When will the Sun explode?

How long can we enjoy the sunshine before we need a new star?

Learn more about your ad-choices at https://www.iheartpodcastnetwork.com

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:04):
All the stars in the universe are constantly exploding nuclear bombs. Um,
that's a little frightening. We'll go out there and warm
your toes on the you know, the thermonuclear fire of
a huge bomb that's constantly exploding. That sounds it's like
a contain and continual explosion. Yeah, you want to see

(00:24):
a nuclear bomb go off, Go outside and look at
the sun. I mean, not directly yourself. You just made
this advice. The advice. Yeah, we'll ask them to edit
it up. Hello, I'm Jorge and I'm Daniel, and this

(00:50):
is our show. Daniel and Jorge explained the universe. Explain
the entire universe, especially all the stars inside of it. Now,
I noticed, Jorge, every time you introduce your our show,
you're about to say R and Daniel explaining the universe,
and then you have to correct yourself and you're like, no, actually,
we're still bitter about that. You know. My real job,

(01:13):
you know, is as a particle of assist and I
have five thousand collaborators. And when we write a paper,
we put everybody's name on the paper. And the policy
has put everybody's name alphabetical by last name, regardless of
who contributed more or less or whatever. Somebody decided they
didn't want to have the argument, let's just make it alphabetical.
And what that means that there's some grad student who's

(01:34):
first author on like every paper. Wow, it's like him
or her, and it's sort of makes some famous and
also sort of infamous because people grumble about it. No pressure,
no pressure. That's right in the Glaring Spotlight. But you know,
today's episode actually relates to that, to Glaring Spotlights, because
today we're talking about something very close to home. We're

(01:56):
talking about how long the sun is going to live?
How long do we have before it burns out or
explodes or snuffs out? How many more projects can Daniel
and Jorge or Jorge and Daniel do arguing about order
until life on Earth is extinguished because the star is gone.

(02:18):
Do you have time to clean out your garage or
do that thing you've always wanted to do? Right? That's
that sequel to We Have No Idea, our book now
available from Penguin Random Pass. That's right. So if you're
currently procrastinating doing something you should do, then you're actually
gonna learn something today about how much time you have
left to procrastinate right, so, um, yeah, let's let's jump

(02:41):
in for we as usual, asked people on the street
how long they thought that the sun would keep burning
until the question is, how long do you think the
sun will keep burning? Play along at home, think of
your answer, and then listen to these random on the
street interviews. How long do you think our son is
going to continue to burn for? How long? I think

(03:03):
a few billion years? I don't know. Millions, No, not millions, sorry,
probably a long time. I hope a long time. Like,
doesn't this affect your plans? Come on, you should know
this al right? Well, I guess the first thing is
that nobody seemed really concerned. That's right, nobody's rushing home
to finish up something before the sun snuffs out or

(03:26):
explodes that like what, the sun is gonna stop burning?
At some point? Everyone seemed to know about the idea
that the sun won't shine forever. Oh that's a good point.
I never even considered that that I would be the
one informing people by asking the question that the sun
was not gonna last forever? Oh my god, what what
are you saying? I know everybody seems to know that already,

(03:48):
but maybe nobody seemed concerned because everybody's answers were very
far off in the future. Nobody said, I don't know
ten years years. Everybody's like random big number. Everybody feels
like it's just so of far off in the future,
it doesn't matter. Well, let's maybe take a step back,
like how do stars even inform? Right? Like I imagine
out in space there's stuff like dust and little bits

(04:11):
of rock, and at some point the gravity pulls them together,
like there's some nearby each other until they clumped together,
and first it's a giant rock, and then it's an
even bigger rock, and then it just gets more massive,
and at some point what happens. Yeah, but it's not
mostly rock. Stars are mostly made out of gas, mostly
out of hydrogen. So in the Big Bang, most of

(04:31):
the stuff that was formed after the Big Bang was hydrogen,
a little bit helium and a few heavier elements, but
mostly you just have huge clouds of gas formed in
the early universe, and then gravity takes over and gravity
slowly pulls those things together, as you said, and accumulates
these gas clouds, and then those gas clouds get pulled
together by gravity and they get squeezed together more and

(04:53):
more until it gets denser and denser, and eventually it
gets squeezed together by gravity enough that it starts to burn.
And by burn, I mean fuse. You have like nuclear
bombs going off because of the pressure inside these big
clumps of hydrogen. Right, what do you mean they get
dense and like just more and more hydrogen atoms just
kind of bunch up because they're all attracted to each
other by gravity. Yeah, it's kind of like a runaway process.

(05:16):
I mean, if you had a perfectly smooth universe filled
with hydrogen atoms, then no one would want to go
anywhere because you'd be tugged in every direction at the
same strength. Everybody would be attracted to everybody else equally. Yeah,
that sounds like a good party, right, universe party, we're
all attracted to each other. Yeah, party, that's right. Hey,

(05:38):
you know the analogy works because we're gonna talk about
fusion and fusion and things are going to get hot.
You don't want your relationship to go supernova later on.
In relationship advice from an astrophysicist, Yeah, yeah, today we're
just knocking out that. To that advice, children go out
and look at the sun. People have explosive relationships. This

(05:58):
is our last episode, by the way, guys, right, so um,
But there were little areas in the universe early on
they were a little denser than others, and that's just
because of quantum fluctuations. And then those areas were heavier
because there's a little bit more stuff, you're more heavier,
you have more gravitational pull than anywhere else. So then
you start to attract more stuff, and the heavier you get,
the denser region becomes, the more gravity it has, the

(06:22):
stronger its ability to pull more stuff in. And then
it gets heavier and heavier, and it's a runaway process
where pretty soon it's accumulating stuff faster and faster. So
you can imagine like at some point a giant ball
of really compressed gas, right, Like maybe at the edges
it's not as compressed, but in the middle, it's just
everything is trying to push it together, right, But it
doesn't immediately fuse because hydrogen atoms are also repelling each

(06:45):
other at the same time, right, Like they're attracted by gravity,
but they're repelling each other by other forces. That's right.
Fusion is not easy to pull off. I mean, we're
trying to do it in experiments all the time here
on Earth. Like it's like trying to squeeze too many
together they are on the same polarity, right, yeah, or
trying to make two kids share one ice cream or something.
Not a good idea. But so it's the repelling there

(07:06):
have been attracted by gravity, repelling by electromagenic forces. But
at some point, if you get them close enough, then
another fource kicks in, right, and that's what kind of
fuses them together. Is that true? Yeah? And that's when
you access the strong nuclear force, and that fuses them together,
and the strong nuclear force very strong then therefore its name.
And when you do that, you release a huge amount

(07:27):
of energy. And so that's what all of the energy
is coming from, is just these hydrogen atoms fusing together.
That's right. Almost all the light from all the stars
in the universe is from hydrogen fusing together and creating
all that energy and shooting it out into space. But
is it like a kind of like a chain reaction,
like you know, like a nuclear bomb, like one explosion

(07:47):
causes the next explosion. Is that what's happening inside a
star or is it just just the pressure just kind
of makes like popcorn just makes all these kernels pop
pop up. So on Earth, it's a chain reaction you're
thinking of like fission. Fission is the opposite process, and
you break in nucleus up and it sprays out and stuff.
I'm here. You just have a huge blob of hydrogen

(08:07):
in the core and it's being squeezed by the outside
and everything around it, and it gets really hot. And
you know that's true of every object, like even the Earth.
What's at the center of the Earth. It's not cold
at the center of the Earth. It's hot, and it's
hot for lots of reasons, but one major reason is
that it's being squeezed by gravity. All that rock on
the center of the Earth is being squeezed by all
the rock on the outside, and it gets turned into lava. Right.

(08:30):
Why is lava hot Because it's been squeezed by gravity.
Gravity is pretty powerful if you give it enough time
and stuff. So are cloud of hydrogen. It just kind
of suddenly ignites or is it kind of like burns
begins to burn slowly, like as the star go like
or is it is it kind of a long process? No?
I think it ignites pretty quickly once it gets going

(08:51):
um and it and what happens depends on how big
it is. Um So, if you have a huge blob
of gas, right and it forms an enormous ball of
of of hydrogen, then it can burn really brightly and
not for very long. If it's smaller, then it doesn't
get to be big enough to burn like you know,
like the Earth or Jupiter or something. Jupiter is like

(09:12):
a star that never got started because it just wasn't
big enough for the core to start burning. Oh, you
need more stuff to m basically weigh down and squeeze
the middle. That's right. Yeah, the core of Jupiter is
not being squeezed enough. I mean, it's massive gravitational pressure.
You would not like it it. Do not recommend it
as a destination for your occasion, but against yeah, that's right.

(09:35):
There are some common sense warnings on this show. But
it's not hot enough to start nuclear fusion. Okay, so
then things say squeeze and you got a sun. Suddenly
you have this big ball of gas that's burning in
the middle. That's right, it's burning through nuclear fusion. It's
turning hydrogen into helium. Okay, cool, And I want to

(09:56):
talk a little bit more about that. But first a
quick break. Yeah, that's how stars are born, um, not
just in Hollywood and they and then it just keeps
burning for a long time, right, until all the hydrogen
turns into helium. Yeah, that's exactly right. You have fuel

(10:19):
and you burn that fuel, and when you're done burning
that fuel, you're done. But the interesting thing is that
the output of fusion is helium. Right. But and so
what happens is that you accumulate helium at the core
of these stars and then if it keeps going, if
it gets big enough, then you can start to fuse helium.
Oh and then that's um, it's like it it goes

(10:40):
into secondary fuel burning mode. Yeah, exactly, burning helium because
you confuse helium into the element with number four, which
I embarrassingly can't even remember, is that lithium. Okay, so
we're talking about the what happens to the star, and
that's at some point it makes it turns all the
hydrogen into helium and eventually into iron. And that's kind
of when that's what kind of when a supernova happens, right, Yeah, Well,

(11:03):
it doesn't necessarily happen. Have to be a supernova depends
on the mass of the star and so let's talk
just to be specific about a star like ours, you know,
the sun, and any any object that's like about up
to eight times the mass of the Sun is going
to have an experience like our sun. And so what happens.
It starts to burn hydrogen, like we said, and then
the hydrogen gets and the core gets burned up and

(11:23):
you get helium, and then you start to burn the
hydrogen on the shell, and then the star starts to grow.
It gets bigger, like physically larger in space. And the
reason is that you're now burning the hydrogen on the
outside and that the burning there is pushing stuff out.
It's like the radiation pressure is making it grow. So
the sun will keep burning and then it will expand

(11:45):
and it will cool, so it'll start to get larger
and it will turn into a red giant. So giant
meaning gets bigger and red because it changes color because
the color is related to the temperature, right, like, the
cooler it is the right like it's kind of counterintuitive.
The colder it is the star is the redder it is.
But then the hotter it is, the bluer it looks, right, Yeah,

(12:05):
And that's related to the wave length of those lights
of that light. Yeah. Yeah, Like if you could found
you press fast forward on life on Earth, you would
see the Sun is this yellow dot. But eventually you'll
see it grow and grow redder and then grow and
eventually will take over our entire sky. And at some
point we'll just snuff us out. That's right. Eventually we
will be in the sun. Earth. Earth will just get

(12:28):
like eaten up by the Sun. Yeah, exactly. But that's
bill again, billions of years in the future. It's like
three billion years in the future. Three billion years. Yeah,
and so before but before we even get snuffed up,
you know, it'll get pretty hot and we wouldn't want
to be around anyway. So first the oceans boil and
then we get snuffed up. Yeah, and then that's that's

(12:49):
like the last phase before the Sun dies. And then
it's mostly used of its fuel, and you know, it's
like a fire. You use of the fuel and then
the fire goes out. So everything turned to iron. Maybe
it's not every star that can make iron, depends on
the size of it. Mostly iron is made in much
bigger stars. So our star is not big enough to
make iron, so will probably make helium and a little
bit of lithium and a few other things. Oh, I see.

(13:11):
So some stars are bigger, so they have more pressure
so they can cook iron, but but ours cannot exactly.
Ours is not by far one of the biggest stars
in the universe. It's relatively modest. Yeah, And and then
when it burns off all the hydrogen sort of on
the outside, then it'll go out, and what we'll left
be left with is something they call a white dwarf,

(13:32):
which is basically just meaning a big cool blob, something
that's not burning anymore of what um. It's just sort
of the leftover stuff. You know, you have enough elements
there to sit there there. It's hot and so it's
sort of glowing, but it's not actually burning anymore. And
you'll have some helium and maybe some lithium and just
be like a dense blob, but it won't be bright

(13:52):
the same way, and it will cool and eventually become
a black dwarf, which means basically a big lump of rock,
like just a giant meter right, yeah, though mostly made
of like frozen helium. Frozen helium for real. Yeah, because
mostly what mostly what the Sun is is burning hydrogen
into helium. And again some of that helium will get
burned into heavier stuff, but most of it won't, I think.

(14:12):
And so this is going to be like a giant
ice ball the size of what. Oh, you'll be small,
you'll be smaller than the current Sun. It's just the core, Yeah,
just the core is left over because all the other
stuff is blown out when it turned into a red giant.
But yeah, some significant fraction of the mass of the
Sun is going to end up left over as a
white dwarf and then a black dwarf. Yeah, exactly. And

(14:33):
you know that has a future. It could be that
that um then gets clustered together later on and becomes
part of a new star. You know a lot of
the stuff that's in um in our star and in
the Earth used to be inside of a star. And
so you know, everything that we're that we're made out
of is a remnant from a star that died. So
if it wasn't for stars and these fusion furnaces making

(14:55):
the heavier elements, then there wouldn't be anything else to
make stuff out of. It would all just be hyde
in the helium. And so it's gravity squeezing this stuff
together over billions of years that makes the heavier elements,
and mostly in the bigger stars that you get up
to like iron. You know, the bigger stars can do
more exciting stuff. Like our son is not going to
go supernova, is just not big enough. But a bigger
star could have enough mass that it collapses and it

(15:16):
pushes it together and it can create a supernova and
then two weird things, either a black hole or a
neutron star, which I think is one of the weirdest
things in the universe. So it's more of an implosion
than an explosion. Actually, yeah, yeah, yeah, it's pretty crazy stuff.
So you're saying that's when that's when the heavier elements
can eat, right, yeah, in some of these supernovas, because

(15:37):
you have heavy stuff flying around um and and it
collides and it forms even heavier stuff. Yeah. And then
but the heaviest stuff, like we were saying earlier, gold
and all that stuff gets formed when the when two
of those remnants collide, like say you have one really
massive star lives its whole life, has a great time,
blows up, turns into a neutron star, and another one

(15:58):
does the same thing, and then the two neutron stars
are orbiting each other and eventually, because they're so massive,
they pull each other together and they collapse and they
collide into each other, and it's in that collision that
you can form the really heaviest stuff. So all the
super heavy metals in the universe are made when neutron
stars die, and that's why they're so rarities that you

(16:18):
need these crazy events just to make gold and titanium
and all these elements. Right, yeah, that's right. But it's
crazy that we have that stuff on Earth yet, right,
I know, we have it here on Earth, and it's
like the leftovers these incredible cosmic events that happened billions
of years ago and then got sprayed out into the
universe and with enough time for them to like have

(16:39):
a whole new life. You know. I love that everything
in the universe is getting recycled, right, Like our solar
system didn't even start forming until you know, five billion
years ago, which is nine billion years into the party. Right, Yeah,
let's talk about that, But first let's take a quick break.

(17:03):
Right now, is when the sun is like looking over
the hot sexy sun in the next solar system and
looking corvette, right, yeah, it's wondering, like do I look
like a big fat red giant. Tell me I still
look small like a nice little yellow dwarf. Yeah, exactly.
And one thing that I think is really interesting is
that the smallerest star is the longer it lives. The

(17:24):
bigger star is the shorter it lives. And the first
stars in the universe were massive, they were incredible, and
so they didn't live for very long. Like those first
stars we talked about, none of those are around anymore.
None of the stars that are in the universe now
our first generation stars. They're all second, third, fourth generation,
that kind of stuff. All the stars were seeing the
night sky in like the pictures of galaxy. They're all Um.

(17:47):
None of those are among the first stars that were
formed about a hundred million years that's the big Bang. Yeah,
it's only recently people scientists even saw the light from
those first stars. It's really hard to see. Um. You
have to use the infrared because the universe was so
dense back then. But yeah, our star is made out
of leftover bits from other stars earlier that burned and
exploded and wow and recombined. Right, And eventually you're saying,

(18:10):
our big ice ball of the Sun is going to
recombine with something else maybe and for but you can't
do this forever, you know, Like there's a limited amount
of hydrogen and you need hydrogen to to have these
reactions to start. Eventually things get yeah, things get denser
and denser, and you're run out of fuel. So like
think about the Milky Way galaxy. It's got enormous blobs

(18:33):
of of hydrogen gas. Still it's still making stars, but
eventually it's going to run out, and then it's gonna
stop making stars. And those stars are going to burn
for a while, but they're not going to burn forever.
So eventually everything's going to be like iron and heavier metals. Yeah, yeah,
and then things will get dark. Things are going to
get rocky. Things are rocky, that's right. But some of

(18:54):
these stars, some of these stars are gonna burn a
long time. Like there are stars that have lifetimes of
trillions of years, but that's not up us. So in
five billion years, we've got to figure something out. Yeah,
we have. We have to figure out how to find
get to another star. And we got less than you know,
three ish billion years to figure that out. Oh man,
so we have to jump to another star that that

(19:15):
is burning and or um just learn to live in
the dark kind of right, Well, you know, fusion is
not impossible. You know, we can copy the energy source
of the stars, um if if we we don't necessarily
necessarily need a star, right, we could power ourselves through
our own controlled fusion if we if we could figure
that out. But do we have enough hydrogen or water

(19:38):
to last as that long? Yeah? I mean the Sun
is massively inefficient, right, Like most of the energy the
Sun gets thrown off into space and then and not
even used. So we wouldn't need anything nearly as big
as the Sun to power human civilization. So we could
just go out there grab some of that hydrogen floating around,
or go to Jupiter maybe grab all that hydrogen, create
our little mini sun here. Yeah. Or you know, if

(20:01):
you're living out in space, you don't have to worry
about pollution, like, so you can just do fission, which
is much easier, and there's plenty of that stuff floating around,
and you know, you get radioactive waste, you're just jettison.
You're already in space, so who cares? Right, Interesting because
you used to think the ocean was too big and
you could just polluted forever without consequences. We know that's
not true, but it is true of the universe that
you're never going to fill the universe with garbage. Yeah,

(20:23):
you think in a billion years people gonna say, I
can't believe they filled space with junk. Man, you're responsible.
You're gonna be like, don't throw don't throw plastic bags
out into space because the space dolphins are gonna it
kills all those cute space and space dolphins choking on
your cosmic ways. Why is that funny, worry? I don't

(20:43):
think that's funny at all, and I think you're a
jerk for laughing. Cool. Well, that's that's kind of interesting,
that the idea that maybe we will never leave our
solar system and we will just figure out how to
make our own little minisans to keep us warm. Yeah. Absolutely,
I think I think we could do that. Until then,
I guess, um, we're sunscreen that's right, And don't worry

(21:07):
too much about the sun burning out. We have bigger
problems to figure out than whether the sun is going
to explode. You've got lots of time to work on
that problem. Do you have a question you wish we
would cover, Send it to us. We'd love to hear
from you. You can find us on Facebook, Twitter, and
Instagram at Daniel and Jorge One Word, or email us

(21:28):
to feedback at Daniel and Jorge dot com