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Time Travel & Cosmic Questions: The Science Behind Our Universe · Space Nuts: Astronomy Insights & Cosmic Discoveries

0:00
Andrew Dunkley: Hello yet again, this is Space Nuts, a Q and
0:03
A edition. My name is Andrew Dunkley. Thanks
0:05
for joining us and hope you're well wherever
0:07
you are. Could be Yemen, could be the United
0:09
States, the uk, Australia, New Zealand,
0:11
India, Sweden. Uh, I've
0:14
probably missed a couple. Um, uh, one person
0:17
in each country listens to us. So that's yay,
0:20
our entire audience. Uh, on today's
0:22
episode, uh, Andy the train driver in UK has
0:25
got back to us. He's asking a question about
0:28
time travel. Uh, we've also got another
0:31
UK question about orbiting telescopes.
0:34
A, uh, question aimed at, uh, one of the
0:36
things that, uh, most people on Earth love,
0:38
and that is gold, the metal. Uh,
0:41
and we are, uh, getting a what if question
0:43
from Ryan about the sun straying through
0:46
a star forming nebula. What might happen?
0:49
We will tell you what might happen or what
0:52
might not happen. We might not answer any
0:54
questions at all on this episode of
0:57
space nuts. 15 seconds,
1:00
distances internal.
1:01
Professor Fred Watson: 10, 9. Ignition
1:04
sequence start. Uh, space nuts.
1:06
Andrew Dunkley: 5, 4, 3, 2.
1:07
Professor Fred Watson: 1.
1:07
Speaker C: 2, 3, 4, 5, 5, 4, 3, 2,
1:10
1.
1:11
Andrew Dunkley: Space nuts. Astronauts report. It feels
1:13
good. And to help us, uh,
1:16
figure all of that out is Professor
1:18
Fred Watson Watson, astronomena, ah,
1:21
at large. Hello, Fred Watson.
1:24
Professor Fred Watson: I've been described as an astronomist as
1:27
well.
1:27
Andrew Dunkley: Astronomist. I sounded like a Muppet
1:30
then.
1:32
Professor Fred Watson: Yes.
1:33
Andrew Dunkley: Never mind. How are you, Fred Watson?
1:35
Professor Fred Watson: Okay, thank you. Yes, that's good. Recovering
1:37
from my knee surgery. These things
1:40
take time, but, uh, it's going in the right
1:43
direction, which is great.
1:44
Andrew Dunkley: Indeed. Let's, um, let's
1:47
tackle some questions, shall we?
1:50
All right, here we go. Our first one comes
1:52
from Andy.
1:54
Andrew Dunkley: Hi, Andrew and Fred Watson. This is Andy, the
1:55
train driver from London. Uh, hope you're
1:58
both doing well. I hope you also received the
2:01
video I sent you. Um, just a short one, but,
2:03
uh, interesting.
2:07
Time travel and relativistic speeds.
2:11
Um, if I was to travel away from the earth
2:14
for, uh, 100 years at 99.9%
2:17
the speed of light and then turned around and
2:19
came back at the same speed, I would age
2:22
differently to someone that was being left
2:24
behind. Would that be classed as time
2:26
travel? And obviously we haven't got
2:29
the capability, uh, of moving that fast yet.
2:32
But if we did, could we use that to travel
2:34
through time? Thanks guys, Love the
2:37
podcast and see you on the next one.
2:40
Andrew Dunkley: Thanks, Andy. Uh, great to hear from you.
2:43
Yeah, we both got, uh, Andy's video
2:46
and uh, I think we both emailed him back
2:48
about it. But, uh, yeah, he took us for a
2:50
little walk up the railway tracks and showed
2:52
Us, um, the train he was driving
2:54
that day and what it was capable of and was
2:57
really fascinating. So um, yeah, thanks for
3:00
that Andy. It's um, it's nice to see how
3:02
other people work and live and um,
3:05
you know, train driving the different world.
3:07
To me, I've done it once. Um, and
3:10
uh, that was on an old diesel locomotive, um,
3:13
that we, that we went out on one Sunday. That
3:16
was a, it was a vintage um,
3:19
unit. And I got to spend the return trip
3:22
up the front because I was doing uh, doing
3:24
coverage for the ABC at the time. And uh, so
3:26
I uh, I got to do the story Honk the
3:29
Horn. Because in New South Wales,
3:33
nanny, um, state we call it, uh, they have to
3:36
blast the horn at every level crossing
3:39
and you don't know how many there are until
3:42
you have to actually blow the horn every
3:43
time. Uh, it's a safety protocol.
3:46
Um, thanks Andy. Uh, time travel,
3:48
Fred Watson. I love time travel stories or
3:51
questions.
3:53
Professor Fred Watson: Uh, yeah, this is um, the only way that we
3:55
can travel through time. What Andy has
3:59
suggested I used um, to have a
4:02
recipe which I think it meant Visit.
4:05
You go 100, 500 light years
4:10
to a star. You need to travel at 99 point. I
4:13
think it's 9,997% of the speed of
4:16
light for which we don't have the technology
4:18
yet. But if you did, uh, and then came
4:21
back, you would have aged 10 years
4:24
while the planet has aged 1,000
4:27
years. Because you've done two, 500 year
4:30
stints at nearly the speed of light. 500
4:32
light years stints at nearly the speed of
4:34
light. So um, it is a way of
4:37
travelling forward through time. Um,
4:40
as long as you can put up with being
4:43
pushed in a spacecraft that's going to go at
4:45
that sort of rate. And
4:48
that's courtesy of special
4:50
relativity, which is for objects that travel
4:54
near the speed of light. General relativity
4:56
has time dilation as well, uh, for
4:59
objects that um, uh,
5:01
near intense gravitational fields. And I
5:03
think we saw the science fiction version of
5:06
that in interstellar.
5:08
Andrew Dunkley: Yes we did.
5:09
Professor Fred Watson: Which certainly had its, its
5:11
weaknesses in terms of the scientific
5:13
arguments. Um, but, but relativistic
5:16
time travel by speed does work. Uh,
5:19
it's theoretically possible uh, for you to do
5:22
that so you're travelling forward in time.
5:23
What you can't do under really any
5:26
circumstances is go backwards in time. Um,
5:30
there have been people who've looked at the
5:31
prospect from the point of view of um, sort
5:34
of gravitational loops in space time.
5:37
Uh, but if you want to go back in time,
5:39
you've sort of Got to set things up first so
5:42
that the point you go back to, you've got to
5:45
do something, whether it's build a
5:47
gravitational detector or something, you have
5:50
to do something there. And that isn't really
5:53
backward time travel because you've got to
5:56
start with the time that you want to travel
5:58
back to. If I can put it that way.
5:59
Andrew Dunkley: Yeah. Um, and the other problem
6:02
is, uh, you've got to work out where the
6:04
Earth probably would have been at the
6:07
particular point where you want to go.
6:08
Otherwise you'll end up in, you know,
6:14
you'll be in a piece of space that hasn't got
6:16
a planet. Um, yeah,
6:19
there's all sorts of things you need to
6:20
consider.
6:22
Speaker C: Um,
6:24
Andrew Dunkley: I thought I came across an article recently,
6:27
um, that suggested they
6:30
now think backward time travel
6:33
may be plausible. But I can't remember where
6:35
I read it. It might have just been one of
6:37
those speculative articles. It was quite a
6:40
while back that I read it. Didn't see it in
6:43
the news, um, at
6:45
any sort of significant level. But um, yeah,
6:48
um, but yeah, it is possible. Not
6:51
possible, but it is certainly scientifically
6:54
plausible to go forward in time.
6:57
Uh, but you're not really going forward in
6:59
time because your time still remains
7:02
the same according to our clock. It's
7:05
just that because of the speed you're
7:07
travelling, you are not
7:10
ageing as fast as other people.
7:13
Professor Fred Watson: Correct. Uh, what you might call the outside
7:16
observer, you're still ageing at the normal
7:18
rate, but, uh, but you're not.
7:21
Andrew Dunkley: Yeah, you've just wasted a decade proving
7:24
a theory, more or less.
7:27
Professor Fred Watson: Although to go forward a thousand years in
7:29
time might be quite interesting.
7:32
Andrew Dunkley: I suppose. So if you, um. If, yeah, and
7:35
if they ever achieve warp
7:38
technology, um, you could go,
7:41
uh, you could go a hell of a long
7:44
way forward in time, couldn't you?
7:47
Professor Fred Watson: Well, um,
7:50
yeah, if you could warp space so that you
7:53
can, you know, drop through a wormhole or
7:56
something like that. That's a different
7:58
story.
7:59
Andrew Dunkley: Well, that removes the time paradox, doesn't
8:01
it?
8:02
Professor Fred Watson: Yeah. Basically you can take shortcuts
8:05
through space time.
8:06
Andrew Dunkley: That's right, yes, correct. Um, I think we
8:09
had a similar question last week, uh, in
8:12
regard to um, uh, the movie Hail
8:15
Mary project, uh, asking how could
8:18
uh, scientists do 11 light years in
8:22
um, you know, whatever speed he was doing and
8:25
uh, how long would it take him? How much
8:28
younger would he be when he came back, that
8:29
sort of thing. Uh, yeah. And it comes down to
8:32
that time dilation issue, doesn't it?
8:34
Professor Fred Watson: Exactly. That's right. Mhm.
8:37
Andrew Dunkley: All right. Have we answered Andy's question
8:39
because it's very confusing.
8:41
Professor Fred Watson: The answer is yes.
8:42
Andrew Dunkley: Yes, it is. There it is.
8:44
Professor Fred Watson: Yes, Andy, whack your train up to
8:46
99.999% of the speed of light.
8:50
What happens to your passengers?
8:51
Andrew Dunkley: Yeah, especially when you stop fast.
8:55
Yeah, the cabin will get crowded. Um, thanks,
8:57
Andy. Nice to hear from you.
9:02
Now we've got another question, Fred Watson.
9:04
Uh, which I have right in front of me
9:07
here. Hello, Professor Fred Watson and
9:10
Andrew. Thank you for answering my past
9:12
questions. It's always nice to get answers,
9:14
uh, to my incoherent questions this, uh,
9:17
time. My question is about orbiting
9:19
telescopes like Hubble, uh, not SK
9:22
Survey telescopes. Uh, are observations
9:25
planned to minimise the time that the Earth
9:28
is between the telescope and the target?
9:31
Uh, are multiple targets recorded
9:33
concurrently as the telescope whizzes around
9:35
Earth? Is satellite orbit,
9:39
uh, parallax a problem, an advantage, or,
9:42
um, uh, unusually irrelevant
9:45
because space is really, really big.
9:48
It's so big.
9:49
Andrew Dunkley: Yeah.
9:50
Andrew Dunkley: Anyway, uh, and I'm sorry it's three
9:52
questions, but at least they aren't about
9:55
black holes. Thanks for the sterling effort,
9:57
Nick from Cambridge. Uh,
9:59
so, yes, um, Hubble. Um,
10:03
yeah, our observations plan to
10:06
minimise the time that the Earth is between
10:08
the telescope and the target. That's an
10:09
interesting one because, yeah, it is an
10:11
orbiting, uh,
10:14
uh, telescope. Uh, whereas the others are out
10:16
in the L2 Lagrange point. So
10:19
they're not, as they don't have anything
10:21
blocking their view.
10:24
Professor Fred Watson: There are limitations, though, that amount to
10:26
the same thing with the. You can only point
10:29
it in certain directions. Uh, so it means
10:32
during the course of the year you can cover
10:33
the whole sky, but you can't just
10:36
point it randomly in any direction.
10:38
Andrew Dunkley: You got to time it right.
10:39
Professor Fred Watson: Yes, quite so, as with the Hubble as well,
10:42
because, um, what happens when
10:46
time is granted on a telescope like the
10:48
Hubble? Uh, and this is, you know, to the
10:51
applicants who successfully convinced the
10:54
gatekeepers that, uh, their project is worth,
10:57
uh, spending a few hours of Hubble time on.
10:59
Uh, when, when, when those
11:02
observations are brought together, they, they
11:04
fall into the hands of a scheduler. Uh, so
11:07
that they're scheduled for in exactly that
11:09
way. Um, so that they're going to be
11:12
visible when the telescope is
11:15
at that orientation with respect to the
11:17
Earth. Uh, in other words, keep the Earth out
11:20
of the way. So that's certainly the case.
11:22
It's not a random thing. Um, the
11:25
scheduling of space telescopes is very, uh,
11:28
complicated and quite carefully done.
11:31
That was the first question.
11:33
Andrew Dunkley: Are multiple targets recorded concurrently as
11:36
the telescope whizzes around Earth?
11:38
Professor Fred Watson: Um, um,
11:41
the Hubble looks at one thing at a time.
11:44
But yes, if you, if you,
11:48
depending on, you know, where the object
11:51
is in relation to the ah, Earth, you might do
11:54
sort of n seconds of integration on one
11:57
object. N seconds of integration on another.
11:59
And then on the next orbit, repeat that, uh,
12:02
something like that. So that you could. It's
12:04
not concurrently, but it's doing them, you
12:07
know, dovetailing them together so that you
12:09
get the best performance. And I forgot what
12:12
the last question was. I think we might have
12:13
answered it already.
12:15
Andrew Dunkley: Is satellite orbit parallax
12:17
a problem or an advantage or
12:20
irrelevant?
12:21
Professor Fred Watson: Irrelevant. Uh, for most of astronomy, if
12:24
you're looking at the moon, it's not, um, the
12:26
moon is near enough that the parallax
12:29
differences caused by, um, the spacecraft
12:32
being on one side of the Earth and then on
12:33
the other will be enough. But for pretty well
12:36
everything else, uh, you can ignore it.
12:38
Andrew Dunkley: Okay, interesting. Uh, and of course,
12:41
um, yeah, we're sending more and more of
12:44
these, um, things into space. And, um,
12:47
the, uh, Vera Rubin is. No,
12:50
no, it's the other one.
12:51
Professor Fred Watson: Um, uh, the one you're talking about. It's a
12:53
Nancy Grace Roman.
12:54
Andrew Dunkley: Nancy Grace Roman has just been, uh,
12:56
launched. So it's, it's heading out. Uh,
12:59
and, uh, I think what M is that about 100
13:01
days to get there? Something like that.
13:03
Professor Fred Watson: Yes, that's right.
13:05
Andrew Dunkley: So it'd be getting pretty close, wouldn't it?
13:07
Professor Fred Watson: Yes, I think it's. I'm, um, caught up with
13:10
where it is at the moment. But I think it's
13:11
in good shape and nearly at its, um,
13:14
vantage point.
13:16
Andrew Dunkley: I want to find out now.
13:18
Professor Fred Watson: Good. Well, tell me when you do.
13:21
Andrew Dunkley: Um, yeah, we'll have a look. Uh,
13:25
um, so it was launched on the 30th of
13:27
August. So, uh, it's probably coming
13:30
up on about a third of the way there.
13:32
Professor Fred Watson: Yeah, sounds about right.
13:33
Andrew Dunkley: Yeah. Okay. There you go. Thank you,
13:36
Nick. Uh, I hope we managed to adequately
13:39
answer your question. That's what we strive
13:40
for here on Space Nuts. A Q and A edition
13:43
with Andrew Dunkley and Professor Fred Watson
13:46
Watson.
13:49
Okay, Houston, we've had a problem here.
13:51
Speaker C: This is Houston.
13:51
Andrew Dunkley: Say again, please. Houston, we've had a
13:54
problem. We've had a main B plus undervolt.
13:56
Roger, main B interval. Okay, standby 13.
13:58
We're looking at it. Space butts. Of course,
14:01
if you're only. Yes, Earth, Yes.
14:03
If you're only half listening to that, um,
14:05
that radio call from Apollo 13 about what,
14:08
you know, about their main B bus undervolt
14:11
problem. You, you Would have thought they
14:13
were actually hit by a bus. So,
14:16
um, yeah, it can be very confusing. Um,
14:19
now.
14:20
Professor Fred Watson: Oh, gosh.
14:21
Andrew Dunkley: Uh, Fred Watson, let's, uh, go to our next
14:22
question. Uh, this comes from Ash in
14:25
Brisbane. Hi, Ash. Uh, I've got a spanner to
14:28
throw into the works. In a previous episode,
14:30
you mentioned that when neutro stars
14:32
collide, the gravity is so extreme that
14:35
essentially no debris escapes. Now
14:37
here's where my brain started making funny
14:40
noises. I'm a bit of a gold
14:43
fanatic, and I was under the impression that
14:46
regular supernovae aren't energetic enough
14:49
to make a heavy, uh, element like gold.
14:52
I thought the current thinking is that
14:54
neutron star mergers produced much of
14:57
the universe's gold. So here is my question.
14:59
If no debris escapes a neutron collision,
15:03
how did all the gold end up here,
15:05
quite literally, uh, for me to admire,
15:08
hoard, and dream about buying more of,
15:11
uh. Have I misunderstood what nothing escapes
15:14
means? Does some material actually get
15:16
flung out before the merged objects
15:19
settle down? Or have I completely missed a
15:22
piece of the puzzle? Love the show and thanks
15:24
for feeding my curiosity every week. Looking
15:27
forward to hearing your thoughts. Cheers. Uh,
15:29
Ash from Brisbane, that is a really good
15:31
question. Is there a fundamentally simple
15:34
answer?
15:35
Professor Fred Watson: Yeah, I think, um, stuff can escape from
15:38
a neutron star collision. Maybe I glossed
15:41
over something in the past. Um,
15:44
I mean, we know neutron star collisions
15:47
not only produce, um, a
15:50
significant amount of, uh, gravitational
15:54
waves, but we also get, um,
15:56
electromagnetic radiation from that as well.
15:59
So that's something else that can escape. Uh,
16:02
and there must be debris, uh,
16:04
because otherwise. Exactly. Uh, as Ash
16:07
says, uh, you wouldn't get the interstellar
16:10
medium being sort of seeded by, uh, by
16:13
gold.
16:16
Andrew Dunkley: It still makes you wonder like, you know, the
16:18
two neutron stars collide, cataclysmic
16:21
explosion, stuff gets flung. I mean, they're
16:23
not gold bars floating out in space, are
16:25
they? So what form does the
16:28
gold take?
16:29
Professor Fred Watson: It's, It'll be atomic, atomic gold.
16:32
Andrew Dunkley: Okay?
16:32
Professor Fred Watson: Basically atoms of gold that if you had
16:35
enough of them, they'd form a gas. Uh, but
16:39
you, um, know, they're. They're probably
16:42
quite rarefied. Um, it's.
16:44
It. The gold's an interesting one though,
16:47
because we think most of the gold on Earth
16:50
must have arrived after the Earth's
16:51
formation. Because if gold was a
16:54
significant proportion of the
16:57
gas and dust cloud that the Earth formed from
16:59
it, all the gold will be in the middle. It
17:02
will be mixed up with the iron core, uh,
17:05
because of its mass. So, um, the
17:08
thinking is that other objects, like
17:11
broken up protoplanets, which would Give rise
17:14
to meteorites, uh, and small asteroids.
17:17
Those things bombarding the earth are
17:19
probably where most of the Earth's gold came
17:21
from. But in turn they would have come from,
17:24
um, a neutron star collision.
17:26
Andrew Dunkley: Yeah.
17:27
Professor Fred Watson: They're called kilonovas now, are they,
17:29
uh, like a thousand kilo
17:32
nova? Ah. Rather than a supernova.
17:35
Andrew Dunkley: Wow. Does that make them bigger or just, you
17:37
know, nastier? Smaller. Oh, okay. Yeah,
17:40
yeah. Super, super bigger. Yeah. Right,
17:42
gotcha. Yeah. We're still waiting for the
17:45
next big one, aren't we?
17:47
Professor Fred Watson: Uh, yes, in terms of, uh, supernovae. That's
17:50
right. There's a couple of candidate stars
17:52
that might blow their top sometime within the
17:54
next few thousand years. Yeah.
17:57
Andrew Dunkley: Yeah, we'll have to hang around for that.
17:59
It's like m. Yeah. The difference is, um,
18:02
between that and waiting for a solar eclipse
18:04
is you can get a date for a solar eclipse.
18:06
You can't get a date for a supernova.
18:09
Professor Fred Watson: 22nd of July, 2028.
18:11
Andrew Dunkley: Yes, I know where I'll be. I
18:14
don't have to move for once.
18:16
Professor Fred Watson: No, you don't. You probably forget and have a
18:18
golf match because it's Saturday afternoon.
18:20
Andrew Dunkley: Well, it is a Saturday.
18:21
Professor Fred Watson: Yeah.
18:21
Andrew Dunkley: Ah, but I'm usually finished by then.
18:25
I can imagine there'll be people that will be
18:27
out there playing that are oblivious to it
18:29
and suddenly it'll pitch black.
18:31
Professor Fred Watson: We, we hope nobody will be oblivious to it.
18:34
That's one of the times that I'm
18:35
Andrew Dunkley: pretty sure the news will be significant.
18:37
It's already. There's a Facebook page that's
18:39
been dedicated to it already, so I've joined
18:42
that. And they're constantly. They're already
18:44
looking for accommodation. Fred Watson.
18:46
Professor Fred Watson: Yeah, there will be.
18:47
Andrew Dunkley: Yeah. But, um, yeah, Ash, um,
18:50
it's. The stuff does get away.
18:53
Um, and, and gold
18:56
does end up in space. Gets picked up by the.
18:58
Or distributed by the, um,
19:01
the debris, I suppose. And some of it ended
19:03
up on Earth. Uh, and I still, I
19:06
believe still the amount of pure gold
19:09
that's been, that's been found. And
19:12
um, and, and you know, what do
19:15
you call it? Um, refined on Earth still
19:18
would only fill. Is it one
19:21
or two Olympic size swimming pools.
19:24
That's the world's total amount of gold at
19:26
the moment. It's not much, is it?
19:29
Professor Fred Watson: Not really. No. No, you're right.
19:32
I don't think I've got any actually.
19:34
Andrew Dunkley: Um. Oh, I've got this.
19:37
Professor Fred Watson: All right. Okay, good. Very good.
19:38
Andrew Dunkley: That's my grandfather's wedding ring. Uh, my
19:41
grandmother gave it to me and said, when you
19:43
get married.
19:44
Professor Fred Watson: Oh, uh, that's lovely.
19:45
Andrew Dunkley: So that ring now has got
19:49
80, 40, 50,
19:51
57. Oh, hang on, 40. Nearly.
19:55
Yeah. 90. 90.
19:57
Andrew Dunkley: Nearly.
19:57
Andrew Dunkley: 93 years of marriage on it
20:01
without. With our, my grandparents.
20:04
Um, marriage and, and Judy and I are coming
20:06
up on 40 years. Can you believe that?
20:09
Professor Fred Watson: Um, no,
20:12
Andrew Dunkley: no.
20:12
Speaker C: January.
20:13
Professor Fred Watson: Think of you as a young couple.
20:15
Andrew Dunkley: January, 40 years, marriage. Yeah, it's
20:18
hard to get your head around, isn't it? What
20:20
have we done with our lives? Uh, anyway, hope
20:23
you're doing something good
20:24
Professor Fred Watson: for the anniversary, Andrew.
20:25
Andrew Dunkley: Uh, we're going to Antarctica.
20:28
Professor Fred Watson: Right.
20:29
Andrew Dunkley: We wanted to um, put our initials in the
20:31
snow,
20:33
Professor Fred Watson: um, as you do.
20:34
Andrew Dunkley: Yeah, we're not going ashore. We're not doing
20:36
that. We're doing the um,
20:39
environmentally friendly version of the
20:41
train.
20:42
Professor Fred Watson: Very good.
20:42
Andrew Dunkley: Yeah.
20:43
Professor Fred Watson: It's the right thing to do.
20:45
Andrew Dunkley: Indeed. Okay. Uh, thanks Ash. Uh, great to
20:48
hear from you. Keep collecting the gold and
20:50
if you've got any spare, you know where I
20:51
live. Uh, our final question, Fred Watson
20:54
comes from. Um,
20:57
I've got to find it. It's from Ryan.
20:59
Speaker C: Hey guys, it's Ryan from Hokassin.
21:02
Delaware. Yes, Delaware actually exists. I
21:05
have a question and if you would permit me, I
21:07
would be interested to hear answers, uh, from
21:10
both of you. I recognise
21:13
that our solar system and our sun is
21:16
rocketing through the universe. Rocketing
21:18
around the galaxy. Well, not rocketing, but
21:21
you know what I mean. Um, and that currently
21:24
our solar system is in what is known as the
21:27
local interstellar cloud. It's a
21:29
very thin diffuse patch of
21:32
gas that we're going through. And the sun's
21:35
heliosphere has enough outward pressure to
21:38
protect us from this interstellar medium.
21:41
My question is, what would happen
21:43
if our sun were to stray through a
21:46
dense star forming nebula? Something
21:49
that has much higher
21:52
parts, um, per million or even I don't know
21:55
what dense is defined as in a star forming
21:58
nebula. Um, but if our sun were to wander
22:01
through one of these things, what would
22:03
happen to the earth? What would happen to the
22:05
heliosphere? What would happen to our solar
22:08
system? And again, if you permit me, I'd be
22:10
curious to hear the sci fi writer writer on
22:13
your show answer first. Thanks so
22:16
much guys. Keep uh, up the great work.
22:18
Andrew Dunkley: Thank you, Ryan. Uh, I was thinking, um,
22:21
Martin Berman Govine could have tackled this
22:24
one. But um, he didn't pick up the phone when
22:26
I rang. Um, and that's who I
22:29
assume he wanted to hear from in terms of
22:30
science fiction writers. And um,
22:33
I. Look, I did
22:36
research this because from a science
22:38
fiction point of view I'd like to Think it
22:41
would, um, the sun, which means the Earth
22:44
and the rest of the solar system would go
22:45
with it. Uh, the sun would, uh, start to
22:48
fuel itself up on all that, um, meaty
22:51
goodness in a nebula. And we
22:54
suddenly realise that our life on Earth is
22:57
threatened. Significantly, the truth is much
22:59
more boring. I'll
23:02
let Fred Watson tell the truth, but, um, from
23:05
a science fiction perspective, look, it's got
23:07
merit. If you wanted to stretch,
23:11
um, the truth a very, very.
23:14
Not break the rubber band, but, um, you
23:16
probably would break the rubber band. But,
23:18
uh, I'd go down the line of,
23:21
um, yes, if it happened,
23:24
uh, the sun would, um, have a
23:27
feeding frenzy like a great white shark.
23:29
And, uh, Earth would suddenly
23:32
risk being gobbled up by what may become
23:35
a super sun as a consequence.
23:38
But, uh, I just don't believe that's.
23:41
That's possible. And, uh,
23:44
the chances of this happening, Ryan, are
23:47
pretty much nil because the
23:49
nearest nebula to Earth, the, uh,
23:52
Helix nebula, is about 650 light
23:55
years away. So, um,
23:58
um, that sort of
24:01
puts us out of the realm of possibility. But,
24:03
you know, you never know. There might be one
24:06
we've missed and is sneaking up on us as we
24:08
speak. Time, uh, for you to save this
24:11
question, Fred Watson.
24:12
Professor Fred Watson: I'm just cheating here because, um, you've
24:15
made me think of something I should know.
24:19
Uh, so what we're really talking about,
24:22
star forming regions are, uh, technically
24:25
known as giant molecular clouds. And,
24:27
um, the nearest one is 1500 light
24:30
years away.
24:31
Andrew Dunkley: Oh, there you go.
24:32
Professor Fred Watson: Uh, it's the Orion molecular cloud complex.
24:34
That makes sense because we know the Orion
24:37
Nebula is one of the brightest in the sky.
24:40
So giant molecular clouds are indeed where,
24:43
uh, star formation is taking taking place.
24:45
Um, and the densities there, because
24:48
it's a molecular cloud, uh, are higher
24:50
than what they would be in the sort of normal
24:53
interstellar medium. Um, but
24:56
it would be, um. The thing that
24:59
would probably make the biggest difference is
25:01
that as you approach this thing, and
25:04
two people I used to work with at the Royal
25:06
Observatory in Edinburgh, um, Victor Klub and
25:09
Bill Napier, both theorise
25:12
that this has happened in the past, that
25:14
a giant molecular cloud passing
25:18
close to the solar system would
25:20
disturb the Oort cloud to the extent
25:23
that you would bombard the inner solar system
25:26
with cometary objects. In other words, comet
25:29
nuclei coming from the Oort cloud, which we
25:31
think is the reservoir of these things at the
25:33
edge of the gas cloud that made our own
25:36
solar system. So there could be quite
25:39
catastrophic, uh, consequences. In
25:42
fact, uh, Victor and Bill wrote a book called
25:45
the Cosmic Serpent in Which they
25:48
equated, if I remember rightly, uh,
25:51
some of the um,
25:53
geological and
25:56
um, mythical, if I can put it that way,
26:00
uh, the stories of death and
26:02
devastation, um, of which there are
26:05
plenty in ancient records. Uh,
26:08
those, uh, and the geological
26:11
evidence of there having been um, debris
26:14
bombarding the earth, uh, they sort of
26:16
equated that with the passage of. Potential
26:19
passage of known molecular. Giant
26:22
molecular clouds. Now their work, that work
26:24
was done 70 years, sorry, 50 years ago
26:27
or thereabouts. A bit less than that, um,
26:30
40 years ago. 46 years ago to
26:33
be exact. Um, so things have probably
26:35
moved on in terms of what we know about these
26:38
things and also about the geological
26:41
record too and what the
26:43
anthropologists tell us about some of the
26:46
um, destruction, uh,
26:49
stories, uh, that pervade, uh, ancient
26:51
texts of whatever kind they are.
26:54
So uh, there might be more to say about that.
26:56
But it's still a real phenomenon, potentially
26:59
that you could get, um, catastrophic
27:02
bombardment of the inner solar system because
27:04
of the disturbance, the gravitational
27:05
disturbance of a big lump of stuff not very
27:08
far away.
27:09
Andrew Dunkley: Wow.
27:10
Professor Fred Watson: Yeah.
27:11
Andrew Dunkley: That's not boring at all.
27:12
Professor Fred Watson: No, I don't think it's boring. No, I think
27:14
it's.
27:15
Andrew Dunkley: Makes a science fiction potential story much
27:17
more exciting.
27:18
Professor Fred Watson: Yes, well, it does. You could mix the two
27:21
together and get a good answer. Probably.
27:23
Andrew Dunkley: Good.
27:24
Andrew Dunkley: Ryan will be relieved to know that
27:27
getting to the um, star forming field
27:30
that you uh, brought up, Fred Watson,
27:32
1500 light years ago away, will take us
27:35
at our current velocity 15 million years.
27:39
Professor Fred Watson: Yes, that's probably right. If we were
27:42
heading in the right direction.
27:43
Andrew Dunkley: If we were heading in the right direction,
27:45
that's the other point and we're not.
27:49
So I think we're pretty safe at the moment,
27:52
Ryan. But thanks, uh, for your thoughts and I
27:55
do love the what if questions. That one was
27:57
just a little bit out of my realm of
28:00
imagination. Um, um, but yeah,
28:03
um, but Fred Watson made us feel good by
28:05
saying it would be catastrophic.
28:06
Professor Fred Watson: Anyway, yes,
28:10
Andrew Dunkley: uh, thank you, Ryan. Thank you to everyone
28:12
who contributed. And if you've got questions
28:14
for us, please send them in to, uh, our
28:16
website or via our website, uh, Space Nuts
28:19
IO and just click on the AMA button at the
28:22
top and uh, you can send text or audio
28:24
questions. Don't forget to tell us who you
28:25
are and where you're from. We'd be, uh,
28:27
thrilled to hear from you. And if you've
28:28
never ever sent us a question before, please
28:30
do. Um, always looking for newbies.
28:34
Uh, we like our regulars too, of course. And
28:36
uh, please leave a review wherever you listen
28:38
to us or watch us if you watch us. That's.
28:40
I'm really sorry about that. But, um, anyway,
28:43
that's, you know, head for radio. I've had
28:46
it for a long time. I can't change it. Um,
28:49
thank you, Fred Watson. We'll see you real
28:50
soon.
28:51
Professor Fred Watson: I hope so. Yeah. Looking forward to it. Thank
28:53
you.
28:54
Andrew Dunkley: That's Professor Fred Watson Watson,
28:55
Astronomer at large. And thanks to Huw in the
28:58
studio who, um, also did some
29:01
straying today. Um, like the Earth, um,
29:04
or the sun straying through a nebula. He went
29:06
straying. So, uh, we haven't seen him for a
29:09
couple of months now. And from me, Andrew
29:11
Dunkley, thanks for your company. We'll catch
29:13
you on the next episode of Space Nuts. Bye.
29:15
Bye. You've been listening to
29:18
the Space Nuts podcast,
29:21
available at Apple Podcasts, Spotify,
29:24
iHeartRadio or your favourite, favourite
29:26
podcast player. You can also stream
29:28
ondemand@bytes.com.
29:30
Professor Fred Watson: this has been another quality podcast
29:32
production from Bytes.
29:34
Speaker C: Com.
29:34
Andrew Dunkley: Um,