Cosmic Queries: A Stellar Smorgasbord

Astrophysicists Neil Tyson and Charles Liu answer a feast of fan-submitted questions, ranging from asteroid mining to the heat death of the universe, selected by co-host Eugene Mirman. Plus a new “How Tweet It Is” segment with Neil and Bill Nye.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Neil deGrasse Tyson?

  Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:21Neil deGrasse Tyson?

  I'm your host Neil deGrasse Tyson, your personal astrophysicist, and this is StarTalk. This is Cosmic Queries Edition.

• 0:32Eugene Mirman?

  Yeah.

• 0:32Neil deGrasse Tyson?

  Cosmic Queries. And I'm ambivalent whether I prefer Cosmic Queries that is a single topic or whether it's potpourri. This one is potpourri, which is easier to stump me, and if we're gonna do a potpourri, I don't want to do it alone.

• 0:46Eugene Mirman?

  Okay.

• 0:46Neil deGrasse Tyson?

  But I know who to call.

• 0:48Eugene Mirman?

  Mm-hmm.

• 0:49Neil deGrasse Tyson?

  I've got like a bat signal, and my friend and colleague, Charles Liu, Charles.

• 0:54Charles Liu?

  Hi Neil.

• 0:56Neil deGrasse Tyson?

  There you go.

• 0:56Charles Liu?

  Or shall I say Robin?

• 0:58Neil deGrasse Tyson?

  So, this is not your first time on StarTalk. It's your nth time on StarTalk, as we say. That means you've lost count, and it's some large number algebraically. And so Eugene, we have questions that come to us over our Facebook pages and our Twitter and other outlets, and sometimes we can gather them into one topic, but other times we can't. And it's a potpourri. And so I have not seen the questions. Eugene is gonna read them, and you and I are gonna try to answer them. That's what this is. And if we can't, we just say we have no clue, go on to the next one.

• 1:35Eugene Mirman?

  Then I will answer it. If you don't know, I probably know it.

• 1:38Neil deGrasse Tyson?

  And Charles, and I might not even agree on an answer. That would be kinda fun, we'll see.

• 1:42Charles Liu?

  That would be awesome.

• 1:43Eugene Mirman?

  Scientists ever disagree? Just kidding.

• 1:45Neil deGrasse Tyson?

  So let's do this, okay?

• 1:47Eugene Mirman?

  Alright.

• 1:48Neil deGrasse Tyson?

  What do you have Eugene?

• 1:49Eugene Mirman?

  Well, this is from Patreon.

• 1:51Neil deGrasse Tyson?

  By the way, just quick, our Patreon supporters are one of the categories of Patreon support, gets your question asked first.

• 2:02Eugene Mirman?

  Yeah.

• 2:03Neil deGrasse Tyson?

  So I don't know what that's worth to you in supporting StarTalk, but that's what's going on there. And the reason why I have Charles is Charles knows so much about random stuff.

• 2:14Neil deGrasse Tyson?

  Spooky amounts of random stuff.

• 2:17Charles Liu?

  Is that good or bad, Neil?

• 2:19Neil deGrasse Tyson?

  It's it's both.

• 2:21Eugene Mirman?

  We'll find out what you know, and then I'll let you know if it's good or bad.

• 2:24Neil deGrasse Tyson?

  All right, there you go. Eugene, you'll you're the adjudicator. Go.

• 2:27Eugene Mirman?

  Okay, uh, Keilia Silves asks, oh, and Jeremy Kaiser together from Minnesota, they ask.

• 2:33Neil deGrasse Tyson?

  They are Patreon supporters. Thank you for your support.

• 2:35Eugene Mirman?

  Thank you. Will asteroid mining ever be financially viable from a purely business standpoint?

• 2:42Neil deGrasse Tyson?

  Ooh, let me answer that, and then Chuck might have a have a have a have a additive to that. I did not believe that it could be financially lucrative because if there's gold on an asteroid, then you go get it. What did it cost you to get the gold? Probably more than the whatever thousand dollars an ounce it's going for now. So what's the point? Until I spoke with asteroid mining people who said in the in the future, we're going to have operations in space, manufacturing in space on the moon, on Mars, at at at the gravitational balance points, the Lagrangian points, and they will need raw materials. And so you would go mine the asteroid, take the raw materials to these other places,

• 3:26Neil deGrasse Tyson?

  and then you don't have to go in and out of Earth's atmosphere in our gravitational well. Is that about where you said on this, Charles?

• 3:32Charles Liu?

  I think so. So within, say, thirty or forty years, it won't be feasible. But as soon as we get manufacturing in space, it will start becoming economically more feasible.

• 3:42Eugene Mirman?

  Is there an amount of platinum that an asteroid could have that would make sense to bring it back to Earth?

• 3:47Neil deGrasse Tyson?

  So I thought about this, and let's say there is such an amount, and then you bring it back to the Earth. What does it do to the platinum market? It completely drops the price of platinum. Okay, so now watch. You say, well, that's bad. You might say, however, if the price of platinum drops or anything that's previously cherished and in rare quantities. Creative other things you can do with that material start to gurgle up in the, on the landscape of innovation.

• 4:15Charles Liu?

  Right.

• 4:15Neil deGrasse Tyson?

  And not that I can think of one now, but Charles, uh, what's, what's an example? When we finally, oh, aluminum. When it was first extracted from bauxite.

• 4:26Charles Liu?

  Yes.

• 4:26Neil deGrasse Tyson?

  It was a cherished metal. It was light. It, it, people were replacing silver with it. It was, you wore aluminum as a, as a, cause to show you were wealthy.

• 4:36Charles Liu?

  That's right.

• 4:36Neil deGrasse Tyson?

  And then once that process, it's not mining an asteroid, but it's the same idea. Once that process became more and more efficient and cheaper, and now we throw away aluminum.

• 4:45Charles Liu?

  We wrap our food in aluminum.

• 4:46Neil deGrasse Tyson?

  We wrap up an unthinkable thing back when they first extracted it from bauxite.

• 4:51Charles Liu?

  That's right. So then.

• 4:52Neil deGrasse Tyson?

  I don't think it's necessarily a bad thing to completely collapse the market.

• 4:56Charles Liu?

  Right.

• 4:56Neil deGrasse Tyson?

  Of a metal that is previously rare.

• 4:57Charles Liu?

  What if it was a metal that has not yet been discovered? That would be the only thing that might be valuable enough to bring back.

• 5:02Neil deGrasse Tyson?

  I think we, well, Charles, correct me if I'm wrong, the periodic table of elements is complete at this point.

• 5:07Charles Liu?

  Uh, well, up to about a hundred and fourteen on the atomic number scale. Yeah. So what about a hundred fifteen? Is that not possible? Uh, that has a half-life that's so short that it would disintegrate. It wouldn't survive in an asteroid. But what you might be getting at Eugene is the issue of having rare earths, you know, little tiny percentages of things that we don't normally use a lot right now. But say we put in semiconductors to increase the ability of our cell phones to run micro transistors and things like that.

• 5:36Neil deGrasse Tyson?

  Yeah. Cause just cause they're rare on earth, doesn't mean they're rare somewhere else. Right?

• 5:39Charles Liu?

  Exactly. They're rare earth, not rare asteroid.

• 5:41Neil deGrasse Tyson?

  Not rare asteroid.

• 5:42Charles Liu?

  So the answer is not a particularly great business model if, right now.

• 5:46Neil deGrasse Tyson?

  Yeah. Except it could completely transform civilization.

• 5:49Charles Liu?

  Yes.

• 5:49Neil deGrasse Tyson?

  In the utility of one element versus another.

• 5:52Charles Liu?

  Once you're in space, it's easier to get more gold in space.

• 5:55Neil deGrasse Tyson?

  Keep going.

• 5:56Charles Liu?

  Yeah. Um, all right. So Megan Fischel, also a Patreon, uh, patron asks.

• 6:02Eugene Mirman?

  A few of my astrology inclined friends claim the reason. No. I know, Graeme, the reason my iPhone has been a bit dodgy recently is that Mercury is in retrograde. Is there any validity to their claim?

• 6:16Neil deGrasse Tyson?

  Charles?

• 6:17Charles Liu?

  No.

• 6:18Neil deGrasse Tyson?

  Okay.

• 6:20Eugene Mirman?

  Sorry.

• 6:20Charles Liu?

  Wow. I'll say this, Mercury does go in retrograde. But when it does, we can't see it because it's actually in the direction of the sky that the sun is. So we wouldn't be able to detect it anyway in any visible format. And so in terms of what's happened to the cellphone or anything like that, uh, any kind of effect is completely non-existent. Now, it's interesting that you say this though, because I was getting on a bus once, uh, in New York's Port Authority about 10 years ago.

• 6:48Neil deGrasse Tyson?

  And the bus went retrograde.

• 6:49Charles Liu?

  Barely, yeah, somebody barely got on the bus, was like dashing on and sat next to me and said, "Ah, I know I was late because Mercury is in retrograde. I just knew it. I just knew it." So, maybe, you know, collective belief creates a fantasy that might be propagated to this day in modern cellphones. Who knows?

• 7:09Eugene Mirman?

  Yeah, too bad they didn't leave 15 minutes earlier.

• 7:12Neil deGrasse Tyson?

  And another point about the concept of retrograde, the very word retrograde traces from a time when we had no notion that Earth was in motion around the sun. And so people actually believed that Mercury would be in motion in space, slow down, stop, reverse itself, and then pick up its previous motion slightly after that, as though that was a physical thing happening to Mercury.

• 7:38Charles Liu?

  Mm-hmm.

• 7:38Neil deGrasse Tyson?

  And retrograde, all it is, is what is your point of view on objects that are all in harmonious orbit, moving around the sun? And so, so, and I thought when you talked about the person miss- almost missing their bus, I thought you would say when you're on a bus looking out the window, see another bus, and you see that bus go backwards, and half the time you see that, you say you're actually going forwards.

• 8:00Charles Liu?

  Yeah.

• 8:00Neil deGrasse Tyson?

  Right? So you're gonna say, "Oh, it's backward bus." No, you're the one in movement, not that. And so a lot of that language and a lot of that cultural, uh, uh, misappropriation of cosmic phenomena claim about because we did not know that we were all moving around the sun. It's that simple.

• 8:17Charles Liu?

  Okay.

• 8:18Neil deGrasse Tyson?

  Okay, next.

• 8:20Eugene Mirman?

  Uh, Ben Yeast from Facebook asks, "I read that if our universe turns out to work a certain way, it's possible for black holes to rotate so rapidly they prevent an event horizon from forming. If we do live in a universe where the, these naked singularities are possible, what evidence of their existence would we look for?"

• 8:40Neil deGrasse Tyson?

  Ooh, Charles, I gotta...

• 8:42Charles Liu?

  Well...

• 8:43Neil deGrasse Tyson?

  That's a hard one, Charles, take it.

• 8:45Charles Liu?

  Thanks a lot. Uh, he might be referring to something called a maximally spinning curved black hole.

• 8:53Eugene Mirman?

  Mm-hmm.

• 8:54Charles Liu?

  And that is theoretically possible, although it wouldn't last as long as a typical black hole that's spinning at a slower speed, just because it wouldn't stay in equilibrium very long.

• 9:04Eugene Mirman?

  What's that length of time we're talking about, like milliseconds or years or hours?

• 9:10Charles Liu?

  Well, you know, I have to go back and check my general relativity notes from graduate school. I'm sorry.

• 9:16Neil deGrasse Tyson?

  Me too. Okay, you too. No, no, Charles, this is, this is cosmic queries. You can say, "I don't know."

• 9:23Charles Liu?

  I don't know.

• 9:24Neil deGrasse Tyson?

  Or, "I once knew, I don't know anymore. I'll get back to you, call me in the morning." So, we're, I mean, we don't know, we'll just go on to the next question. That's part of how this, that's part of how we roll here.

• 9:34Charles Liu?

  No, that's fair. Okay. Now, naked singularities, though, if you're looking for them, you're kind of looking for them the same way as you look for any other black hole, through gravitational lensing. You want to see what they have done to the view of space and objects in space behind them, and by the patterns that they create, you can deduce whether they are maximally spinning, or whether they're static, or if they're supermassive, or any combination they're at.

• 9:59Neil deGrasse Tyson?

  So, once again, the power of inference, once we have good data on what they're, on what other things are doing in their vicinity.

• 10:05Charles Liu?

  Yes.

• 10:06Neil deGrasse Tyson?

  Yeah. Or light paths that go past them.

• 10:08Charles Liu?

  Mm-hmm.

• 10:09Neil deGrasse Tyson?

  Okay. All right, what else you got?

• 10:10Eugene Mirman?

  Uh, Dick Craig from Facebook, he wants to know, "Can the mass of the Earth change, and wouldn't this slow or speed up our time?"

• 10:19Neil deGrasse Tyson?

  Well, the mass of Earth is changing every day. We're we're gaining several hundred tons of meteor dust a day.

• 10:27Eugene Mirman?

  Oh, really?

• 10:27Neil deGrasse Tyson?

  Yes. But Charles, aren't we also losing some air to the uh, or isn't?

• 10:32Charles Liu?

  Yes, a small amount going out. Uh, the mass coming in is still more than the mass going out, though, on a given day. So we are growing a little more massive every day.

• 10:40Neil deGrasse Tyson?

  So the mass going out is we're losing some of our upper layer of our atmosphere.

• 10:44Charles Liu?

  Yes.

• 10:44Neil deGrasse Tyson?

  Correct. Okay. So, but 300 tons sounds like a lot, not compared to the mass of the Earth. And I tried to run some numbers on this, Charles.

• 10:53Charles Liu?

  Oh.

• 10:54Neil deGrasse Tyson?

  And I and I got something like, uh, a gnat flying full speed ahead into the side of an elephant was some huge factor greater than what Earth would feel if it got hit by a comet slamming into its side. And so you don't see elephants concerning themselves with their mass by how many gnats land on its back.

• 11:23Eugene Mirman?

  Yeah, but if the elephants became bigger every day from gnats, you know, given a billion years, it's a little bit bigger.

• 11:30Neil deGrasse Tyson?

  Yeah, okay. All right. So let's answer that question, Charles. So

• 11:33Charles Liu?

  Okay.

• 11:34Neil deGrasse Tyson?

  Make the Earth a little more massive. So what?

• 11:36Charles Liu?

  All right. Well, Earth is six times 10 to the 21 tons, right? If you add 300 tons a day, that's what? A million tons a year? That would still take longer than the age of the universe to double Earth's mass. So we would have to wait a very, very, very long time to see any gravitational effects.

• 12:04Neil deGrasse Tyson?

  Any meaningful gravitational effect.

• 12:06Charles Liu?

  Any meaningful gravitational effect.

• 12:07Eugene Mirman?

  I have time.

• 12:08Neil deGrasse Tyson?

  Okay.

• 12:10Neil deGrasse Tyson?

  And if Earth's mass go up, then we all start weighing a little bit more.

• 12:15Charles Liu?

  Yes, right. But there's no effect in our orbit, really, because the way that Newton's law of gravity works, the speed of our orbit around the sun would not change unless appreciably or measurably, unless we started to approach the mass of the sun. And Earth is less than one three hundred thousandth the mass of the sun. So that's not going to happen for even longer times than the age of the universe.

• 12:40Neil deGrasse Tyson?

  And by the way, what Charles is doing here, we spend many, many years in solving problems, thinking about how the universe works. By recognizing this quantity is large, that one is small, here we can ignore the small quantity. The most, or this quantity divides away. And this, this, this, these are tactics we have to gain some sense of how the universe works without worrying about it on such a level of detail that it becomes a distraction.

• 13:06Charles Liu?

  Mm-hmm. Right. Like, you know, just quickly in my head, I would say your analogy of gnat on an elephant is very close to the actual effect. You can imagine if Mount Everest were hit by a snowball every day, how long would it take before Mount Everest would actually be appreciably more massive or more large, say, than it is now? And the answer is a very, very, very long time.

• 13:30Eugene Mirman?

  Yeah.

• 13:30Neil deGrasse Tyson?

  Okay.

• 13:31Charles Liu?

  Okay.

• 13:31Neil deGrasse Tyson?

  What do you got?

• 13:32Eugene Mirman?

  Uh, Michael Vaca from Facebook, he asks, "I'm concerned Snowden is right about strong encryption making alien signals look like background noise. Are there other ways to sense life remotely?" I don't know about what Snowden...

• 13:46Neil deGrasse Tyson?

  So we interviewed Ed Snowden for StarTalk, and we are proud on StarTalk to have brought him to Twitter. And so I had the very first conversation with him on Twitter that he promised he would do on air with us. And so in that conversation with him, we talked about encryption. And Charles, there's an interesting point, I don't know if you caught that episode. So encryption, so hold encryption aside for the moment, let's look at a JPEG, a JPEG or MPEG. So what does it do? It takes a signal that otherwise has a lot of information in it, but maybe not so much, and it somehow combines content in a way that reduces...

• 14:28Neil deGrasse Tyson?

  The total information a little bit, but retains as much as it can so that you can minimize the size of the signal as you transport it. Okay? So, in an image of you right now, there's a large white area background. I can represent that mathematically, rather than having to retain all the details of that. And my mathematical representation is more efficient to move through space, through anywhere, than if I represented the whole thing. So, so there is a hypothesis that a sufficiently intelligent alien will take their signal and JPEG it so effectively and so efficiently, if I can use that JPEG as a verb, that there'll

• 15:10Neil deGrasse Tyson?

  be no discernible information left for someone to reach in and decode it. And so they're perfectly communicating with one another all the time, but we, trying to eavesdrop, will think it's completely noise.

• 15:23Charles Liu?

  Now, so this is an accidental kind of encoding?

• 15:27Neil deGrasse Tyson?

  Yeah, an accidental. So if you want to eavesdrop on civilizations, the most efficient way to send signals is to take whatever is decodable in the signal and re-represent it more efficiently.

• 15:37Charles Liu?

  Right. Well, that kind of data compression that you described for JPEGs and so forth, they have an algorithm, right? So, you can, if you knew how they compressed it, you could unravel this information.

• 15:50Neil deGrasse Tyson?

  Well, that's the key, but then you have to send the key on the other side. So we'd have to ask the aliens, "Please give us a key to your encoding method so that we can eavesdrop."

• 15:58Eugene Mirman?

  Okay, so no one thinks that we're encrypting some stuff, they're encrypting stuff so strongly? Not encrypting, but, but, um...

• 16:05Charles Liu?

  Compressor, compressing.

• 16:07Neil deGrasse Tyson?

  Yeah, it's not so much encryption. It's compressing a signal so efficiently

• 16:11Eugene Mirman?

  Yeah.

• 16:12Neil deGrasse Tyson?

  that the eavesdropper on it will no longer be able to distinguish it just from noise. Because if there's any discernible signal left in it, left in it, that meant there's more encryption, there's more

• 16:24Eugene Mirman?

  Compression.

• 16:25Neil deGrasse Tyson?

  Compression, that it can still survive.

• 16:27Eugene Mirman?

  Then the other question is, are there other ways to sense life remotely? But I don't know that they're mutually exclusive.

• 16:32Neil deGrasse Tyson?

  Well, just see if they're polluting their atmosphere on the planet.

• 16:36Eugene Mirman?

  Just look for planets with other cars?

• 16:38Neil deGrasse Tyson?

  Yeah, if the exo-planet has aerosols, ozone depletion, smog, that's a guarantee there's

• 16:46Eugene Mirman?

  Lamborghars.

• 16:47Neil deGrasse Tyson?

  No sign of intelligent life.

• 16:48Charles Liu?

  And if, if we are able to watch some system for a long period of time, for example, we can watch for periodic behavior. Right, like just the way that decades ago, people thought that maybe pulsars, which are dead stars that turn very rapidly, maybe that their regular beating was a sign of intelligent life.

• 17:09Neil deGrasse Tyson?

  Right, right.

• 17:10Charles Liu?

  If we had many such beats coming from, say, a single solar system or something like that, then we might imagine that there were many such things happening and if there were not-

• 17:18Neil deGrasse Tyson?

  In other words, it's not random and so you've got a-

• 17:20Charles Liu?

  Yes, finding non-random-

• 17:21Neil deGrasse Tyson?

  Yeah, if it's not random and it's predictable, then maybe somebody's doing the non-randoming and the predicting on the other end.

• 17:28Charles Liu?

  Right.

• 17:28Neil deGrasse Tyson?

  Yeah, we got just a few more seconds for this segment. Do you have a quick one or do we have to delay it to-

• 17:33Eugene Mirman?

  I'll ask a quick one.

• 17:34Neil deGrasse Tyson?

  Quick one, go.

• 17:35Eugene Mirman?

  Uh, Linton John Davidson from Facebook asks, "How do I get people interested in science?"

• 17:41Neil deGrasse Tyson?

  That's a quick one. You're lying, you are lying, you are li-

• 17:46Eugene Mirman?

  You said quick and what I interpreted as, I could read that very quickly.

• 17:50Neil deGrasse Tyson?

  Charles, give me your best eight-second answer to that.

• 17:53Charles Liu?

  Listen to Neil.

• 17:58Neil deGrasse Tyson?

  You're listening to StarTalk. Stay tuned for another segment. Welcome back to StarTalk. Here's more of this week's episode.

• 18:21Eugene Mirman?

  Matt Alley from Facebook slash San Antonio asks, "Trillions of years in the future when the universe is in its final whimpers, how might an advanced civilization be able to hold on to survival by harvesting energy from the last remaining celestial bodies?"

• 18:37Neil deGrasse Tyson?

  Ooh.

• 18:38Charles Liu?

  Wow, well, yes.

• 18:40Neil deGrasse Tyson?

  They're talking about a future where all the gas that currently coexists with stars has been turned into stars. And the stars, one by one, start to burn out.

• 18:53Eugene Mirman?

  Mm-hmm.

• 18:53Neil deGrasse Tyson?

  And so, when you go some trillions of years into the future, they will be the last civilization on the last planetary system around that last star. So Charles, what are your reflections on that?

• 19:05Charles Liu?

  Well, uh, he, the questioner may be referring even further into the future, when protons themselves start to break down, and then black holes themselves dissipate through Hawking radiation, uh, ten to the one hundred years from now. Uh, in that case, then there's really no way to harness that energy, because it's all kind of waste heat, entropy, and so forth. But you could imagine-

• 19:29Neil deGrasse Tyson?

  Wait, just to be clear, so what we're saying is, you can have stars burn down, but there's still other ways to extract energy from phenomenon in the universe. And, and, but the universe is actually winding down in every possible measurable way.

• 19:46Charles Liu?

  Right.

• 19:46Neil deGrasse Tyson?

  And so, when the particles decay to even lighter, smaller particles, then they can't decay into something else. And then you are left with a particle-energy wasteland.

• 19:57Eugene Mirman?

  But is it, is it possible to have some sort of artificial planet that you live on that-

• 20:02Neil deGrasse Tyson?

  No, no, that's, this is the, this is the deep part about it. Because anything artificial meant you created a thing that has a metabolism and a source of energy to drive it.

• 20:11Eugene Mirman?

  And the energy will be completely gone.

• 20:13Neil deGrasse Tyson?

  The very fact that you would claim to be alive in that situation. You, you are producing energy. You have a body temperature above air temperature. You, you, you are a machine.

• 20:23Eugene Mirman?

  Thank you.

• 20:24Neil deGrasse Tyson?

  You can-

• 20:27Neil deGrasse Tyson?

  And even when you die, you're, there's a, you're a microbial machine, with your molecules are still decaying.

• 20:34Eugene Mirman?

  There won't be enough dead bodies for this artificial planet to keep eating, is what you're saying.

• 20:39Neil deGrasse Tyson?

  Charles, yeah, how about the dead body energy source?

• 20:42Charles Liu?

  Well, you could do the best you can, but in the end, once you get to the true heat death of the universe, uh, there's really nothing you can do, other than, I don't know, maybe start a new universe.

• 20:51Eugene Mirman?

  Ah-ha! There is a solution, and it's to start a new universe.

• 20:56Charles Liu?

  I didn't invent that solution. You, you should, uh, refer to one of Isaac Asimov's great short stories, called "The Last Question."

• 21:04Neil deGrasse Tyson?

  Oh.

• 21:05Charles Liu?

  I think it's really, really profound and deep. He wrote it very, very well.

• 21:08Neil deGrasse Tyson?

  Okay, alright. I, I think I've read that long ago, but I'm gonna pick it up again. You'll find out.

• 21:13Eugene Mirman?

  Right.

• 21:13Neil deGrasse Tyson?

  Thanks for that reminder.

• 21:14Eugene Mirman?

  Start a new universe.

• 21:15Neil deGrasse Tyson?

  Create a new universe.

• 21:16Eugene Mirman?

  I don't know, if it's trillions of years from now, that science might exist.

• 21:19Neil deGrasse Tyson?

  All right.

• 21:20Eugene Mirman?

  All right.

• 21:20Neil deGrasse Tyson?

  What else you got?

• 21:21Eugene Mirman?

  Uh, I have more. Okay, Jazz, uh, that's, uh, Jazz Gonzalez asks, um, hypothetically, if someone was to successfully create and open a wormhole to go back to a past time, would that wormhole continue to suck in atoms in the environment around it, eventually imploding and possibly destroying the universe around us?

• 21:42Neil deGrasse Tyson?

  Yes.

• 21:49Charles Liu?

  No.

• 21:52Neil deGrasse Tyson?

  Okay.

• 21:53Eugene Mirman?

  Right.

• 21:54Charles Liu?

  No.

• 21:55Neil deGrasse Tyson?

  Wait, wait, wait, so, wait, so.

• 21:57Eugene Mirman?

  Are there a handful of reasons or just like, no?

• 22:00Charles Liu?

  Well, a wormhole, when you create something like that, um, it's naturally going to collapse in on itself.

• 22:09Neil deGrasse Tyson?

  So it's unstable?

• 22:10Charles Liu?

  Yeah, unless you continue to put tremendous amounts of energy to keeping it open, right? Uh, and so it won't spontaneously sort of go out of control and grab as much stuff as possible, sort of sucking everything in.

• 22:24Neil deGrasse Tyson?

  What would be cool, though, is if the wormhole, which gives, does give you access to the past, which does give you access to the past through certain trajectories through it.

• 22:33Charles Liu?

  Yes.

• 22:34Neil deGrasse Tyson?

  If you put the entire universe back through the wormhole, you can send the whole universe back, uh, to yesterday.

• 22:42Charles Liu?

  Yeah. Whoa. How about that?

• 22:45Neil deGrasse Tyson?

  In principle.

• 22:46Eugene Mirman?

  Hmm, great. Did we just, what did we just discover? What exactly are you thinking?

• 22:51Neil deGrasse Tyson?

  Call me later on that one. We, we'll figure, we got the equations on that.

• 22:55Charles Liu?

  I think we got a paper to write.

• 22:56Neil deGrasse Tyson?

  Yeah, yeah, okay. All right, what else you have?

• 22:58Eugene Mirman?

  Okay.

• 22:59Neil deGrasse Tyson?

  Well, we just, just before we went to the break, there was that question, please explain how big a what is? A gram? What was?

• 23:04Eugene Mirman?

  Uh, the, no, the gram, uh, sorry, it was, it was around here. Oh, yeah.

• 23:10Charles Liu?

  Gram's number.

• 23:10Eugene Mirman?

  Explain gram's number, like Graham cracker.

• 23:13Charles Liu?

  G R A H A M.

• 23:15Eugene Mirman?

  Yeah.

• 23:16Charles Liu?

  Apostrophe S.

• 23:17Eugene Mirman?

  I had assumed it was like, uh, like.

• 23:19Neil deGrasse Tyson?

  Sorry, I'd never heard of it.

• 23:20Eugene Mirman?

  Some theorem.

• 23:20Neil deGrasse Tyson?

  I've never heard of it. Have you?

• 23:21Charles Liu?

  It's, it's, if you take a certain, uh, geometric expansion of numbers to try to get to big numbers, you know how like, uh, a billion is? A big number because it's got nine zeros after a one and a googles even bigger because it's got one hundred zeros.

• 23:35Eugene Mirman?

  Yeah, I read about that in Numbers magazine.

• 23:37Charles Liu?

  A googolplex, which is one.

• 23:39Neil deGrasse Tyson?

  Also, it's one of those big numbers that has a name is what you're saying.

• 23:42Charles Liu?

  It's a gigantic number and it's based on you can construct it using a geometric expansion.

• 23:47Neil deGrasse Tyson?

  The only big number I knew of was Skew's number and I didn't know Graham Graham had a number too.

• 23:51Eugene Mirman?

  A big Skew's number, which is bigger, you think?

• 23:52Neil deGrasse Tyson?

  That's ten to the tenth to the tenth to the thirty-fourth power.

• 23:55Eugene Mirman?

  Why is why so weird at the end?

• 23:57Neil deGrasse Tyson?

  Which dwarfs a googolplex. It's self-dwarfing.

• 24:00Eugene Mirman?

  Why is it to the thirty-fourth, not thirty-fifth?

• 24:02Neil deGrasse Tyson?

  Cause, cause, cause Skew's did it.

• 24:06Eugene Mirman?

  Okay.

• 24:07Neil deGrasse Tyson?

  No, no, I don't know. They come up with these numbers, that's what I'm saying. And it has surely has some significance in mathematics.

• 24:12Eugene Mirman?

  Right.

• 24:12Neil deGrasse Tyson?

  That I cannot glean.

• 24:13Eugene Mirman?

  Okay.

• 24:14Neil deGrasse Tyson?

  At this point.

• 24:14Charles Liu?

  Right. Now Graham's number is actually way larger than even Skew's number. I don't know exactly how.

• 24:20Eugene Mirman?

  Three times as large?

• 24:21Neil deGrasse Tyson?

  It's twice as big.

• 24:23Eugene Mirman?

  It's big. It's very big.

• 24:25Charles Liu?

  If, what I have heard is that if you take, um, all the numbers that Graham's number would take to write it out in, in actual physical form, even if each number.

• 24:38Neil deGrasse Tyson?

  Me, numeral, each, each numeral.

• 24:39Charles Liu?

  Were smaller than an atomic nucleus, there would still not be enough room in the entire observable universe to hold the representation of Graham's number.

• 24:49Eugene Mirman?

  It's a very big number.

• 24:51Neil deGrasse Tyson?

  Thank you, Eugene, for confirming that fact. After Charles just explained how big it was.

• 24:57Eugene Mirman?

  Now I really have a sense, it sounds quite big.

• 25:00Neil deGrasse Tyson?

  Okay. I will say that.

• 25:02Eugene Mirman?

  All right, uh, let's, let's go, all right. Uh, from Eddie from Godly Texas asks, uh, regarding the Fermi paradox, if aliens do exist, which of the possibilities do you think is the most likely scenario?

• 25:17Neil deGrasse Tyson?

  All right, Charles and I will trade off on this. I would say the most likely scenario, I have two most likely scenarios. One of them is that they have actually visited Earth.

• 25:25Charles Liu?

  Well, do we need to explain to people what Fermi paradox is to begin with?

• 25:28Eugene Mirman?

  That's probably a great call.

• 25:30Neil deGrasse Tyson?

  I thought Eugene would do that, though, but.

• 25:32Eugene Mirman?

  Sure. I'm assuming it's, uh, the ways aliens might have existed or visited.

• 25:36Neil deGrasse Tyson?

  No, no, so if you can run the numbers on this and. If aliens are like humans and live as long as humans do and are ambitious like humans, then they might have a space program and then they would go colonize a planet.

• 25:48Eugene Mirman?

  Yep.

• 25:49Neil deGrasse Tyson?

  And then that colony would then build its own space program and colonize two planets. And then those-

• 25:54Eugene Mirman?

  I would have colonized two planets.

• 25:55Neil deGrasse Tyson?

  Oh, no. So, so we-

• 25:56Eugene Mirman?

  That's-

• 25:56Neil deGrasse Tyson?

  We're one planet, we colonize two planets. Each of those two planets colonize two planets, alright? So you, it's, it's two to the nth power. It grows rapidly. It's, it's an exponential. And it turns out, you can occupy every single planet in the galaxy in less time than it takes for you to evolve from one species to another. And so, in the, under that calculation, if there are intelligent aliens anywhere who had this ability, where are they now? They should be pitching tent right next to us.

• 26:29Eugene Mirman?

  Mm-hmm.

• 26:30Neil deGrasse Tyson?

  And, and Mico Fermi, a famous Italian physicist, uh, proposed this question. So either, there are no aliens out there, or there's some other explanation for why we don't see them. And so I have two explanations. One of them is, th- they came to Earth already-

• 26:47Eugene Mirman?

  Mm-hmm.

• 26:47Neil deGrasse Tyson?

  And, and saw humans and concluded there's no sign of intelligent life on Earth and left. Okay, had, did have one. Then another one is maybe they landed the same day that Comic-Con was happening. And so, nobody-

• 27:02Eugene Mirman?

  They're in San Diego.

• 27:03Neil deGrasse Tyson?

  They're in San Diego. Uh, but Charles, you have a, do you have a, a less comical answer to this question? It's a very serious question.

• 27:11Charles Liu?

  Well, um, one of our colleagues, uh, Steve Soder, actually told me this idea.

• 27:18Neil deGrasse Tyson?

  Oh, Steve Soder co-wrote both Cosmos series in 1980 and the one that I, that I, uh, hosted. Go on.

• 27:24Charles Liu?

  Yeah. Um, Steve said that it's possible that once intelligent civilizations achieve the ability to colonize, they wind up all destroying themselves before they successfully do the colonization. Uh, if you can, for example, create a spacecraft that can go some tremendous speed, a one percent the speed of light or something like that, you're too tempted to use it as a weapon against your enemies rather than doing something productive like exploring space.

• 27:53Neil deGrasse Tyson?

  So I think that, I think the argument was even more subtle than that. It was, whatever is the gene for expansionism-

• 28:01Neil deGrasse Tyson?

  If I expand to here and you expand to there, I also want to expand to where you went.

• 28:08Charles Liu?

  Right.

• 28:08Neil deGrasse Tyson?

  And so you have overlapping borders of expansion and that is, has the seeds of its own undoing.

• 28:16Charles Liu?

  Right, so it creates annihilation before we see them. So we, in that scenario, are doomed to, to self-destruction at some point when we get sufficiently advanced enough, uh, technology to do so.

• 28:28Eugene Mirman?

  It's a very unidelic Star Trek is what you're describing.

• 28:31Neil deGrasse Tyson?

  Yeah, yeah.

• 28:32Charles Liu?

  And, and I think Eugene's hit the other one that I think of, right? Is that, uh, aliens are sufficiently benevolent that they hide and disguise whether or not they're there. So that they allow us to develop and become citizens of the universe in a cheerful.

• 28:47Neil deGrasse Tyson?

  That is so beautiful, Charles.

• 28:48Charles Liu?

  I didn't invent it.

• 28:49Neil deGrasse Tyson?

  Or we are their computer program and, and somebody's PhD thesis to create a universe.

• 28:55Eugene Mirman?

  I mean.

• 28:56Charles Liu?

  Yeah.

• 28:57Eugene Mirman?

  How long would it take us? Like, how long do you think before humans could call, like actively colonize some other place?

• 29:02Neil deGrasse Tyson?

  You have to colonize it on a level where then you become another civilization that needs no reference back to the original. So, we speak English.

• 29:10Eugene Mirman?

  Yeah.

• 29:10Neil deGrasse Tyson?

  In the United States because colonists came from England.

• 29:13Eugene Mirman?

  Yeah.

• 29:14Neil deGrasse Tyson?

  And, and so, England in a sense landed on the moon because descendants of their colonies did that.

• 29:20Eugene Mirman?

  Right.

• 29:21Neil deGrasse Tyson?

  Right? So, you, you, you have to become a self-sufficient thing and not just still on the dole.

• 29:26Eugene Mirman?

  Meaning how, how likely is it that there's civilizations like ours that just also can't colonize? That's the.

• 29:32Neil deGrasse Tyson?

  Because we're too stupid or too ineffective to know how.

• 29:36Eugene Mirman?

  But, uh, and then there's other ones like that too.

• 29:40Neil deGrasse Tyson?

  Yeah, I don't, I don't see any signs on our horizon that we are that kind of civilization. That we're gonna occupy every corner of the galaxy because we're that awesome. I don't see that happening.

• 29:48Eugene Mirman?

  Alright.

• 29:49Neil deGrasse Tyson?

  Next question, what do you have?

• 29:51Eugene Mirman?

  Okay. Ronald James from, uh, on Facebook asks, "How fast is the universe expanding from an Earth-centric perspective in light years per Earth year? Also, how fast is the rate of expansion, same units increasing due to this dark energy junk?"

• 30:08Neil deGrasse Tyson?

  Yeah, Charles, you have those numbers on in your head?

• 30:10Charles Liu?

  Well, the current expansion rate of the universe, astronomers refer to as the Hubble constant, right? Which is seventy-three kilometers per second per megaparsec.

• 30:21Neil deGrasse Tyson?

  Hmm.

• 30:22Charles Liu?

  Uh, and if you do the proper unit calculations, that just basically means that we are expanding at about one-fourteen billionth of our own diameter per second.

• 30:37Neil deGrasse Tyson?

  Oh, okay, so every year we expand one-fourteen billionth.

• 30:41Charles Liu?

  One-fourteen billionth of our current diameter.

• 30:44Neil deGrasse Tyson?

  Gotcha.

• 30:45Eugene Mirman?

  Okay. You have that. I did the calculation.

• 30:48Neil deGrasse Tyson?

  You agree, yeah, you agree.

• 30:49Eugene Mirman?

  Yeah, yeah. When you weren't sure, I was like, I, okay.

• 30:52Neil deGrasse Tyson?

  By the way, you can imagine growing anything at that rate.

• 30:54Eugene Mirman?

  Yeah.

• 30:55Neil deGrasse Tyson?

  Right? What grows at one-fourteenth of its size? No, one-fourteen billionth of its size per year?

• 31:02Eugene Mirman?

  Hatred.

• 31:03Neil deGrasse Tyson?

  So that is so that that's the rate at which the universe is growing.

• 31:08Eugene Mirman?

  Okay.

• 31:09Neil deGrasse Tyson?

  So, good way to think about it, Charles. I'll use that again for sure.

• 31:11Eugene Mirman?

  Okay. Ocean, uh, McIntyre asks, could neutrinos and their oscillations play a role in detecting mapping and understanding dark energy?

• 31:25Charles Liu?

  Ooh. Hundred percent. Yeah. Um, Neil, you want to explain neutrino oscillations to people?

• 31:31Neil deGrasse Tyson?

  Yeah, so neutrino, they're different species. It's like.

• 31:35Eugene Mirman?

  Call. I like the answer of yes. And then I'm like, no, yeah, but I wonder, other than on Star Trek where you create a net and then you can see the invisible alien, but how else does it work?

• 31:46Neil deGrasse Tyson?

  So neutrinos is one of the, are one of the fundamental particles of the universe. Uh, neutrinos don't decay into some other kind of particle, so that's, we consider them fundamental. And there.

• 31:57Eugene Mirman?

  Would you have enough to use the, to as energy at the end of the universe?

• 32:00Neil deGrasse Tyson?

  No, because once you decay to the lowest energy neutrino, you're done. So we have, there are three different families of neutrinos, and the neutrino oscillations is a fancy word for saying, a neutrino moving through space can actually transmogrify into another species of neutrino. So it'd be like I toss you a basketball and you. Caught a football.

• 32:19Eugene Mirman?

  Right.

• 32:20Neil deGrasse Tyson?

  Right. And that story has an interesting past, uh, history because we made a prediction of what rate the sun should be producing neutrinos based on our understanding of how the sun works. And we were not measuring those neutrinos. So either we were completely wrong with our understanding of thermonuclear fusion, or the neutrinos was, were misbehaving. And that's what we found. We didn't know the neutrino would turn into a different species between being formed in the center of the sun and reaching us here on earth and our detector.

• 32:49Eugene Mirman?

  And there's no transfer of energy between it changing from a basketball to a football?

• 32:53Neil deGrasse Tyson?

  Uh, generally you lose energy. What happens there? You, you?

• 32:56Charles Liu?

  Yeah, you do change energy.

• 32:57Neil deGrasse Tyson?

  Yeah, yeah. It's an energy state.

• 32:58Charles Liu?

  The missing neutrino problem was precisely that because I realized that the detectors that we were trying to use to find the neutrinos from the sun were only sensitive to one kind of neutrino at a certain energy level and not to the other kind.

• 33:10Neil deGrasse Tyson?

  Right, right. Exactly.

• 33:14Neil deGrasse Tyson?

  You're listening to StarTalk Radio. Stay tuned. More up next.

• 33:31Neil deGrasse Tyson?

  Welcome back. Here's more of StarTalk.

• 33:37Eugene Mirman?

  James Kultus from Twitter asks, what are some of the most exciting astrophysics discoveries we've made in 2015?

• 33:43Charles Liu?

  Oh, well, the new horizons flyby of Pluto.

• 33:46Neil deGrasse Tyson?

  Pluto. Pluto was rocking the whole year.

• 33:48Charles Liu?

  Dawn's flyby of Ceres. And on September 14th, 2015, there was a gravitational wave that came through earth.

• 33:57Neil deGrasse Tyson?

  So yeah, so that happened in September. So that was good. Keep going on the list.

• 34:00Eugene Mirman?

  Oh.

• 34:00Charles Liu?

  More?

• 34:01Neil deGrasse Tyson?

  No, yeah, yeah. You gave three things. Go on. Anything else?

• 34:04Charles Liu?

  Duh. Gee.

• 34:05Neil deGrasse Tyson?

  I got one. Uh, I got one. I, I think this counts. SpaceX successfully relanded the first stage of its rocket. Which opens up a reusability of rockets for the future. It's a, it's a commercial technological achievement, but I think we shouldn't, uh, we shouldn't underestimate what potential value that can have in inexpensive spaceflight going forward.

• 34:28Charles Liu?

  Yeah, Blue Horizons did something like that too, right?

• 34:30Neil deGrasse Tyson?

  Yeah.

• 34:31Charles Liu?

  Or, excuse me.

• 34:32Neil deGrasse Tyson?

  No, but it didn't go into orbit.

• 34:33Charles Liu?

  That's right.

• 34:34Neil deGrasse Tyson?

  Yeah. This one orbited, deployed satellites, came back and landed safe.

• 34:37Charles Liu?

  The, the first stage came down.

• 34:40Neil deGrasse Tyson?

  First stage, and the rest of it went up to orbit, that's correct. But in this other one, I don't think anything went into orbit.

• 34:44Charles Liu?

  Right, it just went up to the hundred kilometer level.

• 34:47Neil deGrasse Tyson?

  Yeah, the, the atmosphere edge, yeah, yeah. So, good question there, okay, keep it coming.

• 34:52Eugene Mirman?

  Uh, B Damari asks, uh, can dark matter be 3D matter in another dimension? Maybe it fell into a black hole?

• 35:01Charles Liu?

  Uh, it could have, but the thing is, we know so little about dark matter, it can literally be anything.

• 35:07Eugene Mirman?

  That's why we call it dark matter.

• 35:08Charles Liu?

  Cosmologist Rocky Cobb likes to say that dark matter is a model in search of a theory, which basically means, almost like, uh, millennia ago, when people designed things like epicycles and, and retrograde motion explanations, uh, that we're almost at that stage. So, it could literally be anything, it's not likely to be certain things, but it could be anything.

• 35:29Eugene Mirman?

  Okay.

• 35:30Neil deGrasse Tyson?

  I gotta go with Charles on that.

• 35:31Eugene Mirman?

  Yeah, me too. We're, all three of us. Uh, Jacob Saber asks, uh, when the sun becomes a red giant, what will happen to the asteroid belt and surviving planets?

• 35:43Neil deGrasse Tyson?

  Ooh, nothing.

• 35:46Eugene Mirman?

  Though.

• 35:47Neil deGrasse Tyson?

  Nothing. Yeah, so the red, the sun becomes a red giant, and it'll make a very beautiful nebulae surrounding a very dense core, but, uh, that, the red giant is not going to reach the size of the asteroid belt in the red giant stage, it's not. And so, the, the asteroid belt doesn't know, or care, that the sun...

• 36:07Neil deGrasse Tyson?

  Swelled up, it's the same amount of mass centered at the center of the solar system. So, uh, now the, the heat distribution among the planet, the, the family of planets and comets and asteroids will be different. Earth would have been burnt to a cinder. Mercury would have been vaporized deep within. Uh, same with Venus. So, yeah.

• 36:26Eugene Mirman?

  Is there a planet we could move to that would be maybe equivalent of what Earth is?

• 36:30Neil deGrasse Tyson?

  Uh, Charles, I think we can move to Mars, can't we?

• 36:32Charles Liu?

  Uh, no, I'm afraid not.

• 36:34Neil deGrasse Tyson?

  Is it too close?

• 36:35Charles Liu?

  Mars is still too close.

• 36:36Neil deGrasse Tyson?

  Uh, one of the moons of Jupiter then.

• 36:38Charles Liu?

  You might do alright in the moons of Jupiter, but there is still a big solar wind, right? Remember that the process of becoming a red giant takes hundreds of millions of years. And so in that process, as it grows, more solar material will slough off. And if there's too much of that, it will still blow away atmosphere and things like that. But, uh, once we get out to Titan or maybe Triton, the solid material should be able to hold together at least for a time.

• 37:02Neil deGrasse Tyson?

  Right, and we mentioned the moons of Jupiter because Jupiter itself offers no surface on which to land.

• 37:07Charles Liu?

  Right.

• 37:08Neil deGrasse Tyson?

  But, of course, the moons do.

• 37:09Eugene Mirman?

  Maybe we go to those moons and then as we do that and then we move to the next place. I mean, it's not ideal.

• 37:14Charles Liu?

  But you know, that's five billion years from now.

• 37:17Eugene Mirman?

  Yeah.

• 37:18Charles Liu?

  Five billion years of evolution, if we're still needing to be in spaceships to go somewhere solid to live and survive, I think we're in deep trouble evolutionarily.

• 37:25Neil deGrasse Tyson?

  Yeah.

• 37:26Eugene Mirman?

  Meaning you think we'll be energy beings?

• 37:27Neil deGrasse Tyson?

  That's kinda what he said.

• 37:29Eugene Mirman?

  Fly, fly around solving crimes?

• 37:31Neil deGrasse Tyson?

  That's kinda what he said, we'll be...

• 37:33Charles Liu?

  I'd appreciate that, sure.

• 37:34Neil deGrasse Tyson?

  Okay.

• 37:35Eugene Mirman?

  Yeah.

• 37:36Neil deGrasse Tyson?

  Alright.

• 37:37Eugene Mirman?

  Anybody you think it'll take time, like I can't do it in the next year or two?

• 37:39Charles Liu?

  Let's just say it's something to look forward to. I wouldn't change my retirement plans.

• 37:42Neil deGrasse Tyson?

  Next question.

• 37:43Eugene Mirman?

  Okay. Um, Terry Carter asks, uh, is there presently any living thing on Earth that could live on the moon or Mars?

• 37:52Neil deGrasse Tyson?

  Yeah, not on the surface, I don't think on the surface, but you can probably hide stuff in the subterranean caverns of Mars. What do you think, Charles?

• 38:01Charles Liu?

  Yeah, it, I think, uh, you know, tardigrades have been big in the news lately as far as extremo tolerant organisms are concerned. These are little mites that live... For example, in places like your eyelashes, right? Uh, they can survive the vacuum of space for a period of time, certainly in, if we go into low earth orbit and then bring them back down, they have been shown to be able to survive the rigors of space for a while. If you can dig them down into, say, Mars, where there's quite a bit of frozen water and maybe occasionally that frozen water becomes liquid, those tardigrades could survive. They probably wouldn't like it, but they could survive.

• 38:37Neil deGrasse Tyson?

  But probably not the moon, we're saying.

• 38:39Charles Liu?

  Yeah, uh, we don't know enough about the subsurface environment of the moon to really know whether they could survive there. I imagine maybe there are some microorganisms that could, but.

• 38:50Neil deGrasse Tyson?

  But let me, let me broaden that and say, everything we know about complex organisms tells us we're hosed.

• 38:56Eugene Mirman?

  The cats would not. No, no chance.

• 38:59Charles Liu?

  Right, not, no.

• 39:01Neil deGrasse Tyson?

  No cats. We're under the five-minute warning.

• 39:03Eugene Mirman?

  Okay.

• 39:03Neil deGrasse Tyson?

  And with this, we're now the lightning round, okay? Charles, it's, uh, uh, we're, it's soundbite answers. We're gonna get it made through. Okay, ready, go.

• 39:11Eugene Mirman?

  Okay, Thomas asks, if a W-hole entrance exists within an object sphere of influence, does it affect objects on the other side?

• 39:20Neil deGrasse Tyson?

  I don't know. Charles, go.

• 39:22Charles Liu?

  Yes, but we don't know how yet.

• 39:24Neil deGrasse Tyson?

  Okay.

• 39:24Eugene Mirman?

  Okay.

• 39:25Neil deGrasse Tyson?

  Next.

• 39:26Eugene Mirman?

  The Teen Poet asks, is it possible to use gravity to manipulate the flow and speed of light and therefore outspeed it?

• 39:34Charles Liu?

  No.

• 39:35Eugene Mirman?

  Okay.

• 39:35Neil deGrasse Tyson?

  I agree with that. You can't beat a light beam anywhere unless you.

• 39:40Eugene Mirman?

  Not even if you're riding, you're a light beam riding a gravity wave?

• 39:43Neil deGrasse Tyson?

  No, no, you could, you know, if you ride, uh, you can't surf a gravity wave to go faster than the gravity waves.

• 39:48Charles Liu?

  No. The universe can expand faster than the speed of light overall, but anything in the universe in spacetime cannot go faster than a beam of light going through that same spacetime area.

• 39:57Neil deGrasse Tyson?

  Yeah, the light wins every, every time. Okay, next.

• 40:00Eugene Mirman?

  Okay, Jeffrey wants to know, do you think we could put small asteroids in an orbit around the sun to use as a midpoint to get to Mars?

• 40:08Charles Liu?

  In about sixty or seventy years, I think. What do you think, Neil?

• 40:11Neil deGrasse Tyson?

  I don't see the need to have, have a midpoint. What you would want are filling stations along the way and doing a midair or mid-space refueling because you can have energy of motion to get you from Earth to Mar- to Mercury. And that energy, you don't want to compromise that energy. You want to stay with it all the way and ride it in.

• 40:28Eugene Mirman?

  You want to have moving gas stations.

• 40:30Neil deGrasse Tyson?

  Moving gas stations, exactly. Filling stations. Uh, next.

• 40:33Eugene Mirman?

  Okay, uh, if you had the equivalent money that we spent for Apollo today, what would your goal be?

• 40:40Neil deGrasse Tyson?

  Ooh, uh, that would, in today's dollars, it's about a hundred billion dollars.

• 40:44Eugene Mirman?

  Mm-hmm.

• 40:45Neil deGrasse Tyson?

  And, I don't, Charles, what would you do with a hundred billion dollars?

• 40:48Charles Liu?

  I would try to stabilize the carbon dioxide emissions in our atmosphere.

• 40:55Neil deGrasse Tyson?

  Charles, that's so responsible of you. I mean, come on.

• 40:59Eugene Mirman?

  And then, once that was done, would you go to Mars?

• 41:02Charles Liu?

  Oh, a hundred billion isn't enough to go to Mars with modern technology.

• 41:05Neil deGrasse Tyson?

  I know what I'd do. Okay, let me, I would try to be more noble than Charles was. I would use the hundred billion dollars to make all seven billion people on Earth so scientifically literate that any next decision they make

• 41:18Eugene Mirman?

  Alright.

• 41:19Neil deGrasse Tyson?

  will involve going to Mars. Because they'll know the wisdom of it.

• 41:23Eugene Mirman?

  And they'll

• 41:24Neil deGrasse Tyson?

  And they'll fix, and they'll solve the problem. Next.

• 41:26Eugene Mirman?

  Okay, what are some tips you would give to someone studying physics in college?

• 41:32Neil deGrasse Tyson?

  Uh, take the hardest classes you can. Don't worry about whether it's an A or B in your grade, because at the end of the day, people will beat a path to your door for accomplishing things that no one else could, because that's what it means to take a hard class. Take an easy class and get an A, you show people your grade, but that's the grade everyone else got. And you're no longer distinguished in the marketplace.

• 41:51Charles Liu?

  Neil, that is the most eloquent explanation that I've ever heard of that correct phenomenon.

• 41:56Neil deGrasse Tyson?

  Okay, says the man who knew nothing but straight A's his whole life. But go, go.

• 42:02Eugene Mirman?

  Why, why do all the planets orbit the sun in the same direction?

• 42:06Neil deGrasse Tyson?

  Oh, so, uh, back in the mid seventeen hundreds, this is a, this, we think, that was solved by some great philosophers back then. One of them, was it Laplace? Uh, yeah, yeah, it's Laplace. So, it's called the nebular hypothesis. You have a huge cloud out of which you will make the solid stuff from collapsed pockets within it. It rotates. Everything in the universe rotates. And as this cloud collapses, it speeds up. pockets form and therefore everything that forms from that cloud will rotate with the same sense of direction as everything else and so so so potent is that understanding that when something is moving in a weird direction relative to it that tells us it has a different origin and it's interloping through our own solar system and it's really

• 42:50Neil deGrasse Tyson?

  really cool I think that Charles do I get your amen on that?

• 42:53Charles Liu?

  You're right unless maybe something in the solar system whacked something else in that solar system.

• 42:57Neil deGrasse Tyson?

  Yeah you can get whacked in the solar system.

• 42:59Eugene Mirman?

  If a moon hits another moon something could go it could go differently.

• 43:02Neil deGrasse Tyson?

  I didn't know you worked for the Sopranos yeah okay.

• 43:04Charles Liu?

  Hey.

• 43:05Neil deGrasse Tyson?

  Yeah you get whacked yeah for example uh uh is it Neptune uh you know Uranus its orbit is flipped completely the other way doesn't rotate in the same rotate in the same direction as everybody else.

• 43:14Charles Liu?

  Oh really?

• 43:15Neil deGrasse Tyson?

  I think something knocked it on its on its ear. You're listening to StarTalk stay tuned for another segment. Welcome back to StarTalk here's more of this week's episode. We're back StarTalk and this is the how tweeted is part of the show Bill Nye joining me here.

• 43:48Bill Nye?

  So good to be here.

• 43:49Neil deGrasse Tyson?

  Good to have you and you tweet at Bill Nye.

• 43:51Bill Nye?

  I do.

• 43:52Neil deGrasse Tyson?

  Very nice so I posted a tweet out not not that long ago just came upon these are like brain droppings each day so but I know you've thought about this so here it is proud to be homo sapiens a curious species with DNA compelling us to explore even if doing so puts your own life at risk.

• 44:09Bill Nye?

  Apparently.

• 44:10Neil deGrasse Tyson?

  Why? If people are ready to kill themselves.

• 44:13Bill Nye?

  Well the word kill themselves are willing to take risks because taking risks well when you take a risk there's a chance you'll succeed at least when I take risks.

• 44:23Neil deGrasse Tyson?

  You know it's interesting because that's not how I think of risk I think when you take a risk there's a chance of you dying.

• 44:27Bill Nye?

  Yeah well there's but there's.

• 44:29Neil deGrasse Tyson?

  That's fascinating.

• 44:30Bill Nye?

  On zero.

• 44:31Neil deGrasse Tyson?

  That's a fascinating other way to think about risk.

• 44:32Bill Nye?

  It is a one sum game that which does not kill you what you presume would leave you alive and the risk is taken to in the with the chance of enriching yourself and let me just put it this way everybody you could you're a woman you're a female.

• 44:49Bill Nye?

  You could go with the accountant there in the cave, in ancient cave days, Og and Oggett back there. Or you could take a chance on, uh, on the guy who's a little wild, who goes over the hill and maybe will invent PayPal and just get crazy rich. And so if you put your cards in with that guy, put your lot in with that guy, there's a chance that you will also succeed.

• 45:14Neil deGrasse Tyson?

  What are you saying about accountants?

• 45:15Bill Nye?

  I'm saying the accountant's a steady guy, but he may not strike it rich. So, uh, there's some value in the striking rich scenario.

• 45:24Neil deGrasse Tyson?

  Okay, but if that were the case, there'd be no accountants?

• 45:27Bill Nye?

  Oh, no, because everybody's got a passage. The guy who goes over the hill may get killed. There's lions and tigers and bears and parasites.

• 45:34Neil deGrasse Tyson?

  That'd be three different continents, actually.

• 45:36Bill Nye?

  Uh, uh, all that aside, I was trying to cover them all. There are penguins, uh, and, uh...

• 45:43Neil deGrasse Tyson?

  You just added a continent, right?

• 45:45Bill Nye?

  And then there's some, there's some new world monkeys that are trouble.

• 45:48Neil deGrasse Tyson?

  No, the point is...

• 45:50Bill Nye?

  Plus, in Australia, everything's venomous.

• 45:53Neil deGrasse Tyson?

  Okay, so, but the guy that goes over the hill gets the, attracts the female, then the male that stays in the cave doesn't reproduce, is that right?

• 46:03Bill Nye?

  No, well, it depends on what choice certain females make. I'm saying there's value in the guy taking risk.

• 46:09Neil deGrasse Tyson?

  Okay.

• 46:10Bill Nye?

  Not that accountants don't take risk, but comedy is based on stereotypes and so, or expectations, which are based on stereotypes. So, my feeling is that the ancient cave accountants were more conservative than the ancient cave over the hill, let's go forward explorers.

• 46:25Neil deGrasse Tyson?

  Okay, and so the over the hill, let's go forward explorers who never came back, the accountant had all the women.

• 46:30Bill Nye?

  Yeah.

• 46:31Neil deGrasse Tyson?

  Okay, that's how, the male accountant had all the women, okay.

• 46:37Neil deGrasse Tyson?

  Thanks for listening to StarTalk Radio. I hope you enjoyed this episode. Many thanks to our comedian, our guests, our experts, and I've been your host, Neil deGrasse Tyson. Until next time, I bid you to keep looking up.