Are you ready to have your understanding of the universe redefined? Picture this: a renowned expert advisor on dark and quiet skies, engaged in international cooperation at the United Nations, suddenly encounters a groundbreaking discovery that could revolutionize our perception of space and time. This unexpected twist in the story opens up a whole new world of possibilities, hinting at a connection between black holes and dark energy that could change everything we thought we knew about the cosmos. Stay tuned to find out more about this mind-boggling revelation.
In this episode, you will be able to:
· Explore the mysteries of black holes and dark energy to unlock the secrets of the universe. · Understand the mind-bending concept of the universe's expansion and its implications for the future of space exploration.
· Delve into the dangers posed by rubble pile asteroids and the potential impact on life on Earth.
· Discover the fascinating process of magnetic fields escaping from black holes and its significance in our understanding of the cosmos.
· Uncover the potential of artificial gravity and nuclear fusion, offering a glimpse into the future of space travel and habitation.
'Gravity and acceleration are equivalent. We can generate an acceleration by having a rotating wheel, exactly as in 2001, a space odyssey.' - Fred Watson
The resources mentioned in this episode are:
· Visit the Space Nuts website to submit your own voice question or text question for the podcast.
· Check out the Space Nuts shop on their website for space-themed merchandise and support the podcast.
· Become a patron of Space Nuts to support the show and gain access to exclusive benefits. · Listen to the Space Nuts podcast on various platforms including Apple Podcasts, Google Podcasts, Spotify, and iHeartRadio.
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00:00:00
Hi, Andrew Dunkley here and, just wanna say thank you for
00:00:03
listening to Space Nuts throughout 2023 Fred and I are
00:00:07
taking, just a couple of weeks off. But we will be back early
00:00:11
January. In the meantime, here's a repeat episode from early
00:00:16
2023. 1 of our Q and A episodes, Space Nuts. Hi there. Thanks for
00:00:22
joining us.
00:00:23
My name is Andrew Dudley, the host of Space Nuts. It's good to
00:00:26
have your company on yet another episode. Now, coming up on this
00:00:30
episode, we'll catch up with Professor Fred Watson strangely
00:00:33
enough because he's not in Australia at the moment.
00:00:36
He's somewhere on the other side of the world talking to very
00:00:39
important people, like his family and a few other from the
00:00:43
United Nations just either by, so we'll be talking about what
00:00:48
he's doing over there, but we'll also be focusing a lot of
00:00:51
attention on audience questions this week being episode 340.
00:00:55
Is there a source of dark energy that may well now be defined if
00:00:59
it is, it's huge news rubble, asteroid questions, magnetism,
00:01:04
the mass of photons, artificial gravity, nuclear fusion. It's
00:01:07
all coming up and Fred hasn't pre heard them. We're doing a
00:01:10
pot luck on Space Nuts today. Hope you can stick around nine
00:01:20
ignition sequence. Space Nuts. 54323454321. Space Nuts.
00:01:29
Astronauts report. It feels good.
00:01:32
And the man of the hour or the man who is joining us for this
00:01:35
hour, one or the other is Professor Fred Watson astronomer
00:01:38
at large. Hello, Fred. Hello, Andrew. Very good to see you
00:01:40
again down there in. So it's been very sunny. You're lucky to
00:01:45
be in Scotland because we've just come out of a heat wave,
00:01:49
temperatures for about 5456 days in a row up, around the 38 miles
00:01:57
well above the 100 in the old scale.
00:02:00
So we got a bit of a, we got a very, very significant, change
00:02:05
through on Thursday night that caused a bit of a problem around
00:02:09
the coast. Sydney included that I was taking a photo of the dust
00:02:17
as it rose up around town, as the, the, the, the southerly
00:02:20
buster as we call them, blew through. And I actually snapped
00:02:24
the camera at the exact moment of a lightning bolt. So I got a,
00:02:28
yeah, it was pretty cool.
00:02:32
Yeah, I, I'll send it to you. But, it's, it's been very warm
00:02:37
but not so where you are. If you take off the 30 from your
00:02:40
temperature. That's about all we've got here.
00:02:45
So I'm in Body Scotland at the moment. As you said, I'm staying
00:02:48
visiting my family. I'll be briefly, but I'm visiting my
00:02:52
family, which is a delight. Very nice. But preceding that you've
00:02:57
spent a couple of weeks talking to people from is it Copus? Yes.
00:03:02
The United Nations Committee that is looking at the Peaceful
00:03:07
Uses of outer space.
00:03:09
That's correct. So, this is United Nations 101. United
00:03:16
Nations has as one of its offices, something called Yusa
00:03:22
which stands for the United Nations Office Of Outer Space
00:03:25
Affairs. And within Unisa is a committee which is the Committee
00:03:32
On The Peaceful Uses Of Outer Space Or Cop was and co has a
00:03:38
subcomittee which is called the scientific and technical
00:03:43
sub-committee.
00:03:44
And that is what I was at. So the last two weeks oh sorry, the
00:03:49
first two week in February, there was the annual meeting of
00:03:54
the Science And Technical Sub-Committee Of COO. And this
00:03:59
was my first experience of being in that meeting.
00:04:04
I was part of Australia's delegation, a small delegation
00:04:09
of Australians attending. And I was there as an expert advisor
00:04:13
on dark and quiet skies, which of course, are very big in the
00:04:18
hearts of astronomers. I, I did say it was my first meeting.
00:04:22
That's not quite true because I attended quite a lot of cop was
00:04:26
virtually last year.
00:04:27
But it's certainly the first time I was there in person. The
00:04:30
first time I could see the interaction between the
00:04:33
different nationalities, the different nations represented by
00:04:37
K was, and also the first time I could see the process of how you
00:04:41
achieve consensus among a very disparate groups of group of
00:04:45
nations with different ideas.
00:04:48
I had the great privilege of presenting Australia's position
00:04:53
on dark and quiet skies, which is essentially something to the
00:04:57
effect that we recognize that you know, space in particular,
00:05:01
the idea of satellite constellations for for internet
00:05:05
access on Earth, that space is very important that these
00:05:08
satellite constellations are an important aspect of our future
00:05:12
human life.
00:05:14
But at the same time, Australia has invested considerable
00:05:18
amounts in astronomical infrastructure and doesn't want
00:05:21
space constellations to get in the way.
00:05:23
And so, that's really the nub of the issue, this balance between
00:05:30
what the space industry wants and what we want from the space
00:05:33
industry and what we want to protect in terms of dark and
00:05:36
quiet skies. And my view is pretty optimistic about this,
00:05:40
especially as we see the industry itself responding to
00:05:43
the concerns of astronomers.
00:05:44
So that was what took up a lot of my time during the two weeks
00:05:49
of the copper subcomittee meeting last week and the week
00:05:51
before. Yeah, I thought when it sort of focused on peaceful use.
00:06:00
They, they were going to be discussing, you know, not
00:06:03
putting weaponry in space, that 's not part of it. But, yes and
00:06:09
no.
00:06:10
I it's part of the, the assumption, the underlying
00:06:13
assumption of the discussions of this committee that it would all
00:06:17
be about peaceful uses. So setting aside the possible
00:06:21
military uses of outer space, which are a very different
00:06:25
thing, but I have to say that that idea did raise its head
00:06:29
several times during the committee.
00:06:31
But the committee is all about the peaceful uses about this
00:06:35
place. Well, I suppose with Vladimir Putin announcing that
00:06:39
they're willing to ditch the nuclear non proliferate
00:06:44
proliferation treaty in the wake of the US support for Ukraine,
00:06:49
that space would come into play as a potential launching ground
00:06:54
if you like.
00:06:54
So. Yeah, it's a hot topic but the peaceful use of space, we've
00:07:01
got a lot more private entities getting up there and it's
00:07:05
getting very busy as we've said before. That's right. And that's
00:07:08
the concern.
00:07:09
That's the real concern about this of this committee, despite
00:07:12
the fact that that shadow that you just mentioned, certainly
00:07:15
cast itself over the committee and it did. Yes, it certainly
00:07:20
made big news around here. All right. And it's not over, you've
00:07:23
got more work to do before you get back home, haven't you? Yes,
00:07:26
indeed.
00:07:26
There's a, a conference on a, on a, a much more scientific level,
00:07:31
there is a conference which is all about the future use of
00:07:35
surveys, big surveys in astronomy and in particular,
00:07:39
coordinating optical surveys. Invisible line with the European
00:07:43
Southern Observatory being one of the hosts of this meeting and
00:07:47
the radio services with the square kilometer array
00:07:49
observatory being the other host.
00:07:52
And by the way, just incidentally, I briefly passed
00:07:56
by the headquarters of the square kilometer array
00:08:00
observatory yesterday at Jo Old Bank in the north of England.
00:08:04
Yeah, I didn't, I didn't go in and say I'm the astronomer at
00:08:08
large or anything. I went and had a cup of coffee instead.
00:08:14
Yeah. Yeah. It's an amazing facility though that it is job
00:08:18
is spectacular. That's true.
00:08:21
Now, Fred, we were going to discuss this breaking news, I
00:08:25
suppose it's certainly caught my attention over the last few days
00:08:30
and that is the potential for the discovery of a source for
00:08:35
dark energy. But it's also been brought up in a question. So I
00:08:39
think we might go straight to the question then you and I can
00:08:43
discuss it after that.
00:08:44
This one comes from Daniel. Hi, Andrew and Fred. This is Daniel
00:08:48
from Adelaide. I have a theory that brings together all of your
00:08:51
favorite topics. Could black holes be the source for dark
00:08:54
matter and dark energy.
00:08:56
Could black holes suck up normal matter and energy and somehow
00:08:59
convert them to dark matter and dark energy and then spit them
00:09:02
back out, there's theories like Hawking Radiation and the
00:09:05
information paradox, which talk about how things can get out of
00:09:08
a black hole. But they've never been observed. Maybe it's
00:09:11
because they relate to dark matter and dark energy, which we
00:09:14
also haven't observed.
00:09:15
And here's why I think this could be a thing. So for dark
00:09:18
matter, when it gets spit out, it could be gravitationally
00:09:20
bound to the black hole and not go very far.
00:09:23
And we already know that dark matter comes in Galaxies and
00:09:26
around black holes, the dark energy perhaps it gets spit out
00:09:29
faster than light, which is why it can escape the black hole's
00:09:32
gravitational pull and could be why it's expanding the universe
00:09:36
and it's accelerating because as more and more black holes are
00:09:39
created, more dark energy is being released. And for both
00:09:43
that being fast and light is why we can't observe them.
00:09:46
Yeah, this is no doubt, a crazy theory that won't stand the Fred
00:09:48
test, but just wanted to ask the question of the show guys.
00:09:52
Thanks, thanks Daniel. Well, interestingly enough, what you
00:09:56
have just theorized may well be true. So there's a Nobel Prize
00:10:00
headed your way. Just keep an eye on the on your letterbox
00:10:05
because that's sure to arrive.
00:10:07
Great stuff, Daniel. And you are in a sense ahead of the curve
00:10:10
there because for the first time we've seen this week, a paper, a
00:10:17
scientific paper that exactly does that links black coal with
00:10:22
dark energy, not with dark matter. But with dark energy.
00:10:26
Now, what is different from the Daniel theory is the mechanism
00:10:30
for this?
00:10:30
It doesn't involve things being spat out of black holes at the
00:10:33
speed of light or anything of that kind. It's simply an
00:10:36
observation that has been made that turns out to give you a
00:10:42
possible explanation for the dark energy that we believe
00:10:47
fills the universe and is causing the universe to expand,
00:10:50
but ever more rapidly.
00:10:53
And it comes about by a series of observations made by a quite
00:11:01
a large team of 17 researchers, nine countries led by the
00:11:05
University Of Hawaii, but including British scientists as
00:11:08
well, which look at the way black holes evolve over time.
00:11:14
And what they've done is they've looked at black holes which are
00:11:21
in the early universe.
00:11:22
So that what we do is look back look out for to, to very distant
00:11:27
Galaxies and look at these black holes in the early universe. We
00:11:32
can see how energetic they are and you know how much they're
00:11:35
gobbling up material around them. But then to look much
00:11:41
later in the universe.
00:11:42
In other words, to more recent times, to look at Galaxies that
00:11:46
we believe have run out of the fuel that would provide the
00:11:51
black hole with you, you know, you know, the meals it requires,
00:11:55
that's the stars and gas that would surround the, the black
00:11:59
hole itself and actually cause the black hole to be to increase
00:12:04
in mass and become energetic.
00:12:05
So, the bottom line with this is that those recent observe the
00:12:11
observations of, of black holes as we see them recently. And
00:12:15
these are all supermassive black holes in the centers of
00:12:17
Galaxies. They are much bigger than they ought to be.
00:12:23
They're something like up to 20 times more massive than you
00:12:28
would expect them to be just from the, the idea of these
00:12:33
black holes accreting or gobbling up material. And so,
00:12:39
that is something that you can't explain the fact that they're up
00:12:44
to 20 times larger than they were in the early universe. The
00:12:48
equivalent types of Galaxies you can't explain by what you might
00:12:53
call normal astrophysical processes.
00:12:54
That's to say the accretion. And what they what these scientists
00:12:59
are drawing from that observation is that there is
00:13:04
some connection and it's being called cosmological coupling.
00:13:09
There is some connection between the black hole itself and what's
00:13:15
called its vacuum energy vacuum energy being the essentially the
00:13:21
energy of space itself.
00:13:23
So what they're saying is that black holes themselves generate
00:13:29
an energy that is somehow coupled to the expansion of the
00:13:33
universe so that this energy increases in mass as the
00:13:36
universe expands. And that maybe that is the source of dark
00:13:43
energy.
00:13:43
And in fact, the reason why they make that link is that the the
00:13:48
idea of this coupled energy from black holes going into the
00:13:52
universe itself, actually, when you do the calculations as to
00:13:56
how much vacuum energy there should be in a black hole and
00:14:00
look at the accelerated expansion of the universe, you
00:14:03
get the same so the black holes can provide the energy required
00:14:09
for the universe's expansion to accelerate.
00:14:13
And that's the bottom line with this with this work, I'm gonna
00:14:18
say a little bit from the study 's first author, Duncan Farr of
00:14:23
the University Of Hawaii. He is somebody who used to be at
00:14:29
Imperial College in London.
00:14:32
He's, he, we can quote what he said. He says we are really
00:14:35
saying two things at once that there is evidence that typical
00:14:39
black hole solutions don't work for you on long, long time
00:14:44
scale. And we have the first proposed astrophysical source
00:14:48
for dark energy.
00:14:50
What that means though is not that other people haven't
00:14:52
proposed sources for dark energy, but that this is the
00:14:56
first observational paper where we're not adding, adding
00:14:59
anything new to the universe as a source for dark energy. Black
00:15:03
holes in Einstein's theory of gravity are the dark energy.
00:15:08
In other words, if I can put that in a different way, We, we
00:15:12
don't, we don't need to look at you know, unusual sources of
00:15:16
energy that might be making the universe expand more rapidly. It
00:15:20
is actually coming from the black holes themselves, which we
00:15:24
understand at least at some level. This, I think potentially
00:15:29
is extremely exciting.
00:15:31
Andrew you and I have talked many, many times about black
00:15:34
about sorry, the, well, both black holes and the dark energy
00:15:37
but to link them together may well be something that might
00:15:41
result one day in a Nobel Prize watch this space. Yeah. What,
00:15:45
what's your letterbox, Daniel?
00:15:49
You said it first. But I guess the hard part is how do you
00:15:54
prove it? Yeah. So you've got to I I mean, in a sense, this is
00:16:00
laying down the first layer of proof because this comes from
00:16:03
observations.
00:16:04
The fact that when you observe black holes in the early
00:16:07
universe, black holes in today's universe, There is a mismatch in
00:16:13
what you expect their masses to be that they are 20 times up to
00:16:16
20 times more massive than what they should be if all they're
00:16:19
doing is accreting material. And so that is a really interesting
00:16:25
step. Now, my expectation, Andrew is that this will be
00:16:28
challenged by other astrophysicists.
00:16:31
And we might see a bit of detail in the challenges that perhaps
00:16:35
have been missed by these authors, but it's certainly a
00:16:38
very interesting first step in perhaps a real understanding of
00:16:42
what dark energy is all about. Indeed.
00:16:45
Yeah, it'd be extraordinary, but it sort of prompts a question in
00:16:49
my mind if black holes are responsible for the production
00:16:52
of dark energy, which is also responsible for the ever
00:16:55
increasing expansion and acceleration of the universe
00:17:00
itself. When all the black holes die, will we have a gab gibb,
00:17:05
maybe a gab G world or the big crunch as it's sometimes known?
00:17:11
Yeah. So that's a, this is the, that is a really good question
00:17:17
and my guess is the answer is no. And the reason for that is
00:17:21
that yes, black holes do evaporate. Because that's what
00:17:26
Hawking Radiation does, but they evaporate on hugely long time
00:17:31
scale.
00:17:32
And so I don't think you can wait that long. Because before
00:17:35
then you might have had the big rip, where the fabric of space
00:17:39
itself is torn apart by the expansion of the inhibits there.
00:17:44
It is. All right, just like blowing up a balloon and they
00:17:47
eventually have a big rip.
00:17:50
And my granddaughter Harry's going to be blowing up a lot of
00:17:53
balloons today because she turns 40, fantastic. Happy birthday,
00:17:56
Harry.
00:17:58
And thank you Daniel for your insightful question. You've
00:18:01
actually hit the nail on the head of some news that, only
00:18:06
came out in the last couple of days. This is Space Nuts. Andrew
00:18:10
Dunkley here with Professor Fred Watson and you're listening to
00:18:20
Space Nuts, the podcast about astronomy and space science with
00:18:24
Andrew Dunkley and Professor Fred Watson.
00:18:27
Now, Fred, we might as well continue to, load the audience
00:18:31
with questions we got, when we appealed for more questions. A
00:18:34
few, episodes passed, we, we got inundated and some of them are
00:18:39
sort of looking at things we've talked about recently, including
00:18:43
Andrew.
00:18:45
Hello, Fred and Andrew. Great episode. I'm really enjoying the
00:18:49
latest one. But I have paused it because I had a burning question
00:18:54
after your item about the rubble pile asteroids and how long
00:18:58
lived they are very, very fascinating.
00:19:03
I'm wondering if, hello, I don't know what the different danger
00:19:08
level is from rubble pile asteroids versus the solid ones.
00:19:13
And just wondering, shouldn't a rubble pile asteroid build up a
00:19:18
lot more than a big one and thus potentially be less damaging
00:19:24
anyway, fascinated to hear your answer to that one and keep up
00:19:27
the great work guys thoroughly enjoy it being listening from
00:19:30
the very early days.
00:19:31
This is Andrew from Melbourne, by the way. Cheers. Bye bye.
00:19:35
Thank you, Andrew. I hope you're avoiding those grass fires. That
00:19:37
's another thing that's happening at the moment now,
00:19:39
grass fires, Victoria and north of Melbourne.
00:19:42
So, yes, not a place at the moment, but yeah, good question.
00:19:46
We talked about those, those rubble asteroids recently and we
00:19:50
might recap on what they are. But I mean, in short, they are a
00:19:53
con type of asteroid but it turns out they're, they're tough
00:19:57
as nails. That's right. And this came from, this work came from
00:20:03
the P buser spacecraft with the samples brought back from
00:20:07
asteroid Ryuu, which as we know is a rubble pile asteroid.
00:20:10
It's a pile of debris. And it was the careful analysis of
00:20:16
crystals within those samples that gave rise to the idea that
00:20:22
rubble pile asteroids last a lot longer than what you might call
00:20:27
monolithic asteroids, asteroids are one chunk of material.
00:20:31
That was the result of the, of the isotope measurements and the
00:20:34
crystallography. And the inference of that was that maybe
00:20:41
they are harder to destroy that they kind of behave in a springy
00:20:47
fashion. If they're clouded by something else, they act like
00:20:50
what you might call the giant space cushion.
00:20:52
In fact, I think that's a quote from one of the authors of that,
00:20:55
of that paper. And so, that giant space cushion takes a blow
00:21:00
but doesn't destroy the rubble pile asteroid, which is exactly
00:21:05
the opposite of what you would expect to happen. You'd think a
00:21:08
pile of debris, you hit it with something else would just fly
00:21:10
apart, but that is apparently not the case.
00:21:12
So the the other inference from that was that perhaps because
00:21:17
these asteroids may well be very long lived, perhaps there are
00:21:20
more of them than we expected. And the good news story as an
00:21:25
aspect of this was that a rubble pile asteroid might well respond
00:21:31
well to the shockwave of a nearby nuclear blast if you need
00:21:35
it to detect one.
00:21:36
And just going back Andrew to my, time with the United
00:21:41
Nations, last week and the week before I also had the great
00:21:45
pleasure of sitting in on a meeting of the international
00:21:48
asteroid Warning Network. Who think about exactly this sort of
00:21:53
thing.
00:21:54
And the rubber pile idea was one that certainly was discussed
00:21:59
during this meeting that you might be able to use a, an
00:22:03
indirect nuclear blast to, to deflect one more readily than
00:22:06
you could a solid and monolithic one. And now that doesn't answer
00:22:11
Andrew's question, which is about how much does a rubble
00:22:15
pile, you know, disintegrate as it passes through the
00:22:18
atmosphere.
00:22:20
And my guess is that given the apparent resilience of these
00:22:26
rubber piles, it may well be that they would still behave
00:22:29
much the same way as a monolithic asteroid when they're
00:22:33
heated to, you know, high temperatures by their passage
00:22:37
through the atmosphere.
00:22:38
Of course, a big rubble pile asteroid would be an object of
00:22:41
considerable danger to the Earth because he's talking about
00:22:45
something that could, could clearly generate probably state
00:22:51
wide or may be even continent wide damage. Depending on the
00:22:55
size I'm talking thinking now about things of the order of 100
00:22:57
m across, I think. Yes. So I, I am studied the details of this.
00:23:03
I'm sure there are other people. In fact, some of the colleagues
00:23:06
I was speaking to in the International Asteroid Asteroid
00:23:09
Warning Network might well might well have thoughts on this. But
00:23:14
it's intuitively, I'd expect it would be bad news either way.
00:23:18
That's the bottom line if something was inbound of that
00:23:22
mass.
00:23:24
So, Andrew, if you hear of one heading towards Earth, don't go
00:23:28
out without your umbrella.
00:23:31
I thought it was a paper bag you were supposed to take with you
00:23:33
for things like that.
00:23:35
Probably that effective.
00:23:39
Yes, indeed, but great to hear from you, Andrew. But the answer
00:23:43
is sorry, it's still going to kill us all.
00:23:47
Hopefully the theory will fix it. That's right.
00:23:52
All right. Let's move on to our next question. This one comes
00:23:55
from Peter.
00:23:56
Hello, I'm Peter. I at the United States. I just finished
00:24:01
listening to an old episode called magnetism that you guys
00:24:05
did and I was wondering black holes, photons can't thieve the
00:24:12
event horizon of a black hole out to magnetic field lines and
00:24:18
out doesn't quite make sense.
00:24:22
Also the second question during the episode, Doctor Watson said
00:24:29
that the Magnetic North Pole of the Earth was wandering around,
00:24:37
that was probably somewhere in Siberia. I always understood
00:24:41
that the Magnetic North Pole was in the southern geographic pole
00:24:47
that the magnetic north of your compass needle points toward the
00:24:51
south so that the South Magnetic Pole was actually the north
00:24:57
geographical if I got that wrong.
00:25:00
Thanks guys. Great show. Alright. Thank you, Peter. What
00:25:03
I want to know is whether he was turning left or right. I I heard
00:25:07
a car indicator that depends which way the magnet was
00:25:11
pointing obviously of the road.
00:25:15
And yeah, so a double whammy magnetic fields and how the
00:25:22
magnetic fields escape the the sun when its gravity is so very
00:25:27
intense and everything falls back in. Is that what he meant?
00:25:30
Yeah. Well, yes, I think he was specifically referring to black
00:25:33
holes though as well. Which also have magnetism. It's a good
00:25:37
question actually.
00:25:40
The magnetic field around a black hole, is it escaping
00:25:45
through the event horizon or not? Because magnetism is
00:25:48
carried by photons which are subo towing particles, the
00:25:51
electromagnetic force carrier.
00:25:54
And my guess is that the magnetism must be created
00:26:00
outside the advent horizon, but I'm not enough of a black hole
00:26:04
specialist to know the answer to that.
00:26:06
So I might defer to my colleagues about that that
00:26:10
however, Peter's right about the, you know, the, the the
00:26:14
magnetic pole, we we we conventional refer to the north
00:26:21
magnetic poles of the Earth as being the one that's in the
00:26:24
northern hemisphere, even though it would be the south pole of
00:26:27
the magnet that would point towards it on a, on a, in a
00:26:31
magnetic compass. So, you, you're right to, to pick up on
00:26:35
that.
00:26:35
And in fact, I think we had that debate at the time. But what we
00:26:39
conventionally describe as the north bic pole is indeed in the
00:26:43
northern hemisphere of the Earth because it wouldn't make much
00:26:46
sense if the South Magnetic Pole was up there among the eyes, it
00:26:51
wouldn't really would it.
00:26:53
What happens when the magnetic field of the Earth flips? Is
00:26:57
that going to mess all that up? Yeah. Well, that's right. It
00:26:59
means that you make the point the way I think we should all
00:27:03
look forward to that when it might happen within the next
00:27:06
2000 years or so. Right? Ok. Hold your breath. So the answer
00:27:11
to your question Peter was don't know. And yes, that was it.
00:27:20
Well, it's better than yes and don't know.
00:27:26
Wait. Alright, thanks Peter. Great to hear from you. And
00:27:30
yeah, we'll, we'll yeah, I suppose we, yeah, as Fred said,
00:27:35
we'll, we'll wait till the flip happens and then everything will
00:27:37
be sorted out. This is Space Nuts nuts. Now, this question
00:27:46
that comes from Alan Fred, you touched on in answering Peter's
00:27:51
question. This is actually about photons.
00:27:55
Hi Ellen from Copenhagen Denmark. I just learned from
00:27:59
another podcast that Poons carry no mass.
00:28:04
Then how can they carry energy when E equals MC square EE. Yes,
00:28:13
indeed. That's a good question. Now, you talked about what
00:28:16
photons carried in the previous answer. So, if they've got no
00:28:22
mass, how can they carry something? That's, that's a good
00:28:24
question. What they do have is what's called a rest mass.
00:28:29
Because you can't, you can't stop, well, you can actually
00:28:33
stop a photon. But that needs special, special sorts of
00:28:37
equipment, but they don't have a rest mass. And so they do carry
00:28:41
energy exactly in accordance with other equations, a bit like
00:28:48
a E equals MC squared. So photons carry electromagnetic
00:28:52
energy and indeed, magnetism is a, is a form of that.
00:28:55
And so it's carried by photons as we were just saying, but the,
00:29:01
the, the, the, the deciding thing is clearly photons do have
00:29:07
energy. And in fact, when we talk about the wavelength of
00:29:11
light, for example, the, the smaller the wavelength, the
00:29:14
higher the energy.
00:29:15
And so when you get to to things like gamma rays and X rays,
00:29:21
these very high energy photons, then we just discuss them in
00:29:26
terms of their energy rather than talking about wavelengths
00:29:30
or frequencies at all, just the amount of energy that that photo
00:29:33
carries. But it, but the bottom line Alan and it's a, it's a
00:29:36
great question and it probably sounds like a glib answer but it
00:29:40
's that you, if you stop the photo, it doesn't have mass.
00:29:44
That's the bottom line. No. Well, it's interesting, you
00:29:48
should say if you could stop a photon, I, I read an article the
00:29:51
other day there's, I can't think of the scientist's name but she
00:29:54
's been playing with light and she's actually been successful
00:29:58
in manipulating light and affecting photons and, and she
00:30:02
actually reduced the speed of light to 17 m per second in a
00:30:07
lab which II, I just can't comprehend that.
00:30:11
And she said she could even save it up and use it later. Yes. I
00:30:15
can't get my head around that.
00:30:17
And neither can I and I know these experiments take place and
00:30:22
they use they, they basically use sort of highly focused
00:30:28
clusters of, of atomic nuclei to interact with the photons that
00:30:34
it's a field that I don't know too much about. But it's a great
00:30:37
area of physics. And you're quite right that you you can
00:30:40
slow down photons to have a speed of light that is very
00:30:44
slow. Indeed.
00:30:46
Yeah, but it's, I think it needs very special manipulation of the
00:30:50
Libra by you know, by focusing, as I said, focusing particles
00:30:58
subatomic particles in such a way that they interact with the
00:31:01
photon and slow it down.
00:31:03
I suppose those kinds of experiments and those kinds of
00:31:07
achievements also help explain how light moves around the
00:31:10
universe and how we can still see things that happened so long
00:31:14
ago. Because of the manipulation of, of gravity and all the other
00:31:19
things that are affecting the light around the universe. So
00:31:22
that's correct.
00:31:23
And that's how you can see one thing happen three times because
00:31:26
of the, the light at different speeds due to gravitational
00:31:30
waves and or gravitational effects and the lensing and all,
00:31:34
all of those things lens. So it 's you know, you're quite right
00:31:39
sometimes you get a phenomenon that BB a burst of energy from
00:31:43
maybe a supernova explosion that takes different pathways around
00:31:46
the galaxy whose mass is acting as a lens.
00:31:50
And so you get perhaps three different images of the same
00:31:52
thing. And there's been some remarkable work on this kind of
00:31:56
thing, including predicting when a supernova explosion will be
00:31:59
seen. I think that's happened and the prediction turned out to
00:32:03
be correct because it had already been seen by a different
00:32:07
pathway of light going around in another object.
00:32:11
Indeed. Alright. Thank you, Alan. Our next question comes
00:32:16
from Robert. This is a bit of an old chestnut, but I, I love
00:32:19
talking about this a little further and this is Rob from
00:32:23
Islands. It's small village than Amsterdam. Love the podcast ruby
00:32:27
f. Really interesting this, you recommend I have a question
00:32:33
about artificial properties guys. How far along are we?
00:32:37
Because it's really important for you to be able to go through
00:32:40
interstellar space. Now, nobody has artificial gravity. I know
00:32:44
the big central football force, it will push it down instead
00:32:48
except the same art of gravity. They will need that huge lo of r
00:32:52
in space to make this force happen for people to make them,
00:32:56
you know, healthily get to a very far destination.
00:33:00
So that's my question. Thank you so much for taking the time and
00:33:04
please keep doing what you're doing. Thank you. We will try to
00:33:08
keep doing what we're doing, which we're doing right now. But
00:33:11
thank you, Robert. Yeah, artificial gravity. It comes up
00:33:14
from time to time. It's there's a long way to go before we, when
00:33:18
we get there, I think. Yes.
00:33:23
Although there is work on it and I think I might have said this
00:33:26
before to Andrew on Space Nuts.
00:33:29
We had a visit several years ago. It's about four years ago
00:33:33
now, I think from Linda Spilker who was the Cassini project
00:33:38
scientist, the Cassini spacecraft. And her husband runs
00:33:44
a company that is working on artificial gravity solutions for
00:33:48
spacecraft. And I think when suddenly when we spoke to him,
00:33:52
he doctor Spilker, male, Doctor Spilker, rather than female.
00:33:56
Doctor Spilker, he had a contract with a, an agency
00:34:03
usually known as NASA. So he he was kind of working a lot, you
00:34:08
know, in a high flying regions and I had a quite a long chat
00:34:12
with him about artificial gravity caused by the
00:34:16
acceleration. That's because gravity, you know, is equivalent
00:34:20
to acceleration. We, we can get and generate an acceleration by
00:34:25
having a rotating wheel. Exactly as in 2001 a space Odyssey.
00:34:30
And the in the nuances of that are really interesting in that
00:34:37
there are only certain range of rotational speeds for which you
00:34:43
get something that simulates gravity without peculiar
00:34:47
effects. If you, if you have the thing rotating too quickly, or
00:34:51
you are you know, your, your wheel is too small, then you,
00:34:56
you're standing away outer edge of this wheel with your
00:34:59
artificial gravity.
00:35:00
But it tends to produce rotation effects in your brain to cause
00:35:05
nausea and have strange things. Like if you, you know, if you
00:35:09
drop a coin or something, the coin doesn't go straight
00:35:12
downwards ie outwards radially. It goes, yeah, goes off to the
00:35:15
side and that's very counterintuitive. But yeah,
00:35:19
this, this was where it was ongoing. So it is actually a
00:35:22
field of of activity within the excuse me, the astron community.
00:35:31
The just an aside year which is straying way off Robert's
00:35:36
question. But I think is really interesting. And again, this is
00:35:39
a news item that came out this week. But we usually associate
00:35:45
the idea of gravity and acceleration being equivalent
00:35:51
with Einstein because his equivalence principle was
00:35:55
something that was I think he, he realized that back in 1907,
00:36:02
it was after he published the Special theory of relativity in
00:36:05
1905.
00:36:06
But before he got to the to the general theory in 1915, it may
00:36:12
have been a little bit later than that. But he, he twigged
00:36:14
this point that gravity and acceleration are equivalent. He
00:36:19
called it the equivalence principle.
00:36:21
And it turns out that this recent research that has been
00:36:25
done by scientists from a number of universities including
00:36:31
Caltech, the California Institute Of Technology. That
00:36:35
show that Leonardo Da Vinci did an experiment that demonstrated
00:36:42
the same thing really very clever that Leonardo grasp the
00:36:47
idea that there is an acceleration which is the
00:36:51
equivalent of gravity.
00:36:53
And I think that's an extraordinary thing for, you
00:36:56
know, somebody to to to, to realize in the, in the early
00:37:01
16th century. It, it was really, it's usually Galileo we think of
00:37:06
as laying the groundwork of that equivalence. But it looks as
00:37:10
though Leonardo got, got there first.
00:37:13
So Isaac Newton should have just eaten the apple. I think he did
00:37:17
actually in the end. But you can you can follow this up.
00:37:20
Actually, there's a paper which is in a journal called Leonardo.
00:37:25
It's called Leonardo Da Vinci's visualization of gravity as a
00:37:29
form of acceleration.
00:37:31
Yeah, he was way ahead of his time, wasn't? He certainly was
00:37:36
all this is space Ns Andrew Dunley with Fred Watson.
00:37:44
You too could feel what it means to win a share in Lotto's $30
00:37:49
million mega draw this Saturday. Hurry, get your ticket today.
00:37:54
Wouldn't it be nice?
00:37:59
Space notes. Now, we might squeeze in one or two more
00:38:02
questions, Fred. This one again, looks at something we've talked
00:38:08
about before. This is Tom.
00:38:11
Hello, Fred and Andrew. This is Tom from Minnesota and I just
00:38:14
wanted to congratulate the two of you on being selected to be
00:38:17
cryogenically frozen until nuclear fusion is ready to be
00:38:22
integrated into space exploration.
00:38:25
Now, when we saw you guys out, you're going to have the honor
00:38:27
of getting to pick where the first nuclear fusion powered
00:38:31
rocket is going to go. And I am so curious to hear what you
00:38:35
think might be the goals of that first mission. Love the show.
00:38:38
Thanks so much.
00:38:40
Thank you, Tom. Interesting way to ask a question. I yeah, we've
00:38:44
talked about long haul travel in space and, and ways to propel
00:38:48
ourselves. Sales light sails. We've talked about, you know,
00:38:54
traditional rockets just not holding their water, so to
00:38:57
speak. But nuclear fusion has been talked about as a potential
00:39:03
way of, of traveling at pace long distance in space.
00:39:09
And that's that's what he's alluding to. So, and, and I know
00:39:14
they're working on all sorts of options, Fred and, and the time
00:39:18
will come when they, when they find a way to, reach reasonable
00:39:22
speeds because that's the, the, the, the challenge, isn't it,
00:39:25
get, getting fast enough to get somewhere before we all, you
00:39:29
know, drop off the Tweet.
00:39:33
Where would we go first? I, I, that is, that is the question.
00:39:37
And my first thought when I, when I, listen to Tom's
00:39:42
question, my, my first thought would be Alpha Centauri.
00:39:46
I mean, you go to the nearest star that's not the sun,
00:39:49
wouldn't, would you not? I think you'd be, I, I actually think
00:39:53
you'd be going even nearer than that. I think you'd try out
00:39:56
first on the moon. Oh, ok.
00:40:00
Quickly you can get that. This is really interesting beyond the
00:40:04
phase. Yes, beyond the testing phase. Tom Tom's quite right.
00:40:08
But, you might be surprised or you may not be surprised to hear
00:40:12
this, Andrew, but, there is a working group on nuclear power
00:40:16
sources in space which had several meetings during the
00:40:20
meeting, the Kuo subcomittee meeting that I was at a couple
00:40:24
of weeks ago.
00:40:25
And that working group was chaired by a very eminent
00:40:28
British physicist, somebody who 's worked with nuclear power
00:40:33
sources over many decades. Doctor Sam Harbisson, who
00:40:36
actually resigned, retired from, from the head of the lead of the
00:40:41
working group.
00:40:41
But I sat in on some of those sessions really interesting the
00:40:45
kind of things that are being discussed in terms of nuclear
00:40:48
power sources in space and fusion, of course, is always the
00:40:53
Holy grail. My feeling was that nuclear fusion as a power source
00:40:58
in space is not seen as, as the, the, the, the panacea that you
00:41:05
might think it is, it doesn't solve all the problems.
00:41:08
It just gives you a bit more of a string to your bow. But, I,
00:41:12
yeah, you know, I, I'm, I'd be inclined to agree with you that
00:41:15
if, if the, if you did have AAA new form of energy, a new form
00:41:22
of propulsion that was gonna get you somewhere pretty quickly,
00:41:26
then Alpha Centauri would definitely be a worthwhile
00:41:29
target.
00:41:30
It's still gonna take you, no fewer than 4.5, 3rd years to get
00:41:35
there because that's how long light light it takes to get
00:41:39
there or to, to, to come back. But, yeah, I, I think that's a
00:41:43
pretty good guess and I'd go along with you, Andrew. Ok.
00:41:48
Tom. Agrees. Yes. And just keep working on your nuclear fusion
00:41:53
generator to, and let us know when it's done and we'll, I
00:41:57
think we can just throw in one very quick, question from a
00:42:02
YouTube listener, Emil from Denmark who follows us on
00:42:05
YouTube. He said, I don't know if you ever read YouTube
00:42:10
comments? Obviously, somebody did.
00:42:11
He said, but I've always wondered if the atmosphere of
00:42:14
the Earth is hiding colors of space like, the effects from the
00:42:19
sun which seems yellow but is actually white question Mark.
00:42:25
Also how come gas is blue at 2000, I'm assuming degrees
00:42:30
Kelvin and the sun is yellow at 6000, but you need 10.
00:42:33
Kelvin to get a blue star. Hope life is good and glad you're
00:42:38
uploading to Spotify. I am too.
00:42:41
Yeah. Ok. So is is the Earth's atmosphere hiding the true
00:42:46
colors of the universe from us. Yes, at some level it is. And
00:42:50
exactly as Emil said, its effect is to redden light very slightly
00:42:57
to, to you know, the the scattering of the atmosphere
00:43:01
removes the blue light from the atmosphere.
00:43:03
So you get something redder and the same is true with light
00:43:07
passing through dust clouds in in the distant universe, we can
00:43:10
work out by how much reddening there is, how much dust there is
00:43:14
around it so that there is this modification of columns.
00:43:19
The second part of his question is very interesting. So that
00:43:23
blue so that a AAA star like the sun, which is white is at about
00:43:31
5000 °C or Calvin actually, which adds a further 273 degrees
00:43:39
into it. If but a star like Sirius is indeed at a much
00:43:46
higher temperature and looks bluish.
00:43:49
But that's different from the blue of a gas flame at 2000
00:43:53
degrees which is glowing blue because of the, the, the
00:43:57
basically the, the, the, the emission of light from different
00:44:00
gasses within the within the, within the, the, the flame, what
00:44:05
you're seeing with the star is what's called black body
00:44:07
radiation.
00:44:08
It is that it's as if the star was a completely black body and
00:44:12
you heat it to that particular temperature, that will be the
00:44:15
color that it would be. And that 's the, the same is true of the
00:44:18
sun.
00:44:20
So we, we, we, we're talking about two different physical
00:44:23
processes there that are giving you two different sets of color
00:44:26
and two different lots of bloomers if I can put it that
00:44:28
way. Well, OK, so a red dwarf would be what temperature? 2000,
00:44:34
300 thereabouts quite poor, the lower the temperature, the
00:44:37
redder.
00:44:39
Exactly. That's exactly so. And in fact, we in the lighting
00:44:44
industry, and you might know this because when you buy a,
00:44:48
often when you buy a, a light globe or a light bulb, you might
00:44:51
find something called the correlated co color temperature
00:44:55
ma T and it's a temperature in degrees Kelvin, which is
00:45:00
essentially a measure of the color of the, the light.
00:45:03
So something like 3000 Kelvin would be a, a warm ice. It would
00:45:07
be almost yellow in color, whereas something at five or
00:45:11
6000 Kelvin would be intensely white. And you know, have that
00:45:16
have that, that almost painful whiteness about it that we
00:45:19
sometimes see with, with le led headlines, for example, on cars
00:45:25
and D All right.
00:45:27
Great question from you, Emile. Thank you so much for getting in
00:45:31
touch with us. And hello to all our YouTube followers. We are
00:45:36
pretty well done, Fred. I will remind people if they do have
00:45:39
questions to send them to us via our website, Space Nuts,
00:45:42
podcast.com or Space Nuts dot IO. There are a couple of links
00:45:46
there.
00:45:46
You can, the A MA link at the top where you can send us text
00:45:49
or audio questions or rather the tab on the right that says, send
00:45:53
us your voice question. Don't forget to tell us who you are or
00:45:55
where you're from because we love to know. And, yeah, that
00:45:59
way you can get, stalked by somebody who listens. No, no,
00:46:03
no, there's nothing like that.
00:46:05
But yeah, it's always good to know who we're talking to. And,
00:46:09
while you're online, don't forget to check out the Space
00:46:12
Nuts shop on our web website. And if you're interested in
00:46:15
becoming a patron, you can look that up as well. And thank you
00:46:18
to all our patrons who have been supporting Space Nuts for such a
00:46:22
long time. Now, your support is certainly welcome and greatly
00:46:27
appreciated Fred.
00:46:29
We're done. Thank you so much from Bonnie Scotland. It's a
00:46:33
great pleasure. I I the new, and thank, thank you for for fitting
00:46:39
me in this week. Good to talk to you for finding the time because
00:46:43
I know it's well, it's half past 11 your time now, isn't it?
00:46:47
Something like that? That's correct. And you're about to go
00:46:50
to bed and I've only just got up.
00:46:53
Alright. We look forward to catching up with you soon. Fred.
00:46:56
Thank you. No problem Andrew. Good to talk. See you, see you
00:46:59
next time. Ok, Fred Watts, an astronomer at large part of the
00:47:02
team here at Space Nuts and thanks to Hugh in the studio who
00:47:06
didn't turn up today, but he'll turn up later and do all his
00:47:10
editing and coffee making and everything else.
00:47:13
From me, Andrew Dunkley. Thanks for your company. We look
00:47:15
forward to catching you again on the very next episode of Space
00:47:18
Nuts. Bye bye to the Nuts podcast available at Apple
00:47:26
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00:47:31
favorite podcast player. You can also stream on demand at
00:47:34
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00:47:39
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