Listener Questions 61.0158: Black holes, gold asteroids and gravitational waves in time!

Daniel and Jorge answer questions from listeners like you! Send your questions to [e-mail]

 

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Episode Transcript

Speaker 1 (00:07):
Hey, Daniel, what's the latest news in physics?

Speaker 2 (00:10):
We still don't know how anything works. Newsflash.

Speaker 1 (00:15):
That's not really news, is it.

Speaker 2 (00:16):
It's true every single morning.

Speaker 1 (00:19):
There's been no new discoveries in the last week or so.

Speaker 2 (00:23):
No, we learn stuff every year, but the fraction of
all knowledge we have remains approximately zero.

Speaker 1 (00:29):
You mean compared to the infinity of the universe or
how much you're already forgetting due to age.

Speaker 2 (00:37):
I think both are true. The denominator is infinite and
the numerator is true. It's decaying with time, Yes, exactly.
I may have reached my peak smartness a few years ago.

Speaker 1 (00:49):
Oh, I think I reached my peak smartness like when
I was five.

Speaker 2 (00:53):
Maybe you should have retired then, man.

Speaker 1 (00:56):
I wish I could have. Yeah, I could have been
playing golf for the last fifty years.

Speaker 2 (01:05):
There you go, folks. Advice to all you five year
olds out there, what's the advice? Be rich and retire earlier.

Speaker 1 (01:26):
I am Jorge, a cartoonist and the author of Oliver's.

Speaker 2 (01:28):
Great Big Universe. Hi, I'm Daniel. I'm a particle physicist
and the professor at UC Irvine, and I don't plan
to ever retire.

Speaker 1 (01:35):
What do you mean you'll have to like drag you
out of your office at some point, or you plan
to die in your office.

Speaker 2 (01:42):
I plan to die in this job, though I haven't
actually decided where physically that will be.

Speaker 1 (01:48):
I guess, Yeah, I guess you can work from work
and die from home. I guess. But really you don't
plan to ever, you know, not do physics.

Speaker 2 (01:57):
As so long as I can keep teaching and thinking,
then yeah, I'll keep doing it.

Speaker 3 (02:01):
Mmmm.

Speaker 1 (02:03):
You don't believe in like making room for the next
generation of physicists.

Speaker 2 (02:08):
They're all retiring at five. They don't need jobs.

Speaker 1 (02:12):
Well, you need room for the four year olds, you know.
But anyways, Welcome to our podcast Daniel and Jorge Explain
the Universe, a production of iHeartRadio.

Speaker 2 (02:20):
In which we make the whole universe our problem, to
figure it out, to explain it to you, to understand
how it all works, to break it down into its
tiniest little bits and make it make sense if at
all possible.

Speaker 1 (02:33):
That's right. We try to retire the ignorance that we
have about our universe and the beautiful cosmos that we
all live in, and we try to make headway into
your brain to help you understand how it all works
and what it all means about our existence.

Speaker 2 (02:49):
And step one to figuring it out is understanding what
we don't know is examining the questions we still have
in our minds. What is it that we want to
figure out? What can the usion do we have about
how things are fitting together? What topics remain completely unexplored
and unknown. And it's not just professional physicists and five

(03:09):
year olds asking questions about the universe. It's everybody. And
we want to encourage you, everybody out there who's listening,
who is curious about the nature of the universe, to
ask questions. Ask them of yourself, and if you can't
figure them out, ask them of us. Write them to
Questions at Danielandjorge dot com and you'll get an answer.

Speaker 1 (03:28):
Yeah, Because, as we said many times, the process of science,
the process of discovery and finding knowledge out there, starts
with questions, starts with people being curious about what they
see and what they think they don't understand.

Speaker 2 (03:40):
And if you write to us with your questions, you'll
get a reply at least even if it's not a
complete answer, Because some of these questions nobody knows the
answer to, so all we can do is fast forward
you to the current forefront of human.

Speaker 1 (03:52):
Ignorance, right, because sometimes asking a question of a scientist
helps them come up with new questions, right, or think
of questions and new ways in their research. Right. Has
anybody ever written you and you're like, WHOA, I never
thought about that before.

Speaker 2 (04:07):
People have definitely written to me with questions I've never
had myself, ideas I've never thought of all the time,
I don't know that any of them have like actually
spurred new research.

Speaker 1 (04:19):
Or maybe like a new way to think about what
you're doing.

Speaker 2 (04:22):
I think sometimes the way people ask questions forces me
to think about things in a new way. Sure, and
you know, always the process of teaching and explaining forces
you to examine your own understanding and shore it up
and make connections you didn't make before. So this whole
podcast is like deep in my understanding of physics because
I'm forced to go out there and make connections and

(04:42):
find explanations for things that I was pretty sure I understood.
But when you go to explain it, you can always
find holes in your understanding.

Speaker 1 (04:50):
Yeah, it's all the big conversations and we try to
make all of you listeners part of the conversation here
in our podcast, because sometimes in our episodes we answer
questions that we yet from listeners like you.

Speaker 2 (05:01):
As are right. Sometimes the questions that come in through
the inbox are fascinating or tricky or complicated, or I
just think everybody might enjoy hearing the answer, so we
select some to answer here on the podcast. Thank you
to everybody who sends in your questions.

Speaker 1 (05:16):
So today on the podcast, we'll be tackling listener questions.
Number sixty one, So Daniel, we're back to numbering these sequentially?
Or is this still a random number with a secret
code in it?

Speaker 2 (05:33):
This is not a random number with secret code.

Speaker 1 (05:35):
No.

Speaker 2 (05:36):
I like to be sequential because when people write in
and I tell them we're going to answer it on
the podcast, I like to tell them which episode to
wait for, So numbers are useful for that, though I
suppose I could name them. Also, this could be the
elephant episode, or we're going to have a Polka Dot
episode or whatever. Those are just as arbitrary as numbers. Yeah,
or or like random numbers too?

Speaker 1 (05:55):
Right? This could be sixty one point seven four five three?

Speaker 2 (05:59):
Sure? Why not?

Speaker 1 (06:03):
Aren't extractional names? That's right? Or you give me like
Elon Muskin and name things with weird symbols in them.
Then we'd have to struggle to pronounce them. Yeah, I
guess it is a podcast. We have to read things
out loud, so we could.

Speaker 2 (06:15):
Just give them weird sounds then you know.

Speaker 1 (06:18):
Oh, there you go. This is listener questions number and
then but then you have to also have to write them,
so that might be Yeah, maybe we should just stick
the numbers. Wow, it's like numbers are useful integers. Yeah. Yeah,
all right, so sixty one. I feel like we've been
increasing these numbers because I feel like we just a
few weeks ago we were at number forty three.

Speaker 2 (06:40):
Man, We've been doing about one a week for a
while now because we got so many more questions coming in.

Speaker 1 (06:45):
MMM. And so our first question comes from Augustine, and
his question is about the gravity of black holes.

Speaker 4 (06:54):
Hello, Danny on her head, this is your friend. I
have a crazy idea. We know that the gravity and
a black hole is so strong that it will reap
apart matter or what we call sometimes stagratification. My understanding
is that this will happen all the way until even
particles are pull apart. My brain now is thinking, okay,
what about quarts. If I'm correct, the stronger you pull

(07:17):
apart a couple of quarks, the stronger the force. And
when we put in a force to pull them apart,
we give them force enough to create a new one,
and they are always in pairs. So now we have
like four age sixteen and close quarts. So it could
be possible that inside black holes we have an infinite

(07:37):
machine of creating quarts that might even be so many
at some point that we create a new universe inside
a black hole. Or even more, what if all that
energy of the black hole turns into just quarts and
making the black hole disappear? Thank you?

Speaker 1 (07:56):
All right? Really fun question. Basically, I think he's asking
can he make spaghetti out of quarks?

Speaker 2 (08:03):
Well, you know all spaghetti is made out of quarks
and electrons, so yeah, but this is not a cooking show. Now,
I think he's asking a really hard question about what
happens to particles inside a black hole.

Speaker 1 (08:17):
Now we're talking about black hole, so I suspect the
answer will be we have no idea. But Augustine is
sort of a friend of the podcast, right.

Speaker 2 (08:24):
Yeah, that's right. Augustine has his own Spanish language podcast,
which you should go and check out Kurt Gasidad Scientifica.
It's excellent and he and I have been in conversation
about physics for several years and I think he wrote
this in to try to stump me.

Speaker 1 (08:37):
Cool, So go ahead and check out that podcast, even
if you don't speak Spanish. I imagine it's interesting.

Speaker 2 (08:44):
You'll either learn physics or Spanish.

Speaker 1 (08:45):
Yeah, are both?

Speaker 5 (08:47):
Oh my goodness. Yeah, all right, So the question is interesting.
I think the question is like what happens to a
particle as it goes into a black hole, Because we've
talked about before this idea of spa gutification. As you
get near a black hole, the intensity of the gravitational

(09:07):
feel is so high that it sort of rips you apart.

Speaker 2 (09:09):
Right, Yeah, that's exactly right. Gravity is very very powerful
near a black hole. And if you have a physical extent,
if you're not just a point particle, like if you're
a little blob, then gravity on one side is going
to be stronger than gravity on the other side, and
that means you're getting pulled harder on one side, and
that's equivalent to being pulled apart. So, for example, if

(09:29):
you are near a black hole, and your feet are
closer than your head, then the black hole is trying
to pull you into spaghetti. So it's like trying to
pull your head off of your body and your feet
off of your ankles, because it's pulling on those things differently.
That's where spaghettification comes from. It's the tidal forces of
the black hole, not directly the strength of the gravity
of the black hole, but the difference in its strength

(09:50):
as you get closer or further.

Speaker 1 (09:53):
Right, because gravity depends on distance, right, gravity gets stronger
the closer you are to the source, just like gravity
stronger here on Earth than it is out there in space.
But sometimes the difference can be so big that it
can be enough to rip you apart.

Speaker 2 (10:08):
That's right. Technically, the Earth is trying to rip you
apart because as you stand on the surface, the gravity
on your feet is stronger than the gravity on your head,
but that difference is much weaker than the internal strength
of your body, and so you're able to hold yourself together.
But that's not true near a black hole, because not
only is the gravity stronger, but the differences are stronger
because gravity gets weaker much faster with distance.

Speaker 1 (10:30):
Right, So it's super intense when you get close to
a black hole, and so like if you were to
jump in head first, you would get ripped apart. Now,
I think Augustine's question is what happens to a particle?
Does a particle get pulled apart? And maybe let's start
with an atom, like would an atom get pulled apart?

Speaker 2 (10:46):
Yeah, it's a great question, and there's a couple of
competing issues here. Like number one, the tile forces depend
on you having a physical extent. The further apart you are,
the greater the distance between one side of you and
the other, the greater the difference and gravitational force will be.
So if there's no difference between one side of you
and the other, if you're like a point particle, then
there's no title forces. So title forces only apply to

(11:07):
things that are not point particles. And you're right, an atom,
for example, it's not a point particle, and so in
principle an atom could get pulled apart. But atoms are
so tiny, really really small, that the title forces are
going to be super duper tiny compared to like the
strength of the nuclear forces holding it together.

Speaker 1 (11:25):
Right, I guess it's not just about how much gravity
there is it's about, like you said, the slope of
the gravity, or like the intensity of or how quickly
gravity is changing, Like the difference between one end of
the atom and the other end of the atom has
to be large enough to overcome those forces. But is
that possible? Though? It is kind of possible, isn't it?

Speaker 2 (11:44):
In principle it is if you take the general relativistic
view of black holes a singularity, then as you get
closer and closer to the singularity, the curvature is just increasing.
And you might argue, well, the curvature has to be
crazy high for the title forces to compete with the
ternal strength of an atom. But then you can just
keep moving closer to the singularity to get arbitra early

(12:05):
strong gravity. And so, in principle, somewhere inside a black hole,
if there is a singularity there, you can get close
enough to it that the tidal forces should overcome the
strength of the bonds holding an atom together, and an
atom would get spaghetified.

Speaker 1 (12:20):
So it wouldn't happen outside or as it goes in,
it would have to happen way in there.

Speaker 2 (12:25):
Yeah, I did the calculation once, and outside the black
hole the gravity is not strong enough to spaghetify atoms.
But inside Again, if there is a singularity and we
don't know that there is, then in principle you could
get close enough inside.

Speaker 1 (12:38):
Well, doesn't it depend on the size of the black hole,
Like the heavier and more intense the black hole is,
the less close you have to get to the center
to maybe rip apart an atom. Hmm.

Speaker 2 (12:50):
Although if you can get arbitrary close then it doesn't
really matter what the mass of the black hole is
because you're decreasing that distance parameter. But yeah, for larger
black holes you don't have to get as close.

Speaker 1 (13:00):
Did it even get to the center? Like, doesn't time
stop as you get to the edge or the surface
of a black hole?

Speaker 2 (13:06):
Yeah, that's a little bit tricky. That depends on who's looking.
If you're in the outside of a black hole and
you're watching things fall in, then time slows down for
those objects according to you, and you never see them
fall into the black hole. But for the object itself,
time proceeds normally and they just fall in past the
event horizon and proceed towards the singularity and reach it
in finite time. General relativity is very tricky when it

(13:29):
comes to whose time we're talking about.

Speaker 1 (13:31):
Right, But to the rest of the universe, it would
never happen.

Speaker 2 (13:34):
Right, for the rest of the university, it would never
happen if it's the last thing you throw into the
black hole. As you approach the black hole, the black
holes of vent horizon actually grows out to meet you
because the power, the gravitational energy of the black hole
increases before the object crosses the event horizon. It's not
like it has to physically eat it and then it
pops out to be larger. So if you toss something

(13:55):
like a banana towards a black hole, it's event horizon
grows out or meet the banana, but never reaches it
unless you then throw an orange. That orange will pull
the event horizon out even further past the banana. So
the last thing to get thrown into a black hole
never actually reaches it, but earlier stuff will.

Speaker 1 (14:11):
Will it like will the banana actually reach the center
of the black hole? Or are things frozen in time
inside the black hole?

Speaker 2 (14:18):
Well, you can only answer these questions from the point
of view of some observer, and there's no observer on
the outside. They can see the inside of the black
hole from within the black hole, the banana reaches a singularity.
But I feel like Augustine is asking a question about
the interplay between the tidal forces and the strong nuclear
force inside that atom.

Speaker 1 (14:37):
Right right, Well, we said that it would maybe pull
apart an atom and maybe even a cord, but only
if it gets close to the singularity. I guess. I
mean then now the question sort of hinges like, will
it ever get close to that singularity?

Speaker 2 (14:50):
According to general relativity, things will approach the singularity, And
Augustine is asking about this interesting question that's trying to
balance this power of the black hole to pull basically
anything apart if it approaches a singularity, and the strong force,
which has this bizarre behavior that if you pull things apart,
it pops new particles out of the vacuum. And I
think he's wondering whether that's effectively creating an infinite amount

(15:12):
of mass.

Speaker 1 (15:13):
Mmm, oh, I see, all right, let's dig into his
specific scenario. So now we're imagining it that a quark
somehow gets inside of a black hole and it does
make it close enough to this singularity that they would
get pulled apart, or.

Speaker 2 (15:27):
I think imagine two quarks like you have a quark
antiquark pair. They're bound together into something like a pion,
or maybe you have three quarks within a proton, and
then those get pulled apart by the singularity. And when
those get pulled apart, there's now energy in that bond
which gets turned into mass in the form of new quarks. Mmm.

Speaker 1 (15:45):
So then what would happen? So now you have a
third quark that suddenly appears next to the other two.

Speaker 2 (15:51):
Yeah, actually you're going to get another pair of quarks.
So if you start, for example, with a quark antiquark pair,
and you pull them apart outside a black hole or
inside a black hole, with going to happen is that
there's a huge amount of energy stored in the strong
force between the two quarks. Because remember the strong force
is really weird, and the force between them doesn't decrease
with distance. As you increase the distance between the cork

(16:12):
and antiquark pair, the amount of energy in that bond
becomes enormous, and the universe prefers to convert that energy
back into mass, and it creates a new cork anti
cork pair, effectively reducing those distances. So you have like
cork antiquark now turns into cork antiquork cork antiquark.

Speaker 1 (16:28):
So like they multiplied or they just sort of like
divided the energy between two.

Speaker 2 (16:32):
Pairs, because I'm not sure what the difference is. Like,
you have one configuration with a lot of energy in
the bond. The next configuration, the one the universe prefers,
is to have lower energy in the bonds and have
more energy in the masses. The reason the universe prefers
that is that there's more possible configurations. That way, you
have more particles, they can get moved around a lot.
In general, the universe prefers to spread energy out because

(16:55):
it allows for more options. It's like an effective entropy.

Speaker 1 (16:58):
Okay, so then the black hole would split the cork
pair and make four quarks. And now what happens next.
Then those four quarks would fall into the black hole.
Would they also get split?

Speaker 2 (17:09):
Yep, those get split, and then you get more quarks,
and then those get split and you get more quarks.

Speaker 1 (17:13):
But at some point, don't you start to dilute the energy?
Isn't each subsequent pair of quarks don't they have less
energy in their bonds?

Speaker 2 (17:22):
Yeah? Exactly, And that's what happens in real life, like,
we do this at the Large Hadron Collider all the time.
We don't have a black hole yet, hopefully that we're
aware of. The lawyers require me to say. We create
quarks in it at quarks all the time, and we
create them in a way that they're flying apart. They
have a lot of velocity away from each other, and
so what happens is you get new pairs of quarks.
That energy is converted into mass, and eventually you got

(17:44):
a huge number of quark antiquark pairs and they're flying
away from each other, so that energy, that velocity gets
turned into mass. Effectively, what's happening here is something similar,
except you have gravitational energy. You're using the gravitational energy
of the black hole to basically pull the quarks apart.
That kinetic energy then gets turned into mass. So you're

(18:05):
turning the gravitational energy the black hole into mass.

Speaker 1 (18:09):
So you're just sort of like churning energy around. You're
not creating new energy, you're not destroying energy. You know,
the energy still stays within the black hole. It's just that,
according to your theories, there's going to be a lot
of weird slashing around in there.

Speaker 2 (18:23):
Yeah, exactly, and Augustine is wondering, like, does this turn
into an infinite amount of energy or where does this
energy come from? And the energy really comes from within
the black hole. It's just the gravitational energy of the
black hole. It's just like asking, hey, if you have
a particle near the edge of a black hole, doesn't
it accelerate as it gets towards the center of the
black hole? Where does that energy come from? That energy

(18:46):
just comes from the gravitational energy of the black hole.
It's converting the potential energy of the black hole into
kinetic energy of this particle. The thing about the black
hole is that doesn't change the overall energy of the
black hole. It still has the same total energy, which
is what in the end controls its gravitational power. So
it doesn't really matter what you do within the black hole.
Do you have quarks? Did you have the energy in

(19:07):
the bonds? You have it in the gravitational potential energy.
As you say, it's just sloshing around inside the black hole.

Speaker 1 (19:13):
But do you get like an infinite number of quarks
being made or is there at some point does it
stop popping off these new quarks or is it that
at some point. You know, the courts you create have
so little energy to them that there's just not enough
to make new quarks.

Speaker 2 (19:26):
It's a great question, and we don't actually know the
answer to it. In this simplistic model that I've drawn out,
where you have like a pure general relativity black hole
with an actual singularity in it, and then you have
these particles, you get an infinite number of quarks because
as you approach the singularity, there's always a place where
the new quarks are going to get rid apart to
make new quarks, to make more quarks. But the problem

(19:46):
there the infinity in the number of quarks comes from
the infinity in the singularity, which we don't think is physical.
So the real answer depends on knowing what's actually going
on inside a black hole, and the infinity in this
answer comes from the infinity and assuming that it's a singularity,
which is probably not true.

Speaker 3 (20:02):
Mmm.

Speaker 1 (20:03):
I see, so you're saying the answer is that we
don't know.

Speaker 2 (20:05):
We didn't know.

Speaker 1 (20:09):
We could just skipped the last twenty minutes. Daniel just
comes with my answer.

Speaker 2 (20:13):
No, you were totally correct right off the bat, because
we don't know how gravity and quantum particles interact we
don't even know how to calculate gravity for quantum particles
that have uncertain locations. So the right answer depends on
figuring out quantum gravity, which we have not yet done.

Speaker 1 (20:27):
Right, We don't even know if it'll make it to
the center, right, Like, we don't really know what happens
even beyond the event horizon.

Speaker 2 (20:33):
Right, Yeah, exactly right. There are some theories that black
holes have no center, have no interiors, all just smeared
on this sphericle event horizon, and there is nothing in
the bulk. All the information is just encoded on a
two D surface, that the black hole is not actually
part of our universe.

Speaker 1 (20:48):
Sounds like maybe the next question is not can you
make spaghetti out of quarks? Is can you make smir
out of quarts?

Speaker 2 (20:57):
All Schmeer has quarts in it, and in fact, the
Germans have a kind of spread called quark, which is
some kind of yogrity spread.

Speaker 1 (21:05):
It sounds like the Germans know the answer to this question.

Speaker 2 (21:08):
Perhaps the answer is probably one really long German word.

Speaker 1 (21:12):
Are there a German science podcast you've been on that
maybe could help us illuminate the topic? Here, you've been
on nine of them.

Speaker 2 (21:25):
I'm going to leave you in the quantum superposition of
thinking that was nine englishman. I think that was just
a bad pun. I think it was a pretty good pun,
or a pretty good pun.

Speaker 1 (21:35):
All right, Well, thank you Augustine for what do you
do in your podcast and also for sending us this question.
So now let's get to our next questions. We have
one here about golden asteroids and one about the effects
of gravitational waves on time, So let's get to those.
But first let's take a quick break where we're answering

(22:07):
listener questions here today on podcast number sixty one point
zero zero zero zero zero right now? Does a podcast
number have those decimals or is it a pure integer?

Speaker 2 (22:17):
I think it gets rounded by our heart processing system.

Speaker 1 (22:22):
I didn't know we had a process for rounding titles.
All right. Our next question comes from Mike, who comes
from Brooklyn.

Speaker 2 (22:31):
Hi, Daniel, and Jorge.

Speaker 6 (22:33):
Is it possible that somewhere in the universe there are
asteroids as big as our moon, made entirely of rare
metals such as gold or silver. How large an object
or system of such objects could there be? Thanks for
considering this question. You guys are the best and Katie
and Kelly are awesome co hosts too from Mike and Brooklyn.

Speaker 1 (22:55):
All right, thank you, Mike. Pretty cool question. I guess
the question is could you have a giant gold asteroid
out there?

Speaker 2 (23:03):
Yeah, and he wants a giant gold moon.

Speaker 1 (23:06):
Moon or a gold planet. Is that possible?

Speaker 2 (23:11):
I love the idea. Well it's a golden idea.

Speaker 1 (23:14):
Well, let's dig into it. What are the chances that
pure gold things are out there.

Speaker 2 (23:20):
There's definitely a lot of gold out there in the universe,
Like there is a lot of gold in the Earth,
and there are big blobs of gold in some sort
of like big heavy metallic asteroids. But the process by
which gold is made in the universe makes it, I think,
pretty unlikely to have like just a huge gold bar
floating out there in space.

Speaker 1 (23:39):
Hmmm, what do you mean? How is gold made in
the universe?

Speaker 2 (23:42):
Well, gold is a very heavy element, like many very
rare valuable elements, and it's so heavy that it can't
actually be made inside stars.

Speaker 1 (23:50):
Right.

Speaker 2 (23:50):
The brief history of the universe is that we started
out with almost all hydrogen, and then we formed stars
after a few hundred million years. Those stars are hot
and dense enough to do fusion which can make heavier elements,
but only up to about iron. Up to about iron,
when you fuse nuclei, you actually gain energy that releases energy.
It powers the star above iron. It costs energy to

(24:11):
do fusion, so you're cooling the star, you're consuming the
star's energy. So stars basically make elements up to about iron.
Heavier things than that require more specialized conditions, like the
collisions of neutron stars or supernova collapses that briefly create
the conditions necessary to consume that energy and make the
heavier elements m.

Speaker 1 (24:33):
So you need a star to explode to make anything
above iron.

Speaker 2 (24:35):
Anything above iron is made either in supernova so star
explosions or in neutron star collisions. And it used to
be that we thought it was mostly supernova but then
recently observations of neutron star collisions have sort of tilted
the balance, and now we think that probably most of
the gold in the universe is made in neutron star collisions.
How do we do that, Well, some neutron star collisions

(24:56):
they've observed in a couple of different ways, Like they've
seen the gravitational waves generated by these really intense massive
objects orbiting around each other and then eventually colliding, and
they also observed them astronomically, like they saw light from
the same event, and from that light they can measure
like how much gold was created, because gold, like every
other element, has a very special atomic fingerprint. It tends

(25:19):
to glow in certain wavelengths and give off light in
certain wavelengths. So they're able to measure the amount of
golden clouds around this neutron star collision by looking at
the light that came from it. It's this new era
of multi messenger astronomy where you see the same event
in two different sort of channels, and our understanding is
still pretty fuzzy, but it suggests that like huge amounts
of gold were made, like more than the mass of

(25:41):
the Earth is made in each of these collisions.

Speaker 1 (25:43):
But I guess maybe a question is is it only
gold that gets made or is it all materials above,
you know, iron, get made in an equal amount or
is it sort of random.

Speaker 2 (25:56):
It's not just gold that gets made. It's all these
heavy elements get made these kind of special events in
supernova implusions, in neutron star collisions, and it's definitely not equal, right,
Some of these things are easier to make because the
pathways for them to happen. Some of these things are
very very unstable, so even though you make them, they
disappear very rapidly and then decay down into other stuff.
We had a whole episode recently with Kelly about which

(26:18):
elements are more common in the universe, where we dig
into the science and the chemistry of that. But basically,
you're making everything possible and then only the stable stuff
sticks around very long.

Speaker 1 (26:28):
Now, I know that in a supernova, I think what
happens is the inside of the star collapses and then
it bounces, and there's this huge shockwave. And as the
shockwave goes through the rest of the star, the outside
of the star, it basically squeezes things so much in
this shockwave that the neutrons and protons fuse together to
make these heavy elements.

Speaker 2 (26:47):
Right mm hmm, yeah, that's right. You need very high
pressure and very high temperature in order to create these
heavy elements, and you need a lot of energy because
these processes absorb energy rather than creating it.

Speaker 1 (26:59):
Now, is there a sort of a a propensity or
a tendency as the shockwave goes out to have phases
where it's making a lot of gold and then suddenly
it's making a ton of other elements and then suddenly
or is it all random all the time?

Speaker 2 (27:13):
Yeah, that's a great question. It's not something we understand.
It's an area of current research exactly how that's happening.
This shockwave physics is very complicated because it's very sensitive
to a lot of the details. It's not like, on
average it ends up doing the same thing a little
bit hotter, a little bit colder, or the shockwave starts
here or starts there, and the conditions of the shockwave change.
So that's something people are working on right now. They

(27:35):
have these really complicated models of what's going on inside supernova.

Speaker 1 (27:38):
So we don't know yet, but I imagine maybe the
conditions to make gold are maybe different than the conditions
to make lead or titanium, right, And so I imagine that
it's not just all random all the time. Maybe you know,
as the explosion goes out, maybe you get the conditions
for gold, and then suddenly the conditions change for something else, etc.

Speaker 2 (27:58):
But it's also not clear that the condition are the
same across the whole star. The explosion might start in
one spot and then end in another. Spot, and so
you might simultaneously have different conditions across different parts of
the surface.

Speaker 1 (28:10):
But I imagine there has to be a reason that
you find gold nuggets on Earth, right, like all those atoms,
those trillions of atoms in a gold nugget must have
been made at the same time. Or do you think
they were made separately in different phases and somehow they
got together at some point.

Speaker 2 (28:26):
I think the formation of the gold that we find
here on Earth doesn't reflect how it is actually made
in the star. I think it more reflects the differentiation
process and the geology, the rock formation of what's happening
here on Earth. As the Earth cools. I think likely anyway,
gold made in these neutron stars comes out as a
huge fine spray, a mist, which then gets mixed out

(28:48):
into the universe, and you know these little granules that
then spread out. I don't think gold nuggets are formed
and then survive in that shape to be dug up.

Speaker 1 (28:56):
You're saying, maybe it all gets made as dust, gold dust,
and then when the Earth was like a big ball
of lava, maybe gold doest sprinkle throughout it. The gold
doest somehow, you know, settled in the same spot and
then stuck together.

Speaker 2 (29:11):
Yeah, that's exactly right. The Earth is formed from a
huge blob of gas and dust. Some of that is
little flecks of gold or heavier elements, and then as
that gets squeezed together into a planet, it gets hot, right,
and it gets molten, and then you have all sorts
of processes that happen. Like some of these elements are
called iron loving elements. They like to mix with iron
and they flow with the iron. So then as the

(29:32):
Earth is cooling, it differentiates and some of the heavy
things sink and some of the lighter things rise. And
the flow of those molten rocks and elements and oxides
and all sorts of complicated stuff determines where things end up.
And the big blobs that's why, like you get veins
of heavy metals or veins of copper here and there
comes from those molten flows, which then cool.

Speaker 1 (29:52):
But you're saying that out there in space in the supernova,
we're not sure if these things get made as dust
or as layer chunks.

Speaker 2 (30:00):
Yeah, we're not sure. I mean, I think it's most
likely because it's just the chaos and they energy this
process that it's spread out in terms of tiny granules,
But I don't know what the maximum size would be.
It's certainly possible that you get big ingots or even
enormous blobs. I mean, you can't rule out the possibility
that you're making like a blob the size of the
Los Angeles of pure gold. You know, quantum mechanically, anything

(30:22):
as possible.

Speaker 1 (30:22):
So in principle it could be What about these neutron
star collisions. Is the mechanism the same like a shockwave
or do things it made from the soup of neutrons
and quarts that make up the stars.

Speaker 2 (30:34):
Well, there definitely is a collision there and that creates
a shockwave through both neutron stars. Then they settle down
to form one bigger neutron star or a black hole
more likely if they're over the threshold now for a
neutron star to be stable, but we really don't understand
what's inside a neutron star and how that all works.
So we know that there's a process there that's capable
of creating these heavy elements, but we do not have

(30:55):
a detailed understanding of it. We don't even understand a
single stable neutron star, not to mention like two of
them smashing into each other, having complex shock waves bouncing
around inside.

Speaker 1 (31:05):
Because I think neutron stars are basically like a giant
ball of soup of neutrons and quarks, right, So, I
mean it seems possible you could just scoop up some
neutrons or quarks and then damn you certainly get a
giant gold planet.

Speaker 2 (31:19):
Well, neutron star is a little bit more complicated than that,
Like near the outside, they actually have a crust which
you can have some protons and electrons in it. Then
then we think there's probably a layer there's pure neutrons,
and below that we just don't really know, Like below
that probably doesn't even make sense to call it neutrons,
As you say, it's just like a soup of quarks,
like a quark gluon plasma, where the energy and the
density are so high that the whole idea of a

(31:40):
neutron doesn't really make sense. It's like a drop in
an ocean, right, you don't really call it a drop anymore.
And then below that we think probably there are new
states of matter, nuclear pasta or other weird exotic forms
of matter that only exist under these very high pressure
and temperature situations. So it's not just a ball of neutrons,
though there's plenty of neutrons there to play with.

Speaker 1 (32:00):
H all right, So it sounds sort of unlikely that
in our universe there have foreign moons or big asteroids
of just pure gold. Right. Although there aren't there giant
asteroids of pure iron out there.

Speaker 2 (32:12):
There are giant asteroids out there which are very metallic.
Like in our Solar system. We have a bunch of
different kinds of asteroids. There's like C type that have
a lot of water and ice in them, but there
is a kind called S type, which is a lot
of metal. For example, like a ten meters wide asteroid
might have like six hundred thousand kilograms of metal, including

(32:33):
like fifty kilograms of platinum and gold. And then there's
the M type, which are more rare, but they have
like ten times as much metal. So yes, these asteroids
do have a lot of metal in them, but they
start from the same basic materials as the Earth, and
so roughly they have like a random scoop of the
Solar system. It's just on the Earth, a lot of
this stuff is sunk down into the core and so

(32:54):
it's not as prevalent in the crust.

Speaker 1 (32:57):
So you're saying that there are metal asteroids out there,
but there are sort of a mix of metals.

Speaker 2 (33:01):
Yeah, exactly. It's not a pure gold asteroid, very unlikely,
or pure platinum. Most of these things are rocks with
a lot of metals mixed in and so, yes, they
are rich in gold and platinum. It's definitely out there.
But a pure gold asteroid or a silver asteroid, especially
when the size of the moon seems very unlikely.

Speaker 1 (33:19):
What about gold plated, I mean it is, you know,
sometimes that's just as violable.

Speaker 2 (33:27):
Well, you know, maybe we've been fooled and they actually
aren't filled with gold.

Speaker 1 (33:31):
They just covered it's a pure gold inside. It's just
a mix of metals on the outside.

Speaker 2 (33:36):
Well, you might wonder, like, how do we know the
composition of these things. It's mostly by looking at their
gravitational behavior. We can deduce their mass, and by looking
at their size, we deduce their volume, and that gives
us a sense of their density, and so we estimate
from the density of these things what they might be
made out of. For example, NASA is planning a mission
to an asteroid called Psyche, which is a big M

(33:57):
type asteroid. It's like two hundred kilometers across, and it's
so heavy, so dense that it has one percent of
the mass of the entire asteroid belt in this one
very metallic, very dense asteroid.

Speaker 1 (34:10):
WHOA. Well, I wonder if maybe Mike was also asking
the question, like could you make a giant moon out
of gold? Like would it hold?

Speaker 2 (34:24):
I don't think Mike was asking that. I think you're
asking that. I'm wondering what sort of like astro geoengineering
projects you have in mind over there.

Speaker 1 (34:31):
Well, he's asking how large an object there or such
an object could there be?

Speaker 2 (34:35):
Hmm, Yeah, that's a good question. In principle, you can
make an object about the size of the Earth, any
rocky object, anything primarily made out of heavier elements. You
can't really make it much bigger than the Earth because
then it's gravity just makes it denser and denser. You
can make about an earth sized blob of gold and
have it floating out there in the solar system.

Speaker 1 (34:55):
Whoa, it's a lot of bling for the solar system.

Speaker 2 (35:01):
That'd be a pretty cool engineering project. Like if you
come to an alien solar system and you find that
it's filled with like huge diamonds and Earth sized blobs
of gold. You might think like, Wow, these aliens know
what they're doing.

Speaker 1 (35:12):
Or maybe gold is so cheap that they can make
a whole planet out of them.

Speaker 2 (35:18):
Or maybe they've transcended the Kardashev scale and into the
Kardashian scale as you joked about it.

Speaker 1 (35:24):
Yeah, there you go. All right, Well, thanks Mike for
that question. I guess the answer is that it's not likely,
but still possible. In the end, we don't really know.

Speaker 2 (35:36):
In the end, almost anything is possible, but it seems
very unlikely for the universe to arrange for a gold
moon in our sky.

Speaker 1 (35:43):
Unless Mike is secretly a super trillionaire or something.

Speaker 2 (35:47):
If he finds that gold moon, he'll definitely be one.

Speaker 1 (35:49):
Yeah. Other then you have to wonder why he lives
in New Jersey.

Speaker 2 (35:52):
Oh he said, Brooklyn.

Speaker 1 (35:54):
Oh, Brooklyn, Brooklyn. Oh, well that makes more sense. All right. Well,
let's get to our last question of the day, and
this one is the effects of gravitational waves on time.
So let's get to that. But first let's take another
quick break where we're asking listener questions here today, and

(36:22):
our third question comes from Max.

Speaker 3 (36:25):
Hi, Daniel Dan JORGEV. This is Max calling from Stockholm, Sweden.
I have a question about gravitational waves, as they affect
the space, which has been proven in Bligo and Virgo,
do they also affect time the same way? Being compressed

(36:49):
and stressed as space, time is basically just one unit?

Speaker 1 (36:58):
All right? Pretty cool? Can you get wavy with time?
Is basically the question.

Speaker 2 (37:04):
Yeah. I love this kind of question because here again
he's bringing together two ideas we talk about all the time,
space and time are related. Gravitational waves or ripples in
space and time? Do they also affect time? Great question, Max.

Speaker 1 (37:18):
Right, because I guess we know from relativity that gravity
is not just about making things come together. It's about
distorting space, and it's not just about distorting space but
also distorting time. Right, Like a black hole not just
bends space around it, but it also bends time around it.

Speaker 2 (37:35):
Right. Yeah, that's exactly right. And there's a really important
progression of subtle ideas here as we go from like
Newton's idea of space and time to Einstein's special relativity
view of space and time where he brings space and
time together to one coherent object where they affect each other.
But we still have a clear sense of what time
is and what space is, and then into general relativity,

(37:57):
where concepts of space and time are much harder to
enter crprit out of our sort of generalized coordinates that
people use.

Speaker 1 (38:03):
So maybe Tarrika for our listeners. What is a gravitational wave?

Speaker 2 (38:07):
So gravitational wave is a wave in space time itself.
General relativity says we don't know what space time is,
but effectively, all we can do is measure the distances
between two points, Like we have this point here and
that point there. We can measure the distance between them,
and we can also measure the curvature of space, which
is how those relative distances change. So in space is curved,

(38:29):
things get closer together or further apart, depending on exactly
the nature of the curvature, and so ripples in that
curvature are gravitational waves because everything with energy creates curvature
in the universe. According to general relativity, if I have
a big massive object, then it's curving space and that's
what controls how things move around it. If I then
wiggle that object, then how I'm curving space is changing

(38:53):
with time because that information takes time to propagate out
from the wiggling object. So take a big black hole.
It's bending space. Now wiggle it, and you're making gravitational
waves from that black hole, waves in that curvature of space.

Speaker 1 (39:07):
Right. It's kind of like about the propagation or how
it spreads the effects and how the group's effects of
gravity spread out basically.

Speaker 2 (39:15):
Right, Yeah, if you wiggle a black hole, if the
curvature at a distant point doesn't instantly wiggle, right because
it doesn't know that you wiggle that, it takes time
for that information to propagate. And that's what the gravitational
wave is, is the propagation of that information.

Speaker 4 (39:29):
Right.

Speaker 1 (39:30):
Like, for example, if the Sun for some reason started
moving back and forth or wiggling or rocking back and forth, like,
we would feel that gravitational effect here on Earth, right,
we would feel that wiggling of the Sun gravitationally, like
the Earth would start to wobble too. But since it
takes some time for that gravitational effect to come from
the Sun to the Earth, that's kind of what we

(39:50):
call the wave, right, Like those wiggles as they propagate
out into the universe and then reach us, those are
the waves exactly.

Speaker 2 (39:58):
It's very similar to other kinds of waves. You take
an electron has an electric field. Now you wiggle that electron,
you're making wiggles in that electric field. Those wiggles are photons.
Those ripples are updating you about where the electron is now.
So the same way you can create ripples in the
electromagnetic field by wiggling an electron, you can create ripples
in space time by wiggling anything that has mass.

Speaker 1 (40:20):
All right, Now we've been able to measure those from
really incredible events that are happening out there in space.

Speaker 2 (40:26):
Yeah, it's really sort of amazing. Einstein predicted these things,
but he also said we may never see them because
these are very very small. We're talking about tiny changes
in the distances between objects. Like you hold two mirrors
a couple of miles apart. The distance between them might
change by less than the width of a proton as
the gravitational wave passes by. So these things are very

(40:49):
difficult to measure. But we actually have been able to.
They have these very sensitive interferometers. We shoot laser beams
between these mirrors that are very carefully isolated from everything.
Credible triumph of experimental physics. And they've seen them a
few years ago, and now we've seen dozens and dozens
of these things.

Speaker 1 (41:06):
Right, Well, as we've mentioned before, like everything moving, any
mass moving makes a gravitation wave. If I wave my arm,
I'm creating gravitational waves. They're just so small that nobody
can ever really feel them, although I have been working
out on my arm is pretty pretty massive lately.

Speaker 2 (41:23):
Technically requires acceleration, not just motion. But yes, any accelerating
mass will create gravitational.

Speaker 1 (41:29):
Waves, right right, Like if I wave my arm, right.

Speaker 2 (41:31):
Yeah, if you move it back and forth, that's acceleration,
and that will create gravitational waves. Those are so tiny
we'll never see them. Gravitational waves we have been able
to see are from super incredibly massive objects black holes
or neutron stars swirling around each other as they collide.

Speaker 1 (41:47):
Now, does it have to be acceleration, Like if let's
say an asteroid is moving in a straight line through space,
doesn't it create a ripple as it goes along too?
Because I like, I'm going to feel differently it's gravitation
attraction as it goes past me.

Speaker 2 (42:02):
Well, velocity is relative, right, and so the gravitational field
there doesn't depend on relative quantities. It only depends on
absolute quantities. Acceleration is absolute, and so you don't create
gravitational waves. Just by having a velocity. You can experience
a changing gravitational field, but that's not necessarily a gravitational wave.

(42:23):
Like if you're near the Earth and you're moving away
from the Earth, you're measuring a change in your local
gravity because you're moving away from the Earth. So time
dependence in your position and in your velocity. But there's
no gravitational wave created unless you have acceleration, which is
an absolute quantity.

Speaker 1 (42:38):
It's sort of a wave, right, Like if an asteroid
flies past me, I'm going to feel no gravity from it,
and then I'm going to feel a lot of gravity
as it's near me, and then I'm going to feel
les gravity as it flies away from me. Then I
sort of experience kind of a wave of gravity.

Speaker 2 (42:51):
Well, again, you experience a change in how much local
gravity you measure, Like if you get closer to an electron,
you're going to measure a stronger electric field, and if
you move away, you're gonna measure a weaker electric field.
But there's no electromagnetic wave there. It's just your motion
relative to the electron that's changing your local measurement.

Speaker 1 (43:08):
The effect is the same, though, don't I feel changing
my gravitational field over time?

Speaker 2 (43:15):
If you wanted to create exactly the same set of
local measurements, you wanted an oscillating gravitational field that you
need to move back and forth, and that's acceleration. So
you can't do it without acceleration.

Speaker 1 (43:25):
M Well, let's get to the question here. Now, we
know that a gravitational wave affects space. That's how we
measure them, right, Like we have giant rulers made out
of lasers very deep underground, and as they contract and
expand we know that a gravitational wave has passed by us.

Speaker 2 (43:44):
Yeah.

Speaker 1 (43:45):
Now the question is does it also affect time?

Speaker 2 (43:47):
Yeah? And the answer is pretty unsatisfying. The answer is
you can't really say yes or no because it depends
on what time means in general relativity, which is very
fuzzy and unclear. That's the short version of the unsatisfying answer.
The longer version of the unsatisfying answer. It takes a
bit of a tour through special relativity. Right, Like Newton says,

(44:10):
space and time are totally separate things. Things move through
space there obviously, time moves forward. Space and time are unrelated,
Einstein tells us in special relativity, No, no, space and
time are two parts of the same thing. It's a
beautiful realization that together they make a lot more sense
than a part. It's like electricity and magnetism fused together

(44:30):
into one idea makes much more sense than two separate ideas.
This is not to say that they're the same thing.
Two things can be two parts of the same thing
without being equivalent. Like you say the front and the
back of the elephant are two parts of an elephant.
Doesn't mean the front and back are the same thing.
So space and time are closely related in special relativity,
and space affects time and time effects space. But you

(44:51):
can always still say what is time and what is space?
Now we get to general relativity. In general relativity, the
coordinates you choose, like which direction things we're moving in,
are not so physical. They're just sort of like abstract,
and you can choose lots of different sort of systems
in order to do your calculations, like are using polar
coordinates or using xyz or lots of much more complicated

(45:15):
abstract coordinate systems, And some of those coordinates it's impossible
to say, like which direction is time and which direction
is space, they're all sort of mixed together. For example,
as you were saying earlier, what happens as you're going
inside a black hole, Well, time and space sort of reverse.
Right now, your future is the singularity. Every path into
your future ends at the singularity. Time and space have

(45:38):
sort of reversed roles there. That's just sort of shorthand
way of saying that we have a new interpretation for
the coordinates.

Speaker 1 (45:45):
Now I imagine this is super complicated, but I feel
like we're getting a little bit abstract here. Like I
wonder if Max is asking, you know, how in these
experiments where we can measure gravitation of ways, you can
see that the length of something changes as the wave
goes past. Does I wonder if he's asking, you know,
if I had a clog, would I see my clock

(46:06):
suddenly take a little faster and then take a little
slower as the wave goes past me.

Speaker 2 (46:10):
The answer is, you can't really separate it out into
the effects of space and the effects of time, and
the details of it dependent a little bit on exactly
how you've built your clock. Like let's say, instead of
having lego or you have lasers, and you're shooting lasers
back and forth to measure distance. You have like two
people far apart from each other, and they're constantly sending
each other little laser pings. Right like, I'm going to

(46:31):
send you a pulse of lasers every one nanosecond or something,
and then you're going to observe those We're going to
try to see if the time between the pulses changes
as the gravitational wave goes by. Right, Well, what's going
to happen as the gravitational wave goes by is that
those pings are going to get either red shifted or
blue shifted by the gravitational wave. But whether you interpret

(46:51):
that as like space expanding or time slowing down depends
in general relativity, on these coordinate systems that you've chosen.
So somebody could come along and say, look, I interpret
this as space bending. Somebody else come along and say, no,
I interpret that as time bending. In general relativity, most
people tend to work in what's called a synchronous gauge,
where you basically put all the bending into the space

(47:13):
part and you say time doesn't bend at all, And
that's just sort of like our interpretation. But it's totally
valid to say no, actually, time is doing the bending.
So the answer is sort of like, yeah, space time
as a whole is bending. Whether you call that space
bending or time bending is a little bit arbitrary.

Speaker 1 (47:30):
I wonder if what do you mean is like, let's
say a measuring time using a Grandfather clock, right with
like a swinging pendulum, and that's how measuring time. Now,
if the wave is coming let's say from directly at me,
and I face the Grandfather clock in one direction, then

(47:52):
maybe it's not going to fec how it takes. But
if I turn in ninety degrees, maybe it is going
to efac how it takes. And in which case you
might say in one instance that it did slow down time,
But in the other instance you might say, no, it
doesn't slow that time. It just stretched space.

Speaker 2 (48:08):
Yeah, that's right. And even in the case where it
did slow down time, you could argue it did it
slow down time because time actually went slower or because
increase the distance that the pendulum had to swing, Right,
You can interpret it both ways. Sort of how even
in special relativity you can interpret like contraction of distances
and stretching of time to be two sides of the
same coin, Like when I travel to a nearby star

(48:31):
at nearer the speed of light, I see the distance
to the star contracted, so it only takes me a
minute to get there. Somebody else sees me flying for
light years, but my time is slowed down, which is
why it only seems like a minute for me. So
I see length contracted, somebody else sees time dilated. In
many cases, it just depends on your perspective whether you're
calling it a space effect or a time effect.

Speaker 1 (48:53):
Well as it is super complicated. But I feel like
maybe in the past we've talked about or you've mentioned
there are separate effects in terms of the bending of
space and the slowing down of time, Like if you
swing by a black hole, then time will move slower
for you. Right, that's not up for interpretation, is it.

Speaker 2 (49:12):
You're exactly right that there are two separate effects we're
talking about here. One is like velocity dependent time dilation
or length contraction, which is a different effect than gravitational
based time dilation, which is just due to the curvature
of space. You're totally right, those are two separate effects,
and you're right that the gravitational one is an absolute effect.
It's not like I see your time slowed down and

(49:34):
you see my time slowed down and the gravitational one.
Everybody agrees, like the person close to the black hole
agrees that their time is going slower than the person
further from the black hole.

Speaker 1 (49:43):
So then what's happening as a gravitational wave goes past me?
Is it more like a black hole, like we're getting
far from a black hole, or is it more like
we're speeding up and slowing that.

Speaker 2 (49:53):
The gravitational wave is a curvature effects, so it's definitely
more like being close to a black hole. But I
was going to say that even the story with being
close to a black hole, we're interpreting that as an
effect on time. You can also change your gauge. They
call it in general relativity, redefine the axes and pretend
that it's only happening in space coordinates. So in general
relativity you can basically interpret these things as space or time,

(50:16):
because the distinction between the two becomes much more fuzzy.

Speaker 1 (50:19):
Even the case of going near a black hole. I me,
you just say that everyone can agree that time slow.

Speaker 2 (50:24):
Down, everyone agrees about the magnitude of the effect, and
if both of you agree on the co ordinates, then
we interpret that in terms of time. So, yeah, everybody
agrees that the person close to the black hole has
a stronger effect. If you're using a certain gauge, then
we interpret that as a time effect. If we choose
a different gauge, then we interpret that as a space effect.
The thing we agree on is the magnitude of the effect.

(50:46):
Whether it's space or time is up to interpretation.

Speaker 1 (50:49):
Wait, so then you already saying that when I go
near a black hole, I could interpret that not as
a change in time.

Speaker 2 (50:55):
Yes, you could choose some weird coordinates in general relativity
to interpret that as just a bend of space, because
it is a bending of space, right, that's curvature, And
so if you redefine your time, then you could choose
time to be invariant.

Speaker 1 (51:07):
Yeah, but it isn't the case. I mean, I know
this because I saw the movie Interstellar that if you
go near a black hole and then come back, you'll
be younger than me. That's not That doesn't seem like
it depends on a coordinate system. That's like, I'm gonna
see you're you're gonna be younger than me. There's no
way that I cannot see that.

Speaker 2 (51:24):
If one of us takes a trip to the black
hole and comes back, then you completed a loop. You're
back to the same location in space, and that makes
those calculations invariant. It actually doesn't depend in that case
on the choice of coordinates or gauges. So yeah, in
that case, like in Interstellar, everyone also agrees.

Speaker 1 (51:42):
All right, well, then let's mee just close it out then,
and what would say is the answer then? For Max's question,
does time get dilated as a gravitation away comes through
or can you just ignore it?

Speaker 2 (51:55):
I would say that space time does get dilated absolutely,
which part of space time? Saying gets stretched out is
a little bit arbitrary. Most people tend to work in
a choice of gauges where only space is getting stretched.
It's just sort of simpler, and it's more natural for
people to choose. But in the end it is a
little arbitrary because it really is all of space time

(52:15):
getting squeezed.

Speaker 1 (52:16):
All right, And if Matthew McConaughey were to serve a
gravitational wave, would he look come back younger or older?
Let he makes it too sure.

Speaker 2 (52:25):
I think he's frozen in time. He doesn't look like
he's aging at all.

Speaker 1 (52:28):
Right, right, that's what I mean that maybe that's a
secret he's serving gravitational waves up there.

Speaker 2 (52:33):
Yeah, we should all be in the Matthew McConaughey gauge.

Speaker 1 (52:35):
There you go, and then maybe we can all retire.
All right. Well, we tried, Max, Sorry, but it sounds
like the answer is that it's really complicated and you
need a degree in gravitational relativity to figure it out.

Speaker 2 (52:51):
But you're right that space and time are deeply, deeply connected.

Speaker 1 (52:54):
All right. Well, thanks to everyone who sent them their
questions here today. It's always fun to take a deep
dive into people's curiosity and to think about these scenarios
that we don't think about it every day.

Speaker 2 (53:07):
Absolutely, we love your curiosity, not just because it tells
us that our passion for wanting to understand the universe
is shared by so many other people, but because it
actually literally powers us. Your support for science and your
curiosity is what makes science possible. Thank you very much.

Speaker 1 (53:23):
Yeah, and if anyone ever makes a gold asteroid out there, hey,
how about you sent me a chunk of it, because
you know more about forty two years late on retiring.

Speaker 2 (53:32):
Yeah, so please donate a chunk of your next gold
asteroid to Jorge's retirement.

Speaker 1 (53:37):
Yeah, there you go. All right, Well, we hope you
enjoyed that. Thanks for joining us, See you next time.

Speaker 2 (53:47):
For more science and curiosity, come find us on social media,
where we answer questions and post videos. We're on Twitter, disporg, Instant,
and now TikTok. Thanks for listening, and remember that Daniel
and Jorge Explain the Universe is a production of iHeartRadio.
For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,

(54:08):
or wherever you listen to your favorite shows.