Could quantum clocks detect dark matter?

Daniel and Jorge talk about new ways to find dark matter, using space microwave ovens.

See omnystudio.com/listener for privacy information.

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:00):
If you love iPhone, you'll love Apple Card. It's the
credit card designed for iPhone. It gives you unlimited daily
cash back that can earn four point four zero percent
annual percentage yield. When you open a high Yield savings
account through Apple Card, apply for Applecard in the wallet
app subject to credit approval. Savings is available to Apple
Card owners subject to eligibility. Apple Card and Savings by

(00:22):
Goldman Sachs Bank USA, Salt Lake City Branch, Member FDIC
terms and more at applecard dot Com. When you pop
a piece of cheese into your mouth, you're probably not
thinking about the environmental impact. But the people in the
dairy industry are. That's why they're working hard every day
to find new ways to reduce waste, conserve natural resources,
and drive down greenhouse gas emissions. How is US Dairy

(00:44):
tackling greenhouse gases? Many farms use anaerobic digesters to turn
the methane from manure into renewable energy that can power farms, towns,
and electric cars. Visit us dairy dot COM's Last Sustainability
to learn more.

Speaker 2 (00:58):
As a United Explorer Card, you can earn fifty thousand
bonus miles plus look Forward to extraordinary travel rewards, including
a free checked bag, two times the miles on United
purchases and two times the miles on dining and at hotels.
Become an explore and seek out unforgettable places while enjoying
rewards everywhere you travel. Cards issued by JP Morgan Chase
Bank NA Member FDIC subject to credit approval offer subject

(01:21):
to change. Terms apply.

Speaker 3 (01:24):
There are children, friends, and families walking riding on paths
and roads every day. Remember they're real people with loved
ones who need them to get home safely. Protect our
cyclists and pedestrians because they're people too.

Speaker 1 (01:35):
Go safely.

Speaker 3 (01:35):
California from the California Office of Traffic Safety in Caltrans.

Speaker 1 (01:38):
When you pull up to game night, Ay, all new Camri,
but it's actually Bingo.

Speaker 4 (01:43):
Night miniglf anyone, It's a Camri.

Speaker 1 (01:49):
Five, the all new all hybrid Camri Toyota. Let's go places.

Speaker 5 (02:02):
Hey, Daniel, if you were Dark Matter, where would you hide?

Speaker 1 (02:06):
I wouldn't hide. If I was Dark Matter, I would
totally parade myself in front of all the scientists in
the galaxy.

Speaker 5 (02:12):
Ooh, a parade You mean like a pageant queen?

Speaker 1 (02:16):
Yeah, something like that. You know, just don't be so shy.

Speaker 5 (02:20):
Well, if it turns out you are dark matter, we'll
definitely throw you a parade. But so far, it seems
like dark matter is kind of reclusive, right, it's kind
of shy, so maybe it is hiding. What would be
some good spots for it to hide it?

Speaker 1 (02:32):
Well, if dark matter doesn't want a tiara and it's
hiding somewhere, then I don't know where it would hide.
I mean, if I knew, I would go and look
for it there.

Speaker 5 (02:40):
What if it's somewhere kind of obvious.

Speaker 1 (02:42):
Like what like right behind me?

Speaker 5 (02:44):
Yeah, or right in front of you or right on
TV and the Matter universe contest.

Speaker 1 (02:50):
That would be a great twist ending for the m
Knight Shamanlan version of this story.

Speaker 5 (02:54):
Well, man, do you think he knows I see dark matter?

Speaker 6 (03:13):
Hi?

Speaker 5 (03:13):
I'm Jorge Mack, cartoonist and author of Allor's Great Big Universe.

Speaker 1 (03:17):
Hi, I'm Daniel. I'm a particle physicist, and I wish
I had a dark matter tiara.

Speaker 5 (03:22):
Oh, but it wouldn't be very shiny or bright. It
would be dark, So what's the point. Also, when it
it just fall through your head.

Speaker 1 (03:30):
It would be hard to wear, but it'd be like
the greatest, most amazing piece of jewelry.

Speaker 5 (03:35):
Ever, how would you even keep it in your house?

Speaker 1 (03:39):
These are just like engineering details.

Speaker 4 (03:41):
You know.

Speaker 1 (03:41):
Once I've solved the physics of a dark matter Tiara,
I'll just pass that off to the engineers.

Speaker 5 (03:46):
This is just all part of your dream to be
the universe's darktor universe.

Speaker 1 (03:53):
I would like a little bit of bling. Yeah, you know,
physics bling would be nice. I'm not gonna win a
Nobel Prize anytime soon, So dark matter Tirres sounds good.
I see.

Speaker 5 (04:01):
I see. You could just say you have a dark
matter Tierra, and they know nobody would be able to
see it, or feel it or detect it. They would
just have to believe you.

Speaker 1 (04:09):
I need evidence, man, That's what science is all about.
You got to have data.

Speaker 5 (04:14):
I don't think those beauty contests depend on data very much.

Speaker 1 (04:16):
But I'm trying to win a science contest.

Speaker 5 (04:18):
But anyway's welcome. Podcast Daniel and Jorge Explain the Universe,
a production of iHeartRadio in which we enter you in.

Speaker 1 (04:25):
The greatest science contest of all time, the quest to
understand the nature of the universe. What is it, what's
in it? What's it made out? Of how does it
all work. We think these questions are deep and fundamental
parts of being a human being in this cosmos, and
unraveling these questions is a joy that everybody should share.

(04:45):
So on this podcast we take those questions apart and
try to share our answers and our ignorance with you.

Speaker 5 (04:51):
That's right, because science is the greatest beauty contest in
the universe. We're the goal is to discover the beauty
of how this universe is put together, how it works,
and what is our place in it.

Speaker 1 (05:01):
Over the last fifty one hundred years, we've developed a
pretty good sense for what's in the universe. We know
about stars and galaxies and all the bright and shiny
stuff that's out there in the universe. And we've also
figured out that there's a lot of the universe that
we can't see directly using our senses or any of
the forces that we've discovered except for gravity. We know

(05:22):
that a huge chunk of the stuff that's out there
in the universe is invisible. It's intangible, which makes it
very hard to discover and to figure out how to
make it into a tiara.

Speaker 5 (05:33):
Yeah, because it turns out that a pretty good understanding
of the universe only covers about uh five percent of
what we know is out there. The rest, the ninety
five percent of the universe that we know is there,
we have no idea what it is or how it works.

Speaker 1 (05:48):
That sounds like a good title for a book.

Speaker 5 (05:49):
Yeah, I think we wrote one, Daniel, which is available
for us sale everywhere.

Speaker 1 (05:54):
That's right. The kind of stuff that you and I
are made out of, atoms specifically, or what physicists called baryons,
only makes up five percent of the energy budget in
the universe. There's another twenty five twenty seven percent that's
dark matter, some kind of stuff that we know is matter.
We know it's out there, but we don't know what

(06:14):
it is, and we only have a very rough sense
of even where it is around us. The rest of
the universe is something we call dark energy, which is
contributing to the accelerating expansion of the universe, and we
have even less clue about what makes that up.

Speaker 5 (06:29):
Yeah, there's a lot we don't know, and it seems
like these are maybe the defining mysteries of our times
is to figure out what the universe is actually made
out of. Given that what we're made out of counts
is so little of it.

Speaker 1 (06:42):
Yeah, you're right, And in the last few decades there's
been a huge program of people looking for dark matter.
We've talked on the podcast about trying to make dark
matter in the laboratory by smashing particles together. We're searching
for the dark matter wind. We might be floating through
with very sensitive underground facilities looking for an individual piece
of dark matter to bump into liquid xenon, for example,

(07:05):
or maybe evidence of dark matter annihilating itself in the
center of the galaxy. But so far, none of these
experiments have found dark matter, which means we've got to
get creative about other ways to maybe detect this most
important or at least most common kind of matter in
the universe.

Speaker 5 (07:21):
So to be On the podcast, we'll be tackling the
question could quantum clocks detect dark matter? And how many
jargon words can we fit into one podcast title?

Speaker 1 (07:38):
I know it does sound like buzzword sound, you know,
like could we use AI generated crypto bitcoin to detect
dark matter?

Speaker 5 (07:46):
You mean quantum nano matter, Yes, exactly, quantum nano matter.

Speaker 1 (07:50):
Tiras Wow, I like quantum nanomatter. I'm going to use
that in a proposal.

Speaker 5 (07:54):
That's good, that's said Daniel. Also, it's probably our on
sale on Amazon. There's probably some product out there with
that name.

Speaker 1 (08:03):
So yeah, but you didn't say ching tm after it,
so I can use it.

Speaker 5 (08:07):
No, you don't have to.

Speaker 1 (08:09):
What I gotta brush up on my podcast property law.

Speaker 5 (08:13):
Yeah, you better or else I'm gonna see you for
nano dollars for nano bitcoins, you know what?

Speaker 1 (08:20):
Or hey, you can have all of my nano bitcoins.

Speaker 5 (08:25):
What's the price of bitcoin these days?

Speaker 1 (08:26):
Nano bitcoins zero? Yeah, doesn't exist.

Speaker 5 (08:31):
But anyways, it's kind of an intriguing title. Could quantum
clocks detect dark matter and quantum clocks sounds like it
does sound like something you could buy an off of Amazon.
Did you check to see if it's something you can
just get next day?

Speaker 4 (08:44):
Oh?

Speaker 1 (08:44):
Yeah, it turns out Amazon will sell you something it
calls a quantum clock, like a quantum entanglement led wall clock.
But none of these things are actually quantum clocks the
way that we understand them.

Speaker 5 (08:57):
Well, technically, isn't everything a quantum something? Well, I mean
not everything, but you know the five percent that we
know about in the universe, it's in it all quantum technically,
like this is a quantum podcast.

Speaker 1 (09:11):
I mean, that's a really interesting philosophical question and not
one that we really have an answer to, because on
one hand, you're right that everything is made out of
quantum particle, so isn't the whole universe quantum. On the
other hand, we know that when you zoom out things
behave by different rules. We call that classical. We don't
really understand why there is that transition, but there definitely
is a transition. So to call everything quantum is either

(09:32):
to say that look classical is just big zoomed out quantum,
or is to say that clackical doesn't really matter, which
doesn't really sit well with me. Or what if I
have no class, then you probably have a lot of
big coin.

Speaker 5 (09:47):
Then I'm not gonna win any beauty contest. I have poise,
but just no class.

Speaker 1 (09:52):
Yeah, exactly. But you know, for example, a clock that
just works on mechanical parts would also work in the
universe where QUANTUMU didn't rule the microscopic because it's not
sensitive to those microscopic details, and so that wouldn't be
a quantum clock. For example, like a pendulum clock or
an old fashioned Swiss gear based.

Speaker 5 (10:11):
Clock a discussion about now mankla Sure that's my favorite.

Speaker 1 (10:16):
Hey you brought it up.

Speaker 5 (10:17):
But anyways, it's a kind of an interesting question and
so we'll dig into it. But as usual, we were
wondering how many people out there have thought about putting
the concepts of dark matter and quantum and clocks all
together in one sentence.

Speaker 1 (10:29):
So thanks very much to everybody who participates in this
segment of the podcast. We love that you volunteer, We
love hearing your thoughts, and we love sharing your voice
with all of the other listeners. Please chime in if
you'd like, write to me two questions at Danielanjorge dot
com and you can't participate.

Speaker 5 (10:45):
So think about it for a second. Do you think
quantum clocks can be used to detect dark matter? Here's
what people had to say.

Speaker 7 (10:53):
I've never heard of a quantum clock, but I'm not
sure how it would be able to detect dark matter
anymore than a regular clock could. I guess maybe even
with a regular clock, you could send it out into space,
and if it hits a huge clump of dark matter
and therefore gravity, maybe we could learn that there's a
big well of gravity out in some location that we
otherwise couldn't detect.

Speaker 3 (11:13):
Not so sure.

Speaker 8 (11:14):
I suppose it's possible, but I have no clue how
it would Maybe something to do with entanglement.

Speaker 9 (11:20):
Since you're asking, the answer is probably yes, but maybe
still theoretical. I would think you'd have to use the
idea of measuring light passing through an area of more density,
thus possibly dark matter that causes curvature of space and
also time dilation. How to do that, I'm not sure.

Speaker 1 (11:39):
Since we don't possess a quantum clock, it doesn't seem
unreasonable to suggest that a non existent clock cannot detect
dark matter.

Speaker 5 (11:47):
All right, it's pretty uh intense answers here. I feel
like it's something that some of the listeners had heard
about before. Did you pull your professor colleagues this time?

Speaker 1 (11:59):
No, these are our listeners online. You know. There's some
good answers here about entanglement and light passing through areas
with dark matter density in them, and just in general
sense that this is a hard problem.

Speaker 5 (12:12):
Maybe you should ask a bunch of beauty queens next time,
or make it one of the standard questions in a
beauty pageant. Forget howdy, how would you save the world?
Or how would you know make things better? What do
you think about quantum clocks?

Speaker 1 (12:27):
Well, where is the dark matter? Yeah, I'd love to
hear that answer in the beauty pageant.

Speaker 5 (12:32):
Not that it couldn't happen, of course, no, absolutely. All right, Well,
let's dig into this intriguing question of whether dark matter
can be detected by quantum clocks, and let's start with
the basics. Daniel, what do we know about dark matter?

Speaker 1 (12:45):
So there's a lot that we do and do not
know about dark matter. So let's start with what we
do know. We know that it's out there, and we
know that it's here as well. We know that dark
matter is something that exists in the universe. And then
it's matter. We know that because we see its gravity.
We see it holding galaxies together as they spin. There
isn't enough gravity from the stars and the gas and

(13:08):
dust that make up those galaxies to keep the stars
in place as they swirl around the center of the
galaxy at very high speeds, and yet they do stay
in place. Galaxies are mostly not throwing stars out into
intergalactic space, and so we infer that there must be
some matter there to hold that galaxy together. But it's
more than just that one inference, that one fudge factor

(13:30):
to make that particular equation work. We see evidence for
dark matter all over the history of the universe, from
the very first few moments when the early universe plasma
is slashing around and you have dark matter and normal
matter and photons all acting very differently and creating different
slashing patterns. From looking at that slashing in the cosmic
microwave background radiation, we can figure out that there was

(13:53):
dark matter and even measure how much of it there is,
and we can trace the history of dark matter's gravity
as it shapes the structure formation of the whole universe
why we have galaxies at all this early in the
history of the universe, And so dark matter is definitely
out there as a kind of matter, but we don't
know really what it is or very specifically where it is,
because it's so hard to see since it only feels gravity.

(14:16):
It doesn't feel any of the other forces that we've discovered.

Speaker 5 (14:19):
And we can also sort of see dark matter right like,
we can see it in the same way that you
can see a lens or glass lens or example. You
can see how it distorts the light behind it, right.

Speaker 1 (14:29):
Yeah, exactly. We can see dark matter through gravity, and
so that means we can see stuff bending around dark matter.
We can see it holding galaxies together, and that even
impacts how light moves in the vicinity of dark matter.
If you have a big blob of dark matter between
you and some distant galaxy, for example, the photons from
that distant galaxy will bend as they move through that

(14:51):
dark matter, creating apparent distortions in your image. You can
even sometimes see the same galaxy twice in the sky
because of this gravitational lensing. And so we know that
it's out there, and we can use some techniques like
that to sometimes tell roughly where it is. But because
dark matter is so weak it's particles only feel gravity,
we think it's very difficult to figure out what exactly

(15:13):
is made out of to isolate one piece of dark matter,
because gravity is so weak that essentially a particle's gravity
is almost impossible to measure.

Speaker 5 (15:22):
Yeah, and dark matter is also something that's not just
out there in space. It's sort of like all around us,
right like it's floating through us right now, sort of
like the fourth you know, it flows through us, binds
us all together. It's made out of medtichlorians.

Speaker 1 (15:36):
Perhaps perhaps, yeah, exactly, you'll only really understand it after
nine hundred years of study. That's a really good question,
and that's sort of the central question of this episode
is exactly where is the dark matter? And can we
find like concentrations of it? Can we map it out?
Because dark matter is so weakly interacting like only gravity,

(15:57):
it takes huge amounts of it to feel anything, and
so that makes it very hard to tell exactly where
the dark matter is. It might be that it's mostly
spread out evenly through the galaxy. It might be more
clumpy than that depends a lot on your particular theory
of dark matter. Where it exactly is. So it could
be that we are in a dark matter wind as
the Earth orbits the Sun and the Sun moves through

(16:19):
the galaxy. We could also be in a dark matter
liss bubble, a bubble of space in which there's comparatively
little dark matter. Or it could be that dark matter
is fairly dense in our area.

Speaker 5 (16:29):
You know, I have to say, every time you say
dark matter wind, it makes me think of dark parts.

Speaker 1 (16:37):
Elevating the discourse every week.

Speaker 5 (16:41):
That's my job. That's why I'm here.

Speaker 1 (16:43):
Smells.

Speaker 5 (16:43):
It's all grounded or grounded or you know, flat as
in fletch wents. But anyways, so it's sort of all
around this, and I guess I'm wondering, like, if it
is all around us, would we be able to tell, Like,
you know, if let's say dark matter is flowing through
the Earth right now, or say it wasn't, would you
be able to tell the difference.

Speaker 1 (17:02):
That's exactly what these experiments are trying to measure. And
to give you a sense of the difficulty the challenge
of this, think about like why we didn't discover dark
matter earlier, just in studying how our Solar system moves.
We have now very precise measurements of the orbit of
Jupiter and Mars and all the planets and all the
little pieces of the Solar System as they orbit the Sun.

(17:24):
You might think, hey, if dark matter is here in
our Solar system and it has gravity, wouldn't it change
the way those things orbit? Shouldn't we be able to
detect it? But because we think dark matter might be
spread very thin, probably there isn't that much dark matter
in the vicinity of our Solar system. So even those
very very precise measurements you know, like knowing the motion
of Jupiter to meters or centimeters, can't detect dark matter

(17:47):
because it would be very thin and very spread out
and mostly we think homogeneous, which in the end doesn't
give much gravitational pull on the objects in the Solar System.
So it takes a very specialized, highly sensitive device to
be able to detect this dark matter.

Speaker 5 (18:02):
Yeah, and then don't we say once like, if you
take all the dark matter that is potentially floating through
the Earth right now, it would only weigh about as
much as a squirrel or something like that.

Speaker 1 (18:11):
Yeah, exactly, though that's very speculative, right. That assumes that
dark matter is essentially equally spread out in our galaxy,
which we don't believe is true. But if you assume
that there is, then we know our galaxy, for example,
is ninety five percent dark matter. That means for every
kilogram of matter made out of atoms like hydrogen and
helium or whatever, there's nineteen kilograms of matter made out

(18:35):
of whatever dark matter is made out of. And so
it's like nineteen to one in our galaxy.

Speaker 5 (18:41):
Which sounds like a lot, but I guess also galaxies
kind of very empty mostly right, like it's probably like
ninety nine percent empty.

Speaker 1 (18:48):
Yeah exactly. Now, normal matter clumps up a lot, right,
Like the Sun is an extraordinarily dense collection of normal matter.
Normal matter is not spread evenly through the galaxy. But
if you take dark man and spread it evenly through
the galaxy, you get a pretty small density. It's like
ten to the twenty six kilograms per cubic light year,
which is a huge volume, which means it's like ten

(19:12):
to the negative twenty two kilograms per cubic meter. So
then if you add up all the cubic meters in
the Earth, that adds up to about two thirds of
a kilogram of dark matter inside the volume of the Earth. Again,
assuming that dark matter is evenly spread throughout the galaxy,
which it probably isn't, but it might be.

Speaker 5 (19:30):
Roughly, which is about the size or mass of a squirrel.

Speaker 1 (19:34):
Yeah exactly, So one squirrel of dark matter inside the
volume of the Earth compared to you know, the many,
many millions and billions of kilograms of normal matter inside
the volume of the Earth. That sounds the importance of clumping, right,
Because normal matter clumps together, it's gravity is much more powerful.
In our local neighborhood, than dark matter. Even though dark
matter outweighs normal matter by nineteen to one, if it's

(19:55):
much more thinly spread out, the local effects of its
gravity are much harder to detect.

Speaker 5 (20:00):
I think maybe what you're saying is that dark matter,
in terms of the universe scale, it mostly hangs out
in galaxies. Like you don't see a lot of dark
matter floating out there on its own between galaxies.

Speaker 1 (20:10):
Yeah, we can do really precise measurements of where dark
matter is on the galaxy scale, because galaxies are really
really big. If we can tell how galaxies are orbiting
around each other, just the way we can tell how
stars are moving through the galaxy, so enormous clumps of
dark matter, absolutely, we can measure their gravity. But when
you zoom in in a really fine grained way and
want to say, hey, is there a moon sized blob

(20:31):
of dark matter anywhere in our solar system, that's a
tough question to answer.

Speaker 5 (20:35):
So then within the galaxy, you're saying, like, there's a
lot of dark matter within our galaxy. Ninety five percent
of the mass of our galaxy is dark matter, And
what does it look like. Does it look like, you know,
an intense dense ball of dark matter in the middle,
is it evenly distributed? And also, like our galaxy looks
like a disc sort of like a flat disk, is
dark matter also shaped like a flat disk.

Speaker 1 (20:55):
So we have the best answers the more we zoom out,
and then as we zoom in things get literally funny.
But on the scale of the galaxy we have some ideas.
We think that dark matter is like a big halo.
So imagine the visible galaxy right the edge of the stars.
Dark matter is a big halo that goes out beyond
the visible stars, and it's bigger and fuzzier. It hasn't

(21:15):
collapsed the way normal matter has because it just doesn't
clump right. In order to clump, things need other kinds
of interaction other than gravity. Like if you have two
dark matter particles they attract each other gravitationally and then
just passed right through each other. They're just gonna zig
and zag back and forth oscillate forever. They're not going
to clump together. To do that, you need like electromagnetism
or the strong force or something that wants to grab

(21:36):
onto each other. So dark matter stays a big puffy
halo and the galaxy is sort of embedded in that halo,
and that's not a coincidence. Right. The reason the galaxy
exists is because of a big dark matter blob there
that's gathered together all the hydrogen helium gravitationally and made
it into a galaxy. It's the reason we have stars, etc.

Speaker 5 (21:57):
Now, when you say halo, you don't actually mean like
an angel's halo that looks like a ring. You actually
mean just like a blob, right.

Speaker 1 (22:03):
Yeah, exactly, like a big fuzzy blob that extends out
further along the disc and then further above and below
the disc. But even that we know already is not
evenly distributed.

Speaker 5 (22:14):
Is it like football shaped? Is it kind of flat?
Or is it a perfect sphere.

Speaker 1 (22:18):
It's more like a hockey puck, right, It's flat, but
not as flat as the galaxy itself.

Speaker 5 (22:23):
What made it flat?

Speaker 1 (22:24):
Yeah, maybe a hockey puck is the wrong analogy. It's
not quite that flat. It's more like a big ellipsoid.

Speaker 5 (22:29):
You mean like a slightly squished ball.

Speaker 1 (22:31):
Yeah exactly. It's like a big basketball that somebody's sitting
on or something.

Speaker 5 (22:36):
All right, Well, let's get a little bit more into
the details of what we know about dark matter, how
much of it can we see, how much can we
discern about what it's doing in our universe? And we'll
answer the question of whether you can use a quantum
clock from Amazon dot com to detect it. So we'll
get to those questions, but first let's take a quick break.

Speaker 1 (23:02):
With big wireless providers, what you see is never what
you get. Somewhere between the store and your first month's bill,
the price, your thoughts you were paying magically skyrockets. With Mintmobile,
You'll never have to worry about gotcha's ever again. When
Mint Mobile says fifteen dollars a month for a three
month plan, they really need it. I've used Mintmobile and
the call quality is always so crisp and so clear.

(23:22):
I can recommend it to you, So say bye bye
to your overpriced wireless plans, jaw dropping monthly bills and
unexpected overages. You can use your own phone with any
mint Mobile plan and bring your phone number along with
your existing contacts. So dit your overpriced wireless with mint
Mobiles deal and get three months a premium wireless service
for fifteen bucks a month. To get this new customer
offer and your new three month premium wireless plan for

(23:44):
just fifteen bucks a month. Go to mintmobile dot com
slash universe. That's mintmobile dot com slash universe. Cut your
wireless bill to fifteen bucks a month. At mintmobile dot
com slash Universe, forty five dollars upfront payment required equivalent
to fifteen dollars per month New customers on first three
month plan only speeds slower before to gigabytes on unlimited plan.
Additional taxi, s, fees, and restrictions apply. Seement Mobile for details.

Speaker 8 (24:04):
AI might be the most important new computer technology ever.
It's storming every industry and literally billions of dollars are
being invested, so buckle up. The problem is that AI
needs a lot of speed and processing power, So how
do you compete without cost spiraling out of control. It's
time to upgrade to the next generation of the cloud.
Oracle Cloud Infrastructure or OCI. OCI is a single platform

(24:29):
for your infrastructure, database, application development, and AI needs. OCI
has four to eight times the bandwidth of other clouds,
offers one consistent price instead of variable regional pricing, and
of course nobody does data better than Oracle. So now
you can train your AI models at twice the speed
and less than half the cost of other clouds. If
you want to do more and spend less, like Uber

(24:51):
eight by eight and Data Bricks Mosaic, take a free
test drive of Oci at Oracle dot com slash Strategic.
That's Oracle dot com slash Strategic Oracle dot com slash Strategic.

Speaker 1 (25:03):
If you love iPhone, you'll love Apple Card. It's the
credit card designed for iPhone. It gives you unlimited daily
cash back that can earn four point four zero percent
annual percentage yield. When you open a high yield savings
account through Applecard, apply for Applecard in the wallet app,
subject to credit approval. Savings is available to Apple Card
owners subject to eligibility. Apple Card and Savings by Goldman

(25:26):
Sachs Bank USA Salt Lake City Branch Member FDIC terms
and more at applecard dot com.

Speaker 2 (25:32):
With the United Explorer Card, earn fifty thousand bonus miles,
then head for places unseen and destinations unknown. Wherever your
journey takes you, you'll enjoy remarkable rewards, including a free
checked bag and two times the miles on every United purchase.
You'll also receive two times the miles on dining and
at hotels, so every experience is even more rewarding. Plus,

(25:52):
when you fly United, you can look forward to United
Club access with two United Club one time passes per year.
Become a United Explorer Car Card member today and take
off on more trips so you can take in once
in a lifetime experiences everywhere you travel. Visit the explorercard
dot com to apply today. Cards issued by JP Morgan
Chase Bank NA member FDIC subject to credit approval Offers

(26:14):
subject to change. Terms apply.

Speaker 1 (26:16):
When you pop a piece of cheese into your mouth
or enjoy a rich spoonful of Greek yogurt, you're probably
not thinking about the environmental impact of each and every bite,
but the people in the dairy industry are. US Dairy
has set themselves some ambitious sustainability goals, including being greenhouse
gas neutral by twenty to fifty. That's why they're working
hard every day to find new ways to reduce waste,

(26:37):
conserve natural resources, and drive down greenhouse gas emissions. Take water,
for example, most dairy farms reuse water up to four
times the same water cools the milk, cleans equipment, washes
the barn, and irrigates the crops. How is US dairy
tackling greenhouse gases. Many farms use anaerobic digestors that turn
the methane from maneuver into renewable energy that can power farms, towns,

(26:58):
and electric cars. So the next time you grab a
slice of pizza or lick an ice cream cone, know
that dairy farmers and processors around the country are using
the latest practices and innovations to provide the nutrient dense
dairy products we love with less of an impact. Visit
us dairy dot com slash sustainability to learn more.

Speaker 5 (27:23):
All right, we're asking the question can you use quantum
clocks to deteg dark matter? And we've been recapping a
little bit about what we know about dark matter, Daniel.
How much of the details of it can we see?

Speaker 1 (27:34):
Not really very much. We have this sense of a big,
fuzzy halo that surrounds the galaxy, and we can also
measure the density as a function of distance from the center.
So if you're a star, for example, orbiting the center
of the galaxy, the speed at which you orbit depends
on the force that's holding you in that orbit. So

(27:55):
the stronger the force, the faster you can go, or
the faster you can go, the stronger the force that's
needed to hold you in that orbit. So by measuring
the speed of a given star, we can essentially measure
the mass of all that stuff that's holding on to
that star. So then if you look at stars at
different distances from the center, you can basically map out
the density of stuff in the galaxy as you go

(28:17):
further and closer to the center of the galaxy.

Speaker 5 (28:20):
Like, if dark matter was super condensed in the middle
of the galaxy, then the stars in the galaxy we'd
be rotating a certain way. Or if the dark matter
was more spread out then the stars in the galaxy
we'd be rotating in a different way.

Speaker 1 (28:33):
Yeah, exactly, if all the dark matter in the galaxy
was at the center, then everything would act in a
certain way, would just go like one over are squared.
It's sort of like the way the Solar system orbits
the Sun. But if you take some of that mass
and you spread it out through the galaxy instead, then
the dark matter that's further out than a given star
doesn't affect its orbit because it's gravity all cancels out.
So that changes the rotation speed of those stars, and

(28:56):
that's in fact how we first discover dark matter. Was
by looking at these rotation speeds of stars around the
center of the galaxy and seeing that we couldn't explain
it by mapping all the mass from the stars and
the gas and the dust. And that's exactly how you
can tell where you need to add more mass to
explain these rotation speeds. It's not just like, hey, add
a big blob of the center. You need to add
some of the center and also some further out and

(29:19):
some further out, and so precise measurements of those velocities
give you a fairly accurate picture of where the dark
matter is in the galaxy. And it's not evenly spread out.
It's more densely clumped at the center, which is something you'd.

Speaker 5 (29:31):
Expect because it is affected by gravity, right.

Speaker 1 (29:34):
It is, in the end affected by gravity, and so
it's pulled itself together. And the whole reason that this
exists is because of some like early universe perturbation where
you had a denser blob of dark matter that created
this whole well, gathered together the other dark matter and
created this over density which then pulled in hydrogen, helium
and whatever was around to make a galaxy. So it's

(29:56):
a little bit denser at the center, though it's not
very well understood, like if we do calculations simulations to
describe what we think should happen. If you have a
bunch of dark matter and you give it a few
billion years to fall together and to form some structure,
it describes what astronomers call a cusp, which means like
a point of high density of the center and then
very steeply falling should like drop off quickly. But if

(30:17):
you go out and measure the actual distributions of stars velocities,
you see something that looks like a bigger core. It's
not like it's pointing near the center. It's more spread
out in the inner galaxy. It's like flatter, and so
this is not something we understand very well. And it
also gives you a sense of like the scale of
which we can figure this stuff out. We're talking about
over light years distances, right, We're not resolving dark matter

(30:40):
in meters or even in aus with very very coarse
ways to measure where the dark matter is again, because
its gravity is so weak.

Speaker 5 (30:48):
Are you saying like the beginning of the universe, dark
matter was more evenly spread out, like you know, all
those light years of empty space between US and Andromeda
and other galaxies was all filled with dark matter, and
then it all colleutes through certain clusters.

Speaker 1 (31:01):
Yeah, it definitely gathered itself together. The early universe had
initial density fluctuations, and that's a whole big question about
where exactly that came from. And then those seated gravity
to pull things together. So gravity does form structure, but
it takes time. And so yeah, dark matter was more
spread out and now it's less spread out.

Speaker 5 (31:19):
Why would dark matter stay stuck together?

Speaker 1 (31:22):
Well, it's not that dark matter is sticking together. It's
not like it's bonded to itself. And again we don't
really know because we don't have a microscopic picture of
the dark matter. But I think you're asking, like, why
does dark matter form even gravitational structures? Like why does
it get more dense in some places and then in others?
Is that what you're asking?

Speaker 5 (31:38):
Yeah, Like I'm imagining at the beginning of the universe
there's a bit of dark matter that was, you know,
let's say, ten light years away, and then it got
attracted to our galaxy, so it flew over here. But
then why didn't just keep flying to the other side.

Speaker 1 (31:51):
Yeah, So as that distant piece of dark matter approaches
the galaxy, it gains velocity. Right, it's exchanging gravitational potential
energy for kinetic energy. And then you're imagining like the
way a ball rolls down a valley, why doesn't it
roll back up the other side? And it will, yes,
but then it comes back right, And so gravity in
the end is organizing something. There's the second piece to that,

(32:12):
which is that it doesn't completely roll back up the
other side. You know, anything that's accelerating is emitting gravitational
radiation for example. So the reason, for example, two black
holes orbiting each other will eventually spiral in and collapse
is that they're emitting gravitational energy. So none of these
things are really stable. So over long periods of time,

(32:33):
even without inelastic interactions like electromagnetism or whatever, these things
will form very large structures and they will gradually collapse
due to gravitational radiation.

Speaker 5 (32:43):
All right, so we kind of have a fuzzy picture
of where it is in the universe. So now the
question of the episode is can we use quantum clocks
to detect dark matter? How do quantum clocks fit into this?

Speaker 1 (32:55):
So quantum clocks might give us a sense for where
the dark matter is if we can find a place
where it's like clumpy, if we can find a place
in our solar system where it's like gathered together for
some reason. And that would be really cool, because not
only would it help us detect what dark matter is,
but it would help us understand where it is. It's
a really deep mystery. I think, not just because we

(33:16):
want to understand dark matter, but because we want like
a map. You know, humans are visual creatures. We want
to know like where the stuff is, and just not
knowing where dark matter is in the universe really bugs me.
So I would love to know where it is, and
understanding its map on a finer scale would be really helpful.
And quantum clocks might be able to help us map
where dark matter is if we can send them out

(33:38):
into space and if they're sensitive to dark matter, if
their operation changes as they pass through dark matter.

Speaker 5 (33:45):
Okay, I think you're saying that you know, at the
galaxy level, we know that it looks like a big blob.
It's sort of like a switch ball. It's sort of
more intense or more dense in the center of the galaxy.
But I think maybe you're saying, can we know in
finer detail what it looks like between stars within the galaxy,
like is it clumpy, is it chunky, or is it
like peanut butter.

Speaker 1 (34:06):
Smooth exactly, And people have tackled this problem in the past,
Like people use the technique you mentioned gravitation lensing to
look for blobs of dark matter, and that works, and
it's powerful, but only if you have like a really
nice galaxy behind the blob of dark matter that can
show you that it's there, so that tells us a
little bit about the dark matter density. But there aren't

(34:27):
like galaxies in all the right places to like X
ray the whole Solar system and figure out where it is.
And that technique isn't always powerful enough. You need like
a really big blob of dark matter. Another technique people
have used is to look for dwarf galaxies. Essentially, our
galaxy is formed by the combination of lots of galaxies, right,
we think galaxies formed kind of small and then grew
together with all sorts of absorptions and collisions. That means

(34:49):
that our galaxy has other like mini galaxies embedded within it.
Some of these we call dwarf galaxies because they're small,
and we think they're like very high dark matter density
therew stars, and so we can look at the motion
of the stars inside those little galaxies to get sensors
for like where those blobs are. But we don't have
a great way to like X ray the Solar System

(35:10):
and figure out, like where is the dark matter in
our Solar system? Is it hanging out by Jupiter? Is
it spread evenly like peanut butter? What's going on?

Speaker 5 (35:18):
You want to know it's distribution at the Solar system
scale exactly.

Speaker 1 (35:21):
That's what I want to do. And I read a
recent paper which was very clever, which is looking at
asteroids and trying to track asteroid trajectories and see if
like tiny little deviations in the trajectory of asteroids or
comets as they move through the Solar System could reveal
the presence of dark matter. It's very difficult to do
because if dark matter is evenly spread out or only
a little bit clumpy, that'd be basically no effect on

(35:44):
those asteroids. But it's the kind of thing that we're
just on the verge of being able to potentially do
now that we have better measurements and better computational tools
to try to like infer this information from really specific measurements.

Speaker 5 (35:56):
All right, So then how would you use a quantum
clock to deteg dark matter?

Speaker 1 (36:00):
So when we talk about a quantum clock, really what
we mean is something which is based on fundamental quantum
mechanical principles. And you know it sounds fancy, but even
just like an atomic clock, is a quantum clock. An
atomic clock is something that looks at like the oscillation
of electron between two energy levels and a caesium atom,
which is a very precise, very very regular process that

(36:21):
we can use essentially to tell how time has passed,
and so on Earth, we have extraordinarily precise atomic clocks
which now set the standard and in fact define what
we mean by a second. A second used to have
a different definition, but now a second is defined as
like a certain number of cycle of a specific kind
of atom. That's literally how we measure time now, and

(36:44):
so it's the standard.

Speaker 5 (36:46):
It's like the minute, like it used to be like
a minute with sixty seconds, but now people say, oh,
it's been a minute to really mean something totally different.

Speaker 1 (36:57):
Yes, it's just like that exactly, and we call it
a quantum clock because this really is a quantum process
we're talking about quantum particles. There's an electron, there's an atom.
The electron is moving in the potential well of the atom,
so it's interacting electromagnetically with the nucleus. And the way
that it's moving, the way it oscillates between energy levels,

(37:17):
is completely controlled by quantum processes. This is not a
clock that you could have in a perfectly classical universe.
You know, if we lived in a universe where electrons
really were tiny little balls that went to orbits and
had smooth classical paths the way planets do, then this
clock could not exist. And so that's when we meet
by quantum clock.

Speaker 5 (37:36):
But I guess, if it's a quantum clock, doesn't it
have a certain amount of uncertainty to it or unknowability?
How can it be precise if there's the Heisenberg uncertainty principle.

Speaker 1 (37:46):
Yeah, you're right, there's no absolutely precise quantum clock. But
this is about as regular as it gets. And amazingly,
these quantum clocks are more precise than mechanical clocks, which
of course also have uncertainty in them, because no mechanical
device is perfect created, right, And so this is as
accurate as they've been able to make them, and recently
they've been even able to make them small and transportable.

(38:08):
You might think of an atomic clock as like some
huge device in the basement of a laboratory in Colorado
that weighs like ten tons and fills a room. But
actually these things can be made quite small.

Speaker 5 (38:19):
So a quantum clock is really just an atomic clock
or is there another kind that doesn't use atoms?

Speaker 1 (38:24):
There's no atomic clock that's not a quantum clock. So
quantum clock is just a fancier sounding name for atomic clock.

Speaker 5 (38:29):
Yes, can you have a quantum clock that maybe doesn't
use an atom, that maybe just relies on electrons or
quarks or something.

Speaker 1 (38:35):
Yeah, sure, you're not limited to atoms. You can imagine
quantum clocks made out of like photons interacting or splitting
or bouncing or something like that. In some sense, lego
is a clock because it's measuring the time for photons
to travel along its legs, right, it's just converting that
to a distance measurement. And so you could have other
quantum clocks that are not based on atoms. Yes, And

(38:58):
one day, when we discover dark matter, maybe we could
build a clock out of dark.

Speaker 5 (39:01):
Matter, which may or may not tell you the time.

Speaker 1 (39:05):
And may or may not smell like flatulence.

Speaker 5 (39:07):
Well, I guess maybe give us an example of, like
what's a typical or popular or a commonly used quantum
clock and how does it work.

Speaker 1 (39:14):
Well, the most precise quantum clock is based on the
caesium one thirty three atom. That's the one that's actually
used to define what a second is. And so here
we have two states of electrons. There's a small splitting
in an energy in state here. It's called a hyper
fine splitting because the difference is very very small, and
when the electron sits in there, it sort of goes
back and forth between the two different states.

Speaker 5 (39:36):
Meaning like, this is an electron that's orbiting around the
caesium atom.

Speaker 1 (39:40):
Yeah, I wouldn't say orbiting if we want to be
really really technical, But it's captured by the caesium atom.

Speaker 5 (39:45):
And you're saying it's switching energy levels. Why would it
switch energy levels?

Speaker 1 (39:49):
So you have this caesium atom and you embed the
whole thing in some microwave radiation that can lift those
electrons up from the lower state to the higher.

Speaker 5 (39:56):
State, meaning you like put it in a microwave or
you shoot it with it like a light gun.

Speaker 1 (40:01):
There's not a difference, right, that's what a microwave is.
A microwave is shooting microwave radiation at your food, and
microwaves are lights. Though basically a microwave is a light gun.

Speaker 5 (40:10):
Sounds hot. So then you have this atom and you
you stick it in the microwave.

Speaker 1 (40:14):
Uh huh, yeah, So you stick in the microwave and
you measure how often it jumps up and then down
and then up and then.

Speaker 5 (40:19):
Down because the light, as the light passes through it,
it knocks the electron up and down or what.

Speaker 1 (40:25):
Yeah, the light is tuned to exactly the frequency for
the electron to jump up into the higher energy level. Remember,
electrons can go from a lower to a higher energy
level if a photon of the right energy comes along.
So they've tuned this microwave to exactly that energy level.
So electrons and the lower level can absorb these photons
jump up to the higher level. But then they'll naturally

(40:45):
decay down because the universe likes to spread energy out
and so the time of these oscillations turns out to
be very very regular, Like an electron will do this
nine point one nine two billion times per second.

Speaker 5 (40:59):
And it doesn't depend on the frequency of the light,
or it does.

Speaker 1 (41:02):
It definitely depends on the frequency of the light. If
the frequency of the light is not correct, then it
won't even absorb it, right, it won't happen.

Speaker 5 (41:08):
Oh, but then don't you need to make that frequency
super precise?

Speaker 1 (41:12):
Yeah, exactly, And this is one source of uncertainty in
these clocks, right, making those accurate. And you can measure
these things, like you build two independent ones, you can
see how their counts drift relative to each other. And
that's how you measure the accuracy of clocks. In general.
There's no absolute standard by which you can tell like, oh,
this clock is off or that clock is off. You
just build a few of them and you measure them
relative to each other. And this is something that we

(41:34):
know well enough. We know how to design the mean
of the physics and the engineering that you can build
these things so that atomic clocks in independent locations agree
to zero point three nanoseconds per day. It's really very
incredibly precise.

Speaker 5 (41:48):
WHOA, so what are you measuring? How are you measuring
whether these electrons are going up and down?

Speaker 1 (41:53):
When the electron goes back down. It emits radiation, right,
and so you can gather that as well.

Speaker 5 (41:57):
Like it shoots off light like an a blink.

Speaker 1 (41:59):
Basically exactly little flash.

Speaker 5 (42:01):
All right. So then, and you're saying you can build
these things now to be the size of a toaster
or a microwave oven.

Speaker 1 (42:09):
A quantum toaster. They have them now and they've deployed
them out in space. They actually built the Deep Space
Atomic Clock Mission and they sent an atomic clock out
into space to see, like, hey, can we operate one
of these things out in space? And you might wonder
like is this just a bunch of nerds trying to
do something that seems cool? Yes, is always the answer.

Speaker 5 (42:28):
Like can we shoot a microwave into space and will
it still heat up my burrito? My season Burritoah? Is
that the challenge?

Speaker 1 (42:35):
That's the challenge. But also if we want to do
things like navigate in space, navigation needs timing. You need
to know like how long you're going in one direction.
If you want to do dead reckoning, you want to
know where you are. Timing is absolutely crucial. Or if
you want to use like nearby pulsars to triangulate your position,
I have whole episode about how that works. You also
need very accurate timing so you can measure the time

(42:58):
between the pulses. So this was like a technological challenge
that's going to lay the groundwork for all sorts of
cool innovations, and this was totally successful in this deep
space atomic clock mission.

Speaker 5 (43:08):
Well, let's get into how you would actually use these
and how the timing might tell you where dark matter
is within our Solar system and maybe even within the Earth.
So let's dig into that. But first, let's take another
quick break.

Speaker 2 (43:26):
With the United Explorer Card. Earn fifty thousand bonus miles,
then head for places unseen and destinations unknown. Wherever your
journey takes you, you'll enjoy remarkable rewards, including a free
checked bag and two times the miles on every United purchase.
You'll also receive two times the miles on dining and
at hotels, so every experience is even more rewarding. Plus,

(43:46):
when you fly United, you can look forward to United
Club access with two United Club one time passes per year.
Become a United Explorer Card member today and take off
on more trips so you can take in once in
a lifetime experiences everywhere you travel, visit the explorercard dot
com to apply today. Cards issued by JP Morgan Chase
Bank NA member FDIC subject to credit approval offers subject

(44:08):
to change. Terms apply.

Speaker 1 (44:10):
When you pop a piece of cheese into your mouth
or enjoy a rich spoonful of Greek yogurt, you're probably
not thinking about the environmental impact of each and every bite,
But the people in the dairy industry are. US Dairy
has set themselves some ambitious sustainability goals, including being greenhouse
gas neutral by twenty to fifty. That's why they're working
hard every day to find new ways to reduce waste,

(44:31):
conserve natural resources, and drive down greenhouse gas emissions. Take water,
for example, most dairy farms reuse water up to four
times the same water cools the milk, cleans equipment, washes
the barn, and irrigates the crops. How is US dairy
tackling greenhouse gases? Many farms use anaerobic digestors that turn
the methane from maneuver into renewable energy that can power farms, towns,

(44:52):
and electric cars. So the next time you grab a
slice of pizza or lick an ice cream cone, know
that dairy farmers and processors around the country are using
the Lake Edith practices and innovations to provide the nutrienttents
dairy products we love with less of an impact. Visit
usdairy dot com slash sustainability to learn more.

Speaker 3 (45:10):
There are children, friends, and families walking, riding on pass
and roads every day. Remember they're real people with loved
ones who need them to get home safely. Protect our
cyclists and pedestrians because they're people too. Go safely California
from the California Office of Traffic Safety and caltrans.

Speaker 10 (45:24):
Looking for the perfect night's sleep Brooklyn Betting. As you
covered with over twenty five years in the mattress industry,
Brooklyn Betting combines top tier comfort and quality without the
hefty price tag. Every mattress is designed and assembled by
master craftsmen, ensuring expert oversight. Plus, they have a factory
in Arizona and ship conveniently to your front doorstep for free.

(45:48):
Choose from a range of firmness levels, heights and dimensions,
including non traditional sizes to find the perfect mattress fit
for your needs. And with a one hundred and twenty
nights sleep trial on all mattresses, you can rest easy
knowing you're making the right choice. Visit Brooklynbetting dot com
to learn more and take advantage of their twenty five
percent off sitewide sale going on now.

Speaker 6 (46:11):
Ryan Seacrest here. When you have a busy schedule, it's
important to maximize your downtime. One of the best ways
to do that is by going to Chumbuckcasino dot com.
Chumbuck Casino has all your favorite social casino games like spin, slots, bingo,
and Solitaire that you can play for free for a
chance to redeem some serious prizes. So hop on to
Chumbucasino dot com now and live the Chumba life sponsored

(46:34):
by Chumpa Casino. No purchase necessary. VGW group void. We're
prohibited by Law eighteen plus. Terms and conditions apply.

Speaker 5 (46:50):
All right. We're talking about using a microwave stuck inside
of a microwave to the tech dark matter so you
can win a Tierra for being the prettiest scientist.

Speaker 1 (47:00):
Exactly does it take longer to heat up your burrito
when there's dark matter around?

Speaker 5 (47:04):
So the idea is that you take these atomic or
basically an atomic clock, which is a quantum clock. But
it seems like the most popular ones use atoms, and
so you shrink them down to the size of a
toaster or microwave, and then you shoot them in space.
And then how does that help you measure dark matter?

Speaker 1 (47:20):
Well, there were a bunch of physicists who thought, Okay,
this is cool because now we not only have all
some super precise atomic clocks, but now we have them
spread out through the Solar system, like in principle the
way we like scent devices near the Sun with a
Parker solar probe. People are like, what if we built
a bunch of these things and we spread them out
in the Solar system? Could they give us a picture
of where the dark matter is in the Solar system?

(47:42):
If they operate differently when there's dark matter around, like
if they're sensitive to the dark matter density, Like if
your atomic clock gets off if it drifts when there's
more or less dark matter around, than having a bunch
of these atomic clocks spread out through the Solar system
could give you a picture for where in the Solar
System the dark matter is.

Speaker 5 (48:02):
But I guess what's the mechanism by which dark matter
would affect the timing of these clocks.

Speaker 1 (48:07):
Yeah, so mostly it wouldn't For many theories of dark matter.
Dark matter is just some whimp. It's a massive particle
that only interacts gravitationally, and so it has essentially no
effect on these clocks except for gravitational time dilation. We
know the areas with greater mass have more curvature, and
a curvature causes time dilation, but that would be very,
very difficult to measure even with these quantum clocks.

Speaker 5 (48:29):
But wait, why would it be difficult.

Speaker 1 (48:30):
You can measure gravitational time dilation with quantum clocks, and
we've done that. You can do it on the surface
of the Earth, for example, and you can put a
quantum clock one meter above another one and you can
see the difference between them because one of them is
deeper in the curvature than the other. Super duper awesome,
but that's because the Earth has a huge amount of
gravity and this significant curvature. Here. Dark matter doesn't contribute

(48:52):
significantly to the curvature because it's pretty spread out. And
we would already know if dark matter wasn't pretty spread out,
because we would have seen deviations and like Jupiter's orbit
and whatever. So in principle you can, but we don't
think it's going to be very sensitive. If you had
a lot of quantum clocks and there were much more sensitive,
then you could probably detect dark matter local density variations

(49:13):
using that principle.

Speaker 5 (49:14):
Meaning these clocks would tick at a different frequency depending
on how close it was to big sources of mass
or even light sources of mass, because that's just how
relativity works.

Speaker 1 (49:25):
Yeah, that's how relativity works. Remember, in relativity, it is
two kinds of time dilation. One is based on speed.
If you see a clock moving quickly, then you see
it ticking slowly, and that's very confusing because it's relative,
and so it depends on two observers. But there's another
kind of time dilation, gravitational, which is absolute. It just
says anybody in curature their clock is going to tick slowly,

(49:46):
no matter who's looking at it, and everybody's going to
agree about whose clock is ticking slowly. So that's very
powerful and that's something you can use to measure just
like how much stuff is there in general, because clocks
tick slower near stuff. Really kind of awesome feature of.

Speaker 5 (50:01):
The universe, meaning like if I had two of these
atomic clocks and one of them is out there in
the middle of empty space, and the other one is
near a big blob of dark matter. The one near
the blob of dark matter would take slower.

Speaker 1 (50:12):
Right, Yeah, that's exactly right.

Speaker 5 (50:14):
And so you might like start them out in the
same spot. But then after being for a while and
two different spots, one near the dark matter, and you
brun them back, you would see that one of them
take more ticks than the other.

Speaker 1 (50:26):
Yeah. And so now imagine like a grid, you have
a quantum clock every ten meters in the solar system, right,
you start them all out at the same time, and
then you monitor it, and by measuring the difference in
that number of ticks after a year on your reference clock,
the one that's hanging out with you, you can tell
where stuff is in the solar system.

Speaker 5 (50:43):
Like which spots in the solar system have slower time.

Speaker 1 (50:47):
Yes, exactly, because slower time means more matter, more curvature,
more energy density.

Speaker 5 (50:52):
Really, I guess, on top of what you already know
about the Solar system right like right now, even if
we didn't have dark matter, a clock near the Sun
would takes lower than a clock here exactly.

Speaker 1 (51:03):
And we've done some basic version of this, as I
said earlier, if a few clocks on Earth at different altitudes.
Those are different distances from the matter of the Earth,
and the ones closer do ticks more slowly, And satellites
up in space their clocks tick faster than atomic clocks
here on the surface of the Earth, And you've got
to take that new account famously when you're doing GPS,
et cetera.

Speaker 5 (51:23):
But you're saying, we're not going to be using this effect,
this time dilation from relativity to measure dark matter. Dark
matter is just too weak.

Speaker 1 (51:31):
Dark matter is too weak, and we think it's not
cluppy enough to really detect that, though it would be
super awesome. There's a special kind of dark matter which
might give much larger effects, which would be much easier
to discover. And this is a theory called fuzzy dark matter.

Speaker 5 (51:45):
Sounds fuzzy. But wait, so you're saying, like this idea
of using atomic clocks to measure dark matter would only
work for a certain theoretical meaning guessie type of dark matter,
which we don't know whether it's true or not, or
exist or not.

Speaker 4 (52:02):
Mm hmmm.

Speaker 5 (52:03):
So this is a huge sources in white scheme that
you don't really know if it's going to work.

Speaker 1 (52:08):
You know, you were talking about nomenclature and now you're
using the words guess and scheme, you know, really kind
of undermine the credibility of science. But you know, this
is good faith stuff. This is like, hey, what if
dark matter is this other weird particular thing, how could
we see that? And yet it'd be best if we
had experiments which could detect any kind of dark matter,
But you know, there might be kinds of dark matter
which we could only detect in certain ways or easier

(52:30):
to spot in some ways. And so it's good to
be creative and think about how we could detect specific
kinds of dark matter as well, even though we don't
know what dark matter is. And if this theory is at.

Speaker 5 (52:40):
All correct, well, I'm just trying to understand the scheme.
So are you saying there's a theoretical kind of dark
matter called fuzzy dark matter? So what is it?

Speaker 4 (52:49):
So?

Speaker 1 (52:49):
Fuzzy dark matter suggests that maybe dark matter isn't very massive,
like some people suggest that dark matter could be like
one hundred GeV like the mass of a w or
a z boson, like one hundred times the mass of
a proton, a pretty hefty particle, almost as massive as
a Higgs. That's sort of the classic strategy, and there's
reasons for that. There's something called the Wimp miracle. Check

(53:11):
on our podcast about that, which argues strongly that dark
matter should be around one hundred gv based on how
much of it there is in the universe. But people
are like, well, maybe that's all wrong, and there's an
assumption there that's wrong. What if dark matter is super
duper light, like a trilliance the mass of an electron.
So now there's an enormous number of these dark matter particles,
so many more than you could even imagine, because you

(53:33):
have to somehow make like a big fraction of the
mass of the universe out of particles that are a
tiny fraction in the mass of the electron, which is
already very very light.

Speaker 5 (53:42):
Well, first of all, I think this whole podcast is
a Wimp miracle, Daniel. But I think you're saying, like
this version of dark matter, instead of being maybe marble
sized particles, they're like super tiny BB sized particles, And
some of that makes it fuzzier.

Speaker 1 (53:57):
Yeah, it makes it fuzzier because if they're very very
low mass, then their wavelengths are more spread out. Some
of these things can have a wavelength like the size
of the galaxy.

Speaker 5 (54:06):
What do you mean a wavelength.

Speaker 1 (54:07):
The wavelength of a particle is like the distance on
which these quantum interference effects appear, and so you can
calculate this quantity. It's called the Debrogely wavelength. You'll see
wave like effects for a particle when you interact over
these kinds of distances, and that's the wavelength of a particle.

Speaker 5 (54:24):
Meaning sort of like the size of it.

Speaker 1 (54:25):
Kind of right, sort of, Yeah, it's when it stops
acting like a blob like a particle and starts acting
more like a wave. Things that have wavelike behaviors. Really
it's always acting like a wave. It's just that when
you zoom out you can approximate it as a particle.

Speaker 5 (54:38):
Because they have low mass. What's the relationship between having
low mass and being having big wavelengths.

Speaker 1 (54:44):
Well, the wavelength depends on your momentum and your mass.
So lower mass just means a larger wavelength because it's
really like a ratio between the momentum and the mass.
When things have a lot of kinetic energy relative to
their mass, they act more like light because light is
pure kinetic energy. Have very small amounts of energy relative
to their mass their stationary so they act more like

(55:04):
bits of sand like particles. And so it's just sort
of a rough way to understand where that transition happens.

Speaker 5 (55:11):
Okay, so then if dark matter is this kind of
fuzzy kind of dark matter, you're saying that each particle
would be super super light, and it would also have
huge variations in their size. That's what you mean by fuzzy.
It's like they might be some of them might be
super big and somewhere might be super small.

Speaker 1 (55:26):
Yeah, well, the wavelengths could be very very large, which
means they can interact over long distances. The fascinating thing
is that in simulations of this dark matter, it predicts
like a mini halo of dark matter in our Solar system,
essentially that this stuff would be clumped up in and
near the Sun. That most of the dark matter in
the Solar System might be like clumped up near the Sun.

(55:46):
It might be like hiding in the Sun.

Speaker 5 (55:49):
And if it wasn't this kind of fuzzy dark matter,
it wouldn't.

Speaker 1 (55:52):
Now, this kind of fuzzy dark matter is the kind
we think would clump up like a halo near the Sun.

Speaker 5 (55:57):
And the other kinds wouldn't.

Speaker 1 (55:58):
Yeah, the other kinds wouldn't. As I mean, I've heard
of other theories of dark matter clumping in the Sun.
There's all sorts of theories, but this particular one tends
to make a halo near the Sun and would affect
the operation of quantum clocks because of its special fuzziness.
It can also slightly interact with electrons through sort of
like a back door in quantum mechanics, which would change

(56:19):
the way a quantum clock operates. It's like it changes
the electrons' mass and how it responds to photons because
of oscillations in this fuzzy dark matter field, and so
effectively it changes the frequency of these clocks. And so
you can detect in principle whether you're near a dense
blob of this ultra light dark matter by looking at

(56:39):
a quantum clock and counting its ticks very carefully. And
this would be a bigger effect than the effect we
talked about earlier, the gravitational curvature.

Speaker 5 (56:46):
But I thought that dark matter couldn't interact with regular
matter only through it could only do it through gravity.

Speaker 1 (56:52):
Yeah, it could only do it through gravity in general,
But this one takes a back door through the Higgs field.
It like interacts with the Higgs field and it changes
how the Higgs field works. And so near the presence
of this ultra light dark matter, electrons effectively have a
different mass.

Speaker 5 (57:06):
But I guess if that was true, wouldn't we see
it affect regular matter on a larger scale.

Speaker 1 (57:11):
You would see it happen, but it's a subtle effect,
and so you need to be near a dense clump
of it. So the idea is, take something that's very
very sensitive to the electron mass, like a quantum clock,
and try to put it near a dense clump of
this special ultra light dark matter, maybe near the Sun.
So that's the idea is, like launch a bunch of
quantum clocks, have them orbit near the Sun, and look

(57:31):
for deviations in their timekeeping and see if that's evidence
for ultra light dark matter interfering with the masses of
the electrons in these quantum clocks.

Speaker 5 (57:40):
We mean that you would maybe like throw a bunch
of the sun, have them kind of form a half
ring around the Sun to see if time changes there,
sort of like a giant tirra.

Speaker 1 (57:50):
Like a giant tr a quantum cosmic tiara.

Speaker 5 (57:54):
All right, but I guess which one would you be proving.
Would you be proving that dark matter is fuzzy or
would you be proved that it's there? Or are they
both related?

Speaker 1 (58:03):
They're both related.

Speaker 4 (58:04):
Though.

Speaker 1 (58:04):
You know, if we saw this thing, there would instantly
be like fifty other theories to explain it as well.
It probably wouldn't be a unique prediction of this kind
of dark matter. Theories are very very clever people, and
they'll always come up with another way to explain the
data that we're seeing. But it's cool because it's a
prediction that this theory makes and we go out and
we see it. That's really fascinating, and then we can

(58:24):
think about ways to distinguish all the different ideas that
might also explain this kind of observation. It would just
be cool to see something different. Currently, all of our
dark matter experiments basically see nothing. It would be cool
to have a signal somewhere.

Speaker 5 (58:39):
So you're thinking, hey, let's put up a bunch of
microways in space and see if at sticks exactly.

Speaker 1 (58:43):
Let's see if one burrito is a little bit colder
than another.

Speaker 5 (58:46):
All right, Well, an interesting idea for how we could
maybe possibly crack sort of a theoretical version of one
of the biggest mysteries in the universe.

Speaker 1 (58:56):
That's right. Physicists are being very creative and trying to
come up with new theories of dark matter and new
ways to discover them, including using super duper sets in
and quantum clocks distributed through the solar system, which also
would just be fun to do.

Speaker 5 (59:09):
You just want to parade, Daniel, I.

Speaker 1 (59:11):
Just want a tiara? Is that too much to ask?

Speaker 5 (59:16):
How about we just buy you a tiara?

Speaker 1 (59:18):
Is it made of dark matter? Are you using your bitcoin?

Speaker 5 (59:20):
It can be, but in any way that you want.
But if it saves tax dollars billions of dollars, you know,
it would be a pretty good investment.

Speaker 1 (59:27):
Yeah, there we go. That was my scheme the whole time.

Speaker 5 (59:30):
Yeah, to get us to buy you a tiara without
actually having to run in a beauty contest.

Speaker 1 (59:36):
I'm busted.

Speaker 5 (59:38):
Well, you are the most beautiful podcaster with a show
called Daniel Jorge is playing the universe. So whose name
is Daniels?

Speaker 1 (59:45):
I'll take very highly qualified compliments, thank you.

Speaker 5 (59:49):
It's a very specific tiara based on a very theoretical
model of the.

Speaker 1 (59:55):
Universe fuzzy compliments from Warhead.

Speaker 5 (59:57):
All right, well, we hope you enjoyed that. Thanks for
joining us. See you next time.

Speaker 1 (01:00:06):
For more science and curiosity, come find us on social
media where we answer questions and post videos. We're on Twitter, Disport, 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,

(01:00:26):
or wherever you listen to your favorite shows. When you
pop a piece of cheese into your mouth, you're probably
not thinking about the environmental impact. But the people in
the dairy industry are. That's why they're working hard every
day to find new ways to reduce waste, conserve natural resources,
and drive down greenhouse gas emissions. House US Dairy tackling

(01:00:49):
greenhouse gases. Many farms use anaerobic digestors to turn the
methane from manure into renewable energy that can power farms, towns,
and electric cars. As dairy dot COM's Last Sustainability to
learn more.

Speaker 2 (01:01:03):
As a United Explorer card member, you can earn fifty
thousand bonus miles plus look forward to extraordinary travel rewards,
including a free checked bag, two times the miles on
United purchases and two times the miles on dining and
at hotels. Become an explorer and seek out unforgettable places
while enjoying rewards everywhere you travel. Cards issued by JP
Morgan Chase Bank NA Member FDIC subject to credit approval

(01:01:26):
offer subject to change. Terms apply.

Speaker 3 (01:01:29):
There are children, friends, and families walking, riding on paths
and roads every day. Remember they're real people with loved
ones who need them to get home safely. Protect our
cyclists and pedestrians because they're people too. Go safely, California
from the California Office of Traffic Safety and Caltrans.

Speaker 1 (01:01:43):
You slept through your alarm, missed the train and your
breakfast sandwich. Ugh cool, sounds like you could use some luck.

Speaker 11 (01:01:52):
I'm Victoria Cash and Lucky Land is where people go
every day to get lucky. At Lucky Land, you can
play over one hundred casino style games for free for
your chance to redeem some serious prizes. Go to Lucky
landslots dot com and get lucky today. No purchase necessary.
BGW Group Cooid We're prohibited by Law eighteen plus terms

(01:02:12):
and conditions apply.

Speaker 8 (01:02:13):
Odu is business management made so simple a kid could
explain it.

Speaker 4 (01:02:17):
Sometimes business software can't talk to other programs, but Odo,
funny word, has every program from CRM to HR to
accounting in one platform. It should cost a lot, but
it doesn't. So you should use Odu because they save
you money.

Speaker 5 (01:02:35):
Odo makes a lot of sense but doesn't cost a
lot of sense.

Speaker 1 (01:02:38):
Sign up now at odu dot com.

Speaker 4 (01:02:40):
That's odoo dot com.

Speaker 1 (01:02:42):
Good job.

Speaker 11 (01:02:43):
Thanks,