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Cosmic Questions, Red Dwarfs & the Search for Life Beyond Earth · Space Nuts: Astronomy Insights & Cosmic Discoveries

0:00
Heidi Campo: Welcome back to another Q and A session of
0:03
Space Nuts. I'm your host for this
0:06
American summer, an Australian winter,
0:08
Heidi Campo. And joining us today to
0:11
answer all of your questions is Professor
0:13
Fred Watson, astronomer at large.
0:16
Generic: 15 seconds. Guidance is internal.
0:19
10, 9. Ignition
0:21
sequence start. Space nets 5, 4,
0:24
3, 2, 1. 2, 3, 4, 5, 5,
0:27
4, 3, 2', 1. Space nuts
0:30
astronauts report it feels.
0:33
Heidi Campo: Fred, how are you doing?
0:34
Professor Fred Watson: Oh, pretty well, thanks Heidi. Nearly as well
0:37
as I was the last time I saw you.
0:42
Heidi Campo: Oh, inside jokes. For those of you regular
0:44
listeners, you know what's going on.
0:46
Professor Fred Watson: Yeah. Because you were
0:49
a bit under the weather before.
0:50
Heidi Campo: I, I am. So if you guys hear my voice sounds
0:53
a little bit scratchy, I apologize. I was
0:55
doing some traveling recently and I was
0:58
probably picked up a little germ at the
1:00
airport. But that's I, I, I'll be okay. I
1:03
think I'll survive this time.
1:05
Professor Fred Watson: Hopefully.
1:06
Heidi Campo: Hopefully. Yeah, I don't know. I guess you
1:08
never know. Could be, could be.
1:11
didn't like you think about those crazy cases
1:13
where it's like didn't Bob, Bob Marley died
1:15
from skin cancer and it's like, I guess you
1:17
really never know.
1:19
Professor Fred Watson: That's true.
1:21
Heidi Campo: Well, hey, here's something that hopefully
1:23
you can answer for us, Fred.
1:26
Rennie from S.A. sunny West
1:28
Hills, CA asks
1:31
theoretically, if an observer
1:33
scientist outside our universe was able to
1:36
look into our universe, would that
1:39
observers re research on light
1:42
speed and other phenomenon match our
1:45
scientists findings?
1:49
Professor Fred Watson: It's a great question, Rennie. Rennie's one
1:52
of our regular questioners and always asks
1:55
the provocative ones. I like it very much
1:59
so.
2:02
Professor Fred Watson: We'Ve got to envisage an observer that's in
2:05
some other universe where the light
2:08
speed and other, you know, other
2:12
fundamental quantities, speed
2:15
of light, mass of the electron, things like
2:16
that, they might be quite different.
2:19
so you would have to
2:22
basically think outside the box.
2:25
We're talking now about the biggest boxes
2:27
that could exist. If we're talking about
2:29
separate universes, you'd have to
2:32
look into our universe and use yardsticks
2:34
that were basically part and
2:37
parcel of our universe in order to measure
2:40
those fundamental quantities. So
2:43
you'd need to have a way of determining
2:45
distance, and that way you could
2:48
perhaps use a way of determining time
2:52
to determine the speed of light. you might
2:54
well be able to determine that the speed of
2:57
light in our universe was different from the
2:59
speed of light in your universe, which will
3:00
be a very interesting property. and
3:03
it's actually one of the reasons why People
3:06
speculate, Heidi, that, there might be other
3:08
universes. The fact that those physical
3:11
parameters in our own universe are
3:13
so well suited to, the
3:16
formation of stars, galaxies,
3:19
planets, stability that,
3:22
would allow molecules to be created that
3:25
could eventually turn into living organisms.
3:28
One of the reasons astronomers think there
3:30
might be other universes is because those
3:33
properties of our own universe are so well
3:35
tuned to life that maybe there are other
3:37
universes where that is not the case. And
3:40
so if you were standing in one of those
3:42
universes and looking back at our own, you
3:44
might well say, well, that's ridiculous. The
3:47
speed of light, there's only 300,000
3:48
kilometers per second. It's much faster than
3:51
that here. So, you know, you could be looking
3:53
at different parameters. So I think, Rennie,
3:55
it's an interesting thought experiment and,
3:58
thank you very much for the question.
4:01
Heidi Campo: It's very, interstellar when he goes into the
4:04
dimension where they're looking through a
4:06
different plane.
4:08
Our next question is from Dean, and
4:10
Dean says, I believe you all
4:13
had mentioned previously that in a,
4:15
protoplanetary disk, heavier
4:18
elements reside closer to the star,
4:21
which is the reason the interior planets of
4:24
our system are, quote, rocky.
4:27
The protostar is too hot for
4:29
volatile materials to become solid,
4:32
and the solar wind blows the lighter elements
4:34
away. My question
4:38
was Earth in a belt of protoplanetary
4:41
disk where liquid or water orbited?
4:44
Could such a belt exist in protoplanetary
4:47
disk?
4:49
Professor Fred Watson: yeah. It is another great
4:52
question. And I suppose what Dean is
4:55
saying is, is there
4:58
a Goldilocks zone in the protoplanetary disk?
5:01
because the protoplanetary disk is
5:04
where the planets were formed. and
5:07
yes, the temperature of material in that disk
5:10
will vary. It'll be much hotter near the star
5:12
itself and much colder outside. And
5:16
we do see, just in the way the
5:19
planets of our solar system are distributed,
5:21
with the four rocky ones internally and then
5:24
the four, gaseous ones and icy
5:27
ones further out, we see that
5:30
effect of, the
5:32
Goldilocks zone. So Mars sits
5:35
just within the sun's ice.
5:38
what's it called? The ice limit?
5:42
Can't remember. Anyway, it's something like
5:44
that. It's where, water ceases to be
5:47
a vapor and becomes ice.
5:51
so beyond the orbit of Mars,
5:54
things, things basically freeze.
5:57
if, if, if you've got water vapor. and
6:00
that is thought to be why the gas giants
6:03
grew so big, the four gas giants,
6:06
because, the fact that their water is
6:09
actually the commonest two element molecule
6:11
in the whole universe. so if the
6:13
water vapor becomes something solid,
6:16
beyond that that ice limit, then,
6:19
then you're going to get the
6:21
collection of much more mass
6:25
in a planet that's being built by this
6:27
process of accretion. so because
6:30
the water is now in a solid form, you can
6:32
build a much bigger planetary core.
6:35
and that is why you can then get something
6:38
big enough that it actually hangs onto the
6:40
gases surrounding it and you've got a gas
6:42
giant. So that's the picture that we imagine
6:45
is the way planets form.
6:48
So just turning
6:51
to Dean's question. Was Earth in a belt of
6:54
the protoplanetary disk where liquid water
6:56
orbited? it wouldn't have been liquid because
6:59
you can't have liquid in a
7:02
vacuum. but you can get water
7:04
molecules in vapor form
7:07
basically or in the form of ice.
7:10
And yes, there would have been a step there I
7:12
think in the protoplanetary disk where the
7:15
ice solidified, where you've got solid ice.
7:18
so I think that's a really good question and
7:21
I believe I've seen
7:24
some papers recently, which
7:27
suggest that we are actually observing that
7:30
in fact, very recently, I think it might even
7:32
have been last week, Heidi, there was a paper
7:34
that reported the detection of
7:37
ice in a protoplanetary disk.
7:40
so that's one to check out. it's
7:43
yeah, it's there and in the inner regions
7:45
it's probably too warm for it to exist as
7:48
a solid material.
7:50
Heidi Campo: So Dean's, Dean's onto something. We get a
7:53
lot of really smart people who follow along
7:55
this show too.
7:58
Andrew Dunkley: Let's take a break from the show to tell you
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Now back to the show.
9:27
Generic: Three, two, one.
9:30
Space Nuts.
9:32
Heidi Campo: Our next question comes from Ron. And he
9:34
says hello from upstate New York. Ron. That
9:37
is where my husband is from. I wonder if
9:39
you're from the Catskills area. Beautiful
9:41
place, if any of you guys ever get to visit.
9:44
Generic: Hello.
9:45
Heidi Campo: Ron says hello from upstate New York. I was
9:47
wondering, with the extreme lifetime of red
9:50
dwarf stars being one of the
9:53
order of trillions of years, could there be
9:56
any population of, I think that says
9:59
of population three. Sorry, Population
10:01
three red dwarf stars. Maybe I should ask
10:04
first, do we think red dwarf stars were
10:06
formed right after the Big Bang to be a part
10:09
of the population 3 stars? Thank you for
10:12
considering my question and always
10:15
informative podcast from Ron.
10:18
Professor Fred Watson: Thanks, Ron. and greetings to upstate New
10:21
York. yeah, that's another.
10:24
They're all great questions that we count
10:26
space nuts. and it's a
10:29
very intelligent one as well. And just to
10:31
sort of give the backstory of this Population
10:33
three stars, and it's usually written as a
10:36
Roman three stars.
10:39
They're what we think of as being the first
10:41
stars to form in the universe
10:44
back probably within the first 2 or
10:47
300 million years of the Big Bang,
10:49
which we believe happened 13.8 billion years
10:52
ago. so we. What
10:55
would signify a population three star? It
10:58
would be a star, whose spectrum,
11:01
when you analyze its light, reveals
11:03
only the presence of hydrogen and helium,
11:06
because they were the elements that were
11:08
predominantly produced in the Big Bang. There
11:10
were a few other things produced in very,
11:12
very small quantities,
11:15
like lithium, but really it was
11:17
mostly hydrogen and helium that were produced
11:19
in the Big Bang. And so population
11:22
3 stars will be stars that only show
11:25
the signatures of those chemical
11:28
elements in their spectrum. We haven't
11:31
actually found any yet. We found some that
11:33
look very nearly like Population 3 stars, but
11:36
they still have a little trace of iron in
11:37
them, the ones that have been found, and iron
11:39
is formed, in the interior of
11:42
stars. And so you know that anything that
11:44
shows up iron is not the first generation of
11:47
stars ever to exist because other stars have
11:50
been there first, and have formed the iron.
11:53
So population three stars are a bit of a holy
11:55
grail, actually. Trying to find Them, I've
11:58
worked with, people here in Australia
12:00
whose sole scientific mission has been to
12:03
find population, three stars. And they've
12:04
come pretty near it with these very early,
12:07
what we call metal pore stars. Metals,
12:10
unlike the way we think of metals in everyday
12:12
life, things that
12:15
contribute steel and brass and stuff like
12:17
that, metals are anything other than hydrogen
12:19
and helium. To an astronomer it's a very
12:21
curious expression. so metal poor stars are
12:24
ones that don't have much of anything other
12:26
than hydrogen, helium. So the
12:29
cutting to the nub of Ron's question though,
12:33
we think the very first generations of stars
12:36
to form in the universe
12:39
were not, were not red
12:41
dwarfs. we don't think they were dwarf stars
12:43
at all. We think they were
12:46
very massive stars, perhaps 20,
12:49
maybe even up to 100 times the mass of the
12:51
sun, that had very short lives, and
12:54
exploded, you know, within perhaps less than
12:57
a million years. Such a short life that,
13:00
remember our sun is four, and a half
13:03
billion years old and it's in its sort of
13:05
middle age, midlife, not a crisis, but a
13:08
midlife term. So red dwarfs
13:11
probably did not form in the early universe.
13:14
And in any case, what categorizes a
13:17
red dwarf star, is actually the
13:20
fact that it has
13:23
seen many generations of stars before it
13:26
because they're rich in all
13:28
kinds of different chemical elements, not
13:30
just hydrogen and helium. they are
13:33
basically, you know, cool
13:36
stars, which show the characteristic
13:39
signatures of all sorts of things, even
13:41
molecules. I think some molecules. Molecules
13:44
don't usually exist in stars because they get
13:46
torn apart. The atoms get torn apart by the
13:48
heat. But I think red dwarf stars have some
13:50
molecular signatures as well. so the answer
13:53
is, I think no. red dwarf stars weren't
13:56
formed right after the Big Bang. And there
13:59
probably aren't any population three red
14:01
dwarf stars. But you're absolutely right that
14:03
the lifetime of red dwarf stars is very, very
14:05
long. Maybe, up to trillions of years as
14:07
you've suggested. Ron, thanks very much for
14:09
the question.
14:11
Heidi Campo: Very interesting, very interesting indeed.
14:16
Andrew Dunkley: Okay, we checked all four systems.
14:19
Professor Fred Watson: Space nets.
14:20
Heidi Campo: Our very last question is another
14:24
great question from Jake Johnston.
14:27
He says. Hey, space nuts, quick question.
14:30
While it is totally possible that there is no
14:33
life in our solar system except for on Earth,
14:36
if you had to guess where the most
14:38
likely other place in our solar system is
14:41
to find either current or ancient life,
14:45
what would you choose? Titan. Mars.
14:48
Thanks.
14:52
Professor Fred Watson: let's give you a shot at this one, Heidi.
14:53
What do you think the answer to that would
14:55
be?
14:55
Heidi Campo: Oh, you know, I was actually thinking in my
14:57
head of playing a joke and just saying some
14:59
random planet and then going, oh, oops, he
15:02
must have meant this for you. I
15:05
don't know. I really think that
15:08
it's gonna, for some
15:11
reason I think there's probably something on
15:13
a moon somewhere because
15:17
I'm just imagining
15:19
primordial solar system, everything's
15:22
crashing into each other and when
15:25
it, when that matter ends up on a
15:28
planet it's getting churned through its
15:30
core and getting heated up and everything
15:33
that maybe existed, even bacteria, is just
15:35
getting cooked and destroyed. But on a moon
15:38
it's not getting that turnover. So I would
15:41
assume, and this is with my background
15:44
not in this at all, I would assume that we
15:46
would find something on a moon.
15:48
Professor Fred Watson: I think you're right actually. so I
15:51
guess the most obvious
15:54
places to look, first of all Mars,
15:57
Mars we know has been warm and wet
15:59
in the past. we know that it was warm and wet
16:02
at a time when the first living organisms
16:04
were forming on Earth. So if all you need is
16:07
the right atmospheric conditions while they
16:09
were there on Mars. And so Mars
16:12
may show signs of ancient microbial life.
16:15
Unfortunately we don't at the moment have the
16:16
wherewithal to find it. We've got samples
16:20
of rocks and soil that have been taken by the
16:23
Perseverance rover on Mars which are stashed
16:25
away for a future mission to go and collect
16:27
them. Sadly that mission is a bit in
16:30
doubt at the moment because it's turned out
16:32
to be very expensive. but there may be
16:34
evidence on Mars. but you're
16:37
absolutely right that some of the moons of
16:39
the solar system are perhaps the next on the
16:42
list because first of all, and
16:45
this is the one that's really the poster
16:47
child of looking for life on moons in the
16:49
solar system is Europa. Europa, one
16:52
of Jupiter's moons, which we know has
16:55
a rocky core, it's got a liquid water ocean
16:57
over that core, and that is sealed in
17:00
by a layer of solid ice on top of it.
17:03
And we have seen evidence of geysers
17:05
of ice, crystals coming
17:08
through that
17:11
layer of ice because of cracks in it.
17:14
there is evidence as well that there are
17:17
quite complex carbon containing molecules,
17:21
on the surface of Europa got a
17:24
reddish brown colour which looks as though
17:26
it's the effect of sunlight
17:29
and solar radiation on these carbon
17:31
containing molecules. So the ingredients for
17:34
life might very well be there. likewise,
17:37
further out in the solar system, Enceladus,
17:40
Saturn's moon which was explored by Cassini,
17:43
that definitely has these geysers of ice
17:45
crystals because we've seen them and in fact
17:47
Cassini flew through them and measured some
17:49
of the contents, of them. in terms
17:52
of it's mostly water ice, but there's also
17:54
molecular hydrogen and some other really
17:56
interesting ingredients that suggest that
17:58
there are geothermal vents down at the bottom
18:01
of Enceladus oceans. Maybe that
18:03
is where life could have kicked off. We think
18:06
life might have kicked off on Earth down in
18:08
hydrothermal vents, maybe on Enceladus too.
18:12
And you know, Dean mentions also Titan.
18:15
I, beg your pardon, Jake. I'm sorry, Jake,
18:18
the wrong name there. Jake also mentions
18:20
Titan, which is another of these ice
18:23
worlds with the same sort of structure and a
18:25
liquid ocean, but it's also got these lakes
18:27
of methane and ethane, natural liquefied
18:30
natural gas. The only place we
18:33
know anywhere in the universe other than
18:35
Earth where there's liquid in equilibrium
18:38
with an atmosphere. And Titan has a thick
18:41
atmosphere, mostly carbon dioxide, but
18:43
hydrocarbons in there as well. So these are
18:46
all great candidates for living organisms.
18:49
and if I had to pick one, let's go with
18:52
Titan because I think you get two shots at it
18:55
there. There might be water, based life in
18:58
the oceans underneath the surface, but there
18:59
might also be carbon, some weird carbon
19:02
based life in the liquid, natural
19:05
gas, lakes and seas on Titan. And we might
19:08
find that when the Dragonfly spacecraft
19:11
visits Titan later, in.
19:13
Heidi Campo: The decade, these are
19:16
all very exciting.
19:17
I mean there is just so much happening in
19:19
space right now. Every single week we are
19:22
closer and closer to new breakthroughs and
19:25
new discoveries. and I'll even share a
19:27
program that I'm a part of that anybody who
19:30
is a high school, or like if you're
19:33
in high school, if you're doing your
19:34
undergrad graduate or early career
19:36
professional, you can join this too. It's
19:39
called the L space, so l
19:41
apostrophe space program. And it is
19:44
a competitive proposal writing program
19:47
where they select different individuals.
19:49
So you can apply. I'm in the summer program
19:51
right now, but you can apply for the fall
19:53
program. But all of us got put into different
19:56
interdisciplinary teams and we are going to
19:58
be coming up with a proposal that is
20:01
going to address one of NASA's gaps. And they
20:04
have a whole training on how to write
20:07
proposals the way NASA wants them written and
20:09
the taxonomy of everything they're looking
20:11
for. And the gaps that need to get filled.
20:13
But the cool thing is, is that, the
20:16
proposals that we come up with, one, of them
20:19
will be selected as the winner. And the
20:21
winner will get thousands of dollars of grant
20:23
money and it will probably go on to become a
20:25
real project. So if you are
20:28
an engineer, even a high school or early
20:31
career professional or anyone in between who
20:34
feels like you have a lot of good ideas for
20:36
discovering these kinds of things, like I've
20:38
been co hosting now for a while and I've seen
20:41
how smart you guys are. So I would really
20:43
encourage you to all get involved and use
20:46
your, creativity to help push humanity
20:49
forward into the stars. Because every single
20:52
one of you has something to add. And never,
20:54
ever, ever let imposter syndrome get in the
20:56
way of that. Because every creative mind
20:59
add something to all of this. And that's my,
21:02
that's my rah rah for this week.
21:05
Professor Fred Watson: Remind us again what the program's called.
21:07
Heidi Campo: It's L Space. So it's an L
21:10
apostrophe and then S, P, A, C, E.
21:13
And the program that I'm in, they have
21:15
several different programs. So I'm in the,
21:17
proposal writing. So np, W, E,
21:20
E. NASA Proposal
21:23
writing Experience. Something, something,
21:25
something, something. It's. They love, they
21:28
love acronyms. They just.
21:31
They, But yeah, L, Space. and you can look
21:33
that up. I can probably send the link to that
21:36
to you guys to post, in the
21:39
link and the description of this episode if
21:41
anybody is interested in adding to
21:45
their contributions into space.
21:48
Professor Fred Watson: Fantastic. great program.
21:51
and I look forward to checking out on the
21:53
Web.
21:53
Heidi Campo: On the Web, absolutely. Well, thank you so
21:55
much, Fred. This has been another wonderful
21:58
Q A session of Space Nuts.
22:01
We'll catch you.
22:02
Professor Fred Watson: Thank you.
22:03
Heidi Campo: We'll catch you all next week. Bye for now.
22:07
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