0:00

So the King's new lemonade lineup

0:03

is here. Name and a lemonade

0:05

The Smoothie King Way try strawberry.

0:07

Guava Lemonade ask refresher over

0:09

ice a power up in

0:12

it can energize, or a

0:14

blueberry lemonade smoothie lead it

0:16

up being. Made

0:18

with real fruit. Real juice for

0:21

a real sipping good summer. Yeah

0:23

yeah, Data is no Smoothie Kings

0:25

New lemonade lineup of for a

0:27

limited time. Who. Stars Day.

0:34

Sometimes I just want

0:37

to unleash my inner eight year

0:39

old and destroy

0:41

something. Just pick it up

0:44

and smash it. Maybe to

0:46

see what it looks like on the inside. Maybe

0:48

to see how it works. Maybe just because

0:50

I feel like it. And

0:52

that's valid enough reason. So

0:55

since I'm in a smashing mood today, I

0:57

thought it would be fun to destroy a

1:00

galaxy. That's

1:03

right, a galaxy. I mean, if we're

1:05

going to destroy something, we might as

1:07

well go big, right? And we've blown

1:09

up stars and dismantled planets before in

1:11

previous episodes. So that's no fun anymore.

1:13

We're going to do everything we can to

1:16

fully, and I mean totally

1:18

and completely and utterly, destroy

1:21

a galaxy. As

1:23

you know, galaxies are kind of large and

1:25

kind of complex places. A typical galaxy will

1:27

be home to anywhere from 100 million

1:30

stars on the small side to trillions

1:32

of stars on the large side. Our

1:35

own Milky Way galaxy has about 300 to

1:38

500 billion stars, while

1:41

our neighbor Andromeda has around a trillion.

1:44

Galaxies have a range of sizes. The smallest

1:46

ones are hard to distinguish from dwarf galaxies,

1:48

which deserve an episode in their own right.

1:51

Go ahead and ask. So

1:53

we'll go ahead and put ranges anywhere from

1:55

10 ish thousand light years across

1:58

to up. few

2:00

hundred thousand light years across on the

2:02

side for anything for galaxy scale. They

2:05

come in all sorts of shapes in

2:08

addition to all sorts of sizes. In

2:10

addition to all sorts of sizes,

2:12

they also come in all sorts of

2:14

different shapes. You have the beautiful spirals,

2:17

the boring ellipticals, the uglier regulars, but

2:20

a galaxy beauty contest is, as you

2:22

guessed it, another episode because today we

2:25

are focused on smashing. But

2:28

if we're going to destroy a galaxy, we're

2:30

going to have to contend with more than

2:32

just stars. I mean, stars are great and

2:35

all. I even have a favorite one. But

2:37

altogether, they make up only a few percent

2:39

of the mass of a typical galaxy. You

2:42

heard me right. When you see something

2:44

grand and beautiful, like the Andromeda galaxy

2:46

and all of its spirally glory in

2:48

front of you, you're looking

2:50

at less than a few

2:52

bits out of a hundred of the

2:55

true contents of the galaxy. About

2:57

10% of a galaxy is just

2:59

loose bags of gas and dust just

3:01

floating around, minding their own business, not

3:03

bothering anybody and not being bothered by

3:05

anything. There are stellar remnants like the

3:07

white dwarfs and the black holes. There

3:09

are the brown dwarfs. There

3:11

are a bunch of other things like planets that don't really

3:13

add to the total. And the

3:16

rest is all dark matter. You know,

3:18

this invisible form of matter that suffuses

3:20

every galaxy and actually overwhelms every galaxy.

3:23

When you look at a galaxy, you're

3:25

just seeing the center concentration

3:27

of matter. It's enveloped in

3:29

something we call a halo,

3:31

this gigantic ball of dark

3:33

matter. So how do

3:36

we go about destroying something as

3:38

grand and beautiful and seemingly permanent

3:40

as a galaxy? The first galaxies appeared

3:43

over 10 billion years ago, and they

3:45

tend to stick around. So they seem

3:47

like rather hardy creatures in the universe.

3:50

If we're going to destroy a galaxy, we

3:52

need a source of energy. We need something

3:54

to power our endeavors and make this happen.

3:57

The good news is that the universe is

3:59

full of all sorts of sources of energy

4:02

and there's plenty enough energy to go around

4:04

to rip a galaxy to shreds. And as

4:06

we survey the possible avenues we

4:09

can take to destroy a galaxy like a

4:11

toy we don't care about anymore, we're

4:13

going to rate this on a

4:15

satisfaction scale with the amount of satisfaction

4:18

proportional to the amount of destruction that

4:20

we can achieve. So let's

4:22

see what our options are. Number

4:24

one, I know, I know

4:27

a giant black hole. Now giant

4:29

black holes are large. Supermassive

4:31

black holes are a few million times the

4:33

mass of the sun all the way up

4:35

to hundreds of billions of times more massive

4:37

than the sun. Almost every

4:40

single galaxy hosts a supermassive black hole in

4:42

its center. The Milky Way has one we

4:44

call it Sagittarius, a star. The star is

4:47

an asterisk, by the way, the different

4:49

different episode. It's

4:52

about four and a half million times the mass of

4:54

the sun, which is gigantic. These supermassive black holes are

4:58

almost always the largest

5:00

single object in a

5:02

galaxy. And yet compared to the total

5:05

mass of a galaxy, especially including all

5:07

the dark matter, they're like less than

5:09

one percent of the total mass of

5:11

a galaxy. So by mass they don't

5:13

do much. By size they

5:16

don't do much either. Supermassive

5:18

black hole, just

5:21

to have a picture in your head,

5:23

just think solar system scales like maybe

5:25

Mercury orbit, maybe Pluto orbit, maybe even

5:28

larger orbit, but just somewhere in the

5:30

vicinity of the size of a solar

5:32

system is the typical size of the

5:34

event horizon of one of these giant

5:36

black holes. So by

5:38

mass they're not influential. By size

5:41

they're not influential, but they

5:43

are one of the most

5:45

important aspects of a galaxy,

5:48

and that's because of their

5:51

enormous gravity. When matter

5:53

falls into a black hole, say

5:55

a star gets torn to shreds, or

5:57

there's a giant clump of gas that

5:59

gets too close. It gets caught

6:01

in the gravitational grip of the

6:04

black hole, and then it flows

6:06

inwards. And as it does, that

6:08

gas compresses. It has to squeeze

6:10

a whole giant volume

6:12

of material down into a relatively tiny

6:14

space. And yes, I know we're talking

6:16

about objects the size of solar systems,

6:18

but for galaxies, that's a tiny space.

6:21

This material heats up. It compresses,

6:24

heats up, and emits radiation. This

6:26

radiation then blasts out through the

6:28

rest of the galaxy during one

6:30

of these feeding episodes. It's in

6:32

this phase that we call the

6:34

material surrounding a black hole. We

6:36

call it a quasar. These

6:39

things are the most

6:41

energetic long-term events in the entire

6:43

universe. You can have brief events

6:46

like a gamma ray burst or

6:48

a hypernova that can briefly put

6:50

out more energy than a quasar,

6:53

but not over long periods of time. A

6:56

gamma ray burst will last like two seconds.

7:00

A giant flash of flare from a

7:02

magnetar or something will last like a

7:04

microsecond. These things are nothing. Supernova

7:06

will be bright for a couple

7:09

weeks. A quasar can

7:11

outshine a million galaxies at once, and

7:14

they can last for millions of

7:16

years. They are insanely energetic, the

7:18

most powerful engines in the entire

7:20

universe. And what this

7:22

energy does is when

7:24

it goes out of control, it can kill a

7:26

galaxy. It kills a galaxy by

7:29

heating up all the gas. The gas in

7:31

a galaxy, this random collection of gas and

7:33

dust that's just floating around, if it wants

7:35

to make stars, that gas has

7:38

to cool off. It has to compress.

7:40

It has to reach very, very high

7:42

densities. It can only do that by

7:44

releasing heat. It has to cool off

7:46

and compress, and then you get star

7:49

formation. But if you have these quasars

7:51

like blasting radiation out, it heats up

7:53

all the gas, and it

7:55

shuts off star formation. In

7:58

worst case scenarios, we have some a

16:00

few hundred million years, we'll be brilliant, we'll

16:02

be intense, we'll have so many

16:04

stars, it will look amazing. And

16:07

then we'll go to make new stars and there

16:09

won't be any gas left in the tank. The

16:12

black holes merge. There's

16:14

a new round of quasar activity

16:16

which will strip material away. The

16:18

merger itself will scatter material. Patreon

16:21

will shut down. That's patreon.com/PMSutter. It's

16:23

how you keep this show going.

16:26

And we are going to keep

16:28

this show going. All

16:31

the way, at least until the merger of

16:34

Andromeda and Milky Way five billion years from now.

16:38

And we need, I need your help to

16:40

keep that going. That's

16:42

patreon.com/PMSutter. On

16:45

the satisfaction scale, I'm going to give galaxy

16:47

mergers a three out of five. It's

16:50

fun for a while and there are some fireworks. It's

16:53

exciting. Black holes merging, quasars activating, black

16:57

holes, star formation, out the

16:59

wazoo. It's crazy, but then it just kind of

17:01

fades away. And then you're left with a

17:04

lump of mixed up galaxy

17:07

that just kind of sits there. Doesn't

17:09

quite get the job done. Okay,

17:11

that's major mergers. What

17:15

about minor mergers? Like

17:18

taking a small toy and

17:20

smashing it up against a big toy.

17:23

See the key here is we can't rely

17:25

on galaxy clusters because they're

17:28

too thin. We can't rely on any

17:30

internal mechanisms because they're not powerful enough.

17:33

Smashing one toy against another

17:35

toy galaxies, they just

17:37

don't have the right kinds of stuff to

17:39

make this interesting. But what if I take

17:42

a small galaxy and smash it against a

17:44

big galaxy? Well, we

17:46

know what happens. We

17:49

never get to observe galaxy mergers play

17:51

out in real time. Like I said,

17:53

these things take hundreds of millions of

17:55

years to play out for the process

17:58

to unfold. So we don't. Instead,

22:00

when we make a plot

22:02

of velocity, inward

22:06

and outward, we call that radial velocity,

22:08

and then velocity along the line of

22:10

sight, there's this like, you get all

22:13

sorts of stars with these kinds of

22:15

velocities in different directions. And then you

22:17

get this lump sitting out

22:19

here, we call that the Gaia sausage. I'm

22:23

sorry. It's just what

22:25

we call it. The people who

22:27

came up with it thought it was a good idea at the time.

22:31

The Gaia sausage is the remnant

22:35

of a smaller galaxy that collided with

22:37

the Milky Way and was totally destroyed

22:39

by it billions of years ago. It's

22:42

not obvious. It's not a clump

22:44

anymore. But

22:46

all the stars in the

22:48

Gaia sausage have similar metallicity,

22:50

similar ages, similar orbits, similar

22:52

velocities. Radially

22:54

means similar velocity

22:57

going inwards or outwards relative to

22:59

the center of the galaxy, similar

23:01

velocities going across our line

23:03

of sight. They

23:05

stick out. This is a remnant

23:07

of a galaxy that collided with ours

23:10

billions of years ago, and that galaxy

23:12

was destroyed. It was

23:14

torn to shreds by the

23:16

gravitational might of the Milky Way. Its

23:19

stars were dispersed throughout

23:21

the Milky Way. We

23:23

can only find the remnants through this detective

23:25

work by going

23:28

to galaxyancestory.com and

23:30

figuring out that we all share, like

23:33

these stars share the same DNA sequence.

23:36

But it was a galaxy. It was a dwarf galaxy, but

23:39

still a galaxy that was

23:41

destroyed and cannibalized and incorporated

23:43

into the Milky Way. The dark matter

23:46

component is just now

23:48

mixed up with the Milky Way,

23:51

indistinguishable. There might be a Gaia

23:54

sausage dark matter particle that

23:56

was one time a member of a different

23:58

galaxy. and then got mixed up with the

24:00

Milky Way that's passing through you right now.

24:03

There are other associations, other streams,

24:05

other collections. Sometimes we can actually

24:08

see the physical stream of stars.

24:10

They're not fully dispersed. They're not fully mixed

24:13

in with the Milky Way. There's

24:15

the Archeron stream, the Styx stream,

24:18

Lemost one, Spectre, many more. These

24:20

ghostly tenuous remnants of

24:23

galaxies. Some of them are

24:26

still hanging on, still have

24:28

some semblance of existence and some

24:30

that are totally,

24:34

totally destroyed. So satisfaction

24:36

scale, five out of

24:38

five, maximum gore, maximum

24:40

destruction. We are taking a

24:42

small toy, smashing it into a

24:44

larger one, and the pieces

24:47

are so small now, that it's

24:49

hard to tell they were even

24:51

a part of a toy to

24:53

begin with, a separate toy altogether. That

24:56

is that's peak satisfaction. There

24:58

is one more option though, and

25:01

that option is to wait. And

25:03

folks, we need to take a

25:05

brief break because I need to mention

25:08

that this show is sponsored by BetterHelp.

25:10

And I want to

25:12

talk about comparison. They

25:14

say that comparison is the thief of joy, and

25:16

that is so true. I

25:19

have spent so many years in my life

25:21

in a hyper competitive

25:24

environment, academic research is

25:26

beyond competitive. You're constantly

25:28

comparing yourself. Oh, they're doing better research,

25:30

they're publishing more papers, they give a

25:32

better talk or they have a better

25:34

tie than me. It's like, and you

25:36

just sink yourself lower and lower and

25:38

lower because you constantly compare another

25:40

person's best to your

25:42

internal worst. And that

25:45

is so damaging. It is one of

25:47

the hardest things to overcome. So

25:51

the way I went around

25:53

that and I worked with my own therapist

25:55

to develop these kinds of skills and tools

25:58

was not to was to keep. comparing

26:01

myself to others, but to compare myself to

26:03

my past self. What was

26:05

old Paul doing 10 years ago, five

26:08

years ago, last week? Am I a

26:10

better person? Am I more kind and

26:12

giving? Am I more

26:15

generous? Am I

26:17

more successful in my career? Am I having more

26:19

fun in my career, in my job, in my

26:21

daily life than I was last week, a year

26:24

ago, 10 years ago, 20 years ago? And

26:27

if the answer is yes, then I'm

26:29

winning. I'm winning the game of life. And the

26:31

only competition is me. It's like when you play

26:34

a racing game and you're fighting the

26:36

ghost car of your previous best

26:38

lap. That's the comparison that

26:40

I like to make. And

26:42

therapy helped guide me to that

26:44

conclusion. If you're thinking of starting

26:46

therapy, give better help. Try. It's

26:49

all online, designed to be convenient, flexible, suited

26:51

to your schedule. Fill out a

26:53

brief questionnaire and you're good to go. Stop

26:56

comparing and start focusing

26:58

with better help. Visit

27:00

betterhelp.com/spaceman today to

27:02

get 10% off

27:05

your first month.

27:08

That's betterhelp, help.com/spaceman.

27:13

Galaxies are survivors. Milky

27:16

Way galaxy has been around for what,

27:18

11 billion years now. It's

27:22

cannibalized and destroyed many other galaxies. It

27:24

will merge with Andromeda and it, but

27:26

it will still be an object after

27:28

that. It'll just have a new name.

27:31

Some people have proposed Milk-O-Mida. I

27:33

hate that, but

27:35

we'll, we'll save that for a later discussion. We

27:37

have a few billion years to

27:40

decide that one, but

27:42

it will still be a galaxy. It will still exist.

27:46

But if we wait long enough, I

27:49

mean the universe has only been around for 13.8 billion years. What

27:52

if we wait a hundred billion years, a

27:55

trillion years, a hundred trillion years, some

27:57

measure of time that would put the.

28:00

make the current age of

28:02

the universe peanuts insignificant. Well,

28:05

when you're willing to wait an extremely

28:08

long time, interesting things start happening. Gravity

28:11

starts to do its work. You

28:13

know, a galaxy is mostly empty

28:15

space, but sometimes

28:17

stars get close to each other. They

28:19

interact briefly. Maybe they collide

28:21

and they destroy each other. Maybe they just

28:24

pass close by and they swing past

28:27

each other and there's a slingshot and

28:29

in exchange of energy, one

28:31

of those stars gets to stick around and

28:33

one of those stars gets ejected from the

28:35

galaxy. We see this, we call them hypervelocity

28:37

stars. These are stars that have

28:39

been ejected from their host galaxy. It

28:42

happens all the time. It's rare, but

28:44

it happens. Give yourself a hundred trillion

28:47

years. It happens to a lot. Eventually,

28:50

all stars

28:52

in a galaxy will either be scattered

28:54

away or scattered

28:57

into the supermassive black hole at the center.

29:01

As for everything else, like planets, well,

29:04

with enough time, they will just

29:06

dissolve through quantum mechanical tunneling. Eventually,

29:10

all bound structures will evaporate

29:13

given timescales of

29:15

hundreds of trillions of years. All

29:18

macroscopic objects just dissolve, evaporate,

29:22

expand away from each other, get caught up in

29:24

the expansion of the universe. And

29:27

that is a sure fired way to destroy a

29:29

galaxy. As a satisfaction scale, I'll put that four

29:32

out of five. It's

29:34

incredibly slow, incredibly

29:37

agonizing, but you do completely

29:39

and totally destroy any

29:42

semblance of

29:44

a galaxy. Like even the Gaia sausage

29:46

still maintains some of an identity. They've

29:49

been, the Gaia sausage immigrated

29:52

into the Milky Way. They've

29:54

assimilated. They've picked up

29:56

all the culture and habits

29:58

and norms. They celebrate this. same

30:01

holidays as all the

30:03

Milky Way natives,

30:06

but they still have that genetic heritage

30:09

that gives them away,

30:11

that signals that they came from

30:13

somewhere else. But if

30:16

you wait long enough, all

30:18

distinction is gone. All the stars

30:21

are there ejected or consumed,

30:24

even the individual particles that make up

30:27

planets and asteroids and comets and all

30:30

that dissolve, float away. Even

30:32

black holes evaporate after something like 10 to 100 years.

30:35

Hawking radiation will guarantee that the black

30:37

holes evaporate and there's nothing left.

30:40

And so the only way to

30:43

completely and totally eradicate a

30:46

galaxy to erase it from

30:48

existence is to wait

30:50

an extremely long time. But if we're channeling

30:52

our inner eight year old, that's

30:55

way too much time. Hence

30:57

the satisfaction scale of four out of five.

30:59

My favorite way, the winner for

31:02

me is to smash a small galaxy

31:04

against a larger galaxy that would

31:07

be most satisfying to my inner eight

31:09

year old. Thank you to Michael, Cian

31:11

email and Steven D on Facebook for

31:13

the questions that led to today's episode.

31:15

And thank you to all my Patreon

31:18

contributors. All of you are doing so

31:20

much amazing things. Every contribution

31:22

counts. All of it supports the show. All of

31:24

it keeps the show going. I can't thank you

31:26

enough. I would

31:28

like to thank my top contributors this month.

31:32

They are Justin G Chris L,

31:34

Alberto M, Duncan M, Corey D,

31:36

Stargazer Robert B, Tom G, Nyla,

31:38

Sam R, John S, Joshua

31:40

Scott M, Rob H, Scott M,

31:42

Lewis M, John W, Alexis Gilbert

31:44

M, Rob W, Dennis A, Jules

31:46

R, Mike G, Jim L,

31:48

Scott J, David S, William W, Scott R, B,

31:50

C, C, C, B, J, J, 108, Heather,

31:53

Mike S, Michelle R, Pete

31:55

H, Steve S, Watt Watt

31:57

Bird, Lisa R, and Kuzi.

32:00

Thank you so much, everyone, for your

32:02

contributions. Thank you for the amazing questions

32:04

that you're always sending me. Keep them

32:06

coming. That's askaspaceman.com

32:08

or askaspaceman@gmail.com. Send me

32:10

those questions. I'll put them

32:13

on the list someday, hopefully before

32:15

the Milky Way dissolves. I

32:18

will get to it, and I will see you next

32:20

time for more complete knowledge of time and

32:22

space. So

32:55

the King's new lemonade lineup is

32:57

here. Name and a lemonade The

33:00

Smoothie King Way try strawberry. Guava

33:02

Lemonade ask refresher over ice

33:04

a power up in it

33:06

can energize, or a blueberry

33:09

lemonade smoothie lead it up

33:11

being. Made with

33:13

real fruit. Real juice for a

33:15

real sipping good summer. Yeah yeah,

33:18

Data is no Smoothie Kings New

33:20

lemonade lineup of for a limited

33:22

time. Who. Stars Day. thirsty?