Do you ever think about what your body is made of?
Like not the blood, and the skin, and the bones,
and the gross stuff, but the atoms, the elements?
As Carl Sagan once said, the very matter that makes us up
was generated long ago--
--and far away in red giant stars.
A blade of grass, as Walt Whitman said,
is the journey work of the stars.
Man, that Carl Sagan guy.
I don't know who he was, but he sure
was good at talking to people, huh?
But have you ever wondered where the elements
in that blade of grass came from, like actually came from?
What kind of star stuff are we?
Carl was pretty specific.
The nitrogen in our DNA, the calcium in our teeth,
the iron in our blood, the carbon in our apple pies
was all made in the interiors of collapsing stars.
And he said that famous line, we are star stuff.
But even though that sounds like sunshine,
narwhals, and rainbows, how do we know, Carl Sagan?
How do we know where these elements came from,
especially the heavy ones?
Where'd I come from?
I have questions.
[MUSIC PLAYING]
Welcome back to Uno Dos of Trace, my little star shines.
Thanks for tuning in.
And like I said, old Carly Say-say
was pretty specific about the elements
in our body coming from stars.
And stars are amazing because, you know, they keep us alive,
give us something to look at when we look up.
But organic life is made of six elements specifically--
hydrogen, carbon, oxygen, nitrogen, calcium,
and phosphorus.
So if you look at our old periodic tabla--
excelente-- hydrogen is uno, carbon
is six, nitrogen's seven, oxygen eight, phosphorus 15,
and calcium is 20.
But that doesn't cover everything, right?
What about all of these?
There are so many.
There are over 100.
Where'd all these come from?
Sagan would say stars.
Stars make heavy elements.
They squish things together.
Hydrogen get squished into helium,
helium gets squished into carbon.
The heaviest element stars can make is iron,
and according to a new study from the National
Institutes of Natural Sciences, Carl
was being a little presumptuous.
A brazen presumption, actually.
These researchers say, quote, "it's not yet identified
where and how elements heavier than iron in the universe
have been made--" iron.
And that only gets us to number 26 on the old periodic tay-tay.
Seriously, platinum and gold, for example.
Where'd the universe get that sparkle?
And as much as I want to shout stars at you
for the next five minutes because I would love that,
I called my friend Dr. Ian O'Neill, a specialist
in heliodynamics, or suns.
Because in the world of science media,
a British accent will always help with trustworthiness.
Please don't tell him I did a fake British accent though,
thanks.
Hi Trace, thanks for having me on the show.
Thanks for being on the show.
So we're talking about stars and specifically
where the heavy elements in our universe--
or our planet, and our bodies, and everywhere else--
came from.
Our star, which is basically like a starter.
It basically does the smaller elements
to produce larger elements up to iron by the time it's dead.
And then you have supernova, which are basically
larger stars which collapse, and explode,
and are able to produce heavier elements beyond the iron
because they detonate and they basically
just force these particles together
at incredibly high energies.
And then you've got these collisions of neutron stars
that have these r-process elements that are formed
and we're able to actually see them for the first time.
How do you make a neutron star, then?
If our star makes the light elements,
and supernovas make the kind of middleweight elements,
and neutron stars make the super heavy elements,
how do you make a neutron star?
Well, so a neutron star is born after a massive star
has gone supernova.
So supernovas can produce black holes
if the star is significantly massive.
But if you have a more massive star that runs out of fuel
and then collapses in on itself, it will produce a supernova,
and it can produce a neutron star because basically it
just produces this very dense material in its core
and from the shock of the explosion-- which itself
produces heavy elements-- it will
leave behind this remnant called a neutron star.
Neutron stars are the densest stuff in our universe.
One teaspoon of neutron star material
weighs 6 billion tons--
one teaspoon.
So stars will go nova, big stars go supernova,
neutron stars go kilonova, which is an amazing indietronica band
name, I have to say.
They think that the core of a neutron star
is made of superconducting superfluids-- fluids that
flow without friction.
They're really interesting.
And they have so much pressure in the center of these stars--
in the core--
that there's no actual elements there,
it's just a soup of subatomic particles.
I mean, mainly neutrons, because the name neutron star,
but when two of these really dense heavy balls
a matter collide you get a kilonova releasing
all of the material on their insides
and they explode out into the universe.
And it generates light.
Kilonovas are really cool because they
happen when you get these two neutron stars that
travel through space.
They somehow find each other and get
trapped in their own gravity and are spiraling in
and smashing into each other.
And then they produce this extremely intense explosion
called a kilonova.
Now on Earth, we see those as these bright flashes
of light in the distant space.
And those are called gamma ray bursts
that we're all kind of familiar with.
And only recently through some really cool research
into gravitational waves and detecting
these gamma ray bursts that we're actually
able to attribute these gamma ray bursts with kilonovas.
So now we know these short gamma ray
bursts are caused by the collision of neutron stars.
And so this is like the densest stuff in the universe,
and that makes sense.
If you're trying to make a heavy element
you need a lot of stuff, right?
Right.
Astronomers were able to combine the gravitational wave
signal, which was produced by these two
massive objects colliding.
So it's basically ripples in spacetime.
So those ripples in spacetime, which
travel at the speed of light, ripples through our planet
at approximately the same time gamma
ray burst detectors detected the gamma ray
burst and the kilonova produced by this neutron star merger.
At the same time, so now you've got gravitational waves
with a gamma ray burst.
We were also able to work out exactly--
pinpoint exactly where it happened in space,
and it happened 130 million light years away.
And elements when they are burned or energized in general
give off specific wavelengths of electromagnetic energy,
and we can pick that up.
So sucking in the light from kilonovae
and using this computer model, they
can determine the elements that are coming out of those stars
and they found abundant heavy elements like gold,
and platinum, and earth metals like neodymium.
So a supernova happens and the iron
flies out into the universe and smooshes into other iron,
crashing into stuff, and making heavier elements.
I mean, that's what we think.
But otherwise if we want more specific than that--
So we're in a golden age of astronomy
because we've theorized that these things can happen,
and we've got so many really cool hypotheses as to where
these elements come from.
But now we're actually getting the reality,
we're actually getting real observations of the sites
of heavy element production.
And that's helping models on Earth,
that's helping experiments on Earth,
and they're able to recreate the conditions of these neutron
star mergers and actually produce these heavy elements,
these radio isotopes in the lab on Earth.
So this is incredible.
I mean, you add this to the fact that humans
can create heavy or really, really
heavy elements that actually don't exist in nature
for long periods of time.
This planet is kind of special in the universe
because we're producing these cosmological events that we
shouldn't be able to do.
It just doesn't-- these things don't actually get created
in nature, but we're very, very clever monkeys.
We were able to do these things.
So yes, it's very exciting to actually connect our evolution
with these cosmological events.
It's very fun.
Thank you for being on the show, Ian.
You are the best, you can find Ian over
on Twitter @astroengine, link is in the description.
About 4 billion years from now, our sun
is going to have burned through all of its hydrogen.
Then it's going to start in on the helium
that it was making when it was smooshing
the hydrogen together, and the output is
going to be carbon and oxygen.
After the helium is burned through,
the carbon and oxygen are going to get fused,
and the core will eventually be making neon.
Want to know what color the sun's going to be?
Just look at red neon lights because that's just
excited neon gas in a clear tube.
And even further in the future, iron
will become the core of a star.
And that's it.
Why?
Because iron doesn't give out any more energy by fusing
it with more iron or anything else.
It just gives energy out by fission.
You have to break it to get the energy out of it.
It's the top of the mountain, if you will.
So a supernova is needed to smoosh iron into other things
to make heavier elements.
But what about the heaviest natural element?
Back to the periodic tabla.
Uranium, number 92.
Every element heavier than uranium
can also exist in nature, we just don't commonly see them.
And admittedly, it's based on the limited experience of us
on our tiny planet in our tiny corner of our giant galaxy,
and we've never left this planet.
But still it's-- you know, it's experience.
In case you're wondering-- and you're a curious person who
watches this show, so I assume that you are--
to create an element, you essentially
copy what we just learned from Ian happens in nature.
We smoosh heavy elements together in the hope
that we make a new element.
There are no lasers, or blue glowing coconut
flavored triangles, but sometimes
broken pieces of other elements, they
stick to make new ones-- just not usually for very long.
So German and Russian teams have tried this,
they did it in 2012 with element 119,
and it's been tried again and again since.
They smashed ionized titanium into Berkelium,
and they theorized the new 119 would be magnetically
reactive and radioactive.
So they put powerful magnets to pull it out
of any of the collisions and detectors that
could tell whether or not it showed up, and it didn't work.
There are still experiments looking for element 119,
the largest elements likely possible are up to 126
according to models.
So there's a lot more to discover,
we just haven't seen them yet.
So when Sagan says that we're star stuff, what
he means is our bodies, our planet,
our stars come from the stellar furnaces
of long dead other stars.
And it's a diverse group of stars, too.
I mean oxygen, and carbon, and phosphorus,
you can make those in little teeny stars.
But the rest of the planet, you need heavy elements for that.
And for those heavy elements you need supernovas and neutron
stars.
And this is just one theory as to why it took so long for life
to evolve, because every supernova
is at the end of a star's life and they
live for millions or billions of years.
So this cycle has to happen where the first stars form
after the Big Bang, and they smoosh together things
into helium, and eventually the helium gets smushed
into other things, and then it gets exploded out
into the interstellar medium.
And eventually other stars form, and they pick up
this created stuff that existed from the first stars,
and they use it in their fusion, and then they explode,
and then so on, and so on.
Stars are born, they die, they supernova.
And every time this happens, they get heavier elements--
or so we think.
Eventually, all that stuff found its way
to our little corner of this little galaxy
and coalesced into our little solar system.
The whole planet is made of bits of exploding stars.
Your whole body is made of bits of exploded stars--
even neutron stars.
And as Marty McFly might say, that's heavy, Doc.
But it just makes old Sagan right again.
Makes good sense to revere the sun and star, as he said,
because we are their children.
Thanks for watching Uno Dos of Trace, everyone.
Make sure you come find me over on Instagram, on Twitter,
you can support us over on Patreon
and help make more of Uno Dos of Trace and Hello Science.
Super excited for you to see these future episodes
I'm working on.
I'm going to be out of the studio a little bit
in the next couple of weeks to try and film some stuff.
I'm really excited about it!
OK, so with that, I'm Trace and I'll see you in the future.