Heidi Campo: Welcome back to another fun and exciting
Q and A episode of Space Nuts.
I am your host for this episode, Heidi Campo. And
joining me is Professor Fred Watson,
astronomer at large.
Voice Over Guy: 15 seconds. Guidance is internal.
10, 9. Ignition
sequence star space nuts. 5, 4, 3,
2. 1. 2, 3, 4, 5, 5, 4,
3, 2, 1. Space nuts
Astronauts report. It feels good.
Heidi Campo: Fred, how are you on this fine day?
Professor Fred Watson: I'm very well, thanks, Heidi.
And, um, I'm, um, delighted to see you again
because it is always a pleasure to take our, uh, listener
questions, uh, especially on a nice fine.
What is here in Australia, Winter's morning?
Uh, uh, it's a sunny day, as we
often get in wintertime in Sydney.
Heidi Campo: Well, you'll be delighted to hear that it has
finally stopped raining here in Houston, Texas.
The sun has come back out, starting to forget what it looked
like. But, um, we will be going
camping this weekend, so I'm looking forward to that. I
will, um, report back to you guys next week what, uh, the
weather from West Texas looks like.
Professor Fred Watson: If you get any great photos, Heidi, we should try and
post them on the Space Nuts website.
Heidi Campo: Oh, maybe I'll have to bring my telescope, uh, and do some
astrophotography out there. Actually, that's. I'm gonna, I
am gonna do that.
Um, and speaking of the United States, all of our
questions are from the U.S. this, uh,
this, this go around. And our first question
comes from dean from Washington,
D.C. doesn't get any more United States
than that. Dean asks,
um, are all neutron stars
pulsars in? If so, is it not
theoretically possible that a collapsing star has
so little angular momentum that it doesn't pulse?
If not, what else can a neutron
star be?
Professor Fred Watson: So, um, yeah, this, this, this
question has a simple answer. No.
Um, thank you, Dean.
Heidi Campo: Moving on.
Professor Fred Watson: I might elaborate on that a little bit. Um,
not all neutron stars are pulsars. And actually, look, I'm
going to take a direct quote from a NASA
website called Ask an Astrophysicist.
Doesn't come any better than that. Um,
because I love the opening of this little
answer. Most neutron stars in the
universe are old enough and tired enough
that they are no longer pulsars.
Um, and let me just interrupt
that quote by reminding us what
a neutron star and a pulsar is. A neutron star
is this highly collapsed object. It used to be a star,
but now we're seeing the collapsed core of the star,
only a few kilometers or miles across.
Uh, uh, what makes it a pulsar is
when it's spinning rapidly, uh,
and beaming radiation from its magnetic Poles.
So they behave just like a lighthouse, flashing, uh,
on and off, pulsing, uh, as the name implies.
So, uh, Dean's question is a good one. Are all
neutron stars pulsars? And they're not.
And as the NASA website says,
most of them are old enough and tired enough that they're no longer
pulsars. They've stopped spinning. Uh, and
just one, uh, further sentence on
that, which I think is quite illuminating. A recent paper
estimates 1000 million, what we call
a billion, normally 1000 million old
neutron stars in our galaxy in. Even though
the known number of pulsars, uh,
is only about 1000. So
there are many, many more neutron stars
that don't pulsate than there are that do
just because they've lost all their rotational energy.
So, a great question from Dean, um, sent
me to NASA's website, which is always a good thing.
Heidi Campo: I think they know the right answer.
Professor Fred Watson: One would hope so. Yeah.
Heidi Campo: I saw a T shirt in their gift shop a few weeks ago when
I was there, and it just. The Earth is round. We
checked. Love NASA.
I thought that was kind of cute and cheeky.
Professor Fred Watson: Yeah.
Heidi Campo: Our next question is from Ben,
who is actually a new listener. So thank
you, Ben, for writing in. This is, uh, so much
fun. Ben says, I came across the
podcast last week and I've been zooming through
it. I love the content. Thank you.
And then Ben goes on to say, I've got a question, and hopefully you
haven't already answered it on the roughly
450 episodes I haven't had
a chance to listen to yet. Um, but he
says one, when neutron stars and
or black holes merged to
produce gravitational waves, they lose mass,
which gets converted to energy, which
comprises. Which comprises of the gravitational
wave. But how does that conversion work?
Specifically? I'm thinking of a binary
neutron star system merging,
since my understanding is that the mass of the
neutron is quite consistent across the universe.
A reduction in mass would imply that a
reduction in the number of neutrons
would imply a reduction in the number of neutrons.
If this small leap of logic holds,
what determines which neutrons get converted
to energy? Are the faded neutrons
extracted evenly from throughout the
merging objects, or is there a region
that seems to be favored? And what
does this process of converting neutrons to
energy look like?
Ben is curious and hungry for answers.
Professor Fred Watson: It's a fabulous question, Ben.
Um, I've got a question for you, Ben, as well. How did you manage to get
through 450 episodes in
a week, less than a week? That
defies, um, probably the laws of physics. I
Think, uh, but that's all right because
apparently uh, merging neutron
stars also apparently derive
um, they, they break the laws of
physics. So um,
Ben, your question, as some of our
listener questions often do because they are so good,
sent me to the World Wide Web.
And the answer to this question is
quite, uh, it's quite subtle and there's
several things going on, partly because
we're dealing with very intense
gravitational fields. Uh, and
um, you know, to answer your question, are
the fated neutrons extracted evenly throughout the
merging objects or is there a
region that seems to be favored, um,
that probably relates to the
event horizon of the neutron stars because
they do have event horizons. Um, and
I don't think I'm capable of answering
that question. Uh, and
in any case it's more subtle than
just um, you know, neutrons getting thrown
away, uh, than what we were, than what
your question might imply. So
I would actually suggest, uh, Ben, that
you have a look uh, online,
uh, ah, at the uh, physics.stackink
exchange.com website,
uh, because
physics.stackexchange.com
has got a uh, very nice set
of question, question very similar to
yours and some quite lengthy answers
that go into some detail, um, and
look at different aspects of this question.
Um, so if you Google energy conversion from
mass to gravitational wave, the, that will take
you to this website and maybe
I can just um, you know, talk about
uh, one of those answers. And that is that
um, if you imagine, uh,
uh, one of the sort of subatomic particles and what
we call an alpha particle, which is the nucleus, a helium
4 nucleus, got two protons, two
neutrons, but its mass
is actually less than the
sum of those protons and neutrons.
And that's because there is something called
binding energy, uh, that's
released when that particle is
formed. And so uh, the
bottom line here is that mass and
energy are uh, highly interchangeable. When you're
talking about the kinds of things, the sort of
extremes that we are looking at in the
case of um, a neutron star, neutron star
collisions. Even in a neutron star doing its thing,
it's still extreme situations. And because
of the relationship that we're all aware of between
mass and energy, E equals MC squared.
That is, uh, why
you know, you've got this
potential to transform what looks
like a mass of a single particle,
uh, into energy, uh, to result
in a lower gravitational mass
for the pair of neutron stars. Sorry, the bottom line
here, which I should have said at the beginning, is that often when you've
got this neutron star, neutron star
collision, uh, you Get a
gravitational wave which
essentially, uh, has enough energy
to account for a difference in mass. It's not
just the sum of the two neutron stars that come together.
There is a mass loss as well, which we see as the
gravitational wave. And this is one of the mechanisms
that causes that. So have a look Ben, at
that webpage. Uh, and if you still
don't get it, ask us again, uh, and
I'll have another shot at it. But it is a really
interesting question and a good one too.
Um, um, got me thinking yesterday. I
was worrying all day about this
question, uh, trying to take my mind off the
root canal treatment that I was having at the dentist. At
the same time.
Heidi Campo: I also think of particle, uh, physics while I'm at the dentist.
Professor Fred Watson: It's the only thing to do really, isn't it?
Heidi Campo: So I actually, I will give my dentist a shout out.
My dentist, um, was one of my good friends
in, uh, doing my undergrad. And it was kind of cute
because the whole little cohort of us, we
um, started, we were in a powerlifting club in
my undergrad and uh,
we were just, you know, just a bunch of kids. And now he's
a grown up who's a dentist and we're all doing our
things. One of the other ones went on to be um,
a neurosurgeon. And so I'm like, it's quite a
little brainiac group of strength athletes.
So shout out to, uh, Dr. Gatlin
Marks, dentist at Platinum Dentistry
in Utah. On that's, you know, unprompted.
Not paid for free advertising, but he's great.
Professor Fred Watson: Well, I should advertise mine, shouldn't I?
Nothing like as nice a story, but I won't bother.
Heidi Campo: Space nuts.
Um, well, our next question is an audio question
from Craig and we are going to play that
question for you right now.
Professor Fred Watson: Hi professors, it's Craig down in
sunny Marimbula. Um, I've been
seeing items about James Webb, uh,
seeing really massive galaxies
much bigger than they, than current
cosmology expects. Are we
in an older universe? Could we
tell the difference between a big bang and a supermassive
white hole that's erupted into an existing space
time? They're just an uh,
overactive imagination. I hope you're enjoying your
week. Ciao.
Heidi Campo: All right, that was Craig's, uh, question.
Professor Fred Watson: Craig, the only person asking uh, a
question this week from.
Not from the usa.
Okay, his question about big galaxies,
is it telling us that the universe is older than we think?
Maybe, uh, that's a, it's a nice way of Thinking
about it, um, except that
we, we still,
you know, all the evidence points
to the
universe having a beginning which
was 13.8 billion years ago,
um, which, um, we think was,
um, the result of a, an event called the Big Bang,
an explosive event. Uh, we
believe that's the case partly because of what we observe today.
But we can also still see the flash of that Big Bang
by the fact that the light has taken 13.8 billion
years to get to us. So, um, it's
very hard to see how, uh,
if the universe was older than that Big Bang,
how galaxies would survive that
explosive event. Um,
so you know what, um,
Craig's question is about is,
uh, are, uh, there galaxies that are older than we think the
universe is? And
it defies logic. It's like saying,
um. And in fact, for a while, this was one of the problems
with the Big Bang theory. People thought, uh, the
um, planets,
uh, stars and atoms were actually older
than the measurement of the age of the universe that
we got. And that was one of the problems for the Big Bang theory,
uh, which was, uh, only really resolved in
the 60s, 1950s and 60s.
Um, so
I think that's still a step of logic that
we're not prepared to dismiss,
uh, that yes, there is that, um,
the Big Bang does mark the start of, uh, the
formation of galaxies and the galaxies in the
universe. Um, I have a colleague and uh,
friend, uh, who's a, uh, very distinguished
astronomer in the uk, Richard Ellis. And
he is absolutely. He's a
cosmologist. He's somebody who looks at the history of the universe,
very interested in the history of the early universe.
He is absolutely certain, uh,
that those galaxies that we can see that
do look bigger and older than what we expected them to
be, uh, that they do not defy,
uh, conventional cosmology, that we can still,
um, you know, work out
theoretical models that would allow those galaxies still to
be young, even though they look more
advanced in years than we thought they
would be. So, uh, it's all about
our understanding of galaxy formation rather than
having the cosmology wrong, rather than having,
uh, the age of the universe wrong. So,
a good suggestion, uh, uh, but I think
we are still stuck with trying to understand how
these galaxies got so big so quickly.
Heidi Campo: And stuck is what it is. Sometimes
that's what I get excited about with space. There's
so many questions that have to be answered.
Other sciences are so defined, but space
is infinite for us to figure out.
Professor Fred Watson: Okay, we checked all four systems and.
Heidi Campo: Dealing with the space nets, our, um,
our last Question is from another curious
listener. Mark from Bloomington,
Indiana says hello there.
What might meteors look like to a person on the
surface of Mars or Venus, if that were possible.
The planets are at uh, extremes of atmospheric
density. But carbon dioxide is the primary
aspheric gas for each.
The primary aspheric gas for each. And there is very little
oxygen present compared to Earth and to
each other. Would meteors appear brighter or dimmer,
different colors travel faster or slower,
more or less likely to be seen given the thick or
thin clouds and the uh, clouds altitudes
more or less likely to strike the surface. Thanks
for any insights or even guesses.
Professor Fred Watson: I think we've been sprung here, Heidi. People have realized that we
just take guesses at these things.
Um, so it's uh,
it's another great question. You know, we uh, this is,
I think none of the questions that we've had today have
ever come in before. Uh, maybe,
maybe people have been speculating about the um,
the mystery of these early galaxies. But this is a
great question. What would meteorites, sorry, what would meteors
look like, uh, to somebody. Let's
just stick with Mars for now because that's the easier
one to deal with. I um, think Venus will
be a problem because the atmosphere is so thick, uh,
so opaque that uh, you probably wouldn't see any
meteors at all just because,
you know, there's very little transparency in the
atmosphere. Mars however, is different. Uh,
it does have clouds, but not as many as we have here on
Earth. Uh, let's get to the easy
question, the easy part of this question, uh,
which is, um,
Query. Are they more or less likely to
strike the surface? And the answer is they're more likely
because Mars's atmosphere is much thinner. It's less than
1% of the pressure of the Earth's atmosphere. That
means that um, it's uh, more likely
that a meteoritic object would
survive its passage through the atmosphere to
reach the ground. Um, and we do find
meteorites on Mars. There are many examples that the
uh, various Mars rovers have found meteorites on
the planet Mars. A uh, meteorite is
a meteor that's got as far as landing on the, on the
ground, but what they would look like in
the uh, in the sky, uh,
uh, doesn't really have that much to do with what the
constituents of the atmosphere are. Uh,
uh, because what you see when you see a
meteor, a shooting star is the fact
that it is simply um,
it's being um, heated up to
incandescence. It's not burning in the
sense that things burn
in the presence of oxygen. Uh, and that I think is the
thrust of, uh, Mark's question.
But what you're seeing is this thing shooting through the
atmosphere. It is meeting a gas. Uh,
the gas is providing some resistance, but
also a lot of friction on the outside of this
particle or stone or rock or baseball, whatever
it is that's coming in, uh, whatever size it is that's coming,
coming in. And that's what causes the brightness
of the meteorites being flashed into
incandescence by its speed rather than a
chemical reaction taking place. Um, that
would, um, make uh, that much difference. Although
certainly we do see evidence of the oxygen
in the light of some of these. So meteors on
Mars would look similar to what they do on
Earth. There's some dispute
because the atmosphere of Mars, whilst
it's also much thinner than Earth's atmosphere, is
distributed differently. You know, uh,
the way in which it falls off in pressure as you go
up in height, uh, is different from
what it is on Earth. So that might mean that the
height at which meteors start to glow
as they come through the surface, sorry, come through
the atmosphere of Mars might be different.
And if they were lower, if they were burning up lower down
in the atmosphere, then they would look a bit brighter than they
do here on Earth. If they were burning up higher in the
atmosphere, they would, uh, look a bit
fainter. And it's not quite clear which of those
is the case. Uh, there's some dispute among
the. Certainly the things I've read about whether they
will be brighter or fainter, but they will be much the same.
So, uh, we hope that maybe one
day when, uh, astronauts are
exploring, uh, but not colonizing
Mars, uh, that they might send us
back reports of meteors that they've seen in the night skies of
Mars. And maybe you'll hear about it on Space notes.
Heidi Campo: Maybe so. And it is my understanding that that
is one. I mean, there's so many concerns with Moon
to Mars missions. And a potential Mars colony
is it's not as safe. Our atmosphere does
surprisingly a lot to protect us. And that is,
um, in a lot of student design
competitions that is something they're really
asking for students to look at is, hey, how can we
protect potential analogs
or colonies or any other assets we put
on Mars? How do we protect those from these
constant, um, impacts? And
ah, that is really kind of an interesting question right now.
And that's not really my wheelhouse. But, um,
people in the engineering world are, um.
There's a lot of fun things for them. To do with those
projects.
Professor Fred Watson: Indeed. That's right. Look, it's a different world
from ours. Everything's
different. Uh, radiation, meteoritic
bombardment, all of those things. Low pressure, low gravity,
different world and a lot to think about if
we are ever going to have humans walking on Mars.
Heidi Campo: All right, Fred. Well, ah, this has been
another fantastic Q and A episode. I
always, I love the way you answer these questions. I
feel like, uh, every time we write in,
I feel like each one of us has an opportunity
to be a, uh, collaborator with you and
gets to experience what it's like to be on
this intellectual journey together. So keep
sending in your amazing questions. You guys are,
you guys are half of the brilliance of this show. So
thank you so much.
Professor Fred Watson: That's right. I agree there
wholeheartedly, Heidi. At least half. In fact, maybe more than
that.
Heidi Campo: Excellent. Well, thank you everybody to listening to
another episode of Space Nuts. We will catch
you next time.
Professor Fred Watson: Sounds great. Thanks again, Heidi.
Andrew Dunkley: Hi, Fred. Hi, Huw. Hi,
Heidi.
It's Andrew from the southwestern
Indian Ocean. We've just finished a seven day crossing
of the Indian Ocean and stopped yesterday at
the beautiful island country of
Mauritius. And it's winter there, but
the temperature was in the
uh, mid to high 20s. So,
um, yeah, if that's winter, I'll take it. It's been
beautiful. The seas were quite smooth after our, uh,
treacherous rounding of south, uh, southern
Australia. Uh, but now that we've left Mauritius,
we're heading into, into some heavy seas as we
move towards the Cape of Good Hope and
then come up the other side of Africa. But
Mauritius was absolutely beautiful, lovely, uh,
people, interesting story behind Mauritius.
It's a, an island that was discovered by
Arabian, uh, sailors. Uh, it was unoccupied,
so they moved in and uh, of course they brought their
slaves with them. Um, somewhere along the
line they handed us over to, um,
the Dutch and the Portuguese. Uh, the
Dutch kind of decimated everything they possibly
could. My wife's half Dutch, so I've got
to be careful what I say. But, uh, they killed off the
dodo bird, they destroyed most of the
forests. Uh, they killed off the
native giant turtles. Uh,
so, um, yeah, nothing like that is there today.
But then, uh, the French moved in and they
stayed there for a very long time until they were tipped out by the British.
And the British held sovereignty over Mauritius until
independence late last century. Beautiful
country, very rugged volcanic
landscape. Uh, saw, uh,
the volcano at the top that still, uh, exists. It's
dormant. It hasn't erupted for a long, long time. And I hope it doesn't because
it's got houses all over it. Uh, but, um,
just a, just a beautiful landscape. They speak French
and English as their predominant, uh, languages.
But the, but the, the native people who are originally, uh,
you know, from the slaves of South Africa speak
French Creole. So it's really, really
interesting mix of people. But, uh, a lovely country
and, and very, very much worth
visiting. Uh, and a very big Hindu
population as well. And so we
visited, visited a Hindu temple and the sacred waters
that were discovered by a Hindu many, many years ago,
uh, where people were blessing children and uh,
walking through the waters, which are just as sacred as the
Ganges, apparently. Uh, and um,
there was a little monument there to the sun
and the planets. So, uh, there was a little
astronomical connection,
uh, while I was there.
Anyway, that's where we're up to. Next stop will be
Cape Town. It's going to take us five days of sailing to get
there, so I'll report on that next time.
So hope all is going well with Space Nuts. See you soon.
Professor Fred Watson: You've been listening to the Space Nuts. Podcast,
available at Apple Podcasts, Spotify,
iHeartRadio or your favorite podcast
player. You can also stream on demand at bitesz.com
This has been another quality podcast production from
bitesz.com