StarTalk Radio - Cosmic Queries – The Big Stretch

Episode Date: October 22, 2024

What is fire? How do gravitational waves ripple through space-time? Neil deGrasse Tyson and comedian Harrison Greenbaum answer grab bag questions about why supernovae form black holes, photons, the singularity, and more!NOTE: StarTalk+ Patrons can listen to this entire episode commercial-free here: https://startalkmedia.com/show/cosmic-queries-the-big-stretch/Thanks to our Patrons Tina Bartenfelder, scott white, Camelia Prodan, Wendy Tilles, Hank Hill, Cody White, Richard Vermillion, Lawrence Wolfe, darina spasova, Pablo Montufar, Alia Druid, Karthik, Jelmer van der Wijk, Anne ROBERTZ, Quentin, Sebastian Mueller, Marta Polo, Chelsea Mcclelland, Ross Hardie, Micheal, and Kevin Danielson for supporting us this week. Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. This is StarTalk. Neil deGrasse Tyson here, your personal astrophysicist. We're doing cosmic queries today. Grab bag. Yeah. And I look to my left.

I don't see Chuck Nice. Chuck, what did you do? We look a little different. Harrison Greenbaum, welcome back to Star Talk. Yes, it's so nice to be here. Thank you for having me. Yeah, last time it was BC, before COVID. That's right.

When you last made an appearance here. We had a whole pandemic in between. A whole pandemic in between. A whole pandemic in between. And also you had like a Las Vegas residency in there. Yeah, I went across the country and back at that time. And back. So just congratulations on where your talents have taken you. Thank you.

And now you're right here in my office at the American Museum of Natural History. As much going on here as the circus, I will say. No, well, the universe is a circus unto itself. Absolutely. And it's many more than three rings going on here as the circus, I will say. No, well, the universe is a circus unto itself. Absolutely. And it's many more than three rings going on there. Saturn's got rings. Multiple ring circus in the cosmos.

So this is a grab bag. Fantastic. And you've got the questions. I haven't seen them. And because it's a grab bag, it's a grab bag without an expert that we bring in. So I'm your expert. Fantastic. I'll do my best. If I don't know an answer, I'll just say, I don't know. Okay. Okay. But you have to, we have Siri. We do have, we have tools that are, you've got the ways to bail me out is what

you're saying. Okay. All right. We don't know. It you're saying? Okay. All right. If we don't know, it might be known. Okay. All right. So what do you have first? All right. So we have Lena McGrath. She writes, hello, Neil. I am Lena from Orlando.

Where do photons come from? For instance, are they already inside my birthday candles or are they created from the fire? Oh, I love that. Does not specify what birthday she is on. Does not. Does not. But the fact that she still uses candles. Yeah. What age would you say you stopped using candles? Once the cake is

too full. Yeah, I think I stopped at 30. Oh, wow. That's longer than I lasted. I made it high in there. I think after high school, I was candle free. So it's a great question. It's reminiscent of a famous essay from the 19th century written by Michael Faraday. And it's called, what is fire? Ooh. Because what is it? It's an emoji I use too

often. Oh, okay. I've seen the emoji. Can you touch it? Can you grab it? Can you hold it? Not really. grab it? Can you hold it? Not really. So what is it? So there's a famous essay from the 19th century. So a photon is a packet of energy, a pure energy, and it moves at the speed of light. It's the only thing it knows how to do, is move at the speed of light. And so if, by the way, energy can manifest in a dozen, many different ways, okay? You can have potential energy. Now, why is it that you can harm yourself by jumping out of a window? Okay, there's a reason for it.

Because when you hit the ground, energy killed you. I thought it was the sidewalk. Okay, you had energy in your body while you were falling. One Red Bull right before the show. And that, oh yes. And the energy kept accumulating as you fell faster and faster. Right. Then you hit the sidewalk. All the energy that was in you from your motion, kinetic energy, goes back into you as mechanical energy. And the only way your body can accommodate mechanical energy

is to break stuff because it takes energy to break your bones. Energy can manifest in different ways. And the higher you take the elevator before you jump out the window, the more energy you have to break your bones upon hitting the sidewalk. That's why jumps from higher altitudes will do more damage than from lower altitudes. But if you're watching this and thinking about it, don't do it. Do not try this at home. Don't do it.

Above a certain height, there's an air resistance, what's called a terminal velocity, where the air is absorbing away some of that energy. I am about to terminate. Be terminated. Terminal velocity to be terminated. So there are other ways that energy can be stored, like inside of an atom. An electron can sit in many different energy levels. The atom has energy levels within it.

It's not a continuous placement of energies. If there's an electron at a higher energy level, and something happens to make a drop to a lower energy level, it just lost energy. Where did it go? Actually, it can go in one of two places. If another atom hits it, some of the energy of that electron can go to the kinetic energy of the other atom as it careens off.

This happens a lot. So it's a kinetic energy. A flyby looting of its energy. All right. But occasionally, it just sort of jostles it. The electron de-excites, goes to a lower energy level. Where does that energy go? Bada-bing.

A photon is released from the atom of exactly the same energy as the difference between the energy levels of the electron. All the energy is accounted for. And the photon goes in a random direction at the speed of light. That's where photons come from. come from ways that used to be energy in an atom or the vibrations of atoms and molecules and other particles. And in those vibrations, it can lose energy by releasing a photon. And that's what's going on. And it happens in all kinds of ways.

If you have an electric stove and you turn it on and eventually it glows. It goes like blue, orange, different colors. I hope your stove doesn't glow blue. You can tell by the way, how much I cook by my inability to answer this question. You have no idea what a stove is.

You have no idea what you were right astrophysically, but in a kitchen you're completely wrong. Okay. So the hottest your stove is going to get is red hot. Gotcha. But if you could, if you had an infinite knob, it would go white hot and eventually blue hot. That's going to be my band name. If I ever form a band.

Infinite knob. Oh, infinite knob. Blue hot's better. One of those. Pick one. I'm good with you. I'll come see you. Okay, great. So the fact that the stove is glowing red is emitting light.

Red light. The fact that the stove is glowing red is emitting light, red light. So you have vibrating particles in the heating element of the stove, and those vibrations will actually release light. And that, in a way, is cooling the stove, except you keep pumping energy into the stove. Right. But if you turn off the stove, it's still glowing red,

but then it sort of fades away. Why? Because it's giving up all its energy without it being replaced. And if it's hot, but not glowing red, it's still giving off photons, but not red photons. If it's hot, generally, what is that? Do you remember? Don't touch it. No, still don't touch it until it's cool. So it would actually, if you put on infrared goggles, it would be glowing in the infrared. That's still a form of light. You can have infrared photons.

So all these ways will generate photons, and stars are doing it every moment of their lives, and photons are crisscrossing through the universe, and it'll continue that way until the last star dies. So what does that have to do with birthday candles? Oh, very good. Thank you for bringing it back on point. I feel like Lena is at home right now.

She's celebrating her birthday. The candle's already melted down. It's ruined the cake. It's like, Neil, where's the answer? So you have to give energy to the candle from somewhere else, a lighter or a match, right? There's no free lunch here, right? The energy's got to come. So, what that will do... Free cake.

Okay, free cake. You will light the the... The wick. You will light the wick of the candle, which is typically coated in wax. The candles are made of wax. So you ignite the wick that will use molten wax as a fuel source.

There you have it. Now, why doesn't the whole candle burn up in one instant? Because the wick is drawing the molten wax in, and if you have too much of the wax, it'll put out the flame. You need just the right amount to feed it and keep it going. And candles are beautiful this way, okay? If the candle gets sort of, you know, if you, if you, have you tried this? Who has candles anymore? But you have like a three inch candle, let's say, and it's got liquid there. If you sort of tip liquid towards the wick, you can extinguish the wick.

Right. You say, well, why is that if it's using the wick to light? Have you ever questioned this? I have a couple of scented candles. Most of them smell like my apartment burning down when I fall asleep. Why does the liquid wax put out the wick when the wick needs the liquid wax to burn? Right. Because it's too much at a given time.

It's too much. So the wick draws it at just the right amount that it could burn the little bitty drops that come in at the rate that you need. So the energy, the starter energy comes from the match or from a lighter and you hit the wick. Now the wick simply burns the wax. And wax is one of the great things that kept us lit for centuries. Wax candles, you know, 17th, 18th centuries.

We didn't have light bulbs, so candles was a thing. Wax candles. So wax is a fuel source. By the way, if you get wax hot enough, where it goes molten, and you just keep heating it, it can burn without a wick. What? So this happened to me at home. I ignited the entire surface of the liquid wax in the pot. I thought you told the police it was an accident.

No, I used to make candles, okay? I'm just trying to picture this birthday party. No, accident. No, I used to make candles, okay? I'm just trying to picture this birthday party. No, no, no. I used to make candles. So you melt the candles and you can dip. What happens is you dip a wick in, so it gets wet with wet wax. You put it in the air.

Room temperature air will cool the wax, and then it's a skinny candle. You dip it again, and it keeps building layers and layers until it has the thickness you want. Okay, that's one way to make it, as you make a dip candle. And normally, you just pour it into a mold. Okay, so I melted this pot.

I had all these candle shards, right? And you put them all in there, you pull out the dead wicks, and now I have liquid candle wax and i left it on the stove too long it ignited you can't put water on it oh no it is hotter than boiling water so if you put water in there the water will be heated start to boil and then it'll boil fragments of flaming wax out of the out of the so there's only one way to put out that fire throw it out the window hope its potential energy is high enough yeah now you're going to give it extra potential energy so or kinetic energy so no you got to take a lid and cover it, and that'll smother it.

That's a less exciting answer. It's totally less exciting, but I knew enough. You suffocated it. I knew enough about, yeah, you're suffocating it. I knew enough about thermodynamics that that's how you do that. So the candle doesn't all burn at once because it can only burn a little bit at a time, and it burns its way down. And there you have it.

Nice. Well, happy birthday, Lena, I assume. Yes, however old you are. Hi, I'm Ernie Carducci from Columbus, Ohio. I'm here with my son, Ernie, because we listen to StarTalk every night and support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

Oh, by the way, these are all our Patreon supporters. They pay. So you get to ask questions as a Patreon supporter at our entry-level amount, which is like $5 a month. So go for it. All right, so we have Alan Reyer. He wrote, hello, everyone. Waving emoji, cowboy emoji.

It's Alan from Lithuania. A lot of cowboys there. Always wondered about gravitational waves. Please explain how and what did they actually detect in 2015? Oh, very nice. Yeah. So that's the first detection of gravitational waves was then. Nice. Interestingly, it was the centennial, the near centennial. I think the prediction came out in 1916 but basically the centennial of einstein's prediction that such a thing even exists so it took a century to verify that what he predicted was correct so just to put that in context all right so the way this works is

um according to einstein's general theory of relativity where you're here and you have we say you have a gravitational force i don't know if you knew that but you do right i like it okay and the more mass you have the more is your gravitational force i've had an increasing amount of gravitational force over the last few years is that right okay so it'll go up according to your mass. And we can measure that, more importantly. If you move through space and time, then your gravitational field needs to respond to that in some way. Because it used to be over here, and now you're over there. Newton described gravity as just a force at a distance.

Okay? Action at a distance. But he was still mystifiedified how could it gap the vacuum of space what's going on how do we know each other how do we know about what why do we know why is he knew his equations worked so he went with it but that's some confidence it's still like i know these are right i can't i can't prove it, but I am 100% sure. I can't demonstrate it? What's going on?

In the mystery of the vacuum of space, but it's working. Exhibit A, trust me. Trust me. So it's working. And Einstein said, gravity is not so much action at a distance. Gravity is a is a disturbance in the fabric of space and time.

So disturbance is too violent. It is a shape of the fabric of space and time made by the existence of matter and energy wherever you might find it. Let's take a black hole, for example. A black hole is such a distortion of space and time that light cannot even escape. That's why we call it black. And you can't come out. It's a black hole. Best named thing there ever was, ever. So if you're just somebody wandering by a black hole, you'll feel your trajectory altered by it.

Newton would say that's action at a distance. Einstein would say that is the shape of curved space-time. And you're just following where space and time wants to bring you. It's like in NASCAR, are they actually turning left? No, because the track is banked. The bank turns them forth, turns the cars forward. I feel like the drivers

would be very upset by this. Like, what are we training for? Yeah, so their steering is primarily maneuvering in the traffic rather than making a left turn as they go around the track. So the track is shaping their path

in the same way space and time will shape the path of anything moving, but light is the best tracer of this. What happens when two black holes collide? OMG. Black holes collide. They are already a disturbance

in the space-time continuum now they come together it is such a disturbance that they will create a ripple in the fabric of space and time emanating at the speed of light a ripple because as they come closer and closer

they spiral and faster and faster and then they come together and right at that spiral and faster and faster, and then they come together, and right at that instant, poof, there's a ripple. The first of these that was discovered had been traveling for 3 billion years. How do you detect it? We need special equipment.

We call it LIGO, Laser Interferometer Gravitational Wave Observatory, sensibly abbreviated LIGO. So they have two, I forgot how long they were, kilometer-long tunnels evacuated, no air. They have lasers that simultaneously go up the tunnel and back from a mirror that's at the other end. These two laser beams know about each other. They are coherent. They march to the beat

of the same drummer when emitted. If on the up and back trip something happened to the fabric of space-time, then one of those paths will be slightly different from the other.

Slightly longer or slightly shorter. And then the waves will no longer match up. And you can conclude that something happened here that didn't happen there. They're at right angles to each other. So this wave, this gravitational wave, as it washes over the observatory, depending on which angle was oriented relative to the wave, they will stretch or expand by different amounts from each other. And they measure this. They measured it. They knew what two colliding black holes should look like in their experiment.

Matched up. The announcement gets made. Nobel Prize is awarded. Now, just for context. You said with a tone of voice that they were, it was later discovered that it was wrong. No, no, no. I have a follow-on to that. 2017, they took it back.

It turns out one of them just jostled the machine a little bit. No, they only discovered it in 2015. Nobel Prize is later. Gotcha. Okay, all right. So, many people don't know that Einstein wrote down the first equations that enabled the laser to be invented later on. This is crumbs on his plate. Right. Okay. When you're that brilliant, crumbs

do great things because you're focusing on the main events, like the theory of relativity and other things. The back page of his notebook just said tunnel laser. So Einstein invents a new theory of the universe, the general theory of relativity, that predicts the existence of gravitational waves. Shortly after that, he writes down the equation that permits the invention of the laser.

Decades later, people invent the laser. Decades after that, they use the laser to measure and discover the existence of gravitational waves. And entertain cats.

Yes. Einstein's a badass. 100%. People get Nobel Prizes off of crumbs that fell off his plate. He should have had eight Nobel Prizes.

Right. Did he get one? Yeah, he got one. He got one. Okay, good. He got one. But for other stuff. I mean, not for his greatest work he did for really important work but not his greatest work he demonstrated that atoms actually exist like that's pretty good that's yeah i would say

and he demonstrated that light comes in discrete packets called photons. Which we just talked about. We just talked about. So that's good. That's pretty good. If you do that in a lifetime, you did good. But you did that and then just kept going. Yeah, but at the same time, I was learning magic and you were really burning your house down

with the biggest wax candle. That's the backstory. And the lead scientist on this was Kip Thorne. Yeah. Kip Thorne. People who read movie credits will recognize Kip Thorne as one of the co-executive producers of the film Interstellar. Nice.

That's how you knew if there's going to be any black holes in it, they're going to get it right. Yes. Okay? You don't have to double check that one. He's got it. Yeah. I love that.

All right. Give me some more. All right. Well, some more. All right. Well, you were talking about the fabric of space. So it makes sense to bring this question up because Matt D wrote, greetings, Dr. Tyson. I'm Matt from Oklahoma and have a question about the fabric of space. In all caps, what is it? You tear it like cloth fiber and sew it back together.

Take it easy, Matt. Okay. All right. So he has issues with the word fabric. Maybe. I mean, it sounds like he thinks it is a fabric. Well, it does stretch Lycra style, right? So the universe stretches, but we don't know how much longer it will continue to stretch. Oh, it's like my pants. It snaps. Been there, done that. I think we did a whole episode or a whole section of an episode

on the future of the universe. One of the possible futures is it will expand so rapidly that the fabric of the universe cannot keep up with it and it will rip. And it's called the Big Rip. And I'm terrified by this because I finally grew accustomed

to the stretching of space and time, whatever even that means, right? Now you're going to tell me it's stretching and it's going to rip? Oh my gosh. Do we know where it's going to rip? Are we near the rip site? Do we need to move a little bit?

Put some priest stitches in it to keep it going? It would rip at its very core. All places within the fabric would just disassemble. Rip and fabric go together as two words. But before we used the word rip in the fabric, we spoke of space as a rubber sheet that stretches. Maybe it can stretch forever. We don't know. a rubber sheet that stretches. And maybe it can stretch forever. We don't know.

We just don't know. So now the specifics of the question was what? It just said, what is it? What is the fabric? All we can say is space behaves as though it is a stretchy substance. Pick any word you want to give it. Right. Maybe we should have called it the lycra of the universe.

Sure. Or the neoprene. The neoprene. Right. I don't know. Call it anything, but we try to find an analogy that can make it more understandable to you,

to anyone, to ourselves. So fabric of the universe seems to fit the bill very well, right on up to the rip. Right. So that's why. And that's when everything in the universe disassembles, including us?

Oh, you're made of things in the universe. So yeah. I was trying to be optimistic. Yeah, all the electrons, protons, and neutrons, they're not all going to break apart, but you'll be intact. Okay. Exactly.

That'll be. Do I feel it? Yeah. I'm terrified by it. If it happens at all, it'll happen in 22 billion years. Oh, so we're okay. We're okay.

No, I got it on my calendar. So fabric is metaphor, but it's a very apt metaphor for what the universe is because the universe can curve and curve back on itself it can stretch if you're not happy with fabric come up with another term but i think we're good that's pretty good all right all right this question comes from geezer windbag greetings dr tyson i'm curious why we say the universe exploded in the big bang it seems to me more likely that the singularity

expanded and fragmented and the universe we see is still all within the singularity an observer outside the original singularity would still see a singularity though from our perspective the universe is incredibly huge thoughts okay so a couple of things if he doesn't like the word explosion,

I'm okay with that because the singularity that birthed the universe was the rapid stretching of space-time. There we go. See what I did there? So the rapid stretching, you can say, was there an explosion? You know what an explosion is?

It is a rapidly moving shockwave within a medium. That's what blows out windows and blows down doors. It's a shockwave moving through the air. Well, the Big Bang is not a thing moving through something else. It is the expansion of space and time. So it's more accurate to say it's the Big Stretch rather than the Big Bang. more accurate to say it's the big stretch rather than the big bang the big bang was used pejoratively by we're now going back 70 years by an opponent of the big bang who couldn't imagine the universe would begin this way he wanted the universe to be in a steady state at all times and he's and so he

used the term big bang as an insult to the ideas that people were having. He came and he said, you know what? This theory is a big stretch. And they're like, you have no idea how right you are. That's exactly right. This is a stretch. That's it. So yeah, it's metaphor, but we're good with it.

All right, cool. Well, thank you, Geezer Winback. No, no, but he asked something else about it. Well, he said, is it more likely that the singularity expanded and fragmented and the universe we see is still all within the singularity we are no longer the singularity so anyone observing us will not say they look like a singularity uh the interesting question is if you look at the math of our universe out to the horizon the density of matter within it, the size of the horizon,

if you run the math, we have all the same properties of an authentic black hole. And black holes have singularities in their center. So are we some Mondo black hole? Is there a point where the similarities end? We don't know.

We could all be in a black hole? Yes. Yes. Yes. I have a book on my shelf that describes the new space-time that opens up after you fall into a black hole. Time changes for you. It ticks more slowly relative to everybody outside the black hole. So as you fall in, you will see the entire future history of the universe unfold before your very eyes, and a new space-time continuum open up. That sounds awesome. Minus the being ripped apart.

Minus the being ripped apart part. Yeah. So if the black hole's big enough, the tidal forces won't rip you apart. You can survive the fall. Oh, that's cool. Yeah, yeah. Yeah, it's good. It kind of feels like a way to go.

I totally want to go that way. You know, rather than get hit by a bus or laid up in the hospital, launch me into a black hole. I'll give all my reports until I can't. All right, so we have Eliezer Vega.

Hello, Dr. Tyson. This is Eliezer from Puerto Rico. Puerto Rico. I love that place. Is that your best way you could pronounce it? Puerto Rico. All right. I'll give youiezer from Puerto Rico. Puerto Rico. I love that place. Is that your best way you could pronounce it? Puerto Rico. All right.

I give you a B plus. All right. Puerto Rico. I have a last gap to fill with gravity. If gravity is the effect of the mass bending space, then why when a star goes supernova, space still bent for a black hole to form instead of immediately unbending,

it is as matter is blown apart, or better said, what makes space remember what was there before? So when It is as matter is blown apart, or better said, what makes space remember what was there before so when it blows and matter is dispersed, space won't recover back but stay bent as a black hole.

Did you get all of that? Wow. Stars above a certain mass, when they die, will go as supernova and they'll leave behind a neutron star. Stars of even higher mass,

we're not entirely certain of the boundary of this, but stars of a higher mass can go supernova and make a black hole. Stars of even higher mass, the supernova never gets out. Black hole all the way. So only in that last case is all the mass of the entire system part of the black hole. And the space-time curvature at the end was the same as it was in the beginning. Whereas the one where some gets blown out and others become a black hole, yeah, that black hole does not have the full gravity that the whole system had before because half of it got blown away. It's that simple.

So he's right to think about this, but the answer is not that deep. That's pretty good. Matthew Jury wrote, hello everyone. How can a gravitational singularity exist if infinite curvature means infinite time? We do not have a good way to talk about the singularity. Would you say the jury is out? What I would say is that's why we have string theorists to bridge the gap between quantum physics and general relativity, one, the theory of the small, the other, the theory of the large. But at the beginning of the universe, the large was small.

Whole universes were operating in the quantum realm. I've seen Ant-Man. I get it. Yeah, yeah. There you go. Okay. So if that's the case, what's happening at the singularity? Because you don't get singularities in quantum physics.

You get it in general relativity. So that's where it's been said the singularity is where God divides by zero. Have you divided by zero lately? Error. Yes. Yes. Yes. Error.

I do a magic trick where I have people put stuff into a calculator, and if they divide by zero, there's no magic trick because there's just an error. Yes. Yes. Yes. Error. I do a magic trick where I have people put stuff into a calculator and if they divide by zero, there's no magic trick because there's just an error. So I very much, it's very salient for me. Wow. Okay. To avoid the divide by zero. If you divide by zero, it's an error. It's undefined and we don't know what to do there. Yet we know these two theories work in their own realm their own regimes the small and the large you bring them together the shotgun wedding that won't necessarily work as you had planned so we got top people working on it so no we can't tell you what's happening inside the singularity all right remains a mystery yes Yogi's Jog

wrote, hello to my personal astrophysicist. If someone keeps traveling back and forth at plank length distance, does it mean that it's traveling eternally? He did put a parenthetical, which says an idea slash attempt to say that the particles don't come in and out of existence. They're just traveling eternally

at Planck length distances and four forces hits them at the right time to let them exist in this universe. Okay. Yeah, I don't know what he's talking about. I can tell you this. A Planck length is the smallest unit of length that we can measure.

It's very, very small. It almost doesn't make sense. It's not the size. It's what you do with it. It turns out in quantum physics, everything is in motion. Everything vibrates at all times. Exhausting.

To say you have something moving back and forth across a plank length, all matter is doing that at all times because everything is always in motion. Always. So to say let's do it at a plank length plank length and his time at infinity i don't know how the connecting plank length and infinity time in that question but everything is always in motion at all times and it has nothing to do with measuring time at infinity gotcha all right right. Especially in this city, huh? New York City?

All right, I'm fired. Okay. This is from Vinay Kashyap. He says, hello. What's your first name? Vinay. Vinay, okay. It's how I would say Vinay if I was being fancy.

Okay, Vinay. Vinay. He's, hello, this is Vinay from India. I was just wondering why black holes can't just be dark matter. There seems to be a lot of them. They are massive and seem to have more gravity. Most importantly, we can't see them.

Let's list the dark matter candidates. Would there be dark clouds? Could there be vagabond planets that are not illuminated by a host star that got ejected into the galaxy? Could it be black holes? It turns out the physics of the early universe limits how much ordinary matter there can be. Black holes count as ordinary matter because you make them from ordinary matter.

It limits it. There's a delicate set of knobs that we're turning in the early universe to understand what we what the universe was and what it became and so these knobs are they're fascinating because some combinations of knobs don't work at all you don't get a universe or you get a universe that's very different from what we have. So the problem with dark matter is it doesn't interact with ordinary matter in any way other than by gravity. And so if you look at what it does in the universe during the early universe, it can't be regular matter. Otherwise, we'd have a universe completely different from what we have. And black holes are made of ordinary matter. It has to be something completely exotic beyond the measurements we've

made of electrons, protons, neutrons, atoms, molecules, solids, biology, chemistry, physics, psychology. Everything that we know and love falls outside of what dark matter can be. protons, neutrons, atoms, molecules, solids, biology, chemistry, physics, psychology, everything that we know and love falls outside of what dark matter can be. So let's say we have very good theoretical evidence, theoretical support for why dark matter can't be black holed. All right, we have Mike Muhammad Kake. I assume it's pronounced as a bird would. No.

Kake. Greetings, Dr. Tyson. Mike Kake from Berlin, Germany. While it's well known that most of Earth's energy originates from the sun, I'm curious about the source of tidal energy.

Can it be traced back to the sun or does it stem from a different origin? Is it possible that tidal energy has multiple sources? I love that because when we talk about green energy, we're talking about renewable energy.

And if you could turn plants into gasoline, which we do with ethanol, which is the one from corn. My wife is from Nebraska, so she's going to be very disappointed if I don't know the corn thing. She's going to kick your ass. Yeah, I think ethanol, we get that from corn. And corn is a renewable resource. It's not fossil fuels where you take it out, you can't wait for new fossils to form. That's not how that works. So that's why one is renewable and one isn't. By the way,

do you know the original energy source of fossil fuels? The sun. Oh, there you go. Oh, you were going to say dinosaurs? I was going to say dinosaurs. It was mostly plant life at the time, but where does a plant get its energy? From the sun. The sun. Put us into this. So all fossil fuels

is energy from sunlight. It's just not renewable because it's a one-time use. So all plants get their energy, all surface plants get their energy from the sun. You eat plants, you get energy from that. If you eat meat, you eat some animal that

ate an animal or ate plants. And so the tracking is back to the sun. Now here's something deep. What generally do fish eat? I was going to say fish food. That was what came to mind first. Fish food, of course.

They eat, well, do they eat stuff in the ocean? Algae and stuff? Eat other fish. Yeah, but then who eat? Well, I'm getting there. Good one, of course. They eat... Do they eat stuff in the ocean? Algae and stuff? Eat other fish. Yeah, but then who... Well, I'm getting there. Good one. This is where I'm headed. This has turned us all the way down. But it can't go all

the way down. This is why you can't... There's no such thing as a stable cannibal society. It's not stable. Amongst other reasons. I'm sorry. I'm not ranking the reasons.

I'm just offering reasons. Because you can't just keep eating each other. Right. Because you will run out of people. Sure.

But you can say, well, why don't we reproduce faster than we eat? That's not possible because if you're a fully nourished human being, you have to eat at least a whole other human being. Right. Because you are a human being, right? You have to eat at least that. And if you just run the numbers, you can never have a stable thing

where you're only eating other things that are being born within it. At some point, you need a source from the outside. So the big fish eats the littler fish, eats the littler fish, eats the littler fish. This goes all the way down until you get the plankton. So the fish start eating all the way down. Right. And then you get to some point where, if that's all that was happening, the ocean would just eat itself and there'd be no living things, no fishes left in the ocean.

Something has to come in from the outside. Somebody's got to deliver the groceries. SpongeBob. He has a pineapple under the sea. You got it. You got it. You got it. His pineapple is actually in the sea. Yeah, that's true.

We need to correct that. Okay, I'm just saying. I don't mean to get all technical on SpongeBob. But you finally reached the level of plankton. SpongeBob. Nailed it. And there are two categories of plankton. Okay.

One of them eats other life forms in the ocean. The other for nourishment, the other gets its energy from the sun and they all live right at the surface where they can get sunlight. That is the base of the food chain of the ocean. The phytoplankton. If you kill them off, you will systematically render extinct

every other fish in the ocean that eats other fish. Now, there might be some fish that eat, like the kelp and seaweed and things. There might be some. But where does kelp get its energy from? The sun. Right. Okay, so the sun is the ultimate source of all energy

in the typical fishes that we think of in the ocean. However, the ocean in certain parts is open to what's below it. What's below the ocean? Well, you get through the crust, and below the crust is the mantle, and in the mantle is magma. Beneath that Godzilla, according to the films. Oh, is that right? Okay, the mantle is magma. Beneath that Godzilla,

according to the films. Oh, is that right? Okay, I did not know that. The hollow earth. Yes. Thank you for enriching this scientific discussion here. So I keep thinking

this should be magma PI. That would be a fun sort of... A really cool mustache that is past the point of boiling. So below the crust, we get the mantle, and within the mantle is magma. Okay, molten rock.

Earth has retained still a considerable amount of heat from when it formed. And that heat wants to get out. And it gets out through volcanoes, through crevasses in the bottom of the ocean. The mid-ocean ridge is just such a place. One of these ridges goes through Iceland, the country.

Iceland is growing because the continental plates are separating. Magma gurgles up, hardens, and there's more Iceland. That's a very good plan for the future. We have discovered life forms that thrive on geochemical energy enabled by these hot vents at the bottom of the ocean. In apocalyptic Earth, even if the sun burns out, if someone plucked the sun out of the solar system and we fly off at a tangent into interstellar space, we will all die rapidly. But the life forms at the bottom of the ocean that are warm from the magma oozing up through the vents, they'll be just fine. They will survive the death of Earth's surface.

So that's another source of energy. By the way, geothermal energy, because Iceland is sitting on a, at the separation of two continental plates, they're almost entirely geothermally driven. Their carbon footprint is minuscule. They have so much energy, they send water under their streets so that it never gets icy in the winter.

We don't need snow plows. Just heat the streets. So that's another source of, it's renewable in the sense that it's like a near infinite supply of earth energy available to us, all right? Yes, it would one day run out, but not really because we had something to do with it. All right, it's the volcanoes go. Have you seen earth get angry? All right, it's got a lot to kill us in the future.

So that's another source of energy. So these are different ways. So another way is a hydroelectric. Okay, so that's gonna source of energy. So these are different ways. So another way is hydroelectric. Okay, so that's to be dams. You have water up here and that is a certain height that it can fall, gaining kinetic energy. Sure. And it comes through a turbine that then drives a generator that makes electricity. So what's that based on?

How did the water get up to the top of the dam? The sun evaporated it from the ocean, brought it up to a cloud. The cloud moved over the land, rained on the land. It brought the water up to the upper levels. That's solar power. Hydroelectric is solar power. How about wind? Why does air move horizontally on the earth

you know what ogden nash said he said wind is caused by trees waving their branches and i thought that was good like how would you know it wasn't that i feel like we do know that i feel like we're about to lead into the fact that that can't be. Yeah, it was just a clever, kind of fun, stupid observation. The only thing I know about Nash is he has a great equilibrium. Oh, that's the

mathematician. Different Nash. That's a totally different Nash. And then the founder of Nashville. Oh, I don't know who that would be. I assume he's a Nash. So, wind comes from the unequal heating of Earth's surface that creates air that rises, air that falls, and that also creates pressure differences that'll move air horizontally as well as up and down.

So wind energy is solar energy. Set up a solar panel. What do we call that energy? Solar. Solar! That's taking out the middleman and now you have solar power. So all of these are solar power

that is in principle renewable until the sun runs out of energy. All right. How about tides? Tides slosh back and forth. Love it. Well, we associate, commonly associate tides with the moon.

Sure. So the moon tides have nothing to do with the sun. So if you have a tidal thing that drifts with it and generates energy, it's also renewable because you're always going to have tides, but it's not traceable to the sun. However, one third of the tides you measure comes from the sun. How's it doing that? Well, the full name is loony solar tides,

loony moon, solar sun, loony solar tides. The tides we all experience are loony solar tides. And the moon is like two thirds of it. And the sun is one third at all times, at all times. If you're using tides, some of that is the sun. Most of it is the moon. If you're using tides, some of that is the sun. Most of it is the moon. And so there you have it. That's the difference from all of this. But if you pulled fossils out of the ground, you're not renewing that.

And when you run out of fossils, you're done. Oh, by the way, there's thermonuclear fusion. We haven't harnessed it yet. We know how to create it. They're called bombs. But when you harness it, That's a lot of energy. That's a lot of energy.

You can create a power plant and that's fusing hydrogen together to make helium. The sun does that every day. So we just be mimicking the sun on earth. It's the nuclear fission that has dirty byproducts. And that's what the original atom bombs were made of, fission bombs. But nuclear fusion, that's the holy grail. But here's,

I saw a bumper sticker once that said, no nukes. It was a very green, sort of progressive, left-leaning bumper sticker, no nukes. But the O in the no was a sun. Which is the ultimate nuclear weapon.

The ultimate nuclear furnace is the sun. Okay? If you had no nukes, you wouldn't be here. All right. Well, you know what they mean, of course. They don't want nuclear energy. They want solar energy. But solar energy is nuclear.

I think at the time I saw this bumper sticker, it was still in the Cold War. So maybe they were talking about the nuclear arsenals. Sure. For sure. But the fact that they had a sun there, it still tells me that they were thinking of generating power. Sure.

Yeah, use solar power rather than nuclear power. But one other quick source of energy, because the big problem with solar energy is how do you store it? If you want to use it at night, how do you use solar energy? No, you can't. Okay, tides still move in and out at night. That works. Hyd? If you want to use it at night, how do you use solar energy? Now you can't. Okay, tides still move in and out at night. That works. Hydroelectric, you can use that at night.

That all still works. But how do you use solar panels? So there's talk now of using solar panels to lift heavy weights up a hillside to turn photons into potential energy that then becomes kinetic later. So your storage battery becomes solar power lifting all these weights up into the air.

So it's a successful way to store the solar energy that you had earlier, and then you could draw from it at any time of day or night. That's amazing. It's very clever, yeah. There's a lot of balls at the top of hills, and like, don't touch them. This is powering the very clever. Yeah. There's a lot of balls at the top of hills. I'm like, don't touch them. This is powering the whole city.

Yeah. So anyhow, there you have it. That's everything that was not even asked in that question answered about where energy comes from. And I like dirty byproducts. I'm going to make that my next comedy album. It's going to be called Dirty Byproducts. Dirty Byproducts.

All right. We have one more question. We've got time for one more. Go give it to me. This is from Cicero Artifon. Hey, smart people. That's a cool name. You've got to admit that.

That's a really cool name. That's like a sci-fi hero name. I want that name, Cicero Artifon. Yeah, he's the hero of like a Blade Runner kind of trilogy, Cicero Artifon, where he's like the president in the Hunger Games. You need an evil variant of this. Yeah, exactly. He can go either way.

So hopefully this Cicero is leading towards good. But he said, hey, smart people, Cicero from Toronto, Canada. He's from Canada, so probably good people. Neil mentioned once that the element osmium, 76, is heavier than gold, 79. How can that be possible? Don't the elements have an increase of mass the lower they are on the table? He's slightly misremembering what I said. Oh, no.

That's okay. So as you go up the periodic table, the elements become more and more massive. Right. More and more massive. No doubt about it. You're packing more protons into the nucleus. He mentioned how many protons were in osmium. I forgot he said 76. I'll believe him. Gold was

79, was it? Okay. That's what he said, yeah. Okay, uranium is 92. These are bigger, heavier atoms all the way. That's not what distinguishes osmium. If you create a lump of these materials, a lump of osmium, a lump of gold, a lump of them, how close together will the atoms pack in this lump that you have created? That's the question.

It turns out, given the properties of atoms and the periodic table and the quantum physics of nuclei and energy levels and atoms, you can pack osmium atoms closer together than all the other kinds of atoms, closer together than all the other kinds of atoms, thereby making the densest element, not the heaviest element, the densest element, because now they're packed in close together. So osmium would make the world's best paperweight. I mean, it could make a wedding ring. How come we don't use it in place of any of these precious metals?

Why would you want it to be heavier? We heavier but we like gold you remember that you're married i'd be like oh my god i can never forget i can barely lift my hand it's a ball and chain analogy here's the osmium ball you're going to carry around so uh so that's the that's the only difference and just to quantify that how dense these things are, a cubic foot of gold, oh my gosh. It's like, you know, gold has two and a half times the density of iron. That's gold.

And osmium tops that. And osmium, I think, may be used in the tips of some fountain pens. Because it has to be very hard. Because you're pressing on it. There's a lot of pressure there. So it has its utilities. Sure. But paperweights are not among them.

Right. So that's why. We're talking about the density of an aggregate of those atoms. Not the weight of an atom itself. Nice. Well, thank you, Cicero. I think that's all the time we have. Amazing.

Well, it's great to have you back. Thank you. It's been so great to be here. It's very good. I really appreciate it. Yeah, yeah. So how do we find you in the city? They can find me on social media

at Harrison Comedy on Instagram. Oh, Harrison Comedy? Harrison Comedy. Good, uh-huh. And HarrisonGreenbaum.com is my website. Okay, excellent. And you perform? I perform every night.

I'm all over. I have my off-Broadway comedy and magic show on Saturdays at Asylum NYC. when you're on Broadway. I don't need this. No, no, it's great.

Well, if enough people buy tickets, maybe. So it's a gig. No, it's great because you do magic and comedy and we love you here. We'll try to get you back.

I would love that. Thank you so much. All right, this has been Star Talk, a Cosmic Queries grab bag edition with Harrison Greenbaum Thank you so much. All right. This has been Star Talk, Cosmic Queries Grab Bag Edition with Harrison Greenbaum. That's me.

All right. We'll see you next time. As always, keep looking up.