• 30:10
  Speaker 1: or a dark star or something even weirder. Yeah, it
• 30:14
  Speaker 1: could be some kind of strange crossover event in their
• 30:17
  Speaker 1: like Captain America versus Batman exactly. And it's also important
• 30:20
  Speaker 1: to understand that the black holes that we've sort of
• 30:23
  Speaker 1: figured out how to calculate, these predictions we've made for
• 30:26
  Speaker 1: like you should see a black hole under these conditions,
• 30:29
  Speaker 1: those only really describe very simplified situations. Nobody actually has
• 30:34
  Speaker 1: been able to calculate a black hole like the ones
• 30:37
  Speaker 1: that we see out there, that the ones we suspect
• 30:39
  Speaker 1: exist in our universe. The kind of black holes we
• 30:42
  Speaker 1: can calculate are the ones where you have like a
• 30:44
  Speaker 1: dot of mass and otherwise empty universe. We know how
• 30:47
  Speaker 1: to do that calculation in Einstein's theory. The Einstein's theory
• 30:51
  Speaker 1: is very very messy, it's very complicated. It's almost impossible
• 30:54
  Speaker 1: to do anything realistic like in Einstein's theory. You can't
• 30:57
  Speaker 1: even do two dots of mass. We can't even of
• 31:00
  Speaker 1: the Earth going around the Sun. In Einstein's theory, even
• 31:03
  Speaker 1: basic stuff like that is too hard. And so, for example,
• 31:06
  Speaker 1: what we haven't done in Einstein's theory is figure out
• 31:09
  Speaker 1: how a black hole can survive in an expanding universe
• 31:13
  Speaker 1: like we always do our calculations in a flat universe
• 31:16
  Speaker 1: where space isn't expanding, so nobody even really knows, like
• 31:19
  Speaker 1: what happens to a black hole when the universe is expanding,
• 31:22
  Speaker 1: especially if that black hole is spinning. So it's not
• 31:26
  Speaker 1: like we, even in general relativity, have a great description
• 31:29
  Speaker 1: of what we've seen out there in the universe. You
• 31:31
  Speaker 1: mean at least the general relativity version of them, right,
• 31:34
  Speaker 1: But there could be other versions of a black hole,
• 31:36
  Speaker 1: or like a dark hole or a black divid maybe
• 31:41
  Speaker 1: that do I explain what's out there. We're not quite
• 31:43
  Speaker 1: sure what that is right exactly, And we also don't
• 31:46
  Speaker 1: know how they get so big sometimes exactly. That's one
• 31:48
  Speaker 1: of the other really deep mysteries about black holes, especially
• 31:51
  Speaker 1: the kind of black holes talked about in this paper.
• 31:53
  Speaker 1: These are the black holes at the centers of galaxies.
• 31:56
  Speaker 1: You can have a black hole just from a star
• 31:58
  Speaker 1: at the end of its life, it goes to Brenova
• 32:00
  Speaker 1: and collapses and you get a black hole. It's like
• 32:02
  Speaker 1: five or ten times the mass of our sun. That's
• 32:04
  Speaker 1: cool we see in those when we think we understand them.
• 32:06
  Speaker 1: But also there tend to be black holes at the
• 32:09
  Speaker 1: hearts of galaxies, Like at the center of our galaxy
• 32:11
  Speaker 1: there's a very big black hole with lots and lots
• 32:14
  Speaker 1: of mass, And at the center of many galaxies there
• 32:16
  Speaker 1: are black holes with millions or billions of times the
• 32:19
  Speaker 1: mass of our Sun. And we see these even very
• 32:22
  Speaker 1: far back in the early universe. If you look at
• 32:25
  Speaker 1: light that's been traveling for a very very long time
• 32:27
  Speaker 1: from very distant galaxies, you can see galaxies in the
• 32:30
  Speaker 1: first billion years of the universe that already have black
• 32:33
  Speaker 1: holes at their centers that are like a billion times
• 32:35
  Speaker 1: the mass of the Sun. And this is a big mystery.
• 32:38
  Speaker 1: Nobody understands how those black holes got so big so fast. Well,
• 32:42
  Speaker 1: it's kind of an amazing thing that we can tell
• 32:44
  Speaker 1: that there are black holes in these galaxies so far away. Yeah,
• 32:48
  Speaker 1: that's exactly right. It's fascinating, and we can tell them
• 32:50
  Speaker 1: often because they are quasars. Quasars are black holes that
• 32:54
  Speaker 1: have very strong magnetic fields that are spinning really really fast,
• 32:58
  Speaker 1: and so they emit these jets of light that are
• 33:00
  Speaker 1: super duper bright, so we can see them from very
• 33:03
  Speaker 1: very far away, so they're not always like super direct
• 33:06
  Speaker 1: observations of the black holes it's not like we've imaged
• 33:08
  Speaker 1: them the way we've imaged a couple of black holes
• 33:10
  Speaker 1: using the event horizon telescope. Again, black holes are almost
• 33:13
  Speaker 1: always indirect, but we're pretty confident that there's something very
• 33:17
  Speaker 1: dark and very massive and very dense at the hearts
• 33:20
  Speaker 1: of these galaxies. And we don't understand how you make
• 33:22
  Speaker 1: a gravitational object whatever it is, that massive, Like there
• 33:26
  Speaker 1: just isn't enough time for it to eat enough gas
• 33:28
  Speaker 1: and dust and stars to get that big that fast.
• 33:32
  Speaker 1: So there's all sorts of theories about how those black
• 33:34
  Speaker 1: holes might have gotten so big so fast it was
• 33:38
  Speaker 1: super mass. Now we have two big mysteries, two big
• 33:41
  Speaker 1: things out there in space. One is the expansion of
• 33:44
  Speaker 1: the universe. It's getting bigger and bigger, faster and faster.
• 33:47
  Speaker 1: We don't know that that's dark energy. And then there's
• 33:50
  Speaker 1: black holes, which we know some about but we're not
• 33:53
  Speaker 1: quite sure on the details or what's actually going on
• 33:55
  Speaker 1: inside of them. And now this new paper says and
• 33:58
  Speaker 1: maybe these two things are related, like maybe black holes
• 34:02
  Speaker 1: are the reason the universe is expanding. So what does
• 34:04
  Speaker 1: this paper actually say. Yeah, it's super fun and fascinating. Actually,
• 34:08
  Speaker 1: the couple of papers. The first paper makes a really
• 34:11
  Speaker 1: interesting just sort of observation about the masses of black holes. Wait,
• 34:15
  Speaker 1: it's several papers. Yeah, they wrote a couple of papers.
• 34:18
  Speaker 1: The first paper is like details of about the black
• 34:21
  Speaker 1: hole masses, and the second paper is this crazy theoretical
• 34:24
  Speaker 1: interpretation about it. Like they dropped the movie and the
• 34:27
  Speaker 1: sequel of the exactly. Yeah, two seasons of your favorite
• 34:31
  Speaker 1: show all the same time. The Netflix model of physics
• 34:34
  Speaker 1: or the event I guess, the Avengers endgame model. There
• 34:37
  Speaker 1: you go, film both movies at the same time. We
• 34:39
  Speaker 1: often do this. We work on several papers all at
• 34:41
  Speaker 1: once and then publish them all at the same time
• 34:44
  Speaker 1: because they're all sort of connected to each other. Or
• 34:46
  Speaker 1: you want to be the first person to write an
• 34:47
  Speaker 1: interpretation of your crazy new observation, so you write your
• 34:51
  Speaker 1: interpretation paper at the same time as you write your
• 34:53
  Speaker 1: observation paper, and you publish them separately. All right, So
• 34:56
  Speaker 1: this paper is talking about the masses of these black holes.
• 34:59
  Speaker 1: They went out and they measured the masses of a
• 35:01
  Speaker 1: bunch of black holes. Over time, they looked at closer
• 35:04
  Speaker 1: by galaxies that are newer, and they look deep into
• 35:07
  Speaker 1: the ancient past at very old galaxies, and they were
• 35:10
  Speaker 1: interested in how fast black holes are getting bigger. Like,
• 35:14
  Speaker 1: you have a galaxy and it's spinning, it's got a
• 35:16
  Speaker 1: black hole at its center. Black hole is going to
• 35:18
  Speaker 1: be eating gas and dust and stars, and the galaxies
• 35:21
  Speaker 1: also grow. Galaxies grow by gobling up gas from the
• 35:24
  Speaker 1: intergalactic medium and also by merging with each other. So
• 35:28
  Speaker 1: essentially what they did is they compared these two things.
• 35:30
  Speaker 1: They said, well, how fast are black holes growing and
• 35:33
  Speaker 1: how fast are galaxies growing? And what they noticed is
• 35:37
  Speaker 1: that the galaxies are not growing as fast as the
• 35:40
  Speaker 1: black holes are growing. So one question is like, well,
• 35:42
  Speaker 1: how did black holes get big in the early universe.
• 35:44
  Speaker 1: The other question is how do they keep getting bigger
• 35:48
  Speaker 1: all the time. So this is a really interesting result
• 35:50
  Speaker 1: because they're showing that black holes are growing unexplainedly quickly.
• 35:55
  Speaker 1: I see. Okay, So this first paper that's sort of
• 35:57
  Speaker 1: like a survey, right, Like they just looked at into
• 35:59
  Speaker 1: space and they looked at the younger galaxies and older
• 36:02
  Speaker 1: galaxies that have black holes in them, super massive black holes,
• 36:06
  Speaker 1: and they compared the young galaxies with the older galaxies,
• 36:10
  Speaker 1: and they said, between the two, in general, our galaxies
• 36:13
  Speaker 1: getting bigger and at what rate? And for those black holes?
• 36:17
  Speaker 1: Are those black holes getting bigger and at what rate?
• 36:19
  Speaker 1: And you're saying that the first paper just says black
• 36:21
  Speaker 1: holes seem to be getting bigger faster than galaxies are
• 36:23
  Speaker 1: getting bigger. Yeah, black holes are getting bigger, like eat
• 36:27
  Speaker 1: to twenty times faster than the galaxies they are in.
• 36:30
  Speaker 1: They are growing much more quickly than the rest of
• 36:33
  Speaker 1: their neighborhoods. But wouldn't that be explained by the idea
• 36:36
  Speaker 1: that the black holes are basically eating the galaxies because
• 36:39
  Speaker 1: like galaxies don't have a lot of things around them,
• 36:42
  Speaker 1: so they can't really grow that fast. But black holes
• 36:45
  Speaker 1: have a galaxy around them, and so maybe it could
• 36:47
  Speaker 1: just be that the black holes are eating up their
• 36:49
  Speaker 1: own galaxies and getting bigger. That way, we actually do
• 36:51
  Speaker 1: expect galaxies to grow. Remember that something like forty to
• 36:54
  Speaker 1: fifty percent of all the protons in the universe are
• 36:57
  Speaker 1: not eating galaxies yet they're between galaxies. There are these
• 37:01
  Speaker 1: filaments of gas between the galaxies that are still flowing
• 37:04
  Speaker 1: into the galaxies. Right now, every galaxy sits at the
• 37:07
  Speaker 1: bottom of a gravitational well created by its dark matter,
• 37:11
  Speaker 1: and there are these like rivers of gas flowing into
• 37:13
  Speaker 1: galaxies making them bigger, and then also galaxies merge, and
• 37:16
  Speaker 1: so galaxies we do expect them to grow, and you're right,
• 37:19
  Speaker 1: black holes we also expect them to grow. And you
• 37:22
  Speaker 1: can do studies of these things, and you can predict
• 37:24
  Speaker 1: how fast galaxies and black holes should grow, and it
• 37:26
  Speaker 1: should be about the same rate. You know, there's some
• 37:29
  Speaker 1: limit to how fast a black holes should be able
• 37:32
  Speaker 1: to grow because as it gets more powerful, it's acretion
• 37:34
  Speaker 1: disk gets very intense the stuff that's swirling around it,
• 37:38
  Speaker 1: and it is very hot and agitated and hasn't yet
• 37:40
  Speaker 1: fallen back into the black hole, and it generates a
• 37:42
  Speaker 1: lot of radiation which actually pushes away gas. So black
• 37:45
  Speaker 1: holes can't just grow like infinitely quickly, and galaxies should
• 37:49
  Speaker 1: be able to grow about the same rate. But what
• 37:51
  Speaker 1: we see is a big discrepancy that we don't understand.
• 37:54
  Speaker 1: So black holes are growing much faster than their galaxies,
• 37:58
  Speaker 1: which is not what our models predict. M Okay, that's
• 38:01
  Speaker 1: a mystery. That's a weird thing. So that's the first
• 38:03
  Speaker 1: paper and the second paper says, well, you know, black
• 38:07
  Speaker 1: holes are growing faster than we think, but it's actually
• 38:10
  Speaker 1: connected to something else. They notice that black holes are
• 38:14
  Speaker 1: growing at the same rate as the universe itself. That
• 38:17
  Speaker 1: the expansion of the universe we talked about, this unexplained
• 38:20
  Speaker 1: accelerated expansion matches very nicely the rate at which black
• 38:25
  Speaker 1: holes are gaining mass. So these two unexplained things seem
• 38:29
  Speaker 1: to be happening about the same pace. Like let's say
• 38:34
  Speaker 1: the universe is expanding how fast, like a thousand percent
• 38:38
  Speaker 1: per year or something like that. The expansion rand of
• 38:40
  Speaker 1: universe is a little bit more tricky to measure. It's
• 38:41
  Speaker 1: in terms of like kilometers per parsee per second, so
• 38:44
  Speaker 1: it's a little bit complicated. But you know, in a
• 38:47
  Speaker 1: cartoon version, it's like if the volume of the universe
• 38:49
  Speaker 1: doubles soared the mass of these black holes. So as
• 38:52
  Speaker 1: the universe gets bigger, black holes get bigger at the
• 38:55
  Speaker 1: same rate, which could just be a huge coincidence perhaps,
• 39:00
  Speaker 1: But these maybe these authors are saying that it's not
• 39:02
  Speaker 1: a coincidence exactly. These authors are saying it's not a coincidence,
• 39:06
  Speaker 1: and they have a theory which predicts this, which explains
• 39:10
  Speaker 1: the connection between the black holes mask getting bigger unexplainedly,
• 39:14
  Speaker 1: and the universe getting bigger unexplainedly. They want to explain
• 39:18
  Speaker 1: both of these things at the same time. All right, well,
• 39:21
  Speaker 1: I'm hooked. I want to know what this theory is,
• 39:23
  Speaker 1: and so let's dig into it. And also let's see
• 39:25
  Speaker 1: what our critic Daniel has to say about this theory.
• 39:29
  Speaker 1: But first, let's take another quick break or I we're
• 39:44
  Speaker 1: talking about the expansion of the universe, and a new
• 39:47
  Speaker 1: paper or a new set of papers it says that
• 39:49
  Speaker 1: maybe black holes are the ones that are somehow connected
• 39:52
  Speaker 1: to this expansion of the universe. So we talked about
• 39:55
  Speaker 1: how the universe seems to be expanding at a high rate.
• 39:59
  Speaker 1: That also seems to Madge how fast black holes out
• 40:02
  Speaker 1: there in the middle of galaxies are expanding, which could
• 40:04
  Speaker 1: be a coincidence. But these authors are saying that it's not,
• 40:07
  Speaker 1: and they have a theory that links the two of them. So, Daniel,
• 40:10
  Speaker 1: what's the theory. So the theory is pretty crazy but
• 40:14
  Speaker 1: also a lot of fun. The idea is that black
• 40:17
  Speaker 1: holes are not black holes as we imagined in general relativity.
• 40:20
  Speaker 1: They're not point masses at the centers of these event horizons. Instead,
• 40:25
  Speaker 1: there's something very very different that inside the event horizon
• 40:29
  Speaker 1: is not a point mass, but instead it's a ball
• 40:32
  Speaker 1: of vacuum energy. So what does vacuum energy? What does
• 40:36
  Speaker 1: that mean? Remember, vacuum energy is the thing we thought
• 40:40
  Speaker 1: might explain the expansion of the universe. We know in
• 40:43
  Speaker 1: general relativity, if the universe if empty space, what we
• 40:47
  Speaker 1: call the vacuum space, particles in it that has some
• 40:50
  Speaker 1: kind of energy, and that energy can drive the expansion
• 40:53
  Speaker 1: of the universe. In this theory, instead of having that
• 40:55
  Speaker 1: energy everywhere in the universe, you have like localized blobs
• 40:59
  Speaker 1: of that energy. It can form black holes that regions
• 41:03
  Speaker 1: of very very high vacuum energy and form something that
• 41:06
  Speaker 1: looks like a black hole. What okay, okay, let's maybe
• 41:10
  Speaker 1: take a step back here. Are they saying that when
• 41:13
  Speaker 1: you make a black hole, you're creating a bubble of
• 41:16
  Speaker 1: vacuum energy, or are you saying that when you have
• 41:19
  Speaker 1: a lot of vacuum energy that is what you call
• 41:21
  Speaker 1: a black hole. It's the second we're saying that the
• 41:24
  Speaker 1: things we're calling black holes are actually bubbles of vacuum energy.
• 41:28
  Speaker 1: They're not compressed masses. Here, we're talking about the things
• 41:31
  Speaker 1: that the centers of galaxies, stellar black holes from collapsed stars,
• 41:34
  Speaker 1: probably black holes that's not what these guys are talking about.
• 41:37
  Speaker 1: They're talking about the huge blobs of the centers of galaxies.
• 41:40
  Speaker 1: They're suggesting they're not black holes like we imagined. Instead,
• 41:43
  Speaker 1: that are these weird blobs of vacuum energy that somehow
• 41:47
  Speaker 1: mysteriously form, or that are that started somehow, or that
• 41:50
  Speaker 1: the universe started with. What are they saying, are these bubbles?
• 41:53
  Speaker 1: How can they have the gravity of black holes if
• 41:56
  Speaker 1: they have negative energy? So they don't explain what this
• 42:00
  Speaker 1: vacuum energy is or where it comes from. That's just
• 42:04
  Speaker 1: sort of left a big question mark. But there is
• 42:06
  Speaker 1: a history of people developing these kinds of ideas. I mean,
• 42:09
  Speaker 1: go back to what we were talking about earlier, people
• 42:11
  Speaker 1: trying to understand how you could have a spinning black
• 42:15
  Speaker 1: hole in an expanding universe. Nobody's solved those equations in
• 42:18
  Speaker 1: Einstein's theory. Nobody really knows if it's even possible in
• 42:22
  Speaker 1: Einstein's theory. So that leads people to explore other kind
• 42:25
  Speaker 1: of things, like instead of having a singularity the heart
• 42:28
  Speaker 1: of it, what if you put like a little expanding
• 42:30
  Speaker 1: universe inside the black hole, right, it might help you
• 42:34
  Speaker 1: match the expanding universe outside the black hole. So they
• 42:37
  Speaker 1: put this sort of like expanding vacuum energy inside the
• 42:40
  Speaker 1: black hole, and what they see is an incredible distortion
• 42:43
  Speaker 1: of space. There's no singularity, there's no event horizon, but
• 42:48
  Speaker 1: there is an intense curvature of space, which would look
• 42:51
  Speaker 1: a lot like a black hole, in the same way
• 42:53
  Speaker 1: that like a fuzzball doesn't actually have an event horizon,
• 42:56
  Speaker 1: but it's still really curves space, and so it looks
• 42:59
  Speaker 1: a lot like a black hole, or the way a
• 43:01
  Speaker 1: dark star is not technically an event horizon because eventually
• 43:04
  Speaker 1: everything comes out of it. These things don't have event horizons.
• 43:08
  Speaker 1: They were invented in the sixties original by some Souviet physicists,
• 43:11
  Speaker 1: and people have been playing around with them. They're just
• 43:12
  Speaker 1: like another weird prediction of something that would look black
• 43:15
  Speaker 1: hole em but you would still get sucked into it
• 43:20
  Speaker 1: because I thought a vacuum energy, you know, had like
• 43:22
  Speaker 1: negative gravity or something like that. That's a cosmological connection
• 43:26
  Speaker 1: we'll get to in a minute. They think this vacuum
• 43:27
  Speaker 1: energy might be driving the expansion of the universe globally
• 43:31
  Speaker 1: but locally. Weirdly, it also looks like a black hole,
• 43:35
  Speaker 1: like if you're near by it then it bends space
• 43:38
  Speaker 1: intensely because instead of having vacuum energy everywhere, you have
• 43:42
  Speaker 1: it localized. It's only this one spot at the heart
• 43:45
  Speaker 1: of the galaxy, So that discrepancy having it there but
• 43:48
  Speaker 1: not over here creates curvature in the region between it
• 43:51
  Speaker 1: and that looks a lot like a black hole. It
• 43:53
  Speaker 1: looks like a black hole. But wouldn't it be like
• 43:56
  Speaker 1: reverse gravity, Like wouldn't it push things away like in
• 43:59
  Speaker 1: the pulling ball analogy in the rubber sheet. Wouldn't something
• 44:03
  Speaker 1: like this be like lifting up the rubber sheet, like
• 44:06
  Speaker 1: pinching it and pulling it up? Or am I getting
• 44:08
  Speaker 1: vacuum energy confused with negative energy? This is not negative energy, right?
• 44:12
  Speaker 1: Vacuum energy is just potential energy, not negative energy. And
• 44:16
  Speaker 1: Einstein's equations are not very intuitive, right, Like, it's not
• 44:19
  Speaker 1: very intuitive to understand why in some cases potential energy
• 44:22
  Speaker 1: causes expansion of space. Here, this vacuum energy seems to
• 44:26
  Speaker 1: be doing two things. It creates this almost kind of
• 44:29
  Speaker 1: like event horizon locally and also drives the expansion of
• 44:33
  Speaker 1: the universe globally. Whether this makes any sense at all
• 44:36
  Speaker 1: is a topic of intense debate among cosmologists. I talked
• 44:39
  Speaker 1: to a bunch of them over this last week. Half
• 44:41
  Speaker 1: of them were like, this is nonsense. The other half
• 44:44
  Speaker 1: was like, well, maybe under certain conditions that might happen.
• 44:47
  Speaker 1: But this is definitely a very, very fringe theory that
• 44:50
  Speaker 1: a lot of cosmologists don't accept. Even just this part
• 44:54
  Speaker 1: of it, This idea of a Gravis star something with
• 44:57
  Speaker 1: vacuum energy inside it, which looks like a black hole
• 45:00
  Speaker 1: from the outside. A lot of people don't believe that's
• 45:02
  Speaker 1: even possible. Well, what's their excuse for it, Like, how
• 45:06
  Speaker 1: do they explain it? Why is there so much vacuum
• 45:08
  Speaker 1: energy concentrated in one spot? What keeps it together? They
• 45:11
  Speaker 1: don't have an explanation in this paper. What they do
• 45:13
  Speaker 1: is they say, look, there's an apparent connection between the
• 45:15
  Speaker 1: mass of the black holes and the expansion of the universe.
• 45:18
  Speaker 1: And if you accept this theory that there are vacuum
• 45:22
  Speaker 1: energy interior or objects at the hearts of these galaxies
• 45:25
  Speaker 1: that would explain it, it doesn't argue for that theory.
• 45:28
  Speaker 1: It doesn't justify that theory, doesn't explain where this vacuum
• 45:31
  Speaker 1: energy comes from or what it is at all. It
• 45:33
  Speaker 1: just says that there is a theory that allows you
• 45:36
  Speaker 1: to connect these two observations. It feels kind of like
• 45:38
  Speaker 1: a made up theory, a little bit like it feels
• 45:40
  Speaker 1: like the issues came up with a theory just to
• 45:43
  Speaker 1: say that they have a theory. It's a little bit
• 45:45
  Speaker 1: at hoc, right, It's not something that's been thoroughly worked out. Again, remember,
• 45:48
  Speaker 1: nobody knows how to solve Einstein's equations under all these
• 45:51
  Speaker 1: weird conditions expanding universes, spinning stuff, vacuum interiors, or singularities.
• 45:56
  Speaker 1: Nobody knows what the solutions are like, so nobody can
• 46:00
  Speaker 1: even really say if this is consistent or inconsistent with
• 46:03
  Speaker 1: general relativity. Some of the cosmologists I talk to you said,
• 46:06
  Speaker 1: there's no way this is consistent with gr Other people thought, hey,
• 46:09
  Speaker 1: maybe it might be. There are people working on these
• 46:12
  Speaker 1: kinds of solutions. But the really interesting part of the
• 46:14
  Speaker 1: paper is that they argue that having this vacuum energy
• 46:18
  Speaker 1: inside the black holes somehow contributes to the expansion of
• 46:21
  Speaker 1: the universe as a whole. I mean, we're used to
• 46:24
  Speaker 1: thinking black holes like acting locally, they suck stuff in nearby.
• 46:28
  Speaker 1: This is suggesting that because they have vacuum energy in them,
• 46:31
  Speaker 1: instead of like dense mass. They're also contributing to the
• 46:34
  Speaker 1: cosmological equation of state, the thing that affects the entire
• 46:38
  Speaker 1: expansion or contraction of the universe. And that's even harder
• 46:42
  Speaker 1: for most cosmologists I talk to to swallow. Yeah, because
• 46:45
  Speaker 1: it's not like these black holes are everywhere and spread
• 46:48
  Speaker 1: evenly across the universe. They're just at the very center
• 46:51
  Speaker 1: of some galaxies, and those galaxies are pretty far apart
• 46:54
  Speaker 1: from each other. Right, If they are the source of
• 46:56
  Speaker 1: expansion in the universe, wouldn't you then see like hot
• 46:59
  Speaker 1: spots of exp in some places, and in places where
• 47:02
  Speaker 1: there are in delities or black holes, you would see
• 47:05
  Speaker 1: no expansion. Yeah, that's exactly right, and that would be
• 47:07
  Speaker 1: very very weird and also not explained in this paper.
• 47:10
  Speaker 1: They don't even really talk about this aspect of it,
• 47:13
  Speaker 1: and it would be something very very strange in physics.
• 47:16
  Speaker 1: We have in physics this sort of like hierarchy of scales,
• 47:19
  Speaker 1: where really tiny stuff doesn't usually affect really really big stuff,
• 47:23
  Speaker 1: like things that happen inside the Sun don't affect the
• 47:26
  Speaker 1: galaxy as a whole, or things that you do don't
• 47:28
  Speaker 1: usually affect the motion of the entire Earth. Where the
• 47:32
  Speaker 1: sort of hierarchy of scales, really really high energy stuff
• 47:35
  Speaker 1: at very very small distances doesn't usually affect low energy
• 47:39
  Speaker 1: stuff over larger distances, and this would break that. This
• 47:43
  Speaker 1: would say the things that are happening like inside black
• 47:45
  Speaker 1: holes can affect the universe as a whole. That's very
• 47:49
  Speaker 1: very weird. It's weird, not just because black holes are
• 47:52
  Speaker 1: weird and dark energy is weird. It would require like
• 47:55
  Speaker 1: a very different sort of paradigm of physics. It would
• 47:57
  Speaker 1: tell something very very new is going going on, something
• 48:00
  Speaker 1: hard to swallow. Yeah, like, yeah, these sources of vacuum
• 48:04
  Speaker 1: energy and somehow their effect is evenly spread out to
• 48:07
  Speaker 1: the universe somehow. That's kind of what you're saying, right,
• 48:10
  Speaker 1: That would be weird. That would be very strange. And
• 48:12
  Speaker 1: that doesn't mean it's not happening. We should be ready
• 48:15
  Speaker 1: for strange stuff. History of physics is filled with times
• 48:18
  Speaker 1: when people are like, well, the only way to explain
• 48:21
  Speaker 1: this would be this totally crazy idea that can't possibly
• 48:24
  Speaker 1: be true, And then it turns out it is true.
• 48:26
  Speaker 1: It just it requires us to accept something new. This
• 48:28
  Speaker 1: could be one of those moments, right, or maybe not.
• 48:31
  Speaker 1: So It's not always easy to tell, but there's a
• 48:34
  Speaker 1: lot of skepticism. One reason is that this is like
• 48:37
  Speaker 1: an explanation for what's happening. It's not at all a
• 48:41
  Speaker 1: conclusive explanation. It's not the unique explanation. It might be
• 48:45
  Speaker 1: that you could explain black holes growing at the same
• 48:48
  Speaker 1: rate of the universe in some other way. Instead of
• 48:50
  Speaker 1: black holes driving the expansion of the universe, maybe there
• 48:53
  Speaker 1: is something else that's driving both. Right, So it feels
• 48:57
  Speaker 1: sort of like this describes it, but it doesn't clinch
• 49:00
  Speaker 1: it necessarily. We're not sure that this is what's happening
• 49:03
  Speaker 1: just because it describes it. Science has to be predictive,
• 49:07
  Speaker 1: not just descriptive. It could just be a coincidence, is
• 49:10
  Speaker 1: what you're saying. It could be a coincidence, or could
• 49:12
  Speaker 1: just be that we have the causality backwards. Instead of
• 49:15
  Speaker 1: black holes driving the expansion of the universe, something else
• 49:17
  Speaker 1: could be driving both of them, so they could be connected.
• 49:20
  Speaker 1: It just might not be this theory of vacuum interior
• 49:23
  Speaker 1: black holes driving somehow magically the expansion of the universe. Well,
• 49:27
  Speaker 1: that would be a juicy headline too. Couldn't the expansion
• 49:31
  Speaker 1: of the universe be making black holes bigger. I mean
• 49:33
  Speaker 1: that's the idea, right, Like, maybe the universe is expanding
• 49:36
  Speaker 1: for some reason, for because of dark energy, and somehow
• 49:39
  Speaker 1: that a fact causes black holes to get bigger too. Yeah, exactly,
• 49:42
  Speaker 1: And if you understood where this vacuum energy came from,
• 49:45
  Speaker 1: maybe that would be the source of it. And this paper, again,
• 49:48
  Speaker 1: it doesn't address that. Either doesn't say where this vacum
• 49:51
  Speaker 1: energy is coming from or what it's made out of.
• 49:52
  Speaker 1: Is it made out of quantum fields like we suspect,
• 49:55
  Speaker 1: or is it something totally different. We just don't know.
• 49:58
  Speaker 1: But this paper got peer reviewed, and if you had
• 50:00
  Speaker 1: been one of the peer reviewers, what would you have
• 50:02
  Speaker 1: set If I had been one of the peer reviewers,
• 50:04
  Speaker 1: I would have asked for a lot more details about
• 50:06
  Speaker 1: this theory and some comments about these obvious questions, you know,
• 50:10
  Speaker 1: like how is it possible for localized objects to contribute
• 50:13
  Speaker 1: globally to the expansion of the universe, and also how
• 50:16
  Speaker 1: is it possible for black holes whose mass is a
• 50:20
  Speaker 1: tiny fraction of the mass of the universe? Right, black
• 50:23
  Speaker 1: holes are a little fraction of the five percent of
• 50:25
  Speaker 1: the universe that's our kind of stuff. Dark energy is
• 50:29
  Speaker 1: seventy percent how is it possible for this tiny mass
• 50:32
  Speaker 1: fraction to drive this huge energy in the universe. So
• 50:35
  Speaker 1: I want to ask those questions, and I imagine that
• 50:38
  Speaker 1: the authors of this paper are getting those questions from
• 50:40
  Speaker 1: their colleagues, and I'm looking forward to hearing some answers
• 50:43
  Speaker 1: and some follow up papers. Well, it sort of sounds like,
• 50:45
  Speaker 1: you know, they discovered something that is significant and is
• 50:48
  Speaker 1: interesting and it is noteworthy. Right, they discovered that black
• 50:52
  Speaker 1: holes are increasing at a rate that's higher than the
• 50:55
  Speaker 1: galaxies around them, and they're also increasing at a rate
• 50:58
  Speaker 1: that seems to match the expansion of the universe. Like,
• 51:00
  Speaker 1: that's an interesting result. The right that it hadn't been
• 51:02
  Speaker 1: published before that is definitely a very interesting result. So
• 51:05
  Speaker 1: that's probably, you know, publish worthy. It's just that the
• 51:08
  Speaker 1: ideas are putting forth to maybe explain this are a
• 51:11
  Speaker 1: little bit on the fringe side, and that's probably also
• 51:13
  Speaker 1: why they put it out in two different papers. The
• 51:15
  Speaker 1: first one, he's here the black holes we found. The
• 51:18
  Speaker 1: second one is here's our crazy idea to explain it.
• 51:20
  Speaker 1: And so the second one is definitely a bit more speculative.
• 51:23
  Speaker 1: There are also questions being raised about the first paper,
• 51:25
  Speaker 1: you know, people are looking at this paper and saying, well,
• 51:28
  Speaker 1: you've looked at a bunch of black holes snapshots in time.
• 51:31
  Speaker 1: You never watched an individual black hole grow at the
• 51:35
  Speaker 1: rate of the universe. We can't possibly do that. You
• 51:37
  Speaker 1: have to observe it for billions of years. Instead, you
• 51:39
  Speaker 1: look at different black holes through history, and you try
• 51:42
  Speaker 1: to tell a story about how, in general black holes
• 51:44
  Speaker 1: are growing. There are some assumptions there that you're making, right,
• 51:47
  Speaker 1: that black holes in different regions of the universe who
• 51:49
  Speaker 1: are growing at the same rates, etc. And so people
• 51:52
  Speaker 1: are also asking questions about that paper. But I think
• 51:54
  Speaker 1: that one's probably pretty solid. It's really this connection between
• 51:57
  Speaker 1: black holes and the dark energies theoretical interpretation that's a
• 52:01
  Speaker 1: lot more speculative and a lot of fun also, right,
• 52:04
  Speaker 1: And I want to be too negative about it. I
• 52:06
  Speaker 1: love new ideas, I love breakthroughs, I love speculation. But
• 52:10
  Speaker 1: you know, we got to put it in context and
• 52:11
  Speaker 1: think about all the question marks that come with it. Right.
• 52:14
  Speaker 1: But that's kind of the norm in physics, right, Like,
• 52:16
  Speaker 1: if you have a wild idea, you're allowed to publish
• 52:19
  Speaker 1: a paper with a wild idea, right, Like, as long
• 52:23
  Speaker 1: it has some sort of basis in reality, or at
• 52:26
  Speaker 1: least some indication some hints that are based in reality,
• 52:29
  Speaker 1: which this one did. You're sort of allowed in physics, right,
• 52:31
  Speaker 1: the polish crazy ideas. Sure, And it's also totally reasonable
• 52:34
  Speaker 1: to start off with a half formed idea to say, look,
• 52:37
  Speaker 1: here's something crazy and fascinating. We don't have all the
• 52:40
  Speaker 1: details worked out, but maybe it's something in this direction.
• 52:42
  Speaker 1: And somebody else will read the paper and be like, huh,
• 52:44
  Speaker 1: here's an obvious hole that needs to be filled. I
• 52:47
  Speaker 1: wonder if And then I'll have an idea and they'll
• 52:49
  Speaker 1: explain it. And so it's totally fine to not have
• 52:52
  Speaker 1: solved everything in one paper, right, to say, maybe this
• 52:55
  Speaker 1: direction works, and here's some indications that it might be
• 52:58
  Speaker 1: a fruitful path. Let's keep going this way, and then
• 53:01
  Speaker 1: everybody jumps on it. I need to proves them wrong
• 53:03
  Speaker 1: or supports it. We'll see. Yeah, like the Higgs boson.
• 53:06
  Speaker 1: I mean, Peter Higgs got the Nobel Prijec because he
• 53:09
  Speaker 1: polished the crazy idea without a lot of paces in
• 53:12
  Speaker 1: an actual experiments. Right, He's like, hey, maybe there's a
• 53:15
  Speaker 1: field called the Higgs field and the Higgs boson, and
• 53:18
  Speaker 1: and that was an explanation, right, It was an explanation
• 53:21
  Speaker 1: and not the only explanation exactly. And one nice thing
• 53:24
  Speaker 1: about this paper is that they suggest some ways to
• 53:27
  Speaker 1: check these results. As a bunch of details that people
• 53:30
  Speaker 1: can do studying the causer of microwave background and how
• 53:32
  Speaker 1: stars are whizzing around, they make a bunch of predictions
• 53:35
  Speaker 1: if this theory is right, things we might be able
• 53:37
  Speaker 1: to test. And so there's a lot of really fun
• 53:39
  Speaker 1: work we can do in the next few years to
• 53:41
  Speaker 1: see if indeed black holes aren't driving the expansion of
• 53:44
  Speaker 1: the universe or not. Do you think I can get
• 53:46
  Speaker 1: my theory polish through peer review about Superman and Spider
• 53:50
  Speaker 1: Man causing the growth of black hole? I think you
• 53:54
  Speaker 1: have to choose very carefully the journal you're going to
• 53:56
  Speaker 1: send that to, Yeah, the Journal of or hit cham
• 54:01
  Speaker 1: on Twitter. There you go. Or I'll put it on
• 54:03
  Speaker 1: archive at archive dot org. There you go, Archive dot
• 54:07
  Speaker 1: org ya, And then I can be a polished physics theorist.
• 54:10
  Speaker 1: Join the club. All right, Well, lots to think about here,
• 54:13
  Speaker 1: I guess again. The main lesson is stay tuned. I mean,
• 54:16
  Speaker 1: people have crazy ideas about things, and they observe the
• 54:19
  Speaker 1: universe and they find interesting coincidences and that may or
• 54:22
  Speaker 1: may not be coincidences. And that's how science moves forward,
• 54:25
  Speaker 1: is noticing these weird things and putting out their potentially
• 54:29
  Speaker 1: crazy ideas that sometimes turn out to be true, and
• 54:31
  Speaker 1: we can't always tell them the moment, which paper is
• 54:34
  Speaker 1: going to be something that resonates through history and is
• 54:37
  Speaker 1: read by generations to come, and which is just going
• 54:39
  Speaker 1: to be another in an exciting press release that nobody
• 54:42
  Speaker 1: ever talked about Again. All right, well, we hope you
• 54:44
  Speaker 1: enjoyed that. Thanks for joining us, see you next time.
• 54:55
  Speaker 1: Thanks for listening, and remember that Daniel and Jorge explain
• 54:58
  Speaker 1: the Universe is a product shit of iHeartRadio. For more
• 55:02
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• 55:06
  Speaker 1: or wherever you listen to your favorite shows.