WEBVTT - Could quantum clocks detect dark matter?

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<v Speaker 1>Hey, Daniel, if you were dark Matter, where would you hide?

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<v Speaker 2>I wouldn't hide. If I was dark matter, I would

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<v Speaker 2>totally parade myself in front of all the scientists in

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<v Speaker 2>the galaxy.

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<v Speaker 1>Ooh, a parade. You mean like a pageant.

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<v Speaker 2>Queen, Yeah, something like that. You know, just don't be

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<v Speaker 2>so shy.

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<v Speaker 1>Well, if it turns out you are dark matter, we'll

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<v Speaker 1>definitely throw you a parade. But so far, it seems

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<v Speaker 1>like dark matter is kind of reclusive, right, It's kind

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<v Speaker 1>of shy, So maybe it is hiding. What would be

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<v Speaker 1>some good spots for it to hide it?

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<v Speaker 2>Well, if dark matter doesn't want a tiara and it's

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<v Speaker 2>hiding somewhere, then I don't know where it would hide.

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<v Speaker 2>I mean, if I knew, I would go and look

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<v Speaker 2>for it there.

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<v Speaker 1>What if it's somewhere kind of.

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<v Speaker 2>Obvious, like what like right behind me?

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<v Speaker 1>Yeah, or right in front of you, or right on

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<v Speaker 1>TV and the Matter universe contest, that.

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<v Speaker 2>Would be a great twist ending for the m Knight

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<v Speaker 2>Shamanlan version of this story.

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<v Speaker 1>Well, man, do you think he knows I see dark Matter?

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<v Speaker 3>Hi?

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<v Speaker 1>I'm Jorge Mack, cartoonists and the author of Ollor's Great

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<v Speaker 1>Big Universe.

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<v Speaker 4>Hi.

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<v Speaker 2>I'm Daniel. I'm a particle physicist, and I wish I

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<v Speaker 2>had a dark matter Tiara.

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<v Speaker 1>Oh, but it wouldn't be very shiny or bright. It

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<v Speaker 1>would be dark, So what's the point. Also, when it

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<v Speaker 1>had just fall through your head, it.

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<v Speaker 2>Would be hard to wear, but it'd be like the greatest,

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<v Speaker 2>most amazing piece of jewelry.

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<v Speaker 1>Ever, how would you even keep it in your house?

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<v Speaker 2>These are just like engineering details, you know. Once I've

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<v Speaker 2>solved the physics of a dark matter Tiara, I'll just

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<v Speaker 2>pass that off to the engineers.

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<v Speaker 1>This is just all part of your dream to be

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<v Speaker 1>the universe's doctor Universe.

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<v Speaker 2>I would like a little bit of bling. Yeah, you know,

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<v Speaker 2>physics blining would be nice. I'm not going to win

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<v Speaker 2>a Nobel Prize anytime soon, So dark matter Tira sounds good.

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<v Speaker 1>I see. I see. You could just say you have

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<v Speaker 1>a dark matter Tierra, and they nobody would be able

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<v Speaker 1>to see it, or feel it or detect it. They

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<v Speaker 1>would just have to believe you.

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<v Speaker 2>I need evidence, man, That's what science is all about.

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<v Speaker 2>You got to have data.

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<v Speaker 1>I don't think those beauty contests depend on data very much.

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<v Speaker 2>But I'm trying to win a science contest.

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<v Speaker 1>But anyway's welcome. Dark podcast Daniel and Jorge Explain the Universe,

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<v Speaker 1>a production of iHeartRadio in which.

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<v Speaker 2>We enter you in the greatest science contest of all time,

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<v Speaker 2>the quest to understand the nature of the universe. What

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<v Speaker 2>is it, what's in it, what's it made out of?

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<v Speaker 2>How does it all work. We think these questions are

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<v Speaker 2>deep and fundamental parts of being a human being in

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<v Speaker 2>this cosmos, and unraveling these questions is a joy that

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<v Speaker 2>everybody should share. So on this podcast we take those

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<v Speaker 2>questions apart and try to share our answers and our

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<v Speaker 2>ignorance with you.

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<v Speaker 1>That's right, because science is the greatest beauty contest in

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<v Speaker 1>the universe, where the goal is to discover the beauty

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<v Speaker 1>of how this universe is put together, how it works,

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<v Speaker 1>and what is our place in it.

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<v Speaker 2>Over the last fifty one hundred years, we've developed a

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<v Speaker 2>pretty good sense for what's in the universe. We know

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<v Speaker 2>about stars and galaxies and all the bright and shiny

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<v Speaker 2>stuff that's out there in the universe, and we've also

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<v Speaker 2>figured out that there's a lot of the universe that

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<v Speaker 2>we can't see directly using our senses or any of

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<v Speaker 2>the forces that we've discovered except for gravity. We know

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<v Speaker 2>that a huge chunk of the stuff that's out there

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<v Speaker 2>in the universe is invisible. It's intangible, which makes it

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<v Speaker 2>very hard to discover and to figure out how to

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<v Speaker 2>make it into a tiara.

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<v Speaker 1>Yeah, because it turns out that a pretty good understanding

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<v Speaker 1>of the universe only covers about uh five percent of

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<v Speaker 1>what we know is out there. The rest, the ninety

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<v Speaker 1>five percent of the universe that we know is there,

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<v Speaker 1>we have no idea what it is or how it works.

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<v Speaker 2>That sounds like a good title for a book.

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<v Speaker 1>Yeah, I think we rode One Daniel, which is available

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<v Speaker 1>for a sale everywhere.

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<v Speaker 2>That's right. The kind of stuff that you and I

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<v Speaker 2>are made out of, atoms specifically, or what physicists called baryons,

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<v Speaker 2>only makes up five percent of the energy budget in

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<v Speaker 2>the universe. There's another twenty five twenty seven percent that's

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<v Speaker 2>dark matter, some kind of stuff that we know is matter.

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<v Speaker 2>We know it's out there, but we don't know what

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<v Speaker 2>it is, and we only have a very rough sense

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<v Speaker 2>of even where it is around us. The rest of

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<v Speaker 2>the universe is something we call dark energy, which is

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<v Speaker 2>contributing to the accelerating expansion of the universe and we

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<v Speaker 2>have even less clue about what makes that up.

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<v Speaker 1>Yeah, there's a lot we don't know, and it seems

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<v Speaker 1>like these are maybe the defining mysteries of our times

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<v Speaker 1>is to figure out what the universe is actually made

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<v Speaker 1>out of, given that what we're made out of counts

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<v Speaker 1>is so little of it.

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<v Speaker 2>Yeah, you're right. And in the last few decades there's

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<v Speaker 2>been a huge program of people looking for dark matter.

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<v Speaker 2>We've talked on the podcast about trying to make dark

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<v Speaker 2>matter in the laboratory by smashing particles together. We're searching

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<v Speaker 2>for the dark matter wind. We might be floating through

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<v Speaker 2>with very sensitive underground facilities looking for an individual piece

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<v Speaker 2>of dark matter to bump into liquid xenon, for example,

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<v Speaker 2>or maybe evidence of dark matter annihilating itself in the

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<v Speaker 2>center of the galaxy. But so far, none of these

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<v Speaker 2>experiments have found dark matter, which means we've got to

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<v Speaker 2>get creative about other ways to maybe detect this most

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<v Speaker 2>important or at least most common kind of matter in

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<v Speaker 2>the universe.

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<v Speaker 1>So to be on the podcast, we'll be tackling the

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<v Speaker 1>question could quantum clocks detect dark matter and how many

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<v Speaker 1>jargon words can we fit into one podcast title.

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<v Speaker 2>I know it does sound like buzzword sound, you know, like,

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<v Speaker 2>could we use AI generated crypto bitcoin to detect dark matter?

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<v Speaker 1>You mean quantum nanomtter Yes, exactly, quantum nanomtter tierras.

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<v Speaker 2>Wow, I like quantum nano matter. I go use that

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<v Speaker 2>in a proposal.

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<v Speaker 1>That's good, I said it first, I said at first, Daniel. Also,

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<v Speaker 1>it's probably already on sale on Amazon. There's probably some

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<v Speaker 1>product out there with that name.

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<v Speaker 2>So yeah, but you didn't say ching tm after it,

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<v Speaker 2>so I can use it.

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<v Speaker 1>No, you don't have to.

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<v Speaker 2>What I gotta brush up on my podcast property law.

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<v Speaker 1>Yeah, you better or else I'm gonna see you for

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<v Speaker 1>nano dollars for nano bitcoins, you know what?

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<v Speaker 2>Or hey, you can have all of my nano bitcoins.

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<v Speaker 1>What's the price of bitcoins these days?

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<v Speaker 2>Nano bitcoins zero? Yeah, doesn't exist.

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<v Speaker 1>But anyways, it's kind of an intriguing title. Could quantum

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<v Speaker 1>clocks detect dark matter? And quantum clocks sounds like it

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<v Speaker 1>does sound like something you could buy an off of Amazon.

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<v Speaker 1>Did you check to see if it's something you can

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<v Speaker 1>just get next day?

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<v Speaker 3>Oh?

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<v Speaker 2>Yeah, it turns out Amazon will sell you something. It

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<v Speaker 2>calls a quantum clock, like a quantum entanglement led wall clock,

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<v Speaker 2>but none of these things are actually quantum clocks the

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<v Speaker 2>way that we understand them.

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<v Speaker 1>Well, technically, isn't everything a quantum something? Well, I mean

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<v Speaker 1>not everything, but you know, the five percent that we

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<v Speaker 1>know about in the universe is in it all quantum technically,

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<v Speaker 1>like this is a quantum podcast.

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<v Speaker 2>I mean, that's a really interesting philosophical question and not

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<v Speaker 2>one that we really have an answer to, because on

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<v Speaker 2>one hand, you're right that everything is made out of

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<v Speaker 2>quantum particle, so isn't the whole universe quantum? On the

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<v Speaker 2>other hand, we know that when you zoom out things

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<v Speaker 2>behave by different rules. We call that classical. We don't

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<v Speaker 2>really understand why there is that transition, but there definitely

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<v Speaker 2>is a transition. So to call everything quantum is either

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<v Speaker 2>to say that look classical is just big zoomed out quantum,

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<v Speaker 2>or is to say that clackical doesn't really matter, which

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<v Speaker 2>doesn't really sit well with me. Or what if I

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<v Speaker 2>have no class, then you probably have a lot of

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<v Speaker 2>big coin.

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<v Speaker 1>Then I'm not going to win any beauty contest. I

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<v Speaker 1>have poise, but just no class.

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<v Speaker 2>Yeah, exactly, But you know, for example, a clock that

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<v Speaker 2>just works on mechanical parts would also work in the

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<v Speaker 2>universe where quantum mechanics didn't rule the microscopic because it's

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<v Speaker 2>not sensitive to those microscopic details, and so that wouldn't

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<v Speaker 2>be a quantum clock, for example, like a pendulum clock

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<v Speaker 2>or an old fashioned Swiss gear based clock.

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<v Speaker 1>A discussion about new mankla Sure that's my favorite.

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<v Speaker 2>Hey, you brought it up, But.

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<v Speaker 1>Anyways, it's a kind of an interesting question and so

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<v Speaker 1>we'll dig into it. But as usually, we were wondering

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<v Speaker 1>how many people out there had thought about putting the

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<v Speaker 1>concepts of dark matter and quantum and clocks all together

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<v Speaker 1>in one sentence.

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<v Speaker 2>So thanks very much to everybody who participates in this

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<v Speaker 2>segment of the podcast. We love that you volunteer, We

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<v Speaker 2>love hearing your thoughts, and we love sharing your voice

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<v Speaker 2>with all of the other listeners. Please chime in if

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<v Speaker 2>you'd like, writeing me two questions at Danielanjorge dot com

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<v Speaker 2>and you can't participate.

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<v Speaker 1>So think about it for a second. Do you think

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<v Speaker 1>quantum clocks can use to detect dark matter? Here's what

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<v Speaker 1>people had to say.

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<v Speaker 4>I've heard of a quantum clock, but I'm not sure

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<v Speaker 4>how it would be able to detect dark matter anymore

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<v Speaker 4>than a regular clock could. I guess maybe even with

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<v Speaker 4>a regular clock, you could send it out into space,

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<v Speaker 4>and if it hits a huge clump of dark matter

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<v Speaker 4>and therefore gravity, maybe we could learn that there's a

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<v Speaker 4>big well of gravity out in some location that we

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<v Speaker 4>otherwise couldn't detect.

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<v Speaker 1>So sure, I suppose it's possible, but I have no

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<v Speaker 1>clue how it would Maybe something to do with entanglement.

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<v Speaker 3>Since you're asking, the answer is probably yes, but maybe

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<v Speaker 3>still theoretical. I would think you'd have to use the

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<v Speaker 3>idea of measuring light passing through an area of more

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<v Speaker 3>density that's possibly dark matter that causes curvature of space

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<v Speaker 3>and also time dilation. How to do that, I'm not sure.

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<v Speaker 2>Since we don't possess a quantum clock, it doesn't seem

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<v Speaker 2>unreasonable to suggest that a non existent clock cannot detect

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<v Speaker 2>dark matter.

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<v Speaker 1>All right, it's pretty uh intense answers here. I feel

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<v Speaker 1>like it's something that some of the listeners have I

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<v Speaker 1>heard about before. Did you pull your professor colleagues this time?

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<v Speaker 2>No, these are our listeners online. You know there's some

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<v Speaker 2>good answers here about entanglement and light passing through areas

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<v Speaker 2>with dark matter density in them, and just in general

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<v Speaker 2>sense that this is a hard problem.

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<v Speaker 1>Maybe you should ask a bunch of beauty queens next

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<v Speaker 1>time we're making one of the standard questions in a

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<v Speaker 1>beauty pageant. Forget howdy, how would you save the world

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<v Speaker 1>or how would you know make things better? What do

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<v Speaker 1>you think about quantum plock?

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<v Speaker 2>Well, where is the dark matter? Yeah, I'd love to

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<v Speaker 2>hear that answer in the beauty pageant.

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<v Speaker 1>Not that it couldn't happen, of course, no, absolutely. All right, Well,

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<v Speaker 1>let's dig into this intriguing question of whether dark matter

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<v Speaker 1>can be detected by quantum clocks, and let's start with

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<v Speaker 1>the basics, Daniel, what do we know about dark matter?

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<v Speaker 2>So there's a lot that we do and do not

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<v Speaker 2>know about dark matter. So let's start with what we

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<v Speaker 2>do know. We know that it's out there, and we

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<v Speaker 2>know that it's here as well. We know that dark

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<v Speaker 2>matter is something that exists in the universe. And then

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<v Speaker 2>it's matter. We know that because we see its gravity.

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<v Speaker 2>We see it holding galaxies together as they spin. There

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<v Speaker 2>isn't enough gravity from the stars and the gas and

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<v Speaker 2>dust that make up those galaxies to keep the stars

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<v Speaker 2>in place as they swirl around the center of the

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<v Speaker 2>galaxy at very high speeds, and yet they do stay

0:11:23.240 --> 0:11:26.960
<v Speaker 2>in place. Galaxies are mostly not throwing stars out into

0:11:27.000 --> 0:11:29.840
<v Speaker 2>intergalactic space, and so we infer that there must be

0:11:29.880 --> 0:11:33.640
<v Speaker 2>some matter there to hold that galaxy together. But it's

0:11:33.679 --> 0:11:36.480
<v Speaker 2>more than just that one inference, that one fudge factor

0:11:36.520 --> 0:11:39.599
<v Speaker 2>to make that particular equation work. We see evidence for

0:11:39.720 --> 0:11:42.240
<v Speaker 2>dark matter all over the history of the universe, from

0:11:42.280 --> 0:11:45.280
<v Speaker 2>the very first few moments when the early universe plasma

0:11:45.320 --> 0:11:48.640
<v Speaker 2>is slashing around and you have dark matter and normal

0:11:48.679 --> 0:11:52.200
<v Speaker 2>matter and photons all acting very differently and creating different

0:11:52.240 --> 0:11:56.000
<v Speaker 2>slashing patterns. From looking at that slashing in the cosmic

0:11:56.040 --> 0:11:59.280
<v Speaker 2>microwave background radiation, we can figure out that there was

0:11:59.400 --> 0:12:01.839
<v Speaker 2>dark matter, even measure how much of it there is,

0:12:02.200 --> 0:12:04.800
<v Speaker 2>and we can trace the history of dark matter's gravity

0:12:04.800 --> 0:12:07.520
<v Speaker 2>as it shapes the structure formation of the whole universe.

0:12:07.840 --> 0:12:10.440
<v Speaker 2>Why we have galaxies at all this early in the

0:12:10.480 --> 0:12:13.160
<v Speaker 2>history of the universe, and so dark matter is definitely

0:12:13.160 --> 0:12:15.080
<v Speaker 2>out there as a kind of matter, but we don't

0:12:15.120 --> 0:12:18.719
<v Speaker 2>know really what it is or very specifically where it

0:12:18.840 --> 0:12:22.040
<v Speaker 2>is because it's so hard to see since it only

0:12:22.080 --> 0:12:24.760
<v Speaker 2>feels gravity. It doesn't feel any of the other forces

0:12:24.760 --> 0:12:25.640
<v Speaker 2>that we've discovered.

0:12:26.000 --> 0:12:28.640
<v Speaker 1>And we can also sort of see dark matter right like,

0:12:28.679 --> 0:12:30.120
<v Speaker 1>we can see it in the same way that you

0:12:30.120 --> 0:12:32.520
<v Speaker 1>can see a lens or glass lens or example. You

0:12:32.559 --> 0:12:35.200
<v Speaker 1>can see how it distorts the light behind it.

0:12:35.320 --> 0:12:38.559
<v Speaker 2>Right, Yeah, exactly, we can see dark matter through gravity,

0:12:38.600 --> 0:12:41.320
<v Speaker 2>and so that means we can see stuff bending around

0:12:41.400 --> 0:12:44.440
<v Speaker 2>dark matter. We can see it holding galaxies together, and

0:12:44.480 --> 0:12:47.400
<v Speaker 2>that even impacts how light moves in the vicinity of

0:12:47.559 --> 0:12:50.520
<v Speaker 2>dark matter. If you have a big blob of dark

0:12:50.559 --> 0:12:53.680
<v Speaker 2>matter between you and some distant galaxy, for example, the

0:12:53.720 --> 0:12:56.760
<v Speaker 2>photons from that distant galaxy will bend as they move

0:12:56.840 --> 0:13:00.559
<v Speaker 2>through that dark matter, creating apparent distortions in your image.

0:13:00.559 --> 0:13:03.480
<v Speaker 2>You can even sometimes see the same galaxy twice in

0:13:03.520 --> 0:13:07.160
<v Speaker 2>the sky because of this gravitational lensing, and so we

0:13:07.280 --> 0:13:08.760
<v Speaker 2>know that it's out there, and we can use some

0:13:08.880 --> 0:13:11.760
<v Speaker 2>techniques like that to sometimes tell roughly where it is.

0:13:12.440 --> 0:13:15.920
<v Speaker 2>But because dark matter is so weak it's particles only

0:13:15.960 --> 0:13:18.920
<v Speaker 2>feel gravity, we think it's very difficult to figure out

0:13:18.920 --> 0:13:21.840
<v Speaker 2>what exactly is made out of To isolate one piece

0:13:21.960 --> 0:13:24.920
<v Speaker 2>of dark matter, because gravity is so weak that essentially

0:13:25.000 --> 0:13:28.240
<v Speaker 2>a particle's gravity is almost impossible to measure.

0:13:28.400 --> 0:13:30.800
<v Speaker 1>Yeah, and dark matter is also something that's not just

0:13:31.000 --> 0:13:34.200
<v Speaker 1>out there in space. It's sort of like all around us,

0:13:34.280 --> 0:13:36.720
<v Speaker 1>right like it's floating through us right now, sort of

0:13:36.760 --> 0:13:39.160
<v Speaker 1>like the fourth you know, it flows through us, binds

0:13:39.200 --> 0:13:42.720
<v Speaker 1>us all together. It's made out of meti chlorians.

0:13:42.760 --> 0:13:46.880
<v Speaker 2>Perhaps, perhaps, yeah, exactly, you'll only really understand it after

0:13:47.000 --> 0:13:49.680
<v Speaker 2>nine hundred years of study. That's a really good question,

0:13:49.800 --> 0:13:52.480
<v Speaker 2>and that's sort of the central question of this episode

0:13:52.600 --> 0:13:56.040
<v Speaker 2>is exactly where is the dark matter and can we

0:13:56.080 --> 0:13:59.280
<v Speaker 2>find like concentrations of it? Can we map it out?

0:14:00.080 --> 0:14:03.920
<v Speaker 2>Because dark matter is so weakly interacting like only gravity,

0:14:03.960 --> 0:14:06.640
<v Speaker 2>it takes huge amounts of it to feel anything, and

0:14:06.720 --> 0:14:09.160
<v Speaker 2>so that makes it very hard to tell exactly where

0:14:09.200 --> 0:14:11.680
<v Speaker 2>the dark matter is. It might be that it's mostly

0:14:11.720 --> 0:14:14.520
<v Speaker 2>spread out evenly through the galaxy. It might be more

0:14:14.600 --> 0:14:17.760
<v Speaker 2>clumpy than that depends a lot on your particular theory

0:14:17.880 --> 0:14:21.000
<v Speaker 2>of dark matter. Where it exactly is. So it could

0:14:21.080 --> 0:14:23.120
<v Speaker 2>be that we are in a dark matter wind as

0:14:23.160 --> 0:14:25.360
<v Speaker 2>the Earth orbits the Sun and the Sun moves through

0:14:25.400 --> 0:14:28.360
<v Speaker 2>the galaxy. We could also be in a dark matter

0:14:28.480 --> 0:14:31.840
<v Speaker 2>Liss bubble, a bubble of space in which there's comparatively

0:14:31.960 --> 0:14:34.240
<v Speaker 2>little dark matter, or it could be that dark matter

0:14:34.280 --> 0:14:35.800
<v Speaker 2>is fairly dense in our area.

0:14:36.000 --> 0:14:37.240
<v Speaker 1>You know, I have to say every time you say

0:14:37.320 --> 0:14:40.560
<v Speaker 1>dark matter wind, it makes me think of dark.

0:14:40.360 --> 0:14:45.600
<v Speaker 2>Part elevating the discourse every week.

0:14:48.040 --> 0:14:50.800
<v Speaker 1>That's my job. That's why I'm here. Smells all grounded

0:14:51.960 --> 0:14:55.320
<v Speaker 1>or grounded or you know, flat as in fletch winds.

0:14:56.320 --> 0:14:58.440
<v Speaker 1>But anyways, so it's sort of all around this, and

0:14:58.480 --> 0:15:00.600
<v Speaker 1>I guess I'm wondering, like, if it is all around us,

0:15:00.880 --> 0:15:03.280
<v Speaker 1>would we be able to tell, Like, you know, if

0:15:03.360 --> 0:15:05.720
<v Speaker 1>let's say dark matter is floating through the Earth right now,

0:15:06.000 --> 0:15:07.760
<v Speaker 1>or let's say it wasn't, would you be able to

0:15:07.760 --> 0:15:08.480
<v Speaker 1>tell the difference.

0:15:08.720 --> 0:15:11.640
<v Speaker 2>That's exactly what these experiments are trying to measure. And

0:15:11.720 --> 0:15:14.520
<v Speaker 2>to give you a sense of the difficulty the challenge

0:15:14.520 --> 0:15:17.560
<v Speaker 2>of this, think about like why we didn't discover dark

0:15:17.600 --> 0:15:21.040
<v Speaker 2>matter earlier. Just in studying how our Solar system moves.

0:15:21.400 --> 0:15:24.360
<v Speaker 2>We have now very precise measurements of the orbit of

0:15:24.440 --> 0:15:26.960
<v Speaker 2>Jupiter and Mars and all the planets and all the

0:15:27.000 --> 0:15:30.240
<v Speaker 2>little pieces of the Solar System as they orbit the Sun.

0:15:30.600 --> 0:15:32.320
<v Speaker 2>You might think, hey, if dark matter is here in

0:15:32.360 --> 0:15:35.240
<v Speaker 2>our Solar system and it has gravity, wouldn't it change

0:15:35.280 --> 0:15:37.680
<v Speaker 2>the way those things orbit? Shouldn't we be able to

0:15:37.760 --> 0:15:39.960
<v Speaker 2>detect it? But because we think dark matter might be

0:15:40.200 --> 0:15:44.040
<v Speaker 2>spread very thin, probably there isn't that much dark matter

0:15:44.160 --> 0:15:46.760
<v Speaker 2>in the vicinity of our solar system. So even those

0:15:46.920 --> 0:15:49.920
<v Speaker 2>very very precise measurements, you know, like knowing the motion

0:15:50.040 --> 0:15:53.880
<v Speaker 2>of Jupiter to meters or centimeters, can't detect dark matter

0:15:54.240 --> 0:15:56.480
<v Speaker 2>because it would be very thin and very spread out,

0:15:56.480 --> 0:15:59.640
<v Speaker 2>and mostly we think homogeneous, which in the end doesn't

0:15:59.640 --> 0:16:02.160
<v Speaker 2>give much much gravitational pull on the objects in the

0:16:02.160 --> 0:16:05.880
<v Speaker 2>solar system. So it takes a very specialized, highly sensitive

0:16:05.920 --> 0:16:08.480
<v Speaker 2>device to be able to detect this dark matter.

0:16:08.680 --> 0:16:10.480
<v Speaker 1>Yeah, and then don't we say once like, if you

0:16:10.520 --> 0:16:13.280
<v Speaker 1>take all the dark matter that is potentially floating through

0:16:13.280 --> 0:16:15.720
<v Speaker 1>the Earth right now, it would only weigh about as

0:16:15.800 --> 0:16:17.880
<v Speaker 1>much as a squirrel or something like that.

0:16:18.160 --> 0:16:21.160
<v Speaker 2>Yeah, exactly, though that's very speculative, right. That assumes that

0:16:21.280 --> 0:16:24.800
<v Speaker 2>dark matter is essentially equally spread out in our galaxy,

0:16:24.880 --> 0:16:27.800
<v Speaker 2>which we don't believe is true. But if you assume

0:16:27.920 --> 0:16:31.160
<v Speaker 2>that there is, then we know our galaxy, for example,

0:16:31.360 --> 0:16:34.880
<v Speaker 2>is ninety five percent dark matter. That means for every

0:16:35.000 --> 0:16:38.000
<v Speaker 2>kilogram of matter made out of atoms like hydrogen and

0:16:38.000 --> 0:16:41.680
<v Speaker 2>helium or whatever, there's nineteen kilograms of matter made out

0:16:41.680 --> 0:16:44.600
<v Speaker 2>of whatever dark matter is made out of, And so

0:16:44.720 --> 0:16:47.880
<v Speaker 2>it's like nineteen to one in our galaxy.

0:16:47.520 --> 0:16:50.400
<v Speaker 1>Which sounds like a lot, but I guess also galaxies

0:16:50.520 --> 0:16:53.880
<v Speaker 1>kind of very empty mostly, right, Like it's probably like

0:16:53.960 --> 0:16:55.400
<v Speaker 1>ninety nine percent empty.

0:16:55.240 --> 0:16:58.240
<v Speaker 2>Yeah, exactly. Now, normal matter clumps up a lot, right

0:16:58.680 --> 0:17:01.720
<v Speaker 2>like the Sun is an extraord ordinarily dense collection of

0:17:01.760 --> 0:17:04.960
<v Speaker 2>normal matter. Normal matter is not spread evenly through the galaxy.

0:17:05.320 --> 0:17:07.680
<v Speaker 2>But if you take dark matter and spread it evenly

0:17:07.720 --> 0:17:11.160
<v Speaker 2>through the galaxy, you get a pretty small density. It's

0:17:11.240 --> 0:17:14.960
<v Speaker 2>like ten to the twenty six kilograms per cubic light year,

0:17:15.160 --> 0:17:18.520
<v Speaker 2>which is a huge volume, which means it's like ten

0:17:18.560 --> 0:17:22.560
<v Speaker 2>to the negative twenty two kilograms per cubic meter. So

0:17:22.600 --> 0:17:24.359
<v Speaker 2>then if you add up all the cubic meters in

0:17:24.440 --> 0:17:27.119
<v Speaker 2>the Earth, that adds up to about two thirds of

0:17:27.160 --> 0:17:30.760
<v Speaker 2>a kilogram of dark matter inside the volume of the Earth. Again,

0:17:30.840 --> 0:17:34.400
<v Speaker 2>assuming that dark matter is evenly spread throughout the galaxy,

0:17:34.440 --> 0:17:36.560
<v Speaker 2>which it probably isn't, but it might be.

0:17:36.600 --> 0:17:40.200
<v Speaker 1>Roughly, which is about the size or mass of a squirrel.

0:17:40.359 --> 0:17:43.520
<v Speaker 2>Yeah, exactly, so one squirrel of dark matter inside the

0:17:43.560 --> 0:17:45.840
<v Speaker 2>volume of the Earth compared to you know, the many,

0:17:45.880 --> 0:17:48.919
<v Speaker 2>many millions and billions of kilograms of normal matter inside

0:17:48.920 --> 0:17:51.960
<v Speaker 2>the volume of the Earth. That sounds the importance of clumping, right,

0:17:51.960 --> 0:17:54.720
<v Speaker 2>Because normal matter clumps together, its gravity is much more

0:17:54.800 --> 0:17:58.080
<v Speaker 2>powerful in our local neighborhood than dark matter. Even though

0:17:58.160 --> 0:18:01.600
<v Speaker 2>dark matter outweighs normal matter by nineteen to one, if

0:18:01.600 --> 0:18:04.280
<v Speaker 2>it's much more thinly spread out, the local effects of

0:18:04.280 --> 0:18:06.080
<v Speaker 2>its gravity are much harder to detect.

0:18:06.240 --> 0:18:08.520
<v Speaker 1>I think maybe what you're saying is that dark matter,

0:18:09.119 --> 0:18:12.399
<v Speaker 1>in terms of the universe scale, it mostly hangs out

0:18:12.480 --> 0:18:14.400
<v Speaker 1>in galaxies. Like you don't see a lot of dark

0:18:14.440 --> 0:18:16.960
<v Speaker 1>matter floating out there on its own between galaxies.

0:18:17.040 --> 0:18:18.960
<v Speaker 2>Yeah, we can do really precise measurements of where dark

0:18:19.000 --> 0:18:21.680
<v Speaker 2>matter is on the galaxy scale, because galaxies are really

0:18:21.720 --> 0:18:24.600
<v Speaker 2>really big. If you can tell how galaxies are orbiting

0:18:24.640 --> 0:18:26.920
<v Speaker 2>around each other, just the way we can tell how

0:18:26.960 --> 0:18:30.159
<v Speaker 2>stars are moving through the galaxy, so enormous clumps of

0:18:30.240 --> 0:18:33.080
<v Speaker 2>dark matter, absolutely we can measure their gravity. But when

0:18:33.119 --> 0:18:35.320
<v Speaker 2>you zoom in in a really fine grained way and

0:18:35.359 --> 0:18:37.920
<v Speaker 2>want to say, hey, is there a moon sized blob

0:18:37.960 --> 0:18:40.280
<v Speaker 2>of dark matter anywhere in our solar system. That's a

0:18:40.280 --> 0:18:41.359
<v Speaker 2>tough question to answer.

0:18:41.440 --> 0:18:44.119
<v Speaker 1>So then within the galaxy, you're saying, like, there's a

0:18:44.119 --> 0:18:46.200
<v Speaker 1>lot of dark matter within our galaxy. Ninety five percent

0:18:46.200 --> 0:18:48.480
<v Speaker 1>of the mass of our galaxy is dark matter. And

0:18:48.520 --> 0:18:50.600
<v Speaker 1>what does it look like. Does it look like, you know,

0:18:50.880 --> 0:18:53.680
<v Speaker 1>an intense, dense ball of dark matter in the middle.

0:18:54.240 --> 0:18:57.280
<v Speaker 1>Is it evenly distributed? And also like our galaxy looks

0:18:57.320 --> 0:18:59.359
<v Speaker 1>like a disc, sort of like a flat disk. Is

0:18:59.480 --> 0:19:01.320
<v Speaker 1>dark matter also shaped like a flat disk?

0:19:01.520 --> 0:19:03.840
<v Speaker 2>So we have the best answers the more we zoom out,

0:19:03.880 --> 0:19:06.520
<v Speaker 2>and then as we zoom in, things get literally fuzzy.

0:19:06.560 --> 0:19:08.879
<v Speaker 2>But on the scale of the galaxy, we have some ideas.

0:19:09.160 --> 0:19:11.320
<v Speaker 2>We think that dark matter is like a big halo.

0:19:11.640 --> 0:19:14.280
<v Speaker 2>So imagine the visible galaxy right at the edge of

0:19:14.320 --> 0:19:17.400
<v Speaker 2>the stars. Dark matter is a big halo that goes

0:19:17.440 --> 0:19:21.320
<v Speaker 2>out beyond the visible stars, and it's bigger and fuzzier.

0:19:21.320 --> 0:19:23.639
<v Speaker 2>It hasn't collapsed the way normal matter has because it

0:19:23.720 --> 0:19:26.200
<v Speaker 2>just doesn't clump right. In order to clump, things need

0:19:26.280 --> 0:19:29.119
<v Speaker 2>other kinds of interaction other than gravity. Like if you

0:19:29.160 --> 0:19:31.960
<v Speaker 2>have two dark matter particles, they attract each other gravitationally

0:19:32.000 --> 0:19:33.960
<v Speaker 2>and then just pass right through each other. They're just

0:19:34.000 --> 0:19:37.000
<v Speaker 2>gonna zig and zag back and forth, oscillate forever. They're

0:19:37.000 --> 0:19:38.840
<v Speaker 2>not going to clump together. To do that. You need

0:19:38.920 --> 0:19:42.000
<v Speaker 2>like electromagnetism or the strong force or something that wants

0:19:42.080 --> 0:19:44.920
<v Speaker 2>to grab onto each other. So dark matter stays a

0:19:44.960 --> 0:19:48.280
<v Speaker 2>big puffy halo, and the galaxy is sort of embedded

0:19:48.359 --> 0:19:51.040
<v Speaker 2>in that halo. And that's not a coincidence. Right. The

0:19:51.080 --> 0:19:54.440
<v Speaker 2>reason the galaxy exists is because of a big dark

0:19:54.480 --> 0:19:58.360
<v Speaker 2>matter blob there that's gathered together all the hydrogen helium

0:19:58.400 --> 0:20:01.879
<v Speaker 2>gravitationally and may it into a galaxy. It's the reason

0:20:01.920 --> 0:20:03.240
<v Speaker 2>we have stars, et cetera.

0:20:03.520 --> 0:20:06.160
<v Speaker 1>Now, when you say like halo, you don't actually mean

0:20:06.200 --> 0:20:08.480
<v Speaker 1>like an angel's halo that looks like a ring. You

0:20:08.520 --> 0:20:10.200
<v Speaker 1>actually mean just like a blob, right.

0:20:10.240 --> 0:20:13.440
<v Speaker 2>Yeah, exactly, like a big fuzzy blob that extends out

0:20:13.480 --> 0:20:16.399
<v Speaker 2>further along the disc and then further above and below

0:20:16.480 --> 0:20:19.320
<v Speaker 2>the disc. But even that we know already is not

0:20:19.440 --> 0:20:20.359
<v Speaker 2>evenly distributed.

0:20:20.400 --> 0:20:22.560
<v Speaker 1>Is it like football shaped? Is it you? Is it

0:20:22.640 --> 0:20:24.320
<v Speaker 1>kind of flat or is it a perfect sphere?

0:20:24.600 --> 0:20:27.080
<v Speaker 2>It's more like a hockey puck, right, It's flat, but

0:20:27.200 --> 0:20:29.200
<v Speaker 2>not as flat as the galaxy. Itself.

0:20:29.280 --> 0:20:30.160
<v Speaker 1>What made it flat?

0:20:30.280 --> 0:20:32.400
<v Speaker 2>Yeah, maybe a hockey puck is the wrong analogy. It's

0:20:32.400 --> 0:20:35.640
<v Speaker 2>not quite that flat. It's more like a big ellipsoid.

0:20:35.840 --> 0:20:37.560
<v Speaker 1>You mean like a slightly squished ball.

0:20:37.880 --> 0:20:42.080
<v Speaker 2>Yeah, exactly, It's like a big basketball that somebody's sitting

0:20:42.119 --> 0:20:42.720
<v Speaker 2>on or something.

0:20:42.880 --> 0:20:45.240
<v Speaker 1>All right, Well, let's get a little bit more into

0:20:45.400 --> 0:20:47.879
<v Speaker 1>the details of what we know about dark matter. How

0:20:47.960 --> 0:20:49.879
<v Speaker 1>much of it can we see? How much can we

0:20:49.960 --> 0:20:53.960
<v Speaker 1>discern about what it's doing in our universe? And we'll

0:20:54.000 --> 0:20:56.359
<v Speaker 1>answer the question of whether you can use a quantum

0:20:56.400 --> 0:21:00.880
<v Speaker 1>clock from Amazon dot com to detect it. So we'll

0:21:00.920 --> 0:21:03.639
<v Speaker 1>get to those questions, but first's take at a quick break.

0:21:16.240 --> 0:21:18.480
<v Speaker 1>All right, we're asking the question can you use quantum

0:21:18.480 --> 0:21:22.119
<v Speaker 1>clocks to detect dark matter? And we've been recapping a

0:21:22.160 --> 0:21:25.119
<v Speaker 1>little bit about what we know about dark matter, Daniel.

0:21:25.320 --> 0:21:27.560
<v Speaker 1>How much of the details of it can we see?

0:21:27.720 --> 0:21:31.160
<v Speaker 2>Not really very much. We have this sense of a big,

0:21:31.280 --> 0:21:35.960
<v Speaker 2>fuzzy halo that surrounds the galaxy, and we can also

0:21:36.080 --> 0:21:39.280
<v Speaker 2>measure the density as a function of distance from the center.

0:21:39.440 --> 0:21:41.879
<v Speaker 2>So if you're a star, for example, orbiting the center

0:21:41.880 --> 0:21:45.200
<v Speaker 2>of the galaxy, the speed at which you orbit depends

0:21:45.320 --> 0:21:48.680
<v Speaker 2>on the force that's holding you in that orbit. So

0:21:48.680 --> 0:21:51.760
<v Speaker 2>the stronger the force, the faster you can go, or

0:21:51.800 --> 0:21:53.560
<v Speaker 2>the faster you can go, the stronger the force that's

0:21:53.680 --> 0:21:56.320
<v Speaker 2>needed to hold you in that orbit. So by measuring

0:21:56.320 --> 0:21:59.200
<v Speaker 2>the speed of a given star, we can essentially measure

0:21:59.240 --> 0:22:01.600
<v Speaker 2>the mass of all all that stuff that's holding on

0:22:01.760 --> 0:22:03.679
<v Speaker 2>to that star. So then if you look at stars

0:22:03.680 --> 0:22:07.040
<v Speaker 2>at different distances from the center, you can basically map

0:22:07.119 --> 0:22:10.199
<v Speaker 2>out the density of stuff in the galaxy as you

0:22:10.280 --> 0:22:13.159
<v Speaker 2>go further and closer to the center of the galaxy.

0:22:13.480 --> 0:22:16.440
<v Speaker 1>Like if dark matter was super condensed in the middle

0:22:16.440 --> 0:22:19.520
<v Speaker 1>of the galaxy, then the stars in the galaxy would

0:22:19.520 --> 0:22:22.480
<v Speaker 1>be rotating a certain way. Or if the dark matter

0:22:22.560 --> 0:22:25.119
<v Speaker 1>was more spread out, then the stars in the galaxy

0:22:25.160 --> 0:22:26.840
<v Speaker 1>would be rotating in a different way.

0:22:27.000 --> 0:22:29.800
<v Speaker 2>Yeah, exactly, if all the dark matter in the galaxy

0:22:29.920 --> 0:22:32.119
<v Speaker 2>was at the center, then everything would act in a

0:22:32.119 --> 0:22:34.080
<v Speaker 2>certain way, would just go like one over are squared.

0:22:34.080 --> 0:22:35.960
<v Speaker 2>It's sort of like the way the Solar system orbits

0:22:36.000 --> 0:22:38.040
<v Speaker 2>the Sun. But if you take some of that mass

0:22:38.040 --> 0:22:40.840
<v Speaker 2>and you spread it out through the galaxy instead, then

0:22:40.880 --> 0:22:43.240
<v Speaker 2>the dark matter that's further out than a given star

0:22:43.320 --> 0:22:46.520
<v Speaker 2>doesn't affect its orbit because its gravity all cancels out,

0:22:46.760 --> 0:22:49.960
<v Speaker 2>so that changes the rotation speed of those stars. And

0:22:49.960 --> 0:22:52.879
<v Speaker 2>that's in fact how we first discover dark matter was

0:22:52.880 --> 0:22:55.679
<v Speaker 2>by looking at these rotation speeds of stars around the

0:22:55.680 --> 0:22:58.400
<v Speaker 2>center of the galaxy and seeing that we couldn't explain

0:22:58.440 --> 0:23:00.720
<v Speaker 2>it by mapping all the mass from the stars and

0:23:00.760 --> 0:23:02.600
<v Speaker 2>the gas and the dust. And that's exactly how you

0:23:02.640 --> 0:23:05.199
<v Speaker 2>can tell where you need to add more mass to

0:23:05.280 --> 0:23:08.040
<v Speaker 2>explain these rotation speeds. It's not just like, hey, add

0:23:08.040 --> 0:23:09.920
<v Speaker 2>a big blob at the center. You need to add

0:23:09.920 --> 0:23:12.000
<v Speaker 2>some of the center and also some further out and

0:23:12.080 --> 0:23:15.800
<v Speaker 2>some further out, and so precise measurements of those velocities

0:23:15.960 --> 0:23:18.240
<v Speaker 2>give you a fairly accurate picture of where the dark

0:23:18.280 --> 0:23:21.200
<v Speaker 2>matter is in the galaxy. And it's not evenly spread out.

0:23:21.400 --> 0:23:24.280
<v Speaker 2>It's more densely clumped at the center, which is something you'd.

0:23:24.119 --> 0:23:27.560
<v Speaker 1>Expect because it is affected by gravity, right, It.

0:23:27.480 --> 0:23:29.800
<v Speaker 2>Is, in the end affected by gravity, and so it's

0:23:29.840 --> 0:23:33.320
<v Speaker 2>pulled itself together. And the whole reason that this exists

0:23:33.880 --> 0:23:37.600
<v Speaker 2>is because of some like early universe perturbation where you

0:23:37.640 --> 0:23:40.600
<v Speaker 2>had a denser blob of dark matter that created this

0:23:40.640 --> 0:23:43.719
<v Speaker 2>whole well gathered together the other dark matter and created

0:23:43.720 --> 0:23:46.440
<v Speaker 2>this over density which then pulled in hydrogen, helium and

0:23:46.480 --> 0:23:49.600
<v Speaker 2>whatever was around to make a galaxy. So it's a

0:23:49.600 --> 0:23:52.080
<v Speaker 2>little bit denser at the center. Though it's not very

0:23:52.080 --> 0:23:56.240
<v Speaker 2>well understood, like if we do calculations simulations to describe

0:23:56.359 --> 0:23:58.440
<v Speaker 2>what we think should happen. If you have a bunch

0:23:58.480 --> 0:24:00.359
<v Speaker 2>of dark matter and you'll give it a few billion

0:24:00.440 --> 0:24:02.960
<v Speaker 2>years to fall together and to form some structure. It

0:24:03.000 --> 0:24:06.280
<v Speaker 2>describes what astronomers call a cusp, which means like a

0:24:06.320 --> 0:24:08.320
<v Speaker 2>point of high density of the center and then very

0:24:08.359 --> 0:24:10.840
<v Speaker 2>steeply falling, should like drop off quickly. But if you

0:24:10.840 --> 0:24:14.680
<v Speaker 2>go out and measure the actual distributions of stars velocities,

0:24:15.000 --> 0:24:17.360
<v Speaker 2>you see something that looks like a bigger core. It's

0:24:17.400 --> 0:24:20.080
<v Speaker 2>not like it's pointing near the center. It's more spread

0:24:20.119 --> 0:24:23.679
<v Speaker 2>out in the inner galaxy. It's like flatter, and so

0:24:23.800 --> 0:24:25.800
<v Speaker 2>this is not something we understand very well. And it

0:24:25.840 --> 0:24:27.840
<v Speaker 2>also gives you a sense of like the scale of

0:24:27.880 --> 0:24:30.000
<v Speaker 2>which we can figure this stuff out. We're talking about

0:24:30.000 --> 0:24:33.080
<v Speaker 2>over light years distances, right, we're not resolving dark matter

0:24:33.119 --> 0:24:37.280
<v Speaker 2>in meters or even in aus with very very coarse

0:24:37.359 --> 0:24:40.200
<v Speaker 2>ways to measure where the dark matter is. Again, because

0:24:40.200 --> 0:24:41.720
<v Speaker 2>its gravity is so weak.

0:24:41.520 --> 0:24:44.080
<v Speaker 1>Are you saying, like the beginning of the universe, dark

0:24:44.080 --> 0:24:46.840
<v Speaker 1>matter was more evenly spread out, Like you know, all

0:24:46.840 --> 0:24:49.640
<v Speaker 1>those light years of empty space between us and Andromeda

0:24:49.680 --> 0:24:52.159
<v Speaker 1>and other galaxies was all filled with dark matter, and

0:24:52.160 --> 0:24:54.639
<v Speaker 1>then it all collapsed into certain clusters.

0:24:54.800 --> 0:24:57.639
<v Speaker 2>Yeah, it definitely gathered itself together. The early universe had

0:24:57.680 --> 0:25:01.400
<v Speaker 2>initial density fluctuations, and that's a whole big question about

0:25:01.440 --> 0:25:05.000
<v Speaker 2>where exactly that came from. And then those seated gravity

0:25:05.040 --> 0:25:08.439
<v Speaker 2>to pull things together. So gravity does form structure, but

0:25:08.520 --> 0:25:11.040
<v Speaker 2>it takes time. And so yeah, dark matter was more

0:25:11.080 --> 0:25:13.000
<v Speaker 2>spread out and now it's less spread out.

0:25:13.040 --> 0:25:14.960
<v Speaker 1>Why would dark matter stay stuck together?

0:25:15.160 --> 0:25:17.520
<v Speaker 2>Well, it's not that dark matter is sticking together. It's

0:25:17.520 --> 0:25:19.560
<v Speaker 2>not like it's bonded to itself. And again we don't

0:25:19.560 --> 0:25:22.119
<v Speaker 2>really know because we don't have a microscopic picture of

0:25:22.240 --> 0:25:24.920
<v Speaker 2>the dark matter. But I think you're asking, like why

0:25:24.920 --> 0:25:27.959
<v Speaker 2>does dark matter form even gravitational structures? Like why does

0:25:28.000 --> 0:25:30.520
<v Speaker 2>it get more dense in some places and then in others?

0:25:30.560 --> 0:25:31.359
<v Speaker 2>Is that what you're asking?

0:25:31.560 --> 0:25:33.679
<v Speaker 1>Yeah, Like I'm imagining at the beginning of the universe

0:25:33.680 --> 0:25:36.480
<v Speaker 1>there's a bit of dark matter that was you know,

0:25:36.640 --> 0:25:38.720
<v Speaker 1>let's say ten light years away, and then it got

0:25:38.720 --> 0:25:41.800
<v Speaker 1>attracted to our galaxy, so it flew over here. But

0:25:41.920 --> 0:25:44.280
<v Speaker 1>then why didn't it just keep flying to the other side.

0:25:44.440 --> 0:25:46.880
<v Speaker 2>Yeah, so as that distant piece of dark matter approaches

0:25:46.920 --> 0:25:51.120
<v Speaker 2>the galaxy, it gains velocity. Right, it's exchanging gravitational potential

0:25:51.200 --> 0:25:54.159
<v Speaker 2>energy for kinetic energy. And then you're imagining, like the

0:25:54.200 --> 0:25:56.080
<v Speaker 2>way a ball rolls down a valley, why doesn't it

0:25:56.160 --> 0:25:58.880
<v Speaker 2>roll back up the other side? And it will, yes,

0:25:58.920 --> 0:26:01.840
<v Speaker 2>but then it comes back right, And so gravity in

0:26:01.880 --> 0:26:05.399
<v Speaker 2>the end is organizing something. There's the second piece to that,

0:26:05.480 --> 0:26:08.680
<v Speaker 2>which is that it doesn't completely grow back up the

0:26:08.720 --> 0:26:12.520
<v Speaker 2>other side. You know, anything that's accelerating is emitting gravitational

0:26:12.640 --> 0:26:16.040
<v Speaker 2>radiation for example. So the reason, for example, two black

0:26:16.080 --> 0:26:19.720
<v Speaker 2>holes orbiting each other will eventually spiral in and collapse

0:26:20.080 --> 0:26:23.040
<v Speaker 2>is that they're emitting gravitational energy. So none of these

0:26:23.040 --> 0:26:25.960
<v Speaker 2>things are really stable. So over long periods of time,

0:26:26.200 --> 0:26:30.359
<v Speaker 2>even without inelastic interactions like electromagnetism or whatever, these things

0:26:30.400 --> 0:26:34.760
<v Speaker 2>will form very large structures and they will gradually collapse

0:26:34.840 --> 0:26:36.240
<v Speaker 2>due to gravitational radiation.

0:26:36.600 --> 0:26:38.879
<v Speaker 1>All right, so we kind of have a fuzzy picture

0:26:38.920 --> 0:26:41.520
<v Speaker 1>of where it is in the universe. So now the

0:26:41.600 --> 0:26:44.360
<v Speaker 1>question of the episode is can we use quantum clocks

0:26:44.680 --> 0:26:48.080
<v Speaker 1>to detect dark matter? How do quantum clocks fit into this?

0:26:48.359 --> 0:26:51.000
<v Speaker 2>So quantum clocks might give us a sense for where

0:26:51.000 --> 0:26:53.639
<v Speaker 2>the dark matter is if we can find a place

0:26:53.680 --> 0:26:56.399
<v Speaker 2>where it's like clumpy, if we can find a place

0:26:56.560 --> 0:26:59.720
<v Speaker 2>in our solar system where it's like gathered together for

0:26:59.800 --> 0:27:02.520
<v Speaker 2>some reason. And that would be really cool because not

0:27:02.560 --> 0:27:05.040
<v Speaker 2>only would it help us detect what dark matter is,

0:27:05.240 --> 0:27:07.919
<v Speaker 2>but it would help us understand where it is. It's

0:27:07.960 --> 0:27:09.960
<v Speaker 2>a really deep mystery, I think, not just because we

0:27:10.040 --> 0:27:12.000
<v Speaker 2>want to understand dark matter, but because we want like

0:27:12.040 --> 0:27:15.080
<v Speaker 2>a map. You know, humans are visual creatures. We want

0:27:15.080 --> 0:27:17.159
<v Speaker 2>to know like where the stuff is, and just not

0:27:17.400 --> 0:27:20.679
<v Speaker 2>knowing where dark matter is in the universe really bugs me.

0:27:20.760 --> 0:27:22.800
<v Speaker 2>So I would love to know where it is and

0:27:23.280 --> 0:27:26.959
<v Speaker 2>understanding its map on a finer scale would be really helpful.

0:27:27.000 --> 0:27:29.520
<v Speaker 2>And quantum clocks might be able to help us map

0:27:29.680 --> 0:27:31.840
<v Speaker 2>where dark matter is if we can send them out

0:27:31.920 --> 0:27:35.720
<v Speaker 2>into space and if they're sensitive to dark matter, if

0:27:35.720 --> 0:27:38.760
<v Speaker 2>their operation changes as they pass through dark matter.

0:27:38.840 --> 0:27:40.359
<v Speaker 1>Okay, I think you're saying that you know, at the

0:27:40.359 --> 0:27:43.359
<v Speaker 1>galaxy level, we know that it looks like a big blob.

0:27:43.400 --> 0:27:45.879
<v Speaker 1>It's sort of like a switchball. It's sort of more

0:27:45.920 --> 0:27:48.200
<v Speaker 1>intense or more dense in the center of the galaxy.

0:27:48.400 --> 0:27:50.520
<v Speaker 1>But I think maybe you're saying, can we know in

0:27:50.600 --> 0:27:55.400
<v Speaker 1>finer detail what it looks like between stars within the galaxy,

0:27:55.520 --> 0:27:58.240
<v Speaker 1>like is it clumpy, is it chunky, or is it

0:27:58.280 --> 0:28:01.000
<v Speaker 1>like peanut butter or smooth exactly?

0:28:01.119 --> 0:28:03.840
<v Speaker 2>And people have tackled this problem in the past, Like

0:28:04.000 --> 0:28:06.920
<v Speaker 2>people use the technique you mentioned gravitation lensing to look

0:28:06.960 --> 0:28:10.320
<v Speaker 2>for blobs of dark matter, and that works and it's powerful,

0:28:10.480 --> 0:28:13.480
<v Speaker 2>but only if you have like a really nice galaxy

0:28:13.720 --> 0:28:16.320
<v Speaker 2>behind the blob of dark matter that can show you

0:28:16.400 --> 0:28:18.520
<v Speaker 2>that it's there, So that tells us a little bit

0:28:18.520 --> 0:28:20.960
<v Speaker 2>about the dark matter density. But there aren't like galaxies

0:28:21.000 --> 0:28:22.960
<v Speaker 2>in all the right places to like X ray the

0:28:23.000 --> 0:28:25.159
<v Speaker 2>whole Solar system and figure out where it is, And

0:28:25.160 --> 0:28:27.199
<v Speaker 2>that technique isn't always powerful enough. You need like a

0:28:27.200 --> 0:28:29.919
<v Speaker 2>really big blob of dark matter. Another technique people have

0:28:30.040 --> 0:28:33.600
<v Speaker 2>used is to look for dwarf galaxies. Essentially, our galaxy

0:28:33.680 --> 0:28:36.640
<v Speaker 2>is formed by the combination of lots of galaxies, right,

0:28:36.840 --> 0:28:39.240
<v Speaker 2>we think galaxies formed kind of small and then grew

0:28:39.280 --> 0:28:42.600
<v Speaker 2>together with all sorts of absorptions and collisions. That means

0:28:42.600 --> 0:28:46.360
<v Speaker 2>that our galaxy has other, like many galaxies embedded within it.

0:28:46.760 --> 0:28:49.400
<v Speaker 2>Some of these we call dwarf galaxies because they're small

0:28:49.600 --> 0:28:52.440
<v Speaker 2>and we think they're like very high dark matter density.

0:28:52.480 --> 0:28:55.480
<v Speaker 2>They're very few stars, and so we can look at

0:28:55.480 --> 0:28:58.000
<v Speaker 2>the motion of the stars inside those little galaxies to

0:28:58.040 --> 0:29:00.760
<v Speaker 2>get sensors for like where those blobs are. But we

0:29:00.800 --> 0:29:02.800
<v Speaker 2>don't have a great way to like X ray the

0:29:02.840 --> 0:29:05.360
<v Speaker 2>Solar System and figure out like where is the dark

0:29:05.360 --> 0:29:07.959
<v Speaker 2>matter in our Solar system? Is it hanging out by Jupiter?

0:29:08.240 --> 0:29:11.080
<v Speaker 2>Is it spread evenly like peanut butter? What's going on?

0:29:11.560 --> 0:29:14.160
<v Speaker 1>You want to know it's distribution at the Solar system

0:29:14.200 --> 0:29:15.000
<v Speaker 1>scale exactly.

0:29:15.040 --> 0:29:16.680
<v Speaker 2>That's what I want to do. And I read a

0:29:16.680 --> 0:29:19.320
<v Speaker 2>recent paper which was very clever, which is looking at

0:29:19.360 --> 0:29:22.600
<v Speaker 2>asteroids and trying to track asteroid trajectories and see if

0:29:22.640 --> 0:29:26.200
<v Speaker 2>like tiny little deviations in the trajectory of asteroids or

0:29:26.200 --> 0:29:29.520
<v Speaker 2>comets as they move through the Solar System could reveal

0:29:29.600 --> 0:29:32.040
<v Speaker 2>the presence of dark matter. It's very difficult to do

0:29:32.080 --> 0:29:34.720
<v Speaker 2>because if dark matter is evenly spread out or only

0:29:34.720 --> 0:29:37.600
<v Speaker 2>a little bit clumpy, that be basically no effect on

0:29:37.720 --> 0:29:40.160
<v Speaker 2>those asteroids. But it's the kind of thing that we're

0:29:40.200 --> 0:29:42.440
<v Speaker 2>just on the verge of being able to potentially do

0:29:42.560 --> 0:29:45.760
<v Speaker 2>now that we have better measurements and better computational tools

0:29:45.800 --> 0:29:49.720
<v Speaker 2>to try to like infer this information from really specific measurements.

0:29:49.760 --> 0:29:51.840
<v Speaker 1>All right, So then how would you use a quantum

0:29:51.880 --> 0:29:53.560
<v Speaker 1>clock to de teg dark matter?

0:29:53.680 --> 0:29:55.880
<v Speaker 2>So when we talk about a quantum clock, really what

0:29:55.880 --> 0:29:59.040
<v Speaker 2>we mean is something which is based on fundamental quantum

0:29:59.080 --> 0:30:01.800
<v Speaker 2>mechanical principles. And you know, it sounds fancy, but even

0:30:01.840 --> 0:30:04.880
<v Speaker 2>just like an atomic clock is a quantum clock. An

0:30:04.880 --> 0:30:07.520
<v Speaker 2>atomic clock is something that looks at like the oscillation

0:30:07.600 --> 0:30:10.560
<v Speaker 2>of electron between two energy levels and a caesium atom,

0:30:10.840 --> 0:30:14.920
<v Speaker 2>which is a very precise, very very regular process that

0:30:15.000 --> 0:30:18.240
<v Speaker 2>we can use essentially to tell how time has passed.

0:30:18.840 --> 0:30:22.360
<v Speaker 2>And so on Earth, we have extraordinarily precise atomic clocks

0:30:22.400 --> 0:30:25.040
<v Speaker 2>which now set the standard and in fact define what

0:30:25.080 --> 0:30:27.240
<v Speaker 2>we mean by a second. A second used to have

0:30:27.280 --> 0:30:30.040
<v Speaker 2>a different definition, but now a second is defined as

0:30:30.120 --> 0:30:32.840
<v Speaker 2>like a certain number of cycles of a specific kind

0:30:32.880 --> 0:30:37.280
<v Speaker 2>of atom. That's literally how we measure time now, and

0:30:37.320 --> 0:30:38.680
<v Speaker 2>so it's the standard.

0:30:39.040 --> 0:30:41.040
<v Speaker 1>But it's like the minute, like it used to be

0:30:41.120 --> 0:30:43.680
<v Speaker 1>like a minute with sixty seconds, but now people say, oh,

0:30:43.720 --> 0:30:46.640
<v Speaker 1>it's been a minute to really mean something totally different.

0:30:50.600 --> 0:30:55.400
<v Speaker 2>Yes, it's just like that exactly. And we call it

0:30:55.440 --> 0:30:58.160
<v Speaker 2>a quantum clock because this really is a quantum process.

0:30:58.200 --> 0:31:01.479
<v Speaker 2>We're talking about quantum particles, an electron, there's an atom.

0:31:01.680 --> 0:31:04.680
<v Speaker 2>The electron is moving in the potential well of the atom,

0:31:04.800 --> 0:31:08.120
<v Speaker 2>so it's interacting electromagnetically with the nucleus, and the way

0:31:08.200 --> 0:31:10.760
<v Speaker 2>that it's moving, the way it oscillates between energy levels,

0:31:11.000 --> 0:31:14.160
<v Speaker 2>is completely controlled by quantum processes. This is not a

0:31:14.200 --> 0:31:16.760
<v Speaker 2>clock that you could have in a perfectly classical universe.

0:31:17.000 --> 0:31:19.360
<v Speaker 2>You know, if we lived in a universe where electrons

0:31:19.400 --> 0:31:21.880
<v Speaker 2>really were tiny little balls that went to orbits and

0:31:21.880 --> 0:31:25.000
<v Speaker 2>had smooth classical paths the way planets do, then this

0:31:25.080 --> 0:31:27.760
<v Speaker 2>clock could not exist. And so that's when we meet

0:31:27.800 --> 0:31:28.880
<v Speaker 2>by quantum clock.

0:31:29.120 --> 0:31:31.239
<v Speaker 1>But I guess, if it's a quantum clock, doesn't it

0:31:31.280 --> 0:31:34.640
<v Speaker 1>have a certain amount of uncertainty to it or unknowability?

0:31:34.880 --> 0:31:38.360
<v Speaker 1>How can it be precise? If there's the Heisenberg uncertainty principle.

0:31:39.640 --> 0:31:42.960
<v Speaker 2>Yeah, you're right, there's no absolutely precise quantum clock. But

0:31:43.160 --> 0:31:45.600
<v Speaker 2>this is about as regular as it gets. And amazingly,

0:31:45.680 --> 0:31:49.200
<v Speaker 2>these quantum clocks are more precise than mechanical clocks, which

0:31:49.200 --> 0:31:51.960
<v Speaker 2>of course also have uncertainty in them, because no mechanical

0:31:52.000 --> 0:31:55.120
<v Speaker 2>device is perfectly created, right, And so this is as

0:31:55.160 --> 0:31:57.520
<v Speaker 2>accurate as they've been able to make them, and recently

0:31:57.600 --> 0:32:01.000
<v Speaker 2>they've been even able to make them small and transportable.

0:32:01.240 --> 0:32:03.400
<v Speaker 2>You might think of an atomic clock as like some

0:32:03.560 --> 0:32:06.880
<v Speaker 2>huge device in the basement of a laboratory in Colorado

0:32:07.160 --> 0:32:09.600
<v Speaker 2>that weighs like ten tons and fills a room. But

0:32:09.680 --> 0:32:11.920
<v Speaker 2>actually these things can be made quite small.

0:32:12.200 --> 0:32:14.760
<v Speaker 1>So a quantum clock is really just an atomic clock,

0:32:14.880 --> 0:32:17.280
<v Speaker 1>or is there another kind that doesn't use atoms?

0:32:17.320 --> 0:32:19.560
<v Speaker 2>There's no atomic clock that's not a quantum clock. So

0:32:19.640 --> 0:32:22.360
<v Speaker 2>quantum clock is just a fancier sounding name for atomic clock.

0:32:22.440 --> 0:32:24.880
<v Speaker 1>Yes, can you have a quantum clock that maybe doesn't

0:32:24.960 --> 0:32:27.840
<v Speaker 1>use an atom, that maybe just relies on electrons or

0:32:28.000 --> 0:32:28.880
<v Speaker 1>quarks or something.

0:32:29.040 --> 0:32:31.920
<v Speaker 2>Yeah, sure, you're not limited to atoms. You can imagine

0:32:32.000 --> 0:32:35.320
<v Speaker 2>quantum clocks made out of like photons interacting or splitting

0:32:35.440 --> 0:32:38.800
<v Speaker 2>or bouncing or something like that. In some sense, lego

0:32:39.080 --> 0:32:42.400
<v Speaker 2>is a clock because it's measuring the time for photons

0:32:42.440 --> 0:32:45.760
<v Speaker 2>to travel along its legs, right, It's just converting that

0:32:45.800 --> 0:32:48.520
<v Speaker 2>to a distance measurement, and so you could have other

0:32:48.600 --> 0:32:51.040
<v Speaker 2>quantum clocks that are not based on atoms. Yes, And

0:32:51.120 --> 0:32:53.200
<v Speaker 2>one day, when we discover dark matter, maybe we could

0:32:53.200 --> 0:32:54.240
<v Speaker 2>build a clock.

0:32:53.960 --> 0:32:56.880
<v Speaker 1>Out of dark matter, which may or may not tell

0:32:56.920 --> 0:32:57.600
<v Speaker 1>you the time.

0:32:58.200 --> 0:32:59.960
<v Speaker 2>And may or may not smell like flatulin.

0:33:00.360 --> 0:33:02.040
<v Speaker 1>Well, I guess, maybe give us an example of like,

0:33:02.120 --> 0:33:05.880
<v Speaker 1>what's a typical or popular or a commonly used quantum

0:33:05.880 --> 0:33:06.960
<v Speaker 1>clock and how does it work.

0:33:07.240 --> 0:33:10.000
<v Speaker 2>Well, the most precise quantum clock is based on the

0:33:10.000 --> 0:33:13.120
<v Speaker 2>caesium one thirty three atom. That's the one that's actually

0:33:13.200 --> 0:33:16.440
<v Speaker 2>used to define what a second is. And so here

0:33:16.480 --> 0:33:19.480
<v Speaker 2>we have two states of electrons. There's a small splitting

0:33:19.520 --> 0:33:22.200
<v Speaker 2>in an energy state here. It's called a hyper fine

0:33:22.240 --> 0:33:24.920
<v Speaker 2>splitting because the difference is very very small, and when

0:33:24.920 --> 0:33:26.760
<v Speaker 2>the electron sits in there, it sort of goes back

0:33:26.800 --> 0:33:28.959
<v Speaker 2>and forth between the two different states.

0:33:29.200 --> 0:33:32.480
<v Speaker 1>Meaning like, this is an electron that's orbiting around the

0:33:32.520 --> 0:33:33.320
<v Speaker 1>caesium atom.

0:33:33.560 --> 0:33:35.600
<v Speaker 2>Yeah, I wouldn't say orbiting if we want to be

0:33:35.640 --> 0:33:38.440
<v Speaker 2>really really technical. But it's captured by the caesium atom.

0:33:38.640 --> 0:33:40.880
<v Speaker 1>And you're saying it's switching energy levels. Why would it

0:33:40.920 --> 0:33:41.960
<v Speaker 1>switch energy levels?

0:33:42.160 --> 0:33:44.360
<v Speaker 2>So you have this caesium atom and you embed the

0:33:44.360 --> 0:33:46.920
<v Speaker 2>whole thing in some microwave radiation that can lift those

0:33:46.920 --> 0:33:49.800
<v Speaker 2>electrons up from the lower state to the higher state.

0:33:50.000 --> 0:33:52.000
<v Speaker 1>Meaning you like put it in a microwave or you

0:33:52.040 --> 0:33:53.640
<v Speaker 1>shoot it with this like a light gun.

0:33:54.600 --> 0:33:56.880
<v Speaker 2>There's not a difference, right, that's what a microwave is.

0:33:56.920 --> 0:34:00.120
<v Speaker 2>A microwave is shooting microwave radiation at your food, and

0:34:00.160 --> 0:34:03.720
<v Speaker 2>microwaves are lights. Though basically a microwave is a light gun.

0:34:03.960 --> 0:34:06.320
<v Speaker 1>Sounds hot. So then you have this atom and you

0:34:06.320 --> 0:34:07.360
<v Speaker 1>you stick it in the microwave.

0:34:07.400 --> 0:34:09.719
<v Speaker 2>Uh huh, yeah, So you stick in the microwave and

0:34:09.760 --> 0:34:11.959
<v Speaker 2>you measure how often it jumps up and then down

0:34:12.000 --> 0:34:13.320
<v Speaker 2>and then up and then down.

0:34:13.320 --> 0:34:16.160
<v Speaker 1>Because the light, as the light passes through it, it

0:34:16.400 --> 0:34:18.400
<v Speaker 1>knocks the electron up and down or what.

0:34:18.640 --> 0:34:21.400
<v Speaker 2>Yeah, the light is tuned to exactly the frequency for

0:34:21.440 --> 0:34:24.720
<v Speaker 2>the electron to jump up into the higher energy level. Remember,

0:34:24.800 --> 0:34:27.000
<v Speaker 2>electrons can go from a lower to a higher energy

0:34:27.040 --> 0:34:29.600
<v Speaker 2>level if a photon of the right energy comes along.

0:34:29.960 --> 0:34:33.400
<v Speaker 2>So they've tuned this microwave to exactly that energy level.

0:34:33.600 --> 0:34:36.400
<v Speaker 2>So electrons and the lower level can absorb these photons

0:34:36.440 --> 0:34:38.720
<v Speaker 2>jump up to the higher level, but then they'll naturally

0:34:38.719 --> 0:34:42.160
<v Speaker 2>decay down because the universe likes to spread energy out,

0:34:42.400 --> 0:34:44.960
<v Speaker 2>and so the time of these oscillations turns out to

0:34:45.000 --> 0:34:48.080
<v Speaker 2>be very very regular, Like an electron will do this

0:34:48.280 --> 0:34:52.239
<v Speaker 2>nine point one nine to two billion times per second.

0:34:52.080 --> 0:34:54.399
<v Speaker 1>And it doesn't depend on the frequency of the light,

0:34:54.560 --> 0:34:54.959
<v Speaker 1>or it does.

0:34:55.080 --> 0:34:57.000
<v Speaker 2>It definitely depends on the frequency of the light. If

0:34:57.000 --> 0:34:59.279
<v Speaker 2>the frequency of the light is not correct, then it

0:34:59.280 --> 0:35:01.120
<v Speaker 2>won't even abso, right, it won't happen.

0:35:01.400 --> 0:35:04.160
<v Speaker 1>Oh but then don't you need to make that frequency

0:35:04.280 --> 0:35:05.040
<v Speaker 1>super precise?

0:35:05.200 --> 0:35:07.680
<v Speaker 2>Yeah, exactly, And this is one source of uncertainty in

0:35:07.719 --> 0:35:11.080
<v Speaker 2>these clocks, right, making those accurate. And you can measure

0:35:11.080 --> 0:35:13.279
<v Speaker 2>these things, like you build two independent ones, you can

0:35:13.320 --> 0:35:16.319
<v Speaker 2>see how their counts drift relative to each other. And

0:35:16.760 --> 0:35:19.080
<v Speaker 2>that's how you measure the accuracy of clocks. In general.

0:35:19.120 --> 0:35:21.359
<v Speaker 2>There's no absolute standard by which you can tell like, oh,

0:35:21.360 --> 0:35:23.200
<v Speaker 2>this clock is off or that clock is off. You

0:35:23.320 --> 0:35:24.799
<v Speaker 2>just build a few of them and you measure them

0:35:24.840 --> 0:35:27.239
<v Speaker 2>relative to each other. And this is something that we

0:35:27.360 --> 0:35:29.719
<v Speaker 2>know well enough. We know how to design the middle

0:35:29.719 --> 0:35:32.160
<v Speaker 2>of the physics and the engineering that you can build

0:35:32.200 --> 0:35:36.200
<v Speaker 2>these things so that atomic clocks in independent locations agree

0:35:36.600 --> 0:35:39.640
<v Speaker 2>to like zero point three nanoseconds per day. It's really

0:35:39.760 --> 0:35:40.920
<v Speaker 2>very incredibly precise.

0:35:41.400 --> 0:35:44.080
<v Speaker 1>WHOA, so what are you measuring? How are you measuring

0:35:44.120 --> 0:35:46.080
<v Speaker 1>whether these electrons are going up and down?

0:35:46.120 --> 0:35:48.960
<v Speaker 2>When the electron goes back down, it emits radiation, right,

0:35:49.000 --> 0:35:50.560
<v Speaker 2>and so you can gather that as.

0:35:50.400 --> 0:35:53.080
<v Speaker 1>Well, like it shoots off light, like it will blink.

0:35:52.840 --> 0:35:54.880
<v Speaker 2>Basically exactly little flash.

0:35:55.000 --> 0:35:57.120
<v Speaker 1>All right. So then, and you're saying you can build

0:35:57.200 --> 0:35:59.560
<v Speaker 1>these things now to be the size of a toaster

0:35:59.840 --> 0:36:02.240
<v Speaker 1>or or a microwave oven.

0:36:02.800 --> 0:36:05.840
<v Speaker 2>A quantum toaster. They have them now and they've deployed

0:36:05.840 --> 0:36:08.560
<v Speaker 2>them out in space. They actually built the Deep Space

0:36:08.600 --> 0:36:11.439
<v Speaker 2>Atomic Clock Mission and they sent an atomic clock out

0:36:11.480 --> 0:36:13.879
<v Speaker 2>into space to see, like, hey, can we operate one

0:36:13.880 --> 0:36:16.120
<v Speaker 2>of these things out in space? And you might wonder

0:36:16.200 --> 0:36:18.400
<v Speaker 2>like is this just a bunch of nerds trying to

0:36:18.400 --> 0:36:20.080
<v Speaker 2>do something that seems cool?

0:36:20.360 --> 0:36:22.759
<v Speaker 1>Yes? Is always the answer, Like can we shoot a

0:36:22.800 --> 0:36:26.480
<v Speaker 1>microwave into space and will it still heat up my burrito?

0:36:26.600 --> 0:36:29.000
<v Speaker 1>My seizing Burritoah? Is that the challenge?

0:36:29.040 --> 0:36:31.239
<v Speaker 2>That's the challenge. But also if we want to do

0:36:31.360 --> 0:36:35.160
<v Speaker 2>things like navigate in space, navigation needs timing. You need

0:36:35.200 --> 0:36:37.560
<v Speaker 2>to know like how long you're going in one direction.

0:36:37.760 --> 0:36:39.400
<v Speaker 2>If you want to do dead reckoning, you want to

0:36:39.400 --> 0:36:42.520
<v Speaker 2>know where you are. Timing is absolutely crucial. Or if

0:36:42.560 --> 0:36:46.240
<v Speaker 2>you want to use like nearby pulsars to triangulate your position,

0:36:46.520 --> 0:36:49.120
<v Speaker 2>my whole episode about how that works, you also need

0:36:49.280 --> 0:36:51.800
<v Speaker 2>very accurate timing so you can measure the time between

0:36:51.800 --> 0:36:54.680
<v Speaker 2>the pulses. So this was like a technological challenge that's

0:36:54.680 --> 0:36:57.879
<v Speaker 2>going to lay the groundwork for all sorts of cool innovations.

0:36:58.239 --> 0:37:01.440
<v Speaker 2>And this was totally successful, this deep space atomic clock mission.

0:37:01.640 --> 0:37:04.120
<v Speaker 1>Well, let's get into how you would actually use these

0:37:04.320 --> 0:37:07.840
<v Speaker 1>and how the timing might tell you where dark matter

0:37:07.960 --> 0:37:11.800
<v Speaker 1>is within our Solar system and maybe even within the Earth.

0:37:11.960 --> 0:37:14.360
<v Speaker 1>So let's dig into that. But first let's take another

0:37:14.440 --> 0:37:30.040
<v Speaker 1>quick break. All right, we're talking about using a microwave

0:37:30.160 --> 0:37:33.200
<v Speaker 1>stuck inside of a microwave to detect dark matter so

0:37:33.239 --> 0:37:36.440
<v Speaker 1>you can win a Tierra for being the prettiest scientist.

0:37:37.120 --> 0:37:39.560
<v Speaker 2>Yeah, exactly. Does it take longer to heat up your

0:37:39.560 --> 0:37:41.480
<v Speaker 2>burrito when there's dark matter around?

0:37:41.800 --> 0:37:44.200
<v Speaker 1>So the idea is that you take these atomic or

0:37:44.480 --> 0:37:47.120
<v Speaker 1>basically an atomic clock, which is a quantum clock, but

0:37:48.000 --> 0:37:50.840
<v Speaker 1>it seems like the most popular ones use atoms, and

0:37:50.920 --> 0:37:52.920
<v Speaker 1>so you shrink them down to the size of a

0:37:52.960 --> 0:37:54.920
<v Speaker 1>toaster or microwave and then you shoot them in space,

0:37:54.960 --> 0:37:57.080
<v Speaker 1>and then how does that help you measure dark matter?

0:37:57.840 --> 0:37:59.720
<v Speaker 2>Well, there were a bunch of physicists who thought, okay,

0:37:59.760 --> 0:38:02.000
<v Speaker 2>this is that's cool because now we not only have

0:38:02.280 --> 0:38:05.440
<v Speaker 2>all some super precise atomic clocks, but now we have

0:38:05.520 --> 0:38:08.000
<v Speaker 2>them spread out through the Solar System, like in principle

0:38:08.280 --> 0:38:10.160
<v Speaker 2>the way we like scent devices near the Sun with

0:38:10.200 --> 0:38:12.839
<v Speaker 2>a Parker solar probe. People are, what if we built

0:38:12.840 --> 0:38:14.719
<v Speaker 2>a bunch of these things and we spread them out

0:38:14.719 --> 0:38:17.040
<v Speaker 2>in the Solar system, could they give us a picture

0:38:17.080 --> 0:38:19.600
<v Speaker 2>of where the dark matter is in the Solar system

0:38:20.120 --> 0:38:23.400
<v Speaker 2>if they operate differently when there's dark matter around, like

0:38:23.440 --> 0:38:26.279
<v Speaker 2>if they're sensitive to the dark matter density, Like if

0:38:26.280 --> 0:38:29.680
<v Speaker 2>your atomic clock gets off if it drifts when there's

0:38:29.719 --> 0:38:32.360
<v Speaker 2>more or less dark matter around, than having a bunch

0:38:32.360 --> 0:38:35.120
<v Speaker 2>of these atomic clocks spread out through the Solar system

0:38:35.280 --> 0:38:37.440
<v Speaker 2>could give you a picture for where in the Solar

0:38:37.440 --> 0:38:38.759
<v Speaker 2>System the dark matter is.

0:38:39.400 --> 0:38:42.560
<v Speaker 1>But I guess what's the mechanism by which dark matter

0:38:42.600 --> 0:38:44.920
<v Speaker 1>would affect the timing of these clocks.

0:38:45.120 --> 0:38:47.960
<v Speaker 2>Yeah, so mostly it wouldn't. For many theories of dark matter,

0:38:48.080 --> 0:38:51.240
<v Speaker 2>dark matter is just some wimp. It's a massive particle

0:38:51.320 --> 0:38:54.480
<v Speaker 2>that only interacts gravitationally, and so it has essentially no

0:38:54.600 --> 0:38:58.360
<v Speaker 2>effect on these clocks except for gravitational time dilation. We

0:38:58.400 --> 0:39:01.279
<v Speaker 2>know the areas with greater mass more curvature, and a

0:39:01.360 --> 0:39:04.000
<v Speaker 2>curvature causes time dilation, but that would be very, very

0:39:04.040 --> 0:39:06.560
<v Speaker 2>difficult to measure even with these quantum clocks.

0:39:06.640 --> 0:39:08.200
<v Speaker 1>But wait, wait, why would it be difficult.

0:39:08.239 --> 0:39:11.239
<v Speaker 2>You can measure gravitational time dilation with quantum clocks, and

0:39:11.280 --> 0:39:13.400
<v Speaker 2>we've done that. You can do it on the surface

0:39:13.440 --> 0:39:15.360
<v Speaker 2>of the Earth, for example, and you could put a

0:39:15.400 --> 0:39:18.440
<v Speaker 2>quantum clock one meter above another one and you can

0:39:18.480 --> 0:39:21.080
<v Speaker 2>see the difference between them because one of them is

0:39:21.120 --> 0:39:24.240
<v Speaker 2>deeper in the curvature than the other. Super duper awesome,

0:39:24.480 --> 0:39:26.480
<v Speaker 2>but that's because the Earth has a huge amount of

0:39:26.520 --> 0:39:30.240
<v Speaker 2>gravity and this significant curvature. Here. Dark matter doesn't contribute

0:39:30.280 --> 0:39:34.000
<v Speaker 2>significantly to the curvature because it's pretty spread out, and

0:39:34.120 --> 0:39:36.960
<v Speaker 2>we would already know if dark matter wasn't pretty spread out,

0:39:37.120 --> 0:39:39.640
<v Speaker 2>because we would have seen deviations and like Jupiter's orbit

0:39:39.680 --> 0:39:42.399
<v Speaker 2>and whatever. So in principle you can, but we don't

0:39:42.400 --> 0:39:44.120
<v Speaker 2>think it's going to be very sensitive. If you had

0:39:44.120 --> 0:39:46.560
<v Speaker 2>a lot of quantum clocks and there were much more sensitive,

0:39:46.719 --> 0:39:50.239
<v Speaker 2>then you could probably detect dark matter local density variations

0:39:50.520 --> 0:39:51.000
<v Speaker 2>using that.

0:39:51.000 --> 0:39:54.640
<v Speaker 1>Principle, meaning these clocks would take at a different frequency

0:39:55.400 --> 0:39:58.799
<v Speaker 1>depending on how close it was to big sources of

0:39:58.880 --> 0:40:02.040
<v Speaker 1>mass or even sources of mass, because that's just how

0:40:02.120 --> 0:40:02.960
<v Speaker 1>relativity works.

0:40:03.080 --> 0:40:05.279
<v Speaker 2>Yeah, that's how relativity works. Remember, in relativity, it is

0:40:05.320 --> 0:40:08.200
<v Speaker 2>two kinds of time dilation. One is based on speed.

0:40:08.239 --> 0:40:10.680
<v Speaker 2>If you see a clock moving quickly, then you see

0:40:10.680 --> 0:40:14.120
<v Speaker 2>it ticking slowly, and that's very confusing because it's relative,

0:40:14.160 --> 0:40:16.560
<v Speaker 2>and so it depends on two observers. But there's another

0:40:16.680 --> 0:40:20.160
<v Speaker 2>kind of time dilation, gravitational, which is absolute. It just

0:40:20.160 --> 0:40:23.680
<v Speaker 2>says anybody in curvature their clock is going to tick slowly,

0:40:23.840 --> 0:40:25.759
<v Speaker 2>no matter who's looking at it, and everybody's going to

0:40:25.800 --> 0:40:29.280
<v Speaker 2>agree about whose clock is ticking slowly. So that's very powerful,

0:40:29.560 --> 0:40:32.080
<v Speaker 2>and that's something you can use to measure just like

0:40:32.160 --> 0:40:35.239
<v Speaker 2>how much stuff is there in general, because clocks tick

0:40:35.360 --> 0:40:38.360
<v Speaker 2>slower near stuff. Really kind of an awesome feature of

0:40:38.440 --> 0:40:39.560
<v Speaker 2>the universe.

0:40:39.239 --> 0:40:41.280
<v Speaker 1>Meaning like if I had two of these atomic clocks

0:40:41.280 --> 0:40:42.800
<v Speaker 1>and one of them is out there in the middle

0:40:42.840 --> 0:40:45.120
<v Speaker 1>of empty space, and the other one is near a

0:40:45.120 --> 0:40:47.319
<v Speaker 1>big blob of dark matter. The one near the blob

0:40:47.360 --> 0:40:50.480
<v Speaker 1>of dark matter would take slower.

0:40:50.160 --> 0:40:51.960
<v Speaker 2>Right, Yeah, that's exactly right.

0:40:52.000 --> 0:40:54.120
<v Speaker 1>And so you might like start them out in the

0:40:54.160 --> 0:40:57.840
<v Speaker 1>same spot. But then after being for a while and

0:40:57.880 --> 0:40:59.600
<v Speaker 1>two different spots, one near the dark matter, and you

0:40:59.719 --> 0:41:01.640
<v Speaker 1>run a back, you would see that one of them

0:41:02.000 --> 0:41:03.400
<v Speaker 1>take more ticks than the other.

0:41:03.640 --> 0:41:03.799
<v Speaker 3>Yeah.

0:41:03.920 --> 0:41:06.640
<v Speaker 2>So now imagine like a grid, you have a quantum

0:41:06.719 --> 0:41:09.799
<v Speaker 2>clock every ten meters in the solar system, right, you

0:41:09.800 --> 0:41:11.480
<v Speaker 2>start them all out at the same time, and then

0:41:11.520 --> 0:41:13.759
<v Speaker 2>you monitor it, and by measuring the difference in that

0:41:13.920 --> 0:41:16.560
<v Speaker 2>number of ticks after a year on your reference clock,

0:41:16.600 --> 0:41:19.120
<v Speaker 2>the one that's hanging out with you, you can tell where

0:41:19.160 --> 0:41:21.200
<v Speaker 2>stuff is in the solar system.

0:41:21.040 --> 0:41:24.759
<v Speaker 1>Like which spots in the solar system have slower time.

0:41:24.680 --> 0:41:28.520
<v Speaker 2>Yes, exactly, because slower time means more matter, more curvature,

0:41:28.600 --> 0:41:29.600
<v Speaker 2>more energy density.

0:41:29.640 --> 0:41:31.960
<v Speaker 1>Really, I guess, on top of what you already know

0:41:32.080 --> 0:41:35.239
<v Speaker 1>about the Solar system right like right now, even if

0:41:35.239 --> 0:41:38.399
<v Speaker 1>we didn't have dark matter, a clock near the Sun

0:41:38.400 --> 0:41:40.520
<v Speaker 1>would take slower than a clock here exactly.

0:41:40.680 --> 0:41:43.040
<v Speaker 2>And we've done some basic version of this, as I

0:41:43.040 --> 0:41:46.319
<v Speaker 2>said earlier, If a few clocks on Earth at different altitudes,

0:41:46.719 --> 0:41:48.920
<v Speaker 2>those are different distances from the matter of the Earth

0:41:48.960 --> 0:41:52.239
<v Speaker 2>and the ones closer do ticks more slowly, and satellites

0:41:52.320 --> 0:41:55.800
<v Speaker 2>up in space their clocks tick faster than atomic clocks

0:41:55.800 --> 0:41:57.120
<v Speaker 2>here on the surface of the Earth. And you've got

0:41:57.120 --> 0:42:00.000
<v Speaker 2>to take that new account famously when you're doing GPS,

0:42:00.000 --> 0:42:00.439
<v Speaker 2>et cetera.

0:42:00.600 --> 0:42:03.760
<v Speaker 1>But you're saying, we're not going to be using this effect,

0:42:03.960 --> 0:42:07.200
<v Speaker 1>this time dilation from relativity to measure dark matter. Dark

0:42:07.200 --> 0:42:08.319
<v Speaker 1>matter is just too weak.

0:42:08.480 --> 0:42:10.160
<v Speaker 2>Dark matter is too weak, and we think it's not

0:42:10.239 --> 0:42:12.360
<v Speaker 2>cluppy enough to really detect that, though it would be

0:42:12.400 --> 0:42:15.680
<v Speaker 2>super awesome. There's a special kind of dark matter which

0:42:15.880 --> 0:42:18.880
<v Speaker 2>might give much larger effects, which would be much easier

0:42:18.920 --> 0:42:22.280
<v Speaker 2>to discover. And this is a theory called fuzzy dark matter.

0:42:22.680 --> 0:42:27.439
<v Speaker 1>Sounds fuzzy. But wait, so you're saying, like this idea

0:42:27.480 --> 0:42:30.520
<v Speaker 1>of using atomic clocks to measure dark matter would only

0:42:30.560 --> 0:42:37.160
<v Speaker 1>work for a certain theoretical meaning guessie type of dark matter,

0:42:37.320 --> 0:42:39.279
<v Speaker 1>which we don't know whether it's true or not or

0:42:39.280 --> 0:42:42.320
<v Speaker 1>exists or not. M So this is a huge sources

0:42:42.360 --> 0:42:45.839
<v Speaker 1>in white scheme that you don't really know if it's

0:42:45.840 --> 0:42:46.279
<v Speaker 1>going to work.

0:42:46.360 --> 0:42:48.279
<v Speaker 2>You know, you were talking about nomenclature and now you're

0:42:48.320 --> 0:42:51.080
<v Speaker 2>using the words guess and scheme. You know, really kind

0:42:51.080 --> 0:42:53.279
<v Speaker 2>of undermine the credibility of science, but you know, this

0:42:53.480 --> 0:42:55.719
<v Speaker 2>is good faith stuff. This is like, hey, what if

0:42:55.800 --> 0:42:58.640
<v Speaker 2>dark matter is this other weird particular thing. How could

0:42:58.719 --> 0:43:01.320
<v Speaker 2>we see that and yet be best if we had experiments

0:43:01.320 --> 0:43:03.880
<v Speaker 2>which could detect any kind of dark matter. But you know,

0:43:03.920 --> 0:43:05.719
<v Speaker 2>there might be kinds of dark matter which we could

0:43:05.760 --> 0:43:08.360
<v Speaker 2>only detect in certain ways or easier to spot in

0:43:08.400 --> 0:43:10.279
<v Speaker 2>some ways. And so it's good to be creative and

0:43:10.320 --> 0:43:13.399
<v Speaker 2>think about how we could detect specific kinds of dark

0:43:13.440 --> 0:43:15.719
<v Speaker 2>matter as well, even though we don't know what dark

0:43:15.719 --> 0:43:17.600
<v Speaker 2>matter is. And if this theory is at.

0:43:17.440 --> 0:43:20.280
<v Speaker 1>All correct, well, I'm just trying to understand the scheme.

0:43:22.440 --> 0:43:24.680
<v Speaker 1>So are you saying there's a theoretical kind of dark

0:43:24.680 --> 0:43:26.880
<v Speaker 1>matter called fuzzy dark matter? So what is it? So?

0:43:27.040 --> 0:43:30.800
<v Speaker 2>Fuzzy dark matter suggests that maybe dark matter isn't very massive,

0:43:31.200 --> 0:43:33.640
<v Speaker 2>like some people suggest that dark matter could be like

0:43:33.719 --> 0:43:36.360
<v Speaker 2>one hundred GeV like the mass of a w or

0:43:36.360 --> 0:43:39.000
<v Speaker 2>a z boson, like one hundred times the mass of

0:43:39.040 --> 0:43:42.440
<v Speaker 2>a proton, a pretty hefty particle, almost as massive as

0:43:42.440 --> 0:43:45.439
<v Speaker 2>a Higgs. That's sort of the classic strategy, and there's

0:43:45.480 --> 0:43:48.359
<v Speaker 2>reasons for that. There's something called the wimp miracle check

0:43:48.400 --> 0:43:51.640
<v Speaker 2>in our podcast about that, which argues strongly that dark

0:43:51.680 --> 0:43:54.200
<v Speaker 2>matter should be around one hundred gv based on how

0:43:54.320 --> 0:43:56.560
<v Speaker 2>much of it there is in the universe. But people

0:43:56.600 --> 0:43:58.120
<v Speaker 2>are like, well, maybe that's all wrong, and there's an

0:43:58.120 --> 0:44:01.399
<v Speaker 2>assumption there that's wrong. What if dark matter super duper light,

0:44:01.680 --> 0:44:04.680
<v Speaker 2>like a trilliance the mass of an electron. So now

0:44:04.719 --> 0:44:07.840
<v Speaker 2>there's an enormous number of these dark matter particles, so

0:44:08.080 --> 0:44:10.520
<v Speaker 2>many more than you could even imagine, because you have

0:44:10.560 --> 0:44:13.480
<v Speaker 2>to somehow make like a big fraction of the mass

0:44:13.480 --> 0:44:16.320
<v Speaker 2>of the universe out of particles that are a tiny

0:44:16.360 --> 0:44:19.200
<v Speaker 2>fraction of the mass of the electron, which is already

0:44:19.320 --> 0:44:20.080
<v Speaker 2>very very light.

0:44:20.280 --> 0:44:22.440
<v Speaker 1>Well, first of all, I think this whole podcast is

0:44:22.440 --> 0:44:26.360
<v Speaker 1>a wimp miracle, Daniel. But I think you're saying, like

0:44:26.600 --> 0:44:29.760
<v Speaker 1>this version of dark matter, instead of being maybe marble

0:44:29.840 --> 0:44:33.560
<v Speaker 1>sized particles, they're like super tiny bb sized particles. And

0:44:33.600 --> 0:44:34.880
<v Speaker 1>some of that makes it fuzzier.

0:44:35.000 --> 0:44:37.200
<v Speaker 2>Yeah, it makes it fuzzier because if they're very very

0:44:37.239 --> 0:44:40.839
<v Speaker 2>low mass, then their wavelengths are more spread out. Some

0:44:40.920 --> 0:44:43.120
<v Speaker 2>of these things can have a wavelength like the size

0:44:43.120 --> 0:44:43.880
<v Speaker 2>of the galaxy.

0:44:44.120 --> 0:44:45.120
<v Speaker 1>What do you mean a wavelength?

0:44:45.320 --> 0:44:47.759
<v Speaker 2>The wavelength of a particle is like the distance on

0:44:47.800 --> 0:44:51.640
<v Speaker 2>which these quantum interference effects appear, and so you can

0:44:51.680 --> 0:44:54.879
<v Speaker 2>calculate this quantity. It's called the Debrogely wavelength. You'll see

0:44:54.960 --> 0:44:58.520
<v Speaker 2>wave like effects for a particle when you interact over

0:44:58.560 --> 0:45:01.760
<v Speaker 2>these kinds of distances, and that's the wavelength of a particle.

0:45:01.480 --> 0:45:03.680
<v Speaker 1>Meaning sort of like the size of it kind of right.

0:45:03.640 --> 0:45:05.799
<v Speaker 2>Sort of, Yeah, it's when it stops acting like a

0:45:05.840 --> 0:45:08.920
<v Speaker 2>blob like a particle and starts acting more like a wave.

0:45:09.080 --> 0:45:12.600
<v Speaker 2>Things that have wavelike behaviors. Really, it's always acting like

0:45:12.640 --> 0:45:14.200
<v Speaker 2>a wave. It's just that when you zoom out you

0:45:14.200 --> 0:45:15.840
<v Speaker 2>can approximate it as a particle.

0:45:15.960 --> 0:45:18.719
<v Speaker 1>Because they have low mass. What's the relationship between having

0:45:18.760 --> 0:45:21.320
<v Speaker 1>low mass and being having big wavelengths.

0:45:21.600 --> 0:45:24.200
<v Speaker 2>Well, the wavelength depends on your momentum and your mass,

0:45:24.400 --> 0:45:28.120
<v Speaker 2>So lower mass just means a larger wavelength because it's

0:45:28.160 --> 0:45:31.000
<v Speaker 2>really like a ratio between the momentum and the mass.

0:45:31.040 --> 0:45:33.160
<v Speaker 2>When things have a lot of kinetic energy relative to

0:45:33.160 --> 0:45:35.840
<v Speaker 2>their mass, they act more like light because light is

0:45:35.960 --> 0:45:38.640
<v Speaker 2>pure kinetic energy. When things have very small amounts of

0:45:38.680 --> 0:45:41.520
<v Speaker 2>energy relative to their mass, they're stationary, so they act

0:45:41.560 --> 0:45:44.680
<v Speaker 2>more like bits of sand, like particles, and so it's

0:45:44.680 --> 0:45:47.120
<v Speaker 2>just sort of a rough way to understand where that

0:45:47.120 --> 0:45:48.120
<v Speaker 2>transition happens.

0:45:48.440 --> 0:45:50.360
<v Speaker 1>Okay, So, then if dark matter is this kind of

0:45:50.440 --> 0:45:53.280
<v Speaker 1>fuzzy kind of dark matter, you're saying that each particle

0:45:53.280 --> 0:45:56.239
<v Speaker 1>would be super duper light, and it would also have

0:45:56.440 --> 0:45:59.920
<v Speaker 1>huge variations in their size. That's what you mean by fuzzy.

0:46:00.000 --> 0:46:01.960
<v Speaker 1>It's like they might be some of them might be

0:46:01.960 --> 0:46:03.640
<v Speaker 1>super big and somewhere might be super small.

0:46:03.880 --> 0:46:06.399
<v Speaker 2>Yeah. Well, the wavelengths could be very very large, which

0:46:06.400 --> 0:46:09.040
<v Speaker 2>means they can interact over long distances. But the fascinating

0:46:09.080 --> 0:46:11.600
<v Speaker 2>thing is that in simulations of this dark matter, it

0:46:11.680 --> 0:46:14.520
<v Speaker 2>predicts like a mini halo of dark matter in our

0:46:14.600 --> 0:46:17.560
<v Speaker 2>Solar system, essentially that this stuff would be clumped up

0:46:17.600 --> 0:46:20.560
<v Speaker 2>in and near the Sun. That most of the dark

0:46:20.600 --> 0:46:23.520
<v Speaker 2>matter in the Solar System might be like clumped up

0:46:23.600 --> 0:46:26.120
<v Speaker 2>near the Sun. It might be like hiding in the Sun.

0:46:26.719 --> 0:46:28.719
<v Speaker 1>And if it wasn't this kind of fuzzy dark matter,

0:46:28.800 --> 0:46:29.320
<v Speaker 1>it wouldn't.

0:46:29.560 --> 0:46:31.880
<v Speaker 2>Now, this kind of fuzzy dark matter is the kind

0:46:31.920 --> 0:46:33.440
<v Speaker 2>we think would clump up like a.

0:46:33.400 --> 0:46:35.840
<v Speaker 1>Halo near the Sun, and the other kinds wouldn't.

0:46:35.920 --> 0:46:38.359
<v Speaker 2>Yeah, the other kinds wouldn't necessarily, I mean, I've heard

0:46:38.400 --> 0:46:40.960
<v Speaker 2>of other theories of dark matter clumping in the Sun.

0:46:40.960 --> 0:46:44.200
<v Speaker 2>There's all sorts of theories, but this particular one tends

0:46:44.239 --> 0:46:47.120
<v Speaker 2>to make a halo near the Sun and would affect

0:46:47.120 --> 0:46:50.440
<v Speaker 2>the operation of quantum clocks because of its special fuzziness.

0:46:50.600 --> 0:46:53.960
<v Speaker 2>It can also slightly interact with electrons through sort of

0:46:54.000 --> 0:46:56.560
<v Speaker 2>like a back door in quantum mechanics, which would change

0:46:56.600 --> 0:46:59.120
<v Speaker 2>the way a quantum clock operates. It's like it changes

0:46:59.160 --> 0:47:02.680
<v Speaker 2>the electrons math and how it responds to photons because

0:47:02.719 --> 0:47:06.480
<v Speaker 2>of oscillations in this fuzzy dark matter field, and so

0:47:06.640 --> 0:47:10.239
<v Speaker 2>effectively it changes the frequency of these clocks. And so

0:47:10.320 --> 0:47:13.360
<v Speaker 2>you can detect in principle whether you're near a dense

0:47:13.440 --> 0:47:16.640
<v Speaker 2>blob of this ultra light dark matter by looking at

0:47:16.640 --> 0:47:19.560
<v Speaker 2>a quantum clock and counting its ticks very carefully. And

0:47:19.600 --> 0:47:21.520
<v Speaker 2>this would be a bigger effect than the effect we

0:47:21.800 --> 0:47:24.000
<v Speaker 2>talked about earlier, the gravitational curvature.

0:47:24.120 --> 0:47:26.680
<v Speaker 1>But I thought that dark matter couldn't interact with regular

0:47:26.719 --> 0:47:29.280
<v Speaker 1>matter only through it could only do it through gravity.

0:47:29.400 --> 0:47:31.800
<v Speaker 2>Yeah, it could only do it through gravity in general,

0:47:31.840 --> 0:47:34.080
<v Speaker 2>But this one takes a back door through the Higgs field.

0:47:34.400 --> 0:47:36.640
<v Speaker 2>It like interacts with the Higgs field and it changes

0:47:36.640 --> 0:47:39.280
<v Speaker 2>how the Higgs field works, and so near the presence

0:47:39.280 --> 0:47:41.960
<v Speaker 2>of this ultra light dark matter, electrons effectively have a

0:47:42.000 --> 0:47:42.840
<v Speaker 2>different mass.

0:47:43.800 --> 0:47:46.080
<v Speaker 1>But I guess if that was true, wouldn't we see

0:47:46.280 --> 0:47:49.200
<v Speaker 1>it effect regular matter on a larger scale.

0:47:49.280 --> 0:47:51.200
<v Speaker 2>You would see it happen, but it's a subtle effect,

0:47:51.360 --> 0:47:53.400
<v Speaker 2>and so you need to be near a dense clump

0:47:53.480 --> 0:47:56.319
<v Speaker 2>of it. So the idea is, take something that's very

0:47:56.360 --> 0:47:58.920
<v Speaker 2>very sensitive to the electron mass, like a quantum clock,

0:47:59.120 --> 0:48:01.160
<v Speaker 2>and try to put it near a dense clump of

0:48:01.160 --> 0:48:04.160
<v Speaker 2>this special ultra light dark matter, maybe near the Sun.

0:48:04.800 --> 0:48:06.640
<v Speaker 2>So that's the idea is, like launch a bunch of

0:48:06.719 --> 0:48:09.279
<v Speaker 2>quantum clocks, have them orbit near the Sun, and look

0:48:09.320 --> 0:48:12.560
<v Speaker 2>for deviations in their timekeeping, and see if that's evidence

0:48:12.680 --> 0:48:15.920
<v Speaker 2>for ultra light dark matter interfering with the masses of

0:48:15.960 --> 0:48:17.880
<v Speaker 2>the electrons in these quantum clocks.

0:48:18.040 --> 0:48:19.959
<v Speaker 1>We mean that you would maybe like throw a bunch

0:48:19.960 --> 0:48:22.719
<v Speaker 1>of the sun, have them kind of form a half

0:48:22.840 --> 0:48:25.719
<v Speaker 1>ring around the Sun to see if time changes there,

0:48:25.880 --> 0:48:28.399
<v Speaker 1>sort of like a giant tirra, like.

0:48:28.440 --> 0:48:31.280
<v Speaker 2>A giant tr a quantum cosmic tira.

0:48:31.560 --> 0:48:33.600
<v Speaker 1>All right, But I guess which one would you be proving?

0:48:33.640 --> 0:48:36.640
<v Speaker 1>Would you be proving that dark matter is fuzzy, or

0:48:36.719 --> 0:48:39.680
<v Speaker 1>would you be proving that it's there? Or are they

0:48:39.719 --> 0:48:40.320
<v Speaker 1>both related?

0:48:40.520 --> 0:48:41.360
<v Speaker 2>They're both related.

0:48:41.400 --> 0:48:41.600
<v Speaker 4>Though.

0:48:41.680 --> 0:48:43.920
<v Speaker 2>You know, if we saw this thing, there would instantly

0:48:43.960 --> 0:48:46.719
<v Speaker 2>be like fifty other theories to explain it as well.

0:48:47.000 --> 0:48:49.719
<v Speaker 2>It probably wouldn't be a unique prediction of this kind

0:48:49.760 --> 0:48:52.320
<v Speaker 2>of dark matter. Theories are very very clever people, and

0:48:52.360 --> 0:48:54.640
<v Speaker 2>they'll always come up with another way to explain the

0:48:54.719 --> 0:48:57.440
<v Speaker 2>data that we were seeing. But it's cool because it's

0:48:57.440 --> 0:48:59.719
<v Speaker 2>a prediction that this theory makes and we go out

0:48:59.760 --> 0:49:02.160
<v Speaker 2>and we see it. That's really fascinating, and then we

0:49:02.200 --> 0:49:04.760
<v Speaker 2>can think about ways to distinguish all the different ideas

0:49:04.760 --> 0:49:08.120
<v Speaker 2>that might also explain this kind of observation. It would

0:49:08.200 --> 0:49:10.640
<v Speaker 2>just be cool to see something different. Currently, all of

0:49:10.640 --> 0:49:14.279
<v Speaker 2>our dark matter experiments basically see nothing. It would be

0:49:14.320 --> 0:49:15.760
<v Speaker 2>cool to have a signal somewhere.

0:49:16.680 --> 0:49:18.880
<v Speaker 1>So you're thinking, hey, let's put a bunch of microways

0:49:18.880 --> 0:49:21.280
<v Speaker 1>in space and see if it sticks exactly.

0:49:21.360 --> 0:49:23.240
<v Speaker 2>Let's see if one burrito is a little bit colder

0:49:23.280 --> 0:49:23.760
<v Speaker 2>than another.

0:49:24.040 --> 0:49:26.680
<v Speaker 1>All right, Well, an interesting idea for how we could

0:49:26.760 --> 0:49:31.600
<v Speaker 1>maybe possibly crack sort of a theoretical version of one

0:49:31.600 --> 0:49:33.360
<v Speaker 1>of the biggest mysteries in the universe.

0:49:33.560 --> 0:49:35.840
<v Speaker 2>That's right. Physicists are being very creative and trying to

0:49:35.840 --> 0:49:38.200
<v Speaker 2>come up with new theories of dark matter and new

0:49:38.239 --> 0:49:42.000
<v Speaker 2>ways to discover them, including using super duper sets in

0:49:42.160 --> 0:49:46.040
<v Speaker 2>quantum clocks distributed through the solar system, which also would

0:49:46.080 --> 0:49:46.839
<v Speaker 2>just be fun to do.

0:49:47.120 --> 0:49:49.920
<v Speaker 1>You just want to parade, Daniel, I just want a Tiara?

0:49:50.120 --> 0:49:51.560
<v Speaker 2>Is that too much to ask?

0:49:53.600 --> 0:49:55.120
<v Speaker 1>How about we just buy you a Tiara?

0:49:55.600 --> 0:49:57.440
<v Speaker 2>Is it made of dark matter? Are you using your bitcoin?

0:49:57.600 --> 0:49:59.440
<v Speaker 1>It can be, but in any way that you want.

0:50:00.480 --> 0:50:03.759
<v Speaker 1>But if it's saves tax dollars billions of dollars, you know,

0:50:03.800 --> 0:50:05.000
<v Speaker 1>it would be a pretty good investment.

0:50:05.040 --> 0:50:07.239
<v Speaker 2>Yeah, there we go. That was my scheme the whole time.

0:50:07.400 --> 0:50:10.640
<v Speaker 1>Yeah, to get us to buy you at tiara without

0:50:10.680 --> 0:50:12.480
<v Speaker 1>actually having to run in a beauty contest.

0:50:13.920 --> 0:50:14.560
<v Speaker 2>I'm busted.

0:50:15.600 --> 0:50:19.520
<v Speaker 1>Well, you are the most beautiful podcaster with a show

0:50:19.560 --> 0:50:23.040
<v Speaker 1>called Daniel Jorge Explaining the Universe. So whose name is Daniels?

0:50:23.160 --> 0:50:25.319
<v Speaker 2>I'll take very highly qualified compliments, thank you.

0:50:26.680 --> 0:50:30.719
<v Speaker 1>It's a very specific tiara based on a very theoretical

0:50:31.440 --> 0:50:33.080
<v Speaker 1>model of the universe.

0:50:33.080 --> 0:50:34.839
<v Speaker 2>Fuzzy compliments from Morehey, all.

0:50:34.800 --> 0:50:37.319
<v Speaker 1>Right, well we hope you enjoyed that. Thanks for joining us.

0:50:37.880 --> 0:50:38.680
<v Speaker 1>See you next time.

0:50:43.480 --> 0:50:46.680
<v Speaker 2>For more science and curiosity, come find us on social media,

0:50:46.760 --> 0:50:51.360
<v Speaker 2>where we answer questions and post videos. We're on Twitter, Discord, Instant,

0:50:51.440 --> 0:50:55.240
<v Speaker 2>and now TikTok. Thanks for listening, and remember that Daniel

0:50:55.239 --> 0:50:58.600
<v Speaker 2>and Jorge Explain the Universe is a production of Iheartworting.

0:50:59.000 --> 0:51:04.160
<v Speaker 2>For more podcast from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,

0:51:04.239 --> 0:51:06.600
<v Speaker 2>or wherever you listen to your favorite shows.