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Moon Mysteries, Hubble Tension & the Kuiper Belt's Triple Surprise · Space Nuts: Astronomy Insights & Cosmic Discoveries

0:00
Professor Fred Watson: Hello again.
0:00
Andrew Dunkley: Andrew Dunkley here from Space Nuts, where
0:03
we talk astronomy and space science. Good to
0:05
have your company. Coming up on this episode,
0:08
we are, going to talk about the moon. It's
0:10
got a near side, it's got a far side, but
0:12
we're going to talk about the inside. it's,
0:15
discovery of the Grail mission.
0:18
which means what we're talking about is a
0:20
flesh wound. another Hubble tension. Think
0:23
about it. Another Hubble tension theory. And
0:26
we're talking evolution this time. And a
0:28
triple system in the Kuiper Belt. Belt. So
0:31
buckle up for this episode of space
0:34
nuts.
0:35
Voice Over Guy: 15 seconds. Guidance is internal.
0:37
10, 9. Ignition
0:40
sequence start. Space nuts. 5, 4, 3,
0:43
2. 1. 2, 3, 4, 5, 5, 4,
0:46
3, 2, 1. Space nuts. Astronauts
0:49
report it feels good. And back with us
0:52
again is Professor Fred Watson Watson,
0:54
astronomer at large. Hello, Fred.
0:56
Professor Fred Watson: Hello, Andrew. Hello. Took me in couple.
0:58
Couple of seconds. But I did get the.
1:00
Andrew Dunkley: To get the, flesh. The flesh wound. Flesh
1:02
wound. The Grail mission.
1:04
Professor Fred Watson: Only a flesh wound.
1:05
Andrew Dunkley: It's only a flesh wound.
1:06
Professor Fred Watson: That's right. no arms, no legs,
1:09
but nothing.
1:11
Andrew Dunkley: Flesh wound. so, yes, that I,
1:15
I can't help dad jokes and, and, and
1:19
I, I. When I do the presentations at golf on
1:21
Fridays, which has become my job somehow.
1:25
I always have to finish on a dad joke. It's
1:27
just become a thing.
1:28
Professor Fred Watson: Yes, yes, I'm sure it has.
1:31
Andrew Dunkley: The reputation continues to spread. we'll be
1:34
talking dad jokes in our next episode,
1:37
our Q A episode as well.
1:39
we should begin with this,
1:41
Grail mission and the findings of the moon's
1:44
unusual interior. This might
1:47
come as a surprise to some people.
1:50
Professor Fred Watson: Well, I think it does. Excuse me. I think it
1:53
did come as a surprise when the discovery was
1:55
made as well. These, are, scientists from
1:57
NASA and other institutions, missions.
2:01
yeah, let's do the dad joke first. The, It's
2:03
not Monty Python and the Holy Grail.
2:07
Grail stands for Gravity Recovery and
2:10
Interior Laboratory. And it was a mission,
2:14
which I guess it was more than. It's probably
2:16
a decade ago. it's a very, very
2:19
neat piece, of research. And
2:22
NASA, you know, the clever stuff that they do
2:24
is just unbelievable.
2:26
so what do you do if you want to sense the
2:29
gravity of, a planet that
2:32
you're flying over? You want to map out the
2:34
gravitational details. And by doing
2:37
that, you can work out what's underneath the
2:38
surface. because that's usually what
2:41
affects the gravity above the surface of
2:44
a planet. And I'm Talking now about really
2:48
minor, disorder, differences and
2:51
discrepancies in gravity, how the
2:54
Grail mission worked. and I'm kind of casting
2:57
my memory back now. two spacecraft,
3:00
in orbit around the Moon,
3:02
separate in the same. They're both in the
3:04
same orbit. They were separated, I think, by
3:07
about 200 kilometres, one in front of the
3:10
other. But the
3:12
distance between them could be detected
3:15
by microwave transmission
3:18
to well under a millimetre. I can't remember
3:21
what it was. It was a few microns, I think.
3:23
But this tiny, tiny difference between
3:26
the position of the two spacecraft, you can
3:29
measure it, by these microwave signals. And
3:32
so as the two spacecraft go around the moon,
3:35
their separation changes slightly as a
3:38
result of the gravitational force,
3:40
gravitational pull of the terrain beneath
3:43
them. and it actually is
3:46
a, really very sensitive way. I love the fact
3:49
that they rediscovered, something that we
3:52
talked about in the very earliest, history of
3:54
moon exploration. Back in the, Gemini and
3:57
Apollo era, back in the 19, 60s,
4:00
mass, cons, which were mass concentrations,
4:03
concentrations of mass that were unexpected
4:06
underneath the Moon's surface. They were
4:07
actually measured just by spacecraft that
4:10
were orbiting. Single spacecraft orbiting
4:13
the Moon. but, GRAIL actually mapped them out
4:15
in much more detail. We know a lot more about
4:17
these mascons now than we did before. But
4:20
what has happened, and by the way, I should
4:23
just mention one, I should have put this in
4:25
as a, As a quirky factoid, shouldn't I?
4:28
Flippant factoid that the two,
4:31
spacecraft, the two components of Grail. Do
4:33
you remember what they were called?
4:35
Andrew Dunkley: Oh, no.
4:38
Professor Fred Watson: Ebb and flow. And it came.
4:41
I think it was school kids who did that. If I
4:44
remember rightly, NASA sent out a competition
4:46
saying, we've got two spacecraft in orbit
4:47
around the Moon. What do you want to call
4:49
them? And they were called ebb and flow,
4:51
which is very, very nice indeed.
4:53
Anyway, ebb and flow, in combination,
4:56
measured, virtually the gravitational map of
4:59
the whole Moon. But what has
5:03
come to light is something a little bit
5:06
more subtle. these, researchers who've now
5:09
used these NASA data to deduce
5:12
that There's a, 2 to 3%
5:15
difference in the
5:18
ability of the lunar mantle. Now, that's
5:21
the layer below the crust. That's the
5:24
layer that surrounds the core of the Moon.
5:26
The ability of the mantle to
5:29
deform. So what you're
5:32
saying is there's a difference in sort of
5:35
flexibility from one side of the Moon to the
5:37
other. And remember, as we know The Moon
5:39
always faces the same side to Earth. and
5:42
so that's, you know, there's a different
5:44
gravitational pull on one side from what
5:46
there is on the other. but what they've
5:48
interpreted this difference as being,
5:51
they say it's symptomatic. The fact that
5:54
there's this difference in the Moon's mantles
5:57
ability to deform, to change its
6:00
shape. they say that is
6:03
best explained by the
6:05
temperature inside the mantle
6:09
on the near side being as much
6:11
as 170 degrees Celsius
6:14
hotter than what it is on the other side.
6:17
Wow, that's a side facing us. Yeah, it is.
6:19
It's not a small amount, it's not a few
6:21
degrees, it's a lot. and it's enough to
6:24
change the viscosity of the mantle, how
6:27
flexible it is. and so
6:29
that's the new finding that's come from
6:32
ebb and flow. And I think what they're saying
6:34
is that the spacecraft was in orbit for long
6:37
enough that it could detect differences in
6:40
the gravitational pull as it flew over the
6:42
same part of the Moon more than once. It
6:45
could see a difference in the gravitational
6:47
pull from one trip to another. So there's a
6:49
time dependent thing on it, and that's how
6:51
they know about the Moon's ability
6:54
to deform. I'm actually, interpreting that in
6:56
my own way. There's a nice
6:59
paper in Nature magazine, perhaps
7:02
one of the two leading journals for science
7:04
in the world, which has the title of thermal
7:07
asymmetry in the Moon's mantle inferred from
7:10
monthly tidal response.
7:12
Andrew Dunkley: Okay, so my question
7:14
straight up is, could that explain,
7:18
or does that explain why the near side
7:21
and the far side of the Moon are so
7:23
very different? when you're talking
7:25
topography, yeah, I.
7:27
Professor Fred Watson: Think it's the other way around. I suspect
7:29
the difference in topography is,
7:32
what causes the difference. Although they're
7:35
probably all mishmashed up,
7:39
into the same sort of thing.
7:42
But the Moon's nearside,
7:45
I think probably the way you've put it,
7:47
actually Andrew, is probably more correct.
7:49
The Moon's nearside, has had much
7:51
more volcanic activity than the far side.
7:54
This is between 3 and 4 billion years ago. It
7:57
was highly volcanically active, which is why
7:59
we've got all these lava flows on the near
8:01
side, which we see as the maria, the grey
8:04
patches on the Moon. but the
8:07
details of what these
8:09
researchers think, contributes to
8:13
the difference, in temperature,
8:15
they suggest I might actually, I think this
8:18
is Nature's press release So I might just
8:21
read straight from it.
8:24
they hypothesise that this thermal
8:27
difference could be sustained by radioactive
8:29
decay of thorium and titanium within the
8:32
moon's near side, which could be a
8:35
remnant of the volcanic activity that formed
8:37
the near side surface 3 to 4 billion years
8:40
ago.
8:42
Andrew Dunkley: That is really interesting. Yeah,
8:44
I'm fascinated
8:47
by a couple of things, that we're using old
8:49
data to make new discoveries. We've talked
8:51
about that in other studies that have more
8:54
papers that have been released in recent
8:56
years. also the fact that there's
8:59
effects on the moon that we see in
9:02
other parts of the solar system, with, with
9:04
variations in the way the moons
9:08
interact with their host planet for example.
9:11
I suppose.
9:12
Professor Fred Watson: Yes.
9:12
Andrew Dunkley: It's a similar situation is it not?
9:15
Professor Fred Watson: Yes, that's right. So you've got and in fact
9:17
most of these moons around, certainly the
9:19
giant planets are ah, which is where most of
9:22
the moons in the solar system are. there's
9:25
only three in the inner solar system. Ours
9:27
and Mars is two little satellites.
9:30
But places like Enceladus, Ganymede, perhaps
9:33
Callisto, Europa, around Jupiter, perhaps
9:36
Titan as well, they,
9:39
they could do use
9:42
this technology to
9:46
actually interpret what's going on
9:48
inside these worlds without having to land
9:51
a spacecraft on the surface. That's the,
9:54
the great thing because putting something
9:56
into orbit around Enceladus for example,
9:59
would be much more straightforward, much
10:01
less energy hungry than putting a
10:04
spacecraft down onto the surface where you've
10:07
got all the risks of collisions and tipping
10:09
over like several of the lunar probes have
10:12
done, they've fallen over. all of that is
10:15
the hazard when you're landing something on
10:17
the surface. So yeah, I think it's got a
10:20
future. Now. you can, as
10:23
I kind of mentioned earlier, you can do some
10:26
of this kind of work with a single
10:28
spacecraft, but if you can launch two with
10:30
this microwave, microwave bridge between
10:33
them, then you can do much, much more as the
10:36
Grail spacecraft demonstrated.
10:38
Andrew Dunkley: Okay, so yeah, the moon is not as
10:41
it seems, at least not on the inside.
10:45
Professor Fred Watson: Well no, that's right. Or maybe, maybe it is
10:47
as it seems because the two sides are so
10:50
different when you look at them. As you said,
10:53
the topography is quite different from one
10:55
side to the other.
10:56
Andrew Dunkley: It's a great story. If you'd like to read up
10:58
on that, you can find, you can go find the
11:00
paper if you can remember the title of it
11:02
because it's got more than three words in it.
11:04
So I'm stuffed. But yeah,
11:06
DailyGalaxy.com is the website.
11:09
DailyGalaxy.com this is
11:11
space Nuts with Andrew Dunkley and Professor
11:14
Fred Watson Watson.
11:18
Three, two, one.
11:21
Professor Fred Watson: Space Nuts.
11:22
Andrew Dunkley: Fred Watson, I neglected to mention my office
11:25
background at the beginning. if I just put my
11:28
thumb over the camera, people on YouTube will
11:31
see a massive mountain there. That's the Fugo
11:34
volcano in Guatemala. I took that photo on
11:36
the 7th of April. And Judy and
11:39
I have a history of visiting volcanoes,
11:41
getting home and then finding out they
11:43
started erupting. And that's exactly what's
11:45
happened with Fugo. So if you're on YouTube
11:47
and you're watching us, when we're finished,
11:49
go and have a look at some of the eruption
11:52
footage from the Fugo volcano in Guatemala at
11:54
the moment. It is spectacular. We had to
11:57
drive between three volcanoes to
12:00
get to the township of Antigua
12:03
and you could see these things for
12:05
miles. I mean they're strata volcanoes, they
12:08
are absolutely enormous. They're
12:10
around 12, 13,000ft at the peak
12:13
above sea level. and they
12:16
are spectacular. And we literally had to
12:19
drive between two of them to get to the town.
12:21
That one was on our left and the
12:24
agua volcano was on our right. and
12:27
the town is in the foothills of the the two
12:29
nearest volcanoes. And it's just an
12:32
awe inspiring sight. But I just thought it
12:35
was funny that well maybe not funny haha, but
12:37
funny that we went to Hawaii, got home
12:40
and Kilauea erupted. Happens a lot.
12:43
I went to Vanuatu, Matt Yasser, got home, it
12:46
erupted and stopped air traffic for a couple
12:48
of weeks. And now this one's erupting a month
12:51
after we were there. So we're not going to be
12:53
invited back I don't think. But
12:56
Fugo's got a history though it erupts quite
12:58
often. But I just thought people would be
13:00
interested to see a photo of it. as you know,
13:03
I'm a volcano junkie.
13:05
Professor Fred Watson: So when we were in Iceland earlier in the
13:07
year, the Reykjanes peninsula had
13:10
just erupted as well. Well here there was
13:13
a lot of steam coming up from from the, you
13:15
know, the fishes in the ground.
13:17
Andrew Dunkley: Yeah. In the next few months we'll be
13:19
visiting the Canary Islands.
13:22
Professor Fred Watson: Sure.
13:23
Andrew Dunkley: Yeah. So that one's got an active volcano
13:26
and we're visiting Iceland as well.
13:28
yeah. Could, could have some stories to tell.
13:31
Professor Fred Watson: Yeah.
13:32
Andrew Dunkley: Ah, good. Okay Fred Watson, let's move on
13:34
to our next story.
13:35
And this one is about yet again,
13:39
the Hubble tension, the, the
13:42
quirk of space that we
13:45
can't quite get our heads around. We can't
13:47
solve the differentials or the problems. Many
13:50
are saying, look, it's natural. But
13:53
Now another Hubble
13:55
Tension theory, gee that's hard to say.
13:59
is making its way into various papers. one in
14:01
particular I suspect, because now they're
14:04
talking about evolution
14:07
in dark matter. This sounds
14:09
like pie in the sky type stuff but
14:12
we've got to, we've got to come up with
14:14
answers. The only way it is to publish papers
14:17
with theories and you know,
14:20
toss it around.
14:22
Professor Fred Watson: Indeed.
14:22
Andrew Dunkley: That's like, like a salad. A space
14:25
salad.
14:28
Professor Fred Watson: yeah, I've just I'm m hesitating because I've
14:30
just seen who one of the authors of this
14:32
paper is.
14:35
it's a scientist who's known for
14:38
provocative papers. Avi
14:41
Loeb, and he's at Harvard, Smithsonian,
14:44
Centre for Astrophysics. So the
14:47
paper that we're talking about is called
14:48
Evolving Dark Energy or Evolving Dark
14:51
Matter. and
14:54
this is really esoteric stuff, Andrew.
14:57
Always when we're talking about this stuff
15:00
we're just glossing over
15:03
a lot of really detailed
15:06
science that goes into
15:09
realms that even I struggle with. And I'm not
15:11
actually a cosmologist, which is why. But
15:14
I'm supposed to know my way around some of
15:16
these topics better than perhaps
15:19
the person in the street is.
15:22
and this
15:25
comes down to something called the equation
15:26
of states which you and I haven't talked
15:28
about. But the equation of state is a
15:31
parameter in the universe. It's a parameter
15:34
generally. It comes from thermodynamics,
15:37
which essentially characterises,
15:41
as the name almost implies, it
15:43
characterises the overall behaviour of the
15:46
universe. The equation of states, okay,
15:48
Symbolised by the, the character W.
15:53
so the, the work that's
15:55
being reported here. and as I've said
15:58
it's on a, on a, there's a, there's a.
16:02
Basically a preprint as we used
16:05
to call them. this is a paper that's not yet
16:07
been refereed which is
16:11
going to go into. I can't see
16:14
what journal it's aiming for but it
16:17
is called
16:20
essentially the title of the paper Evolving
16:22
Dark Energy or Evolving Dark Matter. I'm
16:24
going to read you the abstract, okay?
16:27
because that kind of tells the story even
16:30
if you don't know what the details are.
16:33
We show that the latest
16:36
empirical constraints on cosmology, and by
16:39
that they mean measured, from a Combination
16:42
of desi, that's the Dark Energy Survey
16:44
instrument cmb, that's the cosmic
16:47
microwave background and supernova data,
16:49
that's exploding stars. They've taken all
16:52
this data together. The empirical
16:55
constraints on cosmology from that
16:56
combination can be accounted for. If
16:59
a small component of dark matter
17:03
has an evolving and oscillating
17:06
equation of state within the range minus
17:09
1 is greater than less than w, which is
17:12
less than 1, that's the range minus 1 to 1 is
17:15
somewhere where this equation of state
17:17
parameter, W lies. From a fundamental
17:20
physics perspective, this interpretation is
17:22
more appealing than an evolving
17:24
phantom dark energy with W less
17:27
than minus 1, which violates the null
17:30
energy condition. So
17:33
in a sense this paper is kind of in
17:36
response to what we're seeing from the
17:39
latest data actually from desi, the Dark
17:42
Energy Survey, which
17:44
suggests that dark energy
17:47
is getting less. Or at least what it
17:50
suggests is the acceleration of the
17:52
universe's expansion is getting less.
17:55
In other words, the expansion which we know
17:57
is accelerating because that's been well
17:59
measured. But the suggestion is that that
18:02
acceleration is slowing down, so
18:05
as time goes on it will be accelerating at a
18:08
lower rate. What they're saying is,
18:11
when you look at the sort of theory that
18:14
doesn't make sense, but it makes more sense
18:17
if something is going on with
18:19
dark matter, that dark matter,
18:23
is itself evolving. Now
18:26
that suggests, and they apparently
18:29
explore this in the paper, I haven't read the
18:31
paper, but they explore this, that suggests
18:34
that dark matter is something different from
18:37
what we think it is because we imagine dark
18:39
matter as being some subatomic particle,
18:43
which is as yet unknown, which does not
18:45
interact with normal matter at all, which is
18:47
why we can't see it, and all it
18:50
reveals itself by is its gravity. That's
18:53
the parameters that we understand dark matter
18:55
to be. But what they're
18:57
suggesting is that this is
19:00
something even more exotic than we have been
19:03
imagining, because
19:06
its parameters change, its
19:09
phenomena change and that leads to a
19:11
changed equation of state, the
19:14
W parameter.
19:18
And they actually suggest,
19:22
that actually there's some sort of
19:24
oscillation going on in it as well. Not just
19:26
dark matter. There's a very nice article on
19:29
physics phys.org
19:32
by Brian Koberlein. I'm going to read
19:35
a paragraph for it.
19:39
in fact I'm going to read a couple,
19:42
let me just read from this because I think
19:44
that's going to explain it better than me
19:46
waffling on. In work published on the
19:49
Arxivist print server, the Authors look at
19:51
both evolving dark energy and evolving dark
19:53
matter and argue that the latter is a much
19:56
better fit to the observational data. The
19:58
first thing they know is that the two models
20:00
are somewhat related. Since the evolution of
20:03
the cosmos depends in part on the ratio of
20:05
dark energy to matter density, a model
20:08
with constant dark matter, which is what we
20:10
have at the moment, and evolving dark energy,
20:13
will always appear similar to a model with
20:16
evolving dark matter and a constant dark
20:19
energy. That's a good point. They then go on
20:21
to explore the idea of some kind of exotic
20:23
dark matter, one that has a changeable
20:25
equation of state to match observation. The
20:28
dark matter equation of state must
20:30
oscillate in time. This isn't an
20:33
outlandish notion. I think
20:36
they're trying to convince us here in
20:38
space.org neutrinos have mass
20:41
and don't interact strongly with light. While
20:43
they can't account for all the dark matter in
20:45
the universe, they are a form of hot dark
20:47
matter. And neutrinos undergo, mass
20:50
oscillation. Perhaps cold and dark
20:53
matter particles undergo, Sorry. Perhaps cold
20:55
dark matter particles undergo a similar
20:59
oscillatory, effect. The authors find
21:02
that the best fit to observational data is a
21:05
universe where about 15% of the cold dark
21:07
matter is oscillatory, and the
21:10
remaining 85% is standard dark
21:12
matter. This would allow for the Hubble
21:15
tension to be covered while still matching
21:18
the dark matter observations we have.
21:21
And I love the last paragraph.
21:23
Andrew Dunkley: Yeah, I do too. I was just reading it.
21:25
Professor Fred Watson: It should be stressed that this work presents
21:28
a toy model. As the authors themselves note,
21:31
the work is a broad concept that does not pin
21:33
down specific constraints for dark matter
21:34
particles. But the work does open the door to
21:36
a broader range of dark matter models. At
21:39
this point, evolving dark matter is worth
21:41
considering. Well, I agree with that. I think
21:43
everything's worth calling.
21:44
Andrew Dunkley: I was going to ask you where you stand on
21:46
this and if it's worth considering, then
21:48
obviously it is. But it
21:51
just adds another potential
21:54
explanation of something we know very little
21:57
about and.
21:59
Professor Fred Watson: Yep. And we worry about a lot, especially
22:02
on space. Nuts.
22:03
Andrew Dunkley: Yes, yes. And we get a lot of questions about
22:05
it. And so a lot of people thinking about
22:08
this stuff, if it's, if it's in fact
22:10
stuff.
22:11
Professor Fred Watson: Yes, well, yes, that's right. It could be
22:13
something other than stuff.
22:14
Andrew Dunkley: Yes, yes. So, yeah, it's a
22:17
really interesting idea and, well, I
22:20
suppose, it'll get tossed around and people
22:22
will come up with other explanations. But the
22:24
thing is, a paper like this, even if it's
22:27
wrong may spawn a level of thinking
22:30
that might send us down a path where we might
22:32
eventually figure it out. I mean that's
22:34
another possibility.
22:36
Professor Fred Watson: that's, that's true. That's correct.
22:39
and that's the way science works as well.
22:41
Exactly as you've said.
22:42
Yes, indeed.
22:43
Andrew Dunkley: All right. as Fred Watson said, you can
22:45
read all about it@the phys.org website.
22:48
That's P-Y-S.org or you
22:51
can read the published paper on the archive
22:54
reprint server if you like. This is Space
22:56
Nuts. Andrew Dunkley here, Fred Watson Watson
22:59
there.
23:01
Okay, we checked all four systems.
23:06
Our final topic today, Fred Watson,
23:08
is a really interesting one and it
23:11
is going to take us to the Kuiper
23:14
Belt.
23:14
So tighten up your buckle and get ready for
23:17
this one because we think there has
23:20
been discovered a triple system in the Kuiper
23:23
Belt. Now when we talk about the Kuiper
23:26
Belt we don't really, we've only been there a
23:29
couple of times. fairly recent missions in
23:32
the last decade or so. But we've only had
23:35
close up observations of two objects
23:38
in the Kuiper Belt. So
23:41
this discovery was actually made not by
23:43
either of those probes but, or the
23:46
probe in question. it was made from
23:49
Earth, am I correct?
23:51
Professor Fred Watson: Yes, that's right. using the Hubble
23:54
Space Telescope.
23:55
Andrew Dunkley: Yeah.
23:57
Professor Fred Watson: Which is you know, still going strong
23:59
and still a
24:02
fantastic resource
24:05
given that it's now 35 years
24:08
in space. Yes, it is amazing. That's
24:10
right. so, and again this is a
24:13
team of researchers from NASA. what they've
24:16
been doing is looking through ah, Hubble
24:18
telescope data at this very distant
24:22
object which is it's
24:24
a, an asteroid. So it's got a number
24:26
148780 and
24:29
it's known as Algeria. that's its name.
24:33
and they, they,
24:36
they haven't seen the three
24:39
bodies that they now think make it up, but
24:41
they've seen two.
24:42
Andrew Dunkley: Wait, dad, joke coming.
24:44
Professor Fred Watson: Oh good. Okay. They're seeing two of them.
24:47
Andrew Dunkley: I was going so they haven't seen the three
24:48
bodies. That's a problem.
24:50
Professor Fred Watson: Oh, there we go. Love it. Love
24:53
it. I
24:56
don't understand. You must rehearse our
24:58
conversations weeks in advance, Andrew, to
25:00
get.
25:00
Andrew Dunkley: No, the scary part is this
25:03
garbage just pops in there
25:06
at random moments. It used to happen
25:09
when I was on the radio. I'd just be talking
25:11
about something and a little voice ago,
25:14
hey, tell this joke.
25:15
Professor Fred Watson: Yeah. And then at the end of it you think I
25:17
got a Wish I hadn't said that.
25:20
Yes, yeah.
25:21
Andrew Dunkley: Ah, yeah, yeah.
25:22
Professor Fred Watson: Anyway, so it's, it,
25:25
it basically is new, ah, research.
25:28
And so, so they can see two. They can
25:31
detect that there are two objects
25:34
orbiting one another.
25:35
Andrew Dunkley: I sent the but.
25:37
Professor Fred Watson: The butt is. Yes, yes. the
25:40
but is that it looks as though one of them is
25:43
actually a pair of objects. That's the trick.
25:46
So we've got two things that have been
25:49
seen, but one of them is
25:51
probably a double. And they've had to
25:54
use the very detailed,
25:58
measurements of the way
26:00
the object that they can see orbits the other
26:03
one, the way that orbit changes.
26:06
that is what tells you that the
26:09
central object, if I can put it that way,
26:11
might actually be two. and so it's
26:14
the outer object, its orbit
26:17
changes over time. And it's that change,
26:20
that allows the deduction that the central
26:24
object, if I put it that way, is.
26:28
Well, they say it's either extremely
26:31
elongated or it's two separate objects.
26:34
And that, you know, the odds are that it is
26:36
actually probably two. often though,
26:39
we've got this situation, especially with
26:42
these distant, asteroids,
26:46
where you have clearly something that
26:48
has been a binary, two objects in orbit
26:51
around one another, but they've gradually,
26:54
collapsed together, not in a violent way,
26:57
and wound up in contact, which is something
26:59
we call, believe it or not, a contact binary.
27:02
And Arrokoth, it's one of the Kuiper Belt
27:05
objects that you actually just referred to.
27:08
It's beyond the orbit of Pluto. It was
27:09
visited by New Horizons. when we saw it, it
27:12
looked like a snowman. And that was very
27:14
seasonal because I think it was Christmas
27:16
time, when it was discovered. But the
27:18
analysis of, New Horizons data as it
27:21
flew past Arrokoth showed that it wasn't
27:24
actually two balls joined together. It was
27:25
two pancakes joined together, rim to rim,
27:29
so that it actually looked like a snowman,
27:30
but from the edge on, it looked a lot more
27:32
like two pancakes stuck together. But that's
27:35
a common phenomenon. Two objects, whatever
27:37
their shape, is coming together gently and
27:40
actually, basically cementing
27:43
themselves together just by gravity. But then
27:45
the sort of gap between them fills in and you
27:47
end up with something that looks like a
27:49
peanut. So I think it's still possible
27:53
that Algeria could have that sort
27:56
of shape. But they actually say,
27:59
the research team who's done this, they say
28:02
that the triple system actually fits the data
28:05
best. it fits it better
28:08
than a contact binary or a really elongated
28:11
central object. So a triple system is what we
28:14
Believe it is, it's a very nice target for
28:17
a future mission to the outer solar system,
28:19
but that's not going to happen anytime soon.
28:22
but, yeah, so, very nice discovery. Triple
28:24
systems are rare. That's why, that's why it,
28:27
you know, it's making the headlines. These
28:29
are rare phenomena. Binaries are very common.
28:32
In fact, probably most objects out there in
28:35
this outer solar system might be binaries,
28:37
but triple systems are rare.
28:39
Andrew Dunkley: interestingly, this, rock, if you want to
28:42
call it that, or system Algeria,
28:45
is much, much bigger than Arrokoth. it's,
28:47
about 124 miles wide, or 200
28:50
kilometres. That's a big chunk.
28:53
Professor Fred Watson: Yes, it is, yes. A lot, more substantial than
28:55
Arrokoth, which was only, if I remember
28:57
right, it was less than a kilometre, I think.
28:59
it's amazing that they found it at all. To
29:02
give New Horizons a target beyond, Pluto.
29:06
Andrew Dunkley: Yeah, yeah, as you say, we're probably not
29:08
going to go back out there in a hurry. These
29:10
missions are very long winded
29:13
because of the distances involved. We're
29:15
talking what, 30 or 30
29:18
AU or something?
29:20
Professor Fred Watson: Yeah, I think this is more, I think it's more
29:21
like 45 AU or something like that. So it's.
29:24
Yeah, AU is an astronomical unit,
29:27
150 million kilometres.
29:29
Andrew Dunkley: Yeah, that's a long way away. but
29:32
yeah, it's probably an area of our
29:35
solar system, even though it's so remote,
29:37
that we need to learn more about because, you
29:40
know, some of these rocks get
29:43
bumped and end up heading our way.
29:45
Professor Fred Watson: yes, that's right, they do, or, you know,
29:48
gravitationally interact with other objects.
29:50
but you're right, in some
29:53
ways it's the last frontier. It's completing
29:56
the evidence for the way we think. Our
29:58
solar system formed by this icy,
30:01
dust and gas cloud that collapsed. And a
30:04
lot of this stuff is the last vestiges, the
30:07
outer, the outer vestiges of those,
30:10
you know, those, objects that eventually went
30:12
up to make the inner planets. These are,
30:14
these are worlds that have never been heated.
30:16
And that's the, you know, the planets have
30:19
been, they've been bombarded by gravitational
30:22
interactions by collisions and, impacts
30:25
and things of that sort, so that they're hot.
30:27
these worlds have always been cold and that's
30:30
why they're so interesting, because they're
30:32
sort of the fossil of the solar system's
30:34
earliest history.
30:35
Andrew Dunkley: Yeah. Yeah.
30:36
Well, I guess the time will come where we do
30:37
extensive studies, but, I think we'll have to
30:39
get better spacecraft and maybe use
30:42
those, superhighways you were talking about.
30:45
Professor Fred Watson: Yeah, yeah, that's right.
30:46
Andrew Dunkley: Get out there and have a look.
30:48
Professor Fred Watson: Yes.
30:48
Andrew Dunkley: if you'd like to read up on that, you can do
30:50
that at the NASA science website or you can
30:53
go, to the study itself, which was published
30:55
in the Planetary Science Journal.
30:58
that brings us to the end. Fred, thank you so
31:01
much.
31:02
Professor Fred Watson: it's a pleasure, Andrew. a nice surprise to
31:04
see you and, always a pleasure to talk.
31:07
Andrew Dunkley: Good to see you too. And we'll catch you on
31:09
the very next episode. Don't forget to visit
31:11
us online. In the meantime, we've got, plenty
31:13
of platforms. We're on Instagram, we're on
31:15
YouTube, we're on Facebook, we're on our
31:18
own website, spacenutspodcast.com
31:20
SpaceNuts IO Either URL will
31:23
take you to the same place and have a look
31:25
around while you're there. And, Huw
31:28
in the studio, he did actually turn up
31:30
briefly today, but he forgot to put on his
31:33
kuiper belt and his pants fell down, so he
31:35
had to make a run for it from me,
31:38
Andrew Dunkley. Oh, it's terrible. Thanks,
31:40
for your company. We'll see you on the next
31:42
episode of Space Nuts.
31:43
Professor Fred Watson: Bye. Bye.
31:45
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