Speaker 1: Hey, Daniel, what's your favorite kind of Daniel and Horry
Speaker 1: explain the Universe podcast episode. Oh, I don't know, so
Speaker 1: hard to pick. I do love the Extreme Universe series though.
Speaker 1: Those are extremely fun. And then you know, I also
Speaker 1: really love the science fiction author ones because I get
Speaker 1: to talk to really clever writers. That is every fanboys dream.
Speaker 1: But I have to admit I think my absolute favorites
Speaker 1: are the listener questions episodes. Oh yeah, what well? I
Speaker 1: just like knowing that this is something a real listener
Speaker 1: wondered about. You like knowing it's not just some crazy
Speaker 1: detail of particle physics nobody else wants to hear about.
Speaker 1: What do you mean? Every detail of particle physics is fascinating?
Speaker 1: That is extremely true. I am Or I'm a cartoonists
Speaker 1: and the creator of PhD comics. Hi, I'm Daniel, I'm
Speaker 1: a particle physicist, and I'm the co author of the
Speaker 1: book We Have No Idea, a guide to all the
Speaker 1: crazy things we don't yet know about the Universe. Yeah,
Speaker 1: I'm a big fanboy of that book. Have you spoken
Speaker 1: to the authors yet? They're really hilarious. Oh man, I
Speaker 1: can't wait to get their signature, or maybe they can
Speaker 1: doodle something for me. Watch out though they can just
Speaker 1: go on and on about particle physics. Sometimes you know
Speaker 1: there's a danger in everything. But Welcome to our podcast
Speaker 1: Daniel and Jorga Explain the Universe, a production of our
Speaker 1: Heart Radio in which we talked about all the things
Speaker 1: we do know about the universe and all the things
Speaker 1: that we don't know about the universe. We embrace curiosity
Speaker 1: and mystery. We talked about everything from the size of
Speaker 1: the universe to the size of tiny particles. We unwrapped
Speaker 1: mysteries about the origins of universe, and we talked about
Speaker 1: whether or not protons will live forever. But mostly we
Speaker 1: are here to tickle your curiosity, to answer your questions,
Speaker 1: because science is just people asking questions and trying to
Speaker 1: figure out the answers, and that includes you. Yeah, and
Speaker 1: there is a lot to ask about in the universe.
Speaker 1: There's a lot we don't know and a lot that
Speaker 1: we are still learning. And sometimes what we're learning is
Speaker 1: what's on the minds of listeners like you. That's right.
Speaker 1: You may be shocked to discover that the questions you
Speaker 1: have in your minds are the same questions as scientists
Speaker 1: at the cutting edge are asking, and that's not just
Speaker 1: because you're super smart, but because some of these basic
Speaker 1: questions we've made very little progress on and we're still
Speaker 1: at the point of asking questions. So that's why on
Speaker 1: this podcast we encourage our listeners to send us their questions.
Speaker 1: To ask those questions. Yeah, and Daniel actually answer them.
Speaker 1: If you right into our Twitter account or if you
Speaker 1: email us at questions at Daniel and Jorge dot com.
Speaker 1: That's right. We answer every email and we answer every question.
Speaker 1: Sometimes people seem to be surprised when they actually get
Speaker 1: a response from me. They're like, whoa, You really do
Speaker 1: answer emails And they're like, aren't you supposed to be
Speaker 1: doing physics. News flash, I am supposed to be doing physics.
Speaker 1: But I love answering your emails. Seriously, every time I
Speaker 1: get an email from a listener, I think, what's this
Speaker 1: one going to ask? What crazy question that I've never
Speaker 1: thought of is going to be contained in this little
Speaker 1: digital package? And it's part of physics also to communicate
Speaker 1: what you guys know and what you don't know to
Speaker 1: the public. Right, So in a way, you're answering questions.
Speaker 1: Is doing physics. Hey, that's a good line. I'm gonna
Speaker 1: use that my next job performance review. Good luck. But
Speaker 1: I think you're absolutely right. And one of the things
Speaker 1: that I love about physics is that the questions are fascinating,
Speaker 1: but they're also big questions. There are questions that are
Speaker 1: relevant to everyone. They have deep philosophical implications. How is
Speaker 1: the universe created, how will it end? What is it
Speaker 1: all made of? You don't have to be an expert
Speaker 1: and how particles talk to each other in quantum field
Speaker 1: theory to know that if you have the answer to
Speaker 1: these questions, it could change the way you live your life.
Speaker 1: So physics is fast nating. But also because physics has
Speaker 1: deep implications. Yeah, and so we get a lot of
Speaker 1: questions from listeners and every once in a while we
Speaker 1: like to answer them on the podcast. To be on
Speaker 1: the program, we'll be tackling listener questions number thirteen, lucky
Speaker 1: number thirteen. Are you superstitious Daniel about the number thirteen? No?
Speaker 1: I actually kind of like the number thirteen. Is something
Speaker 1: cool about it? Really? It's a prime number. I like
Speaker 1: all prime numbers. Yeah, absolutely, prime numbers are awesome. This
Speaker 1: is just something about that number, Like seven thirteen thirteen
Speaker 1: is seven plus six I don't know. It's a cool number.
Speaker 1: What's your most favorite number? My most favorite number forty two?
Speaker 1: Of course, the answer to everything, life, the universe, and everything. Well.
Speaker 1: Today we have a couple of awesome questions from several readers.
Speaker 1: We have questions about water in the universe, about gamma
Speaker 1: rays from black holes, and also an awesome question about
Speaker 1: dark matter. It seems that people are curious about a
Speaker 1: lot of things, Daniel, People are curious about a lot
Speaker 1: of things. I get an amazing and hilarious breath of questions.
Speaker 1: We got a question last week about Santa Claus. What
Speaker 1: did they want to have? No, well or not Santa
Speaker 1: is also a physicist. No, but it was a physics
Speaker 1: related Santa Claus question. They thought, maybe the reason that
Speaker 1: Santa doesn't appear to age is because he has to
Speaker 1: travel so close to the speed of light that time
Speaker 1: dilation has slowed down his clock. Interesting, So I guess
Speaker 1: if you spend one day a year traveling at the
Speaker 1: speed of light that, well, that wouldn't help you very
Speaker 1: much with it, not very much, but you know it
Speaker 1: works in the right direction. And this was a question
Speaker 1: from an eight year old listener. So I'm thinking, Hey,
Speaker 1: that's pretty good. The physics of Santa relativity and the
Speaker 1: anti gravity of the reindeer, the infrared radiation of Rudolf's nose.
Speaker 1: What else? Maybe there's a wormhole or like a pocket
Speaker 1: universe in his bag? Oh man, I think that's your
Speaker 1: next I find I think that's our next book, The
Speaker 1: Physics of Christmas. There you go. It was sound really well. Now,
Speaker 1: so we get a lot of really awesome questions, some
Speaker 1: of which I can respond to right away, and some
Speaker 1: of which I think everybody might be interested in hearing
Speaker 1: about and also take a little bit more digging to answer.
Speaker 1: So those are the ones who usually feature on these
Speaker 1: Listener Questions episodes. All right, so let's jump in right away.
Speaker 1: The first question comes from Greg Preston and he has
Speaker 1: a question about water in the universe. Hi, Daniel and Jorge.
Speaker 1: I was listening to your podcast about the art cloud,
Speaker 1: which I'd like to refer to as a snowball's chance
Speaker 1: in order, and it got me thinking where all the
Speaker 1: water came from in the universe. I know water b
Speaker 1: n H two oh was made from two hydrogen molecules
Speaker 1: and one oxygen molecule, and I know there's a lot
Speaker 1: of hydrogen in the world, but I don't think there
Speaker 1: was really that much oxygen. And then how could there
Speaker 1: be that much water um not only on Earth but
Speaker 1: throughout the galaxy, or at least throughout the universe. So
Speaker 1: I was wondering if you had any idea where all
Speaker 1: the water came from. I appreciate it. Thanks and keep
Speaker 1: up the good work. Alright, awesome question, Thank you, Greg.
Speaker 1: The question is where does water come from in the universe. No,
Speaker 1: I imagine Daniel. It doesn't just come from the tap.
Speaker 1: There's no is there a universe tap. No, the universe
Speaker 1: buys bottled water, usually fancy. It likes sparkling water. Actually,
Speaker 1: you know, it's usually very bubbly. No, you can't just
Speaker 1: go out there into space and turn on the tap.
Speaker 1: But there is actually a lot of water out there
Speaker 1: in space. Really, how much is a lot? Like huge
Speaker 1: amounts of water, like vast quantities of water. I think
Speaker 1: people have gotten the idea that there's not much water
Speaker 1: in space because they know that NASA is out there
Speaker 1: on the hunt for water, looking for water so they
Speaker 1: can find places where it might be possible to have
Speaker 1: life be started. So people are familiar with this, like
Speaker 1: search for water, and that gives them the impression like
Speaker 1: water is rare because we haven't hound a lot of
Speaker 1: liquid water on surfaces, right, We haven't seen any other
Speaker 1: oceans out there, right, that's right. So we have liquid
Speaker 1: water in the surface of Earth, and there's no other
Speaker 1: body in the Solar System or galaxy that we're aware
Speaker 1: of that has liquid water on the surface. So that
Speaker 1: is indeed rare. Liquid water on the surface. You have
Speaker 1: to have enough water on the surface, you have to
Speaker 1: be close enough to the Sun so that it melts
Speaker 1: but doesn't vaporize. But that doesn't mean that the water
Speaker 1: molecule that the H two O itself is rare. There's
Speaker 1: a lot of it, I guess. But when you say
Speaker 1: in space or in the university, you mean like in
Speaker 1: our Solar system or just in general, like is the
Speaker 1: universe sprinkled with water vapor or is it mostly only
Speaker 1: where there are planets? Both? There's actually water basically everywhere.
Speaker 1: So our Solar system has vast quantities of water. First
Speaker 1: of all, a lot of the planets have big chunks
Speaker 1: of water and them like just look at Mars. Mars
Speaker 1: has ice caps on the poles. North Pole and South
Speaker 1: Pole have huge water reserves. Now that's not quid water
Speaker 1: on the surface like you would hope to see if
Speaker 1: you can find little green aliens swimming around. It's all ice,
Speaker 1: but that is water. Now, does the Mars Santa Claus
Speaker 1: also break the laws of physics? Or well, the Martian
Speaker 1: year is a little bit shorter than an Earth year,
Speaker 1: so you have to deliver presents more often, which I
Speaker 1: guess means spending more time at high speeds close to
Speaker 1: the speed of light. So yeah, Martian Santa Claus ages
Speaker 1: more slowly than Earth Santa Claus. Oh man, that's the
Speaker 1: sequel to the book. But it's not just Mars. There
Speaker 1: are other planets with a lot of water, right, that's right.
Speaker 1: If you wanted to find water in the Sol system,
Speaker 1: it would not be hard. Like look no further than
Speaker 1: the ice giants. Urinus and Neptune are called ice giants
Speaker 1: because they're mostly huge balls of ice, not just water.
Speaker 1: Ice is also like methane ice in there. But there
Speaker 1: are enormous quantities of frozen water in Urinus and Neptune.
Speaker 1: It's not hard to find water out there. And all
Speaker 1: the comets in the Orc Cloud, as the listener was suggesting,
Speaker 1: those are dirty snow balls. So this frozen water all
Speaker 1: over our solar system. So Uranus and Neptune are mostly water,
Speaker 1: like H two O water. They're like two thirds ice.
Speaker 1: Some fraction of that is methane and some fraction of
Speaker 1: it is H two O water. We're not exactly sure
Speaker 1: the proportions, but we know it's not zero percent water
Speaker 1: or one percent water. It's a significant fraction of it
Speaker 1: is frozen H two So it smelly water, it's not
Speaker 1: it's like methane. Yeah, it's not Fiji water. It's not
Speaker 1: water you want to drink immediately. But you know, if
Speaker 1: you're out there and you're looking for raw materials you
Speaker 1: need oxygen hydrogen either to drink or to make rocket fuel.
Speaker 1: There is plenty of water out there. You wouldn't need
Speaker 1: to like bring water with you from Earth. All right,
Speaker 1: So there's a lot of water in our solar system.
Speaker 1: But I guess maybe Greg's question is is like where
Speaker 1: did it all come from? Did it come from like
Speaker 1: a supernova? Does it does it regularly made by sons?
Speaker 1: Or did the universe just come with water? Yeah, it's
Speaker 1: a great question, and to begin to answer that you
Speaker 1: have to look a little bit further outside our solar
Speaker 1: system and ask like, is the water everywhere or is
Speaker 1: it unusual here? And we find water in lots of places.
Speaker 1: We find it in the interstellar medium. There's big gas clouds,
Speaker 1: you know, molecular clouds of basic raw materials that form
Speaker 1: solar systems, and a lot of them have frozen water
Speaker 1: in them, and so it's all over the place, and
Speaker 1: so you ask, well, where does it come from. Well,
Speaker 1: it's made of two ingredients, right, hydrogen and oxygen. Hydrogen
Speaker 1: is everywhere. It's literally the most plentiful thing in the universe.
Speaker 1: The number one thing that happened in the Big Bang
Speaker 1: was the creation of hydrogen. Is started out like nineties
Speaker 1: six percent hydrogen, so there's no shortage of hydrogen. The
Speaker 1: key thing is oxygen, as greg aye. And that's because
Speaker 1: hydrogen is the simplest element, right, Like it's just an
Speaker 1: electron and a proton. It's like the simplest thing you
Speaker 1: can make out of fundamental particles. That's right. You just
Speaker 1: need a proton and an electron and they come together
Speaker 1: and they make hydrogen. It's very simple, it's very happy.
Speaker 1: It's very easy to occur. To get heavier elements, you
Speaker 1: have to squeeze protons together to get an element like
Speaker 1: heally them or lithium or something heavier. You need multiple
Speaker 1: protons to come together to form a nucleus, and protons
Speaker 1: are positively charged, so they repel each other electromagnetically until
Speaker 1: you squeeze them close enough that the strong nuclear force
Speaker 1: sort of snaps them together. And that's fusion that can
Speaker 1: only happen in the heart of stars. Right, You need
Speaker 1: like a lot of a lot of it to start fusing, right,
Speaker 1: Like two hydrogen items won't just fuse out there in space.
Speaker 1: You need like a whole bunch of them squeezing together.
Speaker 1: That's right, You need a whole bunch of them. And
Speaker 1: so you start with a big cloud of stuff, and
Speaker 1: gravity is the force that pulls them all together, tugs
Speaker 1: on them, gradually squeezing them harder and harder, until eventually
Speaker 1: there's nowhere for those protons to go. They get squeezed
Speaker 1: together and they start to fuse. So you start with hydrogen.
Speaker 1: The first stars in the universe burned hydrogen and they
Speaker 1: made something which had two protons in it, which is helium.
Speaker 1: And then eventually, if you burn enough hydrogen, your stars
Speaker 1: have helium in them. So the second generation stars tended
Speaker 1: to burn hydrogen and helium and they were capable of
Speaker 1: then forming an even heavier element using helium together, for example,
Speaker 1: to make carbon. Yeah, so you fuse three helium adams
Speaker 1: and you get a carbon. Right. Yeah, there's a bunch
Speaker 1: of sort of complicated chains. Once you get just beyond
Speaker 1: hydrogen hydrogen fusion into helium, you have weird mixtures where
Speaker 1: you can add hydrogen and helium or multiple ones together.
Speaker 1: So you can look up nucleosynthesis if you're really interested
Speaker 1: in the gory details. But basically, smaller things come together.
Speaker 1: You fit these lego pieces together to make heavier and
Speaker 1: heavier things, and it gets harder and harder to do.
Speaker 1: Like you need your son to be hotter and hotter,
Speaker 1: denser and denser in order to be able to fuse
Speaker 1: to make the heavier elements. For example, our son isn't
Speaker 1: heavy enough to make oxygen. Oh, interesting, so we are
Speaker 1: not making oxygen here in our solar system. That's right.
Speaker 1: Our solar system star is not heavy enough to have
Speaker 1: the conditions to fuse carbon together to make oxygen. If
Speaker 1: you have a star that's like eight times the mass
Speaker 1: of the sun, which sounds pretty big, but it's not
Speaker 1: actually that rare because our star is not big on
Speaker 1: a galactic scale. But if you have a star with
Speaker 1: a mass eight suns or more, then it can do
Speaker 1: this carbon carbon fusion and make oxygen, and that's not
Speaker 1: that rare. So oxygen has been produced in the universe
Speaker 1: for billions of years, and there's a lot more hydrogen,
Speaker 1: but there's plenty of oxygen. Well, I guess the question is,
Speaker 1: if our son is not the one that produced the oxygen,
Speaker 1: where did it all come from? And so let's get
Speaker 1: into that question and also into other listener questions. But
Speaker 1: first let's take a quick break. All right, we're answering
Speaker 1: listener questions, and their first question came from Greg has
Speaker 1: Where does the water in the universe come from? So
Speaker 1: we know that osten is made in stars, except our
Speaker 1: star does not make oxygen. It's too wall. So where
Speaker 1: did the oxygen in our solar system come from to
Speaker 1: make all this water? It came from the same place
Speaker 1: as all the other heavier elements like the iron and
Speaker 1: all the other crazy stuff that we need to make
Speaker 1: our bodies and life. It came from other stars which
Speaker 1: were massive enough to fuse this and then died and
Speaker 1: spewed the results of their work across space. And remember
Speaker 1: the solar systems happen in waves. The first stars which
Speaker 1: formed very early after the Big Bang, and they were
Speaker 1: big and hot, and they burned very fast and burned
Speaker 1: only hydrogen. And then the second generation of stars, which
Speaker 1: had higher medallist city more of these heavy elements, and
Speaker 1: they burned helium, etcetera, etcetera. And then now our generation
Speaker 1: of stars like our sun, but we start from the
Speaker 1: endpoint of the second generation. Some of those stars were
Speaker 1: big enough to make oxygen and iron and other stuff,
Speaker 1: and so we are using those wrong ingredients formed in
Speaker 1: the fusion of other stars. So every cup of water
Speaker 1: you drink the oxygen in that was made inside a
Speaker 1: star billions of years ago, some other stars, not our stars,
Speaker 1: some other stars, some star which is no longer around. Basically,
Speaker 1: every cup of water is like a toast. You pour
Speaker 1: it out for that other star which gave its life,
Speaker 1: so you could have that drink. And where was this star?
Speaker 1: Was it like where our star is right now or
Speaker 1: from far away? That's a great question. Yeah, we know
Speaker 1: that stars tend to form in bunches, So you get
Speaker 1: these big clouds of stuff which coalesced in these star
Speaker 1: forming nurseries. And so our star was formed in a
Speaker 1: group with other stars from some huge cloud of material
Speaker 1: which came from a previous round of stars. And yeah,
Speaker 1: it was roughly around here, but now that cloud is
Speaker 1: mostly coalesced to form these stars that are our star
Speaker 1: and the neighboring stars. All right, So there was all
Speaker 1: this extra water and iron and and lithium floating around
Speaker 1: and then I guess it kind of got brought together
Speaker 1: into our solar system and our sun. Yeah, and it's
Speaker 1: not hard to make water like H two and O
Speaker 1: like to get together. If you've ever made water, which
Speaker 1: is by like combining hydrogen oxygen, it's an extremely exothermic reaction,
Speaker 1: which means it's very tightly bound. So it's not like
Speaker 1: the kind of thing that's hard to do. Like it's
Speaker 1: hard to fuse two protons together to make helium, right,
Speaker 1: doesn't even happen very often inside our star. Like a
Speaker 1: lot of times protons and protons inside our star refused
Speaker 1: to fuse. It's very low rate process, which is why
Speaker 1: are star burns for so long. It doesn't just explode,
Speaker 1: but hydrogen oxygen. They like to get together to form water.
Speaker 1: It's very tightly bound state, and so any time they're
Speaker 1: near each other, you have a few processes involved, but
Speaker 1: they very often form H two. Oh. Right, But isn't
Speaker 1: it the case that oxygen likes to form oxygen gas
Speaker 1: like O two and then then it's happy and doesn't
Speaker 1: like to interact with other things? Or does even O
Speaker 1: too love hydrogen to make water? Now you're right, you
Speaker 1: can have O two, but you have O too and
Speaker 1: hydrogen and energy around, then it will form H two. Oh. Alright, Well,
Speaker 1: I guess that answers to course and it comes from
Speaker 1: other stars. Yeah, And it's really a fascinating question, not
Speaker 1: just like where is the water, but like what kind
Speaker 1: of water is it? And how did it all get around?
Speaker 1: Because there's various flavors of water, like what coconut vitamin water,
Speaker 1: more like poisonous water and non poisonous water. Like you
Speaker 1: can have water where the hydrogen has some extra neutrons.
Speaker 1: This is called heavy water, and that you know, still
Speaker 1: water is still H two oh, but the hygen has
Speaker 1: an extra neutron and so it's a little heavier and
Speaker 1: the ratio of like normal H two O two heavy
Speaker 1: H two tells you like how it was formed, and
Speaker 1: we can see these ratios using infrared telescopes and understand
Speaker 1: like the processes that make it and the origin of water.
Speaker 1: And it's a fun question like where did water on
Speaker 1: the Earth come from? Because we tend to have very
Speaker 1: small amounts of heavy water to normal water. So there's
Speaker 1: a lot of really fun signs just about water. Yeah, yeah,
Speaker 1: I think you're telling me the other day that Earth
Speaker 1: had water initially when the rock formed together, but then
Speaker 1: it all evaporated and then we had no water, but
Speaker 1: then water came back in the form of probably comments. Yeah, exactly,
Speaker 1: we lost all of our water when Earth was hot
Speaker 1: and it boiled off, and so it had to be replenished,
Speaker 1: And so we can understand something about where our water
Speaker 1: came from by looking at these ratios and then looking
Speaker 1: out into the solar system. Is saying where do we
Speaker 1: find water with these ratios of normal to heavy water.
Speaker 1: It's a really fascinating question. Also, water does all sorts
Speaker 1: of crazy things, makes weird kinds of ices, black ice
Speaker 1: and normal ice, and man, we could do a whole
Speaker 1: podcast episode just about the weird chemistry of water, right, yeah,
Speaker 1: also coconut ice, which is delicious. All right, Well, I
Speaker 1: guess that answers Greg's question. Water in our universe comes
Speaker 1: from stars, but they have to be big stars to
Speaker 1: make them to fuse the hydrogen into helium, into carbon
Speaker 1: and into oxygen so that it can react with hydrogen.
Speaker 1: But our son does not make it, which means that
Speaker 1: our solar system came with water. It was an amenity already.
Speaker 1: That's right. And fortunately water is basically everywhere in the
Speaker 1: universe and oxygen lasts a long time, so the water
Speaker 1: that's in us might eventually one day be part of
Speaker 1: a future solar system and future life and talked about
Speaker 1: on a future podcast. Wow, same akials that that I'm
Speaker 1: spinning out right now as I'm talking might be spit
Speaker 1: out again along with some physics knowledge. All right, Well,
Speaker 1: our next question is also pretty interesting. It's a buy
Speaker 1: black holes and warm holes, and it comes to us
Speaker 1: from Hannah Hill, Daniel and Jorhee. I keep seeing headlines
Speaker 1: pop up along the lines of gamma rays from black
Speaker 1: holes could be worm holes in disguise. Now, I know
Speaker 1: from being a long time listener that these articles often
Speaker 1: aren't what they appear to be. Headlines can be misleading,
Speaker 1: so I'd really love to hear your discussion around this subject.
Speaker 1: Thank you, all right, thank you, Hannah. Awesome question. The
Speaker 1: question is do the gamma raised that you see from
Speaker 1: black holes mean that there's a warm hole inside of
Speaker 1: that black hole? And it sounds like she maybe she
Speaker 1: read it in a headline. Was there a news report, Daniel,
Speaker 1: do you remember seeing that? Yeah, a few weeks ago
Speaker 1: there was a fun new speculative paper published about looking
Speaker 1: at black holes and trying to understand the light that
Speaker 1: comes from them. And you know, the big question here
Speaker 1: is like what's going on inside that black hole? Is
Speaker 1: it a singularity like predicted from general relativity? Is there
Speaker 1: something else weird going on from quantum gravity? Are there
Speaker 1: connections to other places in the universe? And since we
Speaker 1: can't look actually inside the black hole because nothing can escape,
Speaker 1: they're hoping to look at what comes out of the
Speaker 1: black hole from nearby as a clue to understand like
Speaker 1: what's going on inside the black hole. So there was
Speaker 1: a study recently by folks who had a new idea
Speaker 1: for how to study the emissions from the stuff around
Speaker 1: the black hole to try to get a clue as
Speaker 1: to what's going on inside the black hole. Now, are
Speaker 1: we talking about a specific black hole we've seen, or
Speaker 1: is this still sort of theoretical black hole. It's theoretical.
Speaker 1: But the idea is that we could look at the
Speaker 1: supermassive black hole at the center of our galaxy called Sagittarius,
Speaker 1: a star, which is the mass of millions of suns,
Speaker 1: and it has long been accepted to be a black hole.
Speaker 1: In fact, people recently won a Nobel Prize for studying
Speaker 1: it and demonstrating that it exists and that it's a
Speaker 1: huge black hole. All right, So then the idea is
Speaker 1: that we could maybe study the gamma rays that come
Speaker 1: from the black hole at the center of our galaxy,
Speaker 1: and maybe that would tell us something about what's inside
Speaker 1: the black hole, including maybe a warm hole. Yeah, and
Speaker 1: you might be wondering, like a whole lot of second,
Speaker 1: how do you get gamma rays from black holes? Like?
Speaker 1: Aren't black holes black? And they are in fact black,
Speaker 1: Like the actual hole itself is black, nothing can escape it.
Speaker 1: The idea is that there's stuff around the black hole,
Speaker 1: and like the black hole at the center of our galaxy,
Speaker 1: there's a huge, massive stuff swirling around it that hasn't
Speaker 1: yet fallen in, and this gas is really hot and
Speaker 1: it's squeezed by the tidal forces of the black hole,
Speaker 1: and it emits a lot of radiation. And these things
Speaker 1: can be shockingly bright. They're called quasars, and there's some
Speaker 1: of the brightest things in the galaxy. Right. Yeah, we've
Speaker 1: I think we've had whole episodes on quasars and blazers
Speaker 1: and blazers also. But uh, does the black hole at
Speaker 1: the center of our galaxy have a quazer? I don't
Speaker 1: think it does, does it, or otherwise we'd be toast. Now,
Speaker 1: the black hole in the center of our galaxy does
Speaker 1: emit radiation, and that's one reason why we were able
Speaker 1: to discover we saw this intense radio radiation from the
Speaker 1: center of the galaxy. But it's not technically a quasar yet.
Speaker 1: It's not bright enough. Maybe sometime in the future you
Speaker 1: can get enough material swirling around it that it become
Speaker 1: a quasar or vention even a blazer. But that is
Speaker 1: the way that you can see black holes. You can
Speaker 1: see the hot gas around them that's emitting this light
Speaker 1: because it's glowing. Because remember everything that has a temperature
Speaker 1: will glow, all right, So there is some gas that
Speaker 1: that is emitting radiation around the black hole, and so
Speaker 1: it's the idea that then that this radiation tells about
Speaker 1: what's inside the black hole. Isn't that theoretically impossible for
Speaker 1: a black hole because you know, nothing can escape it,
Speaker 1: not even information. Yeah, the idea is to try to
Speaker 1: look for a different kind of radiation so we know
Speaker 1: about this kind of radiation. The idea is to look
Speaker 1: for a different higher energy radiation from this black hole,
Speaker 1: which might give a signal that there's a wormhole inside.
Speaker 1: And the idea is roughly like this, like what if
Speaker 1: the black hole is not just a black hole, but
Speaker 1: it's a wormhole, meaning that inside the singularity inside the
Speaker 1: black hole is connected to another black hole somewhere else
Speaker 1: in the universe. So we have our black hole the
Speaker 1: center of our galaxy. Maybe there's another black hole somewhere
Speaker 1: else in the center of some other galaxy, and their
Speaker 1: singularities are basically the same that spaces like folded or
Speaker 1: twisted or bent or just organized in such a way
Speaker 1: that those are the same place, Like they're connected to
Speaker 1: each other, right, Yeah, they're connected to each other in
Speaker 1: that the singularity would be literally the same location, like
Speaker 1: the center of our black hole would also be the
Speaker 1: center of that black hole. Like space is just you know,
Speaker 1: a bunch of locations connected. And usually you think of
Speaker 1: space being connected pretty simply, like this bit of space
Speaker 1: is connected to the one to the left of it
Speaker 1: and to the one to the right of it. But
Speaker 1: in theory you could have all sorts of different kinds
Speaker 1: of connections. You could have non simple connections, including something
Speaker 1: which is far away from something else actually being literally
Speaker 1: connected to it, right and so okay, so then the
Speaker 1: eight days that there might be a worm hole inside
Speaker 1: of our black hole and in our galaxy, and so
Speaker 1: then how could the radiation tells that there is when
Speaker 1: the next step in the idea is if you have
Speaker 1: two black holes that are connected by their singularity, then
Speaker 1: stuff falls into the two black holes, gets accelerated towards
Speaker 1: the singularities, but essentially then meets at the singularity. And
Speaker 1: then you have two black holes which essentially function as
Speaker 1: a huge cosmic collider. They're slurping in particles, speeding them
Speaker 1: up and smashing them together, forming these incredible collisions which
Speaker 1: could release a mos amounts of energy. Right, But could
Speaker 1: those flashes of energy escaped a black hole. I thought
Speaker 1: nothing could escape a black hole. Yeah, And that's the
Speaker 1: part of the study which I just do not understand,
Speaker 1: because they do these calculations. Are read their paper, and
Speaker 1: they predict that you could form gamma rays at a
Speaker 1: different energy. Like the plasma balls that are created at
Speaker 1: the center of these black holes are super duper hot.
Speaker 1: It's like eighteen trillion degrees, and so in theory, the
Speaker 1: photons that come out of those have different wavelengths than
Speaker 1: the photons you normally get from black holes. But the
Speaker 1: thing that doesn't make any sense to me is how
Speaker 1: do they get out of the black hole at all?
Speaker 1: If you have two black holes connected with the singularity. Sure,
Speaker 1: you might have a super collider creating these crazy collisions
Speaker 1: at the center, but they're not going anywhere. You need
Speaker 1: a third black hole or a white hole. You would
Speaker 1: need a white hole exactly. And so some wormhole configurations
Speaker 1: are two black holes meeting at the singularity. And in
Speaker 1: my understanding, that doesn't make any sense to talk about
Speaker 1: things leaving those black holes, because there are two black
Speaker 1: holes and the thing can leave them. Another configuration for
Speaker 1: wormholes is you have one black hole and one white hole.
Speaker 1: And things fall into a black hole and things leave
Speaker 1: a white hole. The white hole is the opposite of
Speaker 1: a black hole. A black hole is a place where
Speaker 1: nothing comes out and things only fall in. A white
Speaker 1: hole is a place where things come out and nothing
Speaker 1: can fall in. So things could get sucked into a
Speaker 1: black hole and spewed out a white hole, but those
Speaker 1: wouldn't give you the collisions. To get the collisions, you
Speaker 1: need two black holes linked, which means you can never
Speaker 1: see it. As far as I understand, there's a fundamental
Speaker 1: problem with this idea. So this paper that came out,
Speaker 1: you don't see it working, like, you don't see how
Speaker 1: it makes sense. No, it doesn't make any sense to me.
Speaker 1: And I actually reached out to some theorists and some
Speaker 1: quantum gravity folks, and it didn't make sense to them either,
Speaker 1: And so I think, you know, this is a fun
Speaker 1: speculative idea, And maybe they got as far as, oh,
Speaker 1: this would be cool. You could create these plasma balls
Speaker 1: at eighteen trillion degrees inside the heart of black holes,
Speaker 1: but they haven't actually figured out how to see them,
Speaker 1: how to get them out. Yeah. Yeah, So the paper
Speaker 1: itself is a black hole. It doesn't go anywhere. It's
Speaker 1: a fun idea. Nothing useful comes out of it. It's
Speaker 1: a fun idea to think about what happens inside a
Speaker 1: black hole. Like maybe they're eighteen trillion degree plasma balls,
Speaker 1: or maybe there aren't. Maybe they're pink dinosaurs. Who knows,
Speaker 1: but as long as they're inside the black hole, we
Speaker 1: really have no chance of seeing the interesting. All right,
Speaker 1: So that's the answer for Hannah. The paper is that
Speaker 1: it doesn't quite make a lot of sense to most
Speaker 1: physicists because you couldn't get any gamma rays that come
Speaker 1: out of the black holes that would tell you anything
Speaker 1: about what's inside, because nothing can come out of black holes. Yeah, exactly,
Speaker 1: So until then we have to continue to study black
Speaker 1: holes using only the stuff that's near them, that's around them,
Speaker 1: that's a strong gravitation of probe what's going on inside
Speaker 1: the black hole without actually being inside the black hole, right,
Speaker 1: or somebody could go in and check it out, we
Speaker 1: would never know. We never know what they find out exactly.
Speaker 1: They'd be having plasma balls for lunch, but we would
Speaker 1: never know. Man said, all right, let's get into our
Speaker 1: last question of the episode, and it's a question about
Speaker 1: dark matter. But first let's take a quick break. All right,
Speaker 1: we are answering listener questions and we have one more
Speaker 1: question here from Matt Hatton about dark matter. Hi guys,
Speaker 1: my question for you is if I gave you a
Speaker 1: container with some dark matter inside, what experiments and tests
Speaker 1: would you perform on it? Alright, awesome question, Matt, Thank you.
Speaker 1: The question is what would you do with a box
Speaker 1: of dark matter? Like if somebody gave you like here here,
Speaker 1: here's some dark matter and they tell you for sure
Speaker 1: that there was dark matter in it? What kind of experiment?
Speaker 1: Or are fun games or I don't know what would
Speaker 1: you dip in it and to eat? I don't know what?
Speaker 1: What would you do with it? What would a physicists
Speaker 1: do with a box of dark matter? Do you think?
Speaker 1: Matt actually has the box of dark matter? And he's
Speaker 1: like running a contest. He's like, who's got the best
Speaker 1: idea for what we should do with my dark matter?
Speaker 1: Winner gets the box. This is a wonderful question. I
Speaker 1: love this question. It got me excited. I was like,
Speaker 1: what would I do with the box of dark matter?
Speaker 1: I can do this or I can do that. It's
Speaker 1: a fun idea, right, Well, I guess first of all,
Speaker 1: you kind of have to ask what would the box
Speaker 1: be made out of, because if it's made out of
Speaker 1: regular matter, it would just let all the dark matter escape. Yeah,
Speaker 1: there's a lot built into this question, right, he has
Speaker 1: a container of dark matter. He has some box which
Speaker 1: can contain dark matter. And remember, dark matter, we know
Speaker 1: that it's out there, we know it's a thing, we
Speaker 1: know it's matter, we know it has gravity, as far
Speaker 1: as we know, has no other way to interact. It
Speaker 1: doesn't give off light, doesn't reflect light, doesn't bounce off
Speaker 1: things using electromagnetic forces or the strong force or the
Speaker 1: weak nuclear force. That means that if you have made
Speaker 1: a box out of some super strong material, dark matter
Speaker 1: would just pass right through it because gravity is a
Speaker 1: super duper weak force. If you only interacted with gravity,
Speaker 1: you could walk through walls because gravity is so weak
Speaker 1: that the gravity of the wall would never stop you
Speaker 1: passing through it. Your molecules would pass right through the
Speaker 1: wall just the same way for example, the new trinos
Speaker 1: or muans passed through the wall. And so what container
Speaker 1: could you make that could possibly contain dark matter would
Speaker 1: have to be like made out of like a super
Speaker 1: strong anti gravity or something even then like it would
Speaker 1: have to be incredibly dense to build like a gravitational
Speaker 1: well capable of containing dark matter. You know, even our
Speaker 1: galaxy is not great at containing dark matter. There's a
Speaker 1: huge amount of dark matter in our galaxy, but it's
Speaker 1: mostly fluffy and diffuse because gravity is not strong enough
Speaker 1: to pull it down together, and because dark matter has
Speaker 1: no way to sort of like lose energy. It can't
Speaker 1: like radiate away energy or collide with itself and give
Speaker 1: up some energy, and so it mostly stays fluffy. Even
Speaker 1: gravity is not very strange. But let's say, for example,
Speaker 1: that we had a blob of dark matter. Don't worry
Speaker 1: so much about the container. Let's just say somebody figured
Speaker 1: out there's a blob of dark matter right here, what
Speaker 1: would you do with it? And, like you said, would
Speaker 1: be really diffused, right, because I think we mentioned in
Speaker 1: the podcast was that all the dark matter on Earth
Speaker 1: that covers the same volume as Earth would only be
Speaker 1: about as much as a squirrel. Right. Yeah, there's a
Speaker 1: lot more dark matter in our galaxy than anything else,
Speaker 1: but it's much more spread out than normal matter, Like
Speaker 1: there's not that much normal matter if you consider all
Speaker 1: the huge amounts of space in our galaxy, right, there's
Speaker 1: really massive stars, but then light years of space in
Speaker 1: between them dark matter. There's a lot more of it,
Speaker 1: but it's more evenly spread out. And so like you
Speaker 1: pick a random cubic meter of space that has one
Speaker 1: or two proton mass is worth of dark matter. And
Speaker 1: so yeah, if you integrate over the volume of the Earth,
Speaker 1: you get about the mass of a score. Right, So
Speaker 1: there's just not that much dark matter like in our neighborhood.
Speaker 1: It also means that all boxes on Earth really have
Speaker 1: dark matter in them, So like every box is a
Speaker 1: box of dark matter. That's right, you are a box
Speaker 1: of dark matter. I mean that in the nicest way possible.
Speaker 1: Thank you. I like to think I'm in better shape
Speaker 1: than square box. But you're a very trim box of
Speaker 1: dark matter. All right, there you go. Yeah, alright, so
Speaker 1: every box is a box of dark matter. But if,
Speaker 1: like I guess, the question is like, if you could
Speaker 1: somehow contain it or group it together in front of
Speaker 1: you in a lab, what kind of experiment would you
Speaker 1: do with it? So that really the only thing you
Speaker 1: can do in these kind of experiments is to try
Speaker 1: to interact with the dark matter, and you can go
Speaker 1: one of two routes. Really one is use gravity. You
Speaker 1: know that it interacts gravitationally, So what you could try
Speaker 1: to do is build like a really sensitive gravitational probe.
Speaker 1: You know, you could have like heavy masses nearby. You
Speaker 1: can try to study like the push and the pull
Speaker 1: on those masses to try to get a sense for
Speaker 1: like what's going on inside this blob. Is it just
Speaker 1: totally smooth to have some sort of structure, Is it's
Speaker 1: swirling around. You could try to use its gravitational information
Speaker 1: by putting heavy masses around it and then watching the
Speaker 1: effects on those masses. That sort of idea Number one.
Speaker 1: Oh interesting, Like if you had a really dense cloud
Speaker 1: of dark matter, you would feel maybe a lot of
Speaker 1: gravity outside of it, but once you go into the cloud,
Speaker 1: you would not feel gravity because it's all around you exactly,
Speaker 1: And you can use that to sort of like map
Speaker 1: out exactly where is the dark matter in this cloud.
Speaker 1: You know, gravity is really really weak, which makes these
Speaker 1: experiments really hard, but we can measure the gravity between
Speaker 1: sort of like non planetary size blobs of stuff. You
Speaker 1: can take like an iron ball and another iron ball
Speaker 1: and put them near each other, and you can measure
Speaker 1: really small deflections in their motion from the force of gravity.
Speaker 1: So if you do really really sensitive gravitational experiments, you
Speaker 1: could get sort of like a map of where the
Speaker 1: dark matter is in this blob and maybe over time
Speaker 1: what it's doing, and that could give you a sense
Speaker 1: for like is it swirling, is it just sitting there?
Speaker 1: Is if forming structures? Is it like sending you a
Speaker 1: message that would give you some sense, or just where
Speaker 1: it is? Does it look like a squirrel? A lot
Speaker 1: of important questions? What if it is just dark squirrel?
Speaker 1: So one experiment you would do is you would stick
Speaker 1: in maybe like a heavy iron ball inside of it
Speaker 1: and wave it around to try to like map it
Speaker 1: like see evens clumping or swirling or is it pretty even? Yeah?
Speaker 1: Or maybe like a whole grid of iron balls and
Speaker 1: look for any deflections on any of them to give
Speaker 1: like a three D map for its location and its motion.
Speaker 1: All right, So that that you said, that's one kind
Speaker 1: of experiment. What's another kind of Well, the other and
Speaker 1: maybe much more interesting is to try to figure out
Speaker 1: if it has any other kinds of interactions. You know,
Speaker 1: really the deep question about dark matter is what is
Speaker 1: it made out? Of is it made out of some
Speaker 1: other kind of particle or non particle or some other
Speaker 1: new kind of stuff. And if it's made out of
Speaker 1: a particle, it might have some other kind of way
Speaker 1: of interacting, maybe some new force that we haven't discovered yet.
Speaker 1: You know, we know about several forces in the universe
Speaker 1: electro magnetism, gravity, and strong and weak nuclear force. That
Speaker 1: doesn't mean that there's not another force. That's just a
Speaker 1: list of sort of what we've seen so far. But
Speaker 1: dark matter is something new, and so it might also
Speaker 1: have a new kind of force. Now to see that,
Speaker 1: you'd have to have some kind of material that also
Speaker 1: feels that force. So we'd have to have some new
Speaker 1: kind of force that's felt both by dark matter and
Speaker 1: by our kind of matter. So basically, in the end,
Speaker 1: which you do is you shoot particles into this blob
Speaker 1: of dark matter and you look to see if they're deflected,
Speaker 1: and you hope eventually to see one sort of like
Speaker 1: bent sideways or you know, careening off in a new direction,
Speaker 1: and that would tell you, oh, my particle bounced into
Speaker 1: the dark matter and came off, And you could measure
Speaker 1: the rate at which that happens. An angle which it
Speaker 1: deflects and get a sense for how strong is that
Speaker 1: new kind of force. And so you would take this
Speaker 1: volume of dark matter and you would put it maybe
Speaker 1: in the path of the large catron collider ring. Would
Speaker 1: that work? Would that help you if you shoot all
Speaker 1: those proteons at it or with protons not work? Yeah,
Speaker 1: that's a great idea. Protons are a good idea because
Speaker 1: protons of lots of different kinds of interactions. You might
Speaker 1: also want to try electrons. You might want to build
Speaker 1: a lot of colliders and shoot all sorts of different
Speaker 1: stuff at it because you have no idea what's going
Speaker 1: to feel this new interaction, right, protons of interactions that
Speaker 1: electrons don't like a strong interaction. But maybe electrons have
Speaker 1: interactions of protons don't that we aren't aware of. So
Speaker 1: you want to try a bunch of different stuff. So basically, yeah,
Speaker 1: you want to zap it with a bunch of different
Speaker 1: kind of beams and see if you can see any
Speaker 1: kind of response. But you know, so far people have
Speaker 1: been looking for dark matter and lots of different ways.
Speaker 1: But we've been trying varieties of this kind of experiment
Speaker 1: in lots of different ways. You know, we have huge
Speaker 1: masses of quiet protons sitting underground waiting for dark matter
Speaker 1: to bounce into them, sort of the reverse of this experiment.
Speaker 1: We have winds of dark matter we think are passing
Speaker 1: underground through the Earth, hoping to hit one of our detectors.
Speaker 1: We haven't seen anything yet, and so it might be
Speaker 1: that we just don't have a powerful enough wind of
Speaker 1: dark matter. And if you had a really dense blob
Speaker 1: and you hit it with a really powerful beam, you
Speaker 1: might start to see something. But those experiments are already
Speaker 1: sort of just giving no result, not seeing anything, so
Speaker 1: I wouldn't be too hopeful. So really, you you just
Speaker 1: maybe put it up on your mantle and admire it,
Speaker 1: because that you can't really it seems like it doesn't
Speaker 1: seem likely that we can get to make an experiment
Speaker 1: that would tell us much about it because it doesn't
Speaker 1: interact with our kind of matter. Yeah. Well, there's one
Speaker 1: sort of last idea, which is sort of only a
Speaker 1: half idea, which is like, yeah, put it on your mantle,
Speaker 1: but also watch it carefully because it might be that
Speaker 1: dark matter does something interesting and if you make enough
Speaker 1: of a dense blob, maybe it has some kind of
Speaker 1: self interaction. Right, maybe it doesn't interact with our kind
Speaker 1: of matter, but maybe it has some kind of self intera. Actually,
Speaker 1: they can do something interesting and it might eventually emit
Speaker 1: something which we can detect. So maybe over a long
Speaker 1: enough time periods and great enough densities that dark matter
Speaker 1: could send us a signal. And so another idea is
Speaker 1: just like build a bunch of detectors around it and
Speaker 1: keep an eye on. What if you split it in
Speaker 1: half and then collided them together. How would you do that?
Speaker 1: How would you accelerate dark matter? Right? Well, I mean
Speaker 1: if we're talking about heavy iron balls, could could you
Speaker 1: use gravity somehow to accelerate them? You could use gravity.
Speaker 1: Gravity is the only handle we have, but it's difficult
Speaker 1: to build a gravitational accelerator to create, like, you know,
Speaker 1: a black hole in between the dark matter. Um, so yeah,
Speaker 1: maybe the gamma rays would help us. Yeah, sure, exactly,
Speaker 1: that's not a terrible idea. I like it. Let's build
Speaker 1: a black hole and then when people come and ask
Speaker 1: why we suck the Earth into a black hole, will
Speaker 1: say it's because of Matt Hatton's experiently thank you Matt,
Speaker 1: before are destroying the planet Earth. His fault, but maybe
Speaker 1: we learned something on the way. All right, Well that
Speaker 1: answers Matt's question. I think which is it? You would
Speaker 1: try to probe it and you would try to do
Speaker 1: experiments on it and see if it can react to
Speaker 1: anything that we know. I wonder if he was hoping
Speaker 1: for a more fun answer, like you would maybe dip
Speaker 1: bananas in it, or I don't know, what's the fun
Speaker 1: thing you would do with the box of dark matter?
Speaker 1: To any I would eat it. That's the thing about
Speaker 1: his question is I think it's trying to touch on
Speaker 1: this thing, like why can't we figure it out? What
Speaker 1: would you do if I just gave you some? And
Speaker 1: the problem is matth that we already have lots of
Speaker 1: it around us and we're doing everything we can to
Speaker 1: interact with it, and nothing is responding. And so the
Speaker 1: problem for understanding what dark matter is not finding dark matter,
Speaker 1: is not giving access to it. It's just getting it
Speaker 1: to respond to anything that we've tried. It's very squirreling,
Speaker 1: it's very snobbish, and it's nut. Alright. Well, those were
Speaker 1: all our listener questions for today. Thank you so much
Speaker 1: to Greg, Hannah and Matt for asking the questions and
Speaker 1: sending them in as usual. We love answering these questions,
Speaker 1: and if you have questions about the universe or questions
Speaker 1: you'd like to have us breakdown, please don't hesitate. Send
Speaker 1: them into questions at Daniel and Jorge dot com. You
Speaker 1: might get an email back from me or you might
Speaker 1: get an answer on the podcast, so stay tuned for
Speaker 1: more listener questions in the future. Until then, thanks for
Speaker 1: joining us, See you next time. Thanks for listening, and
Speaker 1: remember that Daniel and Jorge Explain the Universe is a
Speaker 1: production of I Heart Radio. Or more podcast from my
Speaker 1: heart Radio visit the I heart Radio app, Apple Podcasts,
Speaker 1: or wherever you listen to your favorite shows.