Latest / Space Nuts: Astronomy Insights & Cosmic Discoveries / Black Hole Temperatures, Cosmic Mapping & the Mystery of Dark Matter| Q&A

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Black Hole Temperatures, Cosmic Mapping & the Mystery of Dark Matter| Q&A · Space Nuts: Astronomy Insights & Cosmic Discoveries

0:00
Andrew Dunkley: Hi there. Thanks for joining us again. This
0:02
is a Q and A, uh, edition of Space
0:05
Nuts, where we, uh, take audience questions
0:07
and we pretend that we know what we're
0:10
talking about in attempting to answer them.
0:13
Or we get it right sometimes, too. Uh,
0:15
today we're going to be answering a
0:18
question about, uh, the temperature of black
0:20
holes. I'm not sure we've been
0:23
there before. It may have come up, but, um, I
0:26
can't remember when. Uh, and a question,
0:28
uh, asking with the James Webb Space Text
0:31
Telescope and the Vera Rubin Telescope, how
0:34
much of the universe has been mapped?
0:36
I can tell you this much.
0:39
Uh, and the emptiness of space is being
0:42
questioned. And what difference will it
0:45
make to humanity, uh, if we
0:47
find dark matter and dark energy?
0:51
That's, um, a really interesting question.
0:53
And Fred knows the answer. We'll ask him
0:55
shortly on this edition of SpaceNuts.
0:57
Voice Over Guy: 15 seconds. Guidance is internal.
1:00
10, 9. Ignition.
1:03
Sequence time. Um, space nuts. 5, 4, 3,
1:06
2. 1. 2, 3, 4, 5, 5, 4,
1:09
3, 2, 1. Space nuts.
1:11
Astronauts report. It feels good.
1:14
Professor Fred Watson: And he's back.
1:15
Andrew Dunkley: And he has all the answers to all the
1:17
questions of life, the universe, and
1:19
everything. Professor Fred Watson, astronomer
1:21
at large. Hello, Fred.
1:23
Professor Fred Watson: No pressure there, Andrew.
1:25
Andrew Dunkley: None at all. None at all.
1:27
Professor Fred Watson: That's right.
1:28
Andrew Dunkley: Uh, let's get straight into it, shall we?
1:30
Um, uh, one of our regular contributors
1:33
is Casey, who has a very interesting
1:36
question about a subject we never discuss,
1:38
black holes.
1:40
Professor Fred Watson: Hi, guys, this is Casey from Colorado, and I
1:43
was thinking about the temperature of black
1:44
holes. I know that the accretion disk would
1:47
be very hot, but I was wondering, once you
1:50
get past the event horizon, if it would
1:52
be hot or, uh, cold. Why do we think this.
1:56
Thanks for the podcast, and I hope you're
1:58
both well. Thanks.
2:00
Andrew Dunkley: Thank you, Casey. She's got me thinking about
2:01
the temperature in Colorado because, like,
2:04
we're facing some horrific temperatures
2:06
around here at the moment, but I'd imagine
2:08
it'd be quite the opposite in Colorado this
2:10
time of the year.
2:13
Professor Fred Watson: Yeah, I think that's. That's absolutely
2:15
right, yes. Chilly part of the world in
2:17
winter.
2:19
Andrew Dunkley: Absolutely. Um, now,
2:21
temperature of black holes. This, this
2:24
one's interesting because I suppose it varies
2:26
on several factors. Um,
2:28
where you are, what you're doing.
2:32
I don't know what I would
2:35
like. It's not like the temperature of the
2:37
sun, is it?
2:39
Professor Fred Watson: No, it's not. Um,
2:43
I'm so glad Casey asked this
2:45
question because it sent me down a rabbit
2:47
hole that I haven't been down before. Oh,
2:49
wow. And it leads you straight to quantum
2:52
theory. Uh, uh, and
2:55
um, it's, you know, it's a
2:58
really, uh, in a sense it's quite
3:01
unexpected, uh, what's
3:03
happening. Uh, so
3:06
the bottom line is, whilst
3:09
as Cayce, exactly as Cayce says, the
3:12
accretion disk of the black hole is extremely
3:14
hot, uh, and you know, we're talking millions
3:17
of degrees there because that's where you get
3:20
X ray radiation from. It's the stuff
3:23
charging around the accretion disk, uh,
3:24
that's uh, swirl whirling around the black
3:27
hole itself. But the black hole
3:30
itself is the
3:33
opposite. It's really, really cold.
3:37
Um, and basically, uh,
3:40
it's because the
3:42
amount of radiation,
3:46
uh, that they release is
3:50
at a level, uh, which means its
3:53
temperature is measured in
3:55
gazillionths of a degree. It's
3:58
virtually absolute zero. Um,
4:02
they, they
4:04
basically, they're, it says,
4:07
quite a nice way of putting it, um,
4:10
which, which I've summarized, uh,
4:13
uh, I think this comes from Wikipedia.
4:16
It may come from AI actually. Uh, but the
4:19
bottom line is even though black holes pull
4:21
in matter and energy, their temperature is
4:24
incredibly low because their large mass
4:28
makes their event horizons
4:30
effectively cold thermal emitters
4:33
absorbing energy faster than they radiate it
4:36
at these scales. So that's the key to
4:39
what's happening that like everything
4:42
else, black holes sucks stuff. It sucks stuff
4:45
in, uh, and that stuff
4:48
is matter, which is equivalent to energy.
4:51
Uh, and because it's stuff that's going in
4:53
and not radiating outwards, uh,
4:56
even though there is what we call Hawking
4:58
radiation, which I'll get to in a second. But
5:01
that, um, uh, you know,
5:04
what it means is that the fact that there's
5:06
an energy input into the black hole,
5:09
it means that to the outside observer they
5:12
look cold. They look very, very cold.
5:16
There is a relationship, as you said, uh,
5:19
it might vary with some things. And what it
5:22
varies with, uh, is actually the mass of the
5:25
black hole. Uh, it's
5:27
roughly, uh, an inverse
5:29
proportionality proportionality. The
5:32
temperature is inversely proportional
5:35
to the mass. Um, and what that
5:38
means is for supermassive black holes, they
5:40
are extremely cold. And
5:43
that sort of figures because they're sucking
5:45
in more energy. And so the surface to an
5:48
outside observer would look colder. Uh,
5:50
they're talking about 10 to the minus 14
5:53
degrees kelvin. Um,
5:55
something with the mass of the sun,
5:58
um, is a
6:01
balmy 10 to the minus 7 degrees
6:03
Kelvin. It's still virtually zero,
6:06
but it's more, uh, more than the
6:09
supermassive black holes. So something the
6:11
mass of the sun, so it's inversely
6:13
proportional to the mass, uh, that inverse
6:16
relationship. Uh, and
6:19
so that's kind of what.
6:23
It's the Hawking radiation that
6:25
gives the black hole
6:29
a temperature. Essentially it's because
6:32
it's emitting radiation. Um, and
6:35
we've talked about Hawking radiation before.
6:37
Even though everything gets sucked into a
6:39
black hole, there's this quantum situation
6:41
where you can get, um, two
6:44
virtual particles being created from nothing
6:46
in empty space. One gets trapped by the black
6:49
hole, the other doesn't. And so we see that
6:51
as Hawking radiation, uh,
6:53
suggested by Stephen hawking in the 1970s.
6:56
Now very well established. But
6:58
yeah, to summarize, the bottom line is
7:00
Cayce's, uh, question is a good one. Uh,
7:03
because it turns out that black holes are
7:05
very, very cold indeed, despite the intense
7:08
heat of the accretion disk. Work that one
7:11
out. It's a really hard thing to put your
7:13
imagination around.
7:14
Andrew Dunkley: I suppose you compare it to the heat on the.
7:18
It's got nothing to do with it at all. But,
7:19
uh, by example, the heat on the, uh, sunward
7:22
side of Mercury versus the cool on the
7:25
shadow side. They're so extreme.
7:28
Professor Fred Watson: Um. Yes. Yeah, that's right.
7:30
Andrew Dunkley: The reason for the m. Same reason.
7:34
Professor Fred Watson: Well, it's similar because the dark side of
7:36
Mercury is cold, uh, because it's
7:39
radiating energy into space.
7:42
Um, uh, whereas, uh.
7:45
And that. That energy loss reduces the
7:48
temperature. Whereas with a black hole, it's
7:49
the other way around. The thing is, the thing
7:51
is sucking energy in at a greater rate than
7:54
it's emitting energy. Uh,
7:57
so Mercury would. Mercury's dark side would
8:00
lose heat by infrared radiation. Um,
8:03
that radiation, in the case of a black hole
8:05
is, Is much smaller than the radiation that
8:08
it's sucking in, which is why it looks
8:09
extremely cold. So I'm trying to. I'm
8:12
trying. Sense of the parallel that you drew.
8:14
And I think it's. I think it holds water,
8:16
Andrew. I think. I think it's a good, good
8:18
answer. Actually.
8:19
Andrew Dunkley: The water probably evaporate or freeze. But
8:21
anyway, freezing.
8:25
I just thought of a question. Um, so if a
8:27
black hole sort of,
8:30
you know, runs out of food, would that
8:33
cause an alteration in its temperature?
8:38
Professor Fred Watson: Um, I don't think so, because I think
8:40
once the. I get what you're saying,
8:43
and certainly in the argument that we've just
8:46
been talking about, you'd think that if
8:49
it's not sucking in energy anymore, uh,
8:52
or sucking in matter anymore, uh, it
8:55
would actually, uh, change its temperature.
8:58
Um, the reason why I think that might not
9:00
happen is because the only thing that,
9:03
uh, the temperature seems to be related to is
9:06
the Mass itself. So, um, there must be
9:09
a mechanism, and I'm sorry, it's eluding me
9:11
at the moment, uh, but there must be a
9:14
mechanism that sort of locks. Once you've,
9:16
once you've got a black hole of
9:18
sufficient mass, um, then, uh,
9:21
its temperature is sort of locked in.
9:24
Uh, it must still be taking in
9:27
energy in the form of radiation. So perhaps
9:30
that's what's happening. You know,
9:32
light certainly gets sucked into a black
9:34
hole, even if it's not got an
9:37
accretion disk of stuff to feed on.
9:40
Uh, the light's certainly going in and
9:42
perhaps that's uh, enough to keep the
9:44
temperature as low as we've described.
9:47
Andrew Dunkley: Indeed.
9:48
Professor Fred Watson: All right, thanks.
9:49
Andrew Dunkley: Uh, Casey, lovely to hear from you. Hope
9:50
you're coping with the, uh, minus 10 to the
9:53
15 degrees kelvin in Colorado.
9:56
Uh, our next question comes from
9:59
Eli.
9:59
Hello spacefarers. I'm writing from the
10:02
Coachella Valley Desert here in Southern
10:05
California. Uh, I've often thought, thought
10:08
some of the Google Earth like software would
10:10
be amazing to take into other galaxies
10:13
throughout the universe. Intriguingly, I
10:16
imagine you could take them back in time
10:18
according to estimates of cosmic inflation,
10:20
etc, all the way to the Big Bang in theory.
10:24
Um, to his question with James Webb and the
10:26
Vera Rubin coming online. How much of the
10:30
visible universe have we basically
10:32
mapped and how much are we projected to map
10:36
in say, the next decade? I think we've
10:39
actually talked about how much that they're
10:41
going to look at and how long it's going to
10:44
take. And I think Eli's going to be quite
10:46
surprised by the answer.
10:50
Professor Fred Watson: Uh, well, yes, that's right. I mean the key
10:53
words here are, uh, the Vera Rubin
10:55
Observatory, uh, because that will
10:58
map the entire sky down
11:01
to quite a significant depth. Not as
11:04
deep as the web will. Um,
11:08
although it is an eight meter telescope, the
11:10
web is only six and a half meters, so it's
11:12
probably not far short of it. Uh, the web, of
11:15
course, looking in infrared and the Vera
11:17
Rubin Telescope looking invisible light. But
11:20
it's going to photograph the whole sky,
11:23
Southern sky, uh, in,
11:26
uh, every three, three nights or so.
11:29
So that will build up over the years a
11:32
map of the things that don't change. I mean,
11:34
what it's looking for is things that do
11:35
change. But, um, as you
11:38
integrate for all that time, and by that I
11:41
mean you, you know, expose the detector to
11:43
the sky so that you build up the image, uh,
11:46
and you can add all those images together,
11:48
we'll have, we'll have a, almost a
11:51
complete map of the universe in the
11:54
Southern hemisphere. Because, uh, all the
11:56
visible galaxies will show up.
11:58
Andrew Dunkley: Uh.
12:01
Professor Fred Watson: We won't see the first galaxies. I don't
12:03
think it's going to be powerful enough to see
12:06
those. Uh, and we're not sure even that
12:09
the Webb has seen the first galaxies. Uh,
12:12
it's certainly seen some galaxies that we
12:13
think are uh, very early in the history of
12:15
the universe. And I think the Vera C.
12:18
Rubin Observatory will do the same thing.
12:20
Uh, but, um, you know, so we're not in
12:23
any sense getting a complete sense
12:26
of the consensus, sorry, a
12:29
complete census of the universe. Uh,
12:32
but it's not going to be far off.
12:35
Uh, and that's quite astonishing when you
12:37
think of where we were, you know, well, just
12:40
a few years ago. Certainly when I was a young
12:42
working astronomer in the 1970s, I would have
12:46
had somebody, it would have blown my mind to
12:48
think that we could map all the galaxies
12:51
uh, in one hemisphere of the
12:54
universe. Yeah.
12:56
Andrew Dunkley: Uh, what about the Northern Hemisphere? Is
12:58
there any work?
13:00
Professor Fred Watson: There's no equivalent. Uh,
13:03
the, the, there is. Uh, I mean the Nancy
13:06
Roman Space Telescope will look,
13:09
it's also a wide angle telescope like the
13:11
Vera Rubin Observatory instrument is.
13:15
But um, it's not as big.
13:18
Um, it is a 2.3 meter telescope.
13:21
It's basically a Hubble telescope but with a
13:24
wide field of view. Uh, so we'll
13:27
certainly see uh, pretty deep into the
13:29
Northern Hemisphere. Whether it will go as
13:31
deep as the Rubin Observatory, it's a
13:33
different matter. I don't think it will
13:34
because it's a much smaller telescope, but it
13:36
is in space and that gives it, excuse me,
13:39
that gives it advantages. There's no
13:41
atmosphere to, to get in the way. So
13:43
that's perhaps the best bet. Um,
13:47
the, excuse me, the other
13:51
big uh, instruments. I mean there's a number
13:52
of things going on. Um,
13:55
in terms of the two Keck telescopes which are
13:58
in the Northern hemisphere In Hawaii, they're
14:00
8 meter class telescopes, but they're not
14:02
wide angle. These are telescopes that are
14:04
built to uh, home in, in detail on um,
14:07
individual objects rather than to do wide
14:10
angle surveys. You need a specially designed
14:13
telescope for that. And Rubin is exactly
14:15
that. Um, there
14:18
isn't really an equivalent. Uh,
14:21
there is a wide angle telescope in La
14:23
Palma which is um, basically the same
14:26
as our UK Schmidt telescope here in
14:28
Australia. It's called the Ocean Schmidt
14:30
telescope. It's much older than our Schmidt.
14:32
In fact our Schmidt was modeled on it. And
14:34
that's a wide angle telescope that's
14:35
surveying the sky, but that's looking for
14:38
things like near Earth asteroids and things
14:39
of that sort, rather than penetrating deep
14:42
into the universe because it's only got a 1.2
14:44
meter aperture diameter, much, uh,
14:47
smaller than the 8 meters that the Rubin
14:49
telescope will have.
14:51
Andrew Dunkley: Yeah. Still,
14:53
um, what we'll know in 10 years time
14:56
will be extraordinary, uh,
14:59
through these two telescopes alone. James
15:01
Webb and Vera Rubin. Um, yeah,
15:04
who knows what they're going to un. Unveil.
15:07
Uh, and what, what about, you
15:10
know, Vera Rubin's first photograph was a
15:12
revelation. Uh, and what James
15:15
Webb is, um, is shelling
15:18
out is, is extraordinary. It,
15:21
it's, it's like, um, I don't know, Taylor
15:24
Swift. It's a hit record. Every time that,
15:26
every time they release a picture that's,
15:29
uh, it's incredible. So, Eli, the next
15:32
decade will be extraordinary. Um, so
15:34
just, you know, keep an eye on it would be
15:37
my advice. And thanks for the question. This
15:40
is Space Nuts with Andrew Dunkley
15:43
and Professor Fred Watson.
15:47
Three, two, one.
15:50
Space Nuts. I think we have
15:53
an audio question now. This one comes from
15:55
one of our regulars as well.
15:57
Professor Fred Watson: Hello, uh, Fred, Andrew, Jonti and Heidi,
16:00
this is Robert from the Netherlands.
16:03
I have a question for you guys about the
16:06
emptiness of space. Now,
16:09
every is always saying that space
16:12
is totally empty, right? One proton per
16:14
square meter, something like that.
16:18
However, not that long ago,
16:20
scientists did discover the Higgs boson
16:23
particle, the God particle, if you will.
16:28
So apparently everything is on this
16:31
grid of Higgs bosons, but
16:35
I'm not exactly an expert here. I'm just
16:37
curious if you guys could shed some lights on
16:39
this concept for me. So is it
16:42
just an enormous field of these very
16:45
regular Higbotons everywhere, and that's what
16:47
space is, or are they more numerous or
16:50
less dense in certain parts? Is
16:53
the void between galaxies actually a void,
16:57
or is it an empty field of God
16:59
particles? I really hope you can
17:02
shed some light. Thank you guys so much for
17:05
answering.
17:06
Andrew Dunkley: Thank you, Robert. Good to hear from you. Uh,
17:09
the emptiness of space.
17:12
So he said one proton per square meter.
17:15
Is that a, um, reasonable?
17:18
Professor Fred Watson: Uh, yeah, it's per cubic meter, something
17:21
like that. Um, yeah. Um,
17:25
uh, it's of that order, I think, in
17:28
intergalactic space. Um,
17:31
uh, but, uh, Robert's
17:34
right in the sense that
17:37
the Higgs field,
17:40
which is the other way of looking at
17:43
the Higgs boson, uh,
17:46
permeates, basically permeates
17:48
empty space. Um,
17:52
so, uh, this is
17:54
all about the duality of particles,
17:58
uh, with waves and with
18:01
what we call fields. Um, and we, I
18:04
mean, we imagine fields when we think of
18:06
gravitation because we think of a
18:09
Gravitational field as a. As a,
18:12
um. Um, sort of a.
18:15
Well, if I can put it that way, in a. In a
18:17
trampoline. Uh, the trampoline is the field.
18:20
You put something in it and it distorts it.
18:23
Uh, so with the Higgs,
18:26
uh, boson, the Higgs field, uh, is
18:29
this sort of invisible. It's been
18:32
described as a. Something like molasses or
18:34
syrup, uh, that
18:37
what, actually give particles their mass
18:40
because, um, they move slowly through it
18:42
because they get sticky. Uh, that's one way
18:45
of looking at it. Um, but, uh, the Higgs
18:48
boson is essentially, ah, um,
18:51
in a sense, a, uh, ripple in
18:54
the Higgs field. The Higgs field fills
18:57
space, and the Higgs bosons, uh,
19:00
are ripples in it. That's one way to look
19:03
at it. Um, it's.
19:06
It's, um. The. The.
19:09
The. I think what Robert's interested in is
19:12
the density of these
19:14
bosons, uh, whether
19:17
they are uniformly, uh,
19:19
distributed through space or whether
19:22
we're talking about, um,
19:25
you know, uh, bosons, uh,
19:28
that are, uh,
19:32
more dense in some places than others.
19:35
Uh, and I guess the.
19:38
The bottom line is that you would expect
19:40
there to be more bosons where there is
19:43
more, uh, more,
19:46
uh, what you might call normal matter, the.
19:48
The quarks and normal particles. Uh, but
19:51
that might not be the case. Uh, I need to
19:53
look at that a little bit more carefully,
19:55
Andrew, as you can probably tell, uh, to find
19:58
out what the distribution of Higgs bosons,
20:00
uh, are. If you assume the field is uniform
20:03
throughout space, which I think it might be.
20:06
Andrew Dunkley: Yeah, I suppose so. I mean, it's a
20:08
complicated area. You're talking about
20:09
particle physics, aren't you?
20:11
Professor Fred Watson: Really?
20:11
Andrew Dunkley: It's, um. Not.
20:13
Professor Fred Watson: I believe so, yes.
20:15
Andrew Dunkley: It's not basic maths, so,
20:17
um.
20:18
Professor Fred Watson: Yeah, it's particle physics we're talking
20:19
about. And, um, as I've said before, the
20:22
disclaimer is I'm not a particle physicist.
20:24
I've been to. Been to CERN a
20:27
few times and had my mind blown by what they
20:30
do there at the Large Hadron Collider. Uh, in
20:32
fact, I've been underground in the Large
20:34
Hadron Collider. Collider, but I'm still not
20:36
a physicist. A particle physicist. I,
20:38
uh, learn what the. They tell me
20:41
and kind of hope for the best.
20:43
Andrew Dunkley: Yeah. Aren't they making a larger hadron
20:45
collider?
20:48
Professor Fred Watson: They are planning, ah, one,
20:51
um, something called.
20:55
I can't remember. It's something like the
20:57
large, you know, the future Large Collider, I
21:00
think something like that, uh, which wears
21:02
the large Hadron Collider has a diameter or a
21:05
circumference of 27 kilometers. This is
21:08
100 kilometers. Um, if they
21:11
ever get the money for it, they are planning
21:13
an opening ceremony for it in
21:15
2017.
21:18
Andrew Dunkley: It's called the, uh, Future Circular
21:20
Collider.
21:21
Professor Fred Watson: Future Circular Collider. That's it.
21:22
Andrew Dunkley: Um, 91 centimeter ring, successor to the
21:25
Large Hadron Collider. And
21:28
they expect it to be Approved
21:33
in the 2728 financial year, by the look
21:36
of it. Construction starting in the 2000 and
21:37
30s.
21:38
Professor Fred Watson: So it's a little way off completion
21:40
in 2070.
21:42
Andrew Dunkley: 2070.
21:44
Professor Fred Watson: Yep. That's way. Well,
21:47
the last. Let's not hold out bread is what I
21:50
saw. Yeah. So I don't think,
21:52
um, you know, even with the best will in the
21:55
world, space nuts will probably have
21:57
dwindled to an audience measured in single
22:00
digits by then, so.
22:01
Andrew Dunkley: Possibly, possibly m. So. Yes,
22:04
well, we could pick up new listeners along
22:06
the way, but we won't know about it.
22:08
But, um, I suppose the other side to this
22:10
question, though, is that we do see
22:12
concentrations of
22:15
particles in some parts of the universe. Uh,
22:18
like dark matter seems to concentrate around
22:21
galaxies kind of thing.
22:23
Professor Fred Watson: Is that. Yeah.
22:24
Andrew Dunkley: That a different kettle of fish?
22:27
Professor Fred Watson: I think so. Because we're talking about
22:29
something that is, um, a property of the
22:32
universe itself, almost, um,
22:37
so that the Higgs field is everywhere.
22:41
Andrew Dunkley: Okay, gotcha. I understand. No, I get it. I
22:44
get it. Yeah.
22:44
Professor Fred Watson: All right. Yeah.
22:46
Andrew Dunkley: So, Robert, the answer is maybe, um,
22:49
possibly could be we, uh, need to do a bit
22:51
more homework. By the sound of it, we might
22:54
be able to get back to you on that.
22:57
Just Fred's writing a note so he doesn't
22:59
forget. Except you'll forget where the note
23:01
is.
23:01
Professor Fred Watson: Shh. All right. It's
23:04
in this book.
23:06
Andrew Dunkley: Thanks, Robert.
23:10
Okay, we checked all four systems,
23:12
space nets. And our final question
23:15
comes from Rennie. Um,
23:19
this is a really interesting question because
23:20
he says, I'm going to play devil's advocate
23:23
with this question. How will finding
23:26
out what dark matter and dark energy really
23:29
are, uh, help the Earth and all,
23:32
uh, of its life now and in the future?
23:35
Rennie from California. We've had a few US
23:38
Questions this week. That's nice. Two from
23:40
Kelly. Uh, so, yeah, what difference will it
23:43
make if we find this stuff to Earth and
23:45
life as it is now and in the future?
23:51
Professor Fred Watson: Um, so, um, yeah, if we magically
23:54
did find the answer to these things, and
23:57
we will eventually, uh, over a
24:00
period of time, I hope it's not. I Hope it's
24:03
before 2070, because I want to know, um,
24:07
what it will do will be complete our
24:09
understanding of the universe in a way
24:12
that is not the case at the moment.
24:16
So, um, it
24:18
basically refines our, uh, understanding,
24:22
uh, if I can put it this way, in a way
24:25
that's similar to the way
24:28
general relativity refined
24:31
it back in 1915.
24:35
Um, so the fact that we
24:38
suddenly understood gravity, the way
24:40
gravity works in a new light,
24:43
which is what general relativity did,
24:46
um, meant that, uh,
24:50
yes, the physicists could go away
24:52
happy because they solved a problem.
24:55
Uh, there were a number of problems that
24:57
Newtonian gravity couldn't, Couldn't help
25:00
with, which was solved by, uh,
25:03
Einsteinian gravity. So,
25:06
um, but that didn't seem to offer
25:08
any future benefits for
25:11
humankind. But here we are rather
25:14
more than 100 years later, 110 years later,
25:17
and we have, um,
25:20
tools which rely
25:22
absolutely on general relativity. And the one
25:25
I'm thinking of most commonly is, uh,
25:28
gps, uh, because our
25:30
position finding software, um,
25:34
simply would not work without general
25:36
relativity. You'd have errors in the region
25:38
of 10 kilometers, which is not kind of what
25:41
you want with GPS, but that took
25:44
100 years. And so Rennie, uh,
25:47
that's the sort of timescale, I think, on
25:50
which you have to be optimistic about the way
25:52
it might help humankind or life on Earth
25:55
generally. Because if we become
25:57
responsible, um, a responsible species
26:00
on our planet, we're going to help the whole
26:02
planet if we, if we live sustainably and
26:06
live, um, alongside, uh, all our
26:08
companion organisms on this
26:10
planet. So, uh, yeah, so I think,
26:13
um, what you can't say is that it won't help
26:16
them. That's the thing. You can't say that it
26:19
will either. Uh, but there's a good
26:22
chance that in the same way that, um,
26:24
something as abstruse as general
26:27
relativity actually comes into everybody's
26:30
everyday life odd years later.
26:33
I think that's the model. And it's one reason
26:35
why deep research
26:38
like this is funded. It's why fundamental
26:40
research that is just knowledge for its own m
26:43
sake at the moment, why it's funded. Because
26:45
you never know what the spinoffs might be.
26:48
Andrew Dunkley: Absolutely. Uh, and you can look back in
26:50
history at some of the great discoveries and
26:52
how they've changed things
26:55
on Earth and have changed human life.
26:58
Um, I'm just trying to think of one.
27:01
Professor Fred Watson: Well, electricity for a start. Well, they.
27:04
Yeah, you know, it was just, um, physicists
27:06
playing around in the early 19th century. Oh,
27:09
this is really interesting. Um, nobody ever
27:11
thought we'd use it like we do today.
27:14
Andrew Dunkley: I suppose one of The. This is probably a
27:18
fundamental example. Um, as we learn
27:21
things, we learn things, so
27:24
it expands our minds, expands our
27:26
inquisitiveness, it expands our intelligence,
27:30
enables humanity to understand
27:33
more about itself and its place in the
27:36
universe. You go back to 1543,
27:39
when Copernicus found that the Earth was
27:42
not the center of the universe.
27:45
I think he got shouted down pretty heavily
27:47
for that, but that's the truth. We know that
27:50
now. Uh, I can't remember who it was, but,
27:53
um, another thing that goes back quite a way,
27:56
when, uh, the discovery was made that our
27:59
sun is actually a star. I mean, for a long
28:01
time we didn't know that. You know,
28:04
it's. It's about knowledge as much as
28:06
anything, I think.
28:07
Professor Fred Watson: Yeah. Yep.
28:09
Andrew Dunkley: I love that one, though.
28:10
Professor Fred Watson: That's right. Yeah.
28:11
Andrew Dunkley: It's about.
28:11
Professor Fred Watson: The sun's Great.
28:12
Andrew Dunkley: Yeah. I think you can look it up. It's online
28:15
somewhere. I did it as a quiz question once
28:17
on the radio, and, um, got a great response
28:19
to that, because people just, in the modern
28:22
era never thought that there would have been
28:24
a time where people look at this, this hot
28:26
ball in the sky and go,
28:29
what is that? Um, and, you know, looking at
28:32
all the other stars, not making the
28:34
correlation. They just didn't know. It's, um.
28:37
It was incredible. So I suppose, Rennie,
28:39
it's, it's, it's about knowledge. It's about
28:42
expanding our understanding of life, the
28:44
universe and everything and not stopping at
28:47
42. Um, that's the way
28:50
I look at it.
28:52
Professor Fred Watson: I think you're. And I think you're absolutely
28:54
right. I think, um, you know, both. That's
28:56
two sides of the same thing. We're, we're.
28:59
But it's why we, why we do this sort of
29:01
thing. It's why is. We're a curious species
29:03
and.
29:04
Andrew Dunkley: Absolutely.
29:04
Professor Fred Watson: Knowledge is power.
29:05
Andrew Dunkley: Yeah, yeah, yeah. That's another thing. Yeah,
29:08
absolutely true, Rennie. Great question. Good
29:10
one for discussion and debate and keep, uh,
29:13
them coming. If you'd like to send questions
29:15
into us, um, you can do so through our
29:18
website, spacenutspodcast.com
29:20
spacenuts IO. They're the two URLs.
29:23
And, uh, while you're there, have a look
29:25
around. Uh, the AMA button at the top, Ask
29:28
me Anything is where you send your questions.
29:30
Ask me anything, text or audio. Don't forget
29:33
to tell us who you are and where you're from.
29:35
And, uh, you might want to click on the
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Support our podcast button, uh, and
29:41
help us out if you so desire. Never,
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ever going to make it mandatory. But, uh,
29:46
there are advantages to becoming
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a supporter, uh, of the podcast, so
29:52
check that out as well and visit the shop
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while you're there. That also helps us buy a
29:56
sticker, buy a cap, buy a shirt, buy
29:59
whatever. We should have Space Nut sunscreen.
30:02
You know, it would make sense. Anyway,
30:05
uh, you can do it all on our website. Fred,
30:07
thank you so much. Always a pleasure.
30:11
Professor Fred Watson: Good to talk, Andrew. And, um, I'm sure we'll
30:13
do it again soon.
30:14
Andrew Dunkley: Yes, I'm sure we will. It, uh, could be a few
30:17
minutes, could be a week, who knows? Uh, and
30:19
Huw in the studio, thanks to him for doing
30:21
everything he does. We don't know what that
30:23
is, but we appreciate it. And from me, Andrew
30:25
Dunkley, thanks for your company. See you on
30:28
the next episode of Space Nuts.
30:29
Professor Fred Watson: Bye. Bye.
30:31
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