Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / Galactic Ejections & Black Hole Explosions: Exploring Cosmic Queries

Transcript

Galactic Ejections & Black Hole Explosions: Exploring Cosmic Queries · Space Nuts: Astronomy Insights & Cosmic Discoveries

0:00
Andrew Dunkley: Hello again. This is Space Nuts, a Q and A
0:03
edition where we talk. Well, whatever you
0:05
want to talk about. Basically, it's your
0:08
show. This part of it, uh, every, uh, Monday
0:10
we release these online. But, um.
0:13
Yeah, uh, so what questions are we going to
0:15
be dealing with today? Well, uh, we've got a
0:18
question from Clark asking about the ejection
0:20
of planets and stars. It's like being kicked
0:23
out of a nightclub, really. Scott, uh, is
0:26
asking about the death of black holes.
0:28
Rusty wants to know about the, uh. Uh, this
0:31
is an old chestnut, this one. We've done it a
0:32
few times, but I really like this question,
0:34
so we'll, we'll do it. It's a what if about
0:37
the sun and a story or a
0:40
question about resources for getting into
0:42
astronomy. If you want to be, uh, uh, you
0:44
know, a beginner, we'll tell you all about it
0:46
on this episode of space nuts. 15
0:49
seconds.
0:50
Professor Fred Watson: Guidance is internal. 10,
0:52
9, ignition sequence. Star
0:55
space nuts. 5, 4, 3, 2. 1, 2,
0:58
3, 4, 5, 5, 4, 3, 2, 1.
1:01
Andrew Dunkley: Space nuts. Astronau Feels
1:04
good. And unravelling the
1:07
unravel, ravelable is
1:09
Professor Fred Watson Watson. I thought I'd
1:11
try that. Didn't work. Astronomer at large.
1:14
Professor Fred Watson: Hello, Fred Watson. Uh, unravelling
1:16
the ravioli, is that, uh.
1:18
Andrew Dunkley: Yeah, that might be easier. Yeah, might be
1:21
easier to say too.
1:22
Professor Fred Watson: Yes.
1:23
Andrew Dunkley: Uh, how are you, Fred Watson?
1:24
Professor Fred Watson: Very well, thank you. Andrew. Good to see you
1:26
again as always. And, um, looking forward to
1:28
hearing what our listeners have dished up for
1:30
us today.
1:31
Andrew Dunkley: Yes, why don't we get straight into it? Um,
1:34
our first question comes from ORK Auckland,
1:36
New Zealand. Beautiful city. If you've never
1:38
been there and you're thinking of a holiday,
1:40
that's not a bad choice. Love Auckland.
1:43
Um, and get out on a boat and go and visit
1:46
one of the islands where all the vineyards
1:48
are. It's awesome. Anyway, Clark, uh,
1:51
asks, um. Hi, guys. Love the podcast.
1:54
And I have a question.
1:54
Professor Fred Watson: Good.
1:55
Andrew Dunkley: Cause this is the Q and A edition.
1:56
Clark, your timing's perfect. Uh, can a sun
1:59
or planet be ejected from a galaxy or
2:02
is the gravity from the galaxy centre too
2:04
strong for this? Uh, I've always wondered if
2:07
a lonely star or planet could be sitting
2:10
between us and, say, the Andromeda galaxy.
2:13
Thanks. That comes from Clark. Uh,
2:15
we've kind of talked about this before. We
2:17
know there are rogue planets, we know there
2:19
are stars that get bumped around. But, um,
2:22
this is kind of within the
2:25
galaxy. Could they be ejected
2:28
beyond? I mean, let's do the whole spectrum
2:30
of ejection. You know, you're not good
2:32
enough. Get out.
2:35
Professor Fred Watson: Um, and in fact, uh, there's more of these
2:37
things than you might think. And the ones
2:40
that we can detect are all stars. I'm not
2:42
sure that there's been any detections of
2:45
interstellar, sorry,
2:47
intergalactic rogue planets or
2:49
orphan planets. I think they're all stars.
2:52
But yes, the space in between the galaxies,
2:54
the intergalactic medium
2:57
as it's called, uh, you kind of imagine
3:00
it would be empty, at least empty of stars.
3:03
There's quite a lot of stuff in there
3:05
actually. Um, one of my
3:07
colleagues, Ken Freeman for a while was
3:09
really interested in, uh, what are called
3:12
extra galactic planetary nebulae. These are
3:14
stars that have basically died, uh, shed
3:17
their, uh, outer layers and formed what we
3:20
call a planetary nebula. Nebula, nothing to
3:22
do with planets. It's a name given to it by
3:24
William Herschel because they look like
3:26
planets, they're round. Um, so
3:29
those are obviously things where a star has
3:31
been ejected from a galaxy.
3:34
Uh, and indeed there are some between
3:35
ourselves and the Andromeda
3:38
galaxy, um, as Clark
3:41
mentions. Uh, but, um,
3:44
more to the point, we can
3:47
measure the velocities of stars
3:50
in our local neighbourhood and when you do
3:52
that, there are some that are going
3:55
fast enough that they will be
3:58
ejected from the galaxy as a whole.
4:01
Uh, in other words, um,
4:04
planets, sorry, stars that are
4:06
disappearing. And the usual ejection
4:09
method is probably, uh, a
4:12
star that gets too close to the supermassive
4:14
black hole in the middle of the galaxy gets
4:17
this gigantic gravitational kick,
4:21
uh, that hurls it out of the galaxy.
4:24
Uh, uh, often if stars interact with one
4:26
another, particularly when you've got binary
4:29
stars, stars that come in pairs, um,
4:31
something might perturb that, the fact that
4:33
they're orbiting each other around the common
4:35
centre of mass, um, and one might get
4:38
booted out, the other might wind up
4:41
going somewhere else. Uh,
4:45
but that would not necessarily give you
4:47
enough energy to leave the galaxy,
4:50
uh, as a whole. And in that regard
4:53
Clark's point is well made. Is the gravity
4:55
from the galaxy centre, uh, too strong for
4:58
this for a star to be ejected from the
5:00
galaxy? Um,
5:03
and it's not, but it
5:06
needs a kick by something as massive as a
5:09
black hole to give you the impetus, the
5:11
energy to leave the galaxy. Uh,
5:14
so we essentially have
5:17
used that, certainly with, um,
5:21
what we call the RAVE survey. The Radial
5:24
Velocity Experiment was carried out on, um,
5:27
the UK Schmidt telescope in the early 2000s,
5:30
finished it in 2013. The survey that
5:33
I was the project manager for,
5:36
uh, we measured the velocities of half a
5:38
million Stars altogether. And one of the
5:41
first papers that came out of
5:44
um, um, that survey when we
5:47
didn't have all that many stars that we'd
5:49
measured their velocities for. But
5:52
uh, it was a paper that was basically about
5:55
looking at stars that have been
5:58
ejected from our Milky Way galaxy,
6:02
uh, or are going to be ejected from the Milky
6:04
Way galaxy. They've got enough speed to do
6:06
that um, and work out
6:09
what the escape velocity of the galaxy is.
6:12
It sounds like picking yourself up by your
6:14
own bootlaces but you can do it. Once you
6:17
know the escape velocity of the galaxy you
6:19
know its mass. So this was a way of weighing
6:21
the galaxy which we did very early on in the
6:24
rave survey. I think the numbers have changed
6:27
slightly now because we've got far far more
6:30
particularly from the Gaia ah survey uh,
6:32
which was um, a
6:35
spacecraft that was measuring um, very
6:38
accurately the speeds of stars across the
6:40
line of sight, not necessarily along
6:43
the line of sight. Anyway, the bottom line is
6:46
to cut a short question, uh,
6:49
a long answer to a short question shorter,
6:52
the answer is yes Clark, you can uh, and we
6:54
see them and we can measure them and we can
6:56
actually get useful information from them.
6:58
Andrew Dunkley: M. Uh, the escape velocity of our galaxy
7:02
uh, at the centre is roughly 220 to
7:05
230 kilometres per second.
7:08
Uh, an object would need an additional boost
7:11
of about 317 to 330
7:14
kilometres a second in the direction of
7:15
motion to completely break free of the
7:18
galaxy's gravitational pull.
7:20
That's pretty heavy stuff, isn't it?
7:23
Professor Fred Watson: Yeah, and that tallies with my recollection
7:25
uh, about um, in
7:28
what we call the solar rays radius, the sun's
7:30
position in the galaxy because the escape
7:33
velocity varies depending on where you are in
7:35
the galaxy.
7:37
Andrew Dunkley: By comparison, Earth's escape velocity is
7:39
only 11.2.
7:41
Professor Fred Watson: Correct. That's right. Um, but the
7:44
galaxy's escape velocity in the region of the
7:46
sun is about 400 kilometres per second.
7:49
Uh so yeah, it's because it's a bigger
7:52
object.
7:53
Andrew Dunkley: Yeah, that's tough going.
7:57
Professor Fred Watson: Yep. But stars do it. We've got
7:59
something.
8:00
Andrew Dunkley: Oh they do. It prompts a question in my mind
8:02
that slipped out of my head but now it's
8:04
jumped back in again. Uh, are there
8:06
likely to be ejections as a
8:09
consequence of the merger between the Milky
8:12
Way and Andromeda galaxies?
8:14
Something's going to get kicked out.
8:16
Professor Fred Watson: Yeah, I think whenever you have a
8:17
Andrew Dunkley: company merger someone gets the boot.
8:22
Professor Fred Watson: Um, yeah, it will be um, look, it'll
8:24
be kicked out uh city. I think
8:28
when that happens there will be
8:31
such high, um, levels
8:34
of gravitational interactions between
8:37
stars and stars, stars and giant molecular
8:39
clouds and stars and black holes that
8:42
we'll probably see, um, the resulting
8:46
galaxy, which, as you know, will be called
8:48
Milcomeda, uh, the Milky Way and the
8:50
Andromeda galaxy combined. Milkomeda, uh,
8:53
will probably eject a very large number of
8:55
stars, many more than we see being ejected
8:57
from the Milky Way.
8:58
Andrew Dunkley: Yeah. Ah, well, before I got into radio, I
9:00
was a banker, believe it or not, and I
9:03
actually worked.
9:04
Professor Fred Watson: Yeah.
9:05
Andrew Dunkley: Yeah. And I,
9:08
I, I worked for a bank that merged with
9:10
another bank. And it was kind of like
9:12
Milkometer, because we had twice as many
9:14
tellers, twice as many managers, twice as
9:17
many examiners, twice as many,
9:20
uh, general hands, um, all those, those
9:22
banking positions that, uh, yeah, we had
9:24
twice as many people, um, because, you know,
9:27
they closed half the branches because you
9:28
didn't need two branches of the same bank in
9:30
the same street of every town and city in
9:31
Australia. So, yeah, we eventually it
9:34
created this conglomeration of people and
9:36
there weren't enough jobs for them, and it
9:39
got, yeah, it's part of the reason I got out
9:41
and got into radio, because there wasn't much
9:43
of a future for me there. So
9:46
it's just how the universe works sometimes.
9:50
Indeed. All right, thank you, Clark.
9:53
Um, that was a great question. Lots of fun to
9:55
tear that one apart. Boom. Boom. Question,
9:57
uh, two today comes, uh, from,
10:00
um, Scott in Hobart,
10:02
Tasmania. Hello. Fred Watson and Andrew have
10:05
a question for you. I understand that Hawking
10:07
radiation will cause black holes to
10:09
eventually evaporate. I think I heard 10
10:12
to the 76 years. Uh, what I
10:15
haven't heard described is what happens to
10:17
the black hole once the mass falls below the
10:20
threshold where light can escape. Will the
10:23
loss of equilibrium between mass and light
10:25
pressure result in an explosion? Perhaps you
10:27
can talk us through the final process in the
10:30
life cycle of a black hole. Thank you both
10:32
for a terrific podcast. Thank you, Scott, for
10:35
the good wishes and the great question. Yeah,
10:38
um, I've never thought about a black hole
10:40
getting to the point where its gravity can't
10:42
hold back the light anymore.
10:45
What happens then?
10:48
Professor Fred Watson: Um, so actually,
10:51
uh, um, um,
10:55
Scott. I beg your pardon? I'm trying to get
10:57
my nose here. Yeah, Scott is
11:00
right. Uh, there's an explosion
11:03
and it's very violent. Uh, and
11:07
sometimes it's got a name. It's called the
11:10
Final burst, which is, uh,
11:13
a bit modest really, for what kind of
11:15
energies that they're talking about.
11:17
Um, and so it comes about,
11:20
and we've talked about this before, Andrew,
11:23
A uh, black hole's temperature is
11:26
inversely proportional to its mass.
11:29
So the more massive a black hole is, the
11:31
cooler it is. And the ones we've talked about
11:33
in the past have been very cold indeed, uh,
11:35
just a few degrees above absolute zero.
11:39
But as the mass gets less, uh,
11:41
it gets hotter. And um, and
11:44
so that produces
11:48
a radiation from the black hole.
11:51
And we're talking now about a time, yes,
11:54
when it can no longer hang on to everything.
11:57
And you get this sort of runaway, uh,
12:00
effect, like a runaway greenhouse effect,
12:02
except it's not the same. But basically
12:05
that runaway causes um,
12:08
the explosion. Um,
12:13
I mean the theory, you know, this is all
12:15
theoretical of course, but the theory
12:18
predicts that the temperature of a dying
12:21
black hole right at the end of its life
12:23
will increase to billions of degrees.
12:27
And in the final second
12:30
the evaporation rate becomes so extreme
12:33
that you get this enormous amount of energy
12:35
that comes from uh, the
12:38
dying black hole. Uh, and
12:41
there are possible different
12:44
end states. Um, and I guess
12:47
the one, the most logical one
12:50
is that it totally evaporates, so it
12:53
becomes nothing. Uh, all the mass has
12:56
gone in a flash of
12:59
really high energy particles, probably
13:01
gravitons as well as photons and other stuff.
13:04
It basically uh, just
13:07
flashes out everything, uh, and
13:10
once again leaves nothingness behind.
13:13
There is one, uh, I mean we're talking now
13:16
about theoretical stuff. Some others
13:19
have suggested that it shrinks to
13:23
something called uh, the Planck
13:26
mass, uh, where
13:28
quantum gravity effects
13:31
become the dominant feature. Um,
13:34
and essentially you get, and that
13:38
sort of stops the evaporation, if I can put
13:40
it that way. Um, so there's
13:43
something gets left behind, a sort of
13:46
quantum element. And then
13:49
finally, um,
13:54
Again, when you look at the details, uh,
13:57
it's probably uh, another
14:00
possibility rather than all these things
14:02
happen as well. I think, uh, we're talking
14:04
about separate cases here that may have
14:07
different, different starting points.
14:09
I'm not sure, I'm not actually sure how uh,
14:11
robust this theoretical stuff is as well.
14:14
But some authors have suggested that
14:17
you get gravitational shock waves as
14:20
well. Basically when it gets
14:23
to the end, uh, you get a shockwave as well
14:25
as that explosion. Uh, and
14:28
so what you might call trapped
14:31
information, the stuff that Hawking argued
14:34
about with another well known cosmologist, I
14:36
can't remember who it was, uh, that trapped
14:39
actually gets blown out into the universe
14:41
because of a gravitational shockwave. All
14:44
these things sound like, you know, using posh
14:47
names for something dramatic that happened.
14:49
And I'm not sure how many of them are really
14:53
very robust theories, but it seems to be the
14:55
case that the likelihood is there will be a
14:58
violent explosion at the end of the Hawking
15:00
radiation period as
15:03
um, uh, Scott says, you know, 10 to the
15:06
76 years. It's a huge number of years down
15:08
the track.
15:09
Andrew Dunkley: Yes. A black hole doesn't go out quietly.
15:12
Professor Fred Watson: That's the bottom line.
15:13
I think that's the succinct way of expressing
15:16
what I've just taken half an hour to say.
15:17
Andrew Dunkley: Yeah, that's fine, yeah.
15:21
It's our job to take half an hour to say
15:23
something that takes and
15:24
Professor Fred Watson: it's your job to make it succinct. So that's
15:26
good. And you do it very well. Andrew, I have
15:29
to say.
15:30
Andrew Dunkley: Oh, thank you Fred Watson. Uh, and thank uh,
15:33
you Scott for your question. Lovely to hear
15:34
from you. This is Space Nuts, a Q and A
15:36
edition with Professor Fred Watson Watson and
15:39
Andrew Dun.
15:44
Space Nuts. Uh, now Fred Watson, we have an
15:47
audio question. This is an old chestnut, but
15:49
I, I do like uh, these what if questions.
15:52
This is Rusty.
15:53
Professor Fred Watson: Hey guys, this is Rusty Mac from
15:56
Brooklyn, New York. Uh, they say that the
15:59
speed of light is the fastest thing known to
16:01
man. And if the sun instantly
16:04
disappeared, we would still have light for 8
16:06
minutes and 20 seconds because that's how
16:09
long it takes for light to get from the sun
16:11
to the Earth. So if the sun
16:14
disappeared suddenly, would the Earth
16:17
still be gravitationally locked to the solar
16:19
centre? Or would Earth, uh, and all the
16:22
other planets get flung off into interstellar
16:25
space immediately or would there be a
16:27
delay? And if that happened instantly,
16:31
what would that mean? That gravity was
16:35
faster than the speed of light and that
16:38
gravity waves are actually the fastest thing
16:40
in the universe. Mhm.
16:43
Andrew Dunkley: Okay, thank you Rusty and uh, hope all is
16:46
well in Brooklyn. I walked across the
16:47
Brooklyn Bridge last year from Brooklyn into
16:50
Manhattan and uh, it's a heck of a walk,
16:52
which is worth doing if you're a tourist.
16:55
Um, lovely, lovely place. Love the
16:58
buildings around that part of the world.
17:01
Yeah, gee, it's, it's a. Yeah, it's
17:03
just so different to anything we have here
17:05
really. Well, parts of Sydney probably
17:08
resemble it, but nothing out where I live.
17:10
Um, the vanishing of the sun
17:13
instantaneously. We have had that what if
17:15
question once or twice before over the last
17:18
ten years or so. Uh, but it's worth
17:19
revisiting. I wouldn't like to think what
17:22
could cause such a horrible thing to happen
17:25
because I don't imagine that we would be
17:28
around long to witness the long term
17:29
ramifications.
17:32
Professor Fred Watson: No, that's right. Uh, it would be
17:35
cataclysmic. Um, but it's a good thought
17:37
experiment to say, okay, what happens if the
17:39
sun vanishes? And Andrew, you know the answer
17:42
to this because we've talked about it before.
17:44
So.
17:45
Andrew Dunkley: Well, we'd have 8
17:47
minutes and 20 seconds of sunlight and then
17:50
we would be uh, plunged into
17:53
eternal darkness and all the dogs and cats
17:56
would start living together and um,
17:59
everything would, would, would die. There'd
18:00
be no photosynthesis, we'd uh, we'd not be
18:03
able to produce food. We'd um, we'd, we'd, I,
18:06
I, because we are not being held into a
18:08
gravitational orbit around the,
18:11
the sun, uh, everything would start to drift
18:14
off into the Never, never uh, never
18:17
to be heard from again. And, and we wouldn't
18:19
last very long at all.
18:21
Professor Fred Watson: Um, that's certainly true.
18:22
Andrew Dunkley: And it would become cold. It would become
18:26
very cold.
18:27
Professor Fred Watson: Absolutely. Um, a bit of
18:30
radiation from the Earth itself because of
18:33
the nuclear processes that are going on
18:35
inside it. But they're pretty low level.
18:38
We're not a star, we're a planet. Uh, and so
18:41
yeah, you wouldn't be that warm. Um, but
18:45
in answer to the question though,
18:48
uh, actually you
18:51
would still be attached to the sun
18:54
for the 8 minutes and 20 seconds that it took
18:56
gravitational waves, waves to reach our uh,
18:59
planet. So uh, gravitational waves have been
19:02
demonstrated a number of times and
19:03
theoretically this was predicted by Einstein.
19:06
They travel at the speed of light.
19:08
Gravitational waves travel at exactly the
19:11
same speed. So that means that yes,
19:13
gravitational waves are the fastest thing in
19:14
the universe along with light and radio waves
19:17
and all the rest of it. So um, there will
19:20
be an 8 minute 20 second delay before we
19:24
not only went dark, but also wandered off
19:26
into the wide blue yonder. Uh, without the
19:28
sun to hold us in orbit, we'd be zooming off
19:30
at 30 kilometres per second in some straight
19:33
line depending on it would be heading,
19:35
depending on where the when, at what point
19:38
in its orbit. The sun in the Earth's orbit,
19:40
the sun disappeared. But it beliked a
19:43
horrible thought. Slingshot effect. Yeah, it
19:44
is a horrible thought. You should write a
19:46
science fiction story about this.
19:47
Andrew Dunkley: I think probably could. You know what I'm
19:50
doing at the moment? I'm writing a prequel to
19:52
um.
19:52
Professor Fred Watson: Yeah, you said.
19:53
Andrew Dunkley: Yeah, the Human Epoch. Yeah.
19:56
I'm halfway through the first book. I'm
19:58
trying to uh. Cause the hero of the
20:01
Human Epoch trilogy is um, a fellow
20:04
by the name of Gary Forrester. And I made him
20:07
Canadian because the Canadians never get
20:08
mentioned anywhere a lot of the time. And
20:11
I thought they're such nice people, they
20:13
certainly deserve a mention. So I made my
20:15
hero Canadian. Could have made him
20:17
Australian. Could have gone down the American
20:19
road. But I think we've had enough American
20:20
heroes in science fiction for the time being.
20:23
So I went Canada, and, um, I've decided to
20:26
write his story leading up to the beginning
20:28
of the human epoch, um, because I like the
20:31
character so much, um, but I don't
20:34
think he could even save us from, uh, from
20:36
something as cataclysmic as the sun
20:38
vanishing. I wonder what
20:41
could cause that. And I don't think there's
20:43
anything that could wipe it out instantly.
20:45
But maybe a black hole venturing into our
20:47
vicinity would not be a good thing.
20:50
Professor Fred Watson: That's right. But if the black hole was black
20:53
hole worth its salt would be, uh, seized into
20:56
orbit around that, uh, long before it gobbled
20:59
up the sun. So we'd know about it.
21:02
Andrew Dunkley: Yes. We'd also get a lot heavier.
21:05
Maybe.
21:06
Professor Fred Watson: Indeed. Probably so. Yeah.
21:09
Andrew Dunkley: Yeah. All right. I, uh, think we covered
21:11
that.
21:11
Uh, Rusty, thanks for the question. Great to
21:13
hear from you. Love the accent.
21:17
Okay, we've had a problem here.
21:19
Professor Fred Watson: This is Houston.
21:19
Andrew Dunkley: Say again, please. Houston, we've had a
21:22
problem. We've had a main beam. Roger,
21:24
maineville. Okay, standby 13. We're looking
21:26
at it. Stay smarts. Our
21:29
final question today is, um,
21:32
more of a. An educational query.
21:35
I've, uh, recently gotten into astronomy.
21:38
What are some of the resources for a
21:40
beginner? Thanks. I, uh, haven't got a name.
21:43
Just B, from Sydney. Thanks. Bea
21:46
wants to get into astronomy, or has just
21:48
started. Um, what would you recommend,
21:50
Fred Watson, as somebody who's had a
21:53
wonderful career in that exact
21:55
science?
21:56
Professor Fred Watson: Well, I'd start with, um, there's this
21:59
really good podcast called spacenots that
22:02
anybody wanting to get into astronomy could
22:05
perhaps listen to as a resource.
22:07
Um, ah, a lot depends on what you
22:10
mean. Whether you want to be observing
22:13
the sky, uh, or whether you're more
22:16
interested in the stories that we often
22:18
cover on space nuts about the way the galaxy
22:21
behaves and whether stars can be ejected from
22:23
galaxies and all of that sort of stuff. Um,
22:26
and there's certainly plenty of
22:29
material on the World Wide Web,
22:32
uh, from reliable sources, um,
22:35
including NASA, including Universe Today,
22:38
an old friend of, uh, this podcast, including
22:41
Ars Technico, another good friend, and
22:43
phys.org, uh, they're all places where
22:46
you can get good information that's P, P, H,
22:49
Y, S, not F, I, double Z.
22:52
Um, so, uh, those are the sorts of things.
22:55
Now, um, I also would point you
22:58
if you're interested in learning your way
22:59
around the sky to some of the
23:02
sky apps that there are. There's
23:05
several of them.
23:06
Um, I have one on my phone that
23:09
I'm a cheapskate, so I never went for
23:12
the higher version, figuring that because I'm
23:15
an astronomer I should know my way around the
23:16
sky anyway. But sometimes when you can only
23:18
see one object because of the cloud clouds,
23:20
it's a good way of finding out what it is.
23:23
Um, lots of stuff like that. Um, hardware,
23:26
of course, telescopes, binoculars. I'm
23:29
always, uh, a, uh, fan of,
23:32
in terms of astronomy, because even if you've
23:34
got a site where you've got some light
23:36
pollution and you're in Sydney B,
23:39
so that, uh, it means you probably
23:42
do have. It is. But you can still
23:45
see, you get lovely views of the moon,
23:48
uh, bright objects like the Orion Nebula.
23:50
Even in light polluted, you can see them.
23:53
Uh, and the planets. Binoculars are not good
23:56
enough to show up the rings of Saturn. Um,
23:59
but a powerful pair of binoculars will
24:02
show you some of the satellites of Jupiter
24:04
and see the way they're moving, they look
24:05
like little stars right next to Jupiter. Uh,
24:08
and then if you want to get into telescopes,
24:11
there are one or two companies which
24:12
specialise in optics for astronomy.
24:15
Um, and they are for the most part,
24:18
and certainly the one I'm thinking of, which
24:20
is in Glebe, Sydney, uh,
24:23
I won't give because that would be
24:25
advertising, but, uh, they all know who I
24:27
mean. Uh, it's, uh, not far from the fish
24:29
market. There you go.
24:30
Uh, that's a great place, uh, to get good
24:33
advice on what you might need for what
24:36
interests you and for what you can afford.
24:39
Uh, it's a place where, uh, the
24:42
staff are not just there, uh, because it's a
24:44
job. They're there because they're passionate
24:46
about astronomy themselves and they want to
24:48
enthuse, uh, other people in the same way
24:50
that they are. So you get really good advice.
24:52
And that's true, I think, with other people.
24:54
Um, uh, astronomy
24:57
optics centres around the country. There's
25:00
several I can think of some in Melbourne and
25:02
in Brisbane and elsewhere too.
25:06
Of course, then you're starting to spend big
25:08
money and it really depends
25:11
on what your resources are like and what your
25:13
interests are. I still
25:17
love, um, a planisphere,
25:20
which is a piece of hardware, goes back
25:23
at least 2,000 years. Uh, it's a little
25:26
analogue computer, usually two cards, one
25:28
with a hole in it, one with a star map on it
25:30
and you can dial up the date and time on the
25:32
edge and it gives you what the stars look
25:34
like, of course, you can do the same thing
25:36
online now. Um, and they're much more
25:39
accurate. And of course they show the planets
25:40
the online versions, which the old cardboard
25:43
or plastic ones don't. But I've always been
25:45
very fond of planispheres.
25:46
Andrew Dunkley: I'm just looking at some pictures of them
25:48
now. Yeah, I know what you're talking about.
25:53
Professor Fred Watson: Sometimes called a star wheel. Um, I've still
25:56
got the first one I ever bought when I was, I
25:58
think 15. Uh, it's a Phillips
26:01
planisphere. Uh, it's the 5 inch version.
26:04
It was the small one, but it still works.
26:07
Um, of course I see the sky from a different
26:09
hemisphere now, so I've also got ones from
26:12
the southern hemisphere too.
26:14
Andrew Dunkley: That's pretty cool. Another thing B that you
26:17
may want to consider, given our current level
26:20
of technology is, um, something like I've got
26:23
now, which is a smart telescope. Yeah.
26:26
And, um, you know, on a clear night you can
26:28
put this outside in your backyard and then
26:30
sit in the comfort of your lounge room,
26:32
especially if it's a cold night, and
26:36
photograph, uh, things you can't see with the
26:38
naked eye and would struggle to see with
26:40
binoculars. Um, and
26:43
keep the images that you've taken with it.
26:45
And um, it. A lot of them have built
26:48
in educational information. They can tell you
26:50
what you're looking at and explain who found
26:52
it, when they found it, what it is, why it
26:55
is. It's incredible technology. And
26:58
they've built them so well that they
27:01
actually have light pollution filters
27:04
built into them. So even, um,
27:07
the last few nights here, as we record,
27:11
have been very, very m. Uh,
27:14
bright nights with the moon. We had a full
27:16
moon a few nights ago. Um, doesn't bother the
27:18
smart telescopes. They just filter all that
27:21
out and, um, you can still
27:24
see a really good image.
27:26
Uh, and I've found a good trick. Um,
27:29
when you get your image, I actually adjust
27:31
the image as it is being, um, recorded by
27:34
the system because it does stacking. Um,
27:38
uh, I'll then put it through an
27:40
AI, um, piece of AI
27:43
software and say, I want you to just
27:46
tidy this up. I'm paraphrasing. I tell it
27:48
exactly what I want and
27:51
it will enhance the image even further.
27:54
I showed you Fred Watson. I took a photo of
27:56
the moon with it the other day and then I put
27:58
it into ChatGPT and said, can you enhance
28:00
this, sharpen it up, show me a bit more
28:02
detail in the cratering. And it just went
28:05
bang. And the image I got was, was
28:08
stunning.
28:09
Professor Fred Watson: I thought it is, it's remarkable. Yeah,
28:12
it is, absolutely.
28:12
Andrew Dunkley: So that's something to consider. And it's a
28:15
really inexpensive way of actually getting
28:17
into astronomy. Uh,
28:21
I didn't mention the brand of mine, but
28:25
they're all very, very popular. They're all
28:27
very good. There are a whole bunch of them.
28:28
Some of them are, um, in the hundreds of
28:30
dollars. Some are in the thousands of
28:32
dollars. It just depends what you want to
28:34
spend. But for someone like
28:36
me, who, who doesn't want to spend
28:39
hours and hours outside in the dark in the
28:41
cold because it gets damn cold out here in
28:43
winter, um, that's the perfect solution.
28:46
So, yeah, might, um, be worth considering.
28:49
That's just my piece of the pie.
28:52
Professor Fred Watson: Well, I'm glad you put that in as well
28:54
because that's a very important resource in
28:56
today's day and age.
28:59
Andrew Dunkley: Indeed. And, uh, thank you
29:02
for the question, uh, Bea.
29:04
And um, good luck with your future in
29:06
astronomy. And that brings us to
29:09
the end of the show. Fred Watson, thank you
29:11
so much.
29:12
Professor Fred Watson: A, uh, great pleasure, Andrew. I'm glad we
29:14
made it without a hiccup. And, uh,
29:17
great to have all those questions as well.
29:18
Thought provoking as always.
29:20
Andrew Dunkley: And please send us more questions, uh,
29:23
because it's going to sound weird. This is
29:25
time dilation at its absolute best. Um,
29:28
Fred Watson and I will talk again next week,
29:30
but we won't see each other for a month.
29:35
I'll leave you to figure that one out. But
29:37
yeah, go online to our website and, uh, send
29:40
your questions through the Ask me Anything
29:42
Anything tab. Uh, that is
29:43
spacenutspodcast.com or
29:46
spacenuts IO.
29:48
And Fred Watson, we'll see you real soon or
29:51
in a month. Whichever comes second or first.
29:54
Professor Fred Watson: Whichever. Whichever. Is time dilated?
29:56
Yes.
29:57
Andrew Dunkley: I'll tell you about our travels when, when I
29:59
get back next week.
30:00
Professor Fred Watson: I'm looking forward. I'm looking forward to
30:02
hearing that. Yes. Thanks,
30:05
Fred Watson.
30:05
Andrew Dunkley: We'll see you soon.
30:06
Professor Fred Watson: Cheers for now. Bye.
30:08
Andrew Dunkley: And, uh, thank you.
30:09
Professor Fred Watson: Thanks.
30:10
Andrew Dunkley: Yeah, thanks, Fred Watson.
30:11
Yeah, I appreciate it. It's gonna be a long
30:12
haul. Uh, and thanks to Huw in the studio.
30:15
Uh, you're gonna love this one, Fred Watson.
30:16
Uh, Huw couldn't be with us today. He, ah,
30:19
was ejected from our galaxy.
30:21
Wait for it. Because he's lactose
30:24
intolerant. Uh, you
30:26
gotta think about it.
30:28
Professor Fred Watson: But I get it. I get it.
30:30
Andrew Dunkley: I like that one. And from me, Andrew Dunkley.
30:33
Thanks for your company. We'll see you on the
30:34
next episode of Space Nuts. Bye. Bye.
30:38
You've been listening to the Space Nuts Po.
30:42
Available at Apple Podcasts, Spotify,
30:45
iHeartRadio or your favourite podcast
30:48
player. You can also stream on demand at
30:50
bytes.
30:51
Professor Fred Watson: Com. This has been another quality podcast
30:54
production from Bytes. Com. Um.