Latest / Daniel and Kelly’s Extraordinary Universe / Can we defend the Earth from deadly space rocks?

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Can we defend the Earth from deadly space rocks? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, Kelly, do you guys get really nice dark skies
• 0:11
  Speaker 1: out there on the science Farm. Yeah, we totally do.
• 0:14
  Speaker 1: We're far enough away from civilization that we get really
• 0:17
  Speaker 1: awesome dark skies at night. Oh that's so nice. So
• 0:21
  Speaker 1: what kinds of things your kids like to see up
• 0:23
  Speaker 1: in the dark skies? Well, we've got this app and
• 0:25
  Speaker 1: we like to try to figure out where the I S.
• 0:28
  Speaker 1: S is, but usually we miss it. And so what
• 0:31
  Speaker 1: we do get lucky and see sometimes that they love
• 0:34
  Speaker 1: is shooting stars, which, like, of course, because all kids
• 0:36
  Speaker 1: love seeing shooting stars. I find that kind of amazing.
• 0:39
  Speaker 1: What shooting stars? No, it's amazing to me that kids
• 0:42
  Speaker 1: like shooting stars. What's not to like? I don't know
• 0:45
  Speaker 1: the part where you explain to them how each one
• 0:48
  Speaker 1: is like a huge flaming bulletz screaming across the cosmos
• 0:51
  Speaker 1: that could land anywhere on Earth, devastating people. I like
• 0:55
  Speaker 1: to keep the level of existential dread and the family
• 0:58
  Speaker 1: to like a minimum. And so you're officially never invited
• 1:02
  Speaker 1: to come look at the night sky with my family.
• 1:05
  Speaker 1: Sounds like your family can't handle the truth, at least
• 1:08
  Speaker 1: about shooting stars. Hi, I'm Daniel, I'm a particle of
• 1:26
  Speaker 1: physicist and a professor at UC Irvine, and every shooting
• 1:30
  Speaker 1: star makes me nervous. Hello, I'm Kelly Wainer Smith. I'm
• 1:34
  Speaker 1: a parasitologist and adjunked with Rice University, and shooting stars
• 1:38
  Speaker 1: don't make me nervous unless I'm talking to Daniel and
• 1:40
  Speaker 1: he's ruining them for me. And that's the job of physics,
• 1:45
  Speaker 1: ruining everything. Since right, that's right, that's right. Well, we joked,
• 1:51
  Speaker 1: But the job of physics is to tell us the
• 1:54
  Speaker 1: truth about the universe. Who reveals to us exactly the
• 1:57
  Speaker 1: nature of the cosmos that we live in? And so
• 2:00
  Speaker 1: welcome to the podcast Daniel and Jorge Explain the Universe,
• 2:04
  Speaker 1: a production of I Heart Radio in which we talk
• 2:07
  Speaker 1: about exactly what is out there in the universe, what's
• 2:11
  Speaker 1: going on beyond the borders of our atmosphere, outpassed the
• 2:14
  Speaker 1: Solar system, outpassed even the edge of our galaxy, into
• 2:18
  Speaker 1: the deepest mysteries of the cosmos. Where did it all
• 2:21
  Speaker 1: come from, how does it all work, what's going to happen?
• 2:23
  Speaker 1: And will we survive it? My usual co host Org
• 2:26
  Speaker 1: is on a break today, so we are very happy
• 2:28
  Speaker 1: to be chatting with Kelly, who apparently doesn't worry about
• 2:31
  Speaker 1: death from above at all. Well, you know, I guess
• 2:34
  Speaker 1: I worry about it. No, you're right, I don't think
• 2:37
  Speaker 1: about it too much unless I'm talking to my physicist friends,
• 2:40
  Speaker 1: or unless I'm I'm talking to people who are thinking
• 2:42
  Speaker 1: about trying to mind the asteroids, which requires being able
• 2:45
  Speaker 1: to move them. That makes me nervous. But I can
• 2:48
  Speaker 1: just look up at the night sky and enjoy it
• 2:50
  Speaker 1: and not think too hard about it. On the other hand,
• 2:53
  Speaker 1: I can't look at sushi without overthinking it as a parasitologist.
• 2:56
  Speaker 1: So we all have our blind spots, or the spots
• 2:59
  Speaker 1: where we too hard. Unless it's really old, sushi is
• 3:02
  Speaker 1: unlikely to blow up in your face or cause a fireball. Yeah, no,
• 3:05
  Speaker 1: you're You're probably pretty safe from those particulars. But somehow
• 3:10
  Speaker 1: growing up and being an adult in this universe means
• 3:13
  Speaker 1: understanding just how crazy and dangerous and chaotic the universe is.
• 3:17
  Speaker 1: Just like when you learn that every surface is covered
• 3:20
  Speaker 1: in microoves of some kind. Now we are learning that
• 3:23
  Speaker 1: our spaceship Earth is also constantly bombarded with rocks from space.
• 3:29
  Speaker 1: So do you remember the first time you looked at
• 3:32
  Speaker 1: a shooting star and thought, oh, that could be bad
• 3:35
  Speaker 1: as opposed to like, were you a child with wonder
• 3:38
  Speaker 1: in your heart, Daniel, or were you born a physicist? Well,
• 3:40
  Speaker 1: you know, I was a child with wonder in my heart.
• 3:42
  Speaker 1: And then my father told me that those shooting stars
• 3:45
  Speaker 1: are actually rocks from space that are hurtling towards us,
• 3:49
  Speaker 1: burning up in the atmosphere, and sometimes they actually land
• 3:52
  Speaker 1: and explode. Is there one in particular that you heard
• 3:55
  Speaker 1: about that that made you nervous about this that you remember? Well,
• 3:58
  Speaker 1: I grew up part of the time in Arizona, and
• 3:59
  Speaker 1: so we visited Meteor Crater, and so we had a
• 4:02
  Speaker 1: very like visceral example of how rocks from space really
• 4:06
  Speaker 1: can come all the way down to the surface and
• 4:08
  Speaker 1: create huge explosions, which leaves DNS in the Earth's surface
• 4:12
  Speaker 1: for thousands or millions of years. And do you remember
• 4:15
  Speaker 1: like having a profound moment of oh, shoot when you
• 4:18
  Speaker 1: looked at that. I do, and ever since then, when
• 4:20
  Speaker 1: I look at shooting stars, I'm wondering, like, who's that
• 4:23
  Speaker 1: one going to hit? You know, It's sort of like
• 4:25
  Speaker 1: we're in a shooting gallery and we're like, oh, look
• 4:27
  Speaker 1: at all the fancy bullets. See that's funny. Like I think,
• 4:31
  Speaker 1: for the at least the first twenty years of my life,
• 4:33
  Speaker 1: I lived in this amazing state of complete oblivion, and
• 4:36
  Speaker 1: so you know, like, for example, in preparation for this episode,
• 4:39
  Speaker 1: I was looking up some comment impacts that happened in
• 4:42
  Speaker 1: the past, and I don't remember hearing anything about Shoemaker Levy,
• 4:45
  Speaker 1: for example, do you remember when that hit? I do
• 4:48
  Speaker 1: remember Shemaker Levy because I was doing one of my
• 4:51
  Speaker 1: first research internships that summer and the guy I worked
• 4:55
  Speaker 1: with had a super high speed camera and a telescope,
• 4:57
  Speaker 1: so we actually hooked up his high speed plasma imaging
• 5:00
  Speaker 1: camera to a tels Go hoping to take pictures of
• 5:03
  Speaker 1: the fireballs when they erupted off of Jupiter. So yeah,
• 5:07
  Speaker 1: I was definitely very aware of that. I was excited.
• 5:09
  Speaker 1: I was like, yeah, let's blow up Jupiter and did
• 5:11
  Speaker 1: you get the footage that you all wanted? We didn't
• 5:13
  Speaker 1: actually because the night we were observing she Maker Levey
• 5:16
  Speaker 1: hit on the back side of Jupiter, so we didn't
• 5:18
  Speaker 1: actually get to see it. So I don't even remember
• 5:21
  Speaker 1: that it hit on the back side. But it was
• 5:22
  Speaker 1: also a funny lesson in early days of science communication
• 5:25
  Speaker 1: on the NASA website because when Shoemaker Levy came into
• 5:28
  Speaker 1: the Solar System, it got broken up by title forces.
• 5:31
  Speaker 1: So it wasn't just like one big comment. It was
• 5:33
  Speaker 1: this train of comets, like twenty three or twenty four
• 5:36
  Speaker 1: of them, and so of course astronomers named them A, B, C, D, etcetera.
• 5:41
  Speaker 1: So boring. Yeah, And then when the first one hit Jupiter,
• 5:44
  Speaker 1: they called that the A spot, and then when the
• 5:47
  Speaker 1: second one hit Jupiter, they called that the B spot.
• 5:50
  Speaker 1: And it wasn't until I think they got to F
• 5:52
  Speaker 1: that they realized what are we gonna call where the
• 5:55
  Speaker 1: G one hits? And so on the NASA website there
• 5:59
  Speaker 1: was like pictures of F spot and then the G
• 6:01
  Speaker 1: impact site and then the H spot. You got to
• 6:06
  Speaker 1: think these things through all the way before you name
• 6:09
  Speaker 1: it a spot, think about what happens. Anyway, this was
• 6:12
  Speaker 1: very visceral to me, and it made me realize, like, wow,
• 6:14
  Speaker 1: space really is not empty. Space is filled with stuff.
• 6:18
  Speaker 1: And this is something we've been talking about on the
• 6:20
  Speaker 1: podcast for a while, not just that space has huge
• 6:23
  Speaker 1: rocks that might end human civilization, but space is not empty.
• 6:26
  Speaker 1: On lots and lots of levels, you know from like
• 6:29
  Speaker 1: tiny particles, the solar wind is a huge stream of
• 6:32
  Speaker 1: protons and electrons that are put out by the Sun.
• 6:35
  Speaker 1: It doesn't just make light. And we've talked on the
• 6:38
  Speaker 1: program a lot about neutrinos. The Sun pumps out zillions
• 6:41
  Speaker 1: and zillions of neutrinos. So even from the particle point
• 6:45
  Speaker 1: of view, if you go out into space, you're inundated
• 6:48
  Speaker 1: with radiation. And then take a step up to like
• 6:51
  Speaker 1: micro meteorites, you fly spaceship or spend time on the
• 6:54
  Speaker 1: I s S, you have to really worry about your
• 6:55
  Speaker 1: little life bubble getting hold by one of these high
• 6:58
  Speaker 1: speed moving pebbles. Well, yeah, then you gotta worry about
• 7:01
  Speaker 1: the new trinos too, right, Didn't those cause the Carrington
• 7:04
  Speaker 1: event on Earth? So sometimes they those cause problems down
• 7:07
  Speaker 1: on Earth as well. The solar wind definitely causes problems
• 7:10
  Speaker 1: on Earth. It can fry satellites and in cases of
• 7:12
  Speaker 1: really big coronal mass ejections, it can also make like
• 7:15
  Speaker 1: telephone and electrical wires spark here on Earth. It's not
• 7:19
  Speaker 1: due to the new trinos. Those interact so weakly that
• 7:22
  Speaker 1: they can pass through like a light year of lead
• 7:24
  Speaker 1: without having any effect. But the high energy, electrons and
• 7:27
  Speaker 1: protons and photons from one of those events can really
• 7:30
  Speaker 1: cause damage here on Earth. We actually had a whole
• 7:33
  Speaker 1: episode about just what to do if that happens. But
• 7:36
  Speaker 1: space is filled with this stuff, right, It's not like
• 7:38
  Speaker 1: when you go out there, it's just total emptiness. It's
• 7:41
  Speaker 1: not actually that's safe out there in space. It's sort
• 7:44
  Speaker 1: of contrary to what I think a lot of people's
• 7:46
  Speaker 1: view of spaces in their mind's eye. But so like
• 7:49
  Speaker 1: when I was younger, I watched a lot of movies,
• 7:52
  Speaker 1: like I watched Was It Armageddon with Bruce Willis and
• 7:56
  Speaker 1: Ben Affleck, And so I'm pretty sure that any of
• 8:00
  Speaker 1: these space based problems we can probably figure out. Well.
• 8:05
  Speaker 1: It's interesting also to see how Hollywood reacts to science.
• 8:09
  Speaker 1: You know, when Shoemaker Levey came into the Solar System,
• 8:11
  Speaker 1: it was a wake up call for the human race,
• 8:14
  Speaker 1: for NASA, for scientists, for everybody. Until then, people hadn't
• 8:18
  Speaker 1: really understood the dangers of these comments. You know, it
• 8:21
  Speaker 1: wasn't until like the mid sixties that we understood that
• 8:25
  Speaker 1: the surface of the Moon had craters because there were
• 8:28
  Speaker 1: so many impactors, And it wasn't until a few decades
• 8:31
  Speaker 1: ago that we understood that, you know, the dinosaurs had
• 8:33
  Speaker 1: been wiped out by a large impactor, But it was
• 8:35
  Speaker 1: Shoemaker Levy that made it real that main people think,
• 8:38
  Speaker 1: oh my gosh, this just happened to our neighbor Jupiter,
• 8:41
  Speaker 1: it could also happen to us. And that's when NASA's
• 8:45
  Speaker 1: like planetary protection program really took off. And that's when
• 8:49
  Speaker 1: Hollywood realized, oh, here's a whole new topic for a movie.
• 8:53
  Speaker 1: And that's why you got two big movies What was
• 8:55
  Speaker 1: at Armageddon and Deep Impact that came out like in
• 8:58
  Speaker 1: the same year about the same top because there was
• 9:01
  Speaker 1: this sort of human awakening of the danger. So based
• 9:04
  Speaker 1: on our timing of awakening to this danger, didn't the
• 9:06
  Speaker 1: hypothesis that an asteroid killed the dinosaurs? Didn't that predate
• 9:10
  Speaker 1: Shoemaker Levee or were we just not quite sure about
• 9:13
  Speaker 1: it at that point that predated Shoemaker Levee. But you
• 9:15
  Speaker 1: know that was sixty five million years ago. Well, I mean,
• 9:18
  Speaker 1: our our understanding of it as a problem, right exactly,
• 9:21
  Speaker 1: But we understood that it was so long ago it's
• 9:23
  Speaker 1: probably a really rare event might come every few million years,
• 9:27
  Speaker 1: not something we have to worry about. But Shoemaker Levee
• 9:30
  Speaker 1: happening like right now basically means that's not that uncommon.
• 9:34
  Speaker 1: It might be that their commentary impact every few decades
• 9:37
  Speaker 1: in the solar system or every hundred years. It's much
• 9:40
  Speaker 1: more immediate than this like ancient thing that happened a
• 9:44
  Speaker 1: long long time ago. And I think that really brought
• 9:46
  Speaker 1: the danger into focus for people. So if I had
• 9:48
  Speaker 1: to guess, like, so, I know, Hollywood has made it
• 9:51
  Speaker 1: seem like, you know, maybe sometimes we can solve these problems,
• 9:54
  Speaker 1: But based on how humans are dealing with the risk
• 9:56
  Speaker 1: of climate change, I'm going to guess that we're also
• 9:59
  Speaker 1: not doing much to deal with the risk of risk
• 10:01
  Speaker 1: of asteroids. Is that about right? Are we just sort
• 10:04
  Speaker 1: of crossing our fingers and hoping it will work out?
• 10:08
  Speaker 1: I'm guessing you watch don't look up recently, and I
• 10:11
  Speaker 1: didn't make you enthusiastic about human about humanity's ability to
• 10:15
  Speaker 1: confront existential crises. I'm not sure it was optimistic before,
• 10:18
  Speaker 1: but yeah, you're right, the movie didn't help too much. Well,
• 10:22
  Speaker 1: there is a lot of conversation about whether that movie
• 10:24
  Speaker 1: is about climate change or actually about an asteroid impactor,
• 10:27
  Speaker 1: But you might actually be pleased to learn that since
• 10:30
  Speaker 1: that day, humanity really has woken up to the danger
• 10:32
  Speaker 1: and there's a broad and vigorous effort to figure out
• 10:36
  Speaker 1: where these rocks are, how much danger we're in, and
• 10:38
  Speaker 1: try to do something about it. Oh, let's talk about that.
• 10:42
  Speaker 1: Side note. I think that just yesterday there was news
• 10:45
  Speaker 1: that an asteroid we had discovered two hours earlier that
• 10:48
  Speaker 1: was pretty big, was about two hits, which doesn't make
• 10:51
  Speaker 1: me feel like we're as on top of it as
• 10:53
  Speaker 1: maybe i'd like. Yeah, there are definitely some holes in
• 10:55
  Speaker 1: our protection system, and so we'll dig into in detail,
• 10:58
  Speaker 1: and on today's episode we'll be asking the question can
• 11:06
  Speaker 1: we defend Earth from deadly space rocks? Subtitle Does Kelly
• 11:11
  Speaker 1: need to tell her kids the truth? Kelly will not
• 11:16
  Speaker 1: be doing that. The pandemic has been enough of an
• 11:18
  Speaker 1: existential threat. Maybe when they're eighteen. Are you saying that
• 11:21
  Speaker 1: your kids don't listen to the podcast? Is that what's
• 11:23
  Speaker 1: going on here? Oh? No, they definitely listen to the podcast,
• 11:26
  Speaker 1: but just maybe not this episode. I'll email your husband
• 11:32
  Speaker 1: a link to it. Then. So the idea is that
• 11:34
  Speaker 1: waking up to the crazy dangers of our solar system,
• 11:37
  Speaker 1: understanding that space is not empty, but filled with death
• 11:41
  Speaker 1: bullets that might impact us. There's not nothing that we
• 11:44
  Speaker 1: can do about it. We can actually wake up as
• 11:46
  Speaker 1: a species and try to confront this danger, and so
• 11:49
  Speaker 1: we thought it'd be fun to explore what we know
• 11:51
  Speaker 1: about these asteroids and comments how dangerous they actually are
• 11:54
  Speaker 1: and the status of the Earth Protection system. This is
• 11:57
  Speaker 1: an easy one. It's obviously to send versus this up
• 12:00
  Speaker 1: there with a reflect even if they don't want to
• 12:03
  Speaker 1: go send them up there. Well, there's no correct answer,
• 12:08
  Speaker 1: it's just what do you think is the best way.
• 12:09
  Speaker 1: I think it's a laser laser best way to break
• 12:14
  Speaker 1: up an incoming asteroid. I think would be too probably
• 12:20
  Speaker 1: not to blow up a nuclear weapon like an Armageddon,
• 12:24
  Speaker 1: so not to do it Bruce Wall's style, I would
• 12:26
  Speaker 1: say to send a spaceship that could give it a
• 12:31
  Speaker 1: slight nudge and then it could deviate slightly from its
• 12:34
  Speaker 1: original path and miss the Earth. I don't think there
• 12:38
  Speaker 1: really is a good way to break up an incoming asteroid,
• 12:42
  Speaker 1: especially as they can really vary on how solid they
• 12:48
  Speaker 1: truly are, one big glob of iron and rock or
• 12:52
  Speaker 1: a big old pile of pebbles, And if you don't
• 12:55
  Speaker 1: do it right, all the pieces still hit the Earth,
• 12:59
  Speaker 1: so you still get all of that energy into our atmosphere,
• 13:03
  Speaker 1: which is not a good thing for us. Far better
• 13:06
  Speaker 1: to just find the best way to move it, which
• 13:11
  Speaker 1: also will probably vary based on its makeup. The best
• 13:14
  Speaker 1: way to break up an incoming asteroid would be to
• 13:19
  Speaker 1: hit it with another one of similar size. I'm going
• 13:23
  Speaker 1: to take a page out of the war Games playbook
• 13:26
  Speaker 1: and guess that the best way to break up an
• 13:29
  Speaker 1: incoming asteroid is not to do so, because if you
• 13:32
  Speaker 1: do break it up, you have a bunch of fragments,
• 13:35
  Speaker 1: some of which may still hit Earth with enough mass
• 13:39
  Speaker 1: and velocity to be quite dangerous. And I assume that's
• 13:43
  Speaker 1: why you're trying to break one up in the first place.
• 13:46
  Speaker 1: If you really did have to break one up, though,
• 13:49
  Speaker 1: I would guess the best way would be too Drill
• 13:53
  Speaker 1: as deep a whole as you possibly can down to
• 13:57
  Speaker 1: the center. Anyway, insert a nuclear weapon or something like that,
• 14:04
  Speaker 1: and the blow that sucker up. The best way I
• 14:07
  Speaker 1: can put it is slowly, because if you blast an
• 14:12
  Speaker 1: asteroid it can turn into a lot more little pieces,
• 14:17
  Speaker 1: but that can still make significant damage. Now you have
• 14:21
  Speaker 1: ten problems to deal with instead of one. So I
• 14:24
  Speaker 1: don't know if it's like with kind of a laser
• 14:27
  Speaker 1: that isn't too powerful, too totally blasted, but kind of
• 14:33
  Speaker 1: too corroded away, so then you can maintain it as
• 14:37
  Speaker 1: one asteroid, but then keep it shape. Well, if you
• 14:39
  Speaker 1: could fling another asteroid at it and hit it like
• 14:41
  Speaker 1: a billiard ball and send it another direction, that'd be great.
• 14:46
  Speaker 1: It's my understanding. If you just blow it up, then
• 14:48
  Speaker 1: you have a bunch of little pieces raining down on
• 14:50
  Speaker 1: earth that might not be little enough. I don't think
• 14:53
  Speaker 1: you really want to break it up. I think you
• 14:55
  Speaker 1: want to push it off course, not break it up.
• 14:58
  Speaker 1: Then you just get told with a bunch of stuff.
• 15:01
  Speaker 1: So it seems like a common thread here is that
• 15:03
  Speaker 1: you don't want to blow up asteroids because you're gonna
• 15:06
  Speaker 1: cause more trouble that way, And it was it was
• 15:08
  Speaker 1: interesting to see that so many people that sort of
• 15:11
  Speaker 1: honed in on that theme, And to be honest, I
• 15:13
  Speaker 1: don't know if that's true or not. It maybe it
• 15:14
  Speaker 1: depends on how big your blast is and how far
• 15:17
  Speaker 1: away you are, but it does seem like everybody has
• 15:19
  Speaker 1: some idea of how to tackle this problem. In their
• 15:22
  Speaker 1: heads already, and I was happy to see that at
• 15:23
  Speaker 1: least one person had watched the movie that I had watched.
• 15:26
  Speaker 1: Is it Armygeddon with Bruce Willison Ben Affleck? Is that
• 15:28
  Speaker 1: what it was called? Don't we even remember which is
• 15:30
  Speaker 1: which anymore? You're probably right and probably seeing those two
• 15:33
  Speaker 1: movies is what everybody knows about asteroids and commentary impact.
• 15:37
  Speaker 1: That's probably the amount of research people have done. And
• 15:39
  Speaker 1: so we can thank Hollywood, I guess, for at least
• 15:42
  Speaker 1: educating the public about the dangers and maybe misleading them
• 15:47
  Speaker 1: about the possible solutions. That's how it always works, isn't it.
• 15:51
  Speaker 1: I wonder if they had legitimate science advisors on those movies.
• 15:54
  Speaker 1: I know these days they try to reach out to
• 15:56
  Speaker 1: experts in the field to consult, but back in the nineties,
• 15:59
  Speaker 1: I have the and they're probably just winging it. Yeah,
• 16:01
  Speaker 1: I think there's probably someone in it, and I think
• 16:03
  Speaker 1: even today they don't even always listen to their experts.
• 16:06
  Speaker 1: So you've you always got to be a little critical
• 16:07
  Speaker 1: when you're watching a movie. Okay, so where are these
• 16:10
  Speaker 1: things coming from? Could they be coming from anywhere in
• 16:12
  Speaker 1: space or do they tend to like start in certain areas,
• 16:16
  Speaker 1: and those are like more likely to produce deadly space rocks.
• 16:20
  Speaker 1: I think something that would surprise people is that most
• 16:23
  Speaker 1: of the deadly space rocks are basically our neighbors. If
• 16:26
  Speaker 1: our rock comes and hits the Earth, it's not likely
• 16:28
  Speaker 1: to be coming from like deep deep space, another solar system,
• 16:32
  Speaker 1: or somewhere else randomly in the galaxy. Instead, it's much
• 16:35
  Speaker 1: more likely to come from somewhere here in our Solar system.
• 16:38
  Speaker 1: And to understand why, you have to go back to
• 16:40
  Speaker 1: the very formation of the Solar system. Remember, before we
• 16:43
  Speaker 1: have our Sun and all of the planets, everything was
• 16:46
  Speaker 1: basically just a huge cloud of gas and dust, rocks,
• 16:50
  Speaker 1: bits left over from other solar systems that had burned
• 16:54
  Speaker 1: and made mistakes and made silly movies and lied to
• 16:57
  Speaker 1: their children about dangers. Hey pretended that Santa Claus and
• 17:02
  Speaker 1: the tooth ferry existed, all this kind of stuff, and
• 17:05
  Speaker 1: then you know, those solar systems came to an end,
• 17:07
  Speaker 1: and their debris was the fodder for our Solar system
• 17:10
  Speaker 1: to have this huge cloud of stuff which then gathers
• 17:13
  Speaker 1: together gravitationally. Most of it, of course, is still hydrogen,
• 17:17
  Speaker 1: because that's what was created in the big bang, and
• 17:19
  Speaker 1: fusion in the heart of stars has turned a little
• 17:21
  Speaker 1: bit into heavier elements, but still hydrogen is the dominant
• 17:24
  Speaker 1: thing in the universe, and so you get the Sun,
• 17:26
  Speaker 1: which has most of the hydrogen in the Solar System,
• 17:29
  Speaker 1: and then the formation of other stuff. You get the
• 17:31
  Speaker 1: planets where you get these like little gravitational seeds that
• 17:34
  Speaker 1: accrete other stuff. But not everything ends up inside a
• 17:37
  Speaker 1: sun or a planet, and that's why you have, for example,
• 17:40
  Speaker 1: the asteroid Belt, which is a huge collection of rocks
• 17:44
  Speaker 1: basically between Mars and Jupiter that never formed into a planet.
• 17:48
  Speaker 1: So how many potential Earth killing things are out there,
• 17:52
  Speaker 1: it's a great question. We aren't exactly sure because these
• 17:55
  Speaker 1: things are hard to see. Remember, asteroids are dark, they
• 17:59
  Speaker 1: don't glow like a star, So if you're going to
• 18:01
  Speaker 1: see one, you have to see it because life has
• 18:03
  Speaker 1: gone from the Sun, hit the asteroid and then bounce
• 18:06
  Speaker 1: back exactly into your telescope. So it's only when this
• 18:10
  Speaker 1: thing happens to reflect light right back to Earth that
• 18:13
  Speaker 1: we can see it. So the good news is that
• 18:15
  Speaker 1: the bigger it is, the easier it is to see.
• 18:18
  Speaker 1: And NASA has been tracking these things for a few
• 18:21
  Speaker 1: decades pretty carefully, and they're pretty sure that they've seen
• 18:24
  Speaker 1: all the really big ones, and then as you go
• 18:26
  Speaker 1: smaller and smaller on the scale, they get less and
• 18:28
  Speaker 1: less certain. But they have these goals to see, like
• 18:31
  Speaker 1: of all the objects greater than a kilometer, or of
• 18:35
  Speaker 1: all the objects greater than five kilometers. But as you said,
• 18:38
  Speaker 1: they're sometimes surprised, like when one of these things came
• 18:41
  Speaker 1: into the skies over Chelivinsk. This was a twenty meter
• 18:44
  Speaker 1: object that came really fast. It was small enough that
• 18:48
  Speaker 1: nobody knew it existed, and it created a huge explosion.
• 18:51
  Speaker 1: Two thousand people were hurt, buildings were shattered. So it's
• 18:55
  Speaker 1: definitely possible that there are ones out there that we
• 18:57
  Speaker 1: have not seen. The dash camp videos on that thing
• 19:00
  Speaker 1: are crazy. Do we know that that came from the
• 19:03
  Speaker 1: asteroid belt? Like, if something you know, makes its way
• 19:06
  Speaker 1: to Earth, can we back calculate where it started from? Yes,
• 19:09
  Speaker 1: Because of all the dash cam videos, we can calculate
• 19:12
  Speaker 1: the trajectory of this thing, and then we know its
• 19:14
  Speaker 1: mass and its velocity and its angle, and so we
• 19:16
  Speaker 1: could figure out where it came from. And so that
• 19:18
  Speaker 1: definitely came from somewhere in the asteroid belt. And there's
• 19:21
  Speaker 1: a huge number of objects out there's just way too
• 19:24
  Speaker 1: many to track now at Cheliabinsk, like explosion is never
• 19:28
  Speaker 1: going to end the human race, right. It could kill
• 19:30
  Speaker 1: thousands of people, would be a terrible disaster, but it's
• 19:33
  Speaker 1: not like a planet killer. You know, it's not going
• 19:35
  Speaker 1: to tear the planet in half, or it's not going
• 19:37
  Speaker 1: to cause the kind of devastation that would like wipe
• 19:39
  Speaker 1: out humanity. But still, you know, you definitely don't want
• 19:42
  Speaker 1: to lose two thousand people because you didn't notice something,
• 19:45
  Speaker 1: So you want your planetary defense shield to be pretty robust.
• 19:49
  Speaker 1: The interesting thing about the asteroids is that there's a
• 19:51
  Speaker 1: huge variety of these sizes. Like the asteroid belt itself,
• 19:54
  Speaker 1: half of the mass is in just four objects. Like
• 19:58
  Speaker 1: one of the things in the asteroid belt is a
• 20:00
  Speaker 1: dwarf planet called Series. I've heard of Series. Are there
• 20:04
  Speaker 1: other dwarf planets in the asteroid belt or is that
• 20:06
  Speaker 1: the only one? There are four objects that have like
• 20:08
  Speaker 1: half the mass. Series is the biggest one. It's like
• 20:10
  Speaker 1: almost a kilometer wide, and then it drops down pretty
• 20:13
  Speaker 1: quickly after that. But even if you add up all
• 20:16
  Speaker 1: of the mass of all of the stuff in the
• 20:18
  Speaker 1: asteroid belt. It's not that much. It's only like four
• 20:21
  Speaker 1: percent of the mass of the Moon. Still, though, you
• 20:24
  Speaker 1: don't want to get hit by an object that's like
• 20:26
  Speaker 1: four percent the mass of the Moon, Yeah, that would be.
• 20:30
  Speaker 1: And so how like do those things tend to stay
• 20:32
  Speaker 1: put or are they getting like kicked out pretty often?
• 20:35
  Speaker 1: It's a great question because you might wonder, like, why
• 20:38
  Speaker 1: are these things there? Why don't they just pull together
• 20:41
  Speaker 1: into like a new planet, right, And so you have
• 20:43
  Speaker 1: to understand all the forces on these things. So number
• 20:45
  Speaker 1: one of the reason that they haven't just formed their
• 20:48
  Speaker 1: own planet, you know, and declared independence from the Solar
• 20:51
  Speaker 1: System or whatever, is that these things are being tortured
• 20:54
  Speaker 1: by Jupiter. Right. Jupiter is such a massive planet. It's
• 20:58
  Speaker 1: so much bigger than everything else that it's gravity really
• 21:02
  Speaker 1: controls that sort of middle Solar System region, and there
• 21:05
  Speaker 1: are tidal forces on these things, you know, anything that
• 21:08
  Speaker 1: gets big enough near Jupiter. Jupiter's gravity pulls on the
• 21:12
  Speaker 1: closer part of it harder than it pulls on the
• 21:14
  Speaker 1: further part of it, which basically pulls it apart. And
• 21:17
  Speaker 1: so jupiters forces are constantly disrupting what would otherwise be
• 21:21
  Speaker 1: a nice steady formation of a new planet in the
• 21:24
  Speaker 1: asteroid belt. So these things have been whizzing around for
• 21:26
  Speaker 1: hundreds of millions of years, maybe billions of years. Sometimes
• 21:30
  Speaker 1: they do bounce into each other and then you know,
• 21:32
  Speaker 1: they careen off into the inner Solar System. They can
• 21:34
  Speaker 1: also just fly around in a nice stable orbit for
• 21:37
  Speaker 1: you know, billions of years and not bother anyone. And
• 21:39
  Speaker 1: you know, I feel like, now that you and I
• 21:41
  Speaker 1: have recorded a nice number of episodes together, I feel
• 21:44
  Speaker 1: like the answer now just about any astronomy question of
• 21:48
  Speaker 1: why is it like that, the answer is Jupiter. Why
• 21:52
  Speaker 1: is this weird thing happening? Probably Jupiter that's the go
• 21:55
  Speaker 1: to answer. Jupiter is such a bully in the Solar
• 21:57
  Speaker 1: System because of its gravity affects every right. There may
• 22:01
  Speaker 1: have been like another planet like Nepportunity Urinus, that was
• 22:04
  Speaker 1: tossed out of the Solar System by Jupiter. It's crazy,
• 22:08
  Speaker 1: and we had that a whole fun episode about how
• 22:09
  Speaker 1: Jupiter might have been formed in the outer Solar System,
• 22:12
  Speaker 1: migrated in, came back out because it was saved by Saturn. Like,
• 22:16
  Speaker 1: the story of our Solar system is really incredible and dynamic.
• 22:20
  Speaker 1: It's not just like a bunch of rocks, calmly floating
• 22:22
  Speaker 1: in space the same way forever. You know, this chaos,
• 22:25
  Speaker 1: there's intrigue, there's backstabbing, there is it's totally wild, and
• 22:31
  Speaker 1: especially in the very early part of the history of
• 22:33
  Speaker 1: the Solar System. We think that the asteroid belt used
• 22:35
  Speaker 1: to have a lot more mass to it, but something
• 22:38
  Speaker 1: like nine percent of it was lost in the first
• 22:41
  Speaker 1: hundred million years because things banged into each other and
• 22:44
  Speaker 1: then fell into the Sun or got ejected from the
• 22:46
  Speaker 1: Solar System. So the asteroid belt we have today is
• 22:49
  Speaker 1: like a shadow of the very early asteroid belt we
• 22:52
  Speaker 1: had in the history of the Solar System, which is
• 22:54
  Speaker 1: probably lucky for us. I don't think we would have
• 22:56
  Speaker 1: wanted to have been around when all the chaotic stuff
• 22:58
  Speaker 1: was flying around, and that's the heavy bombardment period of
• 23:01
  Speaker 1: the Solar System, and we think that Earth, before its
• 23:04
  Speaker 1: current atmosphere was formed, was just like rained down by
• 23:07
  Speaker 1: these death rocks. Yeah, I'm glad I missed the death
• 23:09
  Speaker 1: rock period. It would have been hard to convince your
• 23:12
  Speaker 1: children it wasn't happening if you lived back then. Yeah, yeah,
• 23:15
  Speaker 1: you know, it's nice to be able to lie to
• 23:17
  Speaker 1: your kids and You're right, that would have that would
• 23:18
  Speaker 1: have made it harder and maybe not lie, you know,
• 23:20
  Speaker 1: sugarcoat the truth. You go preserve their childhood innocence. Something
• 23:25
  Speaker 1: else that surprised me about the asteroid available and reading
• 23:27
  Speaker 1: about it is that it's not just a collection of
• 23:29
  Speaker 1: rocks between Mars and Jupiter. There's two clumps of rocks
• 23:33
  Speaker 1: that are co orbiting with Jupiter. They're like in Jupiter's orbit,
• 23:37
  Speaker 1: but one of them is trailing and one of them
• 23:39
  Speaker 1: is leading Jupiter. How and how much stuff is in that?
• 23:42
  Speaker 1: Not that much, but because there are astronomers involved, they
• 23:45
  Speaker 1: have silly names. So one group called the Greeks and
• 23:48
  Speaker 1: the other one is called the Trojans, And I guess that's,
• 23:50
  Speaker 1: you know, a play on the fact that we name
• 23:52
  Speaker 1: all of our Solar System planets after Greek gods. So okay,
• 23:56
  Speaker 1: So I'm working on this book about space settlements, and
• 23:58
  Speaker 1: so whenever I read about the as Red Belt, I
• 24:00
  Speaker 1: am reading about people who are interested in mining the
• 24:03
  Speaker 1: asteroids because there's cool stuff in those asteroids. Can you
• 24:06
  Speaker 1: tell us a little bit about what's in those asteroids
• 24:08
  Speaker 1: and like how common the good stuff is? Yeah, the
• 24:11
  Speaker 1: asteroid belt is made from the same stuff as the
• 24:14
  Speaker 1: rest of the Solar System. It means that there's a
• 24:16
  Speaker 1: lot of carbon, there's a lot of silicon. There's also
• 24:19
  Speaker 1: a lot of metal and so as I'm sure you know,
• 24:21
  Speaker 1: some of those asteroids have like huge nodes of platinum
• 24:24
  Speaker 1: or other rare earth metals that could be pretty useful
• 24:27
  Speaker 1: for a space based industry. Do you find any of
• 24:30
  Speaker 1: those schemes for mining asteroids to be plausible at all?
• 24:35
  Speaker 1: That's gonna be a short chapter in your next book,
• 24:37
  Speaker 1: right space mining? Will it work? No? Maybe eventually, and
• 24:42
  Speaker 1: it will support some settlements, but I'm not seeing a
• 24:44
  Speaker 1: near term potential. But check out my book for more information.
• 24:48
  Speaker 1: It's only a few pages long. We find a way
• 24:52
  Speaker 1: to draw it out, that's what authors do you know?
• 24:55
  Speaker 1: I see it's just like no, like five pages of nos.
• 25:01
  Speaker 1: I don't think my editor would let that slide. There
• 25:04
  Speaker 1: are a narrow you know, maybe taking water from the
• 25:07
  Speaker 1: asteroids and selling it to the I S S or
• 25:09
  Speaker 1: two moon settlements. That might be a like, you know,
• 25:12
  Speaker 1: in a couple of decades feasible, But in the very
• 25:16
  Speaker 1: near term, I don't think it's going to work out economically,
• 25:19
  Speaker 1: So very naively, why not if I'm up in space
• 25:22
  Speaker 1: and I need to build something, why shouldn't I just
• 25:24
  Speaker 1: go get iron from some near my asteroid instead of
• 25:27
  Speaker 1: like lifting it off the surface of the Earth. Well,
• 25:29
  Speaker 1: so the problem is for starters, you said, if I'm
• 25:32
  Speaker 1: up in space trying to build something, which hasn't happened yet,
• 25:35
  Speaker 1: and so like, I mean, we've gone up to space
• 25:39
  Speaker 1: to assemble things that are pre exists that we built
• 25:41
  Speaker 1: on Earth. You know, like we've assembled the I S S.
• 25:44
  Speaker 1: And there have been some groups like Made in Space
• 25:46
  Speaker 1: that three do some three D printing and stuff in space.
• 25:49
  Speaker 1: But like it's gonna take a while before we can
• 25:51
  Speaker 1: really get these settlements started. There's a lot we don't
• 25:53
  Speaker 1: know about how the human body responds to microgravity or
• 25:56
  Speaker 1: to the spit or radiation in space. And then there's
• 25:59
  Speaker 1: a lot we don't know about how to actually get
• 26:01
  Speaker 1: these asteroids. So you know a lot of them are
• 26:03
  Speaker 1: rubble piles. They're not just like this big dense thing.
• 26:06
  Speaker 1: How do you collect a rubble pile where if you
• 26:08
  Speaker 1: try to land on it, you're just going to sort
• 26:09
  Speaker 1: of smooth it out and push it away, And then
• 26:12
  Speaker 1: how do you extract or in space? Or are you
• 26:15
  Speaker 1: just going to bring the asteroid and drop it to Earth.
• 26:17
  Speaker 1: Probably not a great idea. There's just a lot of
• 26:20
  Speaker 1: problems that need to get solved before this becomes something
• 26:22
  Speaker 1: that we need and something that we actually can do. Wow.
• 26:25
  Speaker 1: Way to bring the harsh reality down to my dreams there, Kelly. Well,
• 26:29
  Speaker 1: you know, I guess we're taking turn. I was expecting
• 26:34
  Speaker 1: to get a little bit of that, you know, childhood
• 26:36
  Speaker 1: innocence protection you offer your kids. But I guess that's,
• 26:38
  Speaker 1: you know, an umbrella only for your family. You're a
• 26:40
  Speaker 1: grown adult, Daniel. I can deal with it. I can
• 26:43
  Speaker 1: deal with it. Okay, Well, now that I've had an
• 26:47
  Speaker 1: opportunity to crush your dreams, let's take an uplifting break,
• 26:50
  Speaker 1: and when we come back, we'll talk about some of
• 26:52
  Speaker 1: the risks that are farther out in the Solar system. Okay.
• 27:08
  Speaker 1: I hope you didn't have too many existential crises during
• 27:11
  Speaker 1: the break. But we're back, and now let's talk about
• 27:14
  Speaker 1: the Kuiper belts, and we talked about the asteroid belts.
• 27:17
  Speaker 1: Risks are looking for us in the Kiper Belt. So
• 27:19
  Speaker 1: fortunately I survived that break. No large objects from space
• 27:22
  Speaker 1: crash landed on my house. So I'm still here to
• 27:25
  Speaker 1: talk about future dangers. And some of the most dangerous
• 27:28
  Speaker 1: objects in the Solar System are not in the asteroid belt.
• 27:31
  Speaker 1: They come from further out. So the Kuiper Belt is
• 27:33
  Speaker 1: a source of short period comets ice balls that orbit
• 27:37
  Speaker 1: the Sun with a period about less than two hundred
• 27:40
  Speaker 1: years or so. And these are basically little things that
• 27:43
  Speaker 1: never formed a planet. But they're much further out there,
• 27:45
  Speaker 1: like past Neptune there between thirty and fifty AU. Remember
• 27:50
  Speaker 1: AU as the distance between the Sun and the Earth.
• 27:53
  Speaker 1: So it's sort of like a second asteroid belt, but
• 27:55
  Speaker 1: it's further out and more dangerous. You you're suggesting these
• 27:59
  Speaker 1: things are more danger is because they come from further out,
• 28:02
  Speaker 1: which makes them harder to spot. Right. Things that are
• 28:04
  Speaker 1: further away are harder to see, so we can't track
• 28:07
  Speaker 1: them as well. And because they come from further out
• 28:10
  Speaker 1: there going faster when they do come into the inner
• 28:12
  Speaker 1: Solar System. Imagine like rolling a rock down a hill,
• 28:15
  Speaker 1: it's gonna go pretty fast. Instead roll that rock from
• 28:18
  Speaker 1: like the top of a mountain. Then by the time
• 28:20
  Speaker 1: it gets to the bottom, it's gonna be going super
• 28:22
  Speaker 1: duper fast. So the Earth moves around the Sun like
• 28:25
  Speaker 1: thirty kilometers per second, and asteroids typical velocities like forty
• 28:29
  Speaker 1: kilometers per second. But comets can be going much much faster,
• 28:32
  Speaker 1: seventy to a hundred kilometers per second, and that translates
• 28:36
  Speaker 1: into kinetic energy, which means more destruction if they do hit.
• 28:40
  Speaker 1: So I heard you use asteroiding comets. So we've got
• 28:43
  Speaker 1: the asteroid belt which has a lot of asteroids, and
• 28:46
  Speaker 1: so does the Kiper Belt have more comets then? Yeah,
• 28:49
  Speaker 1: it's just a name thing. If it comes from the
• 28:51
  Speaker 1: asteroid belt, we call it an asteroid. If it comes
• 28:53
  Speaker 1: from the Kuiper Belt, we call it a commet. There's
• 28:55
  Speaker 1: also a difference in the makeup because as the Solar
• 28:58
  Speaker 1: system formed, the amount of UF in various parts of
• 29:01
  Speaker 1: the Solar System was different, and so for example, in
• 29:03
  Speaker 1: the inner Solar System you don't have as much ice
• 29:06
  Speaker 1: and water a lot of that was vaporized, whereas in
• 29:09
  Speaker 1: the outer Solar System, before the Sun could vaporize, it
• 29:12
  Speaker 1: is frozen into crystals and it could participate in like accretions,
• 29:16
  Speaker 1: So things that like started to gather together and gravitationally.
• 29:19
  Speaker 1: Who are also able to gather ice as part of
• 29:21
  Speaker 1: their makeup, which is why the ice giants Neptune and
• 29:24
  Speaker 1: urine Is are out there in the outer Solar System.
• 29:27
  Speaker 1: You don't get ice giants between Venus and Mercury, for example.
• 29:31
  Speaker 1: So the things in the Kuiper Belts are more like
• 29:33
  Speaker 1: snowballs and the things in the Asteroid Belt are more
• 29:36
  Speaker 1: like rocks. Interesting, okay, And then we talked about series
• 29:40
  Speaker 1: the dwarf planet in the asteroid belt, and I know,
• 29:43
  Speaker 1: poor Pluto is now merely a dwarf planet. Are there
• 29:47
  Speaker 1: other dwarf planets and the Kuiper Belts because we have
• 29:50
  Speaker 1: now exhausted my knowledge of dwarf planets. There are lots
• 29:55
  Speaker 1: of dwarf planets. And that other thing is the whole controversy,
• 29:58
  Speaker 1: people realizing, oh, Pluto's not that special. Yes, we love Pluto,
• 30:02
  Speaker 1: it has a heart on it, all that stuff, but
• 30:05
  Speaker 1: it's just one of lots of these objects deep into
• 30:08
  Speaker 1: Solar System where things didn't form into larger masses. And
• 30:13
  Speaker 1: so I think if we made Pluto a planet, than
• 30:15
  Speaker 1: any time we found another object that size, and we're
• 30:18
  Speaker 1: going to find a lot, that would be adding another
• 30:20
  Speaker 1: planet to the Solar System. And that's I think the
• 30:23
  Speaker 1: argument for drawing the line before Pluto. But the point is,
• 30:26
  Speaker 1: as you say, there's a lot of stuff out there,
• 30:28
  Speaker 1: and you might wonder again, like, well, why doesn't this
• 30:31
  Speaker 1: form into big planets? Like there's no Jupiter out there
• 30:34
  Speaker 1: in the deep Solar system to prevent these guys from forming.
• 30:37
  Speaker 1: The answer is just mostly time and space. As you
• 30:40
  Speaker 1: get further out from the Sun, the density of stuff
• 30:42
  Speaker 1: drops and the space between it grows because you're just
• 30:45
  Speaker 1: getting more and more space as radius cubed, and so
• 30:48
  Speaker 1: it takes longer for stuff to come together. Gravity is
• 30:51
  Speaker 1: pretty weak, and so this stuff just takes a long
• 30:54
  Speaker 1: time to come together. Wasn't deep impact about something coming
• 30:57
  Speaker 1: from the Piper Belt. So this deep impact the moving
• 30:59
  Speaker 1: from Hollywood, which I think was in response to seeing
• 31:02
  Speaker 1: Shoemaker Levy impact Jupiter, and then Hollywood responded by making
• 31:06
  Speaker 1: an actual mission to a comet and calling it deep Impact,
• 31:10
  Speaker 1: so you know, having the whole like Hollywood science cycle there.
• 31:14
  Speaker 1: So this is their super cool mission because it went
• 31:16
  Speaker 1: out and visited a comet and basically punched it in
• 31:19
  Speaker 1: the face to see, like what's going on? And I'm
• 31:26
  Speaker 1: just glad they weren't like aliens hiding inside that comet,
• 31:29
  Speaker 1: you know, observing us and being like WHOA. I imagine
• 31:31
  Speaker 1: like aliens on a steak out, you know, eating pistachio nuts,
• 31:34
  Speaker 1: and then all of a sudden Nasa comes out and
• 31:36
  Speaker 1: punches them in the face. What the heck man? Totally unnecessary?
• 31:41
  Speaker 1: I know you could have just said high. Anyway, as
• 31:44
  Speaker 1: far as we know, there weren't any aliens hiding inside
• 31:46
  Speaker 1: the comet temple one. And when they punched it, they
• 31:49
  Speaker 1: learned a lot about what these things are made out of.
• 31:51
  Speaker 1: Turns out, these things, or at least this one, was
• 31:54
  Speaker 1: a lot more dusty and less icy than they expected.
• 31:57
  Speaker 1: Like the stuff that's on it is not as much
• 32:00
  Speaker 1: ice and sand, more like baby powder. It's like this
• 32:04
  Speaker 1: really really fine dust that this thing is made out of.
• 32:08
  Speaker 1: And so does that make it less dangerous for us?
• 32:12
  Speaker 1: What is the implication for me of what you just said, Daniel,
• 32:15
  Speaker 1: That's what I'm wondering. It's a good question. It doesn't
• 32:18
  Speaker 1: matter that much if it's made out of baby powder
• 32:20
  Speaker 1: or sand. What matters is like how much it's holding together,
• 32:23
  Speaker 1: because when it hits the atmosphere, if it breaks up
• 32:25
  Speaker 1: into thousands and thousands of small pieces, then that kinetic
• 32:29
  Speaker 1: energy is spread over a larger area, so you're less
• 32:31
  Speaker 1: likely to have like one big one that's going to
• 32:33
  Speaker 1: land in the Pacific Ocean and cause a mile high tsunami.
• 32:37
  Speaker 1: Better if it's like a rubble pile that gets spread
• 32:39
  Speaker 1: out by some impact or or something else. Doesn't really
• 32:42
  Speaker 1: matter that much if it's baby powder or sand. But
• 32:45
  Speaker 1: so that sounds like the exact opposite of what the
• 32:47
  Speaker 1: people who called inset. Yeah, people who are worried about
• 32:50
  Speaker 1: getting these dangerous fragments, but it's actually much much better.
• 32:53
  Speaker 1: Like would you rather be shot by an armor piercing
• 32:55
  Speaker 1: bullet or a shotgun? You know, you have like lots
• 32:58
  Speaker 1: of very small pellets which will embed them cells in
• 33:00
  Speaker 1: your skin, but are less likely to go all the
• 33:02
  Speaker 1: way through and in the same way, the Earth can
• 33:05
  Speaker 1: absorb a pretty big hit. That's what shooting stars are, right.
• 33:08
  Speaker 1: We're constantly getting hit by lots and lots of small
• 33:11
  Speaker 1: rocks and they briefly heat up the atmosphere. Much better
• 33:14
  Speaker 1: to be hit by lots and lots of fragments than
• 33:17
  Speaker 1: it is to be hit by one big one. Okay,
• 33:19
  Speaker 1: that makes sense, all right, So we've got the asteroid
• 33:21
  Speaker 1: belt and the Kuiper Belt. That's all the like you know,
• 33:25
  Speaker 1: human killer locations in the Solar System, right. Unfortunately, No,
• 33:30
  Speaker 1: there's one more source of death out there in deep space,
• 33:34
  Speaker 1: and that's my favorite part of the Solar System. Actually,
• 33:37
  Speaker 1: it's the Ort Cloud. This is well beyond the Kuiper Belt.
• 33:40
  Speaker 1: It's another cloud of I see many planets and objects.
• 33:44
  Speaker 1: This is much much further out. In fact, that so
• 33:48
  Speaker 1: far from the Sun that you can almost think of
• 33:50
  Speaker 1: it as sort of like transitional out into deeper space.
• 33:54
  Speaker 1: This is like two thousand to like a hundred thousand
• 33:57
  Speaker 1: a U. So we're talking about like you know, one
• 34:00
  Speaker 1: or two light years from the Sun. There's actually two
• 34:03
  Speaker 1: layers of Orc cloud is like an inner Taurus and
• 34:06
  Speaker 1: then an outer sphere that the Sun is just like
• 34:09
  Speaker 1: barely holding onto. Thanks son for holding onto a human killer.
• 34:14
  Speaker 1: That sounds really far away. Is there a lot of
• 34:16
  Speaker 1: stuff out there that could get us? It's very far away.
• 34:18
  Speaker 1: It's like a thousand times further than the Kuiper Belt.
• 34:21
  Speaker 1: But they think that it's got like trillions of objects
• 34:24
  Speaker 1: in it, each of which are bigger than a kilometer,
• 34:27
  Speaker 1: and they're probably billions of things bigger than twenty kilometers. Remember,
• 34:31
  Speaker 1: anything bigger than like five kilometers is basically an extinction
• 34:35
  Speaker 1: event if it hits the Earth. So there's a huge
• 34:37
  Speaker 1: amount of stuff. If you add it all up, it's
• 34:40
  Speaker 1: like five times the mass of the Earth. So it's
• 34:43
  Speaker 1: much much more massive than the asteroid belt or the
• 34:46
  Speaker 1: Kuiper Belt. So I'm definitely not telling my daughter about
• 34:49
  Speaker 1: these existential risks, and I'm kind of feeling like you
• 34:51
  Speaker 1: shouldn't be telling me about these. The other scary thing
• 34:55
  Speaker 1: about them is that when they make comments because you know,
• 34:58
  Speaker 1: like a nearby star comes by and disturbs them and
• 35:00
  Speaker 1: one of them falls into the inner Solar System, those
• 35:03
  Speaker 1: comments are very very long period comments. It could be
• 35:06
  Speaker 1: like thousands of years. What that means is that we
• 35:09
  Speaker 1: might not have seen it before. Like some comments we
• 35:12
  Speaker 1: see every seventy seven years or every five years. We
• 35:14
  Speaker 1: know what we see it, we can track it, we
• 35:16
  Speaker 1: can predict where it's gonna go. There could be a
• 35:18
  Speaker 1: comment out there that goes around the Sun every nineteen
• 35:21
  Speaker 1: thousand years and we just haven't been doing astronomy that long,
• 35:24
  Speaker 1: so we've never seen it. And the first time we
• 35:26
  Speaker 1: see it might be when we discover, Oh my gosh,
• 35:29
  Speaker 1: this thing is on a collision course for Earth, and
• 35:31
  Speaker 1: how much lead time on something like that would we have.
• 35:34
  Speaker 1: It depends a lot on how good our telescopes are
• 35:36
  Speaker 1: and how lucky we get, because these things are pretty
• 35:40
  Speaker 1: dark and moving pretty fast, and so it might just
• 35:43
  Speaker 1: be months. If we're lucky, it would be years, but
• 35:46
  Speaker 1: it might just be months. All right, Well, on that
• 35:48
  Speaker 1: dark note, let's take another break, and when we come back,
• 35:51
  Speaker 1: we'll talk about the possible scale of devastation. All right.
• 36:08
  Speaker 1: I hope everybody had a nice break and we're beat
• 36:10
  Speaker 1: to talk about the scale of devastation. So okay, tell
• 36:13
  Speaker 1: us a bit about what we know about how awful
• 36:15
  Speaker 1: these things can be, all right, and I'll try to
• 36:18
  Speaker 1: match your upbeat tone when we're talking about planet wide catastrophes. Yeah. Yeah, Well,
• 36:25
  Speaker 1: we don't know for sure. All we can do is
• 36:27
  Speaker 1: estimate based on what we've seen and the smaller ones,
• 36:30
  Speaker 1: you know, things less than a meter for example, we
• 36:32
  Speaker 1: see this all the time, like every day. Basically, things
• 36:36
  Speaker 1: that are less than a meter hit the top of
• 36:38
  Speaker 1: the atmosphere and make shooting stars. And Kelly tells her
• 36:41
  Speaker 1: kids nice fantasy stories about the universe. They are pretty
• 36:47
  Speaker 1: and then as you get bigger, like if something gets
• 36:49
  Speaker 1: to be about five meters wide, we think one of
• 36:52
  Speaker 1: these things hit the atmosphere about once every five years.
• 36:56
  Speaker 1: So already just five ms wide. You know, this is
• 37:00
  Speaker 1: of an apartment or something. It's getting pretty rare, just
• 37:02
  Speaker 1: every once in five years. The problem is that something
• 37:05
  Speaker 1: that big has a lot of mass, and so it
• 37:07
  Speaker 1: actually delivers an enormous amount of energy to the upper atmosphere,
• 37:11
  Speaker 1: but the damage is constrained to the upper atmosphere, because
• 37:14
  Speaker 1: I don't feel like every five years I'm hearing about
• 37:17
  Speaker 1: massive scary asteroid related events. It's mostly constrained to the
• 37:20
  Speaker 1: upper atmosphere, but it releases as much energy as an
• 37:23
  Speaker 1: atomic bomb. The unit here is like the power of
• 37:26
  Speaker 1: the bomb dropped on Hiroshima. So this is like one
• 37:29
  Speaker 1: Hiroshima every five years. Usually this explodes like somewhere over
• 37:33
  Speaker 1: the Pacific, and so it doesn't really matter. It doesn't
• 37:35
  Speaker 1: affect anybody, and it doesn't affect the satellites because they're
• 37:39
  Speaker 1: above where the atmosphere is, and so the big boom
• 37:43
  Speaker 1: is below them. Is that right? Yeah? And then as
• 37:45
  Speaker 1: you get bigger, so if you have one like twenty
• 37:47
  Speaker 1: mes y and that's about the size of the one
• 37:49
  Speaker 1: that hit Chill that comes about every fifty years, and
• 37:53
  Speaker 1: that's the power of like thirty Hiroshima's So when that
• 37:57
  Speaker 1: blew up over that city, it was an enormous explode,
• 38:00
  Speaker 1: like we're talking about equivalent to a nuclear attack. So far,
• 38:03
  Speaker 1: we've been super lucky that when these things have fallen,
• 38:06
  Speaker 1: they've fallen in relatively like uninhabited areas. So like Chilabinsk,
• 38:11
  Speaker 1: I'll never say it, right, but that was in Siberia, right,
• 38:13
  Speaker 1: and like in a low population area. Yeah, but you
• 38:16
  Speaker 1: know not the windows were shattered. Two thousand people were hurt.
• 38:19
  Speaker 1: There was an event in earlier part of this century,
• 38:21
  Speaker 1: Tunguska in eight which flattened hundreds of square miles of forest.
• 38:26
  Speaker 1: If you look at these pictures, has all these trees
• 38:28
  Speaker 1: just like lying straight down. It's incredible. That's also Siberia,
• 38:33
  Speaker 1: isn't it, Yes, exactly, Siberia is big, and so it's
• 38:36
  Speaker 1: going to take a lot of hits. All right, So
• 38:38
  Speaker 1: so how about let's let's go up a level. What
• 38:40
  Speaker 1: happens when you get up to the next level of devastation, Well,
• 38:43
  Speaker 1: if you go up to like a kilometer We think
• 38:45
  Speaker 1: these will impact the Earth about once every five hundred
• 38:48
  Speaker 1: thousand years, and it's good that they're that rare because
• 38:52
  Speaker 1: these things contain about as much energy as three million horosiumas.
• 38:57
  Speaker 1: Is that an extinction level event? That's crazy? It might be.
• 39:00
  Speaker 1: It's ride on the edge. If you go up to
• 39:02
  Speaker 1: like five thousand meters like five kilometer wide rock, it
• 39:05
  Speaker 1: should come about every twenty million years, and yeah, then
• 39:09
  Speaker 1: we're all toast. If it hits in the water, you're
• 39:11
  Speaker 1: getting like a mile high tsunami and an incredible amount
• 39:14
  Speaker 1: of vapor in the atmosphere, which is going to cause
• 39:16
  Speaker 1: a runaway greenhouse effect. If it hits on land, you're
• 39:19
  Speaker 1: gonna get super volcanoes, You're gonna get incredible amount of dust.
• 39:23
  Speaker 1: It's not going to be fun for anybody. Is one
• 39:25
  Speaker 1: of those scenarios better than the other? It was probably not.
• 39:30
  Speaker 1: Probably both. You're just dead and that's that. Are you
• 39:32
  Speaker 1: imagining some scenario where like you have to choose where
• 39:35
  Speaker 1: you're like, Kelly, where do you want this thing to hit?
• 39:38
  Speaker 1: The Earth is waiting for you? Well, you know, as
• 39:41
  Speaker 1: as a person who lives on a farm, you encounter
• 39:44
  Speaker 1: a lot of preppers and you find yourself talking about
• 39:47
  Speaker 1: scenarios where like could I survive this? Could I survive that?
• 39:51
  Speaker 1: Like under what you know parameter range? Do I have
• 39:54
  Speaker 1: a chance? And I think in general Zack and I
• 39:56
  Speaker 1: are probably just goners because we could never defend ourselves.
• 40:00
  Speaker 1: But you know, I do wonder these things sometimes, but
• 40:02
  Speaker 1: it sounds like probably one way or another we'd be gonners. Yeah,
• 40:05
  Speaker 1: if it's big enough, you be gone. If it's smaller,
• 40:07
  Speaker 1: you know, like a one kilometer rock, I think you
• 40:09
  Speaker 1: probably prefer it to land in fairly shallow water. Shallow
• 40:13
  Speaker 1: so you don't get like a mile high tsunami, but
• 40:15
  Speaker 1: some water so it absorbs a little bit of the
• 40:17
  Speaker 1: impact and doesn't just throw up as much dust into
• 40:20
  Speaker 1: the atmosphere. So if you have to pick, maybe you know,
• 40:23
  Speaker 1: send it to the Mediterranean. Got it? But I guess
• 40:24
  Speaker 1: you don't usually get to pick so for these extinction
• 40:27
  Speaker 1: level events. So you did mention that whether our ability
• 40:30
  Speaker 1: to know that they're coming depends on things like you know,
• 40:33
  Speaker 1: how how big they are and have what you know,
• 40:35
  Speaker 1: if they're dark or easy to see. When we're talking
• 40:37
  Speaker 1: about extinction level events, do we like definitely can we
• 40:40
  Speaker 1: definitely see those coming. Well, we have a heads up,
• 40:42
  Speaker 1: So there's good news and there's bad news. I'll give
• 40:45
  Speaker 1: you the good news first, and then you can shut
• 40:46
  Speaker 1: your ears for the bad news if you choose. The
• 40:48
  Speaker 1: good news is that we've been working pretty hard on this,
• 40:51
  Speaker 1: and NASA thinks they know where all the planet killers
• 40:55
  Speaker 1: are and that none of them are going to hit
• 40:57
  Speaker 1: the Earth in the next few hundred years. So that's
• 40:59
  Speaker 1: the good news. Because the bigger ones are easy to see.
• 41:03
  Speaker 1: They tend to reflect more light and so be visible
• 41:05
  Speaker 1: in our telescopes. The bad news is that the most
• 41:08
  Speaker 1: dangerous ones are the comets, and those are harder to
• 41:11
  Speaker 1: see because they come from further out. They're less predictable.
• 41:15
  Speaker 1: We might not see one at all before we discover
• 41:17
  Speaker 1: it's on a trajectory for the Earth. Like these asteroids,
• 41:20
  Speaker 1: we get to watch some wizz around the Sun for
• 41:22
  Speaker 1: years and carefully plot their trajectory, which allows us to
• 41:25
  Speaker 1: predict for hundreds of years in the future where they
• 41:28
  Speaker 1: might go. Common it might be the first time we
• 41:31
  Speaker 1: see it is when we discover it's headed towards the Earth.
• 41:34
  Speaker 1: Oh my gosh. Okay, so say we see it for
• 41:36
  Speaker 1: the first time, what are our options has NASA planned
• 41:40
  Speaker 1: for that too. You gotta walk back the existential dread
• 41:43
  Speaker 1: now NASA has planned for that. And I actually spoke
• 41:45
  Speaker 1: to Steve Chelsea at JPL, who is one of the
• 41:48
  Speaker 1: people in charge of this for the planet, and he said, quote,
• 41:52
  Speaker 1: if you're responsible for protecting the Earth from asteroids, there's
• 41:55
  Speaker 1: three things to keep track of, the first one is
• 41:58
  Speaker 1: to find them early. In other two don't really matter
• 42:01
  Speaker 1: very much. And you just told me it's hard to
• 42:06
  Speaker 1: find the most dangerous ones early. So I thought you
• 42:09
  Speaker 1: were supposed to be making me feel better and you've
• 42:12
  Speaker 1: done the opposite. I'm just glad that the Planetary Protection
• 42:16
  Speaker 1: Officer has a sense of humor about it. You know,
• 42:19
  Speaker 1: even if it's some dark humor. We'll all be chuckling
• 42:22
  Speaker 1: right before our demise. But it really does matter when
• 42:25
  Speaker 1: you see these things, because the earlier you see them,
• 42:28
  Speaker 1: the easier it is to protect the Earth. If you
• 42:31
  Speaker 1: can just like deflect this thing a tiny bit when
• 42:34
  Speaker 1: it's really still very far away, it'll just miss the Earth.
• 42:37
  Speaker 1: You know. Imagine somebody shooting a bullet at you, but
• 42:40
  Speaker 1: they're shooting it at you from like a thousand miles away,
• 42:43
  Speaker 1: very tiny breeze sideways will deflect the bullet and it'll
• 42:47
  Speaker 1: miss you, Whereas if somebody standing right in front of
• 42:49
  Speaker 1: you and attacking your point blank, that would be much
• 42:51
  Speaker 1: much harder to deflect that bullet. So if you see
• 42:54
  Speaker 1: something coming and it's still like a year or ten
• 42:57
  Speaker 1: years away, then the tiniest little push will send it
• 43:00
  Speaker 1: on another pass and it will miss the Earth. How
• 43:02
  Speaker 1: do you deflect an asteroid? How do you deflect an asteroid? Exactly? Well,
• 43:06
  Speaker 1: we got ideas and a lot of this is determined
• 43:09
  Speaker 1: by this formula that tells us how much deflection we need,
• 43:13
  Speaker 1: and it's about three and a half centimeters per second
• 43:17
  Speaker 1: of velocity divided by the number of years you got.
• 43:20
  Speaker 1: So that means if the thing is ten years away
• 43:22
  Speaker 1: from hitting, you only have to deflect it like three
• 43:25
  Speaker 1: and a half millimeters per second. That's a tiny change
• 43:28
  Speaker 1: in its velocity. But if it's one month away from hitting,
• 43:32
  Speaker 1: then you have to deflect it like thirty centimeters per second,
• 43:35
  Speaker 1: which is a lot more. We're talking about a big,
• 43:37
  Speaker 1: massive rock, and especially since Chi was a surprise, I'm
• 43:42
  Speaker 1: guessing that you often don't have years, or I guess
• 43:45
  Speaker 1: it just depends. We hope that we will have years,
• 43:48
  Speaker 1: but yes you might not. And even in the case
• 43:50
  Speaker 1: of the asteroid belt, like their projections that none of
• 43:52
  Speaker 1: the planet killers are likely to hit the Earth, that
• 43:54
  Speaker 1: assumes that there aren't you know, collisions or surprises. They're like,
• 43:58
  Speaker 1: these things can be very hard to pick far out
• 44:00
  Speaker 1: into the future. The sort of error band grows very
• 44:03
  Speaker 1: quickly because of nonlinearities. This one gets near to that
• 44:06
  Speaker 1: one and tugs them this other one, and then you know,
• 44:08
  Speaker 1: chaos reigns and all of a sudden, the trajectories have changed.
• 44:12
  Speaker 1: So something we've got to keep a constant eye on
• 44:14
  Speaker 1: to see if things have changed. But we might have
• 44:16
  Speaker 1: a lot of warning. You know, the dinosaurs had a
• 44:18
  Speaker 1: lot of warning. They actually reconstructed the likely path of
• 44:21
  Speaker 1: the impact or that wiped out the dinosaurs, And it
• 44:24
  Speaker 1: has this funny loop in it where it looks like
• 44:26
  Speaker 1: I made a near miss past the Earth the first
• 44:29
  Speaker 1: time around, went through this gravitational keyhole and went around
• 44:32
  Speaker 1: the Sun and came back and then slammed into the Earth.
• 44:35
  Speaker 1: And it was so close that they think if you
• 44:37
  Speaker 1: had looked up, you could have seen it from the
• 44:39
  Speaker 1: surface of the Earth. And they did nothing about it.
• 44:41
  Speaker 1: I don't understand. It's their fault. You know, they were
• 44:43
  Speaker 1: busy telling their children it's nothing to worry about, and
• 44:46
  Speaker 1: so you know they weren't prepared, you know, trying to
• 44:50
  Speaker 1: decide where to go with that. Do you want? It's
• 44:51
  Speaker 1: not fair to victim blame, But it is possible for
• 44:54
  Speaker 1: us to potentially deflect an asteroid if we have enough time.
• 44:58
  Speaker 1: So what what would that look like? So say we
• 45:00
  Speaker 1: decide we've got some time, we're going to try to
• 45:02
  Speaker 1: deflect this asteroid. What would we How would we do that?
• 45:06
  Speaker 1: So there's a few really fun ideas. One of them
• 45:08
  Speaker 1: is called gravity deflection, and this is sort of like
• 45:12
  Speaker 1: a gravity tractor. The idea is that gravity pulls on stuff,
• 45:16
  Speaker 1: and so if you could get something else near the asteroid,
• 45:20
  Speaker 1: it's gravity would tug on the asteroid. So just like
• 45:22
  Speaker 1: launch a heavy blob of metal, put it near the asteroid,
• 45:25
  Speaker 1: and it's gravity will tug it off course so that
• 45:28
  Speaker 1: it doesn't hit the Earth. But I mean, that's going
• 45:30
  Speaker 1: to have to be an incredibly heavy blob of metal, right,
• 45:34
  Speaker 1: Like how big are we talk? Could we? I mean,
• 45:36
  Speaker 1: I guess if you load how many times you could
• 45:38
  Speaker 1: you have to load? Starship to make that happen, well,
• 45:41
  Speaker 1: it's a trade off. It either has to be very
• 45:43
  Speaker 1: very heavy or you need a lot of time. It
• 45:46
  Speaker 1: doesn't have to be that big. If you get this
• 45:48
  Speaker 1: thing up there ten years before it hits the Earth,
• 45:50
  Speaker 1: you can have a several hundred ton object and it
• 45:53
  Speaker 1: could really change the path of this object. But that's
• 45:56
  Speaker 1: the key thing. This gravity tractor is a very very
• 45:59
  Speaker 1: gentle ish It's very expensive and we take a long
• 46:02
  Speaker 1: time to work, so you can need like years of
• 46:04
  Speaker 1: lead time. So we have gone out two asteroids and comments,
• 46:09
  Speaker 1: so we at least have the technology to like get
• 46:12
  Speaker 1: to these far off places in the Solar System, but
• 46:15
  Speaker 1: not very quickly is the problem. Like we can send
• 46:18
  Speaker 1: these things out there, but you know they like passed
• 46:20
  Speaker 1: by Venus and do a gravitational slingshot. We're not really
• 46:23
  Speaker 1: in a hurry. We want to get them out there
• 46:25
  Speaker 1: with like minimal cost. When you're in a hurry, it's
• 46:28
  Speaker 1: a very different problem, and you want to minimize the
• 46:30
  Speaker 1: time it takes for your system to get there, and
• 46:32
  Speaker 1: that's not something we're currently great at. That sounds to
• 46:35
  Speaker 1: me like a pretty clever method which hopefully we could
• 46:38
  Speaker 1: pull off you know, but like Armageddon showed me that
• 46:41
  Speaker 1: what you really want to do is blow stuff up.
• 46:43
  Speaker 1: So what what are what are our options for blowing
• 46:46
  Speaker 1: stuff up? Well, there are a few options there. One
• 46:49
  Speaker 1: is not to blow it up, but just like knock
• 46:51
  Speaker 1: into it, like shoot a big rocket of at it,
• 46:54
  Speaker 1: you know, ten kilometers per second and bang into it,
• 46:57
  Speaker 1: and that might be enough like moment them to change
• 47:00
  Speaker 1: its course. Again, it depends on how early it is
• 47:03
  Speaker 1: in its trajectory. If it's about to hit next week,
• 47:06
  Speaker 1: that's gonna have no useful effect. If you're talking about
• 47:09
  Speaker 1: something that's gonna hit in a few years, it could
• 47:11
  Speaker 1: really change the path of the rocket. Have we ever
• 47:13
  Speaker 1: tried this or tried something like it to sort of
• 47:16
  Speaker 1: get a handle on how it would work. Yeah, NASA
• 47:18
  Speaker 1: actually launched the double Asteroid Redirection test called DART, which
• 47:23
  Speaker 1: is a kinetic impact or spacecraft. They launched in November one,
• 47:28
  Speaker 1: and it's going to hit this thing called dimorphous undred
• 47:31
  Speaker 1: eighty meter wide minor planet Moon. It's going to hit
• 47:34
  Speaker 1: in October of twenty twenty two, when this thing is
• 47:37
  Speaker 1: pretty close to the Earth. So we can turn our
• 47:39
  Speaker 1: telescopes and watch and see what happens, and I'll give
• 47:42
  Speaker 1: us a sense for like, well, what happens when you
• 47:44
  Speaker 1: bang basically a big bullet into an asteroid? Oh, that's awesome.
• 47:49
  Speaker 1: And presumably they were careful enough to do this far
• 47:52
  Speaker 1: enough away that it's not going to cause any problems.
• 47:54
  Speaker 1: Presumably they know what they're doing. Well, I don't know.
• 47:57
  Speaker 1: That's a pretty big if scope sometimes a though, NASA
• 47:59
  Speaker 1: has got a good track record, So all right, we'll
• 48:01
  Speaker 1: go with it. Are there any more like sort of
• 48:03
  Speaker 1: futuristic methods? I guess fusion rockets? That's pretty futuristic, right,
• 48:08
  Speaker 1: How about how about more futuristic methods. One of my
• 48:11
  Speaker 1: favorite methods is the laser method. The idea being if
• 48:14
  Speaker 1: you could shine a really powerful laser at one side
• 48:18
  Speaker 1: of the rock, it would melt ice and sublimate gases
• 48:20
  Speaker 1: from that side of the rock, basically creating a rocket
• 48:23
  Speaker 1: to push it sideways. So build a huge, powerful laser
• 48:27
  Speaker 1: and just zap the rock. That's pretty cool. Can you
• 48:30
  Speaker 1: use zap the rock with something other than a laser,
• 48:32
  Speaker 1: because you probably need a pretty powerful laser to pull
• 48:35
  Speaker 1: that trick off, although I guess not. If you're the
• 48:37
  Speaker 1: fart the sooner you catch it. The more time you have,
• 48:39
  Speaker 1: less powerful the laser needs to be. I'm catching on,
• 48:42
  Speaker 1: you're catching on. But they have a plan to build
• 48:44
  Speaker 1: this system in space and it would rely on ten
• 48:48
  Speaker 1: kilometer wide solar panel system. So now we're doing solar
• 48:52
  Speaker 1: power in space, and the idea is that you can
• 48:55
  Speaker 1: then zap these asteroids and send them off course. Of course,
• 48:59
  Speaker 1: the other worries Now you're building a huge space laser,
• 49:02
  Speaker 1: and you know, some hackers take control of it and
• 49:05
  Speaker 1: write their name on the Washington Monument or something existential
• 49:08
  Speaker 1: threats about. But you don't have to build a laser.
• 49:12
  Speaker 1: You could also just take advantage of the fact that
• 49:14
  Speaker 1: the Sun is out there in space and shooting out
• 49:17
  Speaker 1: a huge amount of energy. Oh okay, and so it's
• 49:20
  Speaker 1: shooting out a bunch of energy, but you know, the
• 49:22
  Speaker 1: aspirin has been moving the comment or the comment has
• 49:24
  Speaker 1: been moving in this world where the Sun exists, and
• 49:26
  Speaker 1: so you'd have to focus the energy right to to
• 49:28
  Speaker 1: get it to move off track. Yeah, So imagine the
• 49:30
  Speaker 1: way you take a magnifying glass and you use it
• 49:33
  Speaker 1: to like fry a small object. You build a huge
• 49:36
  Speaker 1: lens in space and you focus the Sun's energy on
• 49:39
  Speaker 1: this thing, and that can change its course, not in
• 49:43
  Speaker 1: the sense that you're trying to blow it up again.
• 49:45
  Speaker 1: All you need to do is heat up a little
• 49:47
  Speaker 1: edge of it so it creates a small rocket to
• 49:50
  Speaker 1: push it sideways, and then it goes off course. And
• 49:53
  Speaker 1: that might sound a little bit impractical. You're gonna build
• 49:55
  Speaker 1: this huge space lens and pointed at this thing. One
• 49:58
  Speaker 1: of my favorite ideas involve wrapping half of the asteroid
• 50:02
  Speaker 1: in foil, because you're right that they've already taken into
• 50:05
  Speaker 1: account the fact that the Sun is pushing on this thing.
• 50:07
  Speaker 1: But if you change how much energy it absorbs, if
• 50:10
  Speaker 1: you change how much momentum kick the Sun's light gives
• 50:12
  Speaker 1: it by making it more reflective, you're basically turning this
• 50:15
  Speaker 1: thing into a solar sale and that can send it
• 50:18
  Speaker 1: off course. So just wrap it an aluminum foil. Okay,
• 50:21
  Speaker 1: So this is where asteroid mining is going to take off.
• 50:24
  Speaker 1: You know, they're finally going to be able to get
• 50:26
  Speaker 1: the money by saying we're going to save the world
• 50:28
  Speaker 1: by going to the asteroids to get the aluminum will
• 50:31
  Speaker 1: coat the asteroid that's coming to get us, and then
• 50:33
  Speaker 1: suddenly everybody's going to be totally on board with us,
• 50:35
  Speaker 1: and maybe that will save money because it would be
• 50:37
  Speaker 1: expensive to shift the aluminum up from Earth and if
• 50:40
  Speaker 1: you could get an asteroid's worth of it. Anyway, we've
• 50:42
  Speaker 1: solved the asteroid mining problems. What about nuclear weapons? Since
• 50:45
  Speaker 1: we're talking about existential threats, all right, I think that
• 50:47
  Speaker 1: you're desperate to blow this thing up, all right. So
• 50:49
  Speaker 1: there's two categories. There's deflected and then there's destroyed. And
• 50:53
  Speaker 1: deflected is better if you can do it early because
• 50:55
  Speaker 1: it requires less explosive and less energy and cheaper in general.
• 50:59
  Speaker 1: But you're right, if it gets close enough, then you
• 51:01
  Speaker 1: got to just blow it up. And so people have
• 51:02
  Speaker 1: done actually a bunch of studies of like what's the
• 51:05
  Speaker 1: best strategy. Do you actually want to drill in deep
• 51:08
  Speaker 1: and blow up a nuclear weapon or do you want
• 51:10
  Speaker 1: to blow up the nuclear weapons sort of near it?
• 51:12
  Speaker 1: Because if the thing is like a rubble pile, as
• 51:14
  Speaker 1: you were saying before, blowing up a nuclear weapon in
• 51:16
  Speaker 1: the middle of it might not change its profile that much. Instead,
• 51:20
  Speaker 1: you might want to like blow it up on the
• 51:21
  Speaker 1: outside so it tends to disperse it more so you
• 51:24
  Speaker 1: get more of a shotgun effect on the Earth's atmosphere
• 51:27
  Speaker 1: instead of an impact or so. There are people whose
• 51:30
  Speaker 1: job it is, presumably to model nuclear explosions on asteroids
• 51:34
  Speaker 1: and like how that's going to impact the direction of
• 51:38
  Speaker 1: the like resulting rubble, And I, you know, if I
• 51:42
  Speaker 1: had life to live over again, that sounds like a
• 51:43
  Speaker 1: really fun job. Remember that everything we learned in science
• 51:48
  Speaker 1: is the product of somebody being so curious about it
• 51:51
  Speaker 1: that they decided to spend their life asking that particular
• 51:55
  Speaker 1: question and finding the answer. I was reading a thesis
• 51:58
  Speaker 1: last week from JOHNS. Hopkins and the chanical engineer who
• 52:01
  Speaker 1: spent his thesis studying how to blow up these asteroids
• 52:04
  Speaker 1: and doing hyper realistic simulations of what would happen when
• 52:08
  Speaker 1: you injected a nuclear weapon, how far down they would
• 52:10
  Speaker 1: have to go, and he actually found some surprises. He
• 52:13
  Speaker 1: thinks that the asteroids are probably stronger and tougher than
• 52:17
  Speaker 1: we have thought, and they would require more energy to
• 52:19
  Speaker 1: be shattered. And he was modeling like how the cracks
• 52:22
  Speaker 1: would move along the surface and whether they would make
• 52:24
  Speaker 1: it all the way to the other side, and the
• 52:26
  Speaker 1: effects of gravity of like pulling this thing back together
• 52:29
  Speaker 1: at the same time. It's a really complicated process and
• 52:32
  Speaker 1: I'll note that all sounds bad for asteroid mining as well.
• 52:35
  Speaker 1: There's another thing you can do if the thing is
• 52:37
  Speaker 1: gonna hit and you want to blow it up without
• 52:39
  Speaker 1: using the nuclear weapons. This actually reminds me about something
• 52:42
  Speaker 1: you brought up the other day about one time we
• 52:44
  Speaker 1: put a bunch of copper rods into space. Some folks
• 52:48
  Speaker 1: have this idea of laying out a series of rods
• 52:51
  Speaker 1: in space in front of the path of the asteroid.
• 52:55
  Speaker 1: And the idea is the asteroids already moving really really fast.
• 52:58
  Speaker 1: You don't need to shoot it with something else moving fast.
• 53:01
  Speaker 1: You just basically put a bunch of bullets in space
• 53:04
  Speaker 1: in front of it. And from the asteroids point of view,
• 53:06
  Speaker 1: it's like those bullets are coming at the asteroid. So
• 53:09
  Speaker 1: if you sort of create this spray of rods in
• 53:13
  Speaker 1: space between us and the asteroid, when it passes through,
• 53:16
  Speaker 1: it might get shredded and I will break it up,
• 53:18
  Speaker 1: and then you end up with again a lot of
• 53:20
  Speaker 1: small bits instead of one big one. Well, I'm personally
• 53:23
  Speaker 1: hoping that this question does not come up in my lifetime.
• 53:27
  Speaker 1: Do we have the option and I think I know
• 53:29
  Speaker 1: the answer to this one. Do we have the option
• 53:30
  Speaker 1: of abandoning ship if something is definitely going to destroy
• 53:33
  Speaker 1: Earth and we can't make it go away. Because at
• 53:35
  Speaker 1: the beginning of don't look up, some of them are
• 53:37
  Speaker 1: able to abandon ship. Well, I think Elon Musk probably
• 53:40
  Speaker 1: has those plans, but for the rest of us, we
• 53:42
  Speaker 1: don't really you know, there's no realistic way to get
• 53:45
  Speaker 1: six billion people off the Earth in a short amount
• 53:48
  Speaker 1: of time and let them live in space or colonize
• 53:51
  Speaker 1: Mars like. We are decades or hundreds of years away
• 53:54
  Speaker 1: from being able to do that. So unfortunately, there really
• 53:57
  Speaker 1: isn't an option of abandoning ship. People would like us
• 53:59
  Speaker 1: to have colonies on Mars so that humanity survives if
• 54:03
  Speaker 1: something does impact the Earth, and you know, I see
• 54:05
  Speaker 1: the logic in that argument, but it also means that
• 54:08
  Speaker 1: everybody else who's on Earth is going to die in
• 54:10
  Speaker 1: that scenario, so I think there's kind of a big
• 54:13
  Speaker 1: hole in that plan. I also think we're decades or
• 54:15
  Speaker 1: hundreds of years away from the Martians not dying when
• 54:18
  Speaker 1: the Earthlings die, because Martians are going to require resupply
• 54:22
  Speaker 1: trips from Earth for a long time before their self
• 54:25
  Speaker 1: sustaining and autarctic, So I think they're gonners too. They'll
• 54:29
  Speaker 1: just watch as Earthlings die and then they will slowly
• 54:32
  Speaker 1: fade away. So I think that everybody is a If
• 54:36
  Speaker 1: you will, I totally agree with you. And so what
• 54:38
  Speaker 1: we really need to do is it invest a little
• 54:40
  Speaker 1: bit more in telescopes. You'd be surprised at the tiny
• 54:43
  Speaker 1: amount of resources devoted to this. There's like a telescope
• 54:46
  Speaker 1: in New Mexico and one near Tucson, and a couple
• 54:49
  Speaker 1: of very small satellites. But you know, with more satellites
• 54:53
  Speaker 1: and more telescopes, so we could see more of these things,
• 54:55
  Speaker 1: and then we would have more time to respond if
• 54:57
  Speaker 1: we did see one of these guys headed for Earth.
• 54:59
  Speaker 1: So why do you think we aren't investing more in this?
• 55:02
  Speaker 1: Like it's it's clearly scary stuff. People can see shooting stars,
• 55:06
  Speaker 1: so they can like it shouldn't be hard to convince
• 55:09
  Speaker 1: them that there's stuff that's bombarding our atmosphere and as
• 55:11
  Speaker 1: it gets bigger, it can cause a problem. Why don't
• 55:13
  Speaker 1: we invest in this? I think it's for the same
• 55:15
  Speaker 1: reason that people let stuff fall apart on their house.
• 55:17
  Speaker 1: As a civilization, we're moving from crisis to crisis, and
• 55:21
  Speaker 1: if it's not the most important crisis in front of
• 55:23
  Speaker 1: you right now. Then it doesn't get attention, and so
• 55:26
  Speaker 1: it's sort of theoretical and maybe it's gonna happen, but
• 55:29
  Speaker 1: we don't need to deal with it today. Fine, let's
• 55:31
  Speaker 1: deal with it tomorrow. And so far tomorrow has income.
• 55:33
  Speaker 1: There have certainly been lots of crises in the last
• 55:36
  Speaker 1: couple of years to deal with. Yeah, we got plenty
• 55:38
  Speaker 1: on our plate, exactly. All right, Well, here's hoping we
• 55:41
  Speaker 1: all decide to invest in science. Though. I'm sure that
• 55:44
  Speaker 1: the money that we spend on those telescopes to protect
• 55:46
  Speaker 1: ourselves would probably also teach us a lot about the
• 55:48
  Speaker 1: world that we live in, So it would be a
• 55:50
  Speaker 1: good investment in lots of ways. Yea science, yea science.
• 55:54
  Speaker 1: And for those of you making long term plan we
• 55:56
  Speaker 1: do know that a rock called a popus, which is
• 55:59
  Speaker 1: three seventy wide, is due to make a very close
• 56:02
  Speaker 1: pass by the Earth on Friday the thirteenth in April nine.
• 56:07
  Speaker 1: So playing your camping trips, maybe by then Ada will
• 56:10
  Speaker 1: be old enough for me to explain what's happening to her.
• 56:13
  Speaker 1: We can, we can check it out. As you've seen
• 56:16
  Speaker 1: your happy birthday in the underground bunker, you have built.
• 56:19
  Speaker 1: That's right, that's not quite her birthday, but yeah, yeah,
• 56:22
  Speaker 1: maybe I'm not sure. We'll try try to tie that
• 56:24
  Speaker 1: to celebrating a birthday party. We'll see, all right. Well,
• 56:27
  Speaker 1: thanks everybody for coming along on this ride of curiosity
• 56:30
  Speaker 1: as we learn about the dangers that are out there
• 56:33
  Speaker 1: in space and what science has done and can do
• 56:36
  Speaker 1: to potentially protect us. Thanks very much, Kelly for joining us,
• 56:40
  Speaker 1: Thanks for having me, Thanks for listening. Everyone, all right,
• 56:42
  Speaker 1: tune in next time. Thanks for listening, and remember that
• 56:53
  Speaker 1: Daniel and Jorge Explain the Universe is a production of
• 56:56
  Speaker 1: my Heart Radio. For more podcast from my heart Radio,
• 56:59
  Speaker 1: visit i Heart Radio app, Apple Podcasts, or wherever you
• 57:03
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