Translator: Denise RQ
Reviewer: hila scherba So this is Lithium, It's got 3 electrons, 3 protons
and usually 4 neutrons, and you probably don't think
about it very much. Umm, right? Show of hands,
who doesn't think about Lithium? You probably don't think
about it very much, you probably know
that it's used in a medication, you know that it's used in batteries, and... that's it. A couple of years ago, I was sitting
in my room, very emo and depressed, and listening on repeat
to the song "Lithium" by Evanescence. (Laughter) You might, if you're slightly older,
know the song "Lithium" by Nirvana, and it struck me as odd that these two intense emotional bands
had both written songs about Lithium, and this isn't really a thing
that happens, right? OK, people write songs
about Gold and Platinum, but there is no Beryllium song,
there is no Boron song. Why this one? And I started digging, and it turns out that Lithium is one
of the strangest elements in the Universe and I want to tell you about it, starting with the fact that it probably
shouldn't be here on Earth at all. So, you've all heard the phrase
"we're all stardust." So what that means is
that way back in the early Universe there was a giant cloud of Hydrogen gas, and somewhere in that cloud of gas
a little bit became denser than the rest, and the gravity of that part
started pulling it in further and further, and as more accumulated,
it's started pulling in faster and faster, and eventually the whole thing
began collapsing and heating up and eventually it heated up
to the point where nuclear fusion ignited and the force of explosion
from that fusion counteracted the implosion from gravity
and that's what a star is. Then, inside that star, the Hydrogen,
element number one with one proton, began fusing with
other Hydrogen, one plus one, and you end up
with element number two, Helium. And that went on
for hundreds of millions of years and then eventually,
the Hydrogen was used up, it stopped burning, collapsed,
heated up more to the point where it could fuse Helium,
element number two. So, one plus one gave us two,
element two plus element two gives us element six, that's right. And that's because of Quantum Mechanics. The best thing about being a physicist is anytime you want to skip
a long, involved explanation, you just go, "Because Quantum Mechanics." So, the Helium burns into element
number 6, which is Carbon, as well as 7 and 8, Oxygen and Nitrogen, and this process continues, and you start
creating more and more elements, all of the ones we know,
up to Iron, number 26. Once it hits Iron, it can't burn anymore, the star shuts off, and if it's big enough
it collapses more, and as it collapses, it rebounds and explodes as a Supernova,
the brightest thing in the Universe, which can outshine a galaxy
while it's exploding. In the hot plasma from
that supernova explosion is so intense that all of the heavier elements
can be formed from nuclear fusion, all of the Gold, and the Silver,
and the Xenon, and the Uranium are made there along with all the others. Throughout this, all these elements
are being scattered out into the cosmos, and as they are, they find
another cloud of Hydrogen gas, and this one begins
to collapse into a star. That star ignites, and around it, these heavier elements form
into rocks, and asteroids, and planets, and that's what Earth is. And that's why we're all stardust. Now, a couple of things about this. First, we skipped Lithium,
skipped number 3. So where does it come from? It's actually even weirder than that, if you had some Lithium,
and you took it and you put into a star, it would melt and go away. So not only do stars not produce Lithium,
they destroy it, if it existed before. It turns out it comes
from a number of places. A small amount of it does come from stars,
in that Supernova explosion, and the other ways that stars die in,
but a lot of it comes from... - think about what did I mean
when I said, "We're all stardust"? - Turns out that's not quite right, because in your body,
you're about 10% Hydrogen, and if you remember, the star started
from a primordial cloud of Hydrogen gas, where did that come from? And that, it turns out,
came from the Big Bang itself. So, moments after the Big Bang, everything was a hot dense soup
of undifferentiated nuclear matter. It eventually cooled, and as it cooled,
little droplets of nuclear matter formed, and those droplets became protons,
which are the nucleus of a Hydrogen atom. And it goes on. During that hot era, the protons can fuse
with each other and they can make Helium, then, unlike stars in the early Universe,
that Helium can fuse to make Lithium, and it's different there
because Quantum Mechanics. (Laughter) But some Lithium is formed
in the Big Bang, it's not a lot, it's 1 part in
ten billion, but that's enough. And a lot of that comes into this clouds
of gas and ends up here on Earth. The fourth place that we get Lithium
from, is actually my favorite, it goes by the wonderful name
'cosmic rays foliation' - it's a lovely word -
and what it means is Out in the Universe,
cosmic rays are accelerated, these are protons and electrons
and positrons and other things, and they come screaming across the cosmos, occasionally, one of them will intersect
with the Earth, I say occasionally, there is a tremendous
number of these things, we're being bombarded by them constantly. Sometimes, these cosmic rays come
in through the atmosphere, and they find a big nucleus,
like a Nitrogen or an Aragorn, and they hit that nucleus,
they shatter it; the shattered bits of that giant nucleus
form other elements, sometimes Lithium. So the Lithium we have
here on Earth, like us, is part stardust, part primordial dust,
and part Earth dust. And now, you're probably
sitting there thinking, I have thrown a blizzard
of sciences at you, I have talked about
cosmology and astronomy and nuclear physics and particle physics,
and I'm not going to stop, because now it keeps going. The Lithium nucleus binds
through electromagnetism to electrons to form the Lithium atom itself,
and once it's formed the Lithium atom, it combines with other elements
through chemistry to form compounds, and those compounds get
into all the systems in the Earth, they're dissolved in the ocean,
and evaporated, and they're deposited in salt flats, and some of them get into
the underwater water waves. The geochemistry and geohydrology
take that Lithium through the Earth and deposit it in certain places,
like Bolivia, and Chile, and Argentina. And it's fascinating
how the geochemistry means that it ends up in Bolivia
and not in Topeka or Brooklyn. And once it's there,
and we find those deposits, we can take tools
we've made of iron and steel, and we can dig it up
and use it for things. It's one of the lightest elements
that can be used to make a battery, so it powers all of our mobile devices. It can be used in ceramics, lubricants,
fireworks, and the shattered It can be used to make Tridium,
which is important for nuclear fusion, both power plants and bombs. And because of all
these technological applications, the geochemistry that deposited it gives away to the geopolitics
of mining ethics and colonialism. And then we can take some of that Lithium and combine it with Carbon and Oxygen
to make Lithium carbonate, and we take the Lithium carbonate,
put it together with a white powder, and mill it into pills,
that we can then ingest; and once they are inside us,
they go into our stomach where they are dissolved
and enter the blood stream. Once there, the Lithium atom moves away
from the rest of the compound, crosses the blood brain barrier and enters sodium and potassium
channels in our neurons. And once it does that, through a process
which I cannot even say quantum mechanics because we do not know how this works, it becomes an incredibly
effective medication for certain psychiatric disorders,
particularly bipolar, for which it can bring down
the highs of mania, and lift up the lows of depression. This one atom, number 3, which possibly
came from the Big Bang itself, has a profound affect on what we think
of as our personality, on our psychology. And this of course is why Nirvana
and Evanescence wrote songs about it. (Laughter) And I was listening to this and thinking,
this changes my view of what my brain is. I'm not a dualist, I don't think that the mind
is some special mystic force that's separate from the brain. If you ask me, "does the mind
come from the brain?", I would say, "Yes, of course it does.
I'm a good scientist, " But I don't think that, I don't feel that. I'll say things like: "My brain hates me,"
or "My brain is making me do this," as if it is separate from who I am. This is why I like the story of Lithium, because it makes visceral, something that
before I had only known in the abstract. That the same forces,
that shape our personality, are the same as the forces the shape
everything else in the Universe. And I really like these stories
that connects us to the science around us. There is a myth, you probably
know this about Isaac Newton. He is sitting under a tree, and an apple
falls and hits him on the head. And as the apple falls and strikes him, he realizes the force that is pulling
the apple down, gravity, is the same as the force that is keeping
the planets in orbit around the Sun. And when he realizes this,
he realizes that there is no difference in the laws of nature on Earth
and the laws of nature in the Heavens, and when he does that,
he erases the distinction between the Earth and the Heavens, brings Earth up to the Heavens
and the Heavens down to Earth. Now that is a myth in two senses. First, it didn't happen (Laughter) not quite like that; he did see an apple,
it did not hit him on the head, and he certainly did not have
a complete, sudden realization. But it's a also a myth in the sense
that it's the kind of story we tell to explain to ourselves
how the Universe works, what our place in it,
and how we should live in that world. And this particular myth
is really important to scientists because this is the myth that says,
"if I do an experiment here, and I do an experiment over here,
I am going to get the same answers." That the laws of nature
are not capricious. In that sense, it's the myth that gives
meaning to everything that scientists do. And so we keep telling the story,
over and over again because it locates us in the world, we might not realize that is
what we're doing when we tell it, but that's how myths function. We don't normally think of stories
about science as being important for our personal identity,
or our cultural identity. There are few exceptions like the debates
over evolution, or climate change, but other than that, we think
that the chemistry of Lithium, or biochemistry of Lithium even,
seems like this very clinical thing, that is very disconnected
from who we are as people. And that's why I like the Lithium story. Again, it makes very visceral
this thing that was abstract. I think if we're serious about
living in a scientific world, if we're serious about living in the world
that has been revealed to us by science, then we need to be telling
more of these stories, we need the story of the atom from
the Big Bang can affect our personality. We need stories that cut across all
the different sciences and the humanities, the stories that show us that everything
out here, really is, deeply connected. Thank you. (Applause)
