StarTalk Radio - Cosmic Queries: Planet Earth

Episode Date: July 19, 2013

StarTalk Radio comes down to Earth as astrophysicist Neil deGrasse Tyson and comic co-host Chuck Nice answer fan questions about our home planet, from how it formed to how it might end. 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. I'm your host, Neil deGrasse Tyson. I'm an astrophysicist with the American Museum of Natural History right here in New York City. In studio is the one, the only, Chuck Nice. Hey, Neil. What's happening?

Chuck, good to have you. This is the Cosmic Queries edition of StarTalk. Yes, it is. I like to think of it as StarTalk. After hours. But it's not after hours. It's like broad daylight outside right now. So sometimes we do them random, you know, pa-puree, but today it's themed to the Earth.

I haven't seen any of these questions. That is correct. Questions that come in from our fan base and our listeners from all our social networks. That is correct. Why do we make a category? I'm like an astrophysicist. I care about everything that's not Earth. Right. You're not a terrestrial physicist. I'm not a terrestrial physicist. category? I'm like an astrophysicist. I care about everything that's not Earth. Right. You're not a terrestrial physicist.

I'm not a terrestrial physicist. Thank you. He's an astrophysicist. Thank you. So we'll see how far I get. I know some osmotic things that the geophysicists tell me, but otherwise we'll see how. I can answer questions about Earth as a planet. Okay. All right. Well, you know what? We'll find out. We'll see. We'll find out.

That's the first I've ever heard these. Yep. The first time you've ever heard them. That's my favorite part. So let's jump right into it. And we've got Ryan Mizak. Ryan Mizak. Well, the question's from Facebook. Facebook, okay.

But Ryan does not notate where he is from. How was the Earth formed? What happened at the birth of the planet? And that goes for not just this planet, pretty much planets, how we're planets. We can split planets into two varieties, rocky planets, of which we are, and gaseous planets, Jupiter, Saturn, Uranus,

and Neptune are gassy. You mean Uranus is gassy? I had to do it. I had to. Somebody has got to go there. I'm ashamed of myself right now. Somebody in every show's got to go there. Got to go there. Go ahead. All right. So what we think happened here is as the original nebula that formed the solar system, it would form the sun first. That's where the strongest

gravity is, the greatest accelerations of particles into it. You can make the sun. Now that's where the interesting things happen because now the sun begins to heat the remaining rest of the gas that's trying to condense and make other kinds of objects. So in our solar system, we may have had a huge gaseous envelope, but we don't anymore. We don't have enough gravity to hold onto it. Gotcha. All right. You, um, for example, if you have a helium balloon and

you let the gas out, helium travels very fast in our air. So fast that if it gets to the top of the atmosphere, it will escape forever. We don't have enough gravity to hold onto our helium. But Jupiter and Saturn do. So Jupiter and Saturn, they're almost 10% helium in each one of those. So if you don't have enough gravity to begin with, you'll hold your rocks. You don't hold your gas. Gotcha. That's what I'm saying. So now there's a point where Earth would have been sort of molten because things are very hot in the early solar system.

When you're molten, heavy things can fall to the middle and light things rise to the top. So guess what kind of core we have? So we have a very heavy metal core. Metal iron core. Iron core. Yeah, nearly all the iron in Earth is settled to the core. And the light stuff, like what the geologists call the silicates.

So there's a lot of silicon bound with oxygen. Silicon and oxygen, that's like the active ingredient in rock, basically. So these are the light elements compared with iron and nickel and cobalt and all the rest of that. So Earth has been what we call differentiated in its density. And there you have it. And then it cools in place. It cools in place. So then you have different layers and different as you go down.

Now, you know the rarest meteorite? It's called a palisade. That meteorite is the broken remains of a planet that was differentiating its material. The light things floating to the top, the heavy things sinking to the bottom. But it froze before everything fully separated. And you capture the light things rising up through it and the heavy things coming down. It is the combination of these two ingredients in one mass.

So it's those two things kind of passing in the night. Passing in the night. And then there's a snapshot of that found in that rock or that meteorite. Chuck, I could not have said it better. Yes, you could have. No, I could not have said it as simply and beautifully. You came through on that one. Well, I got a simple, beautiful mind.

So there you have the Earth, and we kept our heavier gases in the atmosphere. It's fantastic, man. That was really good. Okay. What else you got? Okay. Let's move on to Omar Buckingham. That's the name.

The third, yes. Where's the Roman numeral? Indeed. Omar Buckingham the third. That's the name. The third, yes. Where's the Roman numeral? Indeed, Omar Buckingham III.

Could a shift in the magnetic poles happen in the near future? How does that occur? And what would that mean for both humans biologically as well as technologically? Okay, dude, the poles are shifting all the time. Okay. All the time. All the time. All right? And we say, oh, the time. Okay. All the time. All the time. All right? And we say, oh, compass points north.

No, it points to the north magnetic pole, which is not near the north geographic pole. Like, Santa is like north pole. Right. Bar none. All right? The magnetic pole is like in Canada somewhere. All right? So people who, in the old days, pre-GPS, who hiked with compasses, would need a magnetic,

what they called it, was it a declination or decrement? They need to know what angle difference between the compass and true north would give you depending on where they were in the world. Is that where true north comes from? True north is Santa. Right. True north is the difference between true north and magnetic north.

That difference you have to keep track of. Gotcha. Otherwise, you're lost, all right? So a compass is only good as how close the north pole is to the north pole, all right? Gotcha. Now, here's something cool. You ready? Do you realize that the north pole of a compass points to the north pole of the earth?

But you've played with magnets before. Mm-hmm. What happens when you bring two North Poles together? Well, they kind of hate each other. They repel. That's right. Yet your North Pole on a magnet is pointing to the North Pole of the Earth. That tells you that Earth's North Pole actually has the South Magnetic Center.

Oh! So it's just the opposite. It's just the opposite. It's just the opposite. It's just the opposite. The North Magnetic Pole of the Earth is Earth's South pole. Oh, man. That's why all North poles of magnets point there.

Oh, my. That is amazing. You didn't know that. No, because you'd think it's North pole. That's what you've been told. That's what you point to if you're North. But you're right. But the North pole of the magnet would not point towards the North pole.

It would go the opposite. It would go the opposite way. So the North pole is actually the north pole. It would go the opposite. It would go the opposite way. So the north pole is actually the south pole. Exactly. I'm just saying. So Saturn is truly at the south pole. Yes, near the south magnetic pole. The south magnetic pole.

The real rotational north pole. That's the real north pole. Exactly. So the poles not only wander, they've actually diminished in intensity and increased over time. Right now we're on a diminishing intensity pole. The worry is if it goes away, then what happens to the solar particles and radiation that hits the earth? Do we all go extinct? We're worried about that. So you look at the record of where the pole has been. We have that because it freezes, quote, freezes into

the lava that comes out of volcanoes. It remembers what orientation the pole was at the time it solidified. So you have a whole tracking of the history of where the magnetic pole was. And after this break, you'll find out whether we go extinct or not. You're listening to StarTalk Radio. Back in a moment. We're back on StarTalk Radio Cosmic Queries Edition. I'm Neil deGrasse Tyson.

Chuck Nice. Yes, Neil. Is with me. Yes, I am. You're one of our regulars, Chuck. I'm Neil deGrasse Tyson. Chuck Nice. Yes, Neil. Is with me. Yes, I am. You're one of our regulars, Chuck. I'm glad to be a regular. I just heard you had a kid. Why didn't you tell me this?

Oh, man, you didn't know? How old's your baby? Well, right now, four weeks. Four weeks? Four weeks. Okay, we call that a month. Just so you know. Well, congratulations, it's your third.

Hey, thank you, it's my third. It's a little girl. Baby-making machine, you. Oh, God, You're telling me. Congratulations. What's her name? Charlie London. Charlie London.

Charlie London is her name. A shout-out to Charlie London. Welcome to the universe. Thanks. Yeah, cool. So, Cosmic Queries edition, we're talking about Earth. And I claim expertise on Earth as a planet, globally, not like Earth as a geologist. Don't ask me what the molecular form of Orthoclase feldspar is.

I won't know. Okay? All right. So I haven't seen these questions before, so what do you have? What's next? Okay, let's move on. And this next question comes from David Worley. This is just a personal question for you.

So this isn't really like a science thing. He's just picking your brain. Even though we are on the air and this is a science show this is true okay okay but you know you gotta sometimes i'll roll with it i'll roll with it taking into account the natural earthbound disasters such as earthquakes flooding drought tsunami and last but certainly not least, volcanoes. Neil, where is the safest place you'd like to live? The safest place. The safest place you'd like to live.

Actually, the safest place is like the International Space Station where you can watch it from above. There you go. No, there are some places that are not as susceptible to natural disaster. The United States, there's all this God bless America stuff, but we lead the world in tornadoes and we get these Mondo hurricanes. We're disaster central. Disaster central. Not only in real life, but in the movies as well. We got everything but the frogs and the locusts. Basically, we have the fires, the floods. We've got all of that. So what you want to be is a place that is not as susceptible to the fluctuations in climate.

And among those places would be like rainforests, for example. Ah. By the way, Seattle is at a latitude that promotes rainforests. So Seattle, I don't know that they have tornadoes floods you know it's pretty stable just this dreary rain the sun never comes out just dreary rain all the time if you're okay with no sun yeah you're cool um and the brazilian rainforest that's why it is so rich in its bio and it's uh it's one of the richest parts of the biosphere. Life can thrive there. Life has a hard time if you stress it with climate, fire, flood, whatever.

Believe me, I know. So the rainforest latitudes are great places. Now, you'd be infected with bugs and other – you get malaria and everything. You'd be dead for other reasons, but not because Earth as a planet killed you. Not to mention all the loggers you'd have to fight off for your rich natural resources. Correct. Yeah.

All right, let's move on to the phone, and I believe on the line... You got a caller. Got a caller. Nice. And this is Magic from L.A., Neal. Magic from L.A. Of course.

Okay. So what is Magic? Magic, are you there? Yeah, I'm here. That's not Magic Johnson. I'm sorry'm here. That's not Magic Johnson. I'm sorry. No, it's not Magic Johnson. No, no.

Okay, Magic, what do you have for us? Well, I wanted to know, if you put all of the natural resources together on Earth, how much would our planet be worth? Oh, he's trying to trade Earth on the open market. What are you, a Ferengi? I'm a registered stockbroker, so I always ask these questions. What is Earth worth?

What is Earth worth? Who would ever think of that? I do know this much. I know we have $60 trillion worth of oil in the ground, which is why we can't get any legislation passed to stop killing the earth right because it's cheaper to pull energy out of the ground right so okay i don't have that number but let me i can address certain aspects

of it there's the oil there's the coal there's the minerals which includes diamond and you know and then there are the the the elements from the periodic table that have value to our industry there's copper there's cobalt there's iridium there's um so you just go right on down there's uranium helium is becoming expensive okay yeah here we're running out of now helium is like one is like one of the most common ingredients in the universe, but as we said in an earlier segment, helium, if it's in our atmosphere,

migrates to the top of the atmosphere and escapes into space. Right. In the old days, the Macy's Thanksgiving Day Parade, with the helium balloons, they would release the helium

back into the air and refill it every year. They don't do that anymore. No, they keep it now. They re-canister that. Macy's Day Parade, the second largest consumer of helium in the world after the U.S. government. And children at parties who want to talk funny.

Talk like Mickey Mouse. So, if you add it all up, I don't know how, I wouldn't know how to say that. But it's maybe quadrillion. I mean, if there's a number, a quadrillion is a thousand times bigger than a trillion. If I had to pick a number, I'd say a quadrillion dollars. So what is earth worth to somebody else who wanted Rinaldo? But here's the problem. Some of the value of those minerals

is because they're rare. If you call in an asteroid that is rich in gold, platinum, iridium, then the price that you are now trading it at on Earth... Will plummet. Will plummet. And then it's a whole other valuation. Right. So if you're worried about aliens taking our resources and you want to, like, charge them for it

in a swap of currency, I don't know that that's going to matter because on the route here from their home planet, they're going to pass asteroids. That they'll be able to mine for all the things that we find rare in fact they won't have to mine just hold the whole thing hold the damn thing in right take a bite out of it it was sitting there on the ground right no drilling no shipping just there it is so the value of resources is as you know if you're a stockbroker into into economics at all, is a function of not only the demand, but the supply.

And the cost of acquiring it wherever it happens to be. So it's a quadrillion dollars to us. Right. But to aliens... We're worthless. Food stamps. Food stamps. Here you go. So thanks, Magic.

Thank you so much, Doctor. All right. Thanks for checking in. Okay. That was a lot of fun. What else you got? Okay. This is a little geologist oriented. Then I'll get to say I have no clue.

Okay. Go on. But let me go. What is the furthest limit of the fossil and tectonic record? And what is known about how much further back the Earth supported a stable crust and life? I have heard... Okay, Earth has never had a stable crust. Just look around.

Whoa. No, it's churning daily. That's why we have earthquakes. Right. Go look at the USGS earthquake page on the internet, and it's a record of all the earthquakes in the world. They're like hundreds a day. Every day.

Every day. Every day there's earthquakes. Every day. The only ones you hear about are the ones that shake and bake a city. Right. But there are tremors. There are, you know, level two, three, four, and five. New York City had one last year, for goodness sake.

Okay? Not big enough to topple buildings. And that was based in Virginia, I think it was. And it was very widespread. It was. That's right. The energy was spread out. So it thinned out the energy.

So that's why, you know, there was no real disasters from that earthquake. So we've never had a stable crust. A, it's still not stable, and it will remain unstable for a long time to come. B, C, the earliest fossil evidence of life goes back, if you push it, if you really push it, 3.7, 3.8 billion years. 3.8 billion years. Yeah, these are single-celled organisms. Single-celled organisms. That's correct.

And here's what happens. If you wait long enough, the landmass that you're on subducts beneath other landmasses and rejoins the mantle and comes back out as a volcano, as lava. So Earth remakes its surface over several billion years. So that's why the oldest rocks on Earth are not as old as the oldest rocks on the moon. Exactly. Because the moon was done with its volcanic activity very early. And once you're done, your rock sits there.

You're not remaking yourself. You're not remaking yourself. You're just sitting there. You're just sitting there. But the Earth is kind of like our skin. Is that what you're saying? I guess, you know, if you're metrosexual and you get skin peels and things,

fine. It's not my first thought, Chuck. Groomed Chuck. It's not my first thought, but yes, you're constantly remaking your outer epidermis. Yes. Okay. I love that that's where my mind goes to my next chemical peel. All right, that was fast.

Next one. We've got like a minute. We've got a minute? Okay, let me find something. In this segment. Very quick. Which will happen first, the expansion of the sun into a red giant or the death of the dynamo inside the earth leading to the loss of the earth's magnetic field? Oh, we'll probably lose our dynamo before the death of the earth, is what I'm saying.

Dynamo is lingo for the movement of molten iron. And when you move metals, what you can do is you can end up generating currents. And if you have a current, you also have a magnetic field. And this is what a dynamo is. It's the relationship between sort of moving electrons and the magnetic field that comes about as a result. By the way, that's how we create electricity to begin with. That's right.

All right. We take wires, move it through a magnetic field. It works both ways. Moving current makes magnetic field and magnetic field can induce a current to make electricity we got a break when we come back more of StarTalk Radio. You can find us on the net, startalkradio.net. All our archive shows are there. We might have put the first season under wraps, but after that, they're available to you.

Excellent. Yeah, and check it out. There's quite a bit of interesting shows from our archive. Absolutely. That's the voice of Chuck Nice you're hearing, and he's reading me Cosmic Queries. I've never seen these. They come in on all of our social media portals. That's correct.

And give it to me. And the topic today is Earth. And I'm an astrophysicist, so to me it would be Earth as a planet, not Earth as a geologist. There you go. All right. So here we go. Let's move on to an email question. This is by Bud Sant.

Oh, wait, wait. In a previous segment, someone asked what would happen to life if the Earth's magnetic field changed? That's right. We lost our dynamo. I forgot to say we have evidence that the magnetic field has gone away many times before. Oh. Because it goes to zero as it flips. Our magnetic field has flipped many times in the past.

It's flipped. Okay, so it's happened then. And so when it's flipped, it goes to zero. You can look at the fossil record. While we had zero magnetic field, Karen and I are making babies just fine. So whatever is their version of a baby is just fine. It's just fine. So it does not appear to be as severe as you might think.

Okay. The evidence shows. That's good to know. Yeah. All right. So what else you got? This is an email by Bud Sant, and Bud wants to know this. How does the northern hemisphere's high proportion of land mass affect the Earth's rotation?

Ooh. Yeah. So here, the, what's the fellow's name? This is Bud Sant. Bud knows that most of the land of the earth is in the northern hemisphere. It's like 80% of the land is in the northern hemisphere. And by the way, about 80% of the population, the human population is in the northern hemisphere as well.

Right. So we tend to live where the land is. Help us, Aquaman. Just an FYI on that one. So Earth has a rotation rate that is endowed by the distribution of matter on our surface and throughout the solid ball. All right. by the distribution of matter on our surface and throughout the solid ball, all right? If you were to change the distribution of matter, if you were to move continents from the northern hemisphere into the south

towards the equator, away from the equator, you will change what's called the moment of inertia of the Earth. The moment of inertia of the Earth. It's a physics term. If you change the moment of inertia, Earth rotation rate will change with it. Okay.

And by the way, skaters do this. When they pull their arms in, they are changing their own moment of inertia. And what happens to their rotation rate? They go faster and faster. They go faster. And by the way, how do they stop? They put their arms out. Back out, and they can stop on a dime. Right.

Right? They change their rotation rate by bringing their arms in or out. If you move continents towards the equator, away from the equator, into the southern hemisphere, towards the northern hemisphere, you are changing the moment of inertia. Our rotation rate will change. And you can calculate how much we change after every earthquake because an earthquake is a redistribution of the continental shelf. Wow.

Yeah. And so we would actually change our days and nights and everything. The length of the day. You can make it longer or shorter. Longer or shorter depending on the moment of inertia change. Exactly. In fact, melting glaciers changes the rotation rate of the Earth. What?

Yep. Because you have mass in one location and then it melts and moves to another location on Earth. Got you. Yeah. Awesome. Wow, man. They also change the rotation rate because the glaciers location on Earth. Got you. Yeah. Awesome. Wow, man. They also change the rotation rate because the glaciers are on land. And so not only will the mass redistribute, it also moves from high altitude to sea level.

To sea level. Okay. So now you're changing how far away the matter is from the rotation axis of the Earth. All this conspires to influence our rotation rate. You know what? I got to tell you, I never thought you would give that much information from that question.

That is awesome. Yeah, you got it. All right, let's move on. Let's go back to Facebook. Okay. And this is Brian Engel from Facebook. If the moon is constantly getting farther away from the Earth every year. About two inches a year.

Okay, so about two inches a year. Then why do we have a super moon where the moon appears larger? Okay, first I got to nip this in the bud. Okay. Don't get me started. I'm getting you started. Don't get me started. I got to get you started here.

All right, so there's something called a super moon. Okay. I don't know who first called it a super moon. All right. I don't know. But if you have a 16-inch pizza, would you call that a super pizza compared with a 15-inch pizza? How many meat toppings are we talking? Because if we're talking like totally loaded, then yes.

I'm going with yes. And is there cheese in the crust? Right. If there's cheese in the crust, then come on. The Supermoon is a 16-inch pizza compared with a 15-inch pizza. It's a slightly bigger moon. I ain't using the adjective super. Supermoon.

Excuse me. That's like Super Tuscan. I'm not going there. Super Tuscan wines. Right. Yes. Yes, they're super because they're super priced. They cost like four or five times regular.

You pay like $ hundred bucks to... All right. So where was I before? Why don't you talk about wine? I'm talking about the universe here. I'm sorry. Bring up Tuscan wine. You know, what can I say?

I'm always thinking about wine. So there is no super moon. So the super moon is... The moon's orbit around the earth is not a perfect circle. Sometimes it's closer. Sometimes it's farther away. Gotcha.

At every month, there's a moment when it's closest. Gotcha. Occasionally, that moment when it's closest coincides with a full moon. People are calling that a super moon. I got it. But there's super half moons, right? There's not every month. Every month.

So one of those phases is the closest. I don't hear people, oh, super crescent, super half moon, super No! No! Don't get, I told you, don't get me started. Not only that, I was going to tweet this, but I'm going to say it here now first. You ready? Do you know, the full moon has no higher tidal

effect on Earth than any other phase of the moon? Now you're just making stuff up. Alright, when we come back, more StarTalk Cosmic Queries. We're back. Star Talk. Cosmic Queries Edition.

We're themed today with questions on the Earth. Yes. Now, do I look like an Earth expert to you? You know, I got to tell you, as long as I've known you, I don't know pretty much anything you're not an expert on, seriously. I'm serious when I say I'm not even blowing smoke. Somehow our producers thought we would have a – wouldn't it be nice if we had Earth questions? So I can answer Earth questions, Earth as a planet, not Earth as a geologist.

Right. Hey, before we go further, I just – because I need you to clear something up, man. What? I'm serious, Neil. What? Okay. You said that there's no effect that the moon has on the tidals. I mean a bigger full moon. Sorry, let me say this again.

You said there's no effect a full moon has on the tides than any other moon. That's correct. And you couldn't let it go? You couldn't? No, because when Sandy came, I believe you, but I'm just saying, there's a lot of people out there who's going to have a problem with this, because the news when Sandy happened, Hurricane Sandy, they talked all about the tidal effects of the moon and it was a full moon okay this is

why sandy was so there are only two things that affect the tides from the moon you ready go ahead the mass of the moon is that changing that never changes okay is the mass of the moon higher at full moon than at half moon no it's the same moon a b the distance to the moon of the moon higher at full moon than at half moon? No, it's the same moon. A. B. The distance to the moon. Okay? Right. The moon orbits us. Sometimes it's closer. Sometimes it's farther away.

That has nothing to do with the phase. Right. It's an elliptical orbit. Sometimes it's closest to full moon. Sometimes it's not. But it's not. Okay? Right.

Those are the only two things that affect the strength of the tides on Earth from the moon. Okay. So why do we have a higher tide during full moon? Because the sun's tides add to the full moon's tide. I got you. To the moon's tide. So it's the sun. It's the sun.

Blame the sun. Blame the sun. Blame Sandy on the sun, not the poor moon that dutifully orbits us every month of the year. Fantastic. Don't blame the moon on that one. What's next? Okay. Well, we have a phone call.

We got a phone call. And we have Blake, who I believe is a soldier at Fort Bragg. Ooh. Yes. Is this Blake on the line? Yes, it is, Dr. Tyson. Blake, you call me doctor. I got to call you by your title.

What are you? War Officer One. One Officer One. One Officer One? Mister. Mister. Oh, okay. Okay. No, no. He said yes. Okay. one officer one one officer one mister mister oh okay no no he said yes sir okay so Blake what do you have for me and call me

Neil please please yes sir Neil these military guys you can't get the sir out of them that's great alright so what do you have my question has to do with the gravity of the earth if the earth had been born with twice the size, it would have twice the gravity,

and anything that evolved on the planet would have evolved in that double-time gravity that we currently have. Is there any upper limit to an Earth-like planet where carbon-based life forms just wouldn't have been able to evolve because of the massive gravity? That's a brilliant question. It really is. It is. It is. So a couple of things. If Earth were sort of twice our size, we would have eight times the mass, okay, because the

volume goes up as the cube of the thing. So that's two cubed would give you eight. Right. So the surface gravity then is a combination of how much farther away we are from the center of the Earth and how much extra mass is there. So you can do the math, but you can just assert. Make an Earth that has twice the gravity. Here's what will happen. Everybody's legs would be more squat.

First of all, okay? So everyone would look a little bit more like a hippopotamus, all right? Or dwarf. Or dwarfs Right Things wouldn't grow as tall Giraffes would have Thicker legs Horses would be shorter

All of that would happen Okay The giraffe has Very high blood pressure To get blood to its brain To go up to all The vertebrae of its neck And so

If you have twice the gravity You would need Twice the pressure To get it up there And that could blow your blood vessels. So you'd have shorter giraffes. So you wouldn't have any of these tall creatures. But you didn't ask about mammals.

You asked about carbon-based life. Most of the biomass on Earth could care less, couldn't care less what the force of gravity was on Earth, period. All the life in the force of gravity was on Earth. Period. All the life in the ocean is neutrally buoyant. That's right. It doesn't care. Bacteria swimming in the pond.

In the pond drop. You know, when you look at it in school, you look at the... Oh, the petri dish? You get a drop of water from the pond and you see paramecium in it thriving? Yes, yes. They don't care about gravity. That's right. Their lives, they thrive under the surface tension of the water. So most life actually does not care about gravity.

We do because we're out here on the land. We're out here on the land. We're trying to jump. Olympics would be kind of different. There'd be no hurtling. No. There'd be the low hurdles. Low hurdles.

High hurdles. So, yeah. So, sports would be very different. But a factor of two gravity, not a problem for life. Right. And you'd have sort of more sort of smaller life thriving than bigger life. And that's about it. Wow.

Yeah. There you go, Blake. So, thanks, Blake, for that one. Thank you very much. All right. You're listening to StarTalk Radio, the Cosmic Queries edition. Today's topic, the Earth.

We'll see you in a moment. This is StarTalk Radio. The lightning round. Chuck, you know what the rules are. Oh, yeah. You're going to read me questions. Rapid fire. I'm going to give you soundbite answers. I haven't heard the questions before.

That's correct. And we invented the lightning round because we never got through all the questions. Right, so this is a way of getting to everybody's questions. Just one follow-up on that last bit from the soldier at Fort Bragg. He had asked about doubling Earth's gravity. And I said, ocean life wouldn't care.

But I should have commented, water then weighs twice as much. So, if you're accustomed to swimming at a particular depth, you then swim at half that depth. Gotcha. That way the weight of the water above you would be the same as it was in the previous earth. Right. Right, that's all.

Okay. I just want to straighten that out. Okay, okay. And they could easily find that place, right? They're fishes and they move in three dimensions. Exactly. There you go. Right.

All right. All right, lightning round. Let's do this. I have a bell. Where's your bell? Let's get it out. Here it is. There's the bell. All right, here we go. Are we ready? Yes. All right. Lightning round. Let's do this. I have a bell. Where's your bell? Let's get it out. Here it is. There's the bell.

All right. Here we go. Are we ready? Yes. All right. Let me test it. Yep. There we go.

Okay. We're good to go. This is from Justin Keeney. How large would an object have to be to impact the Earth and alter its orbit around the sun? I'm going to change that to, is there an object large enough to do that? Anything that hits Earth alters our orbit. The question is, is it altering it in any significant way? There is nothing on a collision course

that will have any significant impact on Earth's orbit around the sun. And odd that he's worried about our orbit around the sun and not on our survival from such a collision. Yeah, because such a collision will wipe us out. You'll go extinct and Earth's orbit will be just fine. There you go. All right. Oh, by the a collision will wipe us out. You'll go extinct and Earth's orbit will be just fine. There you go. All right.

Oh, by the way, in the early solar system, there was such stuff that would have knocked our orbit well out of whack. But all that's been absorbed up and vacuumed up by all the other planets, and we are in a mature-looking solar system. Hey, thanks, Jupiter, for taking one for the team. Taking one for the team. You got it. Jupiter ate most of it. There you go. Leon Bruce wants to know this.

If we continue to leave scraps, debris in space from our satellites and such, would we ever develop a ring such as Saturn? A debris ring. A debris ring. So the low-hanging debris will reenter Earth's atmosphere because it'll get friction from the air. If it's very high up, it'll never go away ever. And we already have a ring of debris. It's at the 22,000 miles up where we put the communication satellites. They're in a ring over the equator of the Earth, so we already have rings.

Well, we already have a ring. Yeah, yeah. It's not big enough like Saturn's rings, but if we kept at it, because when a satellite dies, we just lift it up a little higher, and to make room for another satellite to take it away. So would you keep this up? So there's a bunch of dead satellites floating above us. Dead satellites too far away

to re-enter the atmosphere, and they just stay there forever. Forever. Yes, we are creating our own Saturnian ring around the Earth's system. Nice! Nice! Okay, Susan Hammock wants to know this. I know that atmospheric pollution contributes to the colors we see in the sunset and sunrise. What would those sunsets and sunrises look like during prehistoric times with no man-made pollution? Would they still have been red and orange?

First of all, women are making pollution too. So don't be blaming men for that. A. B. It's not only pollution. It's pollen. It's water vapor. It's dust kicked up from deserts.

All kinds of particles. It's volcanic particles. All those particles make a sunset red because all the colors from the sun are red, orange, yellow, green, blue, violet. Mix them together. It is white light. Right. Those particles scatter out of the sunbeam all the colors from the sun are red, orange, yellow, green, blue, violet. Mix them together, it is white light. Right. Those particles scatter out of the sunbeam all the blue.

That's why we have a blue sky. Right. And the more it scatters, the deeper the yellow, orange, red, the sun appears so that when you have maximal scattering, that's right at sunset when the sun is deepest red and the sky is deepest blue. So dinosaurs would have totally enjoyed red sunsets in their day without the benefit of our pollution. So red sunsets, just breathing easier. That's right, exactly.

There you go. Awesome. All right. Let's move on to Felipe Santiago. Felipe wants to know this. Could a cataclysm like the one that destroyed Krypton occur in reality? Can a planet explode from within?

And what would be the reason? We're talking about Superman's home planet. Krypton. Okay. If we remember from the film, they overmined the planet, made the core unstable, and then the planet collapsed and then exploded. Correct. We are not overmining our planet to destabilize the planet made the core unstable and then the planet collapsed and then exploded. Correct. We are not over mining our planet to destabilize the planet.

We're over mining our planet to destabilize our atmosphere. That's different. So no, we're nowhere close to that ever happening here on Earth. But if you start taking whole chunks of the inside of the Earth out, yeah, you're going to start collapsing. You're going to have some serious sinkholes on your hand. Will we explode? No. The energy isn't enough to explode the earth

and have us scatter into space. So the answer is we won't explode, but there's still hope for the cataclysm. All right, next. Let's... All right. Quick. Okay, here we go.

One minute, go. Here we go, one minute. All right, here we go. Mike McGill wants to know this. What's the most unexpected and less well-known danger we are exposed to as a planet from the cosmos? Ooh. Well, in the year 1900, you ask people, what are you most worried about? They're worried about overpopulation and lack of food and all of this. They were not worried about asteroids. So true.

They didn't learn about asteroids yet. And we know about them. Now we know about them so I ask myself there's the known knowns and how about the unknown unknowns in a century what will people

be listing as the biggest risk to their lives we have no idea that's why it's good to kind of learn what's out there

don't be saying oh I'm just looking at earth that's all I care about no because the end of your life may come from space learn something dummy we gotta go this has been Star Talk Cosmic Queries Edition Earth, that's all I care about. No, because the end of your life may come from space. Learn something, dummy.

We gotta go. This has been StarTalk Cosmic Queries Edition. Chuck Nice, thanks as always for being my co-host here. My pleasure. I'm Neil deGrasse Tyson, your personal astrophysicist, thanking the National Science Foundation for their support, in part, for the production of this program.

As always, I bid you to keep looking up.