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Cosmic Collapses, Black Hole Illusions & Antimatter Mysteries · Space Nuts: Astronomy Insights & Cosmic Discoveries

0:00
Andrew Dunkley: Hi there. Welcome to a Q and A edition of
0:02
Space Nuts. My name is Andrew Dunkley, your
0:05
host. Good to have your company again. Uh,
0:07
questions coming today from Pete. Uh, he's
0:10
looking at the collapse of the universe.
0:13
Wants to know where he needs to be when it
0:15
happens, so he gets a good view. Actually, I
0:17
think it's about something else. Uh, we've
0:19
also got a question from Tad, who has
0:22
brought up a really interesting point about
0:24
falling into a black hole. From an observer's
0:27
perspective. If we were to watch someone or
0:29
something do, uh, really is a.
0:33
A great piece of science to talk about. Uh,
0:36
Mark is, uh, bringing up something from an
0:38
episode four years ago, I think. Antimatter,
0:41
uh, stars. And Dave, um,
0:44
wants to know about the best time and place
0:46
to aim a camera for low, uh, light
0:49
astrophotography. Uh, that
0:52
is a great question. Uh, I've had so much
0:54
trouble with that myself. We'll get stuck
0:56
into it right now on this edition of space
0:59
nuts.
0:59
Voice Over Guy: 15 seconds. Guidance is internal.
1:02
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1:05
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1:08
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1:18
Andrew Dunkley: And here he is again. Professor Fred Watson
1:19
Astronomer at large. Hello, Fred
1:22
Professor Fred Watson: Hello, Andrew. Fancy seeing you here.
1:24
Andrew Dunkley: Yes, yes. And we're in similar coloured
1:27
shirts today.
1:27
Professor Fred Watson: That's right. I think we're very chic.
1:29
Andrew Dunkley: Judy reckons green's my colour, but I've
1:32
never really liked green. But
1:34
anyway, she's more of a
1:37
fashionista than I am, so I'll take her word
1:39
for it. Uh, how you been?
1:42
Professor Fred Watson: Very well, thank you. Yes, um, all seems to
1:45
be going well so far.
1:47
Andrew Dunkley: You look and sound as well as the last time I
1:49
saw you.
1:49
Professor Fred Watson: Well, that's right. I've, you know, uh,
1:53
it's, uh, it's. It seems like only
1:55
a few minutes ago. It does, doesn't it?
1:58
Andrew Dunkley: Funny that, um. That's because of a black
2:00
hole.
2:01
Professor Fred Watson: It could be a black bill.
2:04
Andrew Dunkley: Although we must point out that this will be
2:07
your last show for a short while. You're
2:10
taking a bit of a trip which will take, um,
2:12
you into time zones that are just not
2:14
compatible with life on Earth in Australia.
2:16
So, um, uh, we will be, uh,
2:19
bringing our, uh, stand in Jaunty Horner in
2:22
to look after things while you're away for
2:23
about 7ish weeks, something like that.
2:27
We, we knew this was going to happen this
2:30
year with me away for three months and you
2:32
away for, uh, a couple of months. So we knew
2:35
this was going to happen and we, we planned
2:37
ahead so that the show could go on. So,
2:40
um, anyway, we'll um, we'll look forward to
2:42
chatting with, with Jonty and wish, uh, you
2:45
well on your trip. Um, where.
2:49
Professor Fred Watson: We'Ve got about two and a half weeks in
2:51
Japan. Uh, then we're back in
2:54
Australia very briefly and then we're off up
2:56
to Ireland for a Dark sky conference and,
2:59
uh, skipping over to the UK to hang out
3:02
with my family for a little bit in the uk and
3:04
uh, that'll take us to the end of November.
3:07
Andrew Dunkley: Why wouldn't you? It's just a short hop,
3:09
isn't it, really?
3:09
Professor Fred Watson: Yeah, that's right. Yeah. It's stupid. Going
3:12
to uk. That's right, yeah. So we'll do
3:15
a few, uh, things. We're going to, uh.
3:17
Marnie's got a nice itinerary for us. We're
3:19
going to go to places that I have wanted to
3:21
go ever since I was a child and never made it
3:24
in the uk. So that's fantastic. We'll tell
3:26
you about it when we get back.
3:28
Andrew Dunkley: Love to hear about it. Um, we better get
3:31
into, uh, the questions.
3:33
Professor Fred Watson: Yes, yes.
3:33
Andrew Dunkley: Yeah, I guess so. Yeah. Yeah.
3:35
Our first question's an audio question
3:38
coming, uh, from Pate Fred Watson and
3:40
Andrew.
3:41
Pete: Pete from Longpoint got a question.
3:43
I know that there's
3:46
contested as to what's going to happen in the
3:49
future with the universe. The kind of
3:52
dang, or however it's pronounced, or
3:55
expansion or the Big Rip or whatever. The
3:57
question if, if the universe is going to
4:00
collapse back in itself. I get the concept
4:03
of the gravity
4:06
bringing sort of physical matter back
4:08
together and I know that's only what, 5% of
4:11
the universe, but I don't understand how
4:14
that would work with
4:17
the. Basically pulling light
4:20
backwards. So you have light is
4:22
expanding ever increasingly,
4:25
obviously at the speed of light. Um,
4:28
basically what happens with that in the event
4:31
there is a collapse back to another
4:33
singularity? Um, yeah, I'm
4:36
confused. Thanks guys.
4:39
Andrew Dunkley: I think a lot of people are, uh, um, yeah, he
4:41
was referring to the Gnab Gib, which is the
4:44
reverse Big Bang. Yeah. Uh, but it's
4:47
an interesting question because if, if it
4:49
does happen, rather than a Big Rip, uh, the,
4:52
the universe stops expanding and then starts
4:55
receding back in on itself. What does
4:58
happen to the light and the dark matter
5:01
and all that other stuff that we don't
5:03
understand.
5:05
Professor Fred Watson: So, um,
5:08
uh, this. No, thanks very much,
5:11
Pete.
5:11
Great question. Uh, which has arisen because
5:16
I, um, think it might be. While you were
5:17
away, Andrew, we covered the new
5:20
observations that have come from the dark
5:23
energy, uh, instrument, um,
5:27
which is on a, on a, on the
5:30
mail telescopes, a telescope very similar to
5:32
our Anglo Australian telescope which is uh,
5:35
which has been surveying the universe as you
5:37
do with such instruments, um, getting the
5:40
redshifts, which means the distances of all
5:42
the galaxies and building up a map. And that
5:45
map um, has just the first hint
5:48
that dark, the acceleration of the
5:50
universe which we attribute to this dark
5:53
energy, whatever it is, uh, that the
5:55
acceleration of the universe is actually
5:56
slowing down. It's still only a hint, it's
5:59
not confirmed yet. But if the acceleration
6:01
is slowing down then it does
6:05
raise once again the possibility that we
6:07
talked about a lot in the 1970s and 80s.
6:10
Uh, the idea of an eventual collapse, a
6:13
reversal of the expansion of the universe to
6:15
a collapse. Uh, and the end product of
6:18
that often called the Big Crunch. But we
6:21
like the GNAB gib. That was the name that
6:23
Brian Schmidt gave to it. It's a great name.
6:26
So what happens in the Gnab gib? Well, um,
6:30
it is interesting. You've got gravity taking
6:33
over and it doesn't just
6:36
sort of bring together
6:39
the objects in space, it doesn't just
6:42
collapse all the galaxies towards one place,
6:45
it actually collapses space time with it.
6:48
Um, because the, you know, the,
6:50
the matter bend space. We know and that
6:53
bending is effectively what you, what you
6:56
would call the collapse uh, in the run
6:59
up to the, or the run down to the Ganab gib.
7:02
And so in a sense, uh, the light,
7:05
uh, so, so what I'm saying is that
7:08
um, the, the distances that, that across
7:11
the, the distances that we measure between
7:13
galaxies becomes less. But, but
7:16
it's because the space time has shrunk
7:19
basically. Uh, and so not just that
7:22
the galaxies have got closer together.
7:25
And that means uh, that yes, light will still
7:27
continue to travel through space time at
7:30
300,000 kilometres per second, but that
7:32
space time has got less space in it.
7:35
Um, and so the light just shrinks with the
7:38
universe. It doesn't kind of escape or
7:41
anything that many gazillions
7:44
of photons that are currently traversing the
7:46
universe and will continue to do that, uh, as
7:49
long as things are shining and there's energy
7:50
to provide that they will have shorter
7:53
distances to go. Uh and we will find
7:56
that the universe just gets smaller. As it
7:58
gets smaller, the light goes with it and we
8:01
end up with a bundle of stuff, uh, subatomic
8:04
particles, including photons, particles of
8:07
light, a whole lot of stuff that is going to
8:08
hit an almighty singularity,
8:11
uh, uh, which we might call the GNAB
8:14
gib. Yeah, wow.
8:16
Andrew Dunkley: Um, correct Me if I'm wrong, but didn't
8:19
we talk in the past about a time where the
8:22
universe will become dark and
8:24
cold and there won't be
8:27
any light?
8:29
Professor Fred Watson: Well, um, that's right. If the universe
8:31
continues expanding, then eventually
8:34
there will be light there, but it won't be
8:36
able to reach you because it'll be beyond
8:38
your. Your horizon. Uh,
8:40
so, uh, the light will still be going through
8:43
the universe, but that light source will
8:46
be receding from us, um,
8:49
too fast for the light ever to get to us.
8:51
So, yes, it becomes dark and dreary. Uh, but,
8:54
yeah, light is still there.
8:55
Andrew Dunkley: Uh, all right, there you go, Pete. Um,
8:58
it will all be cataclysmic and horrible, and,
9:01
uh, we'll all be a lot shorter.
9:05
Professor Fred Watson: Every dimension.
9:06
Andrew Dunkley: Indeed, yes. Although I'm starting to like
9:09
the idea of a big rip. Because a big rip
9:11
might open us to another universe and we
9:13
could all escape.
9:15
Professor Fred Watson: Well, yeah, maybe. Well, of course, you with
9:17
the big. The gnab gib, you could get the big
9:19
bounce. Uh, you know, it could just bounce
9:22
back. So you've suddenly got an expanding
9:24
universe immediately.
9:26
Andrew Dunkley: Yeah, it's hard to get your head around. And
9:28
I understand why Pete feels confused, because
9:31
it really is beyond our imagination in many
9:34
ways, isn't it?
9:34
Professor Fred Watson: That's right.
9:36
Andrew Dunkley: Thanks, Pete. Great question. Hope you're
9:38
well.
9:38
Uh, let's go to a question from Tad.
9:41
Uh, this one's really interesting. Uh, we
9:43
understand that due to extreme gravitational
9:45
time dilation, from the perspective of an
9:48
outside observer, anyone falling into a black
9:51
hole takes an infinite amount of time to
9:54
cross the event horizon, even if, from that
9:56
person's perspective, they actually do in
9:59
real time. Uh, if this is true, how
10:02
do black holes and their event horizons even
10:04
form in the first place, from an outsider's
10:07
perspective? And does this mean that
10:09
technically nothing has ever fallen into a
10:11
black hole from our perspective here on
10:13
Earth? I love this question. Thank you, Tad.
10:17
Uh, he's bringing up the point
10:19
where if you're watching someone fall into
10:21
the. Into a black hole because of
10:25
the. The effect, the gravitational effect on
10:27
time space, it never happens,
10:30
but that person
10:32
experiences it in real time until they get
10:35
spaghettified. So, um,
10:38
yeah. How come we see black holes
10:41
when this effect should
10:44
suggest we. We should never see it happen?
10:47
Is that. Is that what I'm. Is that what he's
10:49
saying?
10:50
Professor Fred Watson: Yeah, yeah. How do black holes form in the
10:53
first place?
10:55
Andrew Dunkley: Uh.
10:57
Professor Fred Watson: So it, uh, yes. So in that regard,
11:00
that time dilation is a kind of optical
11:03
illusion because the thing has crossed the
11:05
event horizon, whatever it is. Uh, has
11:08
contributed to the mass of the black hole.
11:10
So, uh, the reality is, yes,
11:13
you're, you know, if it's you, you get
11:15
spaghettified and then you get absorbed by
11:17
the black hole itself a gazillionth of a
11:19
second later. Um, it's from the outside
11:22
perspective. Uh, I've always struggled with
11:25
this actually in trying to envisage it
11:26
because, yeah, you imagine some poor person
11:29
who's fallen into a black hole. Um,
11:32
it's be like the, um, you know those,
11:35
uh, chalk things on the road where
11:38
somebody's got hit by a car. There'd
11:40
be this chalk mark of somebody, uh, on the
11:43
surface of the event horizon.
11:46
Um, uh, but they'd
11:48
also, uh, uh, along with that person, there'd
11:51
be everything else that's gone into it. And
11:52
black holes are notorious for accreting
11:55
material. So all the stuff that's spiralling
11:56
into it from an outsider's perspective just
11:59
ends up looking as though it's stuck on the
12:01
surface of the event horizon, even though
12:03
it's actually been absorbed by the
12:06
black hole. So it is a kind of optical
12:08
illusion. Yes, it's very weird. It, uh, just
12:10
means that from, you know, what it highlights
12:13
is, uh, it's all about your
12:16
reference frame. Uh, our reference frame is
12:18
an, um, observer looking out, looking in from
12:21
the outside. If you've got the reference
12:24
frame of the person who's falling into the
12:26
black hole, things are a lot different. We,
12:28
uh, can watch, um, you know, from the
12:31
sidelines and cheer people on as they fall
12:32
through the black hole event horizon. All,
12:35
uh, we see is them frozen on the
12:38
event horizon. Uh, which must be a very messy
12:41
place with all the stuff that's falling into
12:42
it.
12:43
Andrew Dunkley: Yeah.
12:43
Professor Fred Watson: So, um, I, yeah,
12:46
I, you know, it to me, that transforms what
12:49
the event horizon might look like. It's
12:51
probably not that nice sphere of darkness
12:53
that we imagine, but it's got splattered with
12:56
lots of stuff. And in fact, we know that the
12:58
magnetism of a black hole actually plays a
13:01
huge role in, um,
13:03
directing material so that some of the stuff
13:06
is actually accelerated perpendicular to the
13:08
accretion disc, uh, backward, up, upwards
13:11
and downwards. And that in itself is a
13:14
process. It's very hard to get your head
13:16
around how stuff that's swirling in towards a
13:18
black hole suddenly gets dragged up, uh,
13:21
and shot out the poles of the
13:24
black hole, top and bottom. Um, so a
13:27
lot of hard work to conjecture. I hope that
13:30
helps Tad to envisage what's going on.
13:33
Uh, um, because it's all about your
13:35
perspective, basically.
13:37
Andrew Dunkley: Yeah, yeah. Uh, so the black hole,
13:40
uh, has happened.
13:44
My brain had an idea and it just fell into a
13:47
black hole. Now, um, I can't remember, but,
13:49
uh, we. We see the black hole
13:53
because it's already happened. Is that.
13:56
Professor Fred Watson: Well, yeah, the black. The black hole's been
13:58
created in. I mean, typically in the collapse
14:01
of a. Of a star at the end of
14:04
its life. Uh, so that's a
14:06
straightforward gravitational collapse. The
14:08
material of the star, uh, basically collapses
14:11
down so that nothing will hold it out
14:14
and it becomes this singularity, a point of
14:16
infinite density, which is how we define it.
14:19
Um, and that's. It's during that collapse
14:21
that the event horizon forms. And you've got
14:24
that. As I said, it's an optical illusion.
14:26
That's the main point to recognise. It's an
14:29
optical illusion as seen from the outside,
14:32
um, that nothing reaches a black hole.
14:35
M Mm.
14:36
Andrew Dunkley: I'm sure we'll get some more questions on
14:38
this one, but, uh, you've probably opened a
14:40
can of spaghetti there, Tad.
14:42
Professor Fred Watson: Yeah, which is great because Jonty can deal
14:44
with all of that.
14:45
Andrew Dunkley: Yes, he can. Yeah. Yes, that's for
14:48
sure.
14:48
M All right, Tad. Thank you for the question.
14:51
This is Space Nuts, a Q A edition with Andrew
14:53
Dunkley and Professor Fred Watson Watson.
14:58
Three, two, one.
15:01
Space Nuts. Now, uh, our next
15:03
question's an audio question. It comes
15:06
from Mark.
15:08
Mark: Hi, it's Mark in London and Canada.
15:11
I just listened to an episode from
15:14
March 2021 and Fred Watson mentioned the
15:17
possible existence of an antimatter
15:20
star and how. Obviously we wouldn't want to
15:23
get, uh, anywhere near it,
15:25
but I was wondering, is it. Is it possible?
15:28
Do they exist? Uh, and how could we tell if
15:31
we're looking at a star from Earth, can we
15:33
tell if it's regular matter or antimatter
15:36
or. What if the entire Andromeda Galaxy
15:39
was antimatter, would we have a way of,
15:42
uh, figuring that out?
15:44
Professor Fred Watson: Thanks.
15:44
Mark: Bye.
15:46
Andrew Dunkley: M Uh, I would ask my Auntie
15:48
Shirley, but she wouldn't know either. Um,
15:51
thank you, Mark. Antimatter stars. We did. I
15:54
remember us talking about them. Uh, we do
15:56
know there is antimatter.
15:58
Professor Fred Watson: There's just a hell of a lot.
16:00
Andrew Dunkley: Less of it than actual matter, if I recall
16:03
correctly. But if you've got, um, a molecule
16:05
of matter and a molecule of antimatter and
16:08
they collide, they just cease to exist.
16:11
Is that how it goes?
16:13
Professor Fred Watson: Yes, that's right, yeah. Um, what you get,
16:16
um, is so if you. The
16:18
difference between a normal matter
16:21
particle, like, uh, an electron,
16:24
and. And, uh, its antimatter equivalent
16:27
is the electrical charge is the opposite.
16:30
So the antimatter equivalent of an electron
16:32
is a positron. Um, it's got positive
16:35
electrical charge. Uh, and
16:39
when two
16:42
particles like that meet, they
16:44
annihilate. And what you get is a
16:47
gamma ray. You get a photon of gamma ray
16:49
energy which has a uh,
16:51
characteristic, a uh,
16:54
characteristic frequency, um
16:56
distribution. In gamma rays we call it
16:59
energy. Uh, in light we think of it as
17:01
wavelength, in radio waves we think it as
17:03
frequency. Uh, but it's the same thing
17:05
basically, uh, different, different levels of
17:08
energy. So you get these gamma rays which
17:11
will be emitted with a specific and
17:13
characteristic frequency and that's the way
17:16
that you might be able to detect
17:19
an antimatter star.
17:22
Andrew Dunkley: Um.
17:24
Professor Fred Watson: I think this story actually goes back, it
17:26
does go back to 2021. I've just found the
17:28
article that we referred to. Stars made of
17:30
antimatter might be lurking in the universe.
17:32
It's from Scientific American, a very
17:34
authoritative source. Um,
17:37
but what they were starting the story
17:40
with was something that happened in 2018
17:43
when uh, one of the
17:46
experiments on the outside of the
17:47
International Space Station which we talked
17:49
about in the last episode with great warmth
17:51
and admiration. Um,
17:54
it's one of those experiments may have
17:56
detected uh, two
18:00
basically uh, nuclei of anti helium. Um,
18:03
these are anti helium particles.
18:06
And so you mix that with normal helium
18:09
and you get the gamma rays.
18:11
Um, and so the question
18:14
is where, where does
18:17
that come from? And that was
18:20
the um, the outcome of this, the, the
18:22
suggestion that the easiest way to produce
18:25
anti helium is inside anti stars.
18:29
Um, which we don't, still
18:32
don't know whether they exist or not. Uh, but
18:34
really the, the point of Marx question is a
18:37
good one. Um, I don't think we know much more
18:39
about this uh,
18:42
since that you know that speculation.
18:46
Um, but what they're
18:48
suggesting, uh, I might actually read
18:51
uh, from that Scientific American article
18:54
and acknowledge the source there.
18:57
It was written by
18:59
Leto Supuna who's the author
19:02
of that. Um, and I think it
19:06
sort of puts it a lot better than I can.
19:09
Antistars would shine much as normal ones do,
19:12
producing light of the same wavelengths, but
19:14
they would exist in a matter dominated
19:16
universe. And so as particles and
19:19
gases made of regular matter fell into
19:22
an antistar's gravitational pull and made
19:24
contact with its antimatter, the resulting
19:27
annihilations would produce a flash of high
19:29
energy light. That's the gamma rays I
19:30
mentioned. We can see this light as a, There
19:33
you go. We can see this light as a specific
19:35
colour of gamma rays. Um, and
19:38
so one of the teams that they're Talking
19:40
about took 10 years of data, uh,
19:43
which amounted to roughly 6,000 light
19:45
emitting objects. They paired the list down
19:47
to sources that shone with the right gamma
19:49
ray frequency and that were not ascribed to
19:51
previously catalogued astronomical objects.
19:54
Um, so this left us with
19:57
14 candidates. This is one of the authors,
20:00
uh, talking, which in my opinion and my co
20:02
author's opinion, two are, uh, not antistars.
20:05
Um, yeah, but they say
20:08
if all those sources were such stars, that
20:11
means one anti star would exist for every
20:13
400,000 ordinary ones in our stellar neck of
20:15
the woods. So we're still
20:18
struggling to get our heads around this and
20:20
I'm not sure whether any more of uh,
20:23
these characteristic gamma ray flashes,
20:27
uh, have been observed or what the latest
20:30
is on this topic. But it is a very
20:32
interesting one, I think. Um, thank you,
20:34
Mark, for raising it again because it's one
20:35
we should perhaps look at in a bit more
20:37
detail. Might try and dig out some
20:40
stories for when I return to space nuts on
20:42
um, antistars and see what we've got
20:45
in that. Uh.
20:47
Andrew Dunkley: Do you think they could exist for him?
20:49
Professor Fred Watson: I do think they could exist, yeah. Um, I mean
20:52
it's one of the big puzzles of the universe
20:53
as to why there's so much matter and so
20:56
little antimatter. When our best theories of
20:59
the origin of the universe suggest that
21:01
antimatter and matter were created in equal,
21:04
you know, in equal proportions. So
21:07
uh, it's, it's one of these, it is, it's one
21:10
of these issues that um, is, keeps on
21:12
bubbling up and uh, you know, challenging
21:15
our understanding.
21:16
Andrew Dunkley: Yeah, uh, well, I'm probably dredging up
21:19
the same joke I used four and a half years
21:21
ago, but there's a lot of, there's a lot of
21:23
doesn't matter in astronomy as well.
21:27
Professor Fred Watson: See, I can hear Jordy. You got a lot of Jordy
21:30
there. Yeah.
21:32
Andrew Dunkley: Um, but yeah, antimatter stars are
21:35
right up there with white holes. Uh, we've
21:38
never seen one. But there's, you know,
21:41
there's certain elements of
21:43
science that think these things exist.
21:46
Um, but we've just never found the,
21:50
the direct evidence or proof, have we?
21:52
Professor Fred Watson: No, that's. Excuse me. That's correct.
21:54
Um, just along those lines, there's
21:58
something, um, that cropped, um, up about a
22:00
week ago or two weeks ago. Um, it's a
22:03
gravitational wave event which I think
22:06
dates back to 2019. And you know,
22:08
gravitational waves measured by LIGO and uh,
22:12
Kagra and Virgo, the three big gravitational
22:14
wave detectors in the world. They um,
22:18
uh, this particular, most Most gravitational
22:21
waves come from, uh, either neutron stars
22:23
colliding or neutron stars colliding with
22:24
black holes or black holes colliding. And
22:27
they always have characteristic signature.
22:28
They spiral together and then when they come
22:31
together at the end they produce this
22:32
characteristic chirp, um,
22:35
which is when they merge. Um,
22:38
and, uh, that usually lasts a few seconds
22:41
that, um, run up to the chirp. Uh, but
22:44
this one in 2019 only lasted, I think
22:47
it was a tenth of a second. Uh, and
22:51
one interpretation of that is that,
22:55
uh, it was two very massive
22:58
black holes. I think. I think that's the way
22:59
around. It goes. Could be the other way
23:01
around. Anyway, a,
23:04
um, recent paper from China, and I think this
23:06
was two weeks ago, proposed that you could
23:09
get nearly the same modelling, which,
23:12
because they model these gravitational wave
23:14
phenomena if, uh, it turned out
23:17
that what you were looking at was not
23:18
colliding black holes but a collapsing
23:21
wormhole. Um, and that's
23:24
the first evidence that I think anybody has
23:26
put forward for the existence of wormholes.
23:28
But it's still very conjectural because,
23:32
um, the likelihood, you know, the model of
23:34
just two black holes colliding actually fits
23:36
the data slightly better than the model of
23:39
the collapsing wormhole. But people are still
23:41
looking at these things as they are for white
23:43
holes and, um, I hope also for
23:45
antimotor stars.
23:47
Andrew Dunkley: Yes. Yeah. Well, um, I suppose
23:50
there's so much to consider in the
23:53
universe that some things just don't get the
23:56
amount of time and attention they probably
23:58
deserve. But the workforce
24:01
is spread so thin in astronomy and space
24:03
science, I would imagine so,
24:06
um. Yeah, it's hard to deal with everything.
24:09
Professor Fred Watson: With everything. That's right. There's
24:11
certainly enough questions to keep us busy
24:13
for a long time. The world of astronomy.
24:15
Absolutely.
24:16
Andrew Dunkley: Yeah. All right, Mark, thank you. Hope
24:19
all is well in Canada.
24:23
Roger, you're live right here.
24:24
Professor Fred Watson: Also, space nuts.
24:26
Andrew Dunkley: Our final question comes from Dave. And, uh,
24:29
Dave is from Inverel in Northern, uh, New
24:32
South Wales, Australia. As someone who is
24:34
lucky enough to enjoy fairly low light
24:37
pollution where I live, I like to
24:39
attempt some nighttime photography now and
24:42
then. Lately I've been using the nightcap
24:45
app on my phone. I've got that one as well.
24:47
Uh, with, uh, the meteor setting, he says
24:50
to try and capture some meteor photos.
24:53
Uh, I find the best time to see a great
24:55
falling star is just as I'm getting the phone
24:58
set up, ready to start shooting.
25:01
Just wondering if you have any advice for
25:04
when to try and capture a meteor on camera.
25:07
Example, uh, time of night, direction, et
25:09
cetera. Or should I just uh, wait until a
25:12
good meteor shower turns up. Uh, and how many
25:15
meteors would we expect to see collide in
25:18
our atmos, uh, collide with our atmosphere on
25:20
any given night. Um, also,
25:23
uh, great to hear you back Andrew and
25:25
hearing. Enjoy, uh, hearing your travels. Uh,
25:28
when you talk of Iceland, it makes me very
25:31
keen to return.
25:32
Can I ask which company you cruised with?
25:34
Dave from Inverel. Yes, you can.
25:38
Uh, the uh, the answer, uh, is Princess.
25:41
It was Princess Cruises. Uh, we made the
25:44
news early in the cruise when we got smashed
25:47
just um, southwest corner of Australia by
25:50
a squall that knocked the ship over, not
25:52
completely 7 degree list which
25:55
we took three hours to straighten up. I had
25:57
to go up to the bridge and help the captain
25:59
by, you know, using my weight to stand at
26:02
the. No, I didn't. Uh, but uh, it was um,
26:05
pretty hair, uh, raising for a while there.
26:07
We uh, made the news all over Australia
26:09
apparently. But um, yeah, it was the Princess
26:11
Cruise Line. Um, and we've been with them
26:14
many times on other cruises and they're uh.
26:16
I, I really enjoy them. Um, they
26:19
probably uh, it's debatable but I
26:21
think food wise they're probably the best.
26:24
But yes, um, now, and you
26:27
mentioned the. Sorry, go on. Br.
26:29
Professor Fred Watson: I was just going to say if you want to avoid
26:31
uh, the rigours of sea travel, you could come
26:33
with Dark Sky Traveller. We go up to Iceland
26:36
pretty regularly too. Yes, well, there's a
26:37
thought.
26:38
Andrew Dunkley: Yeah.
26:39
Professor Fred Watson: Yeah.
26:39
Andrew Dunkley: So the downside of cruising is it's slow.
26:42
Yeah, I mean it's very relaxing. But if you
26:44
do want to get somewhere in a hurry, it's
26:47
probably not the way to do it. Um,
26:50
and uh, Dave also mentioned the nightcap app.
26:53
Uh, I do have that one on my phone. I haven't
26:55
had an opportunity to really use it because
26:58
it's um, there's too much light around
27:01
here.
27:02
Professor Fred Watson: Uh, what does it do, Andrew? What's the,
27:04
what's the purpose of the nightcap?
27:06
Andrew Dunkley: I haven't got my phone with me but uh, you
27:09
can preset it to
27:11
photograph in low light
27:14
and, and you can either put it in manual
27:17
mode or you can have this series of presets
27:19
where you can, if you know what you want to
27:22
photograph, it will set up the phone
27:25
to create the exact situation you need to
27:27
take that particular photograph. Yeah, yeah,
27:29
it's really, it's really good software. Um,
27:32
but I haven't really had a chance to use
27:35
it properly. But it can do time lapse and all
27:38
sorts of things. It's really good gear.
27:41
Uh, so yeah, when and where
27:44
and how to take low light
27:47
photographs, Fred Watson, of meteors.
27:49
Professor Fred Watson: That was meteors crucial thing. Yeah. From
27:52
Dave's question. And yeah, so Dave up
27:55
in Verrel will have pretty easy
27:58
access to dark skies.
28:00
Andrew Dunkley: Uh, yeah, that's, you know why? You know why?
28:01
Because they're not putting the electricity
28:04
on up there for another 10 years.
28:06
Professor Fred Watson: Okay. Uh, sorry.
28:08
Andrew Dunkley: Everyone asks, in the 30
28:11
odd years I've lived here people have often
28:12
asked do you have electricity where you are?
28:15
Um, so I couldn't help that joke.
28:17
Professor Fred Watson: No. Well you do. We did in Kun Durban as well
28:20
but we were at the end of the line and uh, so
28:22
if ever there was a thunderstorm we usually
28:24
left our electricity, they were gone.
28:26
Andrew Dunkley: Ah yeah, we had that problem the first 15
28:28
years we lived here.
28:31
Professor Fred Watson: Um, but they do have electricity in Varel and
28:33
they also have dark skies. Relatively easily
28:35
accessible by just driving up a few
28:38
few kilometres further up the highway one way
28:41
or the other.
28:42
Um, so, so meteors. Um,
28:45
yeah. Dave's question, how many meteors are
28:46
coming in? Uh, quite a large number. We think
28:49
it's something like 100 tonnes, 50 to 100
28:52
tonnes a day meteoritic material hits the
28:55
atmosphere that's worldwide. Uh, but that
28:58
means there are billions of meteors streaking
29:00
through the atmosphere because most of them
29:01
are specks of dust. Um, and they
29:04
can, yeah, sporadic meteors as they're
29:07
called, they can whiz through the earth's
29:08
atmosphere at any time. People talking about
29:11
this stargazing I was doing at uh, Sea
29:13
Lake uh in rural Victoria last week, um,
29:17
quite a few people were spotting meteors as
29:19
they flashed through the sky. I was looking
29:21
at screens so I missed a, most of them. Um,
29:24
but uh, probably the
29:27
time to uh,
29:30
really concentrate on uh, if you serious and
29:33
I think you kind of need an all sky lens
29:35
effectively for good meteor photography. Um,
29:39
um, uh, the new generation of
29:42
phones do have very wide angle lenses
29:46
but they're not fisheye in the sense that you
29:48
can see the whole sky. Uh, but they're wide
29:50
enough probably to use the
29:53
snag with them is that they've got a low
29:56
uh, uh aperture. So a
29:59
high focal ratio, uh, you know
30:02
the ratio of the focal length to aperture and
30:05
what you need is a low focal ratio to give
30:07
you fast imaging, it's what we call a fast
30:09
lens. Whereas these wide angle ones tend not
30:12
to have that. Uh, and so you're tossing up
30:15
you know, the relative merits of a very
30:17
wide angle view or
30:20
likely to capture more meteors or a narrow
30:23
angle of view. But greater sensitivity, so
30:25
you'll see fainter meteors. So, um,
30:28
that's, you know, taking all that into
30:29
consideration. I, um, haven't tried meteor
30:32
photography with my phone. I've done a lot of
30:33
aurora borealis photography with it and that
30:36
works really well because they're sensitive.
30:38
But it will be an interesting thing to try.
30:40
Uh, it's the fact that you need the shutter
30:43
open for a long time. But I guess what you
30:45
can do is just keep on taking short
30:47
snapshots. Um, the point I was going to
30:50
get to is when you think about the Earth, uh,
30:54
in its orbit around the sun,
30:56
uh, the forward facing side of the orbit
30:59
is where you are after midnight.
31:02
So after midnight means that you're
31:05
on the leading edge of the Earth and that's
31:07
where you're going to get the most meteors.
31:09
Basically, uh, as the Earth, uh, ploughs
31:12
through the various clouds of dust, you've
31:14
got meteor showers which come from big clouds
31:17
of dust that the Earth goes through. But
31:19
these things are always best seen in the
31:22
early morning, um, when you're on the side
31:24
after midnight. So that's the best advice I
31:27
can give. I'd be interested to hear how you
31:28
get on Dave and, uh, what sort of results you
31:31
might get.
31:31
Andrew Dunkley: Yeah, yeah. And if you do get a couple of
31:34
good ones, send them in and we'll, we'll, um,
31:36
post them on our Facebook page or you can
31:38
post them yourself on the Facebook group,
31:39
whatever you like. Um, love to see what you
31:41
come up with. We do get, um, some great
31:44
astronauts of photography from space, uh,
31:47
arts listeners on the Facebook group
31:48
sometimes. So, yeah, um, more than happy to,
31:52
uh, have you, uh, post them
31:55
on that page, Dave, and
31:57
hopefully that will help. But, uh, yeah, uh,
31:59
the idea of having to get up and do it at the
32:01
middle of night, not, not appealing. But, uh,
32:03
that's life in astronomy, isn't it,
32:05
Fred Watson?
32:06
Professor Fred Watson: Tis a bit, yeah.
32:08
Andrew Dunkley: Yeah. All right, Dave, thanks very much for
32:11
your question. Don't forget, if you've got a
32:12
question, send it in to us because we'd love
32:14
to try, uh, and answer it. No guarantees, of
32:17
course, uh, but you go to our website,
32:19
spacenutspodcast.com spacenuts
32:22
IO Click on the AMA tab and you can send, uh,
32:26
uh, questions there, audio or text. Just
32:28
remember to tell us who you are and where
32:30
you're from and we'll do the rest. Or
32:33
Huw in the studio will, if he ever turns up
32:36
again. He didn't turn up today.
32:39
I don't know what he was doing. Probably
32:41
trying astrophotography in the middle of the
32:43
day. Just never listens to us.
32:46
That's his problem. Uh, Fred Watson, thank
32:49
you as always and, uh, bon voyage.
32:52
Have a safe journey. Uh, enjoy your time in,
32:54
in Japan and Ireland and the, uh, UK
32:58
and uh. Yeah, and, and look forward to
33:00
hearing about your travels when you get back.
33:02
And we will welcome, uh, Jonty Horner from
33:05
the University of Southern Queensland, uh,
33:08
with, um, Space Nuts for the
33:11
foreseeable future. So take care,
33:13
Fred Watson, and thank you.
33:15
Professor Fred Watson: Thank you, Andrew. Uh, I'll miss you all,
33:17
but, um, I'll be glad to come back and, uh,
33:19
talk to you sometime before Christmas.
33:21
Andrew Dunkley: Okay, catch you then, professor, uh,
33:23
Fred Watson Watson, astronomer at large, and
33:25
from me, Andrew Dunkley. Thanks again for
33:27
your company. We'll see you on the very next
33:29
episode of Space Nuts. Until then, bye
33:31
bye.
33:33
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