0:00

What is the most distant object we can

0:02

see in the solar system? Do

0:05

satellites collide? And how

0:07

come we have pictures of the Milky Way? All

0:10

this and more in this week's question

0:12

show. Welcome to the

0:14

question show. Your questions, my answers. As always, wherever

0:16

you are across my channel, the question pops in

0:18

your brain. Just write it down and I will

0:20

gather them up and I will answer them here.

0:23

Alright, let's get into the questions. Thomas

0:25

clues a 3 663. What

0:28

is the most far away object currently observed going

0:30

on the sun within the solar system, which has

0:33

a distinct name and how far is it? What

0:36

telescope or spacecraft observatory has found it

0:38

and was it the actual limit? Astronomers

0:40

have discovered many objects in the outer solar

0:43

system out in the Kuiper belt that I

0:45

think are going to meet your needs. So

0:48

I'm just going to give you like the direct answer to this. And

0:51

that is the most distant object in the

0:53

solar system that's ever been seen by astronomers

0:55

is an object named 2018 AG 37. And

1:01

its nickname is called far far out.

1:05

And it's named because there was another object

1:07

called far out that was thought to be

1:09

the most distant object and then far far

1:11

out superseded that. And so now that is

1:13

an old system object that we know of.

1:15

And I guess now this is the rule.

1:18

And so when the next object is found, it has to be called

1:20

far far far out and we just keep adding far as forever.

1:24

So far far out was

1:26

observed at one hundred and

1:29

thirty two astronomical units. And

1:32

just for comparison, Pluto is at about

1:34

50 astronomical units. So it

1:36

is much farther than Pluto and

1:38

it's not a small object. It is probably

1:41

in the dwarf planet class. It's

1:44

a object about 400 kilometers across. So

1:47

it's probably going to be roughly

1:49

spherical and is a pretty

1:52

substantial object. Now,

1:55

it was found using the Subaru telescope. And

1:57

this is an eight point two meter telescope that's located in the north.

2:00

on Hawaii. It's only

2:02

been observed about nine times in

2:04

the entire history that astronomers have

2:07

known about it. And so far,

2:09

that record has yet to be

2:11

beaten, but it will be destroyed

2:14

when Vera Rubin comes online next

2:16

year. So to stay

2:18

tuned for that when we just suddenly have

2:20

just an enormous number of new objects that

2:22

have been found. Now, that's it. I

2:25

want to sort of talk about a couple of other

2:27

kinds of objects that are similar and are interesting. in

2:30

their own ways. So one is

2:32

the dwarf planet Sedna. And this

2:34

is an object that would be

2:37

the most distant object. If

2:39

it was at the farthest point in its orbit,

2:41

because it is on a

2:43

10,000 year orbit that brings it between

2:46

about 76 astronomical

2:48

units. So, you know, about 50% farther away than

2:50

Pluto, but then goes all the way out to

2:53

almost 1000 astronomical units does this big long elliptical

2:55

orbit and astronomers found it as they And

2:58

astronomers found it as it's approaching that

3:00

closest point. So it's the fluke that

3:02

was found on that 10,000 year

3:05

orbit. But these are

3:07

nothing compared to the

3:09

long period comets that we

3:12

see falling into the

3:14

solar system. These are on orbits

3:16

that take 30 million

3:19

years or more. And

3:21

so the most distant long period comet has

3:23

ever been seen probably has, like, a

3:27

great assistance from the sun is

3:29

about point four light years. And

3:32

so it just just falling into the

3:34

solar system for hundreds of thousands, millions

3:37

of years until it finally passed by

3:39

the sun for the first time, or

3:41

sometimes he just fall directly into the

3:43

sun. And that's that, which is

3:45

kind of depressing. And so this

3:47

word cloud is thought to go about halfway to the

3:50

closest star. And there's almost certainly going to be large

3:52

objects that are going to be out there in that

3:54

or cloud. So, you know, what is the most distant?

4:00

an object in the solar system, we

4:02

have no idea. We will never know.

4:04

Now you might have noticed the Star Trek planet

4:06

name that appeared above my shoulder. This is a way

4:08

for you to vote for you to tell us what

4:10

you thought was the most fancy

4:13

striking question of the week.

4:16

And so the winner this week was for

4:18

Ryan about dark matter. Is it

4:20

only observed at the farthest reach of the

4:22

universe or is there dark matter closer? So

4:24

thank you, Ryan for asking the question. Thanks

4:26

everybody for voting. Now we're going to give

4:28

a different Star Trek planet name beside each

4:30

one of the questions this week. We'll

4:33

put a list of them down in the show us down below

4:35

as well as the chapter markers. And so just when

4:37

you post a question or a comment

4:39

or anything, just include the code word

4:42

for the planet name for the question that you thought was the

4:44

best. And then we will count them

4:46

up. And we will celebrate that here. Jared

4:49

T brush, why don't satellites ever collide? Is there

4:51

a public place to know the directions of satellites?

4:53

What if I want to put a satellite into

4:55

space and not telling what direction is that illegal?

4:58

Who says satellites don't collide satellites

5:00

have collided. In fact, you know,

5:03

less than 10 satellite collisions have

5:05

been found in space

5:07

so far. And

5:10

you know, there's been a couple of

5:12

high profile collisions, probably the most famous

5:14

one was in 2009. And

5:16

a radian satellite, this

5:19

was a telecommunications satellite fully functional

5:21

was smashed into by a

5:23

Russian Cosmos 2251 satellite. And this

5:25

one was in operational as

5:29

a piece of space junk and smashed

5:31

into the radium satellite, destroyed

5:34

it and generated

5:37

1000s of pieces of debris. And in fact,

5:39

the space tracking agencies

5:42

are still tracking hundreds

5:44

of pieces of debris. But it was thought

5:46

that there was like, you know, about 2000

5:48

pieces of debris that were larger than several

5:51

centimeters across. So it

5:53

was pretty significant. And in fact, it was so significant

5:56

that one of the pieces

5:58

of debris came so close to the International

6:00

Space Station came within about 120 meters

6:02

of the International Space Station, that the astronauts

6:05

on board had to go and hide in

6:07

the Soyuz capsule and be ready to evacuate

6:09

if the debris actually got close to that.

6:11

And there are times when ISS has to

6:14

change its orbit slightly because there's a piece

6:16

of space debris or there's a warning. And

6:19

you know, it's believed that every day,

6:21

several satellites come within a kilometer of

6:23

each other. But they probably come a

6:25

lot closer than that. You know, people

6:27

have seen instances of satellites coming within

6:29

10s of meters of each

6:31

other. And this problem

6:34

is just going to get worse as there are more

6:36

satellites launching to space, there's more chances of these close

6:39

flybys. Now your question

6:41

was, you know, is a

6:43

public policy of the directions of satellites? Yeah, there's

6:45

a bunch of online websites that

6:47

you can go to be able

6:50

to track the positions of

6:53

various satellites. So the

6:55

one that I like is heavens above, they've

6:57

got like really prominent locations

6:59

for the International Space Station, as

7:01

well as various spacecraft that are

7:03

launched, Hubble Space Telescope, things like

7:05

that. But they've got data for

7:08

as many satellites as you can possibly imagine.

7:10

And you can just go and see, you

7:13

know, it'll show you like where you are. And you

7:15

see all the satellites are going to be flying overhead.

7:17

In many cases, you know, if you go outside and

7:19

you see a satellite flying overhead, you can go back

7:22

and look at heavens above. And you can know what

7:24

that satellite was. For the third

7:26

part of your question, what if you

7:28

want to put a satellite into space and not tell anyone is

7:30

that illegal? Well, you can't because you have to

7:32

launch the satellite. And so you're going to launch

7:34

the satellite on a SpaceX rocket, you're going to

7:36

launch it on a Russian rocket, you're going to

7:38

launch it on a Chinese rocket. It's

7:41

obvious that you have launched that rocket. And

7:43

there are many people that are tracking the

7:45

launches of rockets for obvious reasons. And

7:48

so then the direction

7:50

and trajectory of your satellite is then

7:53

very well known. Now, are there any

7:55

rules to stop you from launching your

7:57

rocket? And the answer is not

8:00

internationally. So there are going to be rules

8:02

for a specific country. Like if you are

8:05

a US citizen, and you want to launch

8:07

it on a US rocket, there

8:09

are rules, you can't just launch

8:12

it willy nilly, you can't just

8:14

have it broadcasting across different spectra,

8:17

you've got to, you know, there

8:19

are various rules that you have to be

8:21

willing to adhere to. But there are no

8:23

international rules that absolutely define where

8:26

you have to launch your satellite to and

8:28

so and this is a big problem, right?

8:30

Like, like, because we have no international regulations

8:32

that define where satellites should be launched, what

8:34

kinds of orbits that use, we have this

8:36

problem of space junk, we have this problem

8:38

satellites that are getting really close to each

8:40

other. So hopefully, someone

8:43

will solve this problem, there will be an

8:45

international agreement that will come together, and

8:48

we'll define where satellites are allowed to

8:50

be launched, like the

8:52

way airplanes fly along corridors,

8:54

the way boats sail

8:56

along corridors, so they don't collide with each

8:58

other. We need that for space. pissed

9:01

off Kristoff, where do pictures of

9:03

the Milky Way come from? One of

9:05

my favorite things to take pictures of

9:07

is the Milky Way. And you can absolutely

9:10

take images of the Milky Way. All you

9:12

have to do is go out in a

9:14

place with relatively dark skies, and

9:16

take a long exposure image with

9:19

your DSLR camera, even like modern smartphones

9:21

can do this now, I have a

9:23

pixel six and has a really good

9:25

astrophotography mode, if you put it into

9:28

a mode where

9:30

if you put it on a tripod, and so

9:33

it remains really still, then it will shift into

9:35

astrophotography mode, and it will take a pretty good

9:37

image of the Milky Way that'll show you the

9:39

dust lanes and that now obviously, we are

9:41

trapped inside the Milky Way. And so all

9:44

of the images that you're going to see

9:46

of the Milky Way were taken from planet

9:48

Earth, this is the only place that we can

9:50

actually take images of the Milky Way. And yet,

9:53

obviously, you know, we have seen images of what

9:55

the Milky Way looks like. And

9:57

the reality is that we don't know exactly

9:59

what the key way looks like because we're inside.

10:01

It is equivalent of you not knowing what the outside

10:03

of your house looks like if you're inside your house.

10:05

Now, but you could get glimpses, right? Imagine cars driving

10:07

past, you could see a little reflection off the window

10:09

as a car goes past, you get a little bit

10:11

of an idea like, Oh, the outside of my house

10:13

is blue. Okay. All right, I'm going to paint my

10:15

house blue. And I sort of know the shape of

10:18

the house from the inside. So I can probably guess

10:20

what the shape of the house of the outside is,

10:22

but I don't really know what's siding and all that

10:24

kind of stuff. And

10:26

so we have ways of

10:28

being able to measure the rough structure

10:30

of the Milky Way. And there's a

10:33

couple of really useful tools. One is

10:35

pulsar. So these are dead stars, neutron

10:37

stars that are spinning really

10:39

rapidly. They're putting out pulses, and we

10:41

can see them for a very long

10:44

distance away across the Milky Way. And

10:46

if you observe enough of these pulsars,

10:48

these beacons, you start to get this

10:50

sense of what is the larger structure

10:53

of the Milky Way. And then we

10:55

have missions like Gaia, which

10:57

are tracking the location and direction

10:59

of billions of

11:01

stars in the Milky Way. And so in

11:03

that, we are able to just get this

11:06

sense of what is the nearby structure of

11:08

the Milky Way and sense some of its

11:10

larger structures like does it have a bar

11:12

at the center? Does it have two

11:14

spiral arms, four spiral arms, things like

11:16

that. And then when you've

11:19

sort of got this rough sense of what

11:21

the Milky Way probably looks like, well, then

11:23

we've got a universe of other examples of

11:25

spiral galaxies that we can look at, and

11:28

then try to compare what we know about the

11:30

Milky Way to what's out there. And

11:32

you can just shop around until you find

11:35

a galaxy that is nicely face on. That

11:37

is a really good model of what our

11:39

Milky Way looks like. And plenty of these

11:41

examples, you'll see images from the

11:43

Hubble Space Telescope where you've got a galaxy

11:45

that is a face on spiral and astronomers

11:48

consider it to be a near twin of

11:50

the Milky Way. We don't know exactly what

11:52

the Milky Way looks like, but it's pretty

11:54

close to this galaxy or that galaxy. And

11:57

really until we're able to send a spacecraft,

12:00

hundreds of thousands of light years away to be

12:02

able to get up above the disc of the

12:04

Milky Way, will we ever be able to actually

12:06

get an image and take a photo of the

12:08

Milky Way from outside of it. So until then,

12:10

we have to just theorize

12:13

what it probably looks like. Use our

12:15

imagination. And science. Taron

12:18

Pulacanti, do you think that astrophotography

12:20

as a hobby could be turned

12:22

into something serious? That's

12:24

a tough question. So you might

12:26

not know, but I am the

12:29

my father is a professional photographer.

12:31

So on the small island that

12:33

I grew up on, my

12:35

father was kind of like the historian

12:38

of the island, but also took portrait

12:40

photographs, also sold

12:42

all his photographs to the local

12:44

newspaper, also did art shows where

12:46

he sold photographs to rich

12:50

art collectors in Vancouver. And

12:53

also had his photographs published in various

12:55

books. And so

12:58

I know, like from personal

13:00

experience, what it was like to grow up

13:02

in a household where my father's income was

13:05

coming from being a professional photographer. Now

13:07

there were lines that he wouldn't cross

13:09

like, he just got sick of

13:11

doing wedding photography, he got sick of doing

13:13

portrait photos for people when they want it

13:16

done, like he would take photographs and he

13:18

would do like street photography and things like

13:20

that. But but he sort of had his

13:22

has limits and you know, limited his financial

13:25

return. We were poor, for

13:28

sure. And he also had to make money, driving

13:31

a backhoe and doing other, you know,

13:33

carpentry type jobs. So

13:36

I think, you know, it's always been incredibly

13:38

difficult to make a living being a photographer,

13:40

you're an artist. And I

13:42

think the same thing goes for doing astrophotography,

13:44

like if what you want to do is

13:46

only be an astrophotographer, and

13:49

have that be your living, I

13:51

don't think that's possible. Like there

13:53

might be a couple of people

13:55

who have patreons who are

13:57

selling their photos or the or the rights of

13:59

their photos for the covers of

14:01

various magazines, or they do

14:03

our shows and they're successful, you know, there's

14:05

going to be a handful across planet Earth,

14:08

but it is not a super viable form

14:11

of revenue. And I think that's fine.

14:13

Like I think that there are certain things that can

14:16

just remain hobbies and as soon as

14:18

you're trying to make money from them,

14:20

then it can pollute your enjoyment of

14:22

the hobby itself. You know, I think

14:25

astrophotography is one of the most rewarding hobbies

14:27

that I can think of as it relates

14:29

to astronomy. I mean, it's so great. You

14:31

are setting up this telescope, you are observing

14:33

photons that are coming from space, you are

14:35

putting in different kinds of filters, you are

14:37

choosing how long you want to do your

14:39

exposures, you're thinking about objects in

14:42

the foreground and the background. And

14:44

you are then working in Photoshop to

14:46

try to bring out various parts of

14:48

the of the image while at

14:50

the same time trying to maintain the raw

14:52

data that came your way. It's a fascinating

14:55

bottomless hobby with a ton of variables.

14:57

And those are the best kind, right? The ones

14:59

that are relatively straightforward to get

15:01

into, but are infinitely complex as you

15:03

really start to plumb the depths of

15:05

them. So I think if you want

15:08

to get into a hobby

15:10

of astrophotography, I think that's wonderful. And

15:12

I highly recommend it, you know, just

15:14

try to limit the rabbit hole, try

15:16

to limit how much you spend on

15:18

the hobby. The

15:21

top piece of advice that I have

15:23

for anybody who is really interested in

15:25

getting into astrophotography is that

15:27

you can save yourself a ton

15:29

of pain and money by

15:32

learning to do the image processing

15:34

first. So instead of going out

15:36

and buying a $10,000 telescope or $5,000 telescope, and then

15:41

taking raw data

15:43

and then trying to make those images look

15:46

really good. What you should do

15:48

is learn how to work with the images

15:51

themselves. And there is there's unlimited

15:53

numbers of images from the

15:55

Hubble Space Telescope, you can go to the

15:57

Hubble Space Telescope data archive, you can download

15:59

a images on any object that you can

16:01

imagine that nobody

16:04

has ever tried to

16:06

present artistically, because

16:08

it's just it was used scientifically. And

16:10

you can just learn

16:13

how to bring the from the raw

16:15

data format, the fits format that that

16:17

astrophotos are taken in, bring them into

16:20

Photoshop, separate out the layers, change

16:22

the contrast, sort of work with the

16:24

image to try and really bring out

16:26

the best version of it. This is

16:28

what Judy Schmidt does. And she

16:31

is often seen as a collaborator

16:34

on dozens of

16:37

very famous astrophotos, lots of press

16:39

releases from NASA, they'll give credit

16:41

to Judy Schmidt, she's fantastic. And

16:44

once you've built up those skills on

16:46

working with the raw image data, then,

16:49

and you're still into it, then

16:51

get a telescope, then start taking your own data

16:53

where you're getting images of the things that you

16:55

want to do. Because I promise you, like, if

16:57

you get into this, you will reach

16:59

this brick wall where you're taking these images,

17:02

and you don't like them, because

17:04

your limiting skill is the data processing. And

17:06

so you'll try to you'll take these images,

17:08

the raw data is in there, Judy can

17:11

make your images look amazing. But you don't

17:13

have the skills yet in the processing side.

17:15

But if you practice the processing side, get

17:17

really good. It's all free. I mean, okay,

17:19

you need access to Photoshop, you know, if

17:21

you use gimp or whatever. And then when

17:23

you feel like you're really good at processing

17:26

images from the greatest telescopes that have ever

17:28

been built, you know, James Webb, Hubble Space

17:30

Telescope, the very large telescope, you can work

17:32

with that data, then come

17:34

back around and get your own telescope and

17:37

then start taking your own pictures. So you

17:39

can really get into this hobby and get

17:41

really good at it without spending any money,

17:43

which is amazing. If

17:45

you want to support the work that we do at

17:47

universe today, why don't you consider joining our Patreon club.

17:49

Now, I sort of talk

17:51

about the paid patron members, but I want

17:53

to remind you that you don't have to

17:55

be a paid Patreon member, you can be

17:57

a free member as well, you can subscribe.

18:00

subscribe to us on Patreon totally for free, then

18:02

you'll get notified whenever any of the new videos

18:04

and stuff that we release goes live. Often we

18:06

just release it at the same time. And the

18:08

cool thing about that is there's no ads. So

18:10

if you watch our stuff on Patreon, there are

18:12

no ads and you know that you're not going

18:14

to lose our videos in the shuffle of

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the YouTube subscriptions. You're not beholden to

18:19

some algorithm. You'll get a notification whenever

18:21

we release a new video and it's

18:23

completely free. Now, obviously my

18:25

hope is that you will watch all this

18:27

amazing content that we're releasing and think about

18:29

the additional content that you could access to

18:32

and you will be intrigued and

18:34

tempted to join the full Patreon. But

18:36

at the same time, I would rather

18:38

have you be free than just not

18:41

following our content at all. Now, I

18:43

want to celebrate some of our recent

18:45

subscribers. Thanks to Chris Vincent, Simon Oliphant,

18:48

Dan Miller, Bill Vass, Mason Hall, Mutt,

18:50

Colin Jones, Jeff Henderson, Iron Owl, Judy

18:53

1x4x9, and Roch Gadsen.

18:55

Join the club at patreon.com/universe

18:58

today. Old Uncle

19:00

Bob, if gravity is such a weak force, then

19:02

how does it factor at such enormous distances? Of

19:05

all of the forces that we know of,

19:07

yeah, gravity is the weakest force at the

19:09

smallest scales. So if you

19:11

have say the gravitational force of

19:13

an entire planet, and you've got

19:15

a magnet that is attached to

19:17

your refrigerator, the magnet is able

19:20

to hold stronger than the entire

19:22

gravitational force of planet Earth. But

19:25

over the longest distances, gravity takes

19:27

over. So things like the electromagnetic

19:30

force, strong force, the weak force,

19:32

they drop more quickly

19:34

than gravity does. And

19:37

so when you have the

19:39

mass of an entire galaxy, an entire galaxy

19:41

cluster, it can reach out across 10s

19:43

of millions of light years, I guess,

19:46

you know, you are being affected by

19:48

the gravity of the entire observable universe

19:50

right now. And I guess you are

19:52

theoretically being affected by the

19:54

electromagnetic force of the entire universe

19:57

as well. It's just that the

19:59

strength strength of that field is

20:01

very weak compared to the strength

20:03

of the gravitational field. So up

20:06

close, electromagnetism is stronger, but at

20:08

greater distances than gravity starts to

20:10

take over. Lily Rose, what is

20:12

the coldest place in the universe? So

20:14

like unless we discover some kind

20:16

of alien scientific lab, the coldest

20:18

place in the universe is here

20:20

on Earth. I mean, there are

20:22

labs that are bringing material down

20:25

to just an insignificant

20:27

fraction above absolute zero. And there's no

20:29

way for you to get that

20:31

level of coldness out in space

20:34

just naturally. Instead, you know, the

20:36

background temperature of the universe is

20:38

around what, three degrees

20:41

Kelvin, four degrees Kelvin. So

20:43

very cold, but not absolute zero

20:46

cold. But there

20:48

are places in the universe that are

20:50

unnaturally cold, that are colder than

20:52

you would expect. So

20:55

an example of this is the boomerang

20:57

nebula, which is estimated to have a

20:59

temperature of one Kelvin. So

21:01

it is cooler than the background

21:03

temperature of the universe. And

21:05

actually don't know why the boomerang nebula

21:07

is the coldest place in the universe.

21:10

And I don't think scientists know why

21:12

either. Like obviously, some mechanism is extracting

21:14

heat from the system through

21:16

outflows of gas or something like that. Finneas

21:19

994, what is your favorite thing to cover at

21:21

the moment? So I describe this

21:24

thing of like, what

21:26

is my favorite thing to cover at the moment,

21:28

these are my obsessions. And I

21:31

generally have a

21:34

few things that I am obsessed

21:36

with at any point.

21:39

And then I reach

21:42

out to people, I do a bunch of

21:44

interviews, and I sort of satisfy that curiosity

21:46

and that obsession. And then I

21:48

move on to another thing. And so when I'm

21:50

looking through all of the big stories that are

21:52

coming out, all of the press releases, all of

21:54

the conferences, all of the trade papers, all of

21:56

the research journals and so on, and I see

21:59

one So

26:01

this is an extremely profound question. And this

26:03

is something that philosophers had been thinking about

26:05

for a long time. And the name for this

26:07

is called Olber's Paradox. And so when you think

26:09

about it, like if we live in

26:12

a universe that

26:14

is infinite in all directions,

26:17

and timeless, that lasts

26:19

for an infinite amount of time, it's always been here,

26:22

then in whatever direction that

26:24

you look, there should be a star

26:27

somewhere in that field, you know,

26:29

at that exact point, now might be close,

26:31

it might be far, it doesn't matter. Because

26:33

eventually, if it's infinity, there's going to be

26:35

a star there. And so the night sky

26:37

should look white, it should look like the

26:39

color of all of the stars

26:42

of the universe. But when

26:44

you look out into the sky, we

26:46

don't see all of the stars in

26:48

the universe, we see darkness, and then

26:50

we see occasional pinpoints of light, which

26:52

are the stars. And so why

26:54

is this? And the answer is like

26:56

when we went back to that first two

26:59

things that I said, that the universe is

27:01

infinite, yeah, it probably is infinite, it might

27:03

not be infinite, but it's essentially infinite. But

27:06

it also has to be timeless. And it's not

27:08

timeless, that the universe has a

27:10

finite age, it is 13.8 billion years old.

27:12

And so when you look

27:17

out into the universe in any one direction, you're

27:19

only seeing to a maximum of 13.8 billion years

27:22

in time, and

27:24

that there is still more blank

27:26

space in the regions in

27:29

between those stars, then there

27:31

are light. And so this is why we

27:33

don't see a sky

27:35

that is bright, the

27:37

color of a star, we actually see

27:40

darkness. And then the other aspect

27:42

of this is that this color

27:44

of the light that is reaching

27:46

our eyes has been redshifted to

27:49

a region of the spectrum that we

27:51

can't see. So if you could see

27:53

in the microwave, then you would see

27:55

light in all directions, you would see

27:57

the color of the sky, which is

27:59

essentially a time