Planetary Radio: Space Exploration, Astronomy and Science - Katie Mack and The End of Everything

Episode Date: August 26, 2020

Known as Astrokatie to her 370 thousand Twitter followers, astrophysicist and cosmologist Katie Mack has written a funny, fantastic guide to the end of the universe. The End of Everything (Astrophysically Speaking) explores five major scenarios for the big finish of the cosmos that scientists currently consider to be possible. We’ll award a copy of Katie’s book to the winner of this week’s What’s Up space trivia contest. Links and more are at https://www.planetary.org/planetary-radio/0826-2020-katie-mack-end-of-everythingSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Katie Mack on our impending cosmic doom and other cheerful topics this week on Planetary Radio. Welcome. I'm Matt Kaplan of the Planetary Society with more of the human adventure across our solar system and way beyond. Cosmologist and science communicator Katie Mack joins us to talk about her truly delightful new book. It's called The End of Everything, astrophysically speaking. We'll take you through the five ways the universe and everything in it could end, just possibly at any moment. Then we'll join Bruce Betts for a look at the especially crowded night sky. You might win a copy of Katie's book in the Space Trivia Contest.

Happy birthday, Mars Reconnaissance Orbiter. It has been 15 years since the launch of our spy in the Martian sky. To celebrate, the August 21st edition of the downlink is topped by a real stunner of an MRO image, rippled powder blue dunes on the surface of the red planet. Okay, the color was added to heighten the texture, but still. Perseverance and the UAE's Hope spacecraft are doing just fine.

Both successfully completed small course adjustments, and both are still set to arrive at Mars in February, along with China's Tianwen-1. Speaking of Perseverance, NASA has created a review board to analyze the agency's ambitious plan to bring bits of Mars to Earth. And we now know which astronauts will be carried by the first operational mission by SpaceX Crew Dragon vehicle. It's set to launch toward the International Space Station on October 23rd. You can visit planetary.org slash downlink to see their names and much, much more. Here's a reminder

that there may still be time to sign up for the first ever Virtual Humans to Mars Summit. Details including the agenda, speaker list, and registration info are at exploremars.org. Dr. Katie, or Catherine Mack, is a theoretical astrophysicist and cosmologist who studies everything, by which I mean the universe from its beginning to its end. And now she has written a book about that end. Katie is an assistant professor of physics at North Carolina State University, where she is also a member of physics at North Carolina State University, where she is also a member of the Leadership in Public Science Cluster. You'll find her work in Scientific American, Slate, and Sky and Telescope, among other places. Her 370,000 Twitter followers

know her as Astro Katie. And I bet a few of you have joined us for this conversation Katie and I had a few days ago. Katie, what a pleasure to welcome you to Planetary Radio. Thank you for joining us, and thank you for this terrific book, The End of Everything, Astrophysically Speaking. Welcome to the show. Thanks. Thanks so much for having me. So you want to know what I would write if I was doing a blurb for this book? Sure, yeah, please. Here you go. A fascinating, delightful romp toward our ultimate doom. Awesome. I'll take it. I'm so glad. Do you remember the moment when it hit you that everything, I mean, everything could end at any second? Yeah. Yeah. You know, there are these times when you're studying something like astronomy,

you're studying things that are far away and distant and mathematical. And so most of the time it feels very separate from your daily life. But there was this time when I was at this sort of dessert night for the undergraduate astronomy course at Caltech. And this professor was talking about the early universe and this inflation period where the universe expanded very, very rapidly for a time in the early universe. And then that inflation period stopped and the regular expansion of the universe took over from there. And he was saying that, you know, we don't know why inflation happened or why it started or why it stopped. And we don't know why inflation happened or why it started or why it stopped. And we don't know that something like that couldn't just happen right now and just sort of massively rip the universe apart.

And I was like, wait a minute. I'm not okay with this. And I realized that some of these massively powerful processes that happen out there in the cosmos, they seem really separate from us. But because we don't know exactly how they work, we can't say for sure that something can't happen to us and actually affect us. We see violent events out there in the universe. There's nothing to say that they can't really happen here. And that was a moment that really sort of shook me because I hadn't made that connection before. I also love that this happened as you were sitting on the floor at your professor's feet and he had his young daughter in his lap.

Yeah. Yeah. He had this little three-year-old girl sort of sitting there, totally oblivious, no idea what was happening. And her dad's sitting there talking about the universe suddenly coming to an end. It was a very surreal moment. And of course, as you mentioned in the book, and we may get to this, it could happen and we won't even be aware of it. We'll just be gone because our nervous system wouldn't have time to react. Yeah, yeah. So that's one of the end of universe scenarios I talk about, vacuum decay. And

the main features of it are that it's unpredictable and that you wouldn't really notice it because it's so quick and you wouldn't see it coming. So yeah, I guess we can talk about that a little bit more later. But that kind of thing definitely gives you pause sometimes. What is your answer when people like me ask, what do you do? You talk about this fairly upfront in the book, and it seems like you are kind of between the two worlds of physics that we mostly hear about. Yeah, yeah. So I work in an area that is kind of between astrophysics and particle physics. So I do cosmology, and that's the study of the universe from beginning to end.

And I'm on the theoretical side of that. But really, the place I sit is I sit right between the people who come up with new theories of how physics works or how the universe works and the people who are actually out there with telescopes and experiments testing these ideas. And my job is really to try to make connections between the theories and the observations or experiments to try to find out what we can do with observations or experiments that we can do now or in the future that will give us some insight into the theories that people are coming up with. Yeah. So really kind of in between two different worlds. I mean, the worlds of the impossibly huge and the impossibly small, but also between the theorists and the experimentalists. Yeah, yeah. And it's an interesting place to be because it means that I have to really keep track of what's going on in all of those realms. So I have to take a really big picture view of not just the sort of technological aspects and the theories,

but also how everything fits together in the, in the cosmos, because in the universe, we study the largest things, but physics is fundamentally driven by theories that govern the very small and, and you have to kind of make those big connections and see how that all plays out in, in the cosmos itself. Well, this may be more work, but it doesn't sound like it's really a downside. I mean, it kind of sounds like fun. Oh, it's super fun. Yeah, it's very fun. It's very creative, trying to make these new connections. And the idea that I have to know about all of the things that are going on and all of the theories

and stuff, that's a good thing as far as I'm concerned. It means that I can take a very broad view and I get to learn about a lot of really interesting topics and a lot of really interesting areas of physics and astronomy. We get to talk about cosmology now and then on planetary radio, even though the planetary society, as you might imagine, mostly pays attention to small round things, fairly insignificant probably in your view. But it's such fun to do this. And when we do, I mean, it has become obvious to me something you point out in the book that a lot of cosmology and popular writing about it is devoted to the beginning of the universe, what you delightfully call the Infernoverse. Yeah. Why do you think our eventual ending gets less attention, at least until your book?

Well, I think there are a few reasons. One is that it's less direct, the information we get about the end of the universe. We have to extrapolate from what we know about the current universe, the history of the cosmos, into this unknown time in the future. But when I say that this is less direct, I mean that when we work on the beginning of the universe, we really are actually looking at it. When we see out into the distance in the cosmos, we're seeing into the past. And so we can see the big bang. We can see the sort of end stages of the big bang very directly just by looking far enough away. That's much more solid in terms of what we know about the

beginning of the universe. And I think that a lot of people think of the end of the universe as something that's just very much speculative and maybe not as important in some senses. But I think that it can be a really important exercise to go through thinking through what our theories predict about the future and how physics will change as the universe evolves. I think that's a really useful exercise as a way of thinking about what our theories mean and how to conceptualize these ideas. I think you make this case very, very well in the book. There's a statement in here that I wonder about. You say in the book that our understanding is being advanced, thank goodness, by new technological and theoretical tools.

I get the technological part. You talk about some of those, but what do you mean by theoretical tools? Well, there are a lot of insights that we can gain by examining the kind of mathematical structures of the models that we use to talk about the universe. So there's a lot of work in areas like string theory, where we're trying to find a way to reconcile quantum mechanics and gravity, which don't seem to play well together. So string theory is an attempt to bring that all together into one big theory that covers everything. That's really just theoretical tools at the moment because we don't have a way to test that stuff experimentally. We can gain insights into the structures of the theory and into possible implications just by doing the theoretical work. And so when I say new theoretical tools,

I mean new ideas, new structures, new frameworks for how physics works that can then be hopefully tested with experiments. With these new tools, would you say that we've made progress on both ends? I mean, we seem to know more about the beginning than we do toward the ending. Is this still largely pointing outward, though, and saying, here be dragons? We are making progress, I think. We're getting a lot of new data about how the universe has evolved over time. And that's super important for understanding both the beginning and the ending. So understanding where we came from, how astrophysics has changed since the early times to today. We are able to study more and more galaxies out there in the universe, which means we're getting a better mapping of the history of the expansion of the universe, the history of the buildup of

structure, by which I mean galaxies and clusters of galaxies and so on. And we're getting new tools all the time. I mean, between the new particle experiments where we have a ton of new experiments that are looking at various aspects of particle physics, neutrinos, how neutrino physics works, which is a whole big topic and lots of interesting mysteries in there. We're also getting new tools for studying the cosmos. And one of the biggest ones is gravitational waves, where we're able to now pick up the vibrations of space itself as black holes are colliding in other galaxies. And this is just a whole new window on the cosmos where we can sort of feel the vibrations of space as these big violent events are happening.

And that teaches us about those events themselves, you know, how black holes come together and things like that, but also about gravity. And we're also able to learn a little bit about the structure of the universe itself by how the gravitational waves are traveling through the universe. So we do have a lot of new tools and we're getting new insights all the time into the cosmos and the structure of physics. It is so thrilling to be able to talk now and then about gravitational wave astronomy, mean, it's going to be really amazing over the next few decades as we get more of that information and we see the time in the universe to talk. We don't, of course. But maybe you could briefly take us through the five scenarios that are really the heart, the singularity of this book. And we can do them one at a time, but I'm afraid they may have to be sort of elevator

pitch length explanations. So tell us about the first one, the big crunch. The big crunch is the idea that the current expansion of the universe might reverse. Right now, we know that the universe is expanding. Galaxies are getting farther apart from each other in general. We didn't know for a long time if that expansion would continue forever or if the expansion would stop and turn around and everything would come crashing back together. And the big crunch is this idea that maybe the expansion would stop and turn around, and maybe everything would come back, and we'd get this hot, dense state very much like the beginning of the universe, and that would destroy everything in the cosmos. We think that's probably not going to happen, but for a long time, it was thought to be the most likely scenario.

Perhaps most likely scenario, at least from my reading of the book, is this next one, most likely scenario, at least from my reading of the book, is this next one, heat death. And I want to open this by, it brought back a memory. Back in college, an engineer friend of mine and I were asked by a very good friend of ours, very smart guy, well-educated, why the room doesn't get colder if you leave the refrigerator door open. Yeah. I remember feeling disappointed that he could have come so far in his education without having been taught about this. That leads us right into heat death, doesn't it? Yeah, so that connects the idea of entropy. So entropy is just disorder, really.

It's a way of talking about how disordered system of objects or physical things becomes. So there's this second law of thermodynamics, which is a rule that seems to apply very strictly in the universe that says that entropy increases over time, meaning that things become disordered. And it means that you can't have a perfectly efficient machine. There's always going to be a little bit of loss through friction or something like that. And that's why when you leave the refrigerator door open, the refrigerator is putting energy into cooling the section inside, but some of that energy is also room will get hotter overall because that waste heat is building up because there's always some kind of waste heat when you do any kind of process in physics. So the heat death is the idea that as the universe evolves into the future, entropy is always increasing

and there's a kind of buildup of waste heat of the stuff in the cosmos. Now, the universe is also expanding. So all of the matter and radiation, everything is being diluted out. And so on average, the universe itself is getting colder and darker and emptier, but also everything is decaying through this process of increasing entropy. And over time, everything will be decayed away to just a tiny amount of trace leftover waste heat of the cosmos. and that'll be all that's left in the universe. Was I right? Is this now at least currently seen as the most likely big finish for the universe? Yeah, it seems to be the direction we're heading because we see that the

universe is expanding and it's actually speeding up in its expansion. So this idea that everything will continue to get farther and farther apart seems to be borne out by the data. Our best guess as to what's making the expansion happen faster all the time is, well, there's something that's making the expansion speed up. We call it dark energy. We don't know what it is, but our best guess is that it's a cosmological constant, which is just a property of space that there's this inherent expansion built into space.

It's an idea that Einstein first came up with. And if that's what the dark energy is, it just leads to this cold, dark, empty universe and the heat death. I love that at one point, I think it's one of the footnotes you mentioned, that good old Albert, wasn't he wrong about anything? It's so frustrating. And you do address at some length, the cosmological constant, it comes up several times. And that maybe it's just a property of the universe that maybe, like you said, we shouldn't be thinking of it as like another particle or a field. Yeah. Yeah. Yeah. It seems like it's very possible,

maybe even likely that it's just something that exists in the universe that when you have a bit of space, there's some cosmological constant associated with that bit of space and it just expands it over time. And because the universe is expanding all the time and there's more and more space, there's then more and more of this cosmological constant, which means that the expansion continues. And so the density of this stretchiness, if you want to call it that, stays the same. And so that ends up accelerating the expansion of the universe. And we won't get into it here, but you also talk about what if the cosmological constant isn't so constant. But that's another good reason to read the book,

everybody. It's also while you're talking about the heat death of the universe that you first mention the possible appearance, in fact, not just possible, we know it happens, of something from nothing, from what I was taught growing up was just the vacuum. In fact, you specify a sperm whale and a bowl of petunias, by the way, and you're not fooling anybody here. I hope you have your towel handy. Yeah. We know that there can be random fluctuations in the universe, and this is indeed an idea that was discussed in Douglas Adams' Hitchhiker's Guide to the Galaxy, but these random fluctuations can cause apparently unlikely things to happen. And I do go into a bit in the book about what kinds of unlikely things we might expect to see.

We better go on to the next way everything might end, the big rip. Yeah, so the big rip is based on the idea that maybe whatever's making the universe expand faster, dark energy is not a cosmological constant, but something that could change over time and get in some sense more powerful over time. And if that were to happen, it wouldn't just move galaxies apart from each other and make more empty space. It would actually also be inside galaxies tearing the galaxies themselves apart. So you would see that stars would be pulled away from their galaxies, planets would be pulled away from their stars, and even stars and planets would be

destroyed over time. And as you get closer and closer to this ultimate big rip event, atoms themselves would be pulled apart, and then space is kind of torn asunder, and that's the big rip. And that's a way for the universe to end in a very violent and complete manner. You mentioned a paper by physicist Robert Caldwell, which you say is one of your absolute favorites of all time. The title is Phantom Energy, Dark Energy with W Less Than Minus One Causes a Cosmic Doomsday. So this is what you read for fun. The great thing is that it's also what I read for work. This is part of my job is to keep track of these cosmic scenarios. And that's one of the ones that came out while I was in grad school.

And it's a really fun idea. Katie Mack has more doom, but no gloom right after this break. Greetings once again, Plan Red listeners. Bill Nye, the planetary guy here, CEO of the Planetary Society. You and I know better than to ask if another world shattering asteroid will come our way. The only question is when. Here at the Planetary Society, we're committed to protecting the planet. You can be a defender of Earth. We need you on our planetary defense team. It's the only large-scale natural disaster we can prevent.

Donate today at planetary.org slash defendEarth to power our crucial work with your gift. That's planetary.org slash defendEarth. Thank you for helping us save the world. Here's something else that's in this chapter about the big rip that caught me by surprise. Of course, a lot of this is wrapped up in calculating, figuring out the effect of gravity across multiple galaxies and huge regions of the universe. And you say that when you're doing this, you have to take into account not just the mass of something like the mass of a cloud of gas, but the pressure of the gas within it. That also enters into figuring out the gravity. What's up with this?

Yeah. So one of the things that Einstein's formulation of gravity, general relativity includes is that the gravitational effect of something isn't just the kind of mass of it, but also its pressure, also kind of the energy of the motion of the stuff inside. So when you look at gravity from Einstein's perspective, So when you look at gravity from Einstein's perspective, what's happening is that the mass of things or the sort of energy density of things is changing the shape of space around them. You often picture it as kind of a dent in space where a planet or a star is sitting or a really deep one where there's a black hole. really deep one where there's a black hole. So you can think of space being curved around massive objects and the amount of curvature, the amount of the effect on the shape of space is the mass and also the pressure of the object. Now I kind of get it because let's say molecules

bouncing around in a glass of water, Brownian motion, that's still energy. I mean, they're exerting pressure. Oh, okay. All right. Well, thank you. Next up, maybe the one that scares me the most. And it sounded like, even though you, at the end of the book, you quote from people, colleagues of yours in physics who aren't particularly bothered by this, you seem to be, it's vacuum delay. And it's- Vacuum decay. Oh, sorry, vacuum decay. And I was looking right at it. What would vacuum delay be, I wonder?

I hope it's delayed. It's in this chapter that you seem to kind of, you fondly look back on our existence and wish that the Large Hadron Collider hadn't destroyed the universe. Okay. The Large Hadron Collider is not powerful enough to destroy the universe. I want to make that really clear because there are a lot of people who think that it could. What happened with the Large Hadron Collider, how this fits into vacuum decay is that the Large Hadron Collider gave us some new insight into how particle physics works and suggested that vacuum decay could be

possible. It might've always been possible. Maybe we just wouldn't know about it if it weren't for the Large Hadron Collider. So it's really doing us a favor. It's not making this happen, but it's giving us a heads up that maybe this could happen. So the way that vacuum decay works is we know because of experiments with the Large Hadron Collider that there is an energy field called the Higgs field that pervades all of space. We know that because we've detected the Higgs boson, which is a particle field called the Higgs field that pervades all of space. We know that because we've detected the Higgs boson, which is a particle associated with this Higgs field. And this Higgs field has something to do with how particle physics works in our universe. People often talk about the Higgs particle in connection with how particles got mass

in the early universe. That's why people sometimes call it the God particle, because it imbued particles in the early universe with mass in some way. It's really the Higgs field that was associated with that. What happened was the Higgs field, this energy field through space, there's some value associated with the Higgs field and that value changed in the early universe from one thing to another. When it changed, that changed how physics works and it allowed the particles we see in the universe now to exist and the interactions of physics to happen the way they do now. And so it allowed for the existence of atoms and molecules and

chemistry and life and all of that. So we like the Higgs field being where it's at because that allows us to exist. What the Large Hadron Collider told us is that based on its measurements of the masses of particles and things, it suggested maybe the current value of the Higgs field is not necessarily the one it's going to have all the time. It suggested that maybe the Higgs field is not entirely stable, meaning that something could happen somewhere in space, a quantum event, a quantum tunneling event could happen to the Higgs field at one point in space. And that would change the value of the Higgs field at that point. But that would create a little bubble of a region where the Higgs field has a different value. And that's really a different kind of space. It's called a true vacuum. And this true vacuum bubble would then expand out at the speed

of light or roughly the speed of light and just destroy everything in its path. And if you ended up inside that bubble of true vacuum, your molecules wouldn't hold together anymore because particle physics would no longer work the way that you're used to it working. That bubble would just destroy the whole universe. And the reason that it's scary to a lot of people is because it's governed by a quantum transition, a quantum tunneling event. And what we know about those kinds of events, about a lot of things in quantum mechanics, is we really can't predict when it'll happen or where it'll happen. It's a random occurrence. So we can give a timescale. We can say that it's probably not going to happen anytime soon. We can say that the likelihood is that it would have to wait 10 to the power of 100 years for this to occur. But we can't say for certain that it won't happen soon.

So that's what makes people nervous. And I want to just make sure that I say, you know, don't worry about vacuum decay. We don't even know for sure if it could happen and the chance of it happening, like you're much more likely to get hit by a meteor and a lightning bolt and win the lottery all at the same time than, you know, than vacuum decay occurring. So don't worry about it, but it is intriguing because it's this thing that ties into how fundamental physics works in our universe. And it would be such an extreme violent event and just out of nowhere. I'm reassured and I love it. And we've already made one literary reference to good old Douglas Adams. You work Kurt Vonnegut in here as well, because you make

the comparison to ice nine, that form of water that whenever it comes into contact with other water, freezes well below 32 degrees, or excuse me, well above 32 degrees Fahrenheit. And eventually the whole world is ice. It just spreads. Yeah. Yeah. And that's how vacuum decay would work. The little bit of space next to the bubble would be transitioned to the bubble and that would go on indefinitely as the bubble is expanding. It would spread at the speed of light and therefore we wouldn't see it coming. Right. Yeah. Yeah. Because if something's coming at you at the speed of light, by the time the light from it gets to you to warn you that it's coming, it's already on top of you. So you would

have no way of knowing it's about to happen. You wouldn't even know that it did happen because, you know, let's say it actually hits you, your nerve impulses don't travel that fast. So by the time the signal got to you that something had happened, you would no longer exist. So in that sense, it's very humane. You don't have to worry about it. You don't see it coming. You don't feel it. You kind of don't notice. And then it destroys everything. So nobody's left to miss you. There's no tragic aftermath. It's just over. Everything's over. Ignorance is truly bliss. There's a line in this chapter that also made me give a long sigh. You said, you'll just have to trust me that if you decide to go and learn the mathematics behind

all this, it gets much cooler. I feel so inadequate. It's as if you and people who know the math have special glasses that let you see the beauty of the world and the universe far more deeply than I can without the math. Well, I definitely think that learning more about how the universe works does make it more beautiful. And understanding these mathematical structures and these physical concepts, I think, can give you a new appreciation for physics and for the world we live in. And I feel very, very fortunate to have access to some of that and to be able to see the universe in that way. I envy you. Okay, we're in the homestretch here. We've reached the bounce. Bouncing cosmologies, it's sort of a set of different ideas where the universe would go through some kind of cycle or transition where

when the universe ends, it's not forever ending and everything's over, but it would start a new cycle. A new universe would be born out of the ashes of our own. So you can have a situation where there's a kind of big crunch type thing that then leads to a new Big Bang or a heat death where a new Big Bang sort of sprouts out of that. There are a few different ways you can have a collision of adjacent universes that sparks a new Big Bang. There are a couple of different ways that this can happen, but bouncing cosmologies or cyclic cosmologies all have in common that the start of our universe was due to the end of a previous universe. And maybe when our universe is over, a new one will begin. A lot of people find bouncing cosmologies to be kind of hopeful because even if our universe

is totally destroyed and everything that we ever had here is gone, maybe something else will occur afterward. And some people find comfort in that. you know, information of some sort, maybe gravitational waves or some kind of trace that could tell us something about the previous cycle or could carry information from our universe into the next one. Is it possible, if the bounce is the correct scenario for the big finish and a new beginning, that you and I have had this conversation before 11 billion times, or does quantum mechanics eliminate that? I think that there's no particularly good reason to believe that the next cycle would be particularly similar to ours. So I think that enough weird things could happen that you wouldn't expect a lot of similarity on that level for a future universe. There are some interesting ideas in quantum mechanics where every time a quantum

event occurs, a new universe branches out. And so there could be infinite copies of us in these parallel universes that are totally inaccessible to us through quantum mechanics. But in terms of the next cycle of our universe occurring, it's a little unlikely it would look like ours. Although there are certain scenarios in the heat death where you can have these sort of sudden random reoccurrences of our universe in any configuration our universe ever had. So in those situations, you can have kind of this moment repeated over and over again forever just through the random rearrangement of particles in a post-heat death universe. And that's a particularly weird idea that I get into a bit in the heat death chapter. And that's a very fun and sort of mind-bending

way of looking at the possible distant future of our universe. mind-bending way of looking at the possible distant future of our universe. Mind-bending indeed. Yeah. All right. Those are the big five. You can read much more about them in the book. I want to begin our close here by talking a little bit about where we're headed. I mean, what are you looking forward to? And something that you mentioned in the book, another one of these new tools that is going to help us understand our place in the universe and maybe our future. I'm going to be moderating an event about planetary defense efforts in a few days. And you mentioned that you recently attended a session on this topic and the Large Synoptic Survey Telescope, now known as the Vera Rubin Observatory, was brought up because it's going to help us find these little rocks that threaten

our planet, not the whole universe, but that it's going to be useful to folks like you too. Yeah, yeah. So that's going to be an amazing survey of the sky that's going to show us billions of galaxies out there in the universe. We'll be able to catalog just a huge number of galaxies and supernovae, and that's going to allow us to map out the structure of the universe as we never could before, and to learn about dark energy and dark matter and

kind of the structure of our cosmos. And so that's going to give us some huge clues about both the history of the cosmos and the future. What else are you looking forward to? I mean, are there other tools or are there theoretical developments that have you worked up looking forward to where they may take us? I'm really looking forward to new particle physics experiments. There's this proposed experiment, the Future Circular Collider, which would be kind of a much larger version of the Large Hadron Collider that could give us new insights into particle physics. I'm really excited about some of these new observatories like the Vera Rubin Observatory,

space-based experiments or observations like the James Webb Space Telescope and some other space telescopes that are going to show us early galaxies, some of the first galaxies in the universe, and teach us about the history of our cosmos. So there are a lot of ideas like that. And then gravitational waves, I'm very, very excited about what we're going to learn from gravitational waves, seeing collisions of black holes out there in distant galaxies. And on the theoretical side, I'm very interested to see where And on the theoretical side, I'm very interested to see where ideas around string theory and around what's called holography can take us, where we're learning about connections between different areas of physics that suggest some really strange things about how physics works. I talk about this a little bit in the book, where it's possible that space and time are not really fundamental to our universe,

that our universe is really built on a different kind of mathematical structure and space and time are emergent, which means that we exist in space and time and we deal with space and time. But really what's happening is something much more abstract, much more mathematical, and we kind of just perceive space and time being real, but they're not strictly what our universe is built out of, which is a very strange and intriguing idea. I love this stuff. I think you say that space-time is not fundamental.

At least you quote somebody saying that. Yeah, yeah. It's a very weird and kind of unsettling thing to think about. It's a very weird and kind of unsettling thing to think about. You muse toward the end of the book about the Drake equation, that great thought experiment by Frank Drake that we've talked about many times in this show. You're not in the business of figuring out how to detect intelligent life elsewhere in the universe, but you still find great significance in what this equation attempts to do. Yeah. So the thing about the Drake equation that I was connecting with in this book is that the Drake equation is a great way to kind of figure out what the questions are that we need to be asking. You can write down this equation,

you can put numbers into all of the terms and you get a number out. And the number that you get out of the equation is not really telling you something new because the numbers and you get a number out and the number that you get out of the equation is not really, is not really telling you something new because the numbers that you put in are all very uncertain. So, so the number that you get out is not the important thing about the Drake equation. The important thing is going through the exercise of thinking like, what are the, what are the numbers I need to put in here? What are the factors that play into this question of how many alien messages can I expect on my galactic voicemail? And in, in terms of cosmology,

in terms of thinking about the end of the universe, it's kind of a similar idea. You know, we want to know how the universe is going to end. There are a lot of things we don't know yet. And by thinking about how the universe is going to end, we figure out like, okay, what are the, what are the ingredients that go into this? What do we need to know to answer this question?

And what can trying to figure that out tell us about how physics works and how the universe works? So getting there is half or maybe more than half the fun. Yeah, I think so. I think that we're not going to see the end of the universe. I hope not, but we're going to learn a lot along the way and we can project our understanding into the future and that can be a really great and fascinating exercise. We've reached the end, but I'm glad I've already asked you to pull out from your website this great poem that you have there, which you titled Disorientation. And you've very kindly agreed to read a bit of it to us. We don't have time for the whole thing, but maybe you could take on those last four

stanzas. Sure, sure. I want to utterly disorient you and let you navigate back by the stars. I want you to lose yourself and find it again, not just here, but everywhere, in everything. I want you to believe that the universe is a vast, random, uncaring place in which our species, our world, has absolutely no significance. And I want you to believe that the only response is to make our own beauty and meaning and to share it while we can. I want to make you wonder what is out there, what dreams may come in waves of radiation across the breadth of an endless expanse, what we may know given time, and what splendors might never, ever reach us. I want to make it mean something to you, that you are in the cosmos,

that you are of the cosmos, that you were born from stardust and to stardust you will return, that you are a way for the universe to be in awe of itself. What a lovely way to end a lovely conversation. Thank you so much, Katie. Thank you.

It's really great to talk with you. That's cosmologist and science communicator Katie Mack of astrokatie.com. The end of everything astrophysically speaking is published by Scribner. We've got a link to the book on this week's episode page at planetary.org slash radio. And a copy just might be yours if you stick around for Bruce. Time for What's Up on Planetary Radio. Bruce Betts is the chief scientist of the Planetary Society. And that means he does a whole bunch of stuff for us.

I don't even know if you have to be a scientist to do this, but he also runs our light sail program. And that seems more engineering to me. What do you think? Yes, it's management. But I'm also the camera guy. We've been getting some cool pictures lately. Oh, yeah. How many more of those are available now?

I know you've been sharing them with colleagues. I have. We'll get more up, but you should be able to find more at sail.planetary.org, at least a couple of the recent ones, if you follow the pictures link. They're looking pretty, pretty cool. Hurricanes and Bahamas and stuff. They're more than cool. Do check those out. I'm glad that that came up. Speaking of up, what else is there? Oh, nice segue. Early evening, or just evening in general, it's a planet party. We've got Jupiter looking super bright over in the southeast,

Saturn to its lower left looking yellowish. And coming up now, just an hour or so after twilight, is really bright Mars, brighter than the brightest star in the sky, but still outshone by Jupiter. You'll find that in the east to the left of Jupiter and Saturn. Pre-dawn, also parties happening. We've got one planet, but it's really bright, and that's Venus. And you can find Pollux and Castor to the left of it, and Procyon, which is the bright star in Canis Minor, to the lower right of Venus. So all sorts of stuff to look at.

But wait, don't order yet. We can also get the moon involved on the 28th. It will be fairly near Jupiter. And on the 5th of September, it will be very close, just a couple moon diameters or less to Mars. So cool conjunction of moon and Mars on the 5th. Nice way to celebrate the season. We move on to this week in space history. It was this week in 1979 that Pioneer 11 became the first spacecraft to fly by Saturn. A real pioneer. Oh, nice. Speaking of nice, random space fact. Oh, that's nice. Per unit area, Neptune receives only one nine hundredth the amount of sunlight received by Earth. That's why it's really cold out there. Cold and dark. Cold and quite dark. I mean, you know, the sun's really bright, but still.

Yeah, I imagine their gas bills for heating would be huge, but there's gas everywhere, so it's okay. Gosh, that's positive. All right, contest time. We asked you, what is the wavelength of the SuperCam laser on the Perseverance rover? How'd we do, Matt? I'm going to start with this one from Ian Jackson in Germany. Seems to be an easy one this week. Bruce feeling guilty about the black hole question? Maybe.

And I'm sort of going to let Gene Lewin in Washington answer with a poem, and you'll find out why I say sort of. SuperCam can proudly tout the ability to look about, and through Raman spectroscopy discern a sample's chemistry. A neodymium YAG device, this laser fires quite precise, revealing possible life in Martian dirts between 281 and 563 terahertz. Great work. The only problem is you asked for it in wavelength, and he gave it to us in terahertz. And it's accurate. I checked it. I converted the wavelength to frequency, and it works.

One person's wavelength is another person's frequency. I've always been a wavelength fan, but people, you know, especially those radio astronomers, they think in frequency. Me too, because I'm a radio guy. Oh, you are a radio guy. So I think frequencies, wavelengths are just, that's like for short wave people and I guess astronomers, But thank you, Gene. Good job. Not our winner. Here's the winner.

John Bierstaker. It's my favorite kind of steak. Bet he hasn't heard that one before. In Massachusetts. First time winner. 1064 nanometers or 532 nanometers for the Raman spectroscopy work that it also does with the same laser,

as we learned from the episode. He adds, John, congratulations. You have won yourself a copy of Lou Friedman's new book, Planetary Adventures, from Moscow to Mars, from Page Publishing. It was the source of all those great stories I talked with Lou about a couple of weeks ago. Cool. I got more. Here's another poem from Maureen Benz in Washington. Upon listening to the podcast, I heard men of science speak.

The super cam laser was the topic of the week. Measurements of this and that, though nary a mention concerning leaders, the key wavelength, 1064, is, of course, in nanometers. So good effort. And then, not really a response to the contest, but this comment from Pavel Parsonsik or Parsvenchik in Scotland. I'm Adam Bruce.

Hope you're as excited as I am about Perseverance landing on Mars. Just imagine what awesome new discoveries it will bring. Will it find a rubber asteroid? Because that sure would be nice to find in my mailbox. Nice try, Bob. We'll get back to them before too long, I'm sure. If they find a rubber asteroid, I'm sure they'll try to prepare it for sample return. Well, I'll be able to squeeze it down and carry more mash back.

Yeah. Well, I'll be able to squeeze it down and carry more mass back. We'll have to take a rubber asteroid squeezer, the newest instrument for the follow-on mission. They should have put one on the sample target. Moving on. So stick with me on this one. Here's your new trivia contest. Assuming a combined Greek and Roman pantheon mythology. Within this mythology, which planet is named after the earliest in other words the oldest God? Go to

planetary.org slash radio contest. In case there's any confusion I'll stick with in our solar system. You have until Wednesday September 2nd, at 2 p.m. Pacific time to get us the answer for this one. And guess what we're giving away? Now you already know.

It's The End of Everything, that great book from Katie Mack. The End of Everything, astrophysically speaking, is the subtitle from Scribner. I hope you will love that book as much as I did. It was great fun, just like the conversation we had with Katie a few minutes ago. All right, everybody, go out there, look up the night sky and think about your favorite utensil. Thank you and good night. Oh, I could probably do better than this, but off the top of my head, a barbecue spatula, the ones with the really long handles, so you don't get burned.

That's Bruce Betts. Even after all this, he is still the very practical chief scientist at the Planetary Society, who comes to us every week as part of What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its universally marvelous members. Join our little cosmos at planetary.org membership. Mark Hilverda is our associate producer. Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser at Astro.