Latest / Daniel and Kelly’s Extraordinary Universe / Where did the Earth's atmosphere come from?

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Where did the Earth's atmosphere come from? · Daniel and Kelly’s Extraordinary Universe

• 0:08
  Speaker 1: Hey, Daniel, did you see that amazing volcano that erupted
• 0:11
  Speaker 1: in Iceland? Is that the one in oh Nice? Is
• 0:15
  Speaker 1: that how you say it in Icelandic? I don't actually
• 0:17
  Speaker 1: speak Icelandic, though I do speak some Danish. Icelandic is
• 0:21
  Speaker 1: more like old Norse. But Iceland, the country is super
• 0:24
  Speaker 1: awesome and filled with volcanoes. Yeah, and there's one right now.
• 0:27
  Speaker 1: It's spewing hot lava like as we speak. Yeah, it's
• 0:31
  Speaker 1: like the Earth is breathing out more like burping or vomiting.
• 0:34
  Speaker 1: The Earth got indigestion, I think I wonder how you
• 0:37
  Speaker 1: say indigestion in Icelandic. It's just a volcano. I am
• 0:57
  Speaker 1: more handmade cartoonists and the creator of PhD comics. Hi,
• 1:01
  Speaker 1: I'm Daniel. I'm a particle physicist, and I'm substantially less
• 1:04
  Speaker 1: gassy than the island of Iceland. Are you less gassy
• 1:08
  Speaker 1: than the average physicists? No comment? Are you all full
• 1:12
  Speaker 1: of I'm more full of hot area exactly. But welcome
• 1:16
  Speaker 1: to our podcast. Daniel and Jorge Explained the Universe, a
• 1:18
  Speaker 1: production of I Heart Radio in which we blow your
• 1:21
  Speaker 1: mind into tiny, little hot pieces of gas by talking
• 1:24
  Speaker 1: about all the crazy stuff that exists in our universe.
• 1:27
  Speaker 1: We go way way back to the very beginning of
• 1:30
  Speaker 1: the universe. Talk about how all that happened, how it
• 1:32
  Speaker 1: led to this crazy, beautiful structure that we see today,
• 1:35
  Speaker 1: and what progress we've made in unraveling that structure and
• 1:39
  Speaker 1: understanding the fundamental nature of matter and space and time,
• 1:43
  Speaker 1: and of course what the open questions are still. Yeah,
• 1:46
  Speaker 1: we are here burping out amazing facts about the universe
• 1:50
  Speaker 1: and expelling them out into the atmosphere for all of YouTube.
• 1:54
  Speaker 1: Breathe in to your brains and absorb them and hopefully
• 1:58
  Speaker 1: get nursed with some amazing pruce about the universe. That's right.
• 2:01
  Speaker 1: We want these hot truth to roll over you like
• 2:03
  Speaker 1: lava floating out a volcano. But you know, we're hoping
• 2:06
  Speaker 1: not to burn you too much. Things are getting kind
• 2:08
  Speaker 1: of hot, Dannie, I love it. I love it, and
• 2:12
  Speaker 1: I love it, and who doesn't love lava. But yeah,
• 2:14
  Speaker 1: it's a pretty big universe, and we are just this small,
• 2:16
  Speaker 1: tiny little planet floating in the middle of mostly emptiness,
• 2:20
  Speaker 1: careening through the space, ready to be hit by an
• 2:23
  Speaker 1: asteroid perhaps. And this planet has a long and illustrious history.
• 2:27
  Speaker 1: It hasn't looked the way it currently does for most
• 2:30
  Speaker 1: of its life. We don't think of the Solar System
• 2:32
  Speaker 1: and the galaxy is changing very much. They seems sort
• 2:35
  Speaker 1: of static. But on a cosmological time scale, things are crazy,
• 2:39
  Speaker 1: things are chaotic, things are changing all the time. Yeah,
• 2:42
  Speaker 1: it's easy to think when you look out into the
• 2:44
  Speaker 1: universe and to the stars that things are always the
• 2:47
  Speaker 1: way they are right now. But no, actually, the universe
• 2:49
  Speaker 1: is very dynamic, and it's changing, and it's constantly evolving,
• 2:54
  Speaker 1: which tells us something important about what is gonna be like.
• 2:57
  Speaker 1: If we want to know what the future Earth is
• 2:58
  Speaker 1: going to be like and whether he means can still
• 3:00
  Speaker 1: live on it, we better dig into its past and
• 3:03
  Speaker 1: understand how it got to be such a warm and wonderful,
• 3:06
  Speaker 1: cozy place to live. Yeah, what are we gonna be
• 3:08
  Speaker 1: burping in a hundred million years perhaps or having indigestion
• 3:12
  Speaker 1: with Yeah, So the Earth has an amazing history, and
• 3:15
  Speaker 1: so one part of the Earth that's very important to
• 3:18
  Speaker 1: us is its atmosphere. I count on it every day breathing.
• 3:22
  Speaker 1: It fills me with life every single moment. Really, when
• 3:25
  Speaker 1: you think about it, No, absolutely, we rely on it
• 3:27
  Speaker 1: every single day. Well, we couldn't live without it. It
• 3:30
  Speaker 1: feeds not just us, of course, but all the things
• 3:32
  Speaker 1: that we eat drink. The atmosphere. It's a very complex
• 3:36
  Speaker 1: and elaborate system of pumping gases out of plants and
• 3:39
  Speaker 1: into plants and out of the ocean into the ocean.
• 3:41
  Speaker 1: It's an amazing and complicated system, and it's incredible that
• 3:44
  Speaker 1: it works at all, frankly, and then it's even at
• 3:46
  Speaker 1: all stable. Thank goodness, we haven't because without an atmosphere,
• 3:49
  Speaker 1: we wouldn't be here. We wouldn't just be out of
• 3:52
  Speaker 1: breath and choke to death, but we would also be
• 3:55
  Speaker 1: a pretty toasted thanks to all of the radiation coming
• 3:58
  Speaker 1: from space. That's right, themospheres here. He keeps us warm
• 4:01
  Speaker 1: and acts like a blanket and also acts like a
• 4:03
  Speaker 1: shield protecting us from so many rocks and particles and
• 4:07
  Speaker 1: all sorts of stuff coming from space. So it's a
• 4:10
  Speaker 1: pretty important part of life here on Earth today and
• 4:12
  Speaker 1: hopefully it'll stick around for another billion years or so. Yeah,
• 4:15
  Speaker 1: and we should appreciate it because it wasn't always here
• 4:18
  Speaker 1: on Earth. The Earth didn't always have an atmosphere. There
• 4:21
  Speaker 1: was time and the history of Earth that we were
• 4:25
  Speaker 1: basically naked right out in space nothing to drape over us.
• 4:28
  Speaker 1: That's right. If you build a time machine and you
• 4:30
  Speaker 1: want to see the early Earth, don't neglect to bring
• 4:33
  Speaker 1: your space suit, because if you go back to three
• 4:36
  Speaker 1: four billion years into Earth's history, you're not gonna be
• 4:39
  Speaker 1: able to breathe whatever was on the Earth, if there
• 4:41
  Speaker 1: even was anything. Yeah, and so a big question would
• 4:43
  Speaker 1: be how did it get this way? How is it
• 4:46
  Speaker 1: that we have this beautiful and fresh well depending on
• 4:48
  Speaker 1: where you live, fresh air for us to take in
• 4:51
  Speaker 1: and enjoy and live with. It's a fascinating story that
• 4:54
  Speaker 1: dates way back to the very beginning of the Solar
• 4:56
  Speaker 1: System and involves lots of dramatic pauses like volcanoes and
• 5:00
  Speaker 1: the years and all sorts of other crazy stuff. So
• 5:02
  Speaker 1: today on the podcast, we'll be asking the question where
• 5:09
  Speaker 1: did the Earth get its atmosphere? Yeah? Where did it
• 5:13
  Speaker 1: get its airs? Daniel? It's ambiance, that's right. And it's
• 5:16
  Speaker 1: a very very fine place to hang out. It's very airy,
• 5:21
  Speaker 1: it's very blue and transparent. I love what you've done
• 5:24
  Speaker 1: with the place, really, Dole are burping apparently, I'm guessing
• 5:27
  Speaker 1: maybe does that count as interior design if you're designing
• 5:30
  Speaker 1: an entire planet or is it the still exterior design.
• 5:33
  Speaker 1: I guess it depends. Are you like an alien shopping
• 5:36
  Speaker 1: for planets? Are you like an earthling looking around? I'm
• 5:41
  Speaker 1: imagining the aliens come, they take over the Earth, and
• 5:43
  Speaker 1: they don't really like what we've done with the place,
• 5:45
  Speaker 1: and they want to fix it up a little bit.
• 5:47
  Speaker 1: So they hire some like massive geoengineering firm to do
• 5:50
  Speaker 1: the equivalent of interior design, but for the whole planet.
• 5:53
  Speaker 1: I wonder if that would be like a future career, like, hey, mom,
• 5:56
  Speaker 1: I want to be a geo designer or a geodecorator.
• 6:01
  Speaker 1: That's right, Mars has been using that same shade of
• 6:03
  Speaker 1: red for like a billion years. It's time to pick
• 6:05
  Speaker 1: a fresh color. How about cyan or a nice mango glaba.
• 6:11
  Speaker 1: You need always three words in every name for a
• 6:13
  Speaker 1: shade of paint, you know, wild Mountain, raspberry or something
• 6:17
  Speaker 1: right that, so you can sell more of them, to
• 6:20
  Speaker 1: be honest, because maybe you just sell red and blue,
• 6:22
  Speaker 1: you're out of business. Well, if you're covering a whole planet,
• 6:24
  Speaker 1: I think you're gonna sell a lot of gallons of paint.
• 6:26
  Speaker 1: So yeah, So the Earth didn't always have the atmosphere
• 6:28
  Speaker 1: that we're breathing right now. It used to be a
• 6:31
  Speaker 1: pretty inhospitable place, right, that's right. It used to be
• 6:34
  Speaker 1: a place where humans or animals could not survive because
• 6:37
  Speaker 1: I guess initially, you know, we formed around a brand
• 6:40
  Speaker 1: new Sun and we were just a bunch of rocks
• 6:43
  Speaker 1: and gas kind of gathered together by gravity. Right. Yeah,
• 6:46
  Speaker 1: everything in the whole Solar system, of course, came from
• 6:48
  Speaker 1: the same big cloud of gas and dust to form
• 6:51
  Speaker 1: the Sun and the planets and everything. But the story
• 6:53
  Speaker 1: is a little bit more complicated. Yeah, So we were wondering,
• 6:56
  Speaker 1: as usual, how many people out there know the story
• 6:58
  Speaker 1: of our atmosphere and now how we got to have
• 7:00
  Speaker 1: the air that we have. So, as usual, Daniel went
• 7:02
  Speaker 1: out there into the wilds of the internet to ask
• 7:04
  Speaker 1: people where did Earth get its atmosphere? And so, as usual,
• 7:08
  Speaker 1: if you'd like to participate by answering funny questions with
• 7:11
  Speaker 1: no preparation, please write to me two questions at Daniel
• 7:15
  Speaker 1: and Jorge dot com. Trust me, it's fun. Here's what
• 7:17
  Speaker 1: people had to say. I gotta guess from rocks during
• 7:20
  Speaker 1: the heavy bombardment period when they guesses got released into
• 7:27
  Speaker 1: the atmosphere. But the oxygen and atmosphere, which actually a
• 7:30
  Speaker 1: lot higher today, came from I think it's Sanda bacteria,
• 7:34
  Speaker 1: those rocks in Australia that the first thing is to
• 7:37
  Speaker 1: photosymphasize and actually caused a huge distinction event um And
• 7:41
  Speaker 1: the Earth was just formed. It was hot, and I
• 7:44
  Speaker 1: think there were many chemical reactions going on away her
• 7:46
  Speaker 1: atomic reactions and all. So maybe because of the reactions,
• 7:52
  Speaker 1: I think probably they were just hydrogen and helium in
• 7:54
  Speaker 1: the beginning, but then due to all these reactions, all
• 7:58
  Speaker 1: the different gases will formed. Then maybe that's how we
• 8:01
  Speaker 1: got that atmosphere. Let's say we have lots of nitrogen
• 8:05
  Speaker 1: that prevents everything from blowing up. Then we have some
• 8:08
  Speaker 1: oxygen and some argon. And that's about what I know
• 8:11
  Speaker 1: about earth atmosphere. I can't really tell you where it
• 8:14
  Speaker 1: comes from. I think the atmosphere came from volcanic activity
• 8:20
  Speaker 1: when the Earth was young, and I know that the
• 8:24
  Speaker 1: oxygen came from cyanobacteria producing it when life just got
• 8:29
  Speaker 1: started on Earth. Well the proto or it was very
• 8:32
  Speaker 1: very hot, so I would say that the burning and
• 8:37
  Speaker 1: the temperature itself would cause gases to form that would
• 8:41
  Speaker 1: accumulate around the Earth, being trapped in its gravitational field,
• 8:46
  Speaker 1: and once the Earth cooled, the composition of the those
• 8:51
  Speaker 1: gases must have changed, especially when life started to arise
• 8:56
  Speaker 1: and would start to change the atmosphere and take out
• 9:00
  Speaker 1: garbon dioxide and fill it with oxygen. I think they
• 9:05
  Speaker 1: say Mars used to have an atmosphere. Maybe we stole
• 9:08
  Speaker 1: mars atmosphere here have it on Earth now. Our atmosphere
• 9:12
  Speaker 1: came from all the various eruptions on the Earth. In
• 9:15
  Speaker 1: other words, the Earth's hot are the biggest contributor easy life.
• 9:20
  Speaker 1: You fount organisms reciting the various chemicals from the atmosphere,
• 9:23
  Speaker 1: apart from the atmosphere easily blanged by absorbing common trails
• 9:27
  Speaker 1: and volcano emissions. I'm assuming, like ah, the formation of
• 9:33
  Speaker 1: the Earth, there was a bunch of like dust and
• 9:36
  Speaker 1: rocks and like just surrounding chemicals, and the Earth kind
• 9:41
  Speaker 1: of lumped together. The rocks lumped together created kind of
• 9:44
  Speaker 1: some strong gravity, and like particles and like air particles
• 9:48
  Speaker 1: were like, hey, there's some gravity here. I guess let's
• 9:50
  Speaker 1: like stick around, stick to it. And that's what happened. Alright.
• 9:55
  Speaker 1: A lot of pretty detailed answers. You people have thoughts
• 9:58
  Speaker 1: on the topic. Yeah, they have air, They have a
• 10:00
  Speaker 1: lot of things to say about how we got our atmosphere.
• 10:04
  Speaker 1: That's pretty cool. Do you think it's out there in
• 10:06
  Speaker 1: the popular culture kind of the history of our atmosphere? Yeah?
• 10:08
  Speaker 1: Or you know, maybe it's just so immediate people think
• 10:10
  Speaker 1: about it. They literally breathe it in and out every day.
• 10:13
  Speaker 1: So it's not some like weird, abstruse topic that only
• 10:16
  Speaker 1: physicists wake up late at night thinking about. It's something
• 10:19
  Speaker 1: everybody thinks about. And these days with all the discussion
• 10:22
  Speaker 1: of global warming and climate change, it's something that people
• 10:24
  Speaker 1: really do think about what's in the air and how
• 10:27
  Speaker 1: we can influence it. And I guess it's kind of
• 10:29
  Speaker 1: interesting that nobody was surprised. Nobody was like, what, we
• 10:32
  Speaker 1: didn't always have an atmosphere? Like people seem to know
• 10:35
  Speaker 1: that it came from somewhere. Yeah. Somebody even suggested we
• 10:38
  Speaker 1: stole it from Mars. No way, what is it? Hot
• 10:41
  Speaker 1: airror air? Hot exactly. They're gonna come looking for it,
• 10:45
  Speaker 1: bring it pulled over with a vacuum and suck it
• 10:48
  Speaker 1: all back up. So do you have a receipt for
• 10:50
  Speaker 1: this atmosphere? I do. I just lost a seven billion
• 10:53
  Speaker 1: years ago. Who keeps records that long anyway. Yeah, so
• 10:56
  Speaker 1: it is an interesting story how we got our atmosphere,
• 10:59
  Speaker 1: and so it's interesting to think that that wasn't always
• 11:02
  Speaker 1: the case. You know, we were just a little barren
• 11:05
  Speaker 1: rock floating out in space with some gas. Right. Yeah.
• 11:07
  Speaker 1: It's really a fascinating story because the Earth has had
• 11:10
  Speaker 1: different atmospheres through its history. Like if you took a
• 11:13
  Speaker 1: time machine back to the very very early hot Earth,
• 11:16
  Speaker 1: you'd experienced something very different from if you went back
• 11:19
  Speaker 1: like three billion years ago or one billion years ago.
• 11:21
  Speaker 1: So it's really it's a fascinating, very very dynamic story
• 11:24
  Speaker 1: with lots of twists and turns. Yeah, and it's not
• 11:27
  Speaker 1: just like a different temperature maybe, or like twists in
• 11:31
  Speaker 1: the composition. It's like a totally different set of gas
• 11:34
  Speaker 1: that was enveloping the Earth. Right, Yeah, we have like
• 11:36
  Speaker 1: atmosphere three point oh these days we're not breathing the
• 11:39
  Speaker 1: original atmosphere or even the second atmosphere. We're lacked on
• 11:42
  Speaker 1: the third version of the atmosphere. It's been upgraded twice already. Well,
• 11:46
  Speaker 1: do you think we got it this time or do
• 11:47
  Speaker 1: you think we're do for an upgrade? I'm pretty happy
• 11:49
  Speaker 1: with it. I got no notes like do we have
• 11:51
  Speaker 1: to schedule the update? You know? Can we schedule it
• 11:54
  Speaker 1: for like a billion years from now and when we're
• 11:56
  Speaker 1: not around. Well that's the problem is sometimes you know,
• 11:58
  Speaker 1: you're happy with your version of your operating system and
• 12:00
  Speaker 1: then it updates itself and you're like, no, don't change anything.
• 12:03
  Speaker 1: It was great. Do we have auto update on? Maybe
• 12:06
  Speaker 1: we should turn that off because sometimes things don't work
• 12:09
  Speaker 1: the same, you know, that's the solution of climate change.
• 12:11
  Speaker 1: Rather just untake that box on the atmosphere operating system
• 12:14
  Speaker 1: that says no updates please. All right, everybody stopped breathing
• 12:18
  Speaker 1: for about a hundred years and then we'll get anyone.
• 12:21
  Speaker 1: We're gonna reboot. Yeah, all right. Well, so you're saying
• 12:24
  Speaker 1: this is not our first atmosphere. Um, we're in the
• 12:27
  Speaker 1: third version. So what was the first version of the atmosphere?
• 12:31
  Speaker 1: So the first version in the atmosphere formed when Earth
• 12:33
  Speaker 1: formed itself. As we were saying before, everything in the
• 12:37
  Speaker 1: Solar system came from the same basic constituents. You have
• 12:40
  Speaker 1: this huge cloud of hydrogen mostly in a little helium
• 12:43
  Speaker 1: and trace heavier elements, and that whole thing got sparked
• 12:47
  Speaker 1: into a collapse, which led to the formation of the
• 12:49
  Speaker 1: Sun of course, which is a huge ball of hydrogen.
• 12:52
  Speaker 1: And then the planets gathered together and all basically came
• 12:54
  Speaker 1: out of the same stuff, and you had planets formed
• 12:56
  Speaker 1: because you had like little rocky cores that gathered together
• 12:59
  Speaker 1: and gradually pulled other stuff along with it. And so
• 13:02
  Speaker 1: what was Earth's atmosphere when it first formed, Well, the
• 13:05
  Speaker 1: only gases around really were hydrogen and helium mostly, So
• 13:10
  Speaker 1: just like Jupiter and the Sun and the other gas
• 13:13
  Speaker 1: giants have big atmospheres mostly of hydrogen with a little
• 13:15
  Speaker 1: bit of helium, Earth also had a helium hydrogen envelope
• 13:20
  Speaker 1: around it when it first formed, right because I guess
• 13:22
  Speaker 1: you know, the whole area in space was covered in
• 13:25
  Speaker 1: hydrogen and helium and most of it went into the Sun,
• 13:28
  Speaker 1: but I imagine some of it sort of hung out
• 13:31
  Speaker 1: around the little rocky planets that were forming. Yeah, but
• 13:34
  Speaker 1: not for very long. So what happens is these things
• 13:36
  Speaker 1: are forming and they're collapsing, and there's sort of a race,
• 13:39
  Speaker 1: Like the Sun is gobbling up a huge amount of
• 13:41
  Speaker 1: this stuff, and the gas giants are out there, they're
• 13:44
  Speaker 1: gobbling up a lot of it. And here in the
• 13:46
  Speaker 1: inner Solar System, it turned out to be pretty hard
• 13:49
  Speaker 1: to hold onto any gas because you're competing with the
• 13:52
  Speaker 1: Sun that's slurping up all of the hydrogen as much
• 13:55
  Speaker 1: as it can, and you don't have the gravity that
• 13:57
  Speaker 1: like Jupiter has because the inner part of the Solar
• 14:00
  Speaker 1: System is warmer, so there's no like rock ice to
• 14:03
  Speaker 1: help you build a planet rapidly to grab some of
• 14:05
  Speaker 1: that helium and that hydrogen. So out in the outer
• 14:08
  Speaker 1: part of the Solar System where Jupiter was, you had
• 14:10
  Speaker 1: rocks formed together but also with ice that let them
• 14:14
  Speaker 1: see these larger planets that could hold onto their hydrogen.
• 14:17
  Speaker 1: But here in the inner Solar System, Earth was just
• 14:19
  Speaker 1: sort of like too small to really hang onto its hydrogen,
• 14:22
  Speaker 1: so it was very short lived atmosphere. I guess maybe,
• 14:25
  Speaker 1: like you know, lighter elements like hydrogen and helium, they
• 14:28
  Speaker 1: get more easily sucked in by the Sun and other
• 14:31
  Speaker 1: planets than the rocks that we have, right, that's kind
• 14:33
  Speaker 1: of what happens is that you know, it's so light
• 14:35
  Speaker 1: that they can just leave and get sucked in by
• 14:38
  Speaker 1: the Sun. But whereas the rocks, it's harder for the
• 14:40
  Speaker 1: Sun to have pulled us in that's exactly right. And
• 14:42
  Speaker 1: there was also an opposite effect because once the Sun
• 14:44
  Speaker 1: started burning, it was producing a solar wind, which is
• 14:47
  Speaker 1: a huge amount of radiation that then blew off the
• 14:49
  Speaker 1: rest of our atmosphere. Right, we had no magnetic field
• 14:53
  Speaker 1: yet to protect ourselves from these things. Magnetic field is
• 14:56
  Speaker 1: formed when layers inside the Earth are like mixing and
• 14:59
  Speaker 1: blending and spinning. But the Earth was too young to
• 15:02
  Speaker 1: have like differentiated and had these nicely divided layers that
• 15:05
  Speaker 1: could produce a magnetic field. And so the solar radiation
• 15:08
  Speaker 1: also blew off any gas that we did manage to grab.
• 15:11
  Speaker 1: So initially we had a little bit of gas around
• 15:14
  Speaker 1: our kind of brand new Earth, but then it quickly
• 15:17
  Speaker 1: either left or it got blown away. Yeah, so this
• 15:19
  Speaker 1: first atmosphere was very very short lived. I'm not even
• 15:22
  Speaker 1: really sure you could say they was like settled down
• 15:25
  Speaker 1: before it got slurped up by the Sun and then
• 15:27
  Speaker 1: blown off by the solar radiation. Yeah. I feel like
• 15:30
  Speaker 1: there's a lot of gas and wind in this story
• 15:32
  Speaker 1: is getting a little um you know, gastric here, not
• 15:36
  Speaker 1: just cosmic dig a tums. But there was a lot
• 15:38
  Speaker 1: of stuff going on, like the early solar system was
• 15:41
  Speaker 1: a very chaotic place, and it could have gone in
• 15:43
  Speaker 1: lots of directions. You know, you could have had a
• 15:44
  Speaker 1: planet here or a planet there. The reason we have
• 15:47
  Speaker 1: a planet exactly here depends on a lot of very
• 15:49
  Speaker 1: small chaotic factors that depended just on like the distribution
• 15:53
  Speaker 1: of the initial stuff. But a little bit more clumpy
• 15:56
  Speaker 1: or there, you would have got a different set of planets.
• 15:57
  Speaker 1: All right, So then we had a little bit of
• 16:00
  Speaker 1: hydrogen and helium, but then that quickly went away, and
• 16:02
  Speaker 1: so what was our second atmosphere? So then the Earth
• 16:06
  Speaker 1: was barren, right, we had just a ball of rock
• 16:08
  Speaker 1: with really no atmosphere to speak of. Say this period
• 16:12
  Speaker 1: here where the Earth is like naked. There's just no
• 16:14
  Speaker 1: atmosphere protecting the surface of the Earth from basically space.
• 16:18
  Speaker 1: And you know, interestingly, I talked to some geologists, and
• 16:21
  Speaker 1: they don't see the Earth as naked in that sense.
• 16:24
  Speaker 1: Like for them, the atmosphere is part of the crust.
• 16:28
  Speaker 1: It's just like a different kind of crust, you know.
• 16:30
  Speaker 1: They don't think of it as like the crust ends
• 16:32
  Speaker 1: at the surface and then you have atmosphere. The atmosphere
• 16:35
  Speaker 1: is just sort of like part of the crust. Because
• 16:37
  Speaker 1: there's like constant interchange between the atmosphere and the surface,
• 16:40
  Speaker 1: and it's just like you know, another layer of the earth. Sure,
• 16:44
  Speaker 1: I guess two a geologist. They want it all, they
• 16:46
  Speaker 1: want it all there like the air. That's part of
• 16:48
  Speaker 1: my grant proposal as well. It's part of geology. Of course,
• 16:54
  Speaker 1: humans where also geology. We are part of geology. Absolutely,
• 16:57
  Speaker 1: we are part of the crust. And that's where this
• 16:59
  Speaker 1: outer gas la or the crust that we call atmosphere
• 17:02
  Speaker 1: came from when it was replenished. It was replenished from
• 17:04
  Speaker 1: inside the Earth because volcanoes like the one in Iceland
• 17:09
  Speaker 1: and the other ones around the Earth out gased like
• 17:12
  Speaker 1: internal processes inside the Earth lead to these explosions and eruptions,
• 17:16
  Speaker 1: which can produce enormous quantities of gas. Meaning like was
• 17:20
  Speaker 1: all this gas forms inside of the Earth or it
• 17:23
  Speaker 1: just got trapped as the Earth was sort of forming
• 17:26
  Speaker 1: and all those rocks, actual rocks were coming together. Yeah,
• 17:29
  Speaker 1: it's all in there, and it's all mixed together. You know,
• 17:31
  Speaker 1: you have carbon, you have sulfur, as, you have oxygen.
• 17:33
  Speaker 1: These are all the elemental ingredients of the Solar system,
• 17:37
  Speaker 1: which are then compressed and mixed together. There's a lot
• 17:39
  Speaker 1: of chemistry going on. So these elements all mixed together
• 17:42
  Speaker 1: in the way that's like energetically most favorable. But then yeah,
• 17:46
  Speaker 1: they get spewed up from underneath the earth, and you know,
• 17:48
  Speaker 1: these rocks have gases dissolved in them sometimes and then
• 17:52
  Speaker 1: those can come out when there's less pressure or I
• 17:54
  Speaker 1: guess as maybe as things were sort of churning and
• 17:57
  Speaker 1: coming up from the surface, then the gas was able
• 17:59
  Speaker 1: to escape the rock. Exactly. Large gas bubbles exactly can
• 18:04
  Speaker 1: make their way up through the crust and then emitted
• 18:06
  Speaker 1: by the volcanoes. I mean, that's why volcanic eruptions happen, right.
• 18:09
  Speaker 1: We talked about this in a recent episode on most
• 18:12
  Speaker 1: massive volcanoes in the Solar System. When you have lava
• 18:15
  Speaker 1: that has like a lot of silica dissolved into it,
• 18:17
  Speaker 1: then it becomes like very sticky and it can absorb
• 18:20
  Speaker 1: a lot of gas, and then the gas builds up
• 18:22
  Speaker 1: the pressure and then it erupts and the gas can
• 18:24
  Speaker 1: be freed. Right, And so that's how we got things
• 18:26
  Speaker 1: like water of water, vapor and CO two and hydrogen
• 18:30
  Speaker 1: open in the atmosphere. In that second atmosphere. Yeah, so
• 18:32
  Speaker 1: the second atmosphere is mostly as you say, water, vapor,
• 18:35
  Speaker 1: carbon dioxide, sulfur dioxide, and then a huge amount of
• 18:39
  Speaker 1: just nitrogen. And very importantly, there was no free oxygen,
• 18:43
  Speaker 1: no like O two molecules were floating around in the atmosphere.
• 18:47
  Speaker 1: So this second atmosphere is not something we can breathe
• 18:49
  Speaker 1: at all. It would be totally toxic. You took a
• 18:52
  Speaker 1: time machine back to this volcanic period of the Earth
• 18:55
  Speaker 1: and you took a deep breath as you stepped out,
• 18:58
  Speaker 1: you would die pretty quickly. Great, not a great place
• 19:01
  Speaker 1: to visit. No exactly what bring your space suit, you know,
• 19:04
  Speaker 1: no big deal. Packs of oxygen. Just pack oxygen for
• 19:08
  Speaker 1: fifty years. And there's one other source of sort of
• 19:10
  Speaker 1: basic ingredients for our atmosphere. In those early days, it
• 19:13
  Speaker 1: didn't just come from inside the Earth. There were some
• 19:16
  Speaker 1: deposits from outside the Earth because during this period of
• 19:20
  Speaker 1: chaos in the early Solar System, there's a lot of
• 19:22
  Speaker 1: stuff moving around. The planets were switching positions and passing
• 19:25
  Speaker 1: through the asteroid belt and passing through the asteroid belt
• 19:28
  Speaker 1: in the other direction, which led to a lot of
• 19:30
  Speaker 1: bombardment of the Earth by really big rocks. This is
• 19:34
  Speaker 1: called the late heavy bombardment, and some of those rocks
• 19:38
  Speaker 1: have water, and they have ice, they have other things
• 19:40
  Speaker 1: frozen into them which then evaporated when they hit the Earth. Interesting,
• 19:44
  Speaker 1: so those rocks had other sort of gaseous elements and
• 19:48
  Speaker 1: then when they hit the Earth, they made it into
• 19:50
  Speaker 1: our atmosphere. Yeah, just like we talked about how comets
• 19:52
  Speaker 1: probably replenished the Earth's water in a very same way. Right,
• 19:56
  Speaker 1: Earth had water when it formed, but then it boiled
• 19:59
  Speaker 1: off because we our atmosphere is very hot surface, And
• 20:02
  Speaker 1: we had a whole episode about how comics replenished the
• 20:04
  Speaker 1: Earth's water in the same way. Asteroids and other things
• 20:07
  Speaker 1: probably also replenished part of our atmosphere. Cool. All right,
• 20:11
  Speaker 1: Well let's get into how we actually got breathable oxygen
• 20:14
  Speaker 1: in our atmosphere and how we know all of these things.
• 20:17
  Speaker 1: How do we know the history of our atmosphere? But
• 20:19
  Speaker 1: first let's take a quick break. All right, we're talking
• 20:34
  Speaker 1: about the history of air. Basically, right, where did air
• 20:39
  Speaker 1: come from? And why is it so fresh to breathe? Yeah? Exactly,
• 20:42
  Speaker 1: something it's all around us. It's something that we rely on,
• 20:45
  Speaker 1: so we better understand why it's here and whether it's
• 20:48
  Speaker 1: going away. Yeah. Do you think air is offended when
• 20:50
  Speaker 1: we sneeze or like cough, like you know, get it
• 20:54
  Speaker 1: out of my body? No, I think it's probably grateful.
• 20:56
  Speaker 1: It's like, oh, that's much more interesting. Who wants to
• 20:58
  Speaker 1: be inside of a wind warm human? All right, Well,
• 21:02
  Speaker 1: we had one atmosphere, but then it was blown away
• 21:04
  Speaker 1: by the sun and cosmic rays, and then we had
• 21:07
  Speaker 1: got a second atmosphere that was burped up from the
• 21:10
  Speaker 1: rock inside of the core of the Earth. And this
• 21:13
  Speaker 1: atmosphere had a lot of oxygen, but it which just
• 21:16
  Speaker 1: wasn't free oxygen like it was inside of C O
• 21:19
  Speaker 1: two and H two O or s O two, but
• 21:22
  Speaker 1: it was not something that we could use, like if
• 21:24
  Speaker 1: we breathe it that you wouldn't be able to get
• 21:26
  Speaker 1: that oxygen. Yeah, your lungs can't use that, right, even
• 21:28
  Speaker 1: though there's oxygen c O two, if you step into
• 21:31
  Speaker 1: a room that's pure CEO two, you're gonna fall unconscious
• 21:34
  Speaker 1: pretty quickly. Yeah, not good. Alright, So then that's our
• 21:37
  Speaker 1: second atmosphere. How do we get breathable oxygen? Then breathable
• 21:40
  Speaker 1: oxygen came from life, right, This was terraformed by tiny, tiny,
• 21:45
  Speaker 1: little microbes. But the first oxygen that was produced on
• 21:49
  Speaker 1: Earth wasn't actually from those microbes. The very first came
• 21:52
  Speaker 1: from ultra violet light that hit the Earth's atmosphere. When
• 21:56
  Speaker 1: you v photons, these are just really high energy particles
• 21:59
  Speaker 1: from the Sun and hit H two O molecules of water.
• 22:02
  Speaker 1: They can break it up and you can get ozone
• 22:05
  Speaker 1: formed in the atmosphere. And ozone is just a form
• 22:08
  Speaker 1: of oxygen. It's an O three molecule and it forms
• 22:11
  Speaker 1: in the upper atmosphere and it helps to actually shield
• 22:14
  Speaker 1: us from ultra violet light. So ozone again not something
• 22:17
  Speaker 1: you can breathe, but it's oxygen in the atmosphere which
• 22:21
  Speaker 1: then shielded us from UV which helped life I think
• 22:24
  Speaker 1: evolve a little bit interesting. So, like you just have
• 22:26
  Speaker 1: water molecules H two os there and then when it
• 22:29
  Speaker 1: gets hit by this light, it just breaks up, and
• 22:32
  Speaker 1: I guess breaks up. But then the oxygen doesn't go
• 22:35
  Speaker 1: into O two, it goes straight into OH three. Yeah.
• 22:37
  Speaker 1: In these chemical processes, you always get a mixture of everything,
• 22:40
  Speaker 1: but primarily this is how ozone is formed, and you
• 22:43
  Speaker 1: also get some other stuff forming. You know, you get
• 22:45
  Speaker 1: a little bit of O two but that's only responsible
• 22:47
  Speaker 1: for like one per cent of the oxygen in the atmosphere.
• 22:51
  Speaker 1: That's certainly not enough for us to breathe, all right,
• 22:53
  Speaker 1: but it did sort of form enough O two then
• 22:56
  Speaker 1: that you've kind of had to shield around Earth so
• 22:59
  Speaker 1: that you could, you know, evolve little organism that did
• 23:02
  Speaker 1: make well, it made O three, which is ozone, which
• 23:06
  Speaker 1: is primarily the shield. But exactly it provides a shield
• 23:09
  Speaker 1: to protect us from UV and that can like protect
• 23:12
  Speaker 1: the DNA of delicate little critters as they're evolving on
• 23:15
  Speaker 1: the Earth. All right. So then that's how we got
• 23:17
  Speaker 1: most of our oxygen then, is through bacteria and things
• 23:20
  Speaker 1: like that. Yeah, so bacteria have been around for quite
• 23:23
  Speaker 1: a while, turning away in the oceans of the Earth,
• 23:25
  Speaker 1: and at some point they evolved the ability to do photosynthesis, right,
• 23:30
  Speaker 1: to take sunlight and to combine the energy from sunlight
• 23:34
  Speaker 1: with C O two and water and to produce oxygen.
• 23:38
  Speaker 1: And when this happens, they're essentially producing fuel for themselves.
• 23:41
  Speaker 1: And so this is a really cool little thing that
• 23:43
  Speaker 1: they evolved. It's called cyanobacteria that first evolved this ability
• 23:47
  Speaker 1: to basically drink energy from the sun. And this started
• 23:51
  Speaker 1: about two points seven billion years ago, and that's a
• 23:55
  Speaker 1: very efficient way to turn c O two and H
• 23:57
  Speaker 1: two O into oxygen us. Maybe the you know, in
• 24:01
  Speaker 1: the primordial soup, you know, the earth was you know, inhospitable,
• 24:05
  Speaker 1: but there were little tiny things that could grow in
• 24:08
  Speaker 1: this environment in the oceans, and then that started turning
• 24:12
  Speaker 1: out O two. But that wasn't very beneficial for them, right, No,
• 24:15
  Speaker 1: it actually poisons them. Cyanobacteria are killed by the presence
• 24:19
  Speaker 1: of O two, and so if they make too much
• 24:21
  Speaker 1: of it, they kill themselves off. And again they don't
• 24:24
  Speaker 1: need O too. It's like a byproduct. It's a waste
• 24:26
  Speaker 1: product for them. But they wanted the CEO two, right.
• 24:28
  Speaker 1: Plants breathe CEO two and produce oxygen. Animals like us
• 24:32
  Speaker 1: breathe O two and produce c O two and cyanobacteria
• 24:36
  Speaker 1: they're not plants. They're like the precursors of photosynthesis in plants.
• 24:40
  Speaker 1: So they made a lot of oxygen, but that's not
• 24:43
  Speaker 1: quite the oxygen we breathe today, right, that's right. The
• 24:45
  Speaker 1: oxygen that was made by cyanobacteria originally didn't stick around
• 24:50
  Speaker 1: in the atmosphere because oxygen is super duper reactive. It
• 24:53
  Speaker 1: doesn't usually just hang out like if it can react
• 24:56
  Speaker 1: with anything around it, it will. So you have this
• 24:59
  Speaker 1: fresh earth covered in rocks, and these rocks are very
• 25:03
  Speaker 1: reactive with oxygen. Like imagine a bunch of iron out
• 25:06
  Speaker 1: there and you combine it with oxygen. When you get
• 25:08
  Speaker 1: you get rust. And so basically most of the oxygen
• 25:11
  Speaker 1: produced by the Earth and the first few hundred million
• 25:14
  Speaker 1: years was then breathed in by the rocks on the Earth.
• 25:18
  Speaker 1: They like sucked it all up. Wow, Like the Earth was,
• 25:22
  Speaker 1: you know, shiny and nice looking, and then suddenly these
• 25:25
  Speaker 1: bacteria breathed oxygen and everything rusted. Yeah, it was like
• 25:28
  Speaker 1: hundreds of millions of years where the Earth was getting
• 25:32
  Speaker 1: like a weatherized by all the oxygen that was being produced.
• 25:36
  Speaker 1: And you know how you talk about like free radicals,
• 25:38
  Speaker 1: etcetera in your body maybe causing damage and causing cancer.
• 25:41
  Speaker 1: That's all because of oxygen. Oxygen is very reactive. It's
• 25:44
  Speaker 1: like a crazy thing. It's going to touch and break
• 25:46
  Speaker 1: things near it. And so that's what happened when cyanobacteria
• 25:49
  Speaker 1: started pumping O two into the atmosphere, is that it's
• 25:53
  Speaker 1: starting to get absorbed by all these rocks and break
• 25:55
  Speaker 1: them down and weatherize them. And as you say, rust
• 25:58
  Speaker 1: the entire planet. I guess that's a process that they
• 26:00
  Speaker 1: had to happen, you know what I mean, Like, you
• 26:03
  Speaker 1: can't just have like a shiny, brand new rust free
• 26:05
  Speaker 1: Earth and also have oxygen. Like you're gonna put oxygen
• 26:08
  Speaker 1: in the atmosphere, you have to first, you know, rust
• 26:11
  Speaker 1: everything before you can breathe it. Yeah, everything is going
• 26:13
  Speaker 1: to drink of that oxygen. So if you want enough
• 26:15
  Speaker 1: floating around in the atmosphere for other things like animals
• 26:19
  Speaker 1: to breathe, then you've got to sort of like fill
• 26:21
  Speaker 1: up all the reservoirs out there that are just going
• 26:23
  Speaker 1: to gobble the oxygen so that there's enough to float around.
• 26:26
  Speaker 1: It's sort of like electrons and a semiconductor. You've got
• 26:28
  Speaker 1: to fill up all the lower energy levels so you
• 26:31
  Speaker 1: can have some floating around in the conduction band and
• 26:33
  Speaker 1: conduct electricity. Right, That was the first analogy I was
• 26:36
  Speaker 1: going to go with. I think these cyanobacteria are super amazing,
• 26:43
  Speaker 1: and I love how plants basically co opted them because
• 26:46
  Speaker 1: you know, the cyanobacteria, they evolved photosynthesis, and now when
• 26:49
  Speaker 1: we look inside plants, we see these little objects inside
• 26:52
  Speaker 1: a plant cell that can do the same thing, these chloroplasts.
• 26:56
  Speaker 1: But those things are basically cyanobacteria. They got co opted
• 26:59
  Speaker 1: by plants. The plants like eight them and said, okay,
• 27:02
  Speaker 1: come do that work for me now. So the cyanobacteria
• 27:06
  Speaker 1: should get all the credit for evolving this incredible ability
• 27:08
  Speaker 1: to plants just to like took it over. They're like
• 27:10
  Speaker 1: the managers. Or you could look at it the other way, right,
• 27:13
  Speaker 1: you could say that cyanobacteria, you know, kind of form
• 27:17
  Speaker 1: plants around themselves kind of to do all the hard work.
• 27:20
  Speaker 1: They just have to sit back and get a plan. Exactly.
• 27:24
  Speaker 1: You can look at anything in two ways, I guess.
• 27:26
  Speaker 1: All right, So then we had to wait until everything
• 27:29
  Speaker 1: was rusted before we got our third atmosphere. Yeah, it
• 27:32
  Speaker 1: wasn't until everything was rusted that the oxygen being produced
• 27:35
  Speaker 1: by cyanobacteria and then later also by plants could just
• 27:39
  Speaker 1: sort of hang out in the atmosphere that those levels
• 27:41
  Speaker 1: could climb to the point where like animals could breathe them.
• 27:45
  Speaker 1: And so now we're up to the atmosphere that we
• 27:48
  Speaker 1: have today, which is you know, still mostly nitrogen. It's
• 27:51
  Speaker 1: like seventy eight percent nitrogen, but a good of our
• 27:55
  Speaker 1: atmosphere is O two wow. And it was all made
• 27:58
  Speaker 1: by bacteria and plant basically right like before and like
• 28:03
  Speaker 1: you know, we didn't get that we made that. Yeah,
• 28:05
  Speaker 1: it was made by living creatures. And it took a
• 28:07
  Speaker 1: long long time. Right, So if you're imagining, like let's
• 28:11
  Speaker 1: go to Mars and produce enough oxygen for the atmosphere
• 28:14
  Speaker 1: for us to walk around and breathe, like, it takes
• 28:16
  Speaker 1: a long time. Even when you got like jillions of
• 28:19
  Speaker 1: tiny little machines pumping out of oxygen, it took millions
• 28:22
  Speaker 1: and millions of years. Yeah, it took like four hundred
• 28:25
  Speaker 1: million years actually to be precise. And in a way,
• 28:27
  Speaker 1: they sort of ruined the planet for themselves a little bit, right,
• 28:30
  Speaker 1: or do you think they were co evolving as they
• 28:32
  Speaker 1: were changing the atmosphere. They're definitely co evolving. And cyanobacteria
• 28:35
  Speaker 1: are still with us. They still produce half of the
• 28:38
  Speaker 1: oxygen that we have on the Earth currently, like half
• 28:41
  Speaker 1: of it is made by plants and half of it
• 28:42
  Speaker 1: is made by cyanobacteria. So they're still around in the oceans. Yeah,
• 28:46
  Speaker 1: And so that's how we got our atmosphere and it's
• 28:48
  Speaker 1: not I mean it's a lot, obviously, because we have
• 28:51
  Speaker 1: a lot to breathe, but in terms of the scale
• 28:52
  Speaker 1: of the Earth, it's a really small fliver or a
• 28:55
  Speaker 1: small coating of air that we have on the planet. Yeah.
• 28:58
  Speaker 1: The whole Earth, of course, is six thousand kilometers in radius.
• 29:02
  Speaker 1: The atmosphere where we considerately the atmosphere is you know,
• 29:05
  Speaker 1: just like thirty or fifty kilometers high, so it's a
• 29:08
  Speaker 1: very very thin ver near It's like a very thin
• 29:12
  Speaker 1: coating of water on a billiard ball. Yeah, because like
• 29:15
  Speaker 1: what the Earth is, what like ten thousand kilometers in
• 29:18
  Speaker 1: radius or something like that kilometers in radius, but only
• 29:23
  Speaker 1: the last thirty kilometers are atmosphere. Yeah, And where exactly
• 29:28
  Speaker 1: you say the atmosphere and depends really just on where
• 29:30
  Speaker 1: you want to say it ends. Some people say it's
• 29:32
  Speaker 1: up to a hundred kilometers because you know, it falls
• 29:35
  Speaker 1: off very smoothly as you go out into space. But
• 29:39
  Speaker 1: of the mass of the atmosphere, like most of the
• 29:41
  Speaker 1: stuff in the atmosphere is within the first thirty kilometers.
• 29:44
  Speaker 1: The geologists also claim space as geology as well. They're like,
• 29:47
  Speaker 1: you know, I just keep going. Their atmosphere is geology,
• 29:51
  Speaker 1: space is geology. Galaxies geology. When they say we are
• 29:55
  Speaker 1: one with the universe, they mean it literally, like the
• 29:57
  Speaker 1: universe is just all part of the Earth. We are one,
• 30:00
  Speaker 1: and that one is you got below the surface and
• 30:03
  Speaker 1: above the surface, and it's just two parts to the
• 30:05
  Speaker 1: whole universe. Or no, it's it's all one big surface geologist.
• 30:11
  Speaker 1: But it's actually quite interesting. There are lots of like
• 30:13
  Speaker 1: really fascinating layers to the atmosphere. Like you might imagine
• 30:17
  Speaker 1: as you go higher up, the air gets thinner and
• 30:19
  Speaker 1: thinner and colder and colder until you get out into
• 30:22
  Speaker 1: space and it's like super freezing. But actually the temperature
• 30:25
  Speaker 1: like varies and it gets hotter and colder and hotter
• 30:27
  Speaker 1: and colder as you go up really depending on like
• 30:29
  Speaker 1: the composition or did you just get like pockets of stuff, Yeah,
• 30:32
  Speaker 1: depending on the composition. They're all these fascinating layers. Like
• 30:36
  Speaker 1: as you go up, you know, you go above like
• 30:38
  Speaker 1: Mount Everest, for example, things get colder and colder and
• 30:40
  Speaker 1: thinner and thinner. But then when you get to like
• 30:43
  Speaker 1: this ozone layer, things turn around and start to get hotter.
• 30:46
  Speaker 1: As you go past the stratosphere, things actually start to
• 30:49
  Speaker 1: get hotter and hotter and hotter, not quite back up
• 30:52
  Speaker 1: to like surface levels, but you know, getting kind of
• 30:55
  Speaker 1: warm before they turn around again and then get colder
• 30:59
  Speaker 1: as you go up through the is a sphere and
• 31:01
  Speaker 1: then it turns around again and it actually gets hotter
• 31:04
  Speaker 1: and hotter as you go into space, right, Yeah, because
• 31:07
  Speaker 1: I guess those are the layers that are absorbing a
• 31:09
  Speaker 1: lot of the sunlight. Is that what's happening. They are
• 31:12
  Speaker 1: absorbing a lot of the sunlight and they are evaporating, Right,
• 31:15
  Speaker 1: what's going to be leaving the Earth? What's going to
• 31:17
  Speaker 1: be making it out there to the higher levels are
• 31:20
  Speaker 1: the faster moving particles, and so the Earth is sort
• 31:22
  Speaker 1: of like differentiating. We are losing our atmosphere constantly. We
• 31:26
  Speaker 1: had a whole podcast about that, and primarily we lose
• 31:29
  Speaker 1: the hotter atoms, the faster moving ones. So while it's
• 31:32
  Speaker 1: not very dense up there, there's not a lot of heat,
• 31:35
  Speaker 1: you have faster moving particles, which are the ones that
• 31:38
  Speaker 1: are escaping, and so it technically it is hotter. Yeah,
• 31:41
  Speaker 1: the hotter ones that are always the first ones to leave,
• 31:43
  Speaker 1: for sure. And there's also sort of like radioactive elements
• 31:46
  Speaker 1: out there in our atmosphere too, right, Like some pretty
• 31:49
  Speaker 1: not saying stuff out there. Yeah, absolutely, one percent of
• 31:52
  Speaker 1: our atmosphere is actually are gone. You know, You've got
• 31:54
  Speaker 1: like seventy percent nitrogen oxygen, and then one percent are gone,
• 32:00
  Speaker 1: which is sort of weird. It's this radiogenic argon forty
• 32:03
  Speaker 1: which comes from the decay of potassium forty. And it's
• 32:05
  Speaker 1: really interesting actually, because mostly which you have out there
• 32:08
  Speaker 1: in the universe, like made by stars is aregon thirty six,
• 32:13
  Speaker 1: which is, you know, a different isotope of argon that's
• 32:15
  Speaker 1: made in the fusion inside stars. But here on Earth,
• 32:18
  Speaker 1: most of the argon in our atmosphere is argon forty,
• 32:21
  Speaker 1: which comes from this radioactive decay. And it took people
• 32:24
  Speaker 1: a long time to figure out that that's where it
• 32:26
  Speaker 1: came from and how it worked, and it was a
• 32:28
  Speaker 1: fun puzzle that was solved a few decades ago. And
• 32:30
  Speaker 1: there's also some pretty interesting elements like krypton and neon
• 32:34
  Speaker 1: and methane, And our atmosphere is not just like nitrogen
• 32:36
  Speaker 1: and air and oxygen. Do you remember that everything in
• 32:39
  Speaker 1: our solar system came from those same basic soup of ingredients.
• 32:43
  Speaker 1: Inside the Sun, of course you have fusion making new
• 32:45
  Speaker 1: heavy elements, but outside of the Sun, everything is just
• 32:48
  Speaker 1: a mixture of the same elements that went in. Right,
• 32:50
  Speaker 1: we have no fusion happening on Earth. All the elemental
• 32:54
  Speaker 1: like crypton or neon, or hydrogen or oxygen or all
• 32:57
  Speaker 1: the other weird stuff that we have came from fusion
• 32:59
  Speaker 1: in side some star somewhere else. Our solar system is
• 33:03
  Speaker 1: a population one solar system, which is the third generation
• 33:06
  Speaker 1: in our universe. So all of these atoms of oxygen
• 33:10
  Speaker 1: and other stuff were formed inside a star billions of
• 33:13
  Speaker 1: years ago, which then blew up and led to the
• 33:16
  Speaker 1: formation of this dust cloud, which eventually became our solar system.
• 33:19
  Speaker 1: That means we're all a little bit cryptonian, right, a
• 33:22
  Speaker 1: little bit. Yeah. All of these things that were made
• 33:24
  Speaker 1: of that we're breathing, that we're relying on, all came
• 33:27
  Speaker 1: from somewhere else, were fused inside a star somewhere, and
• 33:30
  Speaker 1: so that's how we got our atmosphere through a lot
• 33:33
  Speaker 1: of burpaying by the Earth and surviving some winds and
• 33:36
  Speaker 1: a lot of bacteria making it. And that's how we
• 33:38
  Speaker 1: got the air that we have today. And thank goodness,
• 33:40
  Speaker 1: because it smells pretty good. You could have smelled that, right,
• 33:44
  Speaker 1: you guys. We're lucky that the Earth smells good. It
• 33:46
  Speaker 1: probably did smell pretty bad for long periods. You know,
• 33:49
  Speaker 1: they're probably some pretty stinky times when Earth the stinker scene,
• 33:53
  Speaker 1: I think it's called, you know, teenagers they never smelled,
• 33:58
  Speaker 1: Introduce them to deodorant, and then things pick up from there.
• 34:01
  Speaker 1: All right, let's get into how we know this interesting
• 34:05
  Speaker 1: history of our atmosphere and what it could mean for
• 34:08
  Speaker 1: the future of Earth and people breathing in it. But first,
• 34:11
  Speaker 1: let's take another quick break. All right, we're talking about
• 34:26
  Speaker 1: the history of our atmosphere and we're kind of in
• 34:29
  Speaker 1: our third atmosphere, is what you're saying, Like we you know,
• 34:32
  Speaker 1: we're not in our starter home, we're not in our
• 34:34
  Speaker 1: second home. We're like in our our vacation home. Unless
• 34:37
  Speaker 1: we've been working on this for a while. We're living
• 34:39
  Speaker 1: the dream right now, breathing the dream. We are we
• 34:42
  Speaker 1: are And I love hearing those kinds of stories when
• 34:44
  Speaker 1: you look around and you don't really know what the
• 34:47
  Speaker 1: history of the Earth is, and then you discover through
• 34:49
  Speaker 1: various like really subtle clues and awesome detective work that
• 34:53
  Speaker 1: things have changed, that the Earth used to be really
• 34:55
  Speaker 1: really different. Because you know, your naive assumption is like
• 34:58
  Speaker 1: I don't know the earth form that had it to
• 34:59
  Speaker 1: have spirits always been like this, that's the simplest story,
• 35:02
  Speaker 1: and science always prefers the simplest story. But it's super
• 35:05
  Speaker 1: fun when you discover that the story is more complicated
• 35:08
  Speaker 1: than it has twists and turns. But you can't just
• 35:10
  Speaker 1: like tell that story. You gotta find the clues. You've
• 35:12
  Speaker 1: got to discover that story. Yeah, because that's a big question.
• 35:15
  Speaker 1: It's like, how do we know all these details? I
• 35:18
  Speaker 1: feel like that was a very detailed story of how
• 35:20
  Speaker 1: we got our atmosphere, but there was nobody around really
• 35:23
  Speaker 1: to sort of measure the oxygen or to see what
• 35:26
  Speaker 1: was happening. So how do we know all of these things? Yeah,
• 35:29
  Speaker 1: we have to look for clues in the geological record,
• 35:32
  Speaker 1: and so the rock record, like rocks that were formed
• 35:35
  Speaker 1: five hundred million years ago or a billion years ago
• 35:37
  Speaker 1: or two billion years ago, how they formed, and which
• 35:41
  Speaker 1: kinds of rocks formed tell us about what atmosphere there
• 35:44
  Speaker 1: was around, because some kind of rocks can only form
• 35:47
  Speaker 1: in the presence of oxygen, and other kind of rocks
• 35:49
  Speaker 1: can only form if there's no oxygen. So as you
• 35:52
  Speaker 1: look at the rock layers, you can look like back
• 35:54
  Speaker 1: in time and get a sense for like what was
• 35:57
  Speaker 1: going on, right, because I guess the rocks are stead
• 36:00
  Speaker 1: of changing, right, they're churning, they're flipping over. They sort
• 36:03
  Speaker 1: of build up as they're growing, right, So then then
• 36:06
  Speaker 1: that's where you get the record. Yeah, if you drive
• 36:08
  Speaker 1: through the desert, for example, and you see canyons, etcetera,
• 36:11
  Speaker 1: you can see these stripes in the rocks. Right, where
• 36:14
  Speaker 1: do those stripes come from? Those are layers of rocks
• 36:17
  Speaker 1: that have been laid down over millions and billions of years.
• 36:20
  Speaker 1: As you say, the surface is like active stuff is
• 36:22
  Speaker 1: coming out from underneath and then creating new layers which
• 36:25
  Speaker 1: get laid down and then pushed down, and sometimes those
• 36:28
  Speaker 1: layers then break and get pushed back up to the
• 36:30
  Speaker 1: surface and revealed, and so we can see that history.
• 36:33
  Speaker 1: That's why like dinosaurs are buried in the earth, because
• 36:36
  Speaker 1: we're constantly laying down new layers of rock on top
• 36:39
  Speaker 1: of the old ones. And so that's super cool because
• 36:42
  Speaker 1: it's basically like a snapshot of what was going on
• 36:45
  Speaker 1: on the planet back in the day. And as you
• 36:47
  Speaker 1: can look at those rocks and see patterns in them,
• 36:50
  Speaker 1: then you can get a clue is to like what
• 36:51
  Speaker 1: was going on in the atmosphere because all those rocks,
• 36:54
  Speaker 1: as we were saying before, interacted with the atmosphere that
• 36:57
  Speaker 1: leaves an imprint on the rock basically like if they
• 37:00
  Speaker 1: was a lot of oxygen or not, or other kinds
• 37:02
  Speaker 1: of gases than the rocks a little different. Yeah, And
• 37:05
  Speaker 1: one of the most important clues are these formations called
• 37:09
  Speaker 1: banded iron. And these are really beautiful. You should google
• 37:12
  Speaker 1: them and check them out because they are basically these
• 37:14
  Speaker 1: rocks with these thick red stripes in them, this oxidized
• 37:17
  Speaker 1: iron stripes, And that tells us a lot about when
• 37:20
  Speaker 1: this oxygen nation event happened, when the cyanobacteria started pumping
• 37:25
  Speaker 1: oxygen into the atmosphere, because it started to bind with
• 37:29
  Speaker 1: the iron that was out there and get weatherized and
• 37:31
  Speaker 1: make these layers and layers of basically rushed inside the
• 37:35
  Speaker 1: Earth's atmosphere. So you can look back at these first
• 37:38
  Speaker 1: earliest layers of rust and pinpoint when oxygen starts to
• 37:42
  Speaker 1: be produced. That makes me think of like a heavy
• 37:44
  Speaker 1: metal band or something bad. Iron first rust. There you go,
• 37:49
  Speaker 1: red rusted rage. It's super cool because it's sort of
• 37:53
  Speaker 1: like rings on a tree because you can see these bands.
• 37:57
  Speaker 1: It's not just like, oh, oxygen turned on, start to
• 38:00
  Speaker 1: be produced, and then everything after that is just rusted iron.
• 38:03
  Speaker 1: You have these bands where it's like rusted iron and
• 38:05
  Speaker 1: then none, and then rusted iron and then none, like
• 38:08
  Speaker 1: turned on and off and on and off. You can
• 38:10
  Speaker 1: be like, oh, look at the earth just burped here
• 38:13
  Speaker 1: or just past wind. Yeah, what happens is that this
• 38:16
  Speaker 1: oxygen that these bacteria produced is actually poisonous to them, right.
• 38:20
  Speaker 1: Cyanobacteria do not like a lot of oxygen, so they
• 38:24
  Speaker 1: produced a bunch of oxygen and some cases there was
• 38:27
  Speaker 1: like a lot of iron around in the water to
• 38:29
  Speaker 1: grab that oxygen and then sink back down to the
• 38:32
  Speaker 1: ocean floor and form a band. But sometimes the cyanobacteria
• 38:35
  Speaker 1: would produce too much oxygen it couldn't all get breathed
• 38:39
  Speaker 1: in by this iron, and then they would poison themselves
• 38:42
  Speaker 1: and like kill themselves off, and then they wouldn't be
• 38:44
  Speaker 1: producing as much anymore, and so there wouldn't be as
• 38:46
  Speaker 1: much iron deposited. But then the conditions were favorable again
• 38:49
  Speaker 1: for a cyanobacteria, which would then grow back and produce
• 38:52
  Speaker 1: a huge amount of oxygen, which would they create another
• 38:55
  Speaker 1: band and sort of this sort of cycle effect where
• 38:57
  Speaker 1: they overproduced and kill themselves and then grow. That's kind
• 39:00
  Speaker 1: of what's happening to us right now. I mean, we
• 39:02
  Speaker 1: are creating so much c O two. Every time we
• 39:04
  Speaker 1: breathe out, we create c O two, And so we
• 39:06
  Speaker 1: didn't have all these other processes to repleashes the O two,
• 39:09
  Speaker 1: we would be basically poisoning ourselves, right, breathing ourselves out
• 39:12
  Speaker 1: of a planet. Yeah, we could have a sort of
• 39:14
  Speaker 1: similar effect we have, like human civilization builds up and
• 39:17
  Speaker 1: then poisons itself with c O two, and then you
• 39:20
  Speaker 1: have like a com period on the Earth for a
• 39:22
  Speaker 1: million years, while you have like small bands of humanity surviving,
• 39:26
  Speaker 1: rebuilding civilization to poison ourselves. Again. I can see your
• 39:30
  Speaker 1: brain just writing the sci fi novel there. I think
• 39:32
  Speaker 1: I've read that one. But I guess maybe a question
• 39:34
  Speaker 1: is like, how do we, you know, correlate that to time.
• 39:37
  Speaker 1: Like we can see these bands in the rock, but
• 39:39
  Speaker 1: how do we know that band took place or was formed,
• 39:43
  Speaker 1: you know, three hundred million years ago or six billion
• 39:46
  Speaker 1: years ago? How do we get that calibration of the
• 39:48
  Speaker 1: rings in the tree? Oh yeah, great question. It's like
• 39:50
  Speaker 1: how do we know the age of any rock? You know?
• 39:53
  Speaker 1: And I remember thinking about this as a kid, wondering,
• 39:55
  Speaker 1: like what does it even mean the age of a rock?
• 39:58
  Speaker 1: You know, because like love is lava, rock and melt
• 40:01
  Speaker 1: or flow. It's like asking how old water is. But
• 40:03
  Speaker 1: when you talk about the age of a rock, you're
• 40:06
  Speaker 1: not talking about like when the chemical elements or even
• 40:09
  Speaker 1: the elements inside the rock were formed, because that happened
• 40:11
  Speaker 1: inside a star billions of years ago. We're talking about
• 40:14
  Speaker 1: like when this crystal was created. Because rocks are a
• 40:17
  Speaker 1: solid formation of these elements, right, like cooled together to
• 40:21
  Speaker 1: form a solid object. So you can measure that age
• 40:24
  Speaker 1: of the rock, which is when did this thing become
• 40:26
  Speaker 1: a solid object? How long ago was this thing fluid?
• 40:29
  Speaker 1: When did it transition to becoming solid? And you can
• 40:32
  Speaker 1: measure that because when that happens, it captures things inside
• 40:35
  Speaker 1: of it, these crazy little crystals, and those crystals, some
• 40:38
  Speaker 1: of them are radioactive and they like decay very slowly
• 40:41
  Speaker 1: over time. You can measure how many of those are
• 40:44
  Speaker 1: and calibrate them. And that's when you do to measure
• 40:47
  Speaker 1: the age of rocks. I see, like when the rock forms,
• 40:50
  Speaker 1: they capture like a taking clock almost inside of them.
• 40:53
  Speaker 1: It's sort of similar to carbon dating, which we can
• 40:55
  Speaker 1: use to age like things that were once alive because
• 40:59
  Speaker 1: they have certain ratios of carbon in them. But here
• 41:02
  Speaker 1: we're talking about things that are much much older. So
• 41:04
  Speaker 1: we use these radiometric dating methods based on the natural
• 41:08
  Speaker 1: radioactive decay of things like potassium and carbon to date
• 41:12
  Speaker 1: these ancient ancient events. I would different rocks. That's a
• 41:17
  Speaker 1: terrible joke. I apologist for them. So yeah, so that's
• 41:20
  Speaker 1: how we know then, how the history of our atmosphere. Yeah,
• 41:23
  Speaker 1: because we can look at this record and so that's
• 41:26
  Speaker 1: one piece of evidence is these banded iron formations. You
• 41:29
  Speaker 1: know this that's a big influence on like our civilization
• 41:33
  Speaker 1: because Detroit, for example, is in a location where there
• 41:36
  Speaker 1: used to be an ocean with huge colonies of cyanobacteria
• 41:40
  Speaker 1: depositing lots of bands of iron and so like that's
• 41:44
  Speaker 1: why a huge fraction of the steel deposits available on
• 41:48
  Speaker 1: Earth are like near Detroit, and that's why we have
• 41:50
  Speaker 1: a car industry near Detroit because of this cyanobacteria. So
• 41:54
  Speaker 1: I love these like connections from the ancient times back
• 41:58
  Speaker 1: to like you know, modern zivilization and even politics. They
• 42:01
  Speaker 1: always talk about the rust belt, right exactly, they should
• 42:04
  Speaker 1: be talking about the cyanobacteria belt. Really, yeah, nobody wants
• 42:07
  Speaker 1: to be in that political group. But this also lines
• 42:11
  Speaker 1: up with other pieces of evidence. Again, we look into
• 42:14
  Speaker 1: the record to see what could happen with oxygen and
• 42:17
  Speaker 1: what could happen without oxygen. And there are other minerals
• 42:20
  Speaker 1: like pyrite, this thing called fools gold, which can only
• 42:23
  Speaker 1: form when there's no oxygen in the atmosphere. It's it's
• 42:26
  Speaker 1: oxygen around and the elements that would otherwise make pyrite
• 42:29
  Speaker 1: tend to make other things instead. And so you can say, like, oh,
• 42:32
  Speaker 1: pyrite was only created until about a certain date several
• 42:36
  Speaker 1: billion years ago. So that's another clue. And I imagine
• 42:38
  Speaker 1: also there's a lot of it is sort of theoretical,
• 42:40
  Speaker 1: kind of based on models of how the Earth form, right,
• 42:43
  Speaker 1: for example, we can only go back so much. But
• 42:46
  Speaker 1: these methods, like when you're talking about before, like you know,
• 42:49
  Speaker 1: our early or first atmosphere getting blown away by the
• 42:53
  Speaker 1: solar wind. That's you know, we don't have evidence for that,
• 42:55
  Speaker 1: but you know, from what we know how the planets
• 42:58
  Speaker 1: get formed, that's probably what happened and we know the
• 43:00
  Speaker 1: solar wind exists. We can measure the solar wind, and
• 43:02
  Speaker 1: so we can model what would happen if we didn't
• 43:05
  Speaker 1: have a magnetic field. So yeah, well there's a lot
• 43:07
  Speaker 1: of things we can do to validate those models. But
• 43:09
  Speaker 1: absolutely there's modeling going on all over the place in
• 43:13
  Speaker 1: all of these studies. And you know, we try to
• 43:15
  Speaker 1: make assumptions and then they would trying to find ways
• 43:17
  Speaker 1: to check them and to validate those assumptions. Absolutely. You know,
• 43:20
  Speaker 1: another thing we do is we think about, like how
• 43:22
  Speaker 1: life could have evolved. A lot of the basic chemical
• 43:25
  Speaker 1: building blocks of life couldn't have formed if we had
• 43:29
  Speaker 1: oxygen in the atmosphere, right, So life produced oxygen, but
• 43:33
  Speaker 1: in lots of cases it's inhibited by the presence of oxygen.
• 43:36
  Speaker 1: That kind of life that me and you are, this
• 43:38
  Speaker 1: aerobic kind of life that relies on oxygen, is fairly
• 43:41
  Speaker 1: late showing up in the evolutionary record. And so if
• 43:45
  Speaker 1: we had had oxygen, like outgassed by those volcanoes, we
• 43:48
  Speaker 1: might not have formed life, right because the earliest life,
• 43:52
  Speaker 1: like our ancestors, were anaerobic, right, they didn't like oxygen. Yeah,
• 43:57
  Speaker 1: they're poisoned by oxygen, and not just the life itself,
• 44:00
  Speaker 1: like the chemical building blocks, a lot of those amino
• 44:02
  Speaker 1: acids that they need to just like bump together in
• 44:04
  Speaker 1: a weird way in the primordial soup. Those couldn't have
• 44:07
  Speaker 1: formed if there was oxygen, because oxygen is just like
• 44:10
  Speaker 1: so excited. It bonds to everything and it prevents other
• 44:13
  Speaker 1: things from happening. So if we've had oxygen around, we
• 44:16
  Speaker 1: could have made those building blocks, and maybe life itself
• 44:18
  Speaker 1: wouldn't have started sort of crazy. So it's a good
• 44:22
  Speaker 1: thing we didn't have oxygen then, but it's a good
• 44:25
  Speaker 1: thing that we have it now, Yes, exactly. And it's
• 44:28
  Speaker 1: like such a delicate balance, right. We needed oxygen to
• 44:31
  Speaker 1: not be around, and then we needed these other life
• 44:33
  Speaker 1: to exist for a while, and then to produce a
• 44:35
  Speaker 1: bunch of oxygen so that we could evolve. It's a
• 44:37
  Speaker 1: crazy story, right, but I guess it's all one constant evolution. Right.
• 44:42
  Speaker 1: You can't just ask, like, we wouldn't be here if
• 44:44
  Speaker 1: we didn't have oxygen, but maybe some other anaerobic beans
• 44:47
  Speaker 1: would be here having a podcast breathing out less hot
• 44:51
  Speaker 1: air than we are, at least less mellie air. Maybe. Yeah, absolutely,
• 44:55
  Speaker 1: it's just that our particular path relied on all of
• 44:57
  Speaker 1: these things happened in a particular order. Really, if things
• 45:00
  Speaker 1: have been different, you know, you could have evolved life
• 45:03
  Speaker 1: in lots of other different ways. Well, I guess I'm
• 45:05
  Speaker 1: glad that it worked out this way. And it's good
• 45:08
  Speaker 1: to know these things also because not just because maybe
• 45:11
  Speaker 1: we want to change other planets, but we may also
• 45:14
  Speaker 1: want to find other planets like ours that have an atmosphere,
• 45:18
  Speaker 1: and so knowing these things might help us find or
• 45:21
  Speaker 1: maybe our second or fourth home or retirement home maybe
• 45:24
  Speaker 1: for humanity. Yeah, we are just now able to probe
• 45:28
  Speaker 1: the atmospheres of planets around other stars by seeing how
• 45:32
  Speaker 1: light passes through them as they block their stars. And
• 45:36
  Speaker 1: understanding how a planet forms its atmosphere and how the
• 45:38
  Speaker 1: atmosphere evolves is really crucial to answering the question like
• 45:42
  Speaker 1: is there one out there we could land on? Because
• 45:45
  Speaker 1: there might be a planet out there in the habitable zone,
• 45:47
  Speaker 1: meaning it's like warm enough to melt water on the surface,
• 45:50
  Speaker 1: but there might not be an atmosphere, and that's not
• 45:53
  Speaker 1: terribly useful because you can take millions and millions of years.
• 45:57
  Speaker 1: Even if you like plants cyanobacteria in the water on
• 46:00
  Speaker 1: an alien planet to produce enough oxygen. So it's a
• 46:03
  Speaker 1: really interesting question, like how long does this take? Is
• 46:06
  Speaker 1: it unusual on Earth? Could happen faster on other planets?
• 46:09
  Speaker 1: Is it already happening on other planets out there right
• 46:12
  Speaker 1: now with primitive life producing oxygen. It's a really interesting
• 46:15
  Speaker 1: and deep question and one that might be really important
• 46:18
  Speaker 1: for the future of humanity. Yeah, you don't want to
• 46:20
  Speaker 1: pack up all of your things move halfway across the
• 46:23
  Speaker 1: gaxy and then when you get there, that wouldn't be good.
• 46:26
  Speaker 1: And also for our neighbors. You know, Elon Musk talks
• 46:29
  Speaker 1: a lot about moving to Mars and making it a
• 46:31
  Speaker 1: second home for humanity, but it's going to take a
• 46:33
  Speaker 1: long time before you can walk on the surface of
• 46:36
  Speaker 1: Mars and like take a deep breath and survive, not
• 46:39
  Speaker 1: to mention even enjoy it. All right, Well, it kind
• 46:42
  Speaker 1: of makes you grateful for the air that we have,
• 46:43
  Speaker 1: because you know, this is kind of the only thing
• 46:46
  Speaker 1: we have to breathe and the only place in our
• 46:48
  Speaker 1: Solar System and maybe in our galaxy that we know
• 46:50
  Speaker 1: of right now where we could comfortably walk around outside
• 46:54
  Speaker 1: and breathe the air. I'm very grateful. I'm full of it.
• 46:57
  Speaker 1: You're full of hot air and cold air and all
• 46:59
  Speaker 1: the air. I'm putting them all on at the same time,
• 47:01
  Speaker 1: and burping them and doing other contributions to the air
• 47:05
  Speaker 1: all at the same time, and speaking Icelandic very badly
• 47:08
  Speaker 1: into a microphone for other people to hear. All right, Well,
• 47:12
  Speaker 1: that's the history of our atmosphere and we hope you
• 47:15
  Speaker 1: enjoyed that. Thanks for joining us, See you next time.
• 47:25
  Speaker 1: Thanks for listening, and remember that Daniel and Jorge explained.
• 47:28
  Speaker 1: The Universe is a production of I Heart Radio or
• 47:31
  Speaker 1: more podcast for my heart Radio, visit the I Heart
• 47:34
  Speaker 1: Radio app, Apple Podcasts, or wherever you listen to your
• 47:38
  Speaker 1: favorite shows. Ye