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Space Questions: Gravity's Pull, Cosmic Debris & Habitability Zones · Space Nuts: Astronomy Insights & Cosmic Discoveries

0:00
Heidi Campo: Welcome back to another episode of space
0:02
nuts.
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Generic: 15 seconds. Guidance is internal.
0:06
10, 9. Ignition
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sequence start. Space nuts. 5, 4, 3,
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2. 1. 2, 3, 4, 5, 5, 4,
0:14
3, 2, 1. Space nuts. Astronauts
0:17
report. It feels good.
0:19
Heidi Campo: This will be a Q A episode where you, the
0:22
listeners, have written in your questions and
0:25
we will answer them for you.
0:27
I am your host, Heidi Campo, joining you
0:30
for possibly my last episode.
0:33
We don't know quite yet. Andrew might be back
0:36
next week, but if he's not, then
0:39
I'll be back and I will say goodbye again.
0:42
But until then, we still have, um, for now
0:45
and the foreseeable future, we have our
0:47
beloved professor Fred Watson, astronomer at
0:50
large. How are you doing, Fred?
0:52
Professor Fred Watson: Yeah, good to see you again, Heidi, as
0:54
always. And, um, yes, this could be the
0:56
longest goodbye ever. Couldn't it really? It
0:59
could go on for weeks.
1:01
Heidi Campo: It's like when you, uh, are parting ways with
1:03
someone, you say goodbye and then you realize
1:04
you're walking the same direction.
1:06
Professor Fred Watson: Yeah, yeah, exactly. I know. Yeah. I do that
1:08
all the time.
1:10
Heidi Campo: And then I never quite know. It's like, well,
1:11
do I keep talking to them? Do I say goodbye
1:13
again? Do I pretend they're not there?
1:16
I usually end up commentating and narrating
1:18
the whole thing to make it more awkward.
1:21
Um, well, anyways, let's just jump into
1:24
our questions because you guys have some
1:27
really fantastic questions, as always, which
1:29
we appreciate. Our first question of the
1:32
evening is a written question from John
1:34
Kerr. And John says,
1:37
hey, space nutters. This dilemma is driving
1:40
me nuts. If the moon's gravitational
1:43
pull has such an effect on our Ocean's
1:45
tides, for example, a, uh, 30 centimeter
1:48
rise in tidal waters twice a day, that's a
1:51
lift of 300 kg worth of water per
1:53
meter square. Why doesn't the moon's gravity
1:56
affect us as drastically as the
1:59
oceans? I will sleep better once resolved
2:02
with. Thanks.
2:05
Oh, so I have so much. I have so much. I feel
2:07
like I could say about this one too. But
2:09
please get Fred.
2:11
Professor Fred Watson: You might give a better answer than me,
2:12
Heidi. Um,
2:15
so it. Yes, well, it does. The
2:18
moon's gravity does affect us as drastically
2:21
as the oceans because we go up and down with
2:23
the oceans. Uh, in fact, the land itself
2:25
goes up and down slightly. If I remember.
2:27
It's about a foot or something. Oceans
2:30
sometimes go, uh, much, much more
2:33
than that. Um, that 30 centimeter that
2:37
John mentions. Uh, you know, sometimes it's
2:39
many, many meters. So what's, um,
2:42
happening here? It's. The critical
2:45
feature of tides is that they
2:48
are caused because of the
2:51
difference in the gravitational pull
2:54
of a body like the moon. And let's just think
2:57
about the moon and the Earth. Uh,
3:00
it's a difference between the moon's pull on
3:03
one side of the earth and the other side
3:06
of the Earth. So tides are all about
3:08
the difference in the gravitational pull of
3:10
an object, uh, across the diameter of
3:13
another object, a big object, and that's the
3:16
Earth. And so, um, the reason why our
3:19
bodies don't stretch and shrink is that we're
3:22
only, you know, we're only a couple of meters
3:25
tall. Uh, actually my son's a two meters
3:27
tall, but that's quite tall. All right, one
3:29
and a half meters tall. But we're certainly
3:32
not, uh, tens of thousands of kilometers,
3:34
uh, which is what you need for the
3:37
gravitational effect to be noticeable,
3:40
um, as it is with the ocean tides. So
3:43
we don't get stretched and um,
3:45
shrunk. We would if we were near a black
3:47
hole. That's the principle of
3:48
spaghettification. It's when your feet feel a
3:51
higher gravitational pull than your head head
3:53
and you get turned into spaghetti. Uh, that's
3:56
a uh, tidal effect, uh, an extreme
3:59
tidal effect. But um, you need
4:02
something very peculiar like a black hole to
4:04
notice that. So for, ah, an
4:07
object like the moon, we simply just go up
4:09
and down with the oceans. If we're on the
4:11
ocean, we go up and down with the land if
4:12
we're on the land. But we don't get stretched
4:14
and shrunk because we're too small.
4:17
I hope he's Jonas. I hope you sleep better
4:20
after that.
4:21
Heidi Campo: Well, maybe I'll scare him because I was
4:23
gonna say, but it does affect us
4:26
a little bit. Not like the oceans at all.
4:29
But the human body is roughly
4:31
60% water and every cell in our body is
4:34
roughly 70 to 80% water. Now
4:37
what I'm about to say next is not something
4:40
I'm looking at a science review for. It's
4:42
more anecdotal. But, um,
4:45
nurses will all stay like often
4:48
say that there is way more um,
4:50
emergency room activity on a full moon.
4:53
Police officers will say that people are
4:55
crazier on a full moon. And there's a lot
4:58
of lore around women's cycles
5:01
aligning, ah, with moon cycles. Um,
5:04
more women go into labor and give birth
5:07
around the moon cycles. And
5:10
historically there is a lot of
5:13
um, I guess stories
5:17
about personality around moons. You
5:19
think of werewolf stories. So humans do. We
5:22
are affected by the moon to some degree. And
5:25
that would be an interesting, probably
5:27
further research. And I'm sure there's whole
5:29
departments dedicated to the
5:31
psychobiological effects of humans and the
5:34
moon. But it is interesting. So no we're not
5:37
affected like the oceans but there is
5:40
some, something to that.
5:41
Professor Fred Watson: Absolutely. Yeah. And you, you, you're quite
5:43
right. You know this natural cycles that
5:45
align with um, with the moon and,
5:48
and it's not just humans as well with things
5:51
like coral spawning that's um, very much tied
5:53
to lunar phases. Uh and some of that's
5:56
not very well understood. Uh, but uh, I think
5:59
the thrust of, of John's question is
6:02
why, why aren't we being stretched and shrunk
6:05
like the oceans are? Uh, perhaps I've got it
6:07
wrong. But anyway that's the answer. Um, and
6:10
I agree.
6:16
Ben: Space nuts.
6:17
Heidi Campo: Our next question is an audio
6:20
question from Ben. Uh, with our
6:23
audio questions. We like to cue those up so
6:25
you the listeners can hear their question as
6:27
well. I'm just going to give Fred a second to
6:30
get his question ready as well and we are
6:32
going to play Ben's question for you now.
6:35
Ben: Hey guys, uh, it is Ben.
6:38
Um, American, living in Mexico.
6:41
Um, thanks for answering my last question
6:43
about how observatories interrupt
6:46
their observing schedules to deal with
6:48
transient events. And I've just got a follow
6:51
up question. Are there any,
6:54
any um, scheduled observing
6:57
things that uh, might be immune to these
7:00
sorts of interruptions? Um,
7:03
I know sometimes uh, there are time sensitive
7:06
observations of uh, like
7:09
transits or something um, that
7:11
astronomers use to determine shapes of ah,
7:14
objects and stuff like that that uh, need to
7:17
occur at a specific time. So I was thinking
7:18
maybe those are something that wouldn't be
7:21
interrupted. Um, but yeah, that's
7:23
my question. Thanks, loving the show.
7:26
Voice Over Guy: Bye.
7:27
Professor Fred Watson: That's a great question from Ben. Uh, and
7:30
Ben's absolutely right and he's actually
7:33
um, highlighted at least one of the uh,
7:36
the reasons why you wouldn't interrupt
7:37
observ. So um, his original question
7:40
was about what we might call target
7:43
of opportunity observations where uh,
7:46
an observer on the telescope would
7:50
stand aside if there was something
7:52
like a supernova explosion, uh, that
7:55
needed the same instrument uh to
7:58
observe it to give us something that was only
8:00
going to last for a very short time. And that
8:02
happens a lot. Um, the, the,
8:05
perhaps the best known of those was back
8:08
in 1987 which I remember very well when
8:11
that was the last time a naked eye
8:14
supernova uh, went off in our skies
8:17
down here in the southern hemisphere. It was
8:18
in the Large Magellanic Cloud, our nearest
8:21
uh, dwarf large dwarf galaxy.
8:24
Uh, it was visible to the unaided eye first
8:26
for 400 years. Uh and of course
8:29
the Telescope, our telescope was only 10
8:31
years old then. It was state of the art and
8:34
pretty well everything was pushed off for
8:35
observations of this, of this object.
8:38
Um, but um, it
8:41
is usually um, you
8:44
know, it's not usually uh,
8:47
an event, uh, where there will
8:50
be a conflict between the scheduled
8:53
observer and the person who was
8:56
requiring the target of opportunity
8:58
observations. It's uh, usually the
9:01
scheduled observer would have uh, uh,
9:03
had an understanding at the outset that
9:07
uh, they might need to stand by and um,
9:10
let somebody else take over the telescope for
9:13
the purpose of whatever their observations
9:16
are. However, uh, Ben's
9:18
absolutely right. There are some observations
9:21
which are scheduled which themselves are time
9:24
critical. And so you would rule
9:26
out the telescope being taken over
9:30
uh, for those events. Uh, one I was
9:32
involved with, um, because I was astronomer
9:35
in charge of the telescope at the time. And
9:37
this is probably 10 years ago there was an
9:39
occultation of Pluto.
9:42
Um, so what that means is
9:46
uh, actually it was an occultation of a star
9:48
by Pluto. What that means is Pluto passed in
9:50
front of a distant star, uh, and
9:53
we could observe the brightness of the star.
9:56
And what we wanted to do was
9:59
look uh, at the way the star's
10:01
light um, diminished uh, as
10:04
it passed through Pluto's atmosphere. This
10:06
actually it was before um, New Horizons
10:09
flew by Pluto in 2015.
10:12
So we didn't really know much about Pluto's
10:14
atmosphere. It's very thin, very tenuous. But
10:17
the observations that were made actually
10:18
allowed us to um, you know, form
10:21
details of it. In particular that it's quite
10:23
layered. It's not a smooth, smoothly changing
10:26
distribution. So that was very much a time
10:28
critical observation. And you would not get
10:31
uh, even if there'd been a bright supernova
10:34
uh, in the sky that night, it probably would
10:36
not have taken over the telescope. I think it
10:39
would have, uh, the occultation
10:42
by uh, Pluto would have been, would have been
10:44
the thing. And as uh, exactly as Ben says,
10:48
occultations are when an object passes in
10:50
front of a star usually or another object.
10:53
Uh, but it's a way of allowing us to work out
10:55
the shapes of asteroids and things of that
10:57
sort if they pass in front of a star. So
10:59
that's really quite, quite important
11:02
observations and very much time critical in
11:04
themselves. So you wouldn't want them to be
11:06
taken over by others. But it's a great
11:08
question.
11:09
Heidi Campo: It was a really interesting one. Yeah, it
11:11
kind of gives us the inner workings of
11:12
astronomy.
11:14
Our next question, um, I'm actually going to
11:17
read two questions because they are
11:20
similar, but we want to get both
11:23
questions perspectives. So the first one
11:25
we're going to read is from David and
11:28
David says hello Heidi and Fred. My
11:31
question is regarding meteor showers and why
11:33
we keep seeing them annually. If meteor
11:36
showers such as Persidius occur
11:39
when the Earth passes through the debris left
11:42
behind by comets as they orbit the
11:45
sun, what prevents the Earth from clearing
11:48
the debris from our orbital path after
11:51
the first pass, leaving our orbit free of
11:53
debris until the next comet pass, uh, uh,
11:56
next comet comes past. Cheers
11:59
Dave. And then we have
12:02
Brian with his question which is similar.
12:05
And then Brian says, can you explain the
12:08
orbital dynamics associated with annual
12:11
meteor showers? We orbit the sun, but
12:14
the whole solar system is rotating around the
12:16
Milky Way, which itself is moving. So
12:19
is the comet trail in a static stripe of
12:22
debris which we bisect on the same
12:25
point in our orbit total in our orbit each
12:27
year or is it in the orbit
12:30
of the sun or a galactic
12:33
center or other? If it's in our
12:36
solar orbit, why do we catch up with it? And
12:39
why don't we effectively leave a hole in the
12:41
debris diminishing the meteors every year
12:45
from the dark state, uh, from the dark
12:47
stars. North Yorkshire Moons
12:50
National Park.
12:53
Professor Fred Watson: Yeah, the national, It's North Yorkshire, um,
12:56
Moors National Park. It's a place I know well
12:58
in fact, uh, in the north of England and
13:01
they do have dark sky, dark stars. Uh, this
13:04
is from Brian there. I wonder whether Brian
13:06
knows my friend Paul Cass who also works at
13:08
the North Yorkshire Moors Dark Sky
13:11
Park. Anyway, that's a different uh, aspect
13:13
of all this Heidi. Um, and I might mention
13:16
that um, they've uh. Dave who
13:19
had.
13:19
The other question was from, from Inverell
13:21
here in New South Wales. So a question from
13:23
the UK and a question from Australia, both
13:25
effectively asking the same thing which I
13:27
thought was uh, worth while bringing
13:30
these two people together. So yes,
13:33
the, the bottom line is, and you've got to
13:35
sort of think of it in three dimensions, um,
13:38
it is to do with the orbits of
13:41
comets. Uh, a uh, comet
13:44
moves in a usually a very elongated
13:46
orbit. Um, and the sun is um, one
13:49
end of um, uh, passes close to
13:52
the sun and then disappears into the depths
13:55
of the solar system. Uh, when it gets near
13:57
the sun, uh, the comet starts
14:00
basically projecting dust, uh,
14:03
and that dust trail remains within
14:06
the comet's orbit. And so those dust
14:09
particles are sort of moving with the
14:12
comet. They're um, moving in the orbit as
14:14
well. But they smear out because they've got
14:15
their own uh, motion. And so
14:19
essentially ah, a comet leaves a trail of
14:21
dust exactly in its orbit and
14:24
if that orbit intersects the Earth's orbit,
14:27
then the Earth will pass through the trail of
14:29
dust. And that's exactly what it does. And
14:32
when that happens, that's when we get a
14:34
meteor shower. But the reason why,
14:37
um, you know, it doesn't soak up all the dust
14:39
as it goes through is because that dust
14:42
itself is moving. Uh, and, um,
14:45
it's not just a single dust cloud that you're
14:48
punching a hole in. The dust is a stream of
14:51
stuff that's moving through space with the
14:53
same velocity, more or less as the comet had.
14:55
Uh, and so what you've got is a region of
14:58
space that's rich in dust, but it's being
15:00
replenished, um, by the motion of the
15:03
particles. So, yes, the Earth plows through,
15:06
uh, doesn't really make a hole in it because,
15:09
you know, we only sweep up,
15:12
um, 12,000 km diameter
15:15
worth of it, because that's the Earth's
15:17
diameter. Um, and the dust stream might
15:20
be many, uh, tens of thousands
15:23
and perhaps even millions of kilometers, uh,
15:25
wide. Maybe not millions, but certainly
15:28
tens, hundreds of thousands, possibly.
15:31
So you've got a wide trail of dust that is
15:34
a reservoir for the Earth to
15:37
sweep up and see the meteor showers. So
15:40
it's constantly being replenish. That's the
15:41
bottom line. Uh, and hopefully that's the
15:44
answer to both those gentlemen's questions.
15:47
Voice Over Guy: Oh.
15:47
Heidi Campo: Ah, that is fantastic, Fred.
15:51
Generic: Okay, we checked all four systems, and.
15:53
Heidi Campo: Being with a girl, space nuts, I'm getting
15:56
sad.
15:56
I'm gonna do my last question now. Unless.
15:58
Unless I'm back next week. We will see.
16:01
So backstory for. For um, those of you who
16:04
might be new listeners, our regular host,
16:06
Andrew. He's been on a cruise around the
16:07
world and he's back now, but he
16:10
has quite the conundrum. Uh,
16:14
getting settled back in. We'll let him tell
16:16
you all that story and him and Fred get
16:18
caught up when. When he is back. But he's had
16:21
quite an exciting time.
16:23
All right, so our last question is. Excuse
16:25
me. An audio question from Lou.
16:29
Voice Over Guy: Hello, Heidi, and, um, Fred. My name is Noah
16:31
from Manchester, England. I'm asking
16:34
question about the Goldilocks Zone. The
16:36
Goldilocks Zone is only habitable for
16:39
life on, uh, Earth. For estrus rescues,
16:42
however, they might need to exist at the very
16:44
edge of the solar system or at the very
16:47
center of it. Is the Goldilocks Zone nearly
16:49
compatible for all life in the universe? Love
16:52
the podcast. Hope you keep making more.
16:54
Professor Fred Watson: Lovely question from Lou. Um, Manchester,
16:57
again, a place I know well. I grew up not
16:59
very far from Manchester in the north of
17:01
England. So this has been a bit of, a, bit of
17:03
a nostalgia segment for me. Um, but the
17:06
great question, uh, you know, is the, is
17:09
the Goldilocks Zone applicable to all
17:12
extraterrestrial life? And I think the answer
17:15
is no. Uh, because
17:19
we, when we talk about the Goldilocks Zone,
17:21
it's that region surrounding a star where
17:24
the temperature is not too hot and it's not
17:27
too cold, but it's just right for, for life
17:29
to exist. It's why it's called the Goldilocks
17:32
Zone. I've got a feeling it was a colleague
17:33
of mine who coined that expression as well. A
17:36
long, long, um, uh,
17:39
it relies on the fact
17:42
that we are, ah, beings. In
17:45
fact, all life on Earth is
17:47
uh, based uh, on water. We use water
17:51
as our working fluid. Uh,
17:54
as you mentioned, um, in our question on
17:57
tides, Heidi, most of our bodies are made of
18:00
water. Uh, and the same is
18:02
true of most living organisms. Uh, water
18:05
is a large part of it. And so
18:08
liquid, uh, water is for us,
18:12
uh, the,
18:14
perhaps the strongest feature that
18:18
um, might be used
18:22
as an indicator of where life might form. If
18:24
you've got water, maybe you will have life.
18:27
That's always been the mantra. Follow the
18:29
water. Um, so the
18:32
Goldilocks Zone is where you could put a
18:35
planet and it would be capable of having
18:37
liquid water on its surface. Not frozen, not
18:39
vapor, but liquid, which is what we need.
18:42
So it's very specific is the Goldilocks Zone
18:45
to um, life forms that are like
18:48
ourselves, that are based on water and.
18:51
Yeah, well, maybe if there is life anywhere
18:53
else in the universe, it will be based on
18:55
water. But there are other possibilities as
18:58
well. And people have wondered whether
19:00
perhaps the season lakes of Titan,
19:03
one of Saturn's moons, uh, whether. Which
19:06
are made of liquid ethane and methane,
19:08
whether they might have, uh, living
19:11
creatures in them that rely on those
19:13
supercooled liquids as their working fluid.
19:16
We don't know. We've not seen any evidence of
19:18
that. But it is possible. And so if that was
19:21
the case, then you'd be looking at entirely
19:23
different type of Goldilocks Zone. If
19:26
liquid natural gas was what you needed,
19:29
uh, for these creatures, uh, then your
19:32
Goldilocks Zone will be a very different one
19:34
from the one that we have. It will be much
19:36
further from your parent star. Uh, so
19:38
Goldilocks Zones are not universal. They're
19:41
not, um, kind uh, of, you know, common
19:44
to all species because
19:47
we don't know enough about what other species
19:49
might be like. But it's a good start. That's
19:52
why we look at the Goldilocks Zone with
19:54
interest because the only life forms that we
19:56
know use water. Uh, and Goldilocks
19:59
Zone is where water might exist. So that's
20:02
why we look there.
20:04
Heidi Campo: Fred, have you ever seen that TV show, I
20:06
think it's on Netflix or Amazon, called
20:09
Alien Worlds, where they. They break
20:12
down scientifically the conditions that would
20:14
be needed for. For different life on
20:16
different planets. Then they hypothetically
20:18
come up with a planet that's a
20:21
certain way. Have you seen it?
20:23
Professor Fred Watson: M. I haven't, but it sounds like one that I
20:25
ought to see.
20:26
Heidi Campo: It's very interesting. And that might be one
20:28
that Lou's interested in, because they come
20:30
up with four hypothetical planets. One of
20:33
them's a jungle, one of them's a desert. One
20:35
of them is, um, the
20:38
atmosphere is so dense that it's
20:41
almost like water. So there's all these
20:44
animals that look marine like, but they are
20:47
like birds. And it's very cool just to play
20:49
around because they use real physics and then
20:52
talk about the hypothetics. It's kind of fun.
20:54
Then I won't tell you about the last planet,
20:56
because it's kind of a. It's a fun surprise.
20:58
It's a fun surprise planet. It's not Earth.
21:00
It's not Earth. Um, it's a very
21:03
interesting hypothetical planet. Um, but I do
21:06
recommend that show.
21:08
Professor Fred Watson: Sounds great. I'll check it out. Sounds,
21:10
Heidi.
21:11
Heidi Campo: Yeah, it's a good one.
21:13
Um, well, I guess that's it for our Q
21:15
and A episode. So I just want to say, if this
21:18
is my last episode, that it has been an
21:20
absolute pleasure and delight being on here.
21:23
Thank you all for your wonderful and kind
21:25
questions. Fred, thank you for having me. If
21:27
y' all want to stay in touch, you can follow
21:29
me on LinkedIn. My. It's just my name, Heidi
21:32
Campo, which is C, A, M, M, P, O.
21:35
And then I think it's on. There is comma, C
21:37
S, C S, which is one of my certifications.
21:40
That would be Comet sun, if we're spelling
21:43
it phonetically. Comet son. Comet son. So,
21:46
Heidi Campos, C.S.C.S. if you want to follow
21:48
me on LinkedIn, I'm also on Instagram, but
21:50
it's mostly just pictures of my dog and me
21:53
talking about fitness stuff, which may not be
21:55
everybody's cup of tea. Um, Fred,
21:57
it's been a delight. Thank you.
22:00
Professor Fred Watson: Oh, it's been a delight for me too, Heidi.
22:03
And, um, I hope we do this again sometime.
22:06
It might be next week, but. It might be next
22:08
week.
22:08
Heidi Campo: It might be next week. Yeah, we'll be in
22:11
touch. And I'm. I'm always here if you need
22:13
me. Um, till then,
22:15
we'll catch, uh, you all next time.
22:17
Professor Fred Watson: Take care.
22:20
Voice Over Guy: To the Space Nuts podcast, Mission complete
22:23
Eastern. Available at Apple, Apple Podcasts,
22:26
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22:28
favorite podcast player. You can also stream
22:31
on demand at bitesz.com this. Has been
22:34
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22:36
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