July 22, 2017 • 27 mins
In this week's SYSK Select episode, amateur astrophysicists Josh and Chuck break out the stats and attempt to explain the complex, boiling ball of gas that we call the sun.
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Episode Transcript
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Speaker 1 (00:01):
Hey, everybody, this is Chuck bringing you this week's S
Y s K Select and we are going there. People. Well,
Josh actually doesn't even know I'm picking this one yet,
so he might be mad. But what you were about
to hear is the legendary How the Sun Works episode. Uh.
And if you haven't heard us talk about this over
the years, then you haven't listened to many episodes or
(00:24):
heard many interviews with us, because this one has gone
down and stuff you should know lore as uh, what
we call our worst episode ever because it was so
hard and we were so in over our heads and
we were clinging to the cliff side by our little
nubby fingers during the entire podcast and got a lot
(00:46):
of it wrong. And so, uh, instead of burying this thing,
I chose to highlight it this week. So, without further ado,
from January two thousand ten, are amazing episode How the
Sun Works. Enjoy m Welcome to Stuff you Should Know
(01:17):
from House Stuff Works dot com. Hey, and welcome to
the podcast. I am Josh Clark. That's Chuck Bryant. Charles
Charles W. Bryant is not very happy right now. I'm
gonna handle this, okay, Chuck the whole thing. This disclaimer. Okay,
(01:41):
as we prove with our large Hadron Collider podcast, Chuck
and I are not physicists. By the way, it doesn't
shoot light. No, we found out speaking of light, we're
about to talk about sun. Yes, And I just want
to say that Chuck and I are not astrophysicists either.
There's a couple of guys who like to drink some
beer and you know, just talk. Just wrap. I thought
(02:04):
I was an astrophysicist until I read the Sun article
and then my brain melted and newsed out of my ears.
You're an astrophysicist. You're way off, way off. So we're
going to talk about the sun. If we get any
of the um you know, theory, if we get the
theory of relativity, and actually no, we can't screw that
one up. It's too famous. If there's a little thing
(02:24):
here there and you're an astrophysicist, please feel free to
send it's an email correcting us. We love that. Um
that's the first time we've ever called for corrections before.
I think this one's appropriate. So let's let's let me start. Chuck,
have you ever heard of the sun? Yes, Josh, I
wish we had more of it these days here in
cold it is, it's a little chilly. If you'll notice
(02:47):
it's snowed here, Chuck. I feel notice though, after a
couple of days of sunlight the snow receded. Yes, do
you know why? Uh? No, radiation Okay, heat, yes, yeah,
energy from the sun. Right. The Sun, which, Josh, is
one of over one hundred billion stars. It's just a
(03:08):
star it is, and not even like a giant star either.
It falls a little above average size. Did you know that?
Should we talk about the size? Yeah? Because if there's
one thing I can do is read stats. Yeah, this was.
This is a very stat heavy article, so it should
be up your alley, Josh. The Sun's radius is about
four hundred and thirty two thousand miles. Yeah, it's a
(03:29):
hundred nine times the radius of the Earth. Yes, one
on nine exactly, which I was like, Wow, that means
that it has a two hundred and eighteen times a diameter.
No that's not true. Still one on nine. It's constant. Uh,
And I like this. NASA. NASA broke it down, our
good friends at NASA into something that I understood, which was,
if you think of the Earth, um the width of
(03:52):
an ordinary paper clip is the Earth's radius. Let's say,
then the Sun's radius would be roughly the height of
a desk. And I know this one about one hundred
steps from each other. Is that what you're gonna say
it was? That's all right? Hey? So yeah, that kind
of puts it in a perspective. The Sun's a hell
of a lot bigger than the Earth, much much bigger,
and it's pretty far away, right, how many miles did
(04:13):
you say? Eight light minutes? Which is actually, chuck, apparently
ninety two million miles and change. And to put that
into perspective, other stars are light years away, not eight
light minutes away. And since this is a stat bonanza,
can I take a shot at one? So you said
that the uh, the Sun was how many light years?
(04:35):
Twenty five thousand light years from the center of the galaxy. Yes,
it takes about two hundred and fifty million years for
the Sun to uh do one revolution around the galaxy?
Can we stop here? I feel really good about it
so far. Yeah, I'm feeling pretty good. To check. Let's
soldier on, shall we Yes, the Sun is a G
two type star based on its temperature and the wavelengths
(04:58):
of light that it minutes, right, and it's about four
and a half billion years old, uh, which makes it
a population one star. Apparently there are two types of
stars as far as age classification goes. I didn't know
that population one star are the younger stars, which include
our sun. Population two stars are older, and they think
that there was a third population, but none of them
(05:19):
are around anymore. Population three. Right, they should just go
ahead and just claim that why not exactly, We wouldn't know.
We'd be like, oh, nobody would ever know. Right. Well,
luckily NASA is very honest and forth right. Thank thank you, NASA,
Thank you. So yeah, check the Sun we said, is
about four and a half billion years old um, and
they think it's about humanity arrived at about the halfway
(05:41):
point in the Sun's lifetime. It's got about five billion
more years worth of UM fuel, which is good news,
it is, because yeah, at the end of that run,
it's not good news for us. No, we'll get to that.
That'll be the grand finale. How about that? Exactly? All right? So, Chuck,
what is the Sun? What should we talk about the
parts of the Sun or I just want to talk
(06:02):
about the fact that it's a big you know, ball
of gas. I think we should mention that because if you,
if you talk about what the Sun is, I think
it's easier to understand it's different components and then in
turn what it is. Okay, well, it's made up entirely
of gas josh, which is really weird because gas generally
doesn't form a ball and have an atmosphere and all
(06:24):
that stuff. I know why though, why because of the
extreme gravity. Yeah, and heat and heat right holds everything together, right,
which is crazy. So this extreme this extreme heat actually
uh takes this gas and converts it into what is
technically a fourth state of matter. You've got solid liquid
gas and plasma. Plasma, and plasma is a type of
(06:46):
gas um that behaves in a way where it's um
it responds to magnetism. Right. Generally people just say that
it's gas, but unless you want to get really technical,
and you'll call it plasma. Yeah, that's what nassas it is. Like.
Scientists only sometimes will even call it plasma. Right. So,
the core, which we'll talk about in just a second.
(07:07):
But the core is so dense thanks to the force
of gravity that um it makes up two of the
Sun's volume, but it counts for half of the density
of the entire Sun. Right, and so the the gravitational
field in the core is so strong that it pulls
hydrogen atoms together in a nuclear reaction, a fusion reaction,
(07:31):
which is where everything begins. Yes, this is what everything
is accounted for for the Sun, right. Yeah. And a
fusion reaction, just if you guys don't know, is when
two atomic nuclei joined together and create a new nucleus.
And so the key um, the key element, I guess,
uh in the Sun's nuclear reactions, because that's all it is.
(07:53):
It's not it's not burning like we consider like a
wood fire to be burning. It's burning like a It's
a huge nuclear reaction basic the sunnets right, um. But
the key element is a helium four. When helium four
is created, um, the it has actually less mass than
the two I think hydrogen atoms that originally began that
(08:15):
set off this chain reaction that led to the creation
of helium four. And since matter or energy can either
be created nor destroyed, it has to be displaced. Right.
So under Einstein's theory relativity, which we won't screw up here,
energy equals mass times of speed of light squared. You
can describe how much energy is created. Right, So when
(08:36):
the mass is displaced, when the helium four atom is created, right,
the mass is this placed, it's created, it transfers into energy. Right.
I'm wondering how many of our commuters right now switch
this off and just put on Howard Stern, Like my
fingernails are bleeding. I'm hanging on just barely right now, thanks, buddy.
(08:58):
So are you all right? So Chuck, that's the core,
(09:29):
that's the center of the sun. Yes, it extends to
of the Sun's radius, just so you know how big
that is. And it's hot, hot, hot kelvin, which is
really hot. Trust u um. And uh, that's at the center,
like you said, it's the radius. What's outside of that?
Just outside of that is the radiative zone. Is how
(09:52):
you pronounce that one? Either that or radiative radiative radiative
that extends about of the Sun's radius from the core, right, Okay,
So uh, these helium four atoms are created, and remember
they create energy or they displace energy. Right when they
lose their mass translation energy, that energy starts traveling outward
(10:16):
and it hits the radiative zone, and they are they're
generally um. The type of energy that's created can be
gamma rays, X rays, whatever, But technically all of these
are um light waves. So they're carried in these discrete
little packets called photons, right, Yes, they're carried by the photons.
And uh, the photon travels only about one micron, which
(10:39):
is a millionth of a meter, before it's absorbed by
a gas molecule. Right. Okay, So then this photon which
is absorbed by the gas molecule, heats the gas molecule up,
and then the photon or the gas molecule spits out
another photon, which is technically the same one because it's
the same wavelength as the original photon, right, and then
it shows another micro until it's absorbed by another gas molecule. Right.
(11:03):
So this keeps going on and on and on, and
by the time the photon escapes from the radiative zone, uh,
averages about a million years from the time it was
I guess created. You could say from the creation of
that helium four adam a million years for one photon
of light to travel this uh this short distance. Yeah,
(11:26):
that would be ten to the twenty five absorption and
re emissions taking place. Yeah, that's a lot. That's a
lot of zeroes. Yeah, um, it's actually uh, I think
exactly maybe twenty six. So once it escapes the radiative zone,
it hits the convective zone right right, and that is
the final thirty percent of the Sun's radius basically, right. Uh.
(11:49):
It takes a little while for that same photon to
escape that area, right, A hundred thousand to two hundred
thousand years to reach the surface of the Sun. Yes,
what's crazy is this. Once it escapes, Once that one
photon escapes services Sun, it takes eight minutes to reach
the Earth's surface because remember where it's light minutes away,
and its light travels at the speed of light, so
(12:11):
it takes eight minutes. But the sunlight that's hitting us
when we go outside are made up of photons that
were created more than one point two million years ago.
I can't even comprehend that. Awesome. That is really really cool.
So we've got all these ancient photons bouncing office. But
let's get back to the convective zone, right, Okay, this
is uh, this is this area made up of these
(12:33):
alternating areas of rising and cooling gas. Right as NASA
once again breaks it down, a little easier. It's boiling
convection cells basically, right, it looks like a pot of
boiling water, except these are gas plasma. No, there's only
the Sun. Only the Sun. Okay, chuck. So we have
the three parts of the Sun. We have the core,
(12:53):
the radiative zone, and the convective zone. Right, and now
we've reached the atmosphere. The Sun actually has an atmosphere.
Yes it does, Yes, it does. And that's made up
of three parts as well, right, correct, the photosphere, the chromosphere,
and my favorite, I think everyone's favorite, the corona. I
like the corona, which can only be seen in an eclipse. Yeah,
corona gets all the press, it does, so, Joshua. In
(13:15):
the photosphere we are is that where we are it
is hot. That is the lowest region in the atmosphere,
or Sun's atmosphere, and that is the region that you
can actually see from Earth. That's where you can start
to see things. Right. And actually the photosphere is what
gives the Sun. It's kind of round crisp edge because
as as um as you travel outward to the outside
(13:37):
of the photosphere, the gas is cooler, which creates that
crisp edge we see for the Sun right, has an
average temp of about fifty eight hundred kelvin, and it
is two hundred and forty miles wide. Right, that's big.
It is big. After that is the chromosphere, right, Yes,
that's outside the photosphere. Obviously, it's about my els above
(14:01):
the photosphere, right, and that's about degrease kelvin. So obviously
you'll notice that it's getting cooler, you know, as you
expand outward, right, but it's still they think it's heated
by the photosphere and this this churning gas, the convection
cells are still present in the chromosphere as well. So
basically the what what we're seeing so far is the
(14:22):
Sun is this nuclear reactor that at its core, gravity
is pushing things together and then they're exploding outward. Right. Okay, Okay,
I'm with you, But actually I I sort of mispoke
because it actually the temperature does rise across the chromosphere,
and it can rise up to ten thousand kelvin, which
is even hotter than the photosphere beneath it. Uh. And
(14:44):
then we have the corona chuck your favorite. Yeah, that's
the final layer, Josh, and it extends several million miles
outward from the photosphere and you can see this. In fact,
I think they first discovered the corona during the first
solar eclipse. They were like, what the hell is that? Exactly?
How hot does that one? Josh? It's a two billion
degrees kelvin actually, which again it's very hot. Yeah, so
(15:06):
it's not actually cooling as it goes out. Word, I
completely misspoke. No, it's it's that's the I think that's
one of the reasons why the Sun has these different
features like sun spots and solar prominences, which we're about
to talk about, is because these um cooling and heating
raising and rising and lowering convection cells are kind of
competing with one another, and they actually create the magnetism
(15:30):
that UM the plasma is attracted to or responds to,
I should say, right, And I don't feel too bad
because the article even says that no one knows why
the corona is so hot. No, because you would think
it would be cooler. But and there are hotter places
than others because the cooler spots are called coronal holes. Uh,
they're also let's talk about sun spots, chuck, Okay, sun
(15:51):
spots are UM these areas of magnetic activity along the photosphere, right,
darker and cooler. Right. Um, they always appear in pairs
as far as I know, although I think they can
appear singularly, but it's very uncommon because it's a monopole. Right.
Like I said that, there's that um that convection activity
that actually creates the magnetic fields around the sun, right right,
(16:14):
And so when sun spots appear, generally they appear in
in pairs because one represents magnetic north and the other
represents magnetic south. And along these magnetic fields, other solar
activity can occur. Right, You've got solar prominences, which is
actually an arc of uh. I think particles and radiation
that can extend, uh, I think a thousand kilometers outside
(16:37):
of the Sun's atmosphere. Right, Yeah, they can, and they
last for two or three months. It's like a temporary thing, right.
And these things are it's kind of like um, an
arc of electricity, except a lot bigger, right right. Uh.
And every once in a while they erupt into coronal
mass ejections, right, which is my next band name? Is it?
(16:58):
Coronal mass ejection? That's give? Uh? Can we? I got
one more thing on sun spots, which I thought was
really cool is you know, they break through their magnetic
fields that breakthrough the surface, but they can only enter, exit,
and re enter through other sun spots, which I thought
was pretty cool. That is pretty cool. They also occur
on eleven year cycles, right, yes, the solar cycle a
(17:19):
full cycle, a full solar cycles twenty two years, so
every eleven years that either peaks or troughs. And what's
interesting is, um, you know, everybody's like the world's gonna
and I think we mentioned this in our twenty twelve podcast.
That is the predicted peak of the solar cycle maximum
that we're in. So you've got these sun spots, the
(17:43):
sun spot activity is gonna pick up. When sun spots
pick up, Solar prominences pick up. When there's more solar prominences,
there's more coronal mass ejections. When there's more coronal mass ejections,
the Earth is inundated with um uh radiation and radioactive articles. Right,
they hit the Earth's atmosphere and actually mess with the
(18:04):
magnetic field. This accounts for the Aurora borealis and Australia's right, right,
and um When enough of them hit the Earth's atmosphere
and they actually ionize, they interfere with our electrical activity, right,
calls like blackouts, right, which is why a lot of
people think that will have all these catastrophes. Right, that
makes sense, But really it's just part of a twenty
(18:26):
two year cycle of the sun. So calm down, are
your minds exactly know? The mines don't think that? That's right? Josh? Yes,
you want to talk about the color of the sun
real quick. Yeah, because this is a cool little fact
that I bet most people don't know, because most people
say the sun is yellow or orange. Not true. The
sun is actually white. Sunlight is actually white. Do you
(18:47):
know why it changes the atmosphere? Oh? Yeah, The atmosphere
acts as a filter for the setting sun and that's
when it changes its color. Well, and it is white.
It does appear white, but it's actually made up of
all the colors of the spectrum, which is why you
can take a prism and um shoot sunlight through it
and it spreads into the different colors and you have
(19:08):
pink Floyd's Dark Side of the Moon album cover. Right.
I got another couple of cool facts. Rotation of the sun.
Everyone knows it makes a complete rotation in about a month.
But because it's a gas. Basically, it's different parts rotate
at different rates. So gas near the equator takes twenty
five days to rotate, let's say, and gas at higher
latitudes may take as many as like three more extra days. Right,
(19:31):
pretty cool. So it's rotating at different rates. It is
because it's a ball of gas, exactly. And I got
one more You ready for this one about the vibration. Yeah,
this is pretty cool too. I thought I had no idea.
The sun vibrates constantly like a bell that is continuously struck, right,
creating sound ways. But there's two minutes between intervals, yes,
(19:52):
and ten million individual tones at the same time, So
we we could if our hearing was I guess different.
I don't know if better is the right word, but
if we had a different type of hearing, we would
be able to hear the vibrations coming off of the
Sun because actually do hit the Earth. But like I said,
in two minute intervals the slowest distance between intervals time
(20:15):
wise that humans can hear a second. So it's it's
constantly making a sound, we just can't hear. It just
leads me to the question, if the sun makes a
sound while it's vibrating, can you hear it. I bet
those blue people in Avatar can hear it. Now, you
still haven't seen it. I'll never see that movie. You
(20:37):
should never. You're gonna be that guy. Yeah, okay, that's fine.
(21:12):
I got a couple of other stats for you, Josh,
if you're into it. Well, not a fewer than five
percent of the stars in the Milky Way are brighter
or more massive than the Sun, but some are more
than one hundred thousand times is bright. Isn't that crazy? Yes,
that is pretty cool actually, And if you go in
the other way, some stars are less than one ten
as bright as the Sun, which is kind of nuts.
(21:33):
But really, I mean stat wise that we have a
fairly mediocre sun. Yeah, it does the trick, though, Yes,
it does s the trick, and it should for about
the next five billion years. Like we said, they or
the Sun is middle aged right now, right, it's about
halfway through. Sure, it's starting to look into wearing treck
suits all the time out in public exactly. Um, and uh,
after about five billion years, it's going to run out
(21:57):
of fuel, Yeah, run out of hydrogen. And what happens then, Well,
that density of the core is going to remain, but
it's not going to have the fuel to create these
um nuclear reactions, which remember we said that the Sun
is a bunch of nuclear reactions. This gravity smashing things
together and then the energy escaping. It's this constant pushing pull. Well,
(22:19):
when it runs out of fuel, there's gonna be nothing
but pull. There won't be any push any longer, right right,
which is bad news for the core. Right. But before
this happens, when this, when this kicks off, Chuck, it's
going to turn into a red giant. And this red
giant is you know how the Sun just kind of
heats the earth. Yes, well that's not gonna happen. I mean,
it'll heat the earth, but it's also going to vaporize
(22:41):
it when it turns into a red giant, which is
the bad news for us. Well, we probably won't be around.
We'll be long gone. There'll be no trace of humanity
anywhere in five billion years. In no way I would
think not. I don't know that we have that much
staying power. Um. And so the Sun is going to
vaporize the Earth, which is probably pretty wicked cool this.
See when that does happen, Um, after that, the core
(23:04):
will be Then the core will turn into carbon. I
must spoke earlier, right right, which is cools cools it down, right,
and then as it cools, it will turn into a
white dwarf, and then a black dwarf eventually, Yes, and
then it'll just be some hulk that won't even resemble
our sun anymore. Right, And once this whole process starts,
it's gonna take uh several billion years to even complete
(23:27):
that process. So now it happens overnight or a probably
about ten billion years from now, the Sun will just
be this massive hulk of carbon, right, like my brain
is right now. Not so massive that can we be
done now? I think? So? Okay, I mean there's a
lot more. We didn't even touch on solar wind and
things like that, but we leave it up to the
(23:47):
listener to pursue these. Yeah, sure, the listener or stuff
from the Science Lab or soon to be forthcoming sister
podcast with the esteemed Robert Lamb and his esteemed editor
Alison louder Milk, And then we can just talk about noodling. Yeah,
we'll go back to what we do best. It's just
(24:08):
bumpkin stuff, So Chuck, Josh, I can barely get it out,
I know. The listener, May I feel so defeated. I'm
just gonna call this the best part of this podcast.
Uh this is on human Experimentation, and we actually, as always,
(24:29):
if we put out a call for some random weirdness,
there's someone out there that listens to the show that
has been there and done that. Remember the kid whose
father used him as a human shield. Why? Uh So
I've got this one from Rebecca and she says this.
I just listened to the podcast on Human Experimentation. It
was thrilled that you featured something I can relate to
because I'm a former NASA human test subject. We just
(24:53):
talked about NASA. I know, weird funny how that works.
In two thousand six, I spent three months in a
bed at a negative six degree tilt. Isn't that crazy?
The effects of the human body at that angle are
very similar to what an astronaut goes through after spending
extended periods of time and space, which makes me wonder
how they figure that out? You know, because they're NASA,
(25:13):
that's the answer. Eventually, NASA hopes to take that information
they got from my time in bed to help astronauts
stay in space longer and travel further. From the Earth
and one day even land on Mars. As a test subject,
everything I did, from surfing the internet, eating, reading, even
using the bathroom was at an angle tilt. Five days
(25:34):
a week, I was wheeled to a lab where I
was attached to an elaborate pulley system that pulled me
onto a treadmill. What that was bolted to the wall.
I walked, jog and ran a few miles a day
to help my body avoid muscle atrophy. Of course, uh not.
Everyone selected for the study was so lucky, though half
of them did not get to run in this on
this unique contraption, so they were just in bed the
whole time. The date of the engineers got from my
(25:57):
running will help NASA figure out what types of exercise
astronauts will have to do to uh experience like long
extended trips into space. So while I didn't love everything
about it, going to the restroom, for example, it is
a thrilling thing to have been a part of. I'm
a huge fan and I'd like to learn neat stuff. Rebecca,
did you have that last part? No? No No, no, she
(26:17):
said that, Okay, yeah, more neat stuff. Well, thanks, Rebecca,
hats off to you for helping our astronauts. She didn't
mention if how much she got paid, if at all,
but I mean, and she did NASA's deep pockets, buddy,
that's what I hear. Yeah. Well, if you have any
stories about developing bed sores for the greater good of
advancing human knowledge, you can send in an email to
(26:38):
stuff Podcasts at how stuff works dot com. For more
on this and thousands of other topics, is that how
stuff works dot com. Want more how stuff works, check
out our blogs on the house stuff works dot com
home page
Hey, everybody, this is Chuck bringing you this week's S
Y s K Select and we are going there. People. Well,
Josh actually doesn't even know I'm picking this one yet,
so he might be mad. But what you were about
to hear is the legendary How the Sun Works episode. Uh.
And if you haven't heard us talk about this over
the years, then you haven't listened to many episodes or
(00:24):
heard many interviews with us, because this one has gone
down and stuff you should know lore as uh, what
we call our worst episode ever because it was so
hard and we were so in over our heads and
we were clinging to the cliff side by our little
nubby fingers during the entire podcast and got a lot
(00:46):
of it wrong. And so, uh, instead of burying this thing,
I chose to highlight it this week. So, without further ado,
from January two thousand ten, are amazing episode How the
Sun Works. Enjoy m Welcome to Stuff you Should Know
(01:17):
from House Stuff Works dot com. Hey, and welcome to
the podcast. I am Josh Clark. That's Chuck Bryant. Charles
Charles W. Bryant is not very happy right now. I'm
gonna handle this, okay, Chuck the whole thing. This disclaimer. Okay,
(01:41):
as we prove with our large Hadron Collider podcast, Chuck
and I are not physicists. By the way, it doesn't
shoot light. No, we found out speaking of light, we're
about to talk about sun. Yes, And I just want
to say that Chuck and I are not astrophysicists either.
There's a couple of guys who like to drink some
beer and you know, just talk. Just wrap. I thought
(02:04):
I was an astrophysicist until I read the Sun article
and then my brain melted and newsed out of my ears.
You're an astrophysicist. You're way off, way off. So we're
going to talk about the sun. If we get any
of the um you know, theory, if we get the
theory of relativity, and actually no, we can't screw that
one up. It's too famous. If there's a little thing
(02:24):
here there and you're an astrophysicist, please feel free to
send it's an email correcting us. We love that. Um
that's the first time we've ever called for corrections before.
I think this one's appropriate. So let's let's let me start. Chuck,
have you ever heard of the sun? Yes, Josh, I
wish we had more of it these days here in
cold it is, it's a little chilly. If you'll notice
(02:47):
it's snowed here, Chuck. I feel notice though, after a
couple of days of sunlight the snow receded. Yes, do
you know why? Uh? No, radiation Okay, heat, yes, yeah,
energy from the sun. Right. The Sun, which, Josh, is
one of over one hundred billion stars. It's just a
(03:08):
star it is, and not even like a giant star either.
It falls a little above average size. Did you know that?
Should we talk about the size? Yeah? Because if there's
one thing I can do is read stats. Yeah, this was.
This is a very stat heavy article, so it should
be up your alley, Josh. The Sun's radius is about
four hundred and thirty two thousand miles. Yeah, it's a
(03:29):
hundred nine times the radius of the Earth. Yes, one
on nine exactly, which I was like, Wow, that means
that it has a two hundred and eighteen times a diameter.
No that's not true. Still one on nine. It's constant. Uh,
And I like this. NASA. NASA broke it down, our
good friends at NASA into something that I understood, which was,
if you think of the Earth, um the width of
(03:52):
an ordinary paper clip is the Earth's radius. Let's say,
then the Sun's radius would be roughly the height of
a desk. And I know this one about one hundred
steps from each other. Is that what you're gonna say
it was? That's all right? Hey? So yeah, that kind
of puts it in a perspective. The Sun's a hell
of a lot bigger than the Earth, much much bigger,
and it's pretty far away, right, how many miles did
(04:13):
you say? Eight light minutes? Which is actually, chuck, apparently
ninety two million miles and change. And to put that
into perspective, other stars are light years away, not eight
light minutes away. And since this is a stat bonanza,
can I take a shot at one? So you said
that the uh, the Sun was how many light years?
(04:35):
Twenty five thousand light years from the center of the galaxy. Yes,
it takes about two hundred and fifty million years for
the Sun to uh do one revolution around the galaxy?
Can we stop here? I feel really good about it
so far. Yeah, I'm feeling pretty good. To check. Let's
soldier on, shall we Yes, the Sun is a G
two type star based on its temperature and the wavelengths
(04:58):
of light that it minutes, right, and it's about four
and a half billion years old, uh, which makes it
a population one star. Apparently there are two types of
stars as far as age classification goes. I didn't know
that population one star are the younger stars, which include
our sun. Population two stars are older, and they think
that there was a third population, but none of them
(05:19):
are around anymore. Population three. Right, they should just go
ahead and just claim that why not exactly, We wouldn't know.
We'd be like, oh, nobody would ever know. Right. Well,
luckily NASA is very honest and forth right. Thank thank you, NASA,
Thank you. So yeah, check the Sun we said, is
about four and a half billion years old um, and
they think it's about humanity arrived at about the halfway
(05:41):
point in the Sun's lifetime. It's got about five billion
more years worth of UM fuel, which is good news,
it is, because yeah, at the end of that run,
it's not good news for us. No, we'll get to that.
That'll be the grand finale. How about that? Exactly? All right? So, Chuck,
what is the Sun? What should we talk about the
parts of the Sun or I just want to talk
(06:02):
about the fact that it's a big you know, ball
of gas. I think we should mention that because if you,
if you talk about what the Sun is, I think
it's easier to understand it's different components and then in
turn what it is. Okay, well, it's made up entirely
of gas josh, which is really weird because gas generally
doesn't form a ball and have an atmosphere and all
(06:24):
that stuff. I know why though, why because of the
extreme gravity. Yeah, and heat and heat right holds everything together, right,
which is crazy. So this extreme this extreme heat actually
uh takes this gas and converts it into what is
technically a fourth state of matter. You've got solid liquid
gas and plasma. Plasma, and plasma is a type of
(06:46):
gas um that behaves in a way where it's um
it responds to magnetism. Right. Generally people just say that
it's gas, but unless you want to get really technical,
and you'll call it plasma. Yeah, that's what nassas it is. Like.
Scientists only sometimes will even call it plasma. Right. So,
the core, which we'll talk about in just a second.
(07:07):
But the core is so dense thanks to the force
of gravity that um it makes up two of the
Sun's volume, but it counts for half of the density
of the entire Sun. Right, and so the the gravitational
field in the core is so strong that it pulls
hydrogen atoms together in a nuclear reaction, a fusion reaction,
(07:31):
which is where everything begins. Yes, this is what everything
is accounted for for the Sun, right. Yeah. And a
fusion reaction, just if you guys don't know, is when
two atomic nuclei joined together and create a new nucleus.
And so the key um, the key element, I guess,
uh in the Sun's nuclear reactions, because that's all it is.
(07:53):
It's not it's not burning like we consider like a
wood fire to be burning. It's burning like a It's
a huge nuclear reaction basic the sunnets right, um. But
the key element is a helium four. When helium four
is created, um, the it has actually less mass than
the two I think hydrogen atoms that originally began that
(08:15):
set off this chain reaction that led to the creation
of helium four. And since matter or energy can either
be created nor destroyed, it has to be displaced. Right.
So under Einstein's theory relativity, which we won't screw up here,
energy equals mass times of speed of light squared. You
can describe how much energy is created. Right, So when
(08:36):
the mass is displaced, when the helium four atom is created, right,
the mass is this placed, it's created, it transfers into energy. Right.
I'm wondering how many of our commuters right now switch
this off and just put on Howard Stern, Like my
fingernails are bleeding. I'm hanging on just barely right now, thanks, buddy.
(08:58):
So are you all right? So Chuck, that's the core,
(09:29):
that's the center of the sun. Yes, it extends to
of the Sun's radius, just so you know how big
that is. And it's hot, hot, hot kelvin, which is
really hot. Trust u um. And uh, that's at the center,
like you said, it's the radius. What's outside of that?
Just outside of that is the radiative zone. Is how
(09:52):
you pronounce that one? Either that or radiative radiative radiative
that extends about of the Sun's radius from the core, right, Okay,
So uh, these helium four atoms are created, and remember
they create energy or they displace energy. Right when they
lose their mass translation energy, that energy starts traveling outward
(10:16):
and it hits the radiative zone, and they are they're
generally um. The type of energy that's created can be
gamma rays, X rays, whatever, But technically all of these
are um light waves. So they're carried in these discrete
little packets called photons, right, Yes, they're carried by the photons.
And uh, the photon travels only about one micron, which
(10:39):
is a millionth of a meter, before it's absorbed by
a gas molecule. Right. Okay, So then this photon which
is absorbed by the gas molecule, heats the gas molecule up,
and then the photon or the gas molecule spits out
another photon, which is technically the same one because it's
the same wavelength as the original photon, right, and then
it shows another micro until it's absorbed by another gas molecule. Right.
(11:03):
So this keeps going on and on and on, and
by the time the photon escapes from the radiative zone, uh,
averages about a million years from the time it was
I guess created. You could say from the creation of
that helium four adam a million years for one photon
of light to travel this uh this short distance. Yeah,
(11:26):
that would be ten to the twenty five absorption and
re emissions taking place. Yeah, that's a lot. That's a
lot of zeroes. Yeah, um, it's actually uh, I think
exactly maybe twenty six. So once it escapes the radiative zone,
it hits the convective zone right right, and that is
the final thirty percent of the Sun's radius basically, right. Uh.
(11:49):
It takes a little while for that same photon to
escape that area, right, A hundred thousand to two hundred
thousand years to reach the surface of the Sun. Yes,
what's crazy is this. Once it escapes, Once that one
photon escapes services Sun, it takes eight minutes to reach
the Earth's surface because remember where it's light minutes away,
and its light travels at the speed of light, so
(12:11):
it takes eight minutes. But the sunlight that's hitting us
when we go outside are made up of photons that
were created more than one point two million years ago.
I can't even comprehend that. Awesome. That is really really cool.
So we've got all these ancient photons bouncing office. But
let's get back to the convective zone, right, Okay, this
is uh, this is this area made up of these
(12:33):
alternating areas of rising and cooling gas. Right as NASA
once again breaks it down, a little easier. It's boiling
convection cells basically, right, it looks like a pot of
boiling water, except these are gas plasma. No, there's only
the Sun. Only the Sun. Okay, chuck. So we have
the three parts of the Sun. We have the core,
(12:53):
the radiative zone, and the convective zone. Right, and now
we've reached the atmosphere. The Sun actually has an atmosphere.
Yes it does, Yes, it does. And that's made up
of three parts as well, right, correct, the photosphere, the chromosphere,
and my favorite, I think everyone's favorite, the corona. I
like the corona, which can only be seen in an eclipse. Yeah,
corona gets all the press, it does, so, Joshua. In
(13:15):
the photosphere we are is that where we are it
is hot. That is the lowest region in the atmosphere,
or Sun's atmosphere, and that is the region that you
can actually see from Earth. That's where you can start
to see things. Right. And actually the photosphere is what
gives the Sun. It's kind of round crisp edge because
as as um as you travel outward to the outside
(13:37):
of the photosphere, the gas is cooler, which creates that
crisp edge we see for the Sun right, has an
average temp of about fifty eight hundred kelvin, and it
is two hundred and forty miles wide. Right, that's big.
It is big. After that is the chromosphere, right, Yes,
that's outside the photosphere. Obviously, it's about my els above
(14:01):
the photosphere, right, and that's about degrease kelvin. So obviously
you'll notice that it's getting cooler, you know, as you
expand outward, right, but it's still they think it's heated
by the photosphere and this this churning gas, the convection
cells are still present in the chromosphere as well. So
basically the what what we're seeing so far is the
(14:22):
Sun is this nuclear reactor that at its core, gravity
is pushing things together and then they're exploding outward. Right. Okay, Okay,
I'm with you, But actually I I sort of mispoke
because it actually the temperature does rise across the chromosphere,
and it can rise up to ten thousand kelvin, which
is even hotter than the photosphere beneath it. Uh. And
(14:44):
then we have the corona chuck your favorite. Yeah, that's
the final layer, Josh, and it extends several million miles
outward from the photosphere and you can see this. In fact,
I think they first discovered the corona during the first
solar eclipse. They were like, what the hell is that? Exactly?
How hot does that one? Josh? It's a two billion
degrees kelvin actually, which again it's very hot. Yeah, so
(15:06):
it's not actually cooling as it goes out. Word, I
completely misspoke. No, it's it's that's the I think that's
one of the reasons why the Sun has these different
features like sun spots and solar prominences, which we're about
to talk about, is because these um cooling and heating
raising and rising and lowering convection cells are kind of
competing with one another, and they actually create the magnetism
(15:30):
that UM the plasma is attracted to or responds to,
I should say, right, And I don't feel too bad
because the article even says that no one knows why
the corona is so hot. No, because you would think
it would be cooler. But and there are hotter places
than others because the cooler spots are called coronal holes. Uh,
they're also let's talk about sun spots, chuck, Okay, sun
(15:51):
spots are UM these areas of magnetic activity along the photosphere, right,
darker and cooler. Right. Um, they always appear in pairs
as far as I know, although I think they can
appear singularly, but it's very uncommon because it's a monopole. Right.
Like I said that, there's that um that convection activity
that actually creates the magnetic fields around the sun, right right,
(16:14):
And so when sun spots appear, generally they appear in
in pairs because one represents magnetic north and the other
represents magnetic south. And along these magnetic fields, other solar
activity can occur. Right, You've got solar prominences, which is
actually an arc of uh. I think particles and radiation
that can extend, uh, I think a thousand kilometers outside
(16:37):
of the Sun's atmosphere. Right, Yeah, they can, and they
last for two or three months. It's like a temporary thing, right.
And these things are it's kind of like um, an
arc of electricity, except a lot bigger, right right. Uh.
And every once in a while they erupt into coronal
mass ejections, right, which is my next band name? Is it?
(16:58):
Coronal mass ejection? That's give? Uh? Can we? I got
one more thing on sun spots, which I thought was
really cool is you know, they break through their magnetic
fields that breakthrough the surface, but they can only enter, exit,
and re enter through other sun spots, which I thought
was pretty cool. That is pretty cool. They also occur
on eleven year cycles, right, yes, the solar cycle a
(17:19):
full cycle, a full solar cycles twenty two years, so
every eleven years that either peaks or troughs. And what's
interesting is, um, you know, everybody's like the world's gonna
and I think we mentioned this in our twenty twelve podcast.
That is the predicted peak of the solar cycle maximum
that we're in. So you've got these sun spots, the
(17:43):
sun spot activity is gonna pick up. When sun spots
pick up, Solar prominences pick up. When there's more solar prominences,
there's more coronal mass ejections. When there's more coronal mass ejections,
the Earth is inundated with um uh radiation and radioactive articles. Right,
they hit the Earth's atmosphere and actually mess with the
(18:04):
magnetic field. This accounts for the Aurora borealis and Australia's right, right,
and um When enough of them hit the Earth's atmosphere
and they actually ionize, they interfere with our electrical activity, right,
calls like blackouts, right, which is why a lot of
people think that will have all these catastrophes. Right, that
makes sense, But really it's just part of a twenty
(18:26):
two year cycle of the sun. So calm down, are
your minds exactly know? The mines don't think that? That's right? Josh? Yes,
you want to talk about the color of the sun
real quick. Yeah, because this is a cool little fact
that I bet most people don't know, because most people
say the sun is yellow or orange. Not true. The
sun is actually white. Sunlight is actually white. Do you
(18:47):
know why it changes the atmosphere? Oh? Yeah, The atmosphere
acts as a filter for the setting sun and that's
when it changes its color. Well, and it is white.
It does appear white, but it's actually made up of
all the colors of the spectrum, which is why you
can take a prism and um shoot sunlight through it
and it spreads into the different colors and you have
(19:08):
pink Floyd's Dark Side of the Moon album cover. Right.
I got another couple of cool facts. Rotation of the sun.
Everyone knows it makes a complete rotation in about a month.
But because it's a gas. Basically, it's different parts rotate
at different rates. So gas near the equator takes twenty
five days to rotate, let's say, and gas at higher
latitudes may take as many as like three more extra days. Right,
(19:31):
pretty cool. So it's rotating at different rates. It is
because it's a ball of gas, exactly. And I got
one more You ready for this one about the vibration. Yeah,
this is pretty cool too. I thought I had no idea.
The sun vibrates constantly like a bell that is continuously struck, right,
creating sound ways. But there's two minutes between intervals, yes,
(19:52):
and ten million individual tones at the same time, So
we we could if our hearing was I guess different.
I don't know if better is the right word, but
if we had a different type of hearing, we would
be able to hear the vibrations coming off of the
Sun because actually do hit the Earth. But like I said,
in two minute intervals the slowest distance between intervals time
(20:15):
wise that humans can hear a second. So it's it's
constantly making a sound, we just can't hear. It just
leads me to the question, if the sun makes a
sound while it's vibrating, can you hear it. I bet
those blue people in Avatar can hear it. Now, you
still haven't seen it. I'll never see that movie. You
(20:37):
should never. You're gonna be that guy. Yeah, okay, that's fine.
(21:12):
I got a couple of other stats for you, Josh,
if you're into it. Well, not a fewer than five
percent of the stars in the Milky Way are brighter
or more massive than the Sun, but some are more
than one hundred thousand times is bright. Isn't that crazy? Yes,
that is pretty cool actually, And if you go in
the other way, some stars are less than one ten
as bright as the Sun, which is kind of nuts.
(21:33):
But really, I mean stat wise that we have a
fairly mediocre sun. Yeah, it does the trick, though, Yes,
it does s the trick, and it should for about
the next five billion years. Like we said, they or
the Sun is middle aged right now, right, it's about
halfway through. Sure, it's starting to look into wearing treck
suits all the time out in public exactly. Um, and uh,
after about five billion years, it's going to run out
(21:57):
of fuel, Yeah, run out of hydrogen. And what happens then, Well,
that density of the core is going to remain, but
it's not going to have the fuel to create these
um nuclear reactions, which remember we said that the Sun
is a bunch of nuclear reactions. This gravity smashing things
together and then the energy escaping. It's this constant pushing pull. Well,
(22:19):
when it runs out of fuel, there's gonna be nothing
but pull. There won't be any push any longer, right right,
which is bad news for the core. Right. But before
this happens, when this, when this kicks off, Chuck, it's
going to turn into a red giant. And this red
giant is you know how the Sun just kind of
heats the earth. Yes, well that's not gonna happen. I mean,
it'll heat the earth, but it's also going to vaporize
(22:41):
it when it turns into a red giant, which is
the bad news for us. Well, we probably won't be around.
We'll be long gone. There'll be no trace of humanity
anywhere in five billion years. In no way I would
think not. I don't know that we have that much
staying power. Um. And so the Sun is going to
vaporize the Earth, which is probably pretty wicked cool this.
See when that does happen, Um, after that, the core
(23:04):
will be Then the core will turn into carbon. I
must spoke earlier, right right, which is cools cools it down, right,
and then as it cools, it will turn into a
white dwarf, and then a black dwarf eventually, Yes, and
then it'll just be some hulk that won't even resemble
our sun anymore. Right, And once this whole process starts,
it's gonna take uh several billion years to even complete
(23:27):
that process. So now it happens overnight or a probably
about ten billion years from now, the Sun will just
be this massive hulk of carbon, right, like my brain
is right now. Not so massive that can we be
done now? I think? So? Okay, I mean there's a
lot more. We didn't even touch on solar wind and
things like that, but we leave it up to the
(23:47):
listener to pursue these. Yeah, sure, the listener or stuff
from the Science Lab or soon to be forthcoming sister
podcast with the esteemed Robert Lamb and his esteemed editor
Alison louder Milk, And then we can just talk about noodling. Yeah,
we'll go back to what we do best. It's just
(24:08):
bumpkin stuff, So Chuck, Josh, I can barely get it out,
I know. The listener, May I feel so defeated. I'm
just gonna call this the best part of this podcast.
Uh this is on human Experimentation, and we actually, as always,
(24:29):
if we put out a call for some random weirdness,
there's someone out there that listens to the show that
has been there and done that. Remember the kid whose
father used him as a human shield. Why? Uh So
I've got this one from Rebecca and she says this.
I just listened to the podcast on Human Experimentation. It
was thrilled that you featured something I can relate to
because I'm a former NASA human test subject. We just
(24:53):
talked about NASA. I know, weird funny how that works.
In two thousand six, I spent three months in a
bed at a negative six degree tilt. Isn't that crazy?
The effects of the human body at that angle are
very similar to what an astronaut goes through after spending
extended periods of time and space, which makes me wonder
how they figure that out? You know, because they're NASA,
(25:13):
that's the answer. Eventually, NASA hopes to take that information
they got from my time in bed to help astronauts
stay in space longer and travel further. From the Earth
and one day even land on Mars. As a test subject,
everything I did, from surfing the internet, eating, reading, even
using the bathroom was at an angle tilt. Five days
(25:34):
a week, I was wheeled to a lab where I
was attached to an elaborate pulley system that pulled me
onto a treadmill. What that was bolted to the wall.
I walked, jog and ran a few miles a day
to help my body avoid muscle atrophy. Of course, uh not.
Everyone selected for the study was so lucky, though half
of them did not get to run in this on
this unique contraption, so they were just in bed the
whole time. The date of the engineers got from my
(25:57):
running will help NASA figure out what types of exercise
astronauts will have to do to uh experience like long
extended trips into space. So while I didn't love everything
about it, going to the restroom, for example, it is
a thrilling thing to have been a part of. I'm
a huge fan and I'd like to learn neat stuff. Rebecca,
did you have that last part? No? No No, no, she
(26:17):
said that, Okay, yeah, more neat stuff. Well, thanks, Rebecca,
hats off to you for helping our astronauts. She didn't
mention if how much she got paid, if at all,
but I mean, and she did NASA's deep pockets, buddy,
that's what I hear. Yeah. Well, if you have any
stories about developing bed sores for the greater good of
advancing human knowledge, you can send in an email to
(26:38):
stuff Podcasts at how stuff works dot com. For more
on this and thousands of other topics, is that how
stuff works dot com. Want more how stuff works, check
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