Ologies with Alie Ward - Cosmology (THE UNIVERSE) with Katie Mack, Part I

Episode Date: December 12, 2017

Stars. Black holes. THE GAWDANG UNIVERSE. Astrophysicist and cosmologist Katie Mack (@astrokatie) joins to tell us her most embarrassing moments as a cosmologist, to debunk some physicist myths and give the nuts + bolts of everything form particle physics to gravitational waves and existential mysteries. Walk away with cocktail party comprehension of everything from the itty-bitty quarks that make you to the neutron stars banging together across the cosmos. More than anything, get perspective about your life on this, our little pale blue dot.Follow Katie Mack on Instagram and TwitterMore episode sources & linksSupport Ologies on Patreon for as little as a buck a monthOlogiesMerch.com has hats, shirts, pins, totes!Follow @Ologies on Twitter and InstagramFollow @AlieWard on Twitter and InstagramTheme song by Nick Thorburn

Hey, welcome to oligies. I'm your LA ward the host now each week. I sit down with an oligist I ask why do they love what they do? What is your deal? What should we know about it? And this week we cover The whole fucking universe which has Existed and it's expanding and you're floating in it and you're made out of particles and matter and forces We don't even understand and maybe there are multiverses and is this reality? And what are you doing here? And does anything matter? And of course it does But should you be afraid of wearing bright lipstick or dancing in public? Probably not. No in the scope of things and the scope of things is Really, it's giant. It's called

Cosmology now if you think that you listen to this episode already because you learn some stuff about beard care and face wash think again suckers That was cosmetology this week is cosmology the study of the cosmos and So when I say this episode is like everything It's actually everything. It's the whole universe. It's it's a lot It's a lot. It's so much. It's a two-parter. It's a two-fer so this week we'll get the nuts and bolts of what astrophysics is and After about an hour you will walk away cocktail party literate on goddamn Astrophysics kind of I don't know I'm learning here with you of all the episodes I've done

This was probably the one I need the least about so let's learn together Shall we part two of this next week are your questions submitted via patreon and the oligies podcast Facebook group y'all had good ones Next week will address them now the etymology of cosmology Cosmos with a K is the kiki little Greek word for world or order So cosmology is a study of planets and such sure But also why and what and how where what huh? It's a study of what? This week's cosmologist is someone I've had a fawning Twitter fascination with for a while and I met through a group of science friends

I love known to some as the nerd brigade or kind of like a gang but with a website But I was always kind of intimidated by her because she is in her own words an academic nomad And she continent hops while studying particle physics and black holes and gravitational waves and she hangs out with Stephen Hawking So when I met her through friends I usually just sat at brunch like a barnacle and tried to look away when she caught me staring at her So I asked her to be on the podcast She said yes, and I immediately started perspiring So she came to my apartment

We sat down and my usual hour interview stretched to almost two hence the two-parter Hours before she politely reminded me that we were supposed to be meeting people for a movie and we should stop I'm so so glad we did this podcast because I got to know her even better as a friend Which y'all I'm gonna be cheesy and say it's a true honor So in this episode you'll learn about the things that make you you and the stars that Exploded to make the things that make you you and the scale of our existence in space and what it feels like to be heckled by Stephen Hawking And if this is real life and if astrophysicists are just like making bullshit up that the rest of us just accept because we're like Man, I don't even know how to read these equations. So okay

So you'll get at the very least a loose grasp on just the whole of existence and maybe steal yourself to be the biggest you You want to be and more importantly get to know better one of the world's finest voices in cosmology You know her as Astro Katie on Twitter aka astrophysicist Katie Mack So take me back. Yeah to defining some stuff because as a layman as a laywoman over here mm-hmm a lay human. Yes, I Don't know the difference between a physicist an astrophysicist a particle physicist an experimentalist a cosmologist and an astronomer I don't know what those are and I'm either gonna have to wikipedia this or I can have you give me a rundown So these things are they're a little bit like fluid these definitions so

astronomer is basically somebody who studies space in some way and usually when people say astronomer versus astrophysicist Usually astronomer is like more on the observational side or Sort of describing stuff in space astrophysicist is more about like trying to understand how the physics of the thing in space works So you can be an astrophysicist trying to understand how galaxies form for example, and so you're applying physics to this stuff in space

if you're a particle physicist you're working on Like how particle interactions work so like you know atom smashers and things large Hadron collider expose on Usually I mean the the like Classic particle experiment is you take two particles and you smash them together and you see what comes out That's what the large Hadron collider is doing now the LHC That's what you call the large Hadron collider when y'all are tight So you've maybe heard of it. You kind of know like it's a thing in Europe Maybe has something to do with atoms. I looked into it

The large Hadron collider is located near the France Switzerland border, and it's a circular tunnel It's over 500 feet deep in some parts and it's 17 miles around It is the largest machine in the world So this thing consists of over 1200 magnets and they're cooled to a temperature colder than outer space and then the magnets Accelerate protons to almost the speed of light and then the protons are bashed together. It's very punk rock very Expensive the LHC was mostly completed in 2008 over 10,000 scientists and engineers worked on it now in photos It looks kind of like a giant well-lit subway tunnel

But with less pee and rats if you're like I can't remember what a proton is because I'm not required to anymore I'm not in school. Don't worry. Neither did I it had to Google like how does an atom work? I forgot so I'll brush you up. So matter is stuff and molecules are some atoms stuck together Atoms are made of a nucleus which is a little cluster of neutrons and protons protons have a positive charge pro electrons have an equal Negative charge and electrons are bebop and zoom it around Whirling derbish style outside of the nucleus so the neutrons and protons which are the ones that are just cuddling in

The nucleus those are made of smaller particles called Quarks and the quirks come in a couple different varieties. So what gives these particles their mass What are they? Where do they come from? We've got all these little tiny things that make up matter Okay, so I heard it explained that there's a field called the Higgs field It's named after one alive and well Scotsman physicist named Peter Higgs and How a particle interacts with the Higgs field gives it its mass kind of like drag in water So Higgs bosons are particles. They're an excitation of the Higgs field It's kind of like a drop of water splashing from an ocean

So the large Hadron collider smashed protons together to see if they could prove that the Higgs boson exists and guess what? Bitches it does. You're not bitches Some people call this the God particle because it's so fundamental to all matter in the universe Does Dr. Higgs like this name? No, he's an atheist He thinks it sucks and the guy who coined it the God particle actually wanted to call it the goddamn particle But his publisher made him change it in a book So the large Hadron collider one of the things it does Smashes these protons together into smaller things to figure out why matter has mass

There you go. Also the large Hadron collider Accidentally has its name spelled wrong on its own website as large hard-on collider once would be mortifying, but like what if they did it more than once like twice or Five times. That's impossible. Is it because a search on their site revealed they'd spelled it large hard-on collider 165 times Thank God particle for that. That's just precious. So whenever you're like, I don't understand this stuff Maybe I'm not smart enough. Just think someone typed in large hard-on collider

Over 150 times and they built the thing So how else do people figure this shit out about very important things that we can't see but there are other ways to do particle physics Measuring how particles interact with each other Throwing particles at other things Accelerating stuff and seeing what happens all of that kind of stuff on the experimental side and on the theory side It's a lot about trying to understand like the fundamental forces of nature. So like how how atoms hold together how

You know particles can change into other particles in certain conditions How gravity fits into all that which it doesn't at the moment theoretically, okay? I mean it doesn't it's very hard to get gravity and particle physics to work together This is kind of yeah, it's it's sort of this may be another topic But like this is the the reason string theory was invented real quick. What is string theory? Well in a very cork-sized tiny nutshell the premise of string theory is that basic objects are not Point-like, but they're string-like. So a cork might be made of a loop that kind of vibrates and moves around Every kind of particle is like a different wiggly string. So why does anyone care? Why are people so horny for string theory?

Well number one it's from the 80s and maybe this is like the scrunchie of particle physics I don't know more importantly string theory is a theory that works with both Einstein's general relativity and that Mr. Einstein pose that what we perceive as the force of gravity is is the curvature of space and time more on that in a minute and Quantum mechanics, which is the physics of the tiniest building blocks that exist So remember those quirks that made up protons and neutrons. What are those made of maybe these string-like? Loops of matter every time I hear string theory mentioned I think of string cheese. I cannot and I was writing and researching this episode and my I found myself on a website Like 2 30 in the morning learning that string cheese as we know it was invented in Wisconsin in 1976

And the way they get it to string is to heat it to a hundred and forty degrees Fahrenheit and that aligns all the milk proteins Also, the first iterations of string cheese were bigger and chunkier and served to drunks in bars Should we get back to physics? Okay. I'm sorry and this is like the big question in physics is that like so they're There are a few sort of fundamental forces of nature, right? There's electromagnetism there's that and that's like light and you know like static cling and and all of those kinds of things right and and

Magnetism and then there's the weak nuclear force which has to do with like how particles decay in radioactivity that kind of thing And how particles can change into other particles under certain conditions There's the strong nuclear force and that holds particles together in the centers of atoms. Okay And those all kind of make sense together theoretically like you can write down equations that Make those all fit in some way More or less when Katie says You can write down equations that make those all fit. I appreciate her being inclusive with the second person But I I cannot write down equations to make those all fit in some way. I

Cannot do that, but then there's gravity and gravity just doesn't follow any of the same rules It's like it's very hard to put together a theory that includes those the the fundamental forces of particle physics and gravity So it's gravity like the bad boy in a teen drama. It's just like it's just not following any rules. It's weird It's like like gravity is all about space-time, you know So gravity like so the theory of gravity that we have is Einstein's theory of relativity so general relativity. This is the theory of gravity where okay get ready Here's Einstein. Here's how the universe of which you are a part works

The Bay the basic picture is that you can think of space as this malleable thing And if you have something that has mass it creates like a dent in space it sort of bends space around it okay, and And so other things moving past will respond to that and like fall into that dent That's like how gravitational attraction works. You can think of it in this geometric way Okay, and it works really well like geometrically to think of it like that But then there are fundamental principles that happen in that like the speed of light as a limiting factor and All sorts of things like that. So only certain paths things can follow and everything

But then the particle physics stuff like all the equations of particle physics are done without Thinking about gravity because on those scales like gravity isn't important. It's a really really weak force. Okay but also like there are the way that the Particle physics is is formulated in the standard model of particle physics, which is what we use to talk about all these interactions it doesn't have the same like It doesn't follow the same rules as gravity like there are ways in which the whole like Speed of light thing is violated in one way that you can formulate how particles move around Which is kind of like there's kind of like there's this way of formulating it where a particle going from point A to point B

passes through every possible path on the way between point A and point B and it's only by by Using that idea that you get the right answer for how that particle is moving in the particle physics point of view Mm-hmm, and that doesn't work with relativity So there are a couple of things like that where like quantum mechanics and relativity Just do not like each other really and and it gets especially Problematic when you get to black hole because a black hole is this very like intense gravitational system Mm-hmm. It's basically a dent in space time. That's so deep that like everything falls into it if it gets close enough

but at the edge of a black hole the event horizon you have this weird quantum mechanical thing happening where you can have like particles evaporating off of it and that sets like a sort of scale of the black hole and That means there's quantum mechanics Happening in a strong gravitational system and then just everything breaks and just goes totally haywire because If you look at it from a gravitational point of view like a relativity point of view You should see nothing at all interesting happening when you when you fall into the black hole like aside from like you're you're killed by the gravity

But like you don't see like nothing weird happens when you pass the horizon but from a particle physics point of view like There there might be like this like firewall like there might be like a sort of like Boundary of intense radiation there because of the way you have to think about how the particle physics works. This is a complicated story, but But basically there's like Astrophysics typically is yeah, I'm not explaining it very well But but basically like

Like basically when you get to that point when you have a black hole it has an Evaporation happening where particles are coming off the edge of the event horizon One way of looking at it says that that means that Whatever you fall through into the black hole you can't ever find out what it was that information is destroyed But quantum mechanics like the particle point of view says you can't do that And so there has to be some kind of loophole and then gravity doesn't like that and you just you just end up with chaos And so there's this there's this big problem called the black hole Information paradox which has been around forever and every once in a while somebody's like oh, I've solved it

And then it's really complicated and people don't really understand how that works. Has anyone actually solved that I mean I So technically I'm just not qualified to know that for sure because it's it requires Understanding quantum gravity in a way that I do not But there have been some solutions suggested but in in general there's still a lot of discussion So I don't know okay wait, so what does a cosmologist do the cosmologist just means you study The universe as a whole right? So you study maybe the beginning of the universe the end of the universe how it changes over time But you can be a physicist's cosmologist or an astronomer cosmologist and those are different

and and It's culturally different like but the so if you're if you're a physicist if you if you hang out with particle physics people and you say you're a cosmologist then then the implication is that you work on like the the beginning of the universe and the forces of nature and Maybe the end of the universe something like that if you hang out with astrophysicists, and you say you're a cosmologist Then you just study things that are really far away or you study, you know Some something you know more fundamental

But like you can be a cosmologist in astrophysics and you're a cosmologist because you study very very distant galaxies The reason that counts as cosmology is because that means you're studying the very distant past of the universe So there are different flavors of cosmology, but they're all kind of linked at least in my opinion by like oh, where are we? What are we? What are we made of aka? It's a branch of astronomy that involves the origin and evolution of the universe That's a less panicky way to put it and so So that so then you're studying like how the universe has changed over time

So they're kind of different ways of doing it and I've done all of those different kinds of cosmology, I guess because I've Spent my time kind of bouncing back and forth between the particle physics and the astrophysics communities So I've worked on you know the the big bang and like theories of the early universe and I've worked on distant galaxies and how galaxies form and I've worked on black holes and weird stuff like cosmic strings and just All sorts of things. What is a cosmic string a cosmic string is kind of like a

Sort of line or wiggly line of energy that stretches across the cosmos might not exist Probably doesn't exist, but there could be this like whole network of strings of like it's it's it's kind of like if you think of like a Black hole, but you like stretch it out across the whole universe. You get it's kind of like that. What does it do? What it so really interesting things so if you have two cosmic strings and they cross each other They collide they can like reconnect in a different way So you can have two cosmic strings that are about to collide and then they they like change so that now you have two sort of Loops of cosmic strings. They're going in opposite directions Like so they sort of pass through each other by branching off in this weird way

So cosmic strings may or may not exist now if they do exist Some theorists have used them To maybe sketch out some stuff about time travel Please forget it out. Please fix some stuff. Thank you And you can make a loop of cosmic string and then that loop of cosmic string will like wiggle around and make gravitational radiation and and disappear into nothingness and if you have a cosmic string like if you have a cosmic string between you and some distant galaxy

Then you might see two pictures of that galaxy because it like splits the space kind of It's really cool. Now. How much do you think about all of this in your day-to-day life? And like when you're deciding if you should upgrade your rental car and like If you should cut bangs and what happens to your molecules after you die like how much do you let this kind of get to your own existence? Yeah, somebody asked me that the other day like how much do I like Get sort of just overwhelmed by these ideas or whatever It's not very often like most of the time this is like this is fun stuff to work on but like most of this time it feels more like

Some kind of combination of science fiction and a fun puzzle, you know, so like I'm trying to solve a problem I'm trying to calculate something and trying to come up with a new idea for how to do something and So it's like a puzzle. It's like some kind of neat thing to work out And I don't think of it as connecting to my own life or existence because it's way far away or way in the past Or, you know, probably doesn't exist or whatever, right? But then every once in a while like I'll be I'll be thinking about this stuff and I'll be like, oh my god, like there's Stuff is out there Like I'll be thinking about black holes or

Gravitational waves or like the inflation period in the early universe or something like that And I'll be like, I'll have to like hold on to something and be like, oh god Because these are huge like mind-bendingly intense forces and massive things and like the kinds of energies and the kinds of like force and just I Don't know the explosions and everything. It's just we cannot comprehend this stuff I mean the earth is is really tiny and really unimportant like in a big way. So so okay You know, there's there's this

There's this famous Photograph the pale blue dot. Yes. Yeah. So this is a picture that was taken by the Voyager spacecraft So the pale blue dot photo was taken on Valentine's Day in 1990 as Voyager 1 Was leaving the solar system. It was like bye-bye. I'm out and Astronomer Carl Sagan said yo, let's turn that lens around. Let's take a pic of all of us far away What do you say might as well? And it was 3.7 billion miles away

It's little galaxies longest range selfie this photo itself It looks like you accidentally took like a blurry image of a few Christmas lights And there was like a speck of dust on your lens those lights are just a few scattered rays of Sun and Someone would have to point out that that dust is our planet is such a Tiny speck and I'll let Carl Sagan put this in context. He's the pro here That's here That's home That's us

on it everyone you love everyone you know Everyone you ever heard of every human being who ever was lived out their lives The aggregate of our joy and suffering Thousands of confident religions ideologies and economic doctrines Every hunter and forager

Every hero and coward every creator and destroyer of civilization Every king and peasants Every young couple in love every mother and father hopeful child Inventor and explorer Every teacher of morals every corrupt politician every Superstar every Supreme leader every saint and sinner in the history of our species

lived there on a mode of dust suspended in a sunbeam The earth is a very small stage in a fast cosmic arena Sometimes when I give talks about cosmology, I'll end with this picture and I'll be like, you know Just thinking about how vast the universe is and how really insignificant we are and it's and

The insignificant it says is even deeper than just what you see from that picture because in that picture You see like there's a whole lot of empty space and then there's a little tiny rock Yeah, and we're on that little tiny rock right boy, and there's a lot of space, but it's even worse than that because Because like not only are we not the center of like the universe or a galaxy or a solar system or anything like that the matter that we're made of is also really unimportant because Because like just the kind of stuff that we are and that we can understand and interact with Regular matter is like five percent of the universe So most of the universe is something called dark energy that we really don't understand

But it's some sort of mysterious stuff that's making the universe expand faster and faster It's gonna take over eventually and then there's dark matter Which is some kind of invisible matter that is most of what the galaxy is made of and most of what all galaxies are made of So like our galaxy, you know We think of it as like this pretty disc of stars But it's actually in embedded in this invisible blob of Extra stuff that we can't see and that blob is way bigger than the stuff that we can actually see So dark matter is like eighty five percent of the matter in the universe or something like that

Oh my god And then dark energy is like seventy percent of all of the stuff in the universe like so so then we're this like Little tiny five percent size and that's just the kind of matter that we can understand that we can do experiments on that We can see or touch or interact with in any reasonable way and Then it's like not only Not only are we like a tiny speck of dust on a tiny speck of dust like it was you know like We are so insignificant like the universe doesn't even it doesn't even matter that were like that our kind of stuff is there You know the best thing about this conversation is yeah

I'm having it with a cosmologist and like an astrophysicist But I could also be having the same conversation with any of my college roommates Like a seven-foot bong in the in the garage when astrophysicists and cosmologists get together Yeah, is it just kind of like a round robin of like stoner existentialism like cuz I feel like there's such a fine line like and then You're either Incredibly incredibly Smart and thoughtful and knowledgeable about this stuff or you're just like you've just numbed yourself enough for you allow yourself to Think about it and then and it's like the bell curve. This is big white swath of people who are like I can't even think about it

It's too much, you know, I mean So when when I do get together with other cosmologists and we talk shop It's usually very very technical and so we don't get into this stuff at all Like where it's it's usually, you know, we're just talking about We're talking in a lot of jargon about like some measurement or something and we're throwing out numbers And we're trying to like figure out like is this a reasonable measurement to make or whatever or like what what kind of plot can we make to You know to illustrate this point or what kind of calculation should we do or like what's the important variable it? It would not be interesting to

Somebody who is not in the field So it's really only when I'm talking about people are not in cosmology where like I have these moments of like oh god But the thing I mean, but it's it's a little bit dangerous to talk about that stuff though because Then sometimes people get the idea that we really are just kind of sitting around making stuff up, you know Like and so then people think like oh, I can be a cosmologist Like what if the universe is shaped like a football, you know, and I think that that the the sort of Disconnect there is that like the ideas themselves if they're not backed up by the data or by like a very rigorous model are really not that important like once we have

Data and we have some kind of Unifying theory that says that this is probably the way things are then it's like super cool, right? but If somebody had said like oh, you know, maybe the universe is like this Like we don't really know what to do with that and it doesn't it's not really helpful and you can't just spit ball like yeah, yeah, yeah, exactly like like you have to it has to be connected to something we can test or or Write down mathematically or else it just it's kind of not helpful Which is you know, it's a bummer

But but once you do have the sort of mathematical tools and stuff and you can speak that language, you know Then you can get really creative and then you can just do really fun things So like I have an ex I have a project. I'm working on that has to do with Have a few interesting projects actually So I have one So here's one that that could be fun So okay has to do with black holes and galaxies and the bending of space. Okay, so So every time there's a massive object it bends space around it

And so that means that light when it goes past bends around So like a lens like the massive object acts like a lens for light and so light gets bent around So there's this way to study like what galaxies are made of by having a very bright light behind the galaxy like really far away and Looking at how that light like bends around Inside that galaxy and like how the light fluctuates as things move and stuff like that And that's called gravitational microlensing in this case the kind of thing I'm working on but the details aren't important but it's it's

it's this thing where Like the thing that's making the bright light is also a black hole Because it turns out when you have a supermassive black hole like billions of times as massive as the Sun those things can be pulling matter into themselves and that matter lights up like a whirlpool of Stuff what and it can make this incredibly bright light that you can see like across the universe and So so we use that as like a backlight To study the stuff in a more nearby galaxy to find out how many black holes there are in that galaxy So black holes make light sometimes. Yeah supposed to be confusing. Yeah, it's like I think I mean

I think it's like it's one of these things It's like the biggest misconception about black holes is that they're dark usually they're not like the ones We know about are usually not dark and it's it's yeah, it's because they're not it's it's because like technically the black hole itself Can't be seen but it's doing so much that it like affects everything around it and so Usually you can see black holes because they're like really destructive and like the stuff is falling into them kind of like if you If you had a drain at the bottom of a bathtub, uh-huh Like you might not be able to see the drain through like the you know bubbles or something

But you can see that there's like a whirlpool of stuff falling in at that point Oh, man, and that's how we see black holes in space Usually is we see that they're they're pulling in a lot of matter and so they let that matter lights up And so once it goes into the black hole, we can't see it But it spends a lot of time whirling around really fast. It's like an intergalactic Garbage disposal. Yeah. Yeah. Yeah, and it can be it's some of the brightest things in the universe are black holes We call them quasars when they're when they're the supermassive ones and they're pulling matter in like that and and

We have so so that's like those are for black holes that are like millions or billions of times as massive as the Sun and How far away are those puppies? All right. Well Okay, supermassive black holes the one is the ones I was just talking about millions or billions of times the mass of the Sun Those seem to exist at the centers of pretty much every reasonably sized galaxy we know about at the centers Yes, so including ours. Yes. Really? Yes, so our galaxy. Okay quick note Let's do a few cosmological basics our galaxy is Mokue, right and this next analogy I got right off of NASA's night sky website, which I think is for children, but it's so helpful So, okay, imagine our Sun. It's one star among hundreds of billions of stars in our Milky Way

Right, so if we shrink the Sun down to smaller than a grain of sand our little solar system Venus Mercury Earth All of those would be small enough to fit the whole solar system in the palm of your hand now on that scale with our solar system In your hand the Milky Way galaxy would be the size of North America and the Milky Way is big But our next-door neighbor and drama galaxy. It's about twice as big as the Milky Way scale is important here I suppose but at the center of our galaxy. There's a black hole So the Milky Way is like a disc of stars and gas and dust and stuff and we're sort of out toward an edge and At the center there's a bulge of stars and gas and dust and then in the middle of that

There's a black hole. It's four million times as massive as the Sun. I didn't know that do we have a name for it? Yeah, yeah, we have a name for it. We call it Sagittarius a star. Okay, which is a silly name It's because it's a kind of I think it was like think a radio source and because it was Pulling in some matter and so it was lighting up in the radio a little bit And so ours is not pulling in very much matter at all. Okay very occasionally It'll eat a little blob of gas and the astronomers get super excited but like there's very little happening with it, but it does it is really big and

It's got a bunch of stars orbiting really closely around it And so you can actually go online and see like data Follow like tracing out the paths of some of these stars and you can see them like whip around as they go really close to the Black hole in their orbit So some of them have these orbits that they're really far away And then they come in really close and they go boom like that right around the black hole And so you can figure out exactly like how big it is and where it is by watching these stars go around it really quickly So I did a little looking and if you Google

European Southern Observatory and s as in Sam to you'll find this. Oh my god like a rimshot in a basketball game like yeah Yeah, yeah, like that except it comes back around and that's on an orbit. So yeah, so there's stuff Orbiting really close to that black hole that one is like well, let's see. It's 8,000 parsecs away. I don't know how much that is in light years A parsec is about three something light years. So light year is how far how far take how far light travels in a year, right? So light moves very quickly. So that's a very long way So for example light travels It takes like eight minutes to get between the Sun and us

There's a rule of thumb actually if you want to know how far how fast light speed is it goes about a foot per nanosecond a Foot per nanosecond. Yes. Oh, that's easy to calculate. Yeah, just a bunch of zeros, right? Yeah, put a zero on it Yeah, that's easy. I know but it's kind of cool because then you can like you can say like if somebody is like ten feet away from you They are ten nanoseconds in the past They're ten nanoseconds in the past. Yeah. Oh, man. I'm gonna trip out Like we're like three nanoseconds apart right now Weird It's great though and I I learned this recently and I've already forgotten it which is embarrassing the distance

Between us and the Sun is a certain. What is the you? Oh, that's an astronomical unit Astronomical unit. Yeah, that's the distance between us and the Sun I just learned that and then completely forgot it all in the span of a couple of weeks Okay, there's no reason to know that stuff I want to know a little bit more about when you were a kid by the time Katie was about ten years old She was inspired to pursue some form of cosmology and she was already a fan of British cosmologist and Theoretical physicist Stephen Hawking. She was already hip to him. She's like, I know this dude Now if you need a quick brush up on him as a person after this podcast watch the

2014 Eddie Redmayne film the theory of everything Cosmologist what's that? I study the marriage of space and time perfect couple Or you can just watch the trailer and start crying Like somebody you know Now if thinking about living on a dust moat floating in a sunbeam wasn't inspiration to do what you want to do in life Consider a human who's figuring out the mysteries of the cosmos doing computations and cracking theories About which I can't even comprehend the first paragraph of the Wikipedia page

Also while living with ALS Katie is one of several billion people Inspired by Stephen Hawking. What was it that Stephen Hawking did or or what did you how did you become aware of him? And how did you kind of absorb what he did? Oh, I'm not sure how I became aware of him I think the you know He was on TV every once in a while and I had a brief history of time the book and I read that And I just like I don't know like I was interested in black holes And I was interested in like the Big Bang the Big Bang theory being that the universe began those 13 odd billion years ago With high temperatures and high density and it's continued to expand

also note if you Google Big Bang theory all Roads lead to Sheldon. So just Bikash call it Big Bang as far as Wikipedia is concerned And so I would read about that stuff and Stephen Hawking was a big figure in those those areas and he was he was doing a lot of science communication and He would he would visit Caltech every once in a while And I was growing up in LA and Sir Long Beach And so I would sometimes like my mom would take me to see talks by by Physicists because I was super excited about these things and so I remember seeing talked by him

I remember seeing a talk by Paul Davies and like, you know Just prominent Theorists would give talks sometimes and somehow my mom would find out about them and take me along Because she's she's really into science and science fiction and physics and everything Have you gotten to meet have you gotten to meet Stephen Hawking? Yeah Yeah, so when I was at Cambridge So I spent a year at Cambridge during grad school Just kind of visiting and working with people on some research and I was mostly based in his department and my office was like directly below his yeah

And we were in the same like research group Basically, I mean like like we didn't talked like we weren't I wasn't in his research group But we're in the same is the Center for Theoretical Cosmology and like we're both based there So there were you know half a dozen professors who were involved with that. He was one of them and I was a grad student visiting and So I would go to all these like, you know meetings and the coffee and stuff and Shortly after I was Shortly after I started this being a visitor there

somebody asked me to do one of the Like lunch seminars So basically if you're a physicist and you're visiting another department, you're kind of obligated to give a talk That's kind of how it works So they say hey, can you give a talk? She's like, yeah, I'll give a talk for the Thursday lunch seminar So she does it and it turns out that it was the lunch seminar that like Hawking goes to I'm getting ready to give the talk and I see like several of my professors in the audience like looking expectantly at me

This one I'm like freaking out, but he but he wasn't there Hawking wasn't there. So I was like, it's fine. It's fine. And I'm getting ready to give the talk and then I hear this like Oh my god, my stomach is cramping just hearing this and he shows up. Oh get so much worse. Oh God, um, so I've told this story before but it's it's still it's still like is it makes me like sweat So so I was I was getting ready to give the talk So I start the talk like I put up the title slide and I was the tie the topic was primordial black holes Which is a concept that Hawking came up with along with some other people And yeah

And as I'm starting like as I after I introduced the title and stuff I hear this this voice say thank you and it was his voice and I was like And everybody kind of laughed, you know, and I thought maybe he was like thanking me for talking about the thing that he invented, you know, but I don't know and you can't ask him to elaborate because he His speech is very like slow. So he uses this machine thing and it just it's very slow Um, it tracks his eye movements. Uh, yeah, okay. Well, no, not exactly. It tracks There's a little sensor that looks at his cheek Okay, and so he kind of winks and that like selects words on this like list and it takes a couple minutes per word sometimes

Right, so you weren't like I couldn't be like yeah, yeah So I had so so I just kept going and then eventually like I heard it again Yes, or later on no or I don't know or just random things as I'm going and every time like I'd look at him I'd be like, you know, but he would just kind of look blankly at me and the person who was like taking care of him This is a lunch seminar So the person who was taking care of him was like feeding him and she just kind of looked blankly at me and like I had no idea what was going on and so I would just kind of pause and Then continue

Was he heckling you? What was happening here? I had no idea and I was so nervous and like all the professors were there and and already one of the other Professors had been like asking a whole bunch of really tough questions on like the second slide So I was already like freaked out just imagine being in this situation. It's a nightmare It's like the best Nightmare ever but like I answered the questions and he seemed to be okay with it So I finished the talk and Hawking laughed and he hadn't asked any questions and I Asked one of the seminar organizers like what what was that and he was like, oh, well when he eats

The machine oh my god one is chewing and it just picks random stuff from like the quick select menu It was just like here's the you know, here's the most common phrase is yes. No, maybe I don't know I don't think so. Oh My god, this is like the worst deodorant ad ever like this is the most stressful situation You could possibly ever have killed me. Oh my god, and like they could have told me. Yeah, they could have given you This happens every time. Oh my god. They just think I like they just didn't mention it Any word on whether or not he liked your talk? I have no idea. Oh my god Did you ever tell him that you went into cosmology because of him?

I I don't well So the first time I met him when I was 16 oh just 14 14 baby baby I did tell him then that I was a big fan. So Hawking was at Caltech and Candy got her mom to drive her and a friend there to hear him speak and afterward They were walking the same way that he was going when they were leaving and she was too nervous to say hi My friend went up to him and said my friend would like to speak to you She had a wingman

So I went up and said that I was a big fan and I enjoyed his work and I thanked him and he said thank you very much Now what happens to you when you get that because you're really I mean I'm not gonna fangirl right here I'll do it in the intro, but you're like a very big voice in science communication. You're like You're a very well-known Astrophysicist cosmologist. What can what how do you feel when people come up to you and say I was inspired to study this or you've Changed my course like what kind of reactions do you get? It's I mean it doesn't so it's not I'm not like Stephen Hawking Like I'm not that level of famous and I'm not that level of like important in physics and stuff and and you know So it's it's kind of a different thing, but I do you know sometimes people do like tell me that that they

Like so one of the messages I've gotten a couple of times is a like a teenage girl will say that She Didn't think she could do astrophysics But she really loved it and then she saw what I was saying on Twitter or something or she saw me speak and Then she decided she was gonna go for it. Wow. So I do get that sometimes and I Like my feelings don't know what to do with that But it's really it's really sweet and from a black hole I mean it is really sweet

It's really like Rewarding when that happens and and it it makes me feel like maybe like the stuff is Maybe the stuff I'm doing is is worthwhile when people say stuff like that or like a little kid will sometimes say that they want to Be an astrophysicist or something and they'll be really excited to meet me like I was I was in Raleigh a couple weeks ago and I was I Was sitting in a cafe and I was wearing my NASA jacket with the little NASA badge on it that I got it JPL JPL by the way is NASA's Jet Propulsion Laboratory and it's nestled in the Golden Hills of Pasadena, California

And it's responsible for things like rovers on Mars and according to press materials JPL's function is to engineer and fabricate Cool-ass shit. That's like so dope. That's very bold NASA Also, do not fact check that part. It is not true and this little girl came up to me and she was probably like eight or something and She asked me if I work for NASA and I said I don't work for NASA, but I am an astrophysicist and And so we'd like talk a little bit and she said that she really is into space and stuff And I was like well

I'm giving a talk at the museum in a couple of days you can come and hear my talk and so she and her mom came to my talk and She asked a question and it was just really sweet and I was like. Oh, what was your question? Um, I think her I think her question was about like what's inside a black hole Mm-hmm, which is a good question. You're like a bunch of space garbage. Well. Yeah, so it's I mean That's it's not a straightforward answer really because once stuff goes inside the black hole It has to go straight to the singularity and I can't do anything else And so then it doesn't really exist at that point like that's kind of subtle But anyways a good question and apparently like she was talking about the talk later on and I was like

Inspired somebody she's gonna be in your department later and give her a talk for your lunch Dumb questions explain the singularity. Oh, yeah. Yeah, so a singularity is So it comes up in the context of the Big Bang and in the context of a black hole Mm-hmm a singularity is like a point of infinite density, okay Usually in physics when you have a singularity, I mean a singularity basically means it's a point where something infinite happens We're like where things diverge in some way And usually when that happens in physics, it means you've done something wrong

Okay, and it's a sign that the theory is broken and you just can't deal with that because there's none of the None of the theory like really works at a point of infinite anything. Okay In the black hole like the way that black holes are defined and the way that we understand how the gravity works there really should be a singularity at the center of the black hole and Everything has to move toward it. So so the you know, the black hole has this is this thing that like the way you make a black hole I'm gonna get back up. Yeah, no backup because I'm like where they come from. What's the deal? Yeah, so the way you make a black hole is you take a really massive star and you wait a while millions of years and the star will explode and

The core of the star will collapse on itself and if it's massive enough then I mean the reason that the star didn't collapse before Is because it had nuclear burning happening and it was kind of keeping it puffed up Okay, right and so you had this energy source that's sort of pushing against it Kind of like if you have like a balloon and the air inside is pushing the the rubber out, right When the star explodes, there's nothing to keep it from collapsing under its own gravity The you know, you you get to a point where there's you can't do any more nuclear fusion So nuclear fusion is when atoms join to become a different kind of atom

And they give off energy in the process like two hydrogens becoming a helium and giving off energy Now this happens with atoms up to the size of iron at which point that fusion starts to take energy You can't get any more energy out of those processes because you've gotten to a point where you've just the whole Center of the star is is iron basically and it can't go farther than that And so then you have this like huge chunk of iron that's not being held up by anything And so it starts to collapse under its own gravity like that stuff just falls in and it has to go toward the center And it has to keep going toward the center and it can't go any other direction And so you end up with the singularity this point of infinite density technically

What is the shape like is it like an ice cream cone that has an infinite tail or what? I mean you can visualize it that way if you think about it in terms of like a 2d analog like usually when we think of space-time like the pictures are always like a big rubber rubber sheet The rubber sheet visual is so helpful for comprehending space-time But also when I think of rubber sheets usually the situation is not Comfortable it's either like an awkward grade school slumber party Explanation or some suburban dungeon kink that sounds Exasperating at best, but for space

rubber sheets Thumbs up and you have this big rubber sheet and you put a bowling ball in one spot and that bends Around and so then when you take your tennis ball and you try and roll it past the bowling ball It makes a little orbit and falls in right. This is the usual visualization for space-time But that doesn't have the right number of dimensions because space is space is three-dimensional And then you can think of time as another dimension, but that's kind of separate thing I am curious about time is a fourth dimension. Okay. We can talk about that. Okay. I'm sorry I have so many questions, but anyway, so if you if space is three-dimensional then the way gravity

Like works on it is that it kind of like pulls space inward toward itself So like a massive thing kind of pulls space inward toward itself So in the context of a black hole it would be like a place where space gets really scrunched up Right, but it's easier to think about it in the two-dimensional case So it would be like you have your rubber sheet and you you pinch a piece of that rubber sheet And you just pull it down and you just keep pulling it down And it just goes to a point and it's like, you know forever and it gets deeper and and narrower or whatever, right? So you can think about it like that

But then you think about like a three-dimensional analog and your brain kind of breaks and it's right But yeah, so it's basically a place where space is really super curved. Okay, really super bent inward and So there's a point So if you think again about the 2d kind of thing the rubber sheet You can you can still move past like if you if you have your your like little hole that you've pulled down on your rubber sheet You can still take your tennis ball and roll it past that and it'll keep going But if it gets too close it'll fall in and there's nothing you can do about it And it'll always go toward the the deepest point and so that's like there's this horizon this this distance from this from that singularity

Where if you get closer than that you will fall in no matter what and you will just keep going and you can't ever escape And light itself will fall in too because light follows the curve of space And so if space is curved enough then light will just follow that curve all the way down Oh, man So once you know, so you throw throw a flashlight into a black hole like that light never comes out again It just keeps it goes that that light beam no matter which direction the flashlight is facing the light beam will bend toward the center And what is that danger zone called? The event horizon. Okay, that is the event horizon. Yeah, that's the event horizon

I mean you should probably stay farther than the event horizon in general Um Because other bad things can happen to you if you get close to the black hole if you listen to ology's episode one vulcanology and thought jumping into a volcano was intense like hang on to your butts right now I mean So for one thing the most of the most of the ones that we've seen directly with light are Pulling in matter, right? And so that means that there's a lot of hot stuff

falling into the black hole in a form of a disc And um, so that'll radiate you to death If you get too close and then if you if you get close If it's a small enough black hole then when you get close the tidal forces will kill you So tidal force is where you have like it's where you have more more The gravity is pulling stronger on part of you than another part. Oh, so like if like if you imagine, you know You're falling feet first toward a black hole The gravity goes the strength of the gravity goes up so steeply because it's such a compact

Steep thing then your feet will be pulled on much more tightly than your head and you'll be stretched out And it's it's there's a word for it. It's called spaghettification It's actually called that Yeah, yeah, so so you have to watch out for spaghettification if you get too close to black hole Who the hell named that? I don't know. I don't know. I mean hawking uses it. I don't maybe he came up with it I'm not really sure. Oh my god of all of the things to call it. Yeah Of all of the things like turns you to spaghetti. I don't know like that's just what else you're gonna call it like Oh, I mean it's it's tidal disruption, but I love it the most

yeah Spaghettification was indeed coined by hawking in his book a brief history of time and If you happen to google image search this you will find a bounty of photoshopped images of astronauts being tapered into space noodles by cosmic forces I'm so impressed By this astrophysical whimsy. Yeah, there are a lot of there are a lot of really silly names in in astronomy Who gets to name this stuff? Uh, whoever comes up with it

I mean people who come up with the name it but like sometimes the community names it like the big bang That that was a joke It was the word was a joke the term the big bang like somebody came up with the idea that you know The universe started small and has been expanding And somebody was like oh the big bang And that It stuck. No. It was a throwaway. Yeah. It was like it was mocking. Did that person get pissed that it stuck? Um, I'm not sure. Okay. So english astronomer fred hoyle coined the term

Big bang it was during a radio broadcast in the late 1940s, and it was kind of an accident Now the story is he's so bent that it stuck but apparently he denies that so drama In terms of what in terms of what your output is you're you're a professor you give talks you travel all over the world Like what is your big goal as a cosmologist? Like do you want to write an encyclopedia about cosmology like what's your what's your end game? So I'm I'm almost a professor. You are I'm I'm gonna be a professor Well, I'm gonna be an assistant professor starting january 1st. Yay. Yeah, okay

So I'm not quite a professor yet So in a matter of days pretty much katie will be assistant professor of physics at north carolina state university So tweeted her and say congrats. So what are my goal? Uh, I mean I want to figure stuff out, but I don't have like there's not like one thing where it's like I must solve this problem. I I kind of like Just working on whatever fun stuff comes up, which is not what you're supposed to do But it's what you like. It's what I like. I mean, so the big thing I'm working on right now has to do with dark matter so dark matter is this invisible stuff, you know

Um And it's possible that dark matter has this weird property where if you take a dark matter particle and another dark matter particle and you You like collide them into each other in just the right way They'll annihilate and create other kinds of particles. What so that's a possibility Um, and if that's the case if that's a thing that happens Then it can mess with how the first stars and galaxies form because those form in things like blobs of dark matter And the formation of those is kind of delicate Because you have to get the right balance of the gravity and the gas and all this stuff

So if dark matter is going and like annihilating all the time then that Sort of messes with that balance. Huh, and so it can change the way the first stars and galaxies form and then we can look for Evidence of that with telescopes So this is the kind of problem that I like where you have like a sort of Fundamental particle physics problem and then you try and figure out how to look for it with telescopes So what is your work involved? Do you have like a moleskin that's just filled with like gobbledygook equations? Or are you working on a computer with data sets like where when you're like when you get down to work? Yeah, what does that look like? So I do have my moleskin with the fill of equations over there

I brought it with me So I have that I also have a whole bunch of code that I've written to try to solve some of these equations that are in the moleskin I mean, so the so the usual thing is like, okay You talk to people who work on similar things and you Try and come up with like what is it? What is how can we answer this question or what is a question we can answer with this observation? Or like what would be a cool thing that might happen that we could find out if it does happen

so then physicists talk to each other and write stuff down and look at papers and write down more equations And I was kind of surprised to realize how collaborative this could be I always imagine physicists needed to be like sequestered in a well-appointed lab Or a classy den to just think clearly, but no, there's like a lot of chatting happening and then once you figure out like what equations you need to solve and What things you need to calculate then you then you go to the computer and you write code to calculate those things and to put out numbers and draw graphs

And then you see if you have something interesting or not See if it all kind of clicks. Yeah. Yeah, and you see if like, you know Does this tell us that this is going to be an interesting technique to test the theory or not? And then depending on you know, because this is all theoretical work sometimes Sometimes you find well, this is just really uninteresting and nobody's going to care. So I'm not going to write it up Sometimes you're like, well, you know, it turns out you can't measure this thing with this technique But we should write that down anyway because people might have tried otherwise And then sometimes it's like, oh, we we can measure this thing with this thing

And that that'll be a really interesting result and we'll get a better answer than anybody's gotten before So we're going to write it up and be really happy about it And then you go toward writing it up and publishing it. Yeah Yeah, and then you write the paper and then you publish the paper and then you know Or you send it to the journal and the journals the editors or the referees are like, you know You should do this differently and so you do that differently and then eventually it gets published What is the craziest paper that you've ever had published when the title of the craziest paper? Because just looking at paper titles is so funny to me because they're so specific and wonderful

I mean, I guess it depends on what you mean. I wrote a paper Called known unknowns of dark matter annihilation over cosmic time That sounds like the best like Norwegian metal album ever It was like, well, yeah So that was all about like what we know. We don't know about this problem. Mm-hmm. I've calculated a bunch of stuff. Um I've I had some papers about Like axions and and those are theoretical particles that are super cool Is there an upper limit to how many words your paper title can be?

Yeah, you don't want it. I mean, you kind of wanted to be punchy, right? Like like the whole known unknowns thing is I wanted it to be like eye catching, right? It's good marketing. Yeah. Yeah. So you got to think about marketing to some degree And you don't want it to be a long title because people are going to be skimming it. This part is crazy It's like trying to buy Beyonce tickets. So the way that people find papers to read is every day every weekday the website It's arxiv.org. There's like 100 new papers about astronomy and physics and math and stuff So so the way that people find papers to read Is every day every single day

Every weekday the archive website It's arxiv is how it's spelled, but we call it the archive the archive website displays like 100 papers New papers about astronomy And there's just a list and the titles. So there's the titles and the authors and maybe like the abstract depending on how you read the archive and If you're a responsible astronomer

Then every morning you Wake up and you read the archive and you skim the papers and the and the abstracts and you see which ones are relevant to your work And then you you know open those and read, you know skim those papers and find out if like They tell you something interesting you get information. This is how you keep up with the field. That's so much work. It's so much work It's like a lot of work And if you're somebody who maybe does you know particle theory stuff as well Then there's a whole other archive for like particle theory and then particle phenomenology, which is more like the Phenomenology is like where you try and figure out what you would see in this in the universe

That's closer to what I do So then if I if you're trying to read particle theory and phenomenology and astronomy You can get like 150 papers or something every day. It's a black hole. It's just it's impossible to keep up Oh my god But anyway, so because of that you want your paper title to be punchy and eye-catching But the other thing so there's a this This is like so totally inside baseball, but there's there's This ridiculous thing that happens

So the order of the papers as they appear on the website is determined Just by what time they were sent in and after not too long These are literal geniuses. They were like duh. There's a cutoff Time of like 4 p.m. And sometimes on I don't remember which one Where if you get your paper in as close as possible after that time it will appear at the top of the archive And so there's this you can people have written papers about like the spike in submission times Or like everybody's trying to get like four, you know a clock zero zero one second Like they all want to get it like exactly at that moment

So that their paper will be on the top of the list because a lot of people you know Like they open the archive and then they just get like exhausted by the time they've gone through five papers And so they don't get to the end of the list and so There's this ridiculous like This ridiculous ritual of when you're when you submit your paper to the archive You're trying like you watch the clock and you try and hit the submit button at exactly the right moment That makes me so anxious. It's like when some when people comment first on my youtube video It should be randomized because there's really it's also been shown that it does matter in terms of like citations

That's not right. It's not right. Oh my god Yeah, um, oh wait, what was the question that I had right on top of that? It was it was definitely a dem one It was definitely a stupid question. Um, I don't think any questions are stupid. Are you sure? I think these are good questions. These are important questions because like what it doesn't Like, you know, these are like if you're asking questions about something because you're not an expert in that field Like you can't be an expert in every field if I ask questions about entomology. I'm gonna have no idea what's going on Okay, that makes me feel better. I'm like, I'm still trying to remember what the difference is between a bug and not a bug, right? Like I don't know

I'll give you some clearance on that. Okay, but the problem is is you study the universe. Yes, so Could your field be any broader? Like no, no, it could not literally everything Yeah, and this this can be a problem too. Like when I give talks I have to be prepared For anything And that used to freak me out a lot and now I just feel like like I just have to I have to read as widely as possible and sometimes I'll be like, I have no idea

but like like I gave the talk about gravitational waves at in rally the other week and one of the questions was uh, tell me about the great red spot on jupiter and I was like It's a storm it's been shrinking Uh, there's a There's a spacecraft looking at it. You should maybe talk to somebody who studies Studies about that the great red spot. By the way, that's its actual name. It's a little on the nose Also, people mix it up sometimes with the great dark spot, which was near jupiter's northern pole So y'all call me let me name some of these things also

How did katie feel about the detection of gravitational waves? This was the ligo project you may have heard about in 2016 The detection of gravitational waves by the ligo instrument um Was probably the biggest discovery in physics in my lifetime Damn. Yeah, that's a big deal. It's a super big deal. Um, I Win that announcement. So the first the first detection was last year sometime Well, the detection was the end of 2015 and it was announced. I guess um during 2016 um

The the announcement was in I don't remember what time zone it was or whatever But it was such that it was going to be 2 a.m. Local time in melbourne. Mm-hmm. And so a bunch of us Got together and like had a party Yes In in a university department like we brought food and booze and like we watched videos and like we took like We took selfies. It was really late But we were just like we got to see this live, you know And and there were there were two people in the room who who were part of the collaboration

So they they already knew what was going to be done But the rest of us like we'd heard rumors, but we didn't know for sure what was what that was going to be announced And yeah, it was it was just a huge party and it was a we were really excited and like we just Everybody was like clapping and stuff when it happened. And I mean it was it was a huge deal the way that it was announced was like A press conference from like an awesome 80s movie. Yeah ladies and gentlemen We have detected gravitational waves we did it I mean how cute is that so that was dave right see he's a laser physicist and he's director of the lego lab

And I love that audio So much. It's just like pure triumph like the last scene of A schwarzenegger movie or something we have detected Gravitational waves Yeah, yeah, no, I remember that very clearly So explain to me why the detection of gravitational waves is such a big deal Okay, so so first gravitational waves are

Are ripples in this fabric of spacetime? So, you know the space space can be bent around massive objects And when massive objects are moving through space if they're moving in an accelerated way Which could be in an orbit an orbit as a kind of accelerated motion That creates ripples in in this sort of spacetime fabric Which is kind of hard to visualize and explain but it ripples through space and so like when you have Really massive objects moving really quickly

That can make large disturbances relative to other things. I mean if I wave my hands I'm making gravitational waves, but like that's not detectable so so So two black holes orbiting each other Make really big detectable gravitational waves, especially when they get so close that they're about to merge into one thing So you can have two black holes in a binary orbit orbiting each other And then as they get closer and closer the signal gets stronger and stronger You know the waves get stronger and stronger and then they merge and that makes this big sort of burst

of gravitational waves and The way that gravitational waves Work, they're not like ripples on a pond usually when you see a visualization. It's like ripples on a pond But that's that two-dimensional analog, you know again um And they're not like if you were if you're standing there the gravitational wave Like moves your space that you're in but it doesn't just like move you up and down what it does

Is it stretches and squeezes the space that you're in? So let's say that you're standing there and a gravitational wave comes and hits you in the face What that does to you is it stretches your space a little bit So you get a little bit taller and at the same time a little skinnier and then a little bit shorter and a little wider What and like it oscillates back and forth? So as the waves are coming at you each wave is giving you that like that stretch and squeeze stretch and squeeze What and so it's actually distorting your shape. Oh my god when this is happening This is like a big boy owing and it's it keep like

For everything that creates gravitational waves is this doing this to us all the time micro micro basis Yeah, yeah, so so the ligo experiment is built to detect these things They have two detectors and each detector is like It's an L shaped thing Each arm is four kilometers long now if you've seen photos of this you might think from a distance is some shit that we built Like on mars because there's just this treeless Ochre landscape in the desert. It seems to look lonely in every direction But no, it's just washington state and they shoot lasers

Back and forth along these two arms there They meet at the center and and they're measuring the lasers are just there to measure the length of those arms basically Um, and when a gravitational wave comes and hits That detector it makes one of the arms a little longer while the other one gets a little shorter and vice versa Depending on the direction and the you know phase and everything So if it if it does that then the detector can detect that the length of the arms has changed And and then that's the signal is the changing of the length of the arms And the level on which that happens. So this is four kilometers, right? Yeah, that's about

Two and a half miles america the first detection When it was detected the the length of that four kilometer arm Changed in length by a thousandth the width of a proton Oh my god. Yeah, that's a teensy tiny. That's really small and this was A huge collision. Yeah. Yeah, this was like it was 1.3 billion light years away. So it was very far But it was like the black holes were around 30 times as massive as sun And they collided and So it was a pretty strong signal like it was a surprisingly strong signal like if you actually looked at the data

Raw data like you could see it which is not usually the case in in this kind of field Usually like you have to do lots of processing but like you could see the the signal is very strong So but yeah thousands the width of a proton So the you know, your own height is changing much less than that, right? Because you're about four kilometers long Sure I'm so I'm getting a little bit not quite as tall and not quite as skinny and not quite as short as fat is Yeah, not noticeable in a photograph say yes. Yeah. Yeah. It's really it's a really subtle effect. Um, but But yeah, so so that's the gravitational wave. It's the detection of that that

Change in length that sort of stretching and squeezing of spacetime and each time the black holes You know black holes or or something collide You get this kind of like the the wiggles will come faster and closer together And so the frequency of this changing of shape is going up and the amplitude is going up And so it makes this kind of rising sound if you transmit it if you change it into sound It's like a sort of like And the like end part is when they collide um, and the reason people

Change it to sound a lot is because the frequency of these waves coming like how how quickly the stretching and squeezing happens Is about the same frequency as like sound waves Okay, so it is kind of audible like if you change it to sound it's kind of audible And that was like the the boop heard around the world, right? Yeah. Yeah, it's called a chirp a chirp. Yes Just a little chirp chirp Okay, you ready for this? This is the sound of history So what does that mean Going forward for astrophysicists. Yeah, and like how many more have we heard since then?

So there have been oh gosh, I didn't even know the number like something like five seen now And the most recent most recent one was was two black holes But the one before that was the neutrons there was two neutron stars And those were a big deal because Those when they collided also created a gamma ray burst a gamma ray burst Super energetic explosion So we can't see gamma rays, but they pack a punch and a burst

And so we were able to see the collision from the the gravitational waves, but also from light And that was a huge deal and I can talk about that for hours but It's it's a big deal the the whole thing is a big deal for a bunch of reasons one is that this Like the existence of gravitational waves was kind of known indirectly because we'd seen systems where like you had two Two uh pulsars orbiting each other so pulsar is a kind of neutron star a neutron star is like the core of a dead star It's so we'd we'd seen things orbiting each other where the the changing of the orbit

Could only really be easily explained by Gravitational waves kind of radiating energy away from the orbit and so the orbit got smaller because gravitational waves were pulling energy away And so shrinking that orbit so We had indirect evidence the gravitational waves existed, but we'd never seen them directly And seeing like directly like detecting like feeling the gravitational wave is a huge deal Right and the in gravitational waves were like the last the the last prediction of einstein's relativity to be confirmed Einstein's theory of relativity remember our perception of the force of gravity is a bendy spacetime thing

I'm very paraphrasing a lot So he predicted them 500 100 years About 100 years before the first detection was made So it was it took a long time right to see these things but so it was confirmed that and it's just this incredible laboratory for for relativity for physics because By detecting the gravitational waves

And looking at the signal we were able to determine that gravitational waves travel at the speed of light We didn't know for sure before that was part of the theory, but we didn't know for sure So we we figured that out It told us stuff about how black holes are made like what black holes are made of sort of like the properties of black holes By examining very closely how they come together and merge How much energy the gravitational wave bursts creates, you know A lot of stuff about about that and then because now we can we can watch black holes colliding

In the distant universe we can learn about how black holes grow, you know By when they collide with each other and that tells us something about how black holes grow It tells us something about how galaxies grow It tells us something about how stars form because black holes are the end results of stars When you were a kid were you ever hoping that this that we would be able to detect gravitational waves? Um, were you like I've been waiting since I was a little girl um So so I didn't know a whole lot about gravitational waves when I was a little kid, but there was there was a really

beautiful moment During one of the the detection of the neutron star collisions when one of the scientists was he was He was talking about the neutron star collision and the neutron stars when they collide they make a slightly different kind of like chirp sound Okay, here's the sound of the neutron stars booping themselves together So the the black hole one is actually a lot quicker than what I said, but the neutron star one goes like It takes it takes a while and it does it and so And there had been simulations of this for years I mean the scientists who was talking about the discovery said that he had been waiting

To hear that sound from nature for 20 years and he just did Um, and it was really touching. I mean so for me, I I knew about LIGO because it was um It was partly um headed by people at caltech and I was an undergrad at caltech And so when I was an undergrad there, um people were talking about a lot and there was There was a famous bet between Like kipthorn and steven hawking or something kipthorn, by the way is a theoretical physicist the 2017 noble laureate About whether or not gravitational waves would be detected by the year 2000. Um, I started caltech in 99 So they were not detected by the year 2000. So that bet was lost

Um, but it was a funny thing because when I first got to caltech They were building LIGO and it was this big deal and everybody's like we're gonna detect gravitational waves. It's gonna be amazing And then um, you know, and LIGO was being built and I was like, oh, it's any minute now And then I I left caltech and I went to grad school and then after a while I was like I haven't heard anything about this for a while, you know, and I realized that like They kind they'd kind of like they'd been like, yeah, we're gonna detect your gravitational waves And then they kind of got quiet for a while and I found out later on asked about and they were like, oh, no It's advanced LIGO is so there are some upgrades of the years from initial LIGO to enhanced LIGO

to advanced LIGO It's kind of like the the tall grande inventi gravitational wave detectors Just maybe need a little more to get the job done really gonna do the detection Initial LIGO was like, maybe it would get lucky, but advanced LIGO really see something. I'm like, really? So like for a while I was like, I don't know what I feel like I don't know if I believe that this is really gonna happen But then, you know, as soon as they turned advanced LIGO on like Within like a week or something they they saw this thing. So that's like they really they really did it

And it's the most like it's the most precise instrument ever built by humans. Um, I think I read that somewhere It's like the the I mean you're measuring something So tiny it's crazy. It's it's impossible. I use it's incredible how like what went into it in terms of the engineering and You know just the the physics and like they had to they had to Correct for things like the like how much the photons hitting the mirrors would move them. Oh my god. Oh my god That's a big part of the the noise in the signal That's called the photon shot noise. They have to deal with that. Yeah. So stuff like that

I mean, it's it's incredible that they were able to do this. So can you get the chirp as a ringtone? I believe you can you can I believe so. Yes Would you get the the neutron whoop or would you get the well the black hole one the the black hole one You have to speed it up to make it sound cool. Um, so you can still hear it, but it's more like a Like so so in the actual data, it's like That that's kind of what it sounds like but then when you when you speed it up it goes whoop whoop But it's very quick. Whereas the neutron star one. It's like I feel like yeah, I feel like that's the way to go. Yeah, yeah

Let's say someone is interesting cosmology, but doesn't know a lot about it and is intimidated by it What is the best book to pick up? I actually and this is I don't know if you've ever read this But I was I was in Thailand and I was staying in a hut and there were some there was a free book pile Oh, yeah, and I picked up a book called quantum mechanics can't hurt you This book was actually called quantum theory cannot hurt you. It's by marcus chone and it's delightful I found my copy. It's still moldy from a monsoon. It was good. It was very it was very layperson's terms but um, I clearly don't didn't retain any of it, but

Is there a book or a documentary or something? That's just a good primer because like in this episode There's no way to describe everything, but like what's a good go-to like Astrophysics for dummies. What are we talking here? Is there a pamphlet? Uh, so I I wish I had a really good answer for this That makes me feel like you don't You're wincing the thing that so the thing is like I don't I don't read a lot of popular level stuff and

There's a couple of reasons for that So number one She doesn't have much time to read non papers because there's like a billion papers And when she does she likes to read about spaceships. Okay, two when something is written for the general public Astrophysicists have to take that lay information and kind of back translate it To a more technical version in their head So it's like if you're a bartender and someone writes she drank a whiskey, but you're distracted wondering A whiskey. Well, is it like a bourbon? Is this a single malt scotch? Was it a rye?

Tennessee whiskey. Is this on the rocks? Was it a cocktail? There's so much detail in it I mean Sean Carroll has written several books that are really good. Um, so take a look at those Um, there's a physicist Katie freeze Catherine freeze who's a dark matter Uh theorist like me. Oh, uh, she's a dark matter cosmologist and she's written a book called uh cosmic cocktail And it's all about um about dark matter and also like some autobiographical stuff. It's really cool Uh What about what about movies? Do you have a favorite or at least favorite movie about Space or cosmology? You're like, can I not answer some of this? Yes. Yes. Yes. Um, okay, so so

Favorite yes, um So there aren't a lot of movies where I feel like the cosmology like cosmology is hard to Have as a topic of a movie because it's just too big a topic and like stuff happens on cosmological time scales, which is like incredibly long times and so Having something happen within a movie time frame is really hard. Um But uh, there's a movie that I really liked for how it portrayed the scientist and it had some some cosmology ish stuff in it um

So that was sunshine. Okay, which the science is wrong Just putting that out there. It's it's about the sun has like burned out or is burning out and they have to fix it And none of that can happen. All of that's false. All that's fake But it's done really well in terms of like they have physicists who who acts like a physicist and and like they have people Who talk like scientists and I kind of just enjoyed it. Um, so I thought and then there's like a monster thing So anyway, but I thought that was done really well. Um I really enjoyed gravity. There is also bad physics in gravity in some places, but I thought it was a beautiful movie Um, and it it portrayed space very well. How do you feel about space balls? I think it was funny. It's been a long time

Oh, hell. Yes. That was good. Yeah other space movies like the martian was fun. Interstellar had a very pretty black hole in it Okay That's that you were being you were being very complimentary and that is duly noted You are being a very nice person The black hole in the wormhole in interstellar were very beautifully done and done with um With proper relativistic equations. It was very clever because what they did is they they they had these simulations that are very very difficult and take a very long time on supercomputers and they gave them to the the um The people who do movie graphics who have really powerful super supercomputers

And they're like, no, we need to do this black hole properly So they calculated it and now they got some like papers out of it because The result was such such a good calculation that they were able to get actual science out of the The calculation done for the graphics in the movie because movies are better funded than yeah Yeah, yeah, so it was a very good move. Um, but but you should you should know that that the black hole in in interstellar Although there are some aspects that are done very faithfully. They did have they did tweak some things So it actually would look pretty different. Um, if we saw an actual black hole in real life So there are a couple of things that were tweaked that were a bit different

So speaking of movies Katie and I were supposed to go to one after this interview and we did But we barely made it because this is all really great information We hadn't even gotten to the wrap of fire round of all of your questions So I asked your questions We raced to the showing and this poor woman had to smuggle a burrito and eat it in the theater I'm so sorry. By the way, we saw murder on the orion express It features a very bizarre mustache I will give it that

So stay tuned the first two-parter analogies history when we resume with your questions So you now have a solid base tune in next week to hear astro katie address your questions including Is there a name for the disorientation and panic one feels when considering the vastness of the universe? There is are any of the sci-fi movie methods to save the planet plausible? Or are we basically doomed if an asteroid uses us as a target? Will the universe expand forever? What's the deal with multiverses? Are there aliens?

And speaking of your submissions, I wanted to let you know I totally see the reviews you write on itunes and it's so appreciated Rating and reviewing and subscribing is free It takes very little time and it helps oligies stay up there in the science charts. So more folks know about it So thank you so much katie is at astro katie on twitter where she has approximately one billion trillion followers And she is academic nomad on instagram So thank you to all you oligites for tweeting and gramming and memeing at us and to all the folks on patreon who make the show possible

It is currently 4 a.m. On a friday night and i'm recording this to send it off to steven ray morris He's going to help edit it and your funding is making this dream project possible And putting a lot of facts in a lot of human minds You can also keep the show going by stopping at oligiesmerch.com. We have New pins in stock Clock pins and amazing shimmery bird pins for eight bucks each designed by shannon feltis with merch help from bonnie dutch Um, I also want you to know that yes, it's super late at night and i'm recording this

partly because uh the mass of porridge That occupies the space where a brain would be had to spend a little longer trying to understand and explain these concepts that I thought and uh right now as I record this Middle of the night my neighbors had been blasting techno christmas pop songs For four hours while I was learning about wormholes The world feels very surreal. Also Congratulations to anyone who made it to the end of this episode. Man, you stuck it out. I appreciate that. Um as a special Thanks, i'm gonna tell you a secret that no one in the world knows earlier tonight. I ate cereal

I bought from a gas station and I loved it So if you listen to the end of this episode feel free to holler at oligies or ally ward I'm sure I'll have a new secret for you next week at the very end when we are back with katie max q&a So until then ask smart people dumb questions because they love it and we're just tiny meat blobs on a dust Spec, so let's just live can we live? Okay, bye Meteorology