February 21, 2019 • 46 mins
In the universe things tend to cluster. This means there’s a coherent structure to the universe and learning about clusters of stars – galaxies - helps us figure out what that structure is. Join Chuck and Josh on an amazing space voyage!
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Episode Transcript
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Speaker 1 (00:01):
Welcome to Stuff you Should Know from how Stuff Works
dot com. Hey, and welcome to the podcast. I'm Josh Clark,
and there's Star Child Chuck Bryant, and there's Moon Rock
Jerry Roland over there, and I'm just playing all Josh Clark.
Like I said, but this is the Galactic Federation of
(00:25):
Stuff you Should Know Episode of all Time. There was
my all boy. Yeah, there you go. Chucklates to get
nice and loaded when he talks about space stuff. Uh,
here's something that I found helpful for me that I
think it might help other dumb dumps, Like you're not
a dumb dump. I like that trip. By the way,
(00:46):
you click a circus peanut. It is circus peanut colored.
Oh my god, that is circus peanut orange pent. Dude.
I want to squeeze you do not um? All right,
all right, you can squeeze you Ready for this? So
if our solar system, which is the Sun and its
orbiting planets, moons, dust, gas, a lot of dust and gas,
(01:11):
solar system. Yeah, uh, if that was Let's say, if
the Sun was the size of a grain of sand,
then relatively our solar system would be like the size
of our hand. With that at the center. And then
if you extrapolate that, then our hand in relation to
(01:32):
the Milky Way galaxy would stretch the length width of
the United States and then keep going. Well, that's just
one of you know, billions of galaxies in the universe
if you go Solar system, galaxy, universe, and then so
the universe would be like our the United States and Canada. Well,
(01:54):
and I'm I am a dummy because I was like,
and so let's stand in Lebanon, Kansas. Is as the
geographic center not not as far as I recognize, But
we're not at the geographic center of our solar system,
is not the geographic center of the galaxy though, So
I was wrong. No, there's a long history, by the way,
it was beautiful. I love that, Thank you. Um, there's
(02:16):
a long history of assuming that we are at the
center of the universe, and then there's an equally almost
equally long history of science proving that now we're absolutely not.
And um, we finally figured out that we're about a
quarter of the way between the galactic center and the
edge of the Milky Way, and that checks out. So
(02:40):
we're so we're nowhere near the center of the Milky Way. Well,
because the center of the Milky Way is a supermassive
black hole. The universe itself is expanding, and it's expanding
faster than the speed of light, and galaxies are just
caught up in the in the motion, going through the motions,
and we're just here in this little rock called Earth
(03:01):
trying to figure out what what in the age is
going on? Yeah, during our you know, eighty to ninety
years here. Yeah, we're so luckily though, we figured out
how to encapsulate knowledge in the form of writing, so
earlier generations can or later generations can build on the
work of earlier generations, because we'd be toast if it
(03:21):
all just got reset after everybody's lifetime and you couldn't say, oh,
I've learned all this stuff. You know, people just keep
discovering the same things, which would be great for that
sense of discovery, but yeah, it wouldn't really help move
our species forward now, And that's what we're all about here, right, Yeah,
us and and the hubs um. So as far as
(03:44):
what we know about galaxy is now compared to the
very beginnings of this study. Of course, the Greeks were
looking up at the sky a long time before we were,
and they came up with this name galaxy's kuclose and
it means milky circle. Yeah, and which guess which word
we kept to describe galaxies, the milky not ku close.
(04:06):
So when you're saying, like, looking at galaxy up there,
you're saying, look at that milky up there. Oh right, right,
ku closes circle. Yeah, I looked it up. I'm like,
surely KU closes the milky one. But nope, no, surprising that.
So but the Greeks were like, it looks like a
milky circle, so we'll just go with that. Yeah. And
they were onto some like kind of like everything they
(04:26):
were doing back then, some stuff they got wrong, and
we're kind of ahead of their time and they're thinking
and other stuff they weren't quite right about because of technology.
But Galileo did. He was He looked up and it's like, hey,
that's a there's a bunch of stars up there. It
ain't mile congregating for a reason. Yeah, And so we
do pretty early on that, like we were in the
(04:46):
midst of some sort of group of stars. But for
most of the most of the era um where we
were looking up at the sky, at least in the
west I'm not sure about like the Muslim world. I
know that they kind of had their own like track
of astronomy and mathematics. It was, in many points in history,
far more advanced than what the West was at. UM.
(05:08):
But as far as the West is concerned, UM, they
didn't understand that this group was anything less than the
universe itself. They just looked out and they're like, well,
there's the universe. Everything we're seeing is the universe, and
that's all that there is. Not that Um. We possibly
lived in what were later called by UM a guy
(05:29):
named uh, I think Charles Messier who called them island
island universes. No, I'm sorry, it was Harlow Shapley. In
the early twentieth century. He started looking at some of
these things and realized that they they had the same
structure from that the Milky Way did we had kind
of identified that we were in our own little galaxy,
(05:51):
but that other stuff was beyond our own little galaxy,
and that they were their own galaxies. And so these
island universes came to be called milkies. Yeah, and so
did you pronounce some Shapley, Yeah, there's an e that's
not supposed to be in there because no one wants
to be called Harlow Shapeley. I'm sure. Uh so he
was actually right in this argument, right, this long standing
(06:15):
um sort of disagreement but debate with Messi A no,
Messi it was a couple hundred years before him. Well,
but no, the whole argument though. I mean they didn't
literally argue with each other because Messier was able to
encapsulate his ideas in the form of writing. Yeah, but
they had a long standing um again not to personal beef,
but debate because we didn't have the technology to prove
(06:38):
one or the other correct until Hubbs came along and
in uh he basically said that Shapley was correct. Yeah,
that that these little island universes weren't in the Milky Way.
They were way far outside of the Milky Way. In
the universe was astoundingly bigger than we we thought we
previously imagined. So we mentioned Hubs, the hubs, Dr Hubble
(07:00):
and it's awesome telescope, which did you know that's being replaced.
I mean, I don't think they're gonna like destroy it,
but surely not. It's being uh well, I guess sort
of replaced by the James Webb space telescope. How do
you mean being replaced, Like they're just gonna shoot it
out of the sky with a space what I was saying,
(07:21):
it out of field, destroy it. But it's being there's
a new a new guy on the block, and everybody's
hot and heavy, and his name is the James Webb Telescope,
which will be I think now it's been pushed back
to but this thing will supposed to be able to
observe like the formation of galaxies pretty pretty much. The
Hubble Telescope as it stands right now shows us I
(07:42):
think back to like four million years after the Big Bang,
which is astoundingly early in the universe's development. And the
whole point of astronomy is what they're doing is looking
back in time right the further away some object in
the sky. Is what you're seeing then is what that
object look like, say a billion or two billion, or
(08:03):
ten billion years ago. And so you can take the
structure of the object and compare it to objects that
are much younger that we know of today. They're closer,
and you can see how the universe has evolved, and
we can learn, you know, figure out some of the
mysteries of the universe, like where it came from, what
its structure is like. Right, So if Hubble can if Hubble,
that's great, great end of the world reference. But um,
(08:26):
if Hubble can see back to four million years after
the Big Bank, supposedly James Webb telescope can see back
to like two hundred million years, that is a hair's
breadth from the origin of the universe. Yeah, so it is.
It's the big guy in town, the new sheriff. Yeah.
I just don't want Hubs to get kicked to the curve.
The James Wood telescope is gonna mush his face out
(08:48):
of the way. Wait, you didn't say that James Wood's telescope.
You would, You'd be like Trump forever the telescope full
of right wing rage. Yeah, and very smart. I think
he is the highest i Q of anyone in Hollywood. Really,
he's like one sixthing. What he uh? Did you know
that he supposedly tried to thwart the nine eleven hijacking? No? What,
(09:13):
I think I need to look this up. Speaking from
the top of my head, but I'm pretty sure that
it is fact that he was on a flight with
one of the ringleaders and was like this guy is
on my flight and he's taken notes and something's fishy
here and I'm going to report it. And that ended
up being, you know, like Mohammed Atta or something. I
(09:35):
gotta look that up because I'm truly like flying by
the seat of my pants. But I think that's the
true thing. He also made an appearance on The Simpsons.
He was also the best part of the Stephen King
anthology film Cat's Eye. I don't remember his is the
man who tried to quit smoking? Is that what it
was called? Yeah, you remember that? That was him. I
(09:57):
don't remember James Witsby man. I think he was the
guy that is trying to quit smoking under threat of
violence to his family. Remember that. I haven't seen that
in a while. I have to check that out. Sure
it's being rebooted, all right, that's because it's space, alright.
So the various shapes edwin the hubs. Hubble classified these
(10:20):
uh and his Hubble sequence as elliptical, spiral, and irregular elliptical.
I mean, we'll go into detail in these, but about
six of all galaxies are elliptical roughly or so or spiral,
which is us and then anywhere from one irregular. Yes,
(10:40):
but elliptical, are there. There's a range of shape from circular,
which is E zero, all the way up to EAT seven,
which is the most elliptical, pretty much. Yeah, and you're like, okay, great,
so all you need is elliptical, it's all galaxies are.
But no, there's also something called spiral. And even though
Hubble classified them by their shape, it's really they're more
(11:05):
differentiated by their features and how bright right, right, they're bright.
They have stars, bright stars, lots of hot gas. They
tend to have arms that stretch out from them. Yeah. Like,
if you looked at pictures of the Milky Way galaxy,
it looks like a what does it look like like
someone spinning an octopus? A bit of a whirlpool? Sure,
(11:28):
it's spinning an octopus. I love that. Yeah, that was perfect.
That's what I wish. That's what the Greeks had come
up with instead of a Milky wayn't although they all
they saw was like a strip of white light, and
no one had any idea what the Milky Way looked
like until the twentieth century, so they all, right, all
these off the Greeks, everybody, I'm sorry, so, but spiral
(11:49):
are the brightest, right, they're the brightest because they have
the most bright stars um. Elliptical tend to sometimes not
have any bright stars at all. UM. And then the
other big difference between them is that elliptical are um
are disordered and chaotic, whereas spiral are much more orderly.
(12:10):
Where everything in the galaxy rotates in orbit around the
galaxy center in the exact same way and for the
exact same reasons that Earth rotates around the Sun, except
in this rotation, our solar system takes about two d
and thirty million years to make it all the way
around the Milky Way, rather than one year around the Sun. Yeah,
that's a big death. Yeah it is. And again with
(12:32):
the size as illustrated at the onset, that might make
a little more sense. Sure, the grain of sand in
the palm palm in the middle of the United States,
it's actually let's say the United States was that would
place us like, I don't know what, Kentucky? What the
center of the US? No, no, no, If the center
of the U s is leban On, Kansas, what is
(12:56):
in your book? I'll tell you. Got my own opinions
on that. Just no credit to leban On, Kansas, I
get it. Um I think it's actually a couple of
miles from there, but I don't know where that would
put us if we're in the like the what the
a third of the way between the edge and I
see what you're saying. If leban On, Kansas is the
middle and you not though, but let's just for the
(13:17):
sake of our in the east coast edge would the
outer edge? What would that put us? Yeah, I think
Kentucky is probably a pretty good roughly Kentucky or maybe
East Tennessee or Middle Tennessee something like that. Yeah, somewhere between,
just not in Memphis. Uh. Then the spirals are broken
(13:38):
down and subdivided into other categories. Um normal spiral. That's
where you have. That's sort of the classic disc shape
that we're thinking of, right, Yeah, that's the other feature
that they have is like a hump. They look like
a ufolge if you looked at a spiral galaxy from
the side especially, I guess in all right s A,
(14:02):
I think in A. Yeah, that's the largest nuclear pulge.
Nuclear bulges. So it's like great band name, it really is.
But the bulge is like it's got a hump on
the top and a hump on the bottom and then
a disc of stuff in the middle like a UFO.
That's what it looks like. Um, that's a that's a
classic spiral galaxy, right, which would be the normal. Then
(14:26):
they're the barred spiral that is has a disc shape
as well, with a bright center as well. I don't
get the difference then visually, so I think the difference is, Um,
the disc shape is with the barred spiral, the center
of it is drawn out so like in a in
(14:50):
a normal spiral, it's just a nice circle in the center,
a nice tidy sphere in the center, whereas in a
barred spiral that sphere is pulled out into an elliptical
it's self. So it's like a bar of light going
through you know, the middle of the galaxy, and that's
the galactic center and nucleus, all right. Uh. And then
we have our irregular as the third type of galaxy shape. Uh.
(15:13):
And these are very faint, very small Um, no bright center,
no spiral arms, just losers of the loser galaxies. So
they used to think that this was the evolution of galaxies,
that the different galaxies was like, yeah, either it started
as elliptical and then moved to um spiral or most
(15:37):
likely vice versa. Now we found that's not the case
at all. Interesting and they think probably you know, um,
galaxies tend to start out as spiral galaxies, the ordered
kind where everything's just going around nice and easy. Um,
and that the reason we have elliptical galaxies, the disordered kind,
is because a spiral merged with another spiral, which will
(16:00):
it into later. Yeah, the collisions of galaxies, yeah, which
I honestly didn't know that much about until this episode. Yeah,
and it sounds a lot scarier than it is. Certainly
not that scary, So don't be scared, everybody. You probably
wouldn't even notice. You just have an extra son five
billion years from there. I feel like we should take
a break. I think we should too. We made it
(16:20):
through page one, all right, we'll come back with page
to right after this, alright, chuck. So we're talking spiral
(16:51):
galaxies because that's what we care about, because that's what
the Milky Way is. That's right. Um, it's a spiral
bar galaxy to be particular. And so it's got that
center hump the galactic disc, and the galactic disc is
actually made up of a few different parts too. You've
got the nucleus, which is the center. You've got the bulge,
(17:12):
which you love the nuclear bulge like nine times already,
and then the spiral arms. These are like um accumulations
of stars, gas, dust, um, all sorts of stuff, planet,
solar systems, all that, And that's where we are right.
We're in a spiral arm. The Milky Way has four
spiral arms, two major and two minor, and we're in
(17:34):
a minor one Oriyan, which is still It's fine. We're
in a minor arm, but it's the orion arm, which
makes it pretty cool. So I guess it would not
have been a octopus spinning. That would be eight arms.
Well maybe we haven't discovered the other four yet, yes,
or maybe we're just a ceiling fan. Maybe. So I
like the spinning octopus the most. We need to get
some more arms. Then, you know, you shouldn't need octopus.
(17:57):
They're extraordinarily intelligent. Just y. I think we we've sung
our octopus praises over the years. But do you you're
you eating them those still, is what I'm saying. No,
I don't need octopus. Yeah, did you give them up
after our episode on it? Or yeah, we're on that
time is it okay to eat squid inc pasta? Though
(18:19):
squid they're stupid. Who cares about squid? I'll eat them
all day long. Luckily, that's what most calamaria is, a
squid or not even right? What is it? Then? In't
there like a big calamari hoax going on? I can
believe it's Some of that stuff is awfully rubbery. Yeah,
I think that's the deal, all right. So back to
the back to the shape of the galactic disc. There's
(18:42):
also the globular cluster um these are above and below
that disk, and then the halo, which is um hot
gas we think, and that is that that sort of
dim region that you see around the galaxy right when
you think of like the Milky Way from all the
pictures you've ever seen. What you're mostly thinking about is
the galactic disc. Popular clusters nobody really thinks much about.
(19:06):
But they're actually old super um, super burned out ancient
clumps of stars that formed in like the early galaxy,
that used up a bunch of stars, used up their
fuel really quickly, and now they're just kind of like
these dead balls that are in orbit around our galaxy
(19:26):
and we actually can use them and the effect that
our galaxy has on them. The title effects of gravity
to figure out how much mass our galaxy has. Yeah,
and you know gravity is what's holding all of this together.
And you would think when you see it's something like
the Milky Way galaxy. Uh, and you know gravity is
dependent upon mass, that that center would be where all
(19:48):
the masses. But that's not the case. It's a little
bit opposite of what you might think. Yeah, that that
um outer halo has about as much mass as the
intergalactic disc um the counterintuitive. Yeah, and because that halo
is made up mostly of gas and some dust um,
it's actually orbiting or rotating at a different rate or
(20:10):
different velocity I guess than the galactic disc. So there's
actually torque that gets produced because the galactic disc is
like dragging it along the arms. No, we found out recently,
like within the last month or two. I believe that
the actual the actual Milky Way galaxy is bent on
the ants. Like so it looks like an s from
(20:30):
the site, kind of like a sombrero with like the
front up and the back down. That's what the milky is.
Not an octopus, not the only fan. It's a crumpled sombrero,
maybe a nacho sombrero like the one Homer Simpson war. Right,
are the guys that make just wear the cowboy hat
with a front brim turned up like the cook at
(20:52):
the at the Cowboy camp. Sure, cookie cookie cook. Yeah.
And galaxies are very very far apart from one another.
The closest one to us, Uh, Andromeda is two point
two million light years away from us. And uh that's
a I mean, that's relatively close in the grand scheme,
(21:12):
but that's also pretty far apart. So I want to
there's this professor Barbara Ryden from Ohio State whose lecture
we came across, and she like just nails this right.
Two point two million light years is an astoundingly large distance, Right,
but it's actually really close for a galaxy because galaxies
(21:32):
are so huge. And the way that she put it,
like if you took a pair of ping pongs and
said one was balls ping pong balls, Yes, games of
ping pong, and he took two games. If you took
two ping pong balls and one was the Sun and
one was a neighboring star to the Sun, Alpha Centauri, okay, uh,
(21:54):
and you you put them relative to one another. Uh,
the ping pong balls would be as far apart as Columbus,
Ohio and Jacksonville, Florida. Okay, if you use ping pong
balls to be Andromeda and the Milky Way, here we go.
The distance would be three ft relative to one another. Interesting,
(22:15):
it is interesting. Yeah, yeah, it's at least as interesting
as your grain of singing in the palmyre this less
than one big mac. Maybe I didn't get it across.
Let me try another take. Okay, No, I thought it
was great. Um they use Uh, well, we should talk
about parsecs a little bit, just because of the Star
Wars thing, because a parsk is a unit of distance
(22:37):
that is three point to six light years. And you
remember in Star Wars the famous line from Han Solo.
Remember that he made the Kessel run in twelve parsecs. So,
as a young dumb kid, I thought that meant, you know,
like a parsak was like whatever, thirty seconds. So he
did this thing in a matter of minutes. Uh. And
(22:59):
then when I learned that it was a unit of
distance in that time, I think a lot of people's
inclination would be that that would be a mistake on
the part of the writer of Star Wars. But Star
Wars nerds are quick to point out that did no, no, no,
he he did mean a unit of distance, but he
actually skirted very close to a black hole on his
(23:20):
Kessel run and he actually shortened the normally eighteen par
sect route to twelve par secs. Wow, that's a big,
big short cut. So he cut out. He basically took
a shortcut. Yeah, not bad. Yeah, I'm just kind of
wondering this is, you know, all after the fact, and
they were like, oh, yeah, I think so. I got
(23:41):
a lot going for them. So as far as formation
and the galaxy, again, we're talking about going back further
than we can see with our current telescopes, even even
the web one upcoming. But we do have some pretty
good guesses, um that after the Big Bang about fourteen
billion years ago is when these galaxies formed from again
(24:04):
just dust and gas, lots of hydrogen gas in the
early universe. And yes, and the so from this expansion
that took place, Um, there were parts of the universe
that were less dense than other parts, and the denser
parts slowed down the expansion enough to for some of
(24:26):
this dust and gas to accumulate into balls, which uh,
one of two ways. Either those balls formed the earliest stars,
and then those stars started to to accumulate into a galaxy,
which to me doesn't make sense because if stars are
so far apart, how would they how would they have
any effect on one another to form a galaxy? Probably
(24:47):
not that. Instead, they think that the the clouds of
dust and gas um formed like what's called the proto galaxy,
and then from that more and more density was created,
more and more gravity pushed more and more dust and
gas together to form stars within this accumulation, which would
be kind of like that um that uh disc, the
(25:10):
gas disc that's flowing around the Milky Way. Yeah, and
it's interesting. It just seems like so much happened because
of um collapsing, things collapsing and on themselves. Yeah, yep,
really interesting, it really is. I mean because and this
is the whole reason why people study this stuff, is like,
when you start to understand this, you can start to
(25:32):
understand the very structure of the universe. And they've actually
started to map this to where they can they can
see where the dark matter is. Remember in that episode
that we they started to map dark matter in the universe,
and then also physical matter um and the map that
they're created, it's it's it looks like a cobweb. There's
(25:55):
lots of like um like spindle parts and thick clumps,
and then parts where there's voids, and it looks unsettlingly
like a close up of brain tissue of like neurons
in a brain, like voids in between areas of matter.
Really interesting. Um. So, we were talking about the the
(26:19):
distance between galaxies being really large, and that is true,
but also, like you said at the same time, galaxies
himself are so large that they they do collide. I mean,
should we go ahead and talk about that. I think
it's inevitable. But when they do collide, it's not like, uh,
everything within that galaxy so far apart. It's not like
(26:41):
what you might picture in your head, which is planets
and stars just smashing into each other all over the place. Right,
But you would think so. But the distances between stars
are so colossal that entire galaxies can just merge with
one another without any Star collisions are virtually none. Now
do they always merge or do sometimes they just kind
of passed through one another and come out the other side.
(27:03):
I think they can get both a little different there's
definitely types of universes that passed within. Yes, yeah, that's
all we're talking about right here, right now. Um, the
galaxies passed close enough to one another but don't necessarily merge,
but there their gravity still has an effect on one another.
(27:23):
There's a pair of galaxies called the Mice where they've
gotten close enough together that they've pulled stars toward one
another and they each have tails. Now, um, there's a
galaxy called the Cartwheel galaxy that a smaller galaxy passed
through and apparently created ripples. So just like um, as
as Professor Ryde and put it, just like you drop
(27:45):
a stone into a pond, it creates ripples in the water.
Those that other galaxy created ripples in this larger host universe.
So there's other things that can happen besides just a
straight up merger. But I think even in a merger,
sometimes some of the stars shake loup and end up
just they're they're out in space. Yeah that makes sense. Yeah, uh,
(28:07):
and when they do uh come together or collide. They
spiral galaxies generally, like the shape can change and they
generally go to the elliptical side. So if you see
a spiral galaxy like our own Milky Way, then chances
are it has never been in such a collision. Yeah.
They think that the spiral galaxies used to dominate. I
(28:28):
think you said, like sixty of galaxies today are the
elliptical ones, right, the disordered ones, And they think that
spiral galaxies used to be the majority, but so many
of them merged to become elliptical galaxy galaxies. That's what
we see the most of now. Yeah. About what do
they say about fifty of all galaxies at some point
(28:48):
have been involved in a collision. Yeah, I saw as
high as ninety in one place, and the Milky Way
will at some point, right, Yeah, I mean there, it's
kind of inevitable, isn't it. We're going to emerge with
Andromeda and about five billion years. In about three billion years,
we'll are We'll start affecting one another at the edges,
will start pulling one another into each other, and then
(29:09):
we'll eventually merge and become one called the milk Ameda Galaxy.
Is that really what it's going to be called? Yeah,
hopefully within five billion years will come up with a
better name. Interesting um and drama see yeah, drama way
the the and drama way and drama way good, yea,
(29:31):
the androw way. It's definitely better than the milk Omeda. Yeah,
but I mean we're not gonna be around our show
will be I don't know, it's possible. What if this
lived on billions of years from now. That's I mean,
that's what we're doing, right, that's what we're hoping for.
So uh. These galaxies um throughout the universe do exist
(29:51):
in galactic clusters. They um they are drawn to one
another by gravity. And we are in um what called
a poor cluster, which is less than a thousand like
way less Yeah, called the local group, and there's only
fifty of us. That's a good local band name, too,
I think. So it sounds like sort of a union group, yeah,
(30:11):
or like the local forty one or whatever. If you're
just playing for free beer, that's that's what you're doing
with your band. Local groups should be the name of
your band. That's great, that's pretty good. Uh. And then
there are rich clusters, and there are more than a
thousand in the rich clusters, right, and some some have
way more than a thousand. There's one called the Virgo
supercluster that has of these of galaxies all clustered together.
(30:37):
So think about you've got a planets orbiting a star,
solar system. Solar system is orbiting the center of the galaxy.
Galaxies can orbit one another or at least have effects
on one another's orbits. Everything clusters together in larger and
larger amounts thanks to gravity. Once you pass a certain
(30:59):
threshold old and electromagnetism and the strong and weak nuclear
force or not like the dominant forces, gravity takes over
and it does some interesting stuff to the structure, and
it's driving astronomers batty. They're like, surely there is some
rhyme or reason to this. There's some pattern to the
there's gotta be there, like Jim Carrey in the number
twenty three or something, you know. Um, And they think
(31:23):
that if they can study the evolution of galaxies, they
will be able to figure out the process that happens
or what the ultimate point will be. Let's do let's
take a break. We got more things, all right. So
(32:01):
we've talked a lot about the distance between galaxies, but
there's actually a name for that space in between galaxies
and these clusters that we talked about, called the intergalactic medium.
And uh, it is not empty. It's not just some void. Uh,
And we don't know exactly what's going on in there,
but we're studying it a lot. Um. They think that
(32:21):
there's probably some gas, because I think that's the fault
for everything in space, Like there's got to be some
gas in there, and probably some dust, and a lot
of it's super cold like you would expect. Yeah, this
is what the strange thing is though, but some of
it is really really hot. And did have they explained
that yet? Now? No, they're just taking a step. It's
a really neat age of discovery for astronomy, Like we're
(32:44):
getting better and better at looking out into the universe,
so we're finding out more and more. But just just
because we get data back doesn't mean we can necessarily
make heads or tails of it. Yeah, but yeah, there's
there's hot sections of the inner interstellar void what's it
called intergalactic medium and the intergalactic medium, and um which
(33:05):
has kind of an interstilleroid. Sure, and but I can't
start making up astronomy terms. I need to use the
real one. Um. But there's also like in these hot pockets, right,
there's some pepperoni and cheese in there that will take
the roof clean off of your mouth. Um, there's hot
metals which would also burn the roof of your mouth
to a million degrees kelvin. Yeah, and I mean that
(33:28):
is the difference to um from the cold um intergalactic
medium about two degrees kelvin all the way to millions
of degrees. Yeah, that's quite a span. And no idea
why or what it's doing there, what's going to become
of it or if it used to be something else.
We just don't understand if it follows a pattern, and
it seems to yeah for sure. Um. And thanks to
(33:51):
Hubble too, we also have Hubble's law, which and it's
so hard to believe he was doing all this in
THEOD I know he was a boss. Yeah, like really really, Uh,
that's that's amazing. He also wants beat up James Webb
in a bar fight, which makes this whole telescope thing
really ironic. But Helpal's law states this observation that he
made way back when where and this is an actual
(34:14):
graph of this relationship. But he basically was like, you
know what, everything is moving away from us. Like every
time I look at something through this telescope, it's everything
is moving away and not only that, but the further
way it is, the faster it's moving away, which is
mind boggling. Yeah, because you can think, like, all right,
the universe is expanding, so that's fine, everything's moving away
(34:37):
from us. It also suggests that there's no center to
the universe. This is where that comes from, because everything,
no matter what direction you look in, it's moving away
from us. You would think that, but doesn't that mean
we're the center? Bite your tongue, um, But that's the
cosmological principle that everything is expanding the entire universe, not
(34:57):
everything in the universe is expanding within the uni the
very universe itself is expanded, right, And since some things
are moving away the further the further they are away,
the faster they're moving away from us, that means that
there's plenty of the universe that we will we can
never possibly detect, because if even if we get up
(35:19):
to the speed of light for travel, some parts of
the universe, the furthest away parts are actually spreading at
faster than the speed of light. So it is it
was cosmically impossible for us to ever detect a large
part of the universe, which is why when we're talking
about the universe that we're talking about and observing. That's
(35:40):
called the visible universe. But that's probably just a relatively
small chunk of the universe itself, which might be infinite
for all we know, and we may never know what
the universe is really shaped, like, what it's made of,
how big it is um because of this expansion that's
actually speeding up and accelerating beyond our our ability to detected. Amazing,
(36:01):
It's kind of sad in a way. Yeah, And eventually
this is this is the most mind blowing thing I've
ever heard. You're the expansion will accelerate so much that
the moon will no longer be visible to us, like
nothing will be visible to us. And on a long
enough time scale, I believe you wouldn't even be able
to detect your hand in front of your face if
(36:23):
you could, if it was physically possible, because of that
expansion of light. Right, So, the universe expanding is actually
pulling light out of its out of the visible spectrum
into a longer wavelength in what's called red shifting, because
the red is the longer wavelength end of the visible spectrum.
(36:44):
And so what Hubble did, what Hubble detected is called
the red shift. Everything's moving away from us. Yeah, which
we could observe because of X rays, right uh, because
the infrared I think, Yeah, man, I know I love
this stuff. Glad you do. I'm aroused. Oh goodness. Um So,
(37:07):
I guess if you're aroused, we should talk about active
galaxies because you know, I'm still waiting on my squeeze
by the way, Oh you're peanut squeeze all right, just
hang on. That's your little treat if we finished they
if we um. So, if you're looking at a normal galaxy,
(37:27):
let's say like the Milky Way, I guess all this
light or most of it that you're seeing UM is
pretty evenly distributed throughout that galaxy. Because it says, you know,
the same those same galaxies that have the even distribution
of light UM, they have looked at it through X
ray and ultra violet and infrared, and it seems like
(37:48):
they are giving off that energy from the nucleus. And
that is the active galaxy okay, yeah, which is a
very small percentage of the overall galaxy. Right. So the
light and energy in a normal galaxy and non active galley, see,
it's distributed evenly throughout, whereas in an active galaxy, all
of that light and energy is coming from the center. Yeah,
but they're I mean one of those like one how
(38:10):
I was gonna say one percent. I don't know if
I'm not you with the percentages, I know they're they're
fairly rare from what we actually I didn't have a percentage,
but it just has a very small percentage. Yeah, I
think they've they've discovered like a couple of thousands so far,
or less than less than half a million, less than
a million, which is a very small amount. But the
distinction between them and a regular galaxy is again, all
(38:32):
of that light, all of that energy is coming from
a very small portion of the galaxy rather than the
galaxy as a whole putting out all this light and energy.
This it's all concentrated in the middle. It's very weird.
And upon closer inspection, these things that look as bright
as you know, galaxies that are relatively close to us,
(38:52):
we're finding are actually billions and billions and billions of
miles light year I'm sorry, light years away from us.
But they seem just as bright. Makes them super energetic.
So they started to try to figure out what's going on,
and they think that the culprit are super massive black
holes at the center of these galaxies. Well, and that's
what it's at the center of our own. I suspect
(39:13):
there's a supermassive black hole at the center of every galaxy.
That's my big prediction for for the second decade, the
third decade of the century. We're going to figure that out. Okay, Um,
if you're talking active galaxies, there are four classifications within
that uh genre and uh they say that if it's
(39:34):
basically it may not be structural. It might depend more
on like the angle that we're viewing these things. Yeah,
like they're all probably the same thing, right, But for
that classification, it's the Seafort galaxies, radio galaxies, quasars and blazers. Yeah,
and radio galaxy. I only ran across here. Everybody else
just says it's Seafort, blazers and quasars. Yeah, radio galaxies
(39:57):
point oh one percent of all galaxies. So I think
freud Rinch has made that up. I think stock in
radio galaxies or something, so he slipped it in. That's funny. Um,
Carl Seafort coined the obviously in n the Seafort galaxies,
and um, what's the deal with these. So let's see,
(40:19):
the Seafort galaxy has no jets. So this is the
thing about an active galaxy, and this is why they
think there's a supermassive black hole at the center. They
think that the accretion disc of gas and dust and
everything that's just swirling circling the drain of the event
horizon of the black hole. UM. As this gas and
dust circles, friction develops, speed develops, and it gets so
(40:43):
hot that some of that material doesn't get stuck in
the black hole instead gets shot away above and below
the black hole into jets that are so tall they're
as tall as the galaxy is wide. They're just huge,
huge energetic fountains of of just basically pure energy and
(41:06):
um that's what causes this brightness that can be seen
from so far away and depending on the angle of
it relative to us, we've basically said it's a Seafort galaxy,
which means that we're probably seeing it from the side,
and so we can't see the jets because they're not
pointed to us. And then there's blazars and quasars too,
and in the case of the blaze, are that's looking
basically straight on it that jet that you were talking
(41:28):
about coming right at you, right at your face, looking
down the barrel of a blazer. And then the quasars. Uh,
we discovered those in the nineteen sixties. Um, they've discovered
what like thirteen thousand, but they think there could be
up to a hundred thousand. And these are billions of
light years away from us, and these are the ones
that are the most energetic of them all. Yeah. So
(41:49):
if you look at a quasar something like that and
the jets coming out of the quasar, what you're actually
seeing is basically the most potent particle accelerator in the universe,
just shooting those energetic particles into space. It's amazing. I
can't imagine what it would be like to be anywhere
near something like that. You die, yeah, but it's like
(42:11):
you were just there in spirit or something, you know.
Or if you could see it with a space telescope,
that'd be great too. I'd settle for that for the
James the James Woods space telecop What else you got? Oh,
the Starburst galaxy thing at the end was kind of interesting. Yeah. This, Um,
I just want to go on record is saying Starburst
(42:32):
is one of the most beautiful words ever. You like that,
I love it. Yeah, I like that too. Attached star
or burst onto anything. Well, that's not true, because a
fecal burst, fecal first star that sounds prettier than fecal burst,
a fecal star, I sure, I guess. Yeah, it's just
about everything sounds better than fecal burst. So um galaxy says,
(42:57):
we know them have a very low rate of new
star ours being formed, usually about one a year, but
the star Wars galaxies produce more than a hundred a year,
which is amazing. Yeah, it is compared to the rest,
hundred times more amazing than a regular galaxy. That's true.
They also think that they burn themselves out rather quickly,
and that those might actually be the globular clusters that
(43:19):
end up just kind of hanging around a real galaxy. Well,
they say, the stars that burn the brightest. Yeah, like
Jimi Hendrix. Yeah, the Seven Club, all globular clusters, starburst.
That's it. That's it. If you want them more about galaxies, friends,
there is a whole universe out there for you to
(43:40):
go check out, and you can start on the internet,
So go check it out there. Uh. And since I
said something weird like that, it's time for listener mail.
So in lieu of listener mail, okay, we uh, we
got a lot of feedback on our stalker episode, which
kudos to you, that's your idea, and they ended up
(44:01):
being a really good episode, I think. Um, but we
got a lot of emails from um, both men and
women who had been victims of stalking. Some people who
didn't even know they've been stocked until they listen to
the episode you're like, oh, okay, I was stalked. Yeah,
and some really just heartbreaking, scary, scary, in depth, long
stories and we heard people who had to move and
(44:22):
we're still in the midst of it. It's just awful.
It's tough stuff. So we're not gonna read any of
those because they are very personal stories and um, they're
all anonymous, yeah, most most of them were. UM, but
we just want to say thanks to everyone for being
brave enough to share your story with us and just
direct people to get help if you're being stalked. Uh.
(44:43):
It is serious stuff and I hope that podcast really
got that across. Yeah, And that was one thing almost
universally that we heard was that like, thank you for
saying like go find local help because it's out there,
and that's a huge first step. Yeah, and a lot
of these people, like just like we had talked about,
kind of went through the batim steps of people at
work thought I was just overreacting, and even my family
(45:05):
thought I was blowing it out of proportion. Why didn't
you press charges the first time? Do you wait for?
You know that? Yeah, blaming the victim, basically all that stuff. So, uh,
you can reach out to the Stalking Resource Center, the
National Center for Victims of Crime. It's a good place
to start. Um. There are plenty of it. Depending on
what country you're from. There are different organizations to see
(45:26):
one from the UK where you can report a stalker
um and in fact, one of our listeners from the
UK had a really hard time over there being taken seriously. Uh.
And then there's also rain are AI n N who
is in their twenty fi year and they have some
good resources for you as well, So just check it
(45:46):
out online. Nice work, Chuck, Nice work, Josh. All right, Well,
thank you everybody who wrote in, And if you want
to write in for a new reason, you can go
to our website at stuff you Should Know dot com
and check out the social links. I have a website
to d Josh Clarkway dot com and you can send
us all an email me, Chuck, Jerry, Everybody to Stuff
(46:06):
podcast at how stuff works dot com. For more on
this and thousands of other topics, visit how stuff works
dot com. M
Welcome to Stuff you Should Know from how Stuff Works
dot com. Hey, and welcome to the podcast. I'm Josh Clark,
and there's Star Child Chuck Bryant, and there's Moon Rock
Jerry Roland over there, and I'm just playing all Josh Clark.
Like I said, but this is the Galactic Federation of
(00:25):
Stuff you Should Know Episode of all Time. There was
my all boy. Yeah, there you go. Chucklates to get
nice and loaded when he talks about space stuff. Uh,
here's something that I found helpful for me that I
think it might help other dumb dumps, Like you're not
a dumb dump. I like that trip. By the way,
(00:46):
you click a circus peanut. It is circus peanut colored.
Oh my god, that is circus peanut orange pent. Dude.
I want to squeeze you do not um? All right,
all right, you can squeeze you Ready for this? So
if our solar system, which is the Sun and its
orbiting planets, moons, dust, gas, a lot of dust and gas,
(01:11):
solar system. Yeah, uh, if that was Let's say, if
the Sun was the size of a grain of sand,
then relatively our solar system would be like the size
of our hand. With that at the center. And then
if you extrapolate that, then our hand in relation to
(01:32):
the Milky Way galaxy would stretch the length width of
the United States and then keep going. Well, that's just
one of you know, billions of galaxies in the universe
if you go Solar system, galaxy, universe, and then so
the universe would be like our the United States and Canada. Well,
(01:54):
and I'm I am a dummy because I was like,
and so let's stand in Lebanon, Kansas. Is as the
geographic center not not as far as I recognize, But
we're not at the geographic center of our solar system,
is not the geographic center of the galaxy though, So
I was wrong. No, there's a long history, by the way,
it was beautiful. I love that, Thank you. Um, there's
(02:16):
a long history of assuming that we are at the
center of the universe, and then there's an equally almost
equally long history of science proving that now we're absolutely not.
And um, we finally figured out that we're about a
quarter of the way between the galactic center and the
edge of the Milky Way, and that checks out. So
(02:40):
we're so we're nowhere near the center of the Milky Way. Well,
because the center of the Milky Way is a supermassive
black hole. The universe itself is expanding, and it's expanding
faster than the speed of light, and galaxies are just
caught up in the in the motion, going through the motions,
and we're just here in this little rock called Earth
(03:01):
trying to figure out what what in the age is
going on? Yeah, during our you know, eighty to ninety
years here. Yeah, we're so luckily though, we figured out
how to encapsulate knowledge in the form of writing, so
earlier generations can or later generations can build on the
work of earlier generations, because we'd be toast if it
(03:21):
all just got reset after everybody's lifetime and you couldn't say, oh,
I've learned all this stuff. You know, people just keep
discovering the same things, which would be great for that
sense of discovery, but yeah, it wouldn't really help move
our species forward now, And that's what we're all about here, right, Yeah,
us and and the hubs um. So as far as
(03:44):
what we know about galaxy is now compared to the
very beginnings of this study. Of course, the Greeks were
looking up at the sky a long time before we were,
and they came up with this name galaxy's kuclose and
it means milky circle. Yeah, and which guess which word
we kept to describe galaxies, the milky not ku close.
(04:06):
So when you're saying, like, looking at galaxy up there,
you're saying, look at that milky up there. Oh right, right,
ku closes circle. Yeah, I looked it up. I'm like,
surely KU closes the milky one. But nope, no, surprising that.
So but the Greeks were like, it looks like a
milky circle, so we'll just go with that. Yeah. And
they were onto some like kind of like everything they
(04:26):
were doing back then, some stuff they got wrong, and
we're kind of ahead of their time and they're thinking
and other stuff they weren't quite right about because of technology.
But Galileo did. He was He looked up and it's like, hey,
that's a there's a bunch of stars up there. It
ain't mile congregating for a reason. Yeah, And so we
do pretty early on that, like we were in the
(04:46):
midst of some sort of group of stars. But for
most of the most of the era um where we
were looking up at the sky, at least in the
west I'm not sure about like the Muslim world. I
know that they kind of had their own like track
of astronomy and mathematics. It was, in many points in history,
far more advanced than what the West was at. UM.
(05:08):
But as far as the West is concerned, UM, they
didn't understand that this group was anything less than the
universe itself. They just looked out and they're like, well,
there's the universe. Everything we're seeing is the universe, and
that's all that there is. Not that Um. We possibly
lived in what were later called by UM a guy
(05:29):
named uh, I think Charles Messier who called them island
island universes. No, I'm sorry, it was Harlow Shapley. In
the early twentieth century. He started looking at some of
these things and realized that they they had the same
structure from that the Milky Way did we had kind
of identified that we were in our own little galaxy,
(05:51):
but that other stuff was beyond our own little galaxy,
and that they were their own galaxies. And so these
island universes came to be called milkies. Yeah, and so
did you pronounce some Shapley, Yeah, there's an e that's
not supposed to be in there because no one wants
to be called Harlow Shapeley. I'm sure. Uh so he
was actually right in this argument, right, this long standing
(06:15):
um sort of disagreement but debate with Messi A no,
Messi it was a couple hundred years before him. Well,
but no, the whole argument though. I mean they didn't
literally argue with each other because Messier was able to
encapsulate his ideas in the form of writing. Yeah, but
they had a long standing um again not to personal beef,
but debate because we didn't have the technology to prove
(06:38):
one or the other correct until Hubbs came along and
in uh he basically said that Shapley was correct. Yeah,
that that these little island universes weren't in the Milky Way.
They were way far outside of the Milky Way. In
the universe was astoundingly bigger than we we thought we
previously imagined. So we mentioned Hubs, the hubs, Dr Hubble
(07:00):
and it's awesome telescope, which did you know that's being replaced.
I mean, I don't think they're gonna like destroy it,
but surely not. It's being uh well, I guess sort
of replaced by the James Webb space telescope. How do
you mean being replaced, Like they're just gonna shoot it
out of the sky with a space what I was saying,
(07:21):
it out of field, destroy it. But it's being there's
a new a new guy on the block, and everybody's
hot and heavy, and his name is the James Webb Telescope,
which will be I think now it's been pushed back
to but this thing will supposed to be able to
observe like the formation of galaxies pretty pretty much. The
Hubble Telescope as it stands right now shows us I
(07:42):
think back to like four million years after the Big Bang,
which is astoundingly early in the universe's development. And the
whole point of astronomy is what they're doing is looking
back in time right the further away some object in
the sky. Is what you're seeing then is what that
object look like, say a billion or two billion, or
(08:03):
ten billion years ago. And so you can take the
structure of the object and compare it to objects that
are much younger that we know of today. They're closer,
and you can see how the universe has evolved, and
we can learn, you know, figure out some of the
mysteries of the universe, like where it came from, what
its structure is like. Right, So if Hubble can if Hubble,
that's great, great end of the world reference. But um,
(08:26):
if Hubble can see back to four million years after
the Big Bank, supposedly James Webb telescope can see back
to like two hundred million years, that is a hair's
breadth from the origin of the universe. Yeah, so it is.
It's the big guy in town, the new sheriff. Yeah.
I just don't want Hubs to get kicked to the curve.
The James Wood telescope is gonna mush his face out
(08:48):
of the way. Wait, you didn't say that James Wood's telescope.
You would, You'd be like Trump forever the telescope full
of right wing rage. Yeah, and very smart. I think
he is the highest i Q of anyone in Hollywood. Really,
he's like one sixthing. What he uh? Did you know
that he supposedly tried to thwart the nine eleven hijacking? No? What,
(09:13):
I think I need to look this up. Speaking from
the top of my head, but I'm pretty sure that
it is fact that he was on a flight with
one of the ringleaders and was like this guy is
on my flight and he's taken notes and something's fishy
here and I'm going to report it. And that ended
up being, you know, like Mohammed Atta or something. I
(09:35):
gotta look that up because I'm truly like flying by
the seat of my pants. But I think that's the
true thing. He also made an appearance on The Simpsons.
He was also the best part of the Stephen King
anthology film Cat's Eye. I don't remember his is the
man who tried to quit smoking? Is that what it
was called? Yeah, you remember that? That was him. I
(09:57):
don't remember James Witsby man. I think he was the
guy that is trying to quit smoking under threat of
violence to his family. Remember that. I haven't seen that
in a while. I have to check that out. Sure
it's being rebooted, all right, that's because it's space, alright.
So the various shapes edwin the hubs. Hubble classified these
(10:20):
uh and his Hubble sequence as elliptical, spiral, and irregular elliptical.
I mean, we'll go into detail in these, but about
six of all galaxies are elliptical roughly or so or spiral,
which is us and then anywhere from one irregular. Yes,
(10:40):
but elliptical, are there. There's a range of shape from circular,
which is E zero, all the way up to EAT seven,
which is the most elliptical, pretty much. Yeah, and you're like, okay, great,
so all you need is elliptical, it's all galaxies are.
But no, there's also something called spiral. And even though
Hubble classified them by their shape, it's really they're more
(11:05):
differentiated by their features and how bright right, right, they're bright.
They have stars, bright stars, lots of hot gas. They
tend to have arms that stretch out from them. Yeah. Like,
if you looked at pictures of the Milky Way galaxy,
it looks like a what does it look like like
someone spinning an octopus? A bit of a whirlpool? Sure,
(11:28):
it's spinning an octopus. I love that. Yeah, that was perfect.
That's what I wish. That's what the Greeks had come
up with instead of a Milky wayn't although they all
they saw was like a strip of white light, and
no one had any idea what the Milky Way looked
like until the twentieth century, so they all, right, all
these off the Greeks, everybody, I'm sorry, so, but spiral
(11:49):
are the brightest, right, they're the brightest because they have
the most bright stars um. Elliptical tend to sometimes not
have any bright stars at all. UM. And then the
other big difference between them is that elliptical are um
are disordered and chaotic, whereas spiral are much more orderly.
(12:10):
Where everything in the galaxy rotates in orbit around the
galaxy center in the exact same way and for the
exact same reasons that Earth rotates around the Sun, except
in this rotation, our solar system takes about two d
and thirty million years to make it all the way
around the Milky Way, rather than one year around the Sun. Yeah,
that's a big death. Yeah it is. And again with
(12:32):
the size as illustrated at the onset, that might make
a little more sense. Sure, the grain of sand in
the palm palm in the middle of the United States,
it's actually let's say the United States was that would
place us like, I don't know what, Kentucky? What the
center of the US? No, no, no, If the center
of the U s is leban On, Kansas, what is
(12:56):
in your book? I'll tell you. Got my own opinions
on that. Just no credit to leban On, Kansas, I
get it. Um I think it's actually a couple of
miles from there, but I don't know where that would
put us if we're in the like the what the
a third of the way between the edge and I
see what you're saying. If leban On, Kansas is the
middle and you not though, but let's just for the
(13:17):
sake of our in the east coast edge would the
outer edge? What would that put us? Yeah, I think
Kentucky is probably a pretty good roughly Kentucky or maybe
East Tennessee or Middle Tennessee something like that. Yeah, somewhere between,
just not in Memphis. Uh. Then the spirals are broken
(13:38):
down and subdivided into other categories. Um normal spiral. That's
where you have. That's sort of the classic disc shape
that we're thinking of, right, Yeah, that's the other feature
that they have is like a hump. They look like
a ufolge if you looked at a spiral galaxy from
the side especially, I guess in all right s A,
(14:02):
I think in A. Yeah, that's the largest nuclear pulge.
Nuclear bulges. So it's like great band name, it really is.
But the bulge is like it's got a hump on
the top and a hump on the bottom and then
a disc of stuff in the middle like a UFO.
That's what it looks like. Um, that's a that's a
classic spiral galaxy, right, which would be the normal. Then
(14:26):
they're the barred spiral that is has a disc shape
as well, with a bright center as well. I don't
get the difference then visually, so I think the difference is, Um,
the disc shape is with the barred spiral, the center
of it is drawn out so like in a in
(14:50):
a normal spiral, it's just a nice circle in the center,
a nice tidy sphere in the center, whereas in a
barred spiral that sphere is pulled out into an elliptical
it's self. So it's like a bar of light going
through you know, the middle of the galaxy, and that's
the galactic center and nucleus, all right. Uh. And then
we have our irregular as the third type of galaxy shape. Uh.
(15:13):
And these are very faint, very small Um, no bright center,
no spiral arms, just losers of the loser galaxies. So
they used to think that this was the evolution of galaxies,
that the different galaxies was like, yeah, either it started
as elliptical and then moved to um spiral or most
(15:37):
likely vice versa. Now we found that's not the case
at all. Interesting and they think probably you know, um,
galaxies tend to start out as spiral galaxies, the ordered
kind where everything's just going around nice and easy. Um,
and that the reason we have elliptical galaxies, the disordered kind,
is because a spiral merged with another spiral, which will
(16:00):
it into later. Yeah, the collisions of galaxies, yeah, which
I honestly didn't know that much about until this episode. Yeah,
and it sounds a lot scarier than it is. Certainly
not that scary, So don't be scared, everybody. You probably
wouldn't even notice. You just have an extra son five
billion years from there. I feel like we should take
a break. I think we should too. We made it
(16:20):
through page one, all right, we'll come back with page
to right after this, alright, chuck. So we're talking spiral
(16:51):
galaxies because that's what we care about, because that's what
the Milky Way is. That's right. Um, it's a spiral
bar galaxy to be particular. And so it's got that
center hump the galactic disc, and the galactic disc is
actually made up of a few different parts too. You've
got the nucleus, which is the center. You've got the bulge,
(17:12):
which you love the nuclear bulge like nine times already,
and then the spiral arms. These are like um accumulations
of stars, gas, dust, um, all sorts of stuff, planet,
solar systems, all that, And that's where we are right.
We're in a spiral arm. The Milky Way has four
spiral arms, two major and two minor, and we're in
(17:34):
a minor one Oriyan, which is still It's fine. We're
in a minor arm, but it's the orion arm, which
makes it pretty cool. So I guess it would not
have been a octopus spinning. That would be eight arms.
Well maybe we haven't discovered the other four yet, yes,
or maybe we're just a ceiling fan. Maybe. So I
like the spinning octopus the most. We need to get
some more arms. Then, you know, you shouldn't need octopus.
(17:57):
They're extraordinarily intelligent. Just y. I think we we've sung
our octopus praises over the years. But do you you're
you eating them those still, is what I'm saying. No,
I don't need octopus. Yeah, did you give them up
after our episode on it? Or yeah, we're on that
time is it okay to eat squid inc pasta? Though
(18:19):
squid they're stupid. Who cares about squid? I'll eat them
all day long. Luckily, that's what most calamaria is, a
squid or not even right? What is it? Then? In't
there like a big calamari hoax going on? I can
believe it's Some of that stuff is awfully rubbery. Yeah,
I think that's the deal, all right. So back to
the back to the shape of the galactic disc. There's
(18:42):
also the globular cluster um these are above and below
that disk, and then the halo, which is um hot
gas we think, and that is that that sort of
dim region that you see around the galaxy right when
you think of like the Milky Way from all the
pictures you've ever seen. What you're mostly thinking about is
the galactic disc. Popular clusters nobody really thinks much about.
(19:06):
But they're actually old super um, super burned out ancient
clumps of stars that formed in like the early galaxy,
that used up a bunch of stars, used up their
fuel really quickly, and now they're just kind of like
these dead balls that are in orbit around our galaxy
(19:26):
and we actually can use them and the effect that
our galaxy has on them. The title effects of gravity
to figure out how much mass our galaxy has. Yeah,
and you know gravity is what's holding all of this together.
And you would think when you see it's something like
the Milky Way galaxy. Uh, and you know gravity is
dependent upon mass, that that center would be where all
(19:48):
the masses. But that's not the case. It's a little
bit opposite of what you might think. Yeah, that that
um outer halo has about as much mass as the
intergalactic disc um the counterintuitive. Yeah, and because that halo
is made up mostly of gas and some dust um,
it's actually orbiting or rotating at a different rate or
(20:10):
different velocity I guess than the galactic disc. So there's
actually torque that gets produced because the galactic disc is
like dragging it along the arms. No, we found out recently,
like within the last month or two. I believe that
the actual the actual Milky Way galaxy is bent on
the ants. Like so it looks like an s from
(20:30):
the site, kind of like a sombrero with like the
front up and the back down. That's what the milky is.
Not an octopus, not the only fan. It's a crumpled sombrero,
maybe a nacho sombrero like the one Homer Simpson war. Right,
are the guys that make just wear the cowboy hat
with a front brim turned up like the cook at
(20:52):
the at the Cowboy camp. Sure, cookie cookie cook. Yeah.
And galaxies are very very far apart from one another.
The closest one to us, Uh, Andromeda is two point
two million light years away from us. And uh that's
a I mean, that's relatively close in the grand scheme,
(21:12):
but that's also pretty far apart. So I want to
there's this professor Barbara Ryden from Ohio State whose lecture
we came across, and she like just nails this right.
Two point two million light years is an astoundingly large distance, Right,
but it's actually really close for a galaxy because galaxies
(21:32):
are so huge. And the way that she put it,
like if you took a pair of ping pongs and
said one was balls ping pong balls, Yes, games of
ping pong, and he took two games. If you took
two ping pong balls and one was the Sun and
one was a neighboring star to the Sun, Alpha Centauri, okay, uh,
(21:54):
and you you put them relative to one another. Uh,
the ping pong balls would be as far apart as Columbus,
Ohio and Jacksonville, Florida. Okay, if you use ping pong
balls to be Andromeda and the Milky Way, here we go.
The distance would be three ft relative to one another. Interesting,
(22:15):
it is interesting. Yeah, yeah, it's at least as interesting
as your grain of singing in the palmyre this less
than one big mac. Maybe I didn't get it across.
Let me try another take. Okay, No, I thought it
was great. Um they use Uh, well, we should talk
about parsecs a little bit, just because of the Star
Wars thing, because a parsk is a unit of distance
(22:37):
that is three point to six light years. And you
remember in Star Wars the famous line from Han Solo.
Remember that he made the Kessel run in twelve parsecs. So,
as a young dumb kid, I thought that meant, you know,
like a parsak was like whatever, thirty seconds. So he
did this thing in a matter of minutes. Uh. And
(22:59):
then when I learned that it was a unit of
distance in that time, I think a lot of people's
inclination would be that that would be a mistake on
the part of the writer of Star Wars. But Star
Wars nerds are quick to point out that did no, no, no,
he he did mean a unit of distance, but he
actually skirted very close to a black hole on his
(23:20):
Kessel run and he actually shortened the normally eighteen par
sect route to twelve par secs. Wow, that's a big,
big short cut. So he cut out. He basically took
a shortcut. Yeah, not bad. Yeah, I'm just kind of
wondering this is, you know, all after the fact, and
they were like, oh, yeah, I think so. I got
(23:41):
a lot going for them. So as far as formation
and the galaxy, again, we're talking about going back further
than we can see with our current telescopes, even even
the web one upcoming. But we do have some pretty
good guesses, um that after the Big Bang about fourteen
billion years ago is when these galaxies formed from again
(24:04):
just dust and gas, lots of hydrogen gas in the
early universe. And yes, and the so from this expansion
that took place, Um, there were parts of the universe
that were less dense than other parts, and the denser
parts slowed down the expansion enough to for some of
(24:26):
this dust and gas to accumulate into balls, which uh,
one of two ways. Either those balls formed the earliest stars,
and then those stars started to to accumulate into a galaxy,
which to me doesn't make sense because if stars are
so far apart, how would they how would they have
any effect on one another to form a galaxy? Probably
(24:47):
not that. Instead, they think that the the clouds of
dust and gas um formed like what's called the proto galaxy,
and then from that more and more density was created,
more and more gravity pushed more and more dust and
gas together to form stars within this accumulation, which would
be kind of like that um that uh disc, the
(25:10):
gas disc that's flowing around the Milky Way. Yeah, and
it's interesting. It just seems like so much happened because
of um collapsing, things collapsing and on themselves. Yeah, yep,
really interesting, it really is. I mean because and this
is the whole reason why people study this stuff, is like,
when you start to understand this, you can start to
(25:32):
understand the very structure of the universe. And they've actually
started to map this to where they can they can
see where the dark matter is. Remember in that episode
that we they started to map dark matter in the universe,
and then also physical matter um and the map that
they're created, it's it's it looks like a cobweb. There's
(25:55):
lots of like um like spindle parts and thick clumps,
and then parts where there's voids, and it looks unsettlingly
like a close up of brain tissue of like neurons
in a brain, like voids in between areas of matter.
Really interesting. Um. So, we were talking about the the
(26:19):
distance between galaxies being really large, and that is true,
but also, like you said at the same time, galaxies
himself are so large that they they do collide. I mean,
should we go ahead and talk about that. I think
it's inevitable. But when they do collide, it's not like, uh,
everything within that galaxy so far apart. It's not like
(26:41):
what you might picture in your head, which is planets
and stars just smashing into each other all over the place. Right,
But you would think so. But the distances between stars
are so colossal that entire galaxies can just merge with
one another without any Star collisions are virtually none. Now
do they always merge or do sometimes they just kind
of passed through one another and come out the other side.
(27:03):
I think they can get both a little different there's
definitely types of universes that passed within. Yes, yeah, that's
all we're talking about right here, right now. Um, the
galaxies passed close enough to one another but don't necessarily merge,
but there their gravity still has an effect on one another.
(27:23):
There's a pair of galaxies called the Mice where they've
gotten close enough together that they've pulled stars toward one
another and they each have tails. Now, um, there's a
galaxy called the Cartwheel galaxy that a smaller galaxy passed
through and apparently created ripples. So just like um, as
as Professor Ryde and put it, just like you drop
(27:45):
a stone into a pond, it creates ripples in the water.
Those that other galaxy created ripples in this larger host universe.
So there's other things that can happen besides just a
straight up merger. But I think even in a merger,
sometimes some of the stars shake loup and end up
just they're they're out in space. Yeah that makes sense. Yeah, uh,
(28:07):
and when they do uh come together or collide. They
spiral galaxies generally, like the shape can change and they
generally go to the elliptical side. So if you see
a spiral galaxy like our own Milky Way, then chances
are it has never been in such a collision. Yeah.
They think that the spiral galaxies used to dominate. I
(28:28):
think you said, like sixty of galaxies today are the
elliptical ones, right, the disordered ones, And they think that
spiral galaxies used to be the majority, but so many
of them merged to become elliptical galaxy galaxies. That's what
we see the most of now. Yeah. About what do
they say about fifty of all galaxies at some point
(28:48):
have been involved in a collision. Yeah, I saw as
high as ninety in one place, and the Milky Way
will at some point, right, Yeah, I mean there, it's
kind of inevitable, isn't it. We're going to emerge with
Andromeda and about five billion years. In about three billion years,
we'll are We'll start affecting one another at the edges,
will start pulling one another into each other, and then
(29:09):
we'll eventually merge and become one called the milk Ameda Galaxy.
Is that really what it's going to be called? Yeah,
hopefully within five billion years will come up with a
better name. Interesting um and drama see yeah, drama way
the the and drama way and drama way good, yea,
(29:31):
the androw way. It's definitely better than the milk Omeda. Yeah,
but I mean we're not gonna be around our show
will be I don't know, it's possible. What if this
lived on billions of years from now. That's I mean,
that's what we're doing, right, that's what we're hoping for.
So uh. These galaxies um throughout the universe do exist
(29:51):
in galactic clusters. They um they are drawn to one
another by gravity. And we are in um what called
a poor cluster, which is less than a thousand like
way less Yeah, called the local group, and there's only
fifty of us. That's a good local band name, too,
I think. So it sounds like sort of a union group, yeah,
(30:11):
or like the local forty one or whatever. If you're
just playing for free beer, that's that's what you're doing
with your band. Local groups should be the name of
your band. That's great, that's pretty good. Uh. And then
there are rich clusters, and there are more than a
thousand in the rich clusters, right, and some some have
way more than a thousand. There's one called the Virgo
supercluster that has of these of galaxies all clustered together.
(30:37):
So think about you've got a planets orbiting a star,
solar system. Solar system is orbiting the center of the galaxy.
Galaxies can orbit one another or at least have effects
on one another's orbits. Everything clusters together in larger and
larger amounts thanks to gravity. Once you pass a certain
(30:59):
threshold old and electromagnetism and the strong and weak nuclear
force or not like the dominant forces, gravity takes over
and it does some interesting stuff to the structure, and
it's driving astronomers batty. They're like, surely there is some
rhyme or reason to this. There's some pattern to the
there's gotta be there, like Jim Carrey in the number
twenty three or something, you know. Um, And they think
(31:23):
that if they can study the evolution of galaxies, they
will be able to figure out the process that happens
or what the ultimate point will be. Let's do let's
take a break. We got more things, all right. So
(32:01):
we've talked a lot about the distance between galaxies, but
there's actually a name for that space in between galaxies
and these clusters that we talked about, called the intergalactic medium.
And uh, it is not empty. It's not just some void. Uh,
And we don't know exactly what's going on in there,
but we're studying it a lot. Um. They think that
(32:21):
there's probably some gas, because I think that's the fault
for everything in space, Like there's got to be some
gas in there, and probably some dust, and a lot
of it's super cold like you would expect. Yeah, this
is what the strange thing is though, but some of
it is really really hot. And did have they explained
that yet? Now? No, they're just taking a step. It's
a really neat age of discovery for astronomy, Like we're
(32:44):
getting better and better at looking out into the universe,
so we're finding out more and more. But just just
because we get data back doesn't mean we can necessarily
make heads or tails of it. Yeah, but yeah, there's
there's hot sections of the inner interstellar void what's it
called intergalactic medium and the intergalactic medium, and um which
(33:05):
has kind of an interstilleroid. Sure, and but I can't
start making up astronomy terms. I need to use the
real one. Um. But there's also like in these hot pockets, right,
there's some pepperoni and cheese in there that will take
the roof clean off of your mouth. Um, there's hot
metals which would also burn the roof of your mouth
to a million degrees kelvin. Yeah, and I mean that
(33:28):
is the difference to um from the cold um intergalactic
medium about two degrees kelvin all the way to millions
of degrees. Yeah, that's quite a span. And no idea
why or what it's doing there, what's going to become
of it or if it used to be something else.
We just don't understand if it follows a pattern, and
it seems to yeah for sure. Um. And thanks to
(33:51):
Hubble too, we also have Hubble's law, which and it's
so hard to believe he was doing all this in
THEOD I know he was a boss. Yeah, like really really, Uh,
that's that's amazing. He also wants beat up James Webb
in a bar fight, which makes this whole telescope thing
really ironic. But Helpal's law states this observation that he
made way back when where and this is an actual
(34:14):
graph of this relationship. But he basically was like, you
know what, everything is moving away from us. Like every
time I look at something through this telescope, it's everything
is moving away and not only that, but the further
way it is, the faster it's moving away, which is
mind boggling. Yeah, because you can think, like, all right,
the universe is expanding, so that's fine, everything's moving away
(34:37):
from us. It also suggests that there's no center to
the universe. This is where that comes from, because everything,
no matter what direction you look in, it's moving away
from us. You would think that, but doesn't that mean
we're the center? Bite your tongue, um, But that's the
cosmological principle that everything is expanding the entire universe, not
(34:57):
everything in the universe is expanding within the uni the
very universe itself is expanded, right, And since some things
are moving away the further the further they are away,
the faster they're moving away from us, that means that
there's plenty of the universe that we will we can
never possibly detect, because if even if we get up
(35:19):
to the speed of light for travel, some parts of
the universe, the furthest away parts are actually spreading at
faster than the speed of light. So it is it
was cosmically impossible for us to ever detect a large
part of the universe, which is why when we're talking
about the universe that we're talking about and observing. That's
(35:40):
called the visible universe. But that's probably just a relatively
small chunk of the universe itself, which might be infinite
for all we know, and we may never know what
the universe is really shaped, like, what it's made of,
how big it is um because of this expansion that's
actually speeding up and accelerating beyond our our ability to detected. Amazing,
(36:01):
It's kind of sad in a way. Yeah, And eventually
this is this is the most mind blowing thing I've
ever heard. You're the expansion will accelerate so much that
the moon will no longer be visible to us, like
nothing will be visible to us. And on a long
enough time scale, I believe you wouldn't even be able
to detect your hand in front of your face if
(36:23):
you could, if it was physically possible, because of that
expansion of light. Right, So, the universe expanding is actually
pulling light out of its out of the visible spectrum
into a longer wavelength in what's called red shifting, because
the red is the longer wavelength end of the visible spectrum.
(36:44):
And so what Hubble did, what Hubble detected is called
the red shift. Everything's moving away from us. Yeah, which
we could observe because of X rays, right uh, because
the infrared I think, Yeah, man, I know I love
this stuff. Glad you do. I'm aroused. Oh goodness. Um So,
(37:07):
I guess if you're aroused, we should talk about active
galaxies because you know, I'm still waiting on my squeeze
by the way, Oh you're peanut squeeze all right, just
hang on. That's your little treat if we finished they
if we um. So, if you're looking at a normal galaxy,
(37:27):
let's say like the Milky Way, I guess all this
light or most of it that you're seeing UM is
pretty evenly distributed throughout that galaxy. Because it says, you know,
the same those same galaxies that have the even distribution
of light UM, they have looked at it through X
ray and ultra violet and infrared, and it seems like
(37:48):
they are giving off that energy from the nucleus. And
that is the active galaxy okay, yeah, which is a
very small percentage of the overall galaxy. Right. So the
light and energy in a normal galaxy and non active galley, see,
it's distributed evenly throughout, whereas in an active galaxy, all
of that light and energy is coming from the center. Yeah,
but they're I mean one of those like one how
(38:10):
I was gonna say one percent. I don't know if
I'm not you with the percentages, I know they're they're
fairly rare from what we actually I didn't have a percentage,
but it just has a very small percentage. Yeah, I
think they've they've discovered like a couple of thousands so far,
or less than less than half a million, less than
a million, which is a very small amount. But the
distinction between them and a regular galaxy is again, all
(38:32):
of that light, all of that energy is coming from
a very small portion of the galaxy rather than the
galaxy as a whole putting out all this light and energy.
This it's all concentrated in the middle. It's very weird.
And upon closer inspection, these things that look as bright
as you know, galaxies that are relatively close to us,
(38:52):
we're finding are actually billions and billions and billions of
miles light year I'm sorry, light years away from us.
But they seem just as bright. Makes them super energetic.
So they started to try to figure out what's going on,
and they think that the culprit are super massive black
holes at the center of these galaxies. Well, and that's
what it's at the center of our own. I suspect
(39:13):
there's a supermassive black hole at the center of every galaxy.
That's my big prediction for for the second decade, the
third decade of the century. We're going to figure that out. Okay, Um,
if you're talking active galaxies, there are four classifications within
that uh genre and uh they say that if it's
(39:34):
basically it may not be structural. It might depend more
on like the angle that we're viewing these things. Yeah,
like they're all probably the same thing, right, But for
that classification, it's the Seafort galaxies, radio galaxies, quasars and blazers. Yeah,
and radio galaxy. I only ran across here. Everybody else
just says it's Seafort, blazers and quasars. Yeah, radio galaxies
(39:57):
point oh one percent of all galaxies. So I think
freud Rinch has made that up. I think stock in
radio galaxies or something, so he slipped it in. That's funny. Um,
Carl Seafort coined the obviously in n the Seafort galaxies,
and um, what's the deal with these. So let's see,
(40:19):
the Seafort galaxy has no jets. So this is the
thing about an active galaxy, and this is why they
think there's a supermassive black hole at the center. They
think that the accretion disc of gas and dust and
everything that's just swirling circling the drain of the event
horizon of the black hole. UM. As this gas and
dust circles, friction develops, speed develops, and it gets so
(40:43):
hot that some of that material doesn't get stuck in
the black hole instead gets shot away above and below
the black hole into jets that are so tall they're
as tall as the galaxy is wide. They're just huge,
huge energetic fountains of of just basically pure energy and
(41:06):
um that's what causes this brightness that can be seen
from so far away and depending on the angle of
it relative to us, we've basically said it's a Seafort galaxy,
which means that we're probably seeing it from the side,
and so we can't see the jets because they're not
pointed to us. And then there's blazars and quasars too,
and in the case of the blaze, are that's looking
basically straight on it that jet that you were talking
(41:28):
about coming right at you, right at your face, looking
down the barrel of a blazer. And then the quasars. Uh,
we discovered those in the nineteen sixties. Um, they've discovered
what like thirteen thousand, but they think there could be
up to a hundred thousand. And these are billions of
light years away from us, and these are the ones
that are the most energetic of them all. Yeah. So
(41:49):
if you look at a quasar something like that and
the jets coming out of the quasar, what you're actually
seeing is basically the most potent particle accelerator in the universe,
just shooting those energetic particles into space. It's amazing. I
can't imagine what it would be like to be anywhere
near something like that. You die, yeah, but it's like
(42:11):
you were just there in spirit or something, you know.
Or if you could see it with a space telescope,
that'd be great too. I'd settle for that for the
James the James Woods space telecop What else you got? Oh,
the Starburst galaxy thing at the end was kind of interesting. Yeah. This, Um,
I just want to go on record is saying Starburst
(42:32):
is one of the most beautiful words ever. You like that,
I love it. Yeah, I like that too. Attached star
or burst onto anything. Well, that's not true, because a
fecal burst, fecal first star that sounds prettier than fecal burst,
a fecal star, I sure, I guess. Yeah, it's just
about everything sounds better than fecal burst. So um galaxy says,
(42:57):
we know them have a very low rate of new
star ours being formed, usually about one a year, but
the star Wars galaxies produce more than a hundred a year,
which is amazing. Yeah, it is compared to the rest,
hundred times more amazing than a regular galaxy. That's true.
They also think that they burn themselves out rather quickly,
and that those might actually be the globular clusters that
(43:19):
end up just kind of hanging around a real galaxy. Well,
they say, the stars that burn the brightest. Yeah, like
Jimi Hendrix. Yeah, the Seven Club, all globular clusters, starburst.
That's it. That's it. If you want them more about galaxies, friends,
there is a whole universe out there for you to
(43:40):
go check out, and you can start on the internet,
So go check it out there. Uh. And since I
said something weird like that, it's time for listener mail.
So in lieu of listener mail, okay, we uh, we
got a lot of feedback on our stalker episode, which
kudos to you, that's your idea, and they ended up
(44:01):
being a really good episode, I think. Um, but we
got a lot of emails from um, both men and
women who had been victims of stalking. Some people who
didn't even know they've been stocked until they listen to
the episode you're like, oh, okay, I was stalked. Yeah,
and some really just heartbreaking, scary, scary, in depth, long
stories and we heard people who had to move and
(44:22):
we're still in the midst of it. It's just awful.
It's tough stuff. So we're not gonna read any of
those because they are very personal stories and um, they're
all anonymous, yeah, most most of them were. UM, but
we just want to say thanks to everyone for being
brave enough to share your story with us and just
direct people to get help if you're being stalked. Uh.
(44:43):
It is serious stuff and I hope that podcast really
got that across. Yeah, And that was one thing almost
universally that we heard was that like, thank you for
saying like go find local help because it's out there,
and that's a huge first step. Yeah, and a lot
of these people, like just like we had talked about,
kind of went through the batim steps of people at
work thought I was just overreacting, and even my family
(45:05):
thought I was blowing it out of proportion. Why didn't
you press charges the first time? Do you wait for?
You know that? Yeah, blaming the victim, basically all that stuff. So, uh,
you can reach out to the Stalking Resource Center, the
National Center for Victims of Crime. It's a good place
to start. Um. There are plenty of it. Depending on
what country you're from. There are different organizations to see
(45:26):
one from the UK where you can report a stalker
um and in fact, one of our listeners from the
UK had a really hard time over there being taken seriously. Uh.
And then there's also rain are AI n N who
is in their twenty fi year and they have some
good resources for you as well, So just check it
(45:46):
out online. Nice work, Chuck, Nice work, Josh. All right, Well,
thank you everybody who wrote in, And if you want
to write in for a new reason, you can go
to our website at stuff you Should Know dot com
and check out the social links. I have a website
to d Josh Clarkway dot com and you can send
us all an email me, Chuck, Jerry, Everybody to Stuff
(46:06):
podcast at how stuff works dot com. For more on
this and thousands of other topics, visit how stuff works
dot com. M
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Josh Clark
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