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The Starless Galaxy That Shouldn’t Exist - But Does · Space Nuts: Astronomy Insights & Cosmic Discoveries

0:00
Andrew Dunkley: Hi there. Thanks for joining us. This is
0:02
Space Nuts. My name is Andrew Dunkley, your
0:04
host, and it is good to have your company as
0:06
always. Uh, coming up on this
0:09
episode, uh, we're going to revisit the
0:12
Spanish eclipse. Because the man of the
0:14
moment, the man who went there and pointed it
0:16
out to everyone and said, that's what an
0:18
eclipse looks like, he couldn't join us, but
0:20
Fred Watson Watson will talk about it. Uh,
0:23
we'll also be, uh, discussing the Nancy,
0:26
um, Roman, uh,
0:28
observatory launch, which I watched online
0:31
the other. The other night, which was
0:33
spectacular. Uh, and there's a
0:36
galaxy that they're looking at with, um,
0:39
a bit of a frown and a scratch of the neck
0:41
because, uh, it does not appear to have
0:44
many stars. Uh, it's not emitting starlight.
0:46
How could that be? And we'll finish
0:49
up with the Mystery Clouds of Venus. That's
0:52
all coming up on this episode of space nuts.
0:55
Professor Fred Watson: 15 seconds. Guidance is internal.
0:58
10, 9. Ignition
1:00
sequence start.
1:02
Professor Fred Watson: Space nuts.
1:02
Professor Fred Watson: 5, 4, 3. 2. 1. 2, 3, 4,
1:05
5, 5, 4, 3, 2, 1.
1:07
Andrew Dunkley: Space nuts.
1:09
Professor Fred Watson: Astronauts report it feels good.
1:12
Andrew Dunkley: And he's back. After travelling halfway
1:14
around the world and, uh, returning and then
1:16
getting his leg amputated. Um, well, not
1:19
quite, but, uh, he got it rebuilt. $6
1:22
million. It was, I think the price of that
1:24
it. Professor Fred Watson Watson, astronomer
1:26
at large.
1:27
Professor Fred Watson: Hello, Fred Watson. Hi, Andrew. Thank you for
1:29
that great intro. Yes, $6 million.
1:32
Um, and, um, my health fund, um, provided
1:34
$42.5, so.
1:36
Andrew Dunkley: Yes, that's, uh, usually how it goes in
1:38
Australia. That's the going rate. No matter
1:40
what it costs you to go and see a doctor, you
1:42
get 40 bucks back. Yeah, it's a
1:45
great system. Um, yeah. Anyway, we
1:48
won't go there. That's politics.
1:50
Professor Fred Watson: That's right.
1:51
But as you alluded, uh, I have indeed
1:53
received a new knee. So I had a.
1:56
My second TKR total knee
1:59
replacement. Wow. Um, which is, uh, it was a
2:02
week ago. Yesterday was the surgery. So I'm
2:05
still on painkillers, so. Will not make any
2:07
sense whatsoever. Um, I might go to sleep
2:09
halfway through the show. That's been one of
2:11
the symptoms.
2:13
Andrew Dunkley: Well, between you falling asleep and me
2:16
sneezing, it should be an interesting show.
2:18
Hay fever is running right.
2:21
And I cannot control it. Um,
2:25
I know there's medications out there, but I'm
2:26
gonna let some. I'm not allowed to take
2:28
anymore because of my eyes. So, uh, it's made
2:31
it more complicated. So, um, I'm, I'm. I'm
2:34
well armed. Look, I've got.
2:36
Professor Fred Watson: Oh, yes.
2:37
Andrew Dunkley: The mandatory box of tissues within arm's
2:39
length. So hopefully we'll get through it.
2:42
Fred Watson. And, um, I'm glad the knee
2:43
operation went well. You're the second person
2:45
in a week that I've met who's had a total
2:48
knee replacement. A friend of mine,
2:51
um, literally stepped into a hole that he
2:53
didn't know was there because it was full of
2:54
grass and buckled his knee and the damage
2:57
was too severe and they had to do a knee
2:59
replacement. It's a bit of a shocker, that
3:01
one. Yes, but he's still on
3:04
crutches.
3:06
Professor Fred Watson: Okay, well, I've parked my crutches, although
3:08
I did resort to one in the middle of the
3:11
night. Uh, when I had to get up. I, uh,
3:13
thought, no, I'm just going to use the
3:14
crotch. But, yeah, um, it doesn't take
3:17
long. But, um, you know, your
3:20
colleague, uh, uh, there, he
3:23
had much more than just a knee replacement
3:25
with that accident damage. Mine was just a
3:28
quick one out, one in. Uh, and
3:31
so I think it's a lot more predictable and
3:33
probably a lot easier for me to recover. Um,
3:36
I'm sorry, he's still on crutches and hoopi.
3:38
I wish him well. Yes, we used to speak on the
3:41
radio a long time ago.
3:42
Andrew Dunkley: That's right. One of my old radio mates.
3:45
Uh, Fred Watson, let's talk about the Spanish
3:47
eclipse. I saw a lot of pictures and footage
3:49
online. People getting very artistic with
3:52
their photography at times. These
3:55
things have become very popular. And,
3:58
uh, from what I could tell, it was. It was a
4:00
little bit different because it wasn't sort
4:02
of up there, it was over there. Is that how
4:05
it went? It was more on the horizon than
4:08
you'd normally expect.
4:09
Professor Fred Watson: That's right. And that was always the
4:12
issue for us, uh, because at the time of
4:15
totality it was only 9 degrees above
4:18
the western horizon, and that's very low
4:21
down. Um, but we
4:23
figured that we would take that risk.
4:27
The storey actually goes back a long way.
4:30
So we were leading a tour group. We had,
4:33
uh, uh, 16 of us through France and
4:36
Spain and Switzerland. We went to the Large
4:38
Hadron Collider. We went to two observatories
4:40
in France, uh, Haute Provence and Pic du
4:42
Midi, both of which were sensational. We
4:44
really enjoyed those visits and wound up at
4:47
Santander in northern Spain. Uh,
4:50
we got there, I think, three days before
4:53
the eclipse. Um, and the first thing
4:56
Marnie and I did was to basically
5:00
stake out where we were going to watch it
5:02
from. Um, because, um, in those
5:04
resorts in northern Spain on the coast, uh,
5:07
they're all built facing eastwards because
5:10
they get the morning sun and often there is
5:12
high ground behind them. And so we,
5:15
um, found a spot about two kilometres from
5:18
our hotel. We had a couple of vehicles so we
5:20
could, and manipulate everything. Um,
5:23
Marnie, um, bought a gazebo,
5:26
uh, which we erected on our chosen
5:29
spot. There was nobody there at that time,
5:31
but we knew it was going to fill up. Uh, so
5:34
we had this gazebo. Um, we, the first night
5:37
I said, this is going to blow away if we just
5:40
leave it here. So, so we parked one
5:42
of our vehicles under the gazebo and tied the
5:45
gazebo down onto the roof of the car.
5:47
Andrew Dunkley: Oh, great idea.
5:48
Professor Fred Watson: It's still there the next day. Yeah, yeah,
5:50
until the next time, we said.
5:51
Andrew Dunkley: But the gazebo was.
5:54
Professor Fred Watson: So, yeah, it turned into, uh, quite a big
5:56
event. There were, there were very big crowds
5:59
there. We'd obviously chosen exactly the
6:01
right spot. Lots, um, of people, an ice
6:04
cream van was there. That turned up on day
6:06
two.
6:07
Andrew Dunkley: Oh, wow.
6:08
Professor Fred Watson: Uh, day T minus one, Um, a whole lot
6:11
of cops came on horseback and in vehicles and
6:13
in helicopters. They were obviously all taken
6:16
completely by surprise by this event.
6:18
What's going on up there? Um, but
6:21
yes, on the afternoon. So it was an evening
6:23
eclipse, the afternoon, uh, the sky was
6:26
completely clear. But, uh, towards the end of
6:29
the afternoon, this bank of cloud appeared in
6:31
the west. Uh, and you could see that it
6:34
was sort of spreading upwards as it
6:37
approached. So the sun was effectively
6:40
setting into that. The partial phase started
6:41
at half past seven. I spotted that
6:44
with the binoculars. It was a magical moment
6:47
when I first saw the mountains of the moon
6:48
just encroaching into the sun's disc. This
6:51
was with, uh, binoculars, with filters. Uh,
6:53
and then we. You know, eclipses are an
6:56
amazing spectacle. You've got this buildup
6:59
over an hour or so as the moon's disc
7:01
gradually covers the sun, and then that time
7:03
of perfection when the two are exactly
7:06
aligned. So what happened? We all got
7:07
steadily more and more depressed as the sun
7:09
was sinking into this bank of cloud. But
7:13
about two minutes before totality, a hole
7:16
opened up, uh, right where the sun was.
7:18
And when the total eclipse happened, we got a
7:21
perfect view of the corona. It was just
7:23
magical. It was clear. Um,
7:25
so we could see the outer atmosphere of the
7:28
sun, the corona. It looked slightly yellowish
7:30
and that's because the sun was so low.
7:32
Normally pure white and
7:35
pink clouds of hydrogen, which were bigger
7:37
than I've seen before. They were spectacular.
7:39
Lots of cheers from the crowd. There were
7:41
about 2,000 people there by then. Uh, we, in
7:44
our little uh, tent. There were 20 of us too,
7:46
because two members of my UK family, or four
7:48
members came out to watch. So, uh, a good
7:51
time was had by all. Uh, and we were
7:53
delighted to get a great eclipse. And I think
7:56
everybody was very happy. Nani and I spent
7:58
the next day.
8:00
Andrew Dunkley: I was going to say, isn't that twice in a row
8:01
that you've been to an eclipse that was
8:03
cloudy and it cleared up at the last second?
8:04
Professor Fred Watson: Cleared up, that's right. Um, not nearly
8:07
twice in a row. It was the one before last, I
8:09
think was.
8:10
Professor Fred Watson: Uh.
8:11
Professor Fred Watson: Nor was it the last one. Yes, it was the last
8:13
one. It was in Texas. That's right. And it
8:16
was cloudy. Uh, and then the holes
8:19
appeared and we saw the eclipse. So,
8:22
yeah, somebody's looking after us. I don't
8:24
know who it is. Indeed. It was great.
8:27
Um, yeah. And that sort of wrapped up the
8:29
tour.
8:29
Then we had a couple of days. Uh, we had.
8:32
Bore you with the details. We had a nightmare
8:34
journey home which involved
8:37
rebooking flights, uh, two hours before they
8:40
left through to Sydney from Barcelona. But
8:43
anyway, that's another storey. Travellers
8:45
tales. You've got plenty of them as well.
8:47
Andrew Dunkley: Yeah, yeah, yeah. Um,
8:50
I guess the difference with that eclipse in
8:52
Spain was it was happening at sunset.
8:55
And normally when you watch one of these
8:57
eclipses, it turns, uh, day into night
9:00
and then it comes back to day again, but at
9:03
sunset, I guess you sort of missed out on
9:05
that kind of effect to a certain degree.
9:07
Professor Fred Watson: Yeah. Excuse me. To a certain extent.
9:10
But it got dark very quickly, as it does.
9:13
It's only when something like 80 or
9:15
90% of the sun's disc is covered. That's the
9:18
only time when you notice that things are
9:20
dimming. Um, I think birds did go to
9:23
sleep. We didn't really take much notice. It
9:25
was 1 minute and 3 seconds was the time m of
9:28
totality that we had. Uh, um.
9:30
But yes, it did get light again. Uh. Uh,
9:33
light enough for us to take lots of
9:35
photographs of each other and all the rest of
9:37
it. Uh, we demolished the gazebo, gave it
9:39
to a guy, a French guy, who thought it was
9:42
the bee's knees. He. He had a camper van next
9:44
door. We also gave him the inflatable
9:47
fridge that we bought.
9:48
Andrew Dunkley: Oh, my goodness.
9:49
Professor Fred Watson: Did you know there was such a thing?
9:51
Andrew Dunkley: I'd never heard of it.
9:52
Professor Fred Watson: My wife does. Uh, we had an inflatable fridge
9:55
and we gave him some chairs as well, because
9:57
we couldn't take all this stuff back to
9:59
Australia.
9:59
Andrew Dunkley: Yeah, of course.
10:00
Professor Fred Watson: Yeah.
10:01
Andrew Dunkley: Fantastic.
10:02
Professor Fred Watson: Yeah.
10:03
Andrew Dunkley: Well, you know, I'm all set for, uh,
10:05
Dubbo 2028.
10:07
Professor Fred Watson: Yeah, 2028, that's right.
10:09
Andrew Dunkley: So less than two years now, not far.
10:12
We've just been sitting on this one for 20
10:14
years when we first found out about it. But,
10:16
uh, yeah, looking forward to that. In fact,
10:18
uh, I think that year, um, there's going to
10:21
be three or four eclipses in our part of the
10:23
world or over those next couple years.
10:25
Professor Fred Watson: Over the next few years, yeah, I think till
10:28
20, 30 something. I can't
10:31
remember what it is. Yeah, I don't know.
10:34
There are another three that'.
10:36
Andrew Dunkley: Yeah, okay, uh, well, that sounds like fun.
10:39
Let's talk about something else
10:40
extraordinary. Uh, the other night I was
10:42
sitting, uh, in my lounge, just about to pop
10:45
off to sleep and my brain said, you know,
10:47
they should be launching the Nancy Roman
10:49
telescope sometime soon, Andrew.
10:51
Professor Fred Watson: So I thought, oh, yeah, yeah.
10:52
Andrew Dunkley: So I grabbed my iPad and I logged on and sure
10:55
enough, the countdown was five minutes from
10:58
launch.
10:58
Professor Fred Watson: And I thought, brilliant.
10:59
Andrew Dunkley: Isn't the brain an amazing thing? Yeah,
11:02
that it, that it reminded me of that five
11:04
minutes before the launch and I, uh,
11:07
I was oblivious to it at that moment,
11:10
so I watched the whole thing. It was
11:12
fantastic.
11:13
Professor Fred Watson: Yeah, I watched the replay the next day. I
11:16
wasn't, um, switched on as you were. I was
11:18
probably asleep actually with
11:21
the painkillers. But yes, I did,
11:24
um, realise that, uh, it was taking place
11:26
then, uh, and yeah, flawless launch. It
11:28
looked fantastic.
11:29
Andrew Dunkley: Oh, it was, wasn't it?
11:30
Professor Fred Watson: Um, all 27 of those Merlin motors
11:32
firing away there
11:35
Andrew Dunkley: and it now makes the 1 million,
11:39
is it kilometres or
11:40
Professor Fred Watson: miles journey to, uh, Yes, a million
11:43
miles. A million and a half kilometres. Uh,
11:45
yeah, and I think it's well on the way, this
11:47
is to the L2 point, that point
11:49
on the far side of the Earth, uh, from the
11:52
sun where there's this stable gravitational
11:55
thing which we call a Lagrange point. Um,
11:57
several spacecraft there already, including
11:59
the James Webb and Gaia, Um, that
12:02
European, fantastic European project, that's
12:04
there a few other ones.
12:05
Andrew Dunkley: I'll be running out of room up there. They'll
12:07
have to put in traffic lights.
12:09
Professor Fred Watson: So it's interesting, um, you kind of think of
12:11
that. Oh, if this is a stable point, they
12:13
must always trying to get to the same point.
12:14
But actually what they are, they're all in
12:17
orbit around a stable point. So you're in
12:19
orbit around nothing. Um, but the
12:22
gravitational forces work to sort of keep you
12:25
in orbit there. Um, yep.
12:27
So it's, um. Yes. So
12:30
I don't know, I haven't really looked at the
12:33
commissioning schedule for the Nancy Grace
12:36
Roman. Uh, but, um, it's probably already
12:39
started because, uh, they don't waste much
12:41
time with these things to get as much data as
12:44
they can just in case something catastrophic
12:46
goes wrong early on. Um, what
12:49
we've got here is a Hubble class telescope.
12:52
Um, same sort of size as The Hubble,
12:55
uh, 2.4 metres, with,
12:58
uh, the big difference that
13:01
even though it's got the fine detail, the
13:03
resolving power of the Hubble, it's got a
13:06
hundred times the field of view of the
13:08
Hubble, which means it sees 100
13:11
times more sky. And so, you know, the
13:13
Hubble's always been giving us these,
13:16
what you might call pinhole images, just, um,
13:19
almost looking through a straw at the sky.
13:22
Uh, the Nancy Grace Roman is a wide angle
13:24
telescope. It's also infrared. Uh, so, um,
13:27
it is actually seeing redder than red
13:30
light. And we've got high hopes for what it
13:32
might achieve with huge galaxy
13:35
surveys which hopefully will show light on,
13:38
which shed light on dark matter and dark
13:41
energy. And, um, also
13:44
it's got a very sophisticated
13:46
coronagraph on board. And a coronagraph
13:49
is a thing that blots out the light of a star
13:51
so you can look for other objects nearby.
13:54
And so we should start seeing images of
13:57
exoplanets coming from Nancy Grace Roman as
14:00
well. So it is lots to talk about down the
14:02
track, Andrew.
14:02
Andrew Dunkley: Yeah, very exciting. When do they expect it
14:05
to actually be ready to roll? It's a bit
14:08
of a process, isn't it?
14:10
Professor Fred Watson: It is, that's right. I'm not sure what the
14:11
schedule is, as I was saying, but, um, we'll
14:14
keep, um, we'll keep space notes listeners
14:16
posted at the moment. The news is all good
14:18
and.
14:19
Andrew Dunkley: Yeah, it is, it is. In fact,
14:22
um, I'm just looking,
14:25
yeah, first observations, maybe early
14:28
next year sometime.
14:29
Professor Fred Watson: Yeah, they haven't got it in mind. It was
14:32
2027.
14:33
Andrew Dunkley: Yeah.
14:33
Professor Fred Watson: Um, and I mean I, I remember because
14:36
we lived it in real time. The commissioning
14:39
for the Hubble telescope back in
14:41
1990. I was an astronomer at the UK Schmidt
14:44
telescope then and we were getting direct
14:46
reports from NASA actually about the
14:48
commissioning before the Interweb. Um,
14:52
and we very quickly realised that
14:55
something was wrong because we got, um,
14:57
reports of the image diameter as they went
15:01
and the image diameter never got small. So it
15:03
was quite obvious very early on that there
15:06
was a problem with the Hubble and of course
15:09
took them three years to build a, a
15:11
little device to correct for that. And, uh,
15:14
then it was flown on a space shuttle mission
15:16
and the rest is History. Yeah.
15:19
Andrew Dunkley: A PUFU valve, I think it was, they needed to
15:22
put on it. Yeah.
15:24
Professor Fred Watson: M. Anyway, it did have a cost bar. Was it
15:26
something like that?
15:27
Andrew Dunkley: Something like that, yeah. It was lucky that
15:30
it was close enough to get to, um.
15:32
Professor Fred Watson: Yes, that's right.
15:33
Andrew Dunkley: Can't do that with the L2.
15:35
Professor Fred Watson: You can't. That's exactly right. Um,
15:38
yes, things have moved on a bit since then.
15:41
Andrew Dunkley: They have, uh, exciting times. And we will
15:44
watch with interest. And of course, uh, when
15:46
they achieve first light and we start to see
15:49
some other images, we will share them with
15:51
you here on Space Nuts. And you are
15:54
listening to the latest edition with Andrew
15:56
Dunkley and Professor Fred Watson Watson.
16:00
Professor Fred Watson: I think we need to do a little more all
16:02
weather testing.
16:04
Professor Fred Watson: Amen, Space Nuts.
16:06
Andrew Dunkley: Okay, Fred Watson, let's talk about this
16:09
strange galaxy. Um, some
16:12
are saying it's a failed galaxy. Uh, it's
16:14
been described as a starless galaxy. And it's
16:16
got a name. It's called Cloud 9. What is this
16:19
thing?
16:21
Professor Fred Watson: Uh, it's, um. Yes, it's
16:25
not a mystery galaxy in the sense that people
16:28
have speculated that there
16:31
may be galaxies without stars. And,
16:34
you know, we tend to think of galaxies as
16:37
being made of stars. Yes, ours is.
16:40
Milky Way is a gigantic spiral of stars
16:43
and gas and dust. Very beautiful. If
16:46
we could see it from the outside, which sadly
16:47
we, we never can. Uh, but,
16:50
um, it has always been
16:53
speculated that there may be,
16:56
uh, galaxies which
16:58
contain clouds of hydrogen, the raw material
17:01
of stars, which
17:04
basically is too hot for
17:07
the clouds to collapse into individual stars.
17:10
I think I've got the logic the right way
17:12
there. Yeah. So you've got the raw
17:15
material of stars, but,
17:18
um, it doesn't form a stellar
17:20
population. Um, and
17:24
maybe, um, it's because there's,
17:27
you know, as I said, the gas is too hot.
17:29
So this particular object, Cloud 9,
17:32
it's not very far away. Uh, it
17:35
is about 14 million light years away,
17:39
which puts it really on our galactic
17:41
doorstep. Uh, it's not far from a, uh,
17:44
spiral galaxy called Messier 94,
17:47
which is a lovely spiral, uh,
17:50
if I remember rightly, in the Northern
17:51
Hemisphere sky. Uh, well, it must be because
17:54
it's being observed by a telescope that, um,
17:56
I never really had anything to do with. But I
17:59
knew its sight well because it was built on a
18:01
place where I used to observe a lot. Uh, this
18:03
is the Gran Telescopio Canarias,
18:06
uh, which is the Big Canarian
18:09
Telescope. It's actually the biggest optical
18:11
telescope in the world. It has a 10 metre
18:12
mirror, um, and it's
18:15
located, uh, In La Palma
18:18
in the Canary Islands. And I used to observe
18:20
there on a telescope called the William
18:21
Herschel Telescope. So uh, gtc as
18:24
it's called, Grand Telescopio Canarias has
18:27
a camera, um, ah, called
18:30
Hypercam, ah, which is the
18:32
one that I think has
18:35
really given us this research on Cloud nine
18:38
because uh, the colleagues who
18:41
observed uh, this object, what they did
18:44
was they used that big telescope with its um,
18:47
wide angle camera in order
18:50
to get very, very deep
18:53
images. And by deep images we mean ones that
18:55
penetrate to the, at really faint levels.
18:58
Uh, they got 2.36 hours of
19:00
integration, uh, which is um,
19:04
quite, quite a long time, uh, and
19:06
didn't see any stars. I think they, they
19:09
think they might have seen a small number of
19:12
stars but not uh,
19:15
what we expect in a galaxy. Um,
19:19
so the uh, one of the authors of
19:22
this paper, um,
19:24
basically in offering an explanation as to
19:27
how you could have a galaxy with no stars,
19:30
uh, I'll quote. The leading theoretical
19:32
explanation involves the ultraviolet
19:35
background radiation that permeates the
19:37
universe after the epoch of
19:39
reionization. Uh, that's right at the
19:42
beginning, this radiation field heats the gas
19:44
in low mass dark matter halos to
19:46
temperatures high enough that the gas cannot
19:49
cool efficiency and collapse to form stars. I
19:52
think that might be what I said earlier,
19:53
which is good. Um, when they do
19:56
simulations um, of
19:59
uh, you know, basically what this galaxy,
20:02
how it might have evolved, sure enough it
20:04
remains starless. They don't have any stars.
20:06
So this looks like uh,
20:09
look like, looks uh, like ah, the first real
20:12
example of something that people have
20:15
thought must exist. Um, and
20:18
again quoting from. It's Dr.
20:20
Trujillo, who I think I might have worked
20:23
with in La Palma many, many years ago.
20:26
Uh, says Cloud 9 has a halo mass
20:29
consistent with this regime. In this picture,
20:31
starless galaxies are not
20:34
exotic anomalies, but a natural and
20:37
abundant prediction of standard
20:39
cosmological models. The challenge has simply
20:41
been finding them. So uh, maybe it's
20:44
not such an unusual thing after all, uh,
20:47
but uh, something that uh, has been
20:50
predicted. But yes, the first, I think the
20:53
first one that we can really be sure, uh, is
20:56
a starless galaxy.
20:58
Andrew Dunkley: Yeah, very, very unusual. Um, I'd
21:01
suppose the description failed galaxy would
21:03
be probably accurate given
21:06
the circumstances.
21:07
Professor Fred Watson: Yes, if you think of a normal galaxy as
21:10
being populated by stars, it is.
21:13
Um, but you can see that there's good reason
21:16
for it to fail if the temperature of the
21:18
background gas and the dark matter that's in
21:20
it are too high for stars to form.
21:24
Um, and you might consider It a success
21:26
because it's a purely gaseous
21:29
galaxy.
21:30
Andrew Dunkley: Yeah, yeah. Uh, I suppose one
21:33
day it might merge with another galaxy and
21:35
then, you know, all hell will break loose.
21:39
Professor Fred Watson: No, you're right, that's a good point because
21:41
it's not that far from M94, which is a big
21:43
galaxy. Uh, this is a, it
21:46
counts as a dwarf galaxy. I didn't really
21:48
make that clear. And of course our
21:51
own galaxy has dwarf galaxies in orbit around
21:54
it, most of which contain stars. Uh,
21:56
and so, and the fate of those dwarf galaxies
21:59
is basically to become part of the, of the
22:02
bigger galaxy. So it may be that Cloud nine
22:05
eventually does that and maybe the conditions
22:08
will change so that the, the gas becomes,
22:11
um, uh, cool enough or
22:13
otherwise relaxed enough, uh, in order to
22:16
start and form stars.
22:18
Andrew Dunkley: Okay. If you want to, uh, read all about the
22:20
Starless Galaxy Cloud 9, there's a great
22:23
article on Space dot com.
22:26
Um, Fred Watson, we've got a live viewer
22:29
who has, is from Dubbo, actually. Hi,
22:31
Lynette. Um, she says, uh,
22:34
hello from Dubbo. How long did you stay. I
22:36
assume she means Spain. Um,
22:40
from her earlier conversations.
22:41
Professor Fred Watson: Yes, we were in Spain for, uh, roughly
22:44
a week actually. Uh, I didn't tell you, but
22:47
I, I got, um, I got,
22:50
um, thieved from by a pickpocket.
22:54
Professor Fred Watson: Oh.
22:55
Professor Fred Watson: Yeah.
22:56
Andrew Dunkley: Um, but very, very common thing over there.
22:59
Professor Fred Watson: It was in Bilberryo and. Oh, we went
23:01
there. Lovely place. Did you get your
23:04
binoculars nicked as well?
23:05
Andrew Dunkley: No, no, I, I'm very, very,
23:09
um. We'll
23:12
use the word anal about holding on to my
23:15
stuff, quite literally.
23:16
Professor Fred Watson: Yep.
23:16
Andrew Dunkley: I put stuff in my pockets and I'll shove my
23:18
hands in my pockets and I will not take them
23:20
out. Yeah, I must look weird.
23:24
Professor Fred Watson: Well, you look weird anyway, Andrew, but
23:25
that's, you know, not good. Not bad news
23:28
anyway. Uh, but, but no, you're right. Um,
23:31
so I'm like that too. But, um, I, I
23:34
had a sort of man bag. Um,
23:37
and um, I was walking back
23:40
from the Guggenheim exhibition, which you
23:43
probably went to see as well, in Bilberry, to
23:45
our hotel, and I thought
23:48
I noticed a bit of a disturbance
23:51
behind me. I had headphones on. Um, noise
23:53
cancelling headphones because I was walking.
23:55
Andrew Dunkley: Yeah.
23:56
Professor Fred Watson: And um, when I got into the hotel, I looked
23:58
in my man bag and the zip was open
24:01
and I know I, I shut it up and my
24:04
binoculars were missing. So Marnie said
24:07
go outside and have a look. They might have
24:09
thrown them away. So went outside.
24:13
Here's four policemen bailing up these two
24:15
guys
24:18
and they've Been. They've been following them
24:20
because they'd created some sort of problems
24:22
in a bar. Um, and I approached
24:25
one of the policemen and said,
24:27
um, I've, uh, lost a pair of binoculars.
24:30
And he just said, yeah, we've got your
24:31
binoculars. Wow. So I got lucky.
24:35
Fantastic.
24:38
Yeah, these guys had tried to throw them away
24:40
when they saw the police were on them and the
24:43
cops had seen it. The cop who dealt
24:46
with me spoke great English. He was an
24:49
absolute gentleman. It was, uh, such a good
24:51
experience that Marnie insisted on taking
24:53
our, uh, photographs together and things like
24:55
that afterwards.
24:56
Andrew Dunkley: Well, you got very lucky, Fred Watson. Very
24:58
lucky.
24:59
Professor Fred Watson: Very, very lucky indeed. Yeah, absolutely
25:01
lucky. Uh, I couldn't believe it. And
25:03
actually, those, uh. You know, I can go on
25:06
about binoculars ad. Uh, infinitum. M. Having
25:08
written the first book in English on the
25:10
history of binoculars. Uh, but they were a
25:13
special pair as well. Quite new. They're new
25:15
to me. They're, um. Basically, they
25:18
were made in the 60s. Sorry, the. The 70s.
25:21
But they're very, very good ones. And, um,
25:23
yeah, they're worth a lot of money.
25:25
Andrew Dunkley: So Starchild says, um, we've got a few live,
25:28
uh, viewers at the moment. And Starchild
25:30
says, quite a few thieves in the Milky Way.
25:34
Professor Fred Watson: Yes, that's right, yeah.
25:36
Andrew Dunkley: Um, and there was another
25:38
question. Uh, uh, good. Uh, says, good to see
25:41
you two together again. Moose says, how much
25:43
did I miss? Uh, about that much.
25:47
I think we're a bit past halfway, Moose. And,
25:49
um, another question. Um, how
25:52
many light years across is a dwarf galaxy? I
25:55
guess they're all different sizes.
25:57
Professor Fred Watson: They are, but it's a good question. I mean,
25:59
um, so think of our galaxy, which is
26:02
kind of 100,000 light years across.
26:05
Um, and that's typical of
26:07
a. Of a major spiral galaxy.
26:10
Dwarf galaxy would probably be
26:13
less than a tenth of that. Um, 10,000
26:16
light years. That sort of size. You know,
26:18
just on. On average. Uh, that kind of.
26:21
That kind of size.
26:23
Andrew Dunkley: Okay. Thanks for the question. It doesn't
26:25
happen like this very often, but today
26:28
we've got an active audience. That's good.
26:32
Yeah. All right. Uh, you're listening to
26:34
Space Nuts, by the way, uh, with Andrew
26:36
Dunkley and Professor Fred Watson Watson.
26:40
Professor Fred Watson: Okay, we checked all four systems.
26:43
Andrew Dunkley: Space Nuts, our final topic. Fred Watson
26:46
takes us to Venus. Sunny Venus.
26:49
Ah, yes. What a place. Go outside, take a
26:51
deep breath, drop dead. Um, but
26:54
there's some news about Venus which involves
26:56
its clouds again. Now, the last time this was
26:59
big news was when they thought they might
27:00
have found, um, signs of life in the
27:03
clouds. That's still under a lot of
27:05
speculation and debate. But, uh, what's the
27:08
latest with these clouds? These aren't the
27:11
ones we were talking about last time. These
27:13
are a little bit different again.
27:15
Professor Fred Watson: Yes, they are, yeah. So I think that was
27:17
sulphur. Was it sulphur dioxide? I can't
27:19
remember. Um, the detection, uh, which
27:22
people got excited because it might mean
27:24
living organisms in the upper atmosphere of
27:26
Venus. But I think that's gone away now.
27:29
Um, it's great to talk about Venus,
27:31
especially just now, because you would know,
27:33
Andrew, it's absolutely lighting up the
27:35
evening sky. Uh, over there in the west. It
27:38
is very bright, very high in the sky,
27:41
beautiful object. And when we look at it,
27:44
it's kind of got a yellowish colour, uh,
27:47
which is because we're seeing reflections
27:49
from the top of its cloud layer.
27:52
Um, but, uh, it's been known
27:55
for a long time that
27:58
if you photograph Venus in with
28:00
ultraviolet light, you. You
28:03
see patterns, really
28:06
dramatic patterns. And I've, uh, got one in
28:08
front of me now. But I do remember
28:10
photographs of this, that these are sort of
28:12
global size patterns that actually
28:15
move, uh, with the. The
28:17
clouds of Venus. Uh, we
28:20
know. I think most space notes, uh,
28:23
listeners and viewers would know that we
28:24
don't actually see the surface of Venus
28:26
directly. We can with radar, uh, certain
28:29
infrared observations that let you penetrate
28:31
to the surface. But basically all we see, uh,
28:34
and certainly in ultraviolet is the upper
28:36
parts of the cloud belts, cloud
28:39
layers. So the markings themselves,
28:42
uh, are a puzzle. And,
28:45
and this is where it sort of gets
28:47
interesting. Although it's not one of these
28:49
storeys that's got a neat and tidy answer,
28:51
I'm afraid. Um, there's a
28:53
chemical that is thought to be in
28:56
Venus's upper atmosphere, which is
28:59
called the unknown absorber.
29:02
Uh, and because, uh, it absorbs
29:05
light in the ultraviolet and you get dark
29:08
patches from. From this, this stuff.
29:11
Um, I was talking to somebody about this the
29:14
other day and they said it sounds like a
29:15
superhero, the Unknown absorber. Uh,
29:18
which, uh, I think probably would work well.
29:20
Andrew Dunkley: Yeah, his superhero name would
29:23
be the Sponge.
29:25
Professor Fred Watson: The Sponge, that's right.
29:28
So what's happened is that,
29:31
um, a team, an international team
29:34
actually, of basically astrobiologists,
29:36
people who were looking at,
29:39
uh, the origin of life in the universe
29:42
and what we need for life to form and all of
29:44
those other good things, not necessarily
29:46
trying to find life, but trying to understand
29:48
life. Um, what they've done, uh,
29:51
they've essentially this
29:53
research team, I think they've done very
29:57
cluey kind of modelling, um,
29:59
of the droplets within the
30:02
clouds of Venus to try and
30:06
not identify what this unknown absorber
30:09
is, but sort of, um,
30:12
place limits on its properties. You
30:15
know, it does this but it doesn't do that.
30:17
Uh, and it does this to this extent, but it
30:19
doesn't do that to this extent. So, uh,
30:22
it's all about trying to model what
30:25
cloud droplets would look like to
30:27
actually reproduce what we see when we
30:30
observe the planet. Um,
30:34
so, uh, uh, one of the
30:37
authors of the paper basically
30:40
poses a question, uh, if
30:43
we were to collect Venus's cloud
30:45
droplets, and I'm paraphrasing here,
30:48
into a bucket, how would the
30:50
reformed bulk liquid appear? Uh,
30:54
the scientist actually said a spectrometric
30:56
cuvette. Uh, but a bucket's as good an
30:58
allergy for that as you need. If you could
31:01
collect the droplets, what would it look
31:03
like? Um, and that
31:06
is the sort of key
31:09
to the modelling that's been done.
31:12
Um, they, there's a comment, um,
31:15
I think it might come from the original
31:17
paper, but um, phys.org has got a very
31:20
nice article on this and I
31:22
think it may even come from their press
31:25
release. Uh, but basically it's
31:29
likening the droplets in
31:32
the clouds of Venus to cigarette smoke.
31:35
Um, because, um, cigarette smoke is
31:37
tiny particles, tarry. Tiny tarry
31:40
particles, um, which
31:43
look sort of white or bluish because of the
31:46
scattering of light. Because these things are
31:47
so small they scatter light very effectively.
31:50
But if you collected it into a flask, you
31:53
got this horrible sludge, uh, tar,
31:56
like sludge. Of course that was what ends up
31:58
in your lungs if you're a smoker. Um,
32:02
yeah. So what they're suggesting is that
32:06
there's a similar phenomenon happening in
32:08
Venus's clouds, uh, because the particle
32:11
size of the droplets in Venus's upper
32:13
atmosphere are comparable to the particle
32:16
size of cigarette smokes, smoke.
32:18
So even though, um, you know, even though
32:21
the clouds with the visible light
32:25
look that sort of yellowish colour that we've
32:28
mentioned already, the actual
32:31
droplets themselves could be really,
32:33
really dark and it's only because they
32:36
scatter the light in a certain way that they
32:37
look that they look yellowish. Um,
32:41
so this, um, basically this uh, research
32:43
is asking that question. What happened? What
32:46
would happen if you could collect a cloud of
32:48
material from the atmosphere of Venus and put
32:50
it into a, um. Basically, you
32:53
know, a flask or
32:57
um, a beaker or something like that. Um,
33:00
and that's where this analysis has
33:03
gone and they've used something, it's words
33:06
that used to strike terror into me when I was
33:08
a student in astronomy. Andrew And I don't
33:10
know whether I've uttered them ever since.
33:12
Radiative transfer. Uh, radiative
33:15
transfer is the way radiation moves around
33:18
uh, among atoms. Uh
33:21
and it's very, very intense
33:23
mathematics. So these scientists
33:26
obviously like that kind of thing. I'm afraid
33:28
I didn't. Uh, and they've built a radiat
33:31
transfer model that uh, actually lets
33:33
you um, account for not just
33:36
single scattering but multiple scattering
33:39
because you've got to um, take into account
33:41
that light might scatter from one of those
33:43
droplets and then hit another one and scatter
33:45
from that. So you've got multiple scattering
33:48
phenomena. Um and so
33:52
they uh, have basically done that
33:54
and produced what is called the
33:57
absorption coefficient of the bulk cloud
34:00
liquid. That's the, how it would absorb um,
34:03
if you just had a flask of this stuff.
34:06
Now what they're saying is that they don't
34:08
really know what this, these droplets are
34:11
but they're not suggesting it's life.
34:14
Um, they've put limits on the
34:17
absorption coefficient
34:19
um, and uh,
34:22
essentially again paraphrasing the
34:25
uh, Press release from phys.org uh the
34:28
result implies that the unknown absorber
34:31
must either absorb light very
34:33
efficiently, occur at a very
34:36
high concentration or both. Um,
34:39
my guess is it's going to be both. Um, so uh,
34:43
it's some sort of, probably some sort of
34:45
organic compound and by that I mean one that
34:48
contains carbon rather than one that contains
34:50
living organisms. Um and
34:53
they've basically you know, they've suggested
34:56
some chemicals that might actually
34:59
be, be uh, responsible for this.
35:01
Uh, excluding they say chlorophyll.
35:04
Chlorophyll of course very important in life
35:06
processes. Uh but they're excluding, they're
35:09
saying they're not proposing chlorophyll as
35:11
ah an example. So uh,
35:14
as I said it's a storey that doesn't have a
35:16
conclusion. But it's
35:19
interesting to think of the clouds of
35:21
Venus that if you could collect them in a
35:23
bucket or a container they could be very very
35:26
dark mixtures like tar, a sort of
35:29
sludge, um,
35:32
would be interesting.
35:35
Andrew Dunkley: Yeah, um, it's a
35:38
classic example of a failed Earth like world.
35:42
Professor Fred Watson: Yes, that's right. Yes indeed. We don't have
35:45
things like this in our planet thankfully.
35:49
Yeah, I think there's more um, sorry Andrew,
35:52
just to finish the storey, I think there's
35:53
more research being
35:56
designed possibly looking
35:58
uh, uh, with a
36:01
future mission to Venus, uh, perhaps
36:04
looking for fluorescence
36:07
uh, in the clouds because that would give
36:09
them another angle on what this stuff is.
36:12
Andrew Dunkley: Okay, we watch with interest. Uh,
36:16
Venus Keeps throwing up curveballs.
36:20
The potential for life in the clouds because
36:22
of the discovery of phosphine. And now this.
36:25
Um, a bucket of tar.
36:26
Yay. What a place. Next
36:29
holiday, I think.
36:31
Professor Fred Watson: Well, yeah, plus you've got the sulfuric acid
36:33
as well.
36:34
Andrew Dunkley: Oh, that's true. Yes, yes. And. And the, um,
36:36
undeniable level of heat. Uh, I think
36:38
Australians could handle it and a few other
36:40
places in the world, but most, no, most
36:42
people couldn't. It's horrible. It's an
36:44
horrible place. But very pretty in the sky at
36:47
the moment. It is. You can read all about
36:50
it@fizz.org as Fred Watson said, or you can
36:52
read the entire paper, which was published in
36:55
Astrobiology. And that brings us to
36:58
the end. Fred Watson, thank you very much.
37:01
Professor Fred Watson: Uh, it's a pleasure, Andrew. Um, it's always
37:03
good to chat and, um, even better to chat
37:05
when you're half asleep. You did
37:08
well.
37:09
Andrew Dunkley: You did well. For those who joined us late,
37:12
um, you'll have to listen to the episode, get
37:14
the full explanation of Fred Watson's
37:16
sleepiness. Um, it's got something to do
37:19
with, um, painkillers. Anyway,
37:22
we'll get on. Hopefully he'll
37:25
brighten up for the next episode.
37:26
Professor Fred Watson: I suspect not.
37:27
Andrew Dunkley: Um, thank you, Fred Watson. We'll catch you
37:29
soon, dude.
37:30
Professor Fred Watson: Sounds great. Thanks, Andrew.
37:32
Andrew Dunkley: Professor Fred Watson Watson, astronomer at
37:34
large. And don't forget to visit us at our
37:36
website between episodes, which you can
37:38
do@spacenutspodcast.com or
37:40
spacenuts IO have a look around
37:43
and, um, see what's there. The shop.
37:46
You can send us messages, you can sign up for
37:49
Astronomy AstroDailyPod. Plenty of things to
37:50
see and do. And don't forget to leave reviews
37:52
about our, uh, podcast wherever you listen to
37:54
us. And thanks to Huw in the studio, who
37:57
couldn't be with us today because he
37:58
discovered that, um, he's more at home in a
38:01
starless galaxy. And from me, Andrew Dunkley,
38:04
thanks for your company. See you on the next
38:05
episode of Space Nuts.
38:07
Professor Fred Watson: Bye.
38:07
Andrew Dunkley: Bye. You've been listening to
38:10
the Space Nuts podcast,
38:13
available at Apple Podcasts, Spotify,
38:16
iHeartRadio or your favourite podcast
38:19
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38:23
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38:25
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