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Angular Momentum, Cosmic Time Dilation & Dark Matter Mysteries Unraveled | Q&A · Space Nuts: Astronomy Insights & Cosmic Discoveries

0:00
Andrew Dunkley: Hi there. This is Space Nuts, A, uh, Q
0:02
and A edition. My name is Andrew Dunkley,
0:05
your host. Great to have your company. Hope
0:06
you're well. Coming up on this episode,
0:08
Fred Watson will be answering questions about
0:10
angular momentum. The age of the
0:13
universe versus the perception of time.
0:16
That's an interesting one. The vastness of
0:18
space and the big leap.
0:21
Stick around. We'll deal with all of that
0:23
coming up soon on this edition of space
0:26
nuts.
0:26
Mark Rabelais: 15 seconds. Guidance is internal.
0:29
Professor Fred Watson: 10, 9. Ignition
0:32
sequence. Star space nuts.
0:34
Andrew Dunkley: 5, 4, 3.
0:35
Professor Fred Watson: 2. 1.
0:36
Andrew Dunkley: 2, 3, 4, 5, 5, 4, 3, 2,
0:38
1. Space nuts.
0:40
Mark Rabelais: Astronauts report it feels good.
0:43
Andrew Dunkley: And we welcome him back once more. It's
0:45
Professor Fred Watson Watson, astronomer at
0:47
large. Hello, Fred Watson.
0:48
Professor Fred Watson: Hello, Andrew. How you doing? Seeing you
0:50
here.
0:51
Andrew Dunkley: Yeah. So unusual.
0:53
Professor Fred Watson: Doing all right?
0:53
Andrew Dunkley: Seems like ages since we last spoke.
0:56
Professor Fred Watson: Yes.
0:57
Andrew Dunkley: Could have been a few seconds, though. Who
0:58
knows? We will be talking about time shortly,
1:01
so maybe the answer is in there.
1:04
Um, let's get down to business.
1:06
Uh, this first, uh, question comes from
1:09
Mark. Now, uh, it's actually two
1:12
questions about angular momentum. But, uh,
1:14
Mark,
1:18
he's sort of weeding this one out a little
1:21
bit. Uh, so, um, let's find out what he
1:23
wants to know.
1:25
Mark Rabelais: Hello, fellas. My name is Mark
1:28
and I reside in Baton Rouge,
1:31
Louisiana. My question,
1:34
my first question has to do with
1:37
the two black holes that were
1:40
very rapidly orbiting each other
1:43
just before they merged. And each of
1:46
those black holes presumably had
1:49
its own angular momentum and
1:54
was spinning, in a
1:57
certain sense, either clockwise
1:59
or counterclockwise. And,
2:02
uh, my question is,
2:05
if these two black holes,
2:08
as unlikely as it might be,
2:11
happened to be spinning
2:15
with equal
2:18
rates but in opposite
2:20
directions in such a way that
2:23
the net angular
2:26
momentum of the combined system
2:30
would be zero. Then would
2:33
the final new black hole
2:36
created have an angular momentum of zero?
2:39
Not sure if I posed that correctly. But I'm
2:42
sure you get what I'm saying, what I'm
2:44
meaning here. Could the
2:46
resulting black hole have a net angular
2:49
momentum of zero? And if so,
2:52
would that result in any unusual
2:56
characteristics if a
2:59
black hole was not spinning?
3:03
Anyhow, that's my first question. My second
3:06
question has to do with the
3:08
universe writ large. Um,
3:11
wouldn't the universe have a
3:14
net angular momentum when the Big
3:17
Bang occurred? I presume.
3:20
Although I don't understand why there would
3:22
be a non zero
3:25
angular momentum of the entire universe.
3:29
If the Big Bang
3:32
was perfectly symmetric, the net
3:34
angular momentum should be zero, should
3:37
it not? And, uh,
3:40
of course the Big Bang
3:43
was not perfectly symmetric. And that is what
3:46
I understand is the reason
3:48
for the uh, clumping of matter
3:52
as shown in the WMAP image.
3:55
I guess I'm getting too
3:58
off, off the beaten path here. But anyhow,
4:01
uh, it has to. My question is,
4:04
does the universe
4:07
have a net angular momentum and
4:10
what's the implications of that either way,
4:12
whether it does or does not? Anyhow,
4:15
see that's why I stay awake at night.
4:18
Okay guys, love uh, your podcast. Uh,
4:22
take care.
4:23
Andrew Dunkley: Thank you Mark. Yeah, there's a lot packed
4:26
into those, um, those ideas from Mark
4:29
Fred Watson.
4:30
Double barrel Question. Um, we'll start off
4:32
with the two black holes merging with equal
4:35
rate in opposite directions.
4:39
Would uh, they
4:42
achieve uh, zero angular
4:44
momentum under those special circumstances?
4:49
Professor Fred Watson: Uh, and the answer is yes, yes they could.
4:51
Um, so there are two things at play here.
4:55
Uh, one is the individual spin of each
4:58
black hole. Uh, most black holes
5:01
are spinning, uh, and
5:04
so those two, um,
5:08
the angular momentum of those two of each
5:10
black hole when they collide,
5:13
uh, it could be that they'll cancel out if
5:15
they're rotating at the same rate in the
5:17
opposite direction. Now normally, um,
5:19
that's unlikely to happen because
5:23
uh, you know, it will be very, very
5:26
unusual to have two black
5:29
holes with exactly the same rotation rate but
5:32
one the negative of the other one rotating in
5:35
the opposite direction. But it could happen.
5:37
It could happen. But the bigger phenomenon
5:39
uh, is actually the
5:43
orbital angular momentum of the
5:46
two black holes as they spin together.
5:49
Uh, that's where most of the angular
5:51
momentum in a binary black hole, a
5:54
pair of black holes, that's where most of it
5:57
lies, um, when they collide.
6:01
What happens to that angular uh,
6:03
momentum? Well it is radiated away
6:06
in gravitational waves. And that's one of
6:09
the things that is taken into account when
6:11
people look at a gravitational wave signal
6:14
coming from two colliding black holes.
6:16
Um, the angular
6:19
momentum gives rise to the um,
6:23
change in angular momentum is one of the
6:25
things that gives rise to the, to the uh,
6:28
gravitational waves that are observed. And
6:30
that's all modelled and all makes complete
6:32
sense. Uh, so um, in particular
6:35
though, um, that means that that's the
6:37
biggest component of spin. The
6:40
individual spin of each black holes is a
6:43
smaller one. Uh, but still,
6:46
um, it basically is uh, exactly
6:49
as Mark has postulated. Uh, they
6:52
could cancel out completely what happens to
6:55
the angular momentum. Once again it, it is
6:58
radiated out in the form of gravitational
7:01
waves. That's where the angular momentum
7:03
goes. It's a form of energy and that comes
7:05
out as energy that we can now measure with
7:07
our ah, gravitational wave detectors.
7:09
And turning to part two, which I
7:12
Andrew Dunkley: think, yes, the universe
7:15
um, yeah. Ah, assuming that
7:18
it radiated, radiated out in all directions
7:21
simultaneously in a spherical
7:23
way, um, would it have and
7:27
should it not have m net 0 angular momentum?
7:31
Professor Fred Watson: And apparently it does, uh, in the
7:34
sense that, uh, it has never.
7:37
There's no evidence for a
7:40
rotation of the universe as a whole.
7:42
Um, Mark, again is on absolutely the right
7:45
track because, uh, if there was
7:48
a rotation in the universe, you'd
7:50
expect to see particular
7:53
patterns within the cosmic microwave
7:56
background radiation, which is what he
7:58
mentioned in relation to wmap, the Wilkinson
8:01
Microwave Wave Anisotropy Probe.
8:03
And, uh, we don't see that. We don't see, um,
8:07
characteristics that would suggest that the
8:09
universe is rotating. So it looks as though
8:12
there was enough symmetry in the Big Bang
8:15
itself, uh, that no rotation
8:18
was imparted to the universe. One of the
8:20
other issues with this, of course, is
8:23
if it was rotating, then you
8:26
have to, um,
8:29
basically invoke a central point,
8:32
uh, and an absolute reference frame. And
8:35
neither of these things are permitted in our,
8:38
uh, normal cosmological theories. Uh,
8:41
so it's just as well that it's not there.
8:44
And it's the fact that we don't see any
8:46
rotation that allows us to ignore the
8:48
idea of an absolute reference frame. Uh, we
8:51
just take the universe as a whole.
8:53
Andrew Dunkley: It's like a snow globe. Like the snow
8:56
globe's got no angular momentum, but
8:58
everything inside's doing all sorts of busy
9:00
stuff.
9:01
Professor Fred Watson: Uh, yes, that's right. That's a very nice way
9:04
to put it. Um, you'll go far, Andrew, with
9:07
analogues like that.
9:08
Andrew Dunkley: I went to a tourist shop to figure that out.
9:10
Yeah,
9:13
Professor Fred Watson: you've got to choose the right snow globe.
9:16
That's right.
9:17
Andrew Dunkley: Did you know that people who invented snow
9:19
globes never, ever, to this day, it's still
9:22
a trade secret revealed what the glittery
9:24
stuff inside a snow globe is.
9:27
Professor Fred Watson: No, I didn't know. That's true.
9:29
Andrew Dunkley: Look m it up. The
9:32
original inventors and the family that
9:34
started it still has control
9:37
of, um, uh, the invention to this
9:40
day have never ever
9:42
revealed what is inside a snow
9:45
globe. What makes all the glittery
9:48
snow like effect. They've never
9:50
told anybody. Uh, I think it's the same
9:53
stuff they put on KFC nuggets. But
9:56
I, uh, could be wrong. I could be
9:59
wrong. Secret herbs and spices,
10:01
maybe. Uh, thank you, Mark. A very thoughtful
10:04
question. Uh, and it sounds like, um, you're
10:07
on the money so you can actually go to sleep
10:09
tonight. Uh, well done.
10:12
Uh, our next question, Fred Watson, comes
10:14
from John. Does the age of the universe
10:16
depend on the gravity well, that you
10:19
exist within. If Andrew was living on a
10:22
planet orbiting a super massive black hole,
10:24
eg. Sagittarius, a star, uh,
10:27
time would be slower for him relative to
10:30
Fred Watson living on Earth. Would Andrew
10:32
then calculate the age of the universe, the
10:34
universe to be less than what Fred Watson
10:36
does? That one comes from John. That's a good
10:39
one. That's a what if question.
10:43
Professor Fred Watson: It is. We should try it out
10:46
one day. Yeah, uh, you can be the one
10:49
going and living on the black hole.
10:50
Andrew Dunkley: Yeah, uh, that I don't think it'd be a very
10:53
long lived situation. But uh, you know,
10:56
yeah, I'm happy to, happy to give it a
10:58
whirl.
11:00
Professor Fred Watson: So um, turning to the um,
11:03
um, the answer to John's uh,
11:05
conundrum. Uh, the, the answer is yes, there
11:08
is gravitational time dilation.
11:11
So if you were, you know, if
11:14
you were hanging around a black hole, you'd
11:17
think the universe would have a
11:20
younger age than an
11:22
observer in deep empty space.
11:25
But uh,
11:28
it is a small effect
11:31
compared with the size of the universe
11:34
at uh, large. So what we do is
11:37
we treat the age of the universe as a,
11:40
basically as a
11:43
universal constant. And you can sort
11:46
of imagine um, when we look at
11:48
for example the cosmic microwave background
11:50
radiation, we look around the whole sky
11:53
and we see the flash of the Big
11:56
Bang and we assume that it's the same age in
11:59
all directions. Uh, and
12:02
that's basically what we do.
12:04
We take, we take uh, the
12:08
flash of the Big Bang as being our uh,
12:10
yardstick for the 13.8 billion
12:12
years age of the universe. And
12:15
that's so it irons out, if I can put it that
12:18
way. This is the global view that irons out
12:21
all the local funny uh, gravitational
12:23
effects like you hanging around a black hole
12:25
and seeing a younger universe. This is
12:29
um, what you might call um, a
12:31
measurement made in a, in a, in a
12:34
preferred reference frame. You're just
12:36
talking about reference frames in terms of a
12:38
rotating universe. This is the same issue.
12:41
This is the, the sort of standard reference
12:43
frame of the universe kind of defined by the
12:45
cosmic microwave background radiation. Um,
12:48
and so gravitational effects on that whole
12:52
picture are ah, minimal compared with what
12:54
might be felt when you were very close to
12:57
something with a very high gravity.
13:00
Andrew Dunkley: Okay, all right. I, I was surprised that
13:03
it went the way you said because I was,
13:06
I thought you were going to say no. For me,
13:08
time will pass as it would anywhere else.
13:10
It's just, you know, to the observer it would
13:13
be different. You wouldn't be moving.
13:16
Um, but, no but
13:19
from the inside it would
13:22
Be different because what you're looking at
13:24
on the outside would
13:27
age, uh, slower, therefore seem younger. Is
13:30
that what you said?
13:31
Professor Fred Watson: Yes, that's right. So, so the, um.
13:35
It is, it's, you know, you're, you're
13:37
observing from a different reference frame
13:39
when you're hanging around the black hole.
13:42
Uh, and that's. And so that it's. I mean, we
13:45
normally think, you know, we talk about
13:46
people falling into a black hole and they.
13:49
Time stops on the event horizon
13:52
as they cross the event horizon.
13:54
Uh, but that's how we normally think about
13:57
these things. But if you, if you, if you
14:00
yourself are in the black hole, then it looks
14:03
as though the whole universe is doing
14:04
different things like becoming younger
14:07
and things of that sort.
14:08
Andrew Dunkley: Extraordinary.
14:09
Professor Fred Watson: Yeah.
14:10
Andrew Dunkley: It's just such a weird place, isn't
14:11
Professor Fred Watson: it, when you're very weird. Yes.
14:15
Andrew Dunkley: All right, John, Uh, great question. And, uh,
14:17
yeah, the answer was yes. This is Space Nuts
14:20
with Andrew Dunkley and Professor Fred Watson
14:22
Watson. A Q and A edition.
14:29
Mark Rabelais: Space Nuts.
14:30
Andrew Dunkley: Okay, Fred Watson, our, uh, next storey
14:33
comes from Pete, who says hi.
14:36
Great show. Well done. Oh, thank you.
14:39
Um, in trying to understand the impact of
14:41
dark matter matter on the stability of the
14:44
galaxy, I was perplexed by the lack of
14:46
reported impact on our solar system. And
14:49
then closer to home, the Earth, the moon and
14:51
space traffic, uh, that
14:54
led me to a, uh, realisation that whilst we
14:57
see visual images of galaxies that look full,
15:00
that in reality, if all the
15:03
baryonic matter in the galaxy was accumulated
15:05
together, it would represent a minuscule
15:08
percentage of the volume of the galaxy. That
15:10
the galaxy may have 100 billion stars
15:13
but is basically empty. Dark
15:16
matter, whatever it turns out to be, is
15:18
likewise so sparsely distributed that
15:21
it is undetectable at the solar system
15:24
level. Maybe the professor, uh, could expand
15:27
on these comments for the benefit of all of
15:29
us who struggle to grasp the vastness of
15:32
empty space that constitutes the galaxy and
15:34
ultimately the universe. Many thanks from
15:37
Pete. What do you reckon, Fred Watson?
15:40
Professor Fred Watson: Well, Pete's right as well. Uh, we've done
15:43
really well today. We've had three
15:45
speculations, all of which have turned out to
15:47
be on the money. Um, it's the fact that,
15:50
um, dark matter, whilst we know it,
15:53
clumps. It clumps on
15:55
scales that are much bigger than the galaxy.
15:58
So our galaxy is in a blob of dark
16:01
matter that, um, actually, uh, is
16:05
much, uh, you know, much bigger
16:08
than the galaxy itself. So what that means
16:10
is that, um, exactly
16:13
as Pete says, you've got a uni,
16:17
to all intents and purposes, within the solar
16:19
system. And actually within the
16:21
galaxy itself too, you've got the kind of
16:24
uniform background of dark matter whose
16:27
gravitational influence, uh, is
16:30
there, but is kind of acts
16:33
equally in all directions to stuff that's
16:36
immersed in it, if I can put it that way. So,
16:39
yes, the solar
16:42
system is full of dark matter, um, but it's
16:45
effectively uniform. It's just like a
16:47
background uniformity, which is why
16:52
when we calculate the orbits of planets and
16:53
things like that, we can completely ignore it
16:56
because it's essentially a flat
16:59
space of, uh, of uniform
17:02
gravitational influence, if I can put it that
17:05
way. I don't think I'm explaining that very
17:06
well, but that's the bottom line. And it's
17:08
basically. It's exactly what Pete said.
17:12
Andrew Dunkley: And what did he say?
17:15
Professor Fred Watson: He said what I've just said,
17:19
that the, the blob of dark matter that the
17:21
galaxy's in is effectively uniform on
17:24
distances, uh, comparable with the, the
17:27
solar system and in fact on distances
17:29
comparable with the stars in the galaxy as
17:31
well.
17:31
Andrew Dunkley: Yeah, it's seems to be a need of
17:34
dark matter to have stuff
17:37
to hang around.
17:39
Professor Fred Watson: Yes. With. We think it's the other way
17:41
around. We think that the stuff gravitated
17:43
inwards, being pulled because of the
17:46
glut. The dark matter. That's right. And
17:48
that's what caused galaxies to form.
17:51
Uh, sort of built on a scaffolding of dark
17:54
matter, which was what was created in the big
17:56
bone.
17:57
Andrew Dunkley: Right. Wow. Okay. That
18:00
just makes it even more mysterious
18:02
really, doesn't it?
18:06
Professor Fred Watson: Um, well, it neatly explains
18:09
why galaxies are there because that, you
18:12
know, it's very convenient. It is convenient
18:14
to have galaxies. Yeah. That the,
18:17
this sort of web like structure, uh,
18:20
which we think dark matter,
18:22
um, you know, that was the shape of dark
18:25
matter. It was like a honeycomb of material,
18:28
except it's not material as we know it.
18:30
Um, that web like structure is actually
18:33
a direct consequence of the Big bang. It's
18:35
what we expect. It's what we expect the big
18:38
bang to do. Um, and, uh,
18:40
Jordi agrees with that.
18:42
Andrew Dunkley: Yes, he does have noticed.
18:43
Professor Fred Watson: Yeah, he's upset because.
18:46
Andrew Dunkley: Yeah, he, he's, he's dealing with a dark
18:48
matter by the sound of it. Poor old
18:51
Jordy.
18:52
Professor Fred Watson: Jordy. It's all right. It's okay.
18:54
Andrew Dunkley: It's okay.
18:55
Professor Fred Watson: Yeah, his tail's gone up again. It was very
18:57
down the second ago. Yeah.
18:59
Andrew Dunkley: We were talking about dark matter and
19:01
Professor Fred Watson: that's, that's what he is.
19:03
Andrew Dunkley: Yes.
19:03
Professor Fred Watson: Very dark indeed. Probably the blackest thing
19:06
in the whole house. Yes.
19:09
Andrew Dunkley: Um, I, I know there's. We get so
19:12
many Questions about dark matter and, and
19:14
dark energy and black holes. It's, um,
19:18
probably the top three things that people ask
19:21
us about. And, and
19:24
Jordy. We ask about Georgie all the time.
19:25
Sarah. Um, but, yeah, you know,
19:30
just never ceases to amaze me
19:33
that there are, like,
19:36
how long ago didn't we even know about dark
19:39
matter? And now we've started thinking, well,
19:41
okay, it's, it's doing a lot more than we
19:43
ever anticipated. And now we seem to have a
19:46
total reliance on it to keep everything
19:48
together. It's the, it's the glue of the
19:49
universe.
19:51
Professor Fred Watson: Um, it's a good way to put it.
19:53
Andrew Dunkley: Yeah, yeah.
19:56
Professor Fred Watson: What? Write a book. Should be on
19:59
radio.
19:59
Andrew Dunkley: All right, yes,
20:03
maybe one day. Uh, but, um. You think they'll
20:06
ever crack it? I've probably asked that
20:07
question many times, but, um, you know,
20:10
do you think they'll ever figure out what
20:12
this is and how it all came to be?
20:15
Professor Fred Watson: Yeah, I think so.
20:17
And, you know, there's, there's ideas buzzing
20:19
around all the time. We talked not very long
20:20
ago about the idea that suddenly people are
20:23
suspecting that, um, primordial
20:26
black holes might be a reality. And, uh, they
20:29
can come in any size you like, rather than
20:31
have to be bigger than the size of the sun.
20:34
Uh, and so one that's smaller than the sun
20:36
has been found. Uh, and that suggests that
20:39
primordial black holes may exist. And that
20:41
might open the whole debate again about
20:43
whether, uh, dark matter is made of
20:46
machos or wimps, uh, with the machos
20:49
being massive compact halo objects. That's
20:52
things like black holes. And the wimps are
20:54
weakly interacting massive particles, which
20:56
is kind of the preferred view now.
20:59
And then on top of that, there's the
21:01
possibility that we've got it all wrong
21:03
anyway, uh, that it might be
21:05
actually modified Newtonian dynamics that
21:08
work. So it's
21:11
still some open questions with regard to dark
21:14
matter. And we've been thinking about this
21:15
seriously, uh, for almost
21:18
the last 50 years. It was 1978 when Vera
21:21
Rubin's observations really hit home,
21:24
that there was something very basic about the
21:26
universe that we didn't understand.
21:29
Andrew Dunkley: Like how wasn't it throwing itself to pieces?
21:31
Professor Fred Watson: Yes, that's right.
21:32
Andrew Dunkley: That was the question.
21:34
Professor Fred Watson: That question was asked by Ken Freeman, who's
21:36
an Australian astronomer. He, he, uh,
21:38
published a paper in 1970 which was
21:41
saying galaxies are rotating too fast to stay
21:43
together. Yeah, um,
21:46
Vera postulated that there are halos of stuff
21:49
that keep them together. And that's when the
21:51
whole dark matter, um, vogue, if I can
21:53
put it that way, started yeah, and it's, it's
21:56
Andrew Dunkley: still the big question, isn't it? Uh,
21:59
one of several, but, yeah, one of the biggest
22:01
ones. Uh, thank you, Pete. Great question,
22:04
and, uh, thanks for sending it in.
22:09
Okay, we've had a problem here.
22:11
Professor Fred Watson: This is Houston.
22:11
Andrew Dunkley: Say again, please.
22:16
Okay, standby 13. We're looking at it.
22:18
Spacebuds, our final question
22:21
comes from, uh, uh, you were saying,
22:23
Fred Watson, that we. We've been right on the
22:24
money. These questions have been, you know,
22:27
spot on until now.
22:30
Berman Gorvine: Hello, space nuts. Uh,
22:34
Martin Berman Gorvine here, writer
22:37
extraordinaire in many
22:39
genres, here to accept
22:43
Professor Watson's thanks
22:46
for the Bee Gees
22:49
quip. And I'm asking
22:52
today about another
22:55
BG brother. This
22:57
one, uh, may not even exist,
23:01
and I know that, nonetheless, you
23:04
have gotten questions about him before.
23:07
And that would be Peel, Give.
23:11
Yes, Peel, Give,
23:14
otherwise known as
23:17
the Big Leap.
23:20
Can you somehow
23:24
circumvent
23:27
the absolute speed
23:30
limit of
23:33
the speed of light in the
23:36
universe by having
23:39
a, ah, quick, uh, dodge out
23:42
into another universe where the speed
23:45
speed of light is arbitrarily high,
23:48
which is a staple of
23:51
science fiction? Um,
23:54
is this theoretically possible?
23:57
Um, and even if it were,
24:00
would it be possible to go have
24:03
a visit with Mr. Peel Gibb
24:06
without being spaghettified
24:09
and turned into, um,
24:12
mush of particles without even
24:15
marinara thought?
24:17
Can't wait for the answer.
24:20
Berman Gourvine, over
24:23
and out.
24:26
Andrew Dunkley: Uh, thank you, Martin. I think he just
24:28
brought our, um, podcast episode back
24:31
to kind of the average
24:34
sphere in terms of. No, no,
24:37
I'm kidding. Um, love you, Martin. Love
24:39
you very much. Um, Peel Gibb. Peel
24:42
Gibb. The, um, the Big leap. So
24:45
I think I'm just trying to. I'm scratching my
24:48
head here. I, I think he's asking, is
24:51
the absolute speed limit of light
24:53
constant? If you could go and
24:56
visit another. Another universe in
24:59
comparison. Is that what he meant?
25:01
Professor Fred Watson: That's the bottom line of this question.
25:03
Yeah.
25:04
Andrew Dunkley: One answer for this, and it could be one or
25:06
the other.
25:07
Professor Fred Watson: Well, it is. It's, It's. No,
25:10
but, um, you know, just thinking aloud on
25:13
that. So, uh,
25:15
first of all, it is possible that in, if
25:18
there were other universes, some of the
25:20
fundamental physical constants might be
25:22
different. The charge on the electron might
25:24
be different, the speed of light might be
25:26
different. Um, that's
25:29
something we, we know so little about other
25:31
universes, mainly because we don't know
25:33
whether they exist, and there isn't really
25:34
any theoretical framework that says they do.
25:37
Uh, they have been suggested by some very
25:39
eminent people, but we really don't have any
25:42
more than suggestions. People have looked for
25:44
evidence for other universes in the cosmic
25:47
microwave background radiation that we're
25:48
talking about a few minutes ago. Um, but
25:51
unless you have an eye of faith, which one or
25:54
two people do, there's not really anything
25:56
there, nothing to see there. So um,
25:59
other universes may well not exist and even
26:01
if they do they might end up having the same
26:04
speed of light. We simply do not know. But I
26:06
think the main problem is going to be getting
26:10
from ours into another one. Uh because the
26:13
word universe means everything we can see and
26:15
observe or deal with. Uh,
26:18
and you know, um, transferring
26:21
from this universe into another one I
26:23
suspect is one that would, with
26:26
even with the most open minded science
26:28
fiction uh, brain in the world,
26:32
um, might cause problems. Uh, unless
26:35
you're Martin. Martin will cheerfully write
26:37
about it and um, I hope it's a bestseller.
26:40
Andrew Dunkley: I don't doubt it.
26:42
Professor Fred Watson: Um, I've read a bit of uh,
26:43
Andrew Dunkley: Martin's work and I've thoroughly enjoyed it.
26:46
So uh, yeah, I would encourage to
26:49
look up his books. Um, there's a few
26:51
goodies there. Um, yeah.
26:55
The speed of light intrigues me because
26:58
we know what it is, we know how fast it is,
27:01
what 300,000 kilometres per second or,
27:03
or whatever. Um, and
27:07
we can't even think about
27:10
going near that speed. I mean we can't even
27:12
achieve what, 2% of the um,
27:16
relativistic speed.
27:18
Uh, and if we could that'd be a major
27:20
achievement. But um, it's,
27:23
it's, it's an uh,
27:25
unfathomable number in the scheme of
27:28
things.
27:28
Professor Fred Watson: Fred Watson. It is. Um, and you
27:31
know the very good reasons for believing that
27:34
nothing can go faster than that. And that's
27:36
because as you accelerate things,
27:39
any object with mass, as you accelerate it,
27:42
uh, uh, the more
27:45
energy it takes. So uh, you know, every
27:48
metre per second per second that you add
27:51
to its velocity, um, you
27:54
kind of have huge energy penalties and
27:57
eventually in order it all sort of um,
28:00
basically asymptotes to infinity.
28:03
In other words you'd have to put infinite
28:05
energy into something, uh, to accelerate
28:08
something to the speed of light. And we
28:09
haven't got infinite energy so we're never
28:11
going to do it. Um, there'd be other problems
28:14
as well. Uh, so it is a real speed limit.
28:17
Uh, it's very sad from the point of view
28:20
of science fiction writers or from
28:23
scientists. Uh, you've got to find a way of
28:25
getting around it. I'm think you're a dab
28:27
hand at that. So um, but that's What?
28:29
Andrew Dunkley: I can't reveal anything. I'm just in the last
28:32
couple of chapters of my trilogy and I'm not.
28:34
No, I'm not going to blow the whistle on
28:36
myself.
28:36
Professor Fred Watson: No, no, don't do that. Don't do that.
28:38
Andrew Dunkley: But, yeah, short answer is yes, I've solved
28:41
that.
28:42
Professor Fred Watson: Yeah, good.
28:43
All right, well, I'm glad you have. Um, let
28:45
us know what you did to overcome this, uh,
28:48
infinite energy requirement.
28:51
Andrew Dunkley: Yeah, yeah. Uh, there are ways,
28:54
um, in theory,
28:55
Professor Fred Watson: but, yes, we haven't figured them out yet.
28:58
Andrew Dunkley: Um, so did we answer the question? Oh, yeah,
29:00
it was no.
29:01
Professor Fred Watson: Yes, it's no.
29:02
Andrew Dunkley: Yes, it's no, Martin.
29:04
Professor Fred Watson: No, but I do like the
29:07
idea. I do like the idea of the Peel Gibb.
29:09
The Peel Gib. Yes, yes, that's good.
29:11
Andrew Dunkley: Very interesting, Martin.
29:14
Uh, if you've got questions for us, please go
29:16
to our website and send them in
29:18
spacenatspodcast.com SpaceNats
29:21
are our two URLs. Uh,
29:23
we're working on a third URL. It's
29:26
peelgib.com. no, probably, um,
29:30
not. But, uh, yeah, you can click on the AMA
29:32
tab to send us questions. Don't forget to
29:34
tell us who you are or where you're from. You
29:36
can do that in, uh, audio or text
29:38
format and have a look around while you're
29:40
there. Don't forget, too, if you will, to
29:43
leave reviews, uh, on whatever
29:45
podcasting platform you listen to us through
29:48
or via or on.
29:50
Um, reviews are very, very helpful,
29:52
apparently. They, um, they tell people things
29:55
about us that we might not want them to know.
29:58
But anyway, uh, you, if you would do
30:01
us that, ah, kindness, we would be most
30:03
appreciative. Uh, and we are just about. We
30:06
are done, Fred Watson. Thank you very much.
30:07
And you're off for a few weeks because, um,
30:10
you've got, you've got some travelling to do
30:12
and some people to see and some bills to pay
30:14
and, and all that kind of stuff.
30:17
Professor Fred Watson: Yes, it's the travel that's taking me away.
30:20
Uh, but I'm, um, delighted that you will be
30:22
able to keep the flag, uh, waving and keep
30:25
the show on the road with our good friend
30:27
John T. Horner.
30:28
Andrew Dunkley: Yes, John T. Will be joining us from the
30:30
University of Southern Queensland, uh, for a
30:32
few weeks. Um, Fred Watson, thank you so
30:34
much. Uh, happy trails. Um, and, uh, to you
30:37
and Marnie. Have a good trip and we'll see
30:38
you when you get back.
30:40
Professor Fred Watson: Sounds great. Many thanks, Andrew, and talk
30:42
to you soon indeed.
30:43
Andrew Dunkley: Professor, uh, Fred Watson Watson, astronomer
30:45
at large, part of the team here at Space
30:48
Nuts, and thanks to Huw in the studio,
30:51
uh, who couldn't be with us today. He tried
30:53
to peel a gib and nearly cut his finger off.
30:55
And from me, Andrew Dunkley, thanks to your
30:58
company, we'll see you on the next episode of
30:59
Space Nuts. Bye. Bye.
31:02
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