The Kavli Prize in Astrophysics: meet the 2024 laureates David Charbonneau and Sara Seager

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Hello, and welcome to the Physics World weekly

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podcast.

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I'm Hamish Johnston.

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This episode is sponsored by the cavalry prize.

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The cavalry prize honors scientists for breakthroughs

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in astro,

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nano neuroscience, and neuroscience.

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Transforming our understanding of the big, the small

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and the complex.

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The vision for the cavalry prize comes from

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Fred C, a Norwegian American entrepreneur

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and philanthropist

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who turned his lifelong

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fascination with science.

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Into a lasting legacy for recognizing

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scientific breakthroughs

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and for supporting basic

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research.

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The 20 24

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cavalry prize in astro

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was announced yesterday

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on the twelfth of June.

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I'm very pleased to have this year's Lau

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join me down the line from Cambridge

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Massachusetts.

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They are David Char

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of Harvard University

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and Sara Sig of the Massachusetts

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institute of technology.

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They share this year's cavalry prize in astro

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for their groundbreaking

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work on the discovery and

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characterization of extra solar planets and their atmospheres.

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Hi, Sarah, and David,

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welcome to the podcast.

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And

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congratulations for winning the Cavalry prize in astro.

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Thank you. It's great to be here. It's

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great to be here with you. So, Sarah,

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my my first question is for you.

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Astronomers have confirmed the existence of more than

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5000

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exoplanets.

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And that number keeps rising.

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And they have wonderful

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descriptions such as hot jupiter,

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mini neptune,

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and super earth.

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Can you give us a flavor of the

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different types of exoplanets that astronomers know of?

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Well, what's really truly amazing is there's a

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continuum of planets in terms of their mass,

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sizes and orbits, and it's very astonishing and

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what's completely unexpected.

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But these hot jupiter, they're just jupiter,

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mass, jupiter sized planets

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that are extremely close to there's host stars.

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So their atmospheres are heated to 3000

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even 3000 kelvin.

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The mini neptune are particularly exciting because

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Right now, we think we're on the verge

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of figuring out what they actually are. Their

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planets in between the size of earth's and

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Neptune.

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Earth, neptune is 4 times the size of

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earth.

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And so far, these

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mini neptune appear to be incredibly common in

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our galaxy. Yet, we have no solar system

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counterpart,

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and they have a very awkward ambiguous average

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density, so we don't know, for example, if

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they're rocky world surrounded by a subs,

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hydrogen or hydrogen helium envelope, or if they're

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this mysterious water world, a type of scaled

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up version of 1 of Jupiter's Icy moons

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that's

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largely water by mass.

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But there's so many. We could literally just

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have a monologue hours long of all the

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different planet types out there, they seem strange

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to us, but it it is that simply

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because we we only know about the solar

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system, and you know, the the the idea

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of a of a a hot Jupiter was

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almost beyond our imagination before we started detecting

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them.

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That's right. It's never good in science when

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we only have 1 example to build an

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entire theory on planet information based on the

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solar system.

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So the large majority of... Astronomers of scientists

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were completely shocked about the hot jupiter and

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everything else. But by now, honestly, we've learned

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to be surprised.

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1 thing we're dying to know, at least

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I'm dying to know is how common is

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our solar system.

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Our solar system is actually very hard to

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find. That works in our favor, we might

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not be here talking

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because we've had such a rich diversity of

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planets to discover.

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But in the near future, we hope to

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get an answer for that with 1 of

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our next telescopes the Nancy Grace Roman telescope

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that's going to do a micro lens survey

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and can take the sense. But right now,

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it could be that, you know, 10 percent

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or less of sunlight like Sars have an

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actual solar system.

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Do you have a you're you're a pioneer

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in the the study of the atmospheres of

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Exoplanets.

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How do astronomers

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study the atmospheres of these planets that are

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so far away and and so faint

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compared to the stars that they orbit,

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There are 2

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related methods

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that astronomers use and that Sarah and I

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have used to explore the atmospheres of these

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exoplanets.

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And they both have to do with

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a very special geometry. When our line of

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sight is aligned with the orbit of the

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planet around the star, and that means that

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once every orbit the planet passes

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in front of the star.

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And when it does so, some of the

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light from the star,

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passes through

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the atmosphere of the planet. And so if

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you were if you were looking at the

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start at that exact moment, you could imagine

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seeing this little planet in front of it

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and then seeing an ann, which is the

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atmosphere surrounding that planet.

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And so what we're doing is we're using

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the light from the star

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as a probe as a as a back

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light

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to probe the atmospheric chemistry,

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and that means that we don't have to

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spatial resolve

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the planet from the star. We don't have

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to be able to take a picture of

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the planet isolated from its star,

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which is very demanding in terms of optical

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design. We can instead use this,

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this trick and many, many people now use

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this trick all the time.

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The

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the other method is when the planet passes

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behind the star,

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then the planet is entirely out of you,

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and you might think well, that's no good

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because we're not seeing any life from the

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planet. But what that allows us to do

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is to measure the

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radiation, the thermal radiation from the star by

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itself.

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And we can then subtract that from data

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gathered at any other time when we have

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both the thermal radiation from the planet in

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the star and whatever's is left over, okay,

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However, small that residual signal might be. That

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is the radiation from the planet.

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And that's complimentary because that tells us the

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actual thermal emission,

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whereas the first method tells us about the

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opacity.

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And so we can learn a a great

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deal from these 2 methods.

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And David, when when you study the the

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light that that travels through the atmosphere, are

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you looking at bit? At light at certain

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frequencies that's been removed

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from the solar spectrum,

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or can can can you actually see light

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that's given off by,

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molecules and atoms in the atmosphere?

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That's right. The the ideas we're seeing the

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absorption

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due to whatever

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atoms or molecules are present in the atmosphere.

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And so as the light from the star

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passes through, certain specific wavelengths blanks are removed,

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and that's because they're being absorbed.

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And course, that only happens at the exact

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moment when the planet goes in front of

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the star. So we we can

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be be confident that that absorption really is

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due to the planetary atmosphere. Of

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But but we can't see emission at the

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moment or maybe we'll never see

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emission from the atmosphere because the star is

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is just so bright.

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We didn't don't see emission during transmission spectroscopy

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because the light from the star goes through

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the atmosphere and gets absorbed.

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And yes, the light is re emitted, but

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in all directions. So there's just such a

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tiny amount we never see it. Yeah. So,

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no. We do very much wanna study the

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emission from the planetary atmosphere.

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But the the best time to do that

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is not when the planets in front of

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the star, but rather when it is at

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some other point in its orbit.

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So so you can imagine if you were

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looking at the system and seeing it at

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quad we're seeing at what we would call

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a a quarter moon if you were imagining.

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The analog of the moon around the earth.

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And so you see some,

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radiation, some thermal emission from the planet and

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some from the star, You have to be

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able to subtract the light from the star

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and you do that by getting those measurements

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when the planet goes behind the star. So

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you take measurements to different times and difference

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them.

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And this allows you to not only see

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the actual emitted spectrum, but to actually see

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how that spectrum changes

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as the planet completes its orbit.

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And and it would change because the the

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temperature of the of the planet is changing.

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Is that, could you actually see that? Yeah.

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Not just the temperature, but you can you

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can see that the chemistry then changes because

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the temperature is changing, so you have different...

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Atoms or molecules that might be present,

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and we can actually see wins. We can

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actually see

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the... There's evidence that

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you know, the heated gas from the day

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side of the planet is flowing around to

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the night side of the planet. So,

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you know, when the data are up high

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quality, we get access to a lot of

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the dynamics

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and the chemistry

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of of the planetary atmosphere.

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Wow. I mean, that is incredible when you

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consider how far away these things are. So

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David, using these techniques, what have we learned

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so far about exoplanet atmospheres.

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Well, in in many ways, we've learned

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a great deal,

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And in many ways, we've learned almost nothing,

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and there's and there's a very exciting future

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in front of us.

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For certain kinds of planets,

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and in particular for what we call the

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hot jupiter,

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we've had access to a very rich data

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set, and that's simply because they're the easiest

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to study.

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Okay? So the hot jupiter, as you might

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imagine, are both the physically the largest planets

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that are out there, but they're also the

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hottest ones.

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And so when they pass in front of

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their star,

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their

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atmosphere, that ann that you're viewing in transmission

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that ring of atmosphere,

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is very large, both because the planet is

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large and because the atmosphere is puffy because

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the atmosphere is hot.

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And so in in that case, we've been

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able to

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detect many molecules. So the first detection was

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00:10:16,860 --> 00:10:17,736
sodium atom,

277
00:10:18,629 --> 00:10:20,970
but we now have been able to detect

278
00:10:21,350 --> 00:10:21,750
water,

279
00:10:22,230 --> 00:10:23,509
a carbon dioxide,

280
00:10:24,629 --> 00:10:26,329
carbon dioxide, methane,

281
00:10:27,603 --> 00:10:28,103
and

282
00:10:28,554 --> 00:10:31,091
now we're seeing evidence of photo chemistry. We're

283
00:10:31,091 --> 00:10:33,890
actually seeing products that we would only expect

284
00:10:34,104 --> 00:10:36,829
due to this specific interaction of the radiation,

285
00:10:37,070 --> 00:10:39,789
changing the actual chemistry of the atmosphere rather

286
00:10:39,789 --> 00:10:41,870
than just the atmosphere being hot. Okay?

287
00:10:43,404 --> 00:10:45,160
And as I mentioned, we can also make

288
00:10:45,160 --> 00:10:47,155
maps of the planets. So for these hot

289
00:10:47,155 --> 00:10:47,634
jupiter,

290
00:10:48,193 --> 00:10:50,188
we can actually measure the thermal emission as

291
00:10:50,188 --> 00:10:52,359
they orbit around their star. And we can

292
00:10:52,359 --> 00:10:54,197
see to what extent some of the planets

293
00:10:54,197 --> 00:10:57,153
are able to take the the the radiation

294
00:10:57,153 --> 00:10:59,171
that's dumped onto to the hot bay side

295
00:10:59,231 --> 00:11:01,161
because we think most of these Planets are

296
00:11:01,161 --> 00:11:03,231
tit locked. They always present the same face

297
00:11:03,231 --> 00:11:04,983
to the star, and we can see that

298
00:11:04,983 --> 00:11:07,053
red distributed around to the night side. The

299
00:11:07,053 --> 00:11:08,965
night side is not cold. Is my point.

300
00:11:09,139 --> 00:11:10,566
The night side is a little bit colder,

301
00:11:11,280 --> 00:11:13,343
but it's not it's not perfectly cold, and

302
00:11:13,343 --> 00:11:15,509
that indicates that some heat is being transported.

303
00:11:16,772 --> 00:11:18,924
And and there's of course, this incredibly rich

304
00:11:18,924 --> 00:11:20,758
dataset set now coming out of the James

305
00:11:20,758 --> 00:11:24,287
webb space telescope, which is really unprecedented,

306
00:11:24,839 --> 00:11:26,536
both in terms of its

307
00:11:26,914 --> 00:11:28,591
aperture. Okay. I can collect a lot of

308
00:11:28,591 --> 00:11:30,666
light during these very special moments. There's only

309
00:11:30,666 --> 00:11:32,103
a few hours when the planet goes in

310
00:11:32,103 --> 00:11:33,061
front of the star, we have to get

311
00:11:33,061 --> 00:11:34,909
as much data as we can,

312
00:11:35,946 --> 00:11:38,178
but it's also very sensitive to infrared wavelengths.

313
00:11:38,417 --> 00:11:40,808
And most molecules, of course, are active. We

314
00:11:40,808 --> 00:11:44,274
see their features at infrared wavelengths. And so

315
00:11:44,413 --> 00:11:46,328
the James Webb space telescope is really, very,

316
00:11:46,487 --> 00:11:49,200
very special. Okay. So that's the good news.

317
00:11:49,772 --> 00:11:53,129
The bad news is that for the smaller

318
00:11:53,422 --> 00:11:56,437
rocky planets, planets like the Earth and venus.

319
00:11:57,246 --> 00:12:00,502
We know essentially nothing, and that is because

320
00:12:00,502 --> 00:12:01,875
the atmospheres are,

321
00:12:02,408 --> 00:12:05,425
tiny, and the atmospheres are colder compared to

322
00:12:05,425 --> 00:12:07,749
the hot Jupiter. And so we just don't

323
00:12:07,749 --> 00:12:08,967
yet have the sensitivity.

324
00:12:09,663 --> 00:12:11,757
Now, for certain systems,

325
00:12:12,134 --> 00:12:14,287
we are able to begin those studies.

326
00:12:15,179 --> 00:12:18,539
And those are for small stars, which astronomers

327
00:12:18,539 --> 00:12:20,299
call red dwarf or m dwarf.

328
00:12:21,019 --> 00:12:22,539
And by shrinking the star,

329
00:12:23,195 --> 00:12:25,115
Okay? We... We're shrinking some of the noise

330
00:12:25,115 --> 00:12:26,795
that we're trying to overcome. The bright light

331
00:12:26,795 --> 00:12:28,955
of the star is something that we have

332
00:12:28,955 --> 00:12:30,154
to to manage.

333
00:12:30,649 --> 00:12:32,503
Okay? It allows us to probe the planetary

334
00:12:32,640 --> 00:12:34,073
atmosphere, but it also causes a lot of

335
00:12:34,073 --> 00:12:35,029
noise in our measurements.

336
00:12:35,666 --> 00:12:37,418
And so when we find these small Rocky

337
00:12:37,418 --> 00:12:39,170
planets orbiting these m dwarf.

338
00:12:39,903 --> 00:12:42,376
Then we can access them if the M

339
00:12:42,376 --> 00:12:44,610
dwarf planets are also very hot. And so

340
00:12:44,610 --> 00:12:45,509
there's a few

341
00:12:45,887 --> 00:12:46,387
systems,

342
00:12:47,098 --> 00:12:49,722
where the data are very good, and we've

343
00:12:49,722 --> 00:12:51,550
actually learned they don't have an atmosphere.

344
00:12:52,425 --> 00:12:54,945
So they might be similar to to

345
00:12:55,303 --> 00:12:57,397
mercury in our own solar system where Mercury

346
00:12:57,455 --> 00:13:00,086
because it's hot and relatively low mass was

347
00:13:00,086 --> 00:13:01,919
not able to retain its atmosphere. And so

348
00:13:01,919 --> 00:13:03,035
that's really exciting.

349
00:13:03,529 --> 00:13:05,766
We're now at the point of probing what

350
00:13:05,766 --> 00:13:07,305
the astronomers call the cosmic

351
00:13:07,684 --> 00:13:10,820
shoreline. We're trying to figure out how cold

352
00:13:11,213 --> 00:13:12,031
and how

353
00:13:12,565 --> 00:13:14,871
how massive does a rocky planet it have

354
00:13:14,871 --> 00:13:17,495
to be when we first see it it

355
00:13:17,495 --> 00:13:19,656
it's able to retain that at... Sphere as

356
00:13:19,656 --> 00:13:21,959
opposed to losing it entirely, which, of course,

357
00:13:22,118 --> 00:13:24,660
puts it on a completely different path both

358
00:13:24,660 --> 00:13:27,123
for its evolution and also for the prospects

359
00:13:27,123 --> 00:13:30,243
of potentially hosting life. So And in in

360
00:13:30,243 --> 00:13:33,359
your research, looking at atmospheres. What is there

361
00:13:33,359 --> 00:13:36,475
1 thing that has surprised you the most?

362
00:13:37,209 --> 00:13:39,606
In terms of you know, what you've learned

363
00:13:39,606 --> 00:13:40,725
about Exoplanet,

364
00:13:41,524 --> 00:13:43,042
atmospheres or is, is it is there a

365
00:13:43,042 --> 00:13:45,120
new surprise every day for you?

366
00:13:45,855 --> 00:13:47,475
Well, I would say the,

367
00:13:47,934 --> 00:13:48,894
you know, the story...

368
00:13:49,375 --> 00:13:50,894
When you work in Exoplanets, you sort of

369
00:13:50,894 --> 00:13:52,014
have to get used to surprises.

370
00:13:52,575 --> 00:13:54,495
Right? Because as Sarah was describing,

371
00:13:54,989 --> 00:13:56,581
just in terms of the population of planets,

372
00:13:57,138 --> 00:13:59,208
most of the planets that we know about

373
00:13:59,208 --> 00:14:00,026
orbiting other

374
00:14:00,402 --> 00:14:02,790
stars have no analog in the solar system.

375
00:14:03,442 --> 00:14:06,328
Okay? They're intermediate and size between earth

376
00:14:06,783 --> 00:14:09,169
and, you know, neptune. Okay? We don't have

377
00:14:09,169 --> 00:14:11,169
anything like that. In our solar system,

378
00:14:12,121 --> 00:14:14,738
and yet most planets that we've discovered are

379
00:14:14,738 --> 00:14:17,355
are in that in that middle zone. And

380
00:14:17,355 --> 00:14:17,855
so,

381
00:14:18,803 --> 00:14:21,301
then, you know, pretty much by definition, their

382
00:14:21,360 --> 00:14:23,198
atmospheres and their properties are are also gonna

383
00:14:23,198 --> 00:14:23,698
be

384
00:14:24,317 --> 00:14:25,515
complete surprises.

385
00:14:26,089 --> 00:14:28,389
So I I would say that learning about

386
00:14:28,389 --> 00:14:30,134
the atmospheres of those planets,

387
00:14:30,927 --> 00:14:32,752
which are sometimes called water worlds.

388
00:14:33,324 --> 00:14:35,878
Or mini neptune or super and that just

389
00:14:35,878 --> 00:14:37,155
reflects the fact that we don't know what

390
00:14:37,155 --> 00:14:39,470
the heck really are. That will tell us

391
00:14:39,470 --> 00:14:41,466
their true identities. That will tell us whether

392
00:14:41,466 --> 00:14:43,898
they really are more similar to Neptune

393
00:14:44,277 --> 00:14:46,835
or more similar to to the earth with

394
00:14:46,835 --> 00:14:49,472
maybe some hydrogen on top. So so that's

395
00:14:49,472 --> 00:14:51,310
sort of a surprise I would say in

396
00:14:51,310 --> 00:14:51,630
waiting.

397
00:14:52,443 --> 00:14:53,081
So Sarah,

398
00:14:53,720 --> 00:14:56,752
observing signs of life on an exoplanet would

399
00:14:56,752 --> 00:14:59,785
be a profound event for humanity.

400
00:15:00,438 --> 00:15:01,734
What are the bios

401
00:15:02,588 --> 00:15:05,535
that astronomers like you are are looking for?

402
00:15:06,412 --> 00:15:08,482
It turns out this is an incredibly loaded

403
00:15:08,482 --> 00:15:08,881
question.

404
00:15:09,531 --> 00:15:12,782
And as we unfold the observations and get

405
00:15:12,782 --> 00:15:14,074
closer to the day

406
00:15:14,447 --> 00:15:16,532
when making such a

407
00:15:17,397 --> 00:15:20,342
detection becomes reality. It's just incredibly messy.

408
00:15:21,854 --> 00:15:24,973
So we've worked like microbe in particular, over

409
00:15:24,973 --> 00:15:26,804
the last couple decades to literally come up

410
00:15:26,804 --> 00:15:29,670
with a list of every molecule that's in

411
00:15:29,670 --> 00:15:30,568
gas phase

412
00:15:31,182 --> 00:15:33,267
at a habitable world temperature impression and there's

413
00:15:33,267 --> 00:15:35,019
a lot of them. There's, like 14000. I

414
00:15:35,019 --> 00:15:36,315
mean, large majority are

415
00:15:36,690 --> 00:15:39,397
compounds, but... And we've kind of worked through

416
00:15:39,397 --> 00:15:41,958
classes of molecules or... You know, other people

417
00:15:41,958 --> 00:15:43,549
are growing group of people work on this

418
00:15:43,549 --> 00:15:44,026
as well.

419
00:15:44,901 --> 00:15:46,810
The reason I'm hesitating to give a direct

420
00:15:46,810 --> 00:15:46,969
answer,

421
00:15:47,939 --> 00:15:50,269
is because we will be faced with 3

422
00:15:50,406 --> 00:15:53,191
incredibly important questions. 1 is the signal real.

423
00:15:54,624 --> 00:15:56,534
Any gas we're looking for is likely to

424
00:15:56,534 --> 00:15:59,091
be a trace gas not there at huge

425
00:15:59,091 --> 00:15:59,488
quantities.

426
00:16:00,759 --> 00:16:03,140
Second 1 is the signal attributed to the

427
00:16:03,140 --> 00:16:03,696
right molecule.

428
00:16:04,172 --> 00:16:06,572
And then the third question assuming the first

429
00:16:06,572 --> 00:16:09,378
2 pass some bar is the molecule

430
00:16:09,753 --> 00:16:11,026
produced by life or does it have an

431
00:16:11,026 --> 00:16:12,060
antibiotic false positive?

432
00:16:12,871 --> 00:16:15,359
So what we've largely found is that for

433
00:16:15,655 --> 00:16:18,143
nearly every gas of interest, there are multiple

434
00:16:18,200 --> 00:16:18,837
options for...

435
00:16:19,726 --> 00:16:21,816
For how to assign the gas, and

436
00:16:22,429 --> 00:16:24,814
it's gonna be a tricky situation. My favorite

437
00:16:24,814 --> 00:16:27,596
gas personally, is so oxygen. Oxygen is a

438
00:16:27,596 --> 00:16:29,997
highly reactive gas shouldn't be in our atmosphere

439
00:16:29,997 --> 00:16:32,224
unless it's continually produced. I mean, there are

440
00:16:32,224 --> 00:16:34,928
ways to Produce oxygen without life. And our

441
00:16:34,928 --> 00:16:37,727
telescope the James webb space telescope isn't... Quite

442
00:16:37,727 --> 00:16:40,275
capable of detecting oxygen right now. But we

443
00:16:40,275 --> 00:16:41,628
have a huge list of other gases,

444
00:16:42,504 --> 00:16:45,392
and those include pho. They include

445
00:16:45,943 --> 00:16:48,517
you know, dime cell. There's literally

446
00:16:49,134 --> 00:16:50,808
a good long list of molecules we're are

447
00:16:50,808 --> 00:16:51,207
interested in?

448
00:16:52,244 --> 00:16:54,318
And how do you sort of get away

449
00:16:54,318 --> 00:16:56,881
from the the sort of earth and and

450
00:16:56,881 --> 00:16:59,664
solar system bias when you're coming up with

451
00:16:59,664 --> 00:17:00,164
lists

452
00:17:00,697 --> 00:17:03,003
of chemicals to look for. Or you you

453
00:17:03,003 --> 00:17:03,615
have to be

454
00:17:04,052 --> 00:17:05,188
very imaginative

455
00:17:05,642 --> 00:17:07,948
in terms of what sort of life you're

456
00:17:07,948 --> 00:17:08,448
imagining

457
00:17:08,823 --> 00:17:11,129
on a distant planet. Well, we aren't able

458
00:17:11,129 --> 00:17:12,560
to go from what the life is to

459
00:17:12,560 --> 00:17:14,801
what it will produce. We're just making the

460
00:17:14,801 --> 00:17:17,345
assumption that life elsewhere like life on earth

461
00:17:17,345 --> 00:17:19,570
should use chemistry to extract energy from the

462
00:17:19,570 --> 00:17:20,762
environment to store energy.

463
00:17:21,414 --> 00:17:23,727
And to metabolize and in the process produce

464
00:17:23,727 --> 00:17:24,525
a waste gas.

465
00:17:25,163 --> 00:17:27,077
So we're sticking with this general idea that

466
00:17:27,077 --> 00:17:28,911
there should be a gas that doesn't belong

467
00:17:28,911 --> 00:17:31,065
that's far out of equilibrium with its environment.

468
00:17:32,200 --> 00:17:33,019
And so

469
00:17:33,720 --> 00:17:36,359
there's no magic bullet, basically. That's why I

470
00:17:36,359 --> 00:17:37,960
started by saying that we've tried to come

471
00:17:37,960 --> 00:17:39,099
with a list of all molecules

472
00:17:39,493 --> 00:17:41,642
of interests, literally, like, whether or not they're

473
00:17:41,642 --> 00:17:43,791
produced by life on earth. And and when

474
00:17:43,791 --> 00:17:45,463
you're doing this research, I mean, do you

475
00:17:45,463 --> 00:17:46,816
work with Chemists?

476
00:17:47,387 --> 00:17:50,251
Who who addressed this problem. I suppose from

477
00:17:50,251 --> 00:17:52,001
a from a chemical point of view. Is

478
00:17:52,001 --> 00:17:54,069
that... Is that a part of your sort

479
00:17:54,069 --> 00:17:56,312
of day to day research? I do have

480
00:17:56,312 --> 00:17:57,508
bio on my team,

481
00:17:58,305 --> 00:18:00,217
but it's not really necessary at this point

482
00:18:00,217 --> 00:18:01,652
because we're still at that point of trying

483
00:18:01,652 --> 00:18:03,700
to detect trying to assign the molecule and

484
00:18:03,818 --> 00:18:05,561
trying to believe if the signals real or

485
00:18:05,561 --> 00:18:08,255
not. So, Sarah, a growing number of earth

486
00:18:08,255 --> 00:18:10,553
like exoplanets are being discovered.

487
00:18:11,364 --> 00:18:13,917
Are these the only places where astronomers are

488
00:18:13,917 --> 00:18:16,710
looking for signs of life or could life

489
00:18:16,710 --> 00:18:19,675
exist on other types of Exoplanets? That's a

490
00:18:19,675 --> 00:18:21,740
great question. Let's call them at earth size

491
00:18:21,740 --> 00:18:23,090
because we don't know if they're earth like

492
00:18:23,090 --> 00:18:23,249
yet.

493
00:18:24,044 --> 00:18:25,950
And, you know, it's just so hard as

494
00:18:26,029 --> 00:18:28,669
Dave was sane and earth... Sized planet likely

495
00:18:28,669 --> 00:18:31,138
has a tiny atmosphere. Think of like the

496
00:18:31,138 --> 00:18:32,572
skin of an onion on an onion.

497
00:18:33,688 --> 00:18:34,245
So tiny.

498
00:18:35,374 --> 00:18:37,442
So it's kind of like the person looking

499
00:18:37,442 --> 00:18:40,465
for their lost keys and looking under the

500
00:18:40,465 --> 00:18:40,942
street lamp.

501
00:18:42,554 --> 00:18:43,835
That's what we're kind of trying to do.

502
00:18:43,994 --> 00:18:45,835
We're trying to broaden our perspectives so we

503
00:18:45,835 --> 00:18:47,375
have a better chance to find

504
00:18:48,154 --> 00:18:48,714
signs of life.

505
00:18:49,688 --> 00:18:51,677
So the next, you know, biggest type of

506
00:18:51,677 --> 00:18:53,667
planet are these so called mini neptune, and

507
00:18:53,667 --> 00:18:55,179
there's 2 thrust going on there.

508
00:18:55,816 --> 00:18:57,820
1 is an idea that like Earth has

509
00:18:57,820 --> 00:18:59,570
an aerial biosphere here. We have life in

510
00:18:59,570 --> 00:19:00,047
our clouds.

511
00:19:00,922 --> 00:19:02,832
Perhaps there's life in the clouds and other

512
00:19:02,832 --> 00:19:03,150
planets.

513
00:19:04,199 --> 00:19:06,113
And these mini neptune, the ones we can

514
00:19:06,113 --> 00:19:07,946
access now. They're typically too hot at their

515
00:19:07,946 --> 00:19:10,338
surface for life. But in the clouds, just

516
00:19:10,338 --> 00:19:11,773
like on earth as you go up into

517
00:19:11,773 --> 00:19:13,785
the clouds the atmosphere gets. Cooler, so to

518
00:19:13,785 --> 00:19:16,664
on other planets. So there's that idea, but,

519
00:19:16,744 --> 00:19:18,585
you know, people have had that idea before

520
00:19:18,585 --> 00:19:20,505
for Jupiter, like Carl Saga tried to propose.

521
00:19:20,664 --> 00:19:22,438
There could be life on Jupiter, and in

522
00:19:22,438 --> 00:19:24,352
that situation, if the surface is too hot,

523
00:19:24,512 --> 00:19:26,107
we you have to just have a kind

524
00:19:26,107 --> 00:19:28,659
of con confined scenario where the down drafts

525
00:19:28,659 --> 00:19:30,892
wouldn't bring life too far downwards too hot.

526
00:19:32,104 --> 00:19:32,604
Others

527
00:19:33,381 --> 00:19:35,775
take this idea of the so called mini...

528
00:19:35,935 --> 00:19:37,851
The many neptune being so called water worlds.

529
00:19:38,489 --> 00:19:40,539
And, you know, there are some scenarios where

530
00:19:40,978 --> 00:19:43,851
the water world may literally have a liquid

531
00:19:43,851 --> 00:19:47,043
water ocean, a hot water ocean. Maybe not

532
00:19:47,043 --> 00:19:48,421
too hot for life, but

533
00:19:48,894 --> 00:19:50,332
so hot and that there might be life

534
00:19:50,332 --> 00:19:52,089
in those oceans. So we're literally,

535
00:19:52,569 --> 00:19:54,965
maybe even pushing the pendulum too far, maybe

536
00:19:54,965 --> 00:19:56,812
not. But we're trying to be as open

537
00:19:56,812 --> 00:19:58,482
as possible so we don't miss our chance

538
00:19:58,482 --> 00:20:00,494
to find signs of life with our current

539
00:20:00,710 --> 00:20:01,823
James webb telescope.

540
00:20:02,794 --> 00:20:05,047
And and, Sir, what's your your sort of

541
00:20:05,184 --> 00:20:07,257
overall view on the existence of life?

542
00:20:08,213 --> 00:20:10,047
I mean, do you think that life must?

543
00:20:11,016 --> 00:20:13,080
Occur out there somewhere. It would just be

544
00:20:13,080 --> 00:20:13,580
a

545
00:20:13,953 --> 00:20:15,961
almost a mathematical impossibility

546
00:20:16,334 --> 00:20:17,230
that it didn't

547
00:20:17,604 --> 00:20:20,255
or you know, is it possible that Earth

548
00:20:20,255 --> 00:20:22,654
is the only place in the... Well, at

549
00:20:22,654 --> 00:20:25,855
least in the near universe where life exists.

550
00:20:26,348 --> 00:20:28,284
Well, since it's a physics podcast,

551
00:20:29,060 --> 00:20:31,474
we really couldn't answer that question

552
00:20:31,932 --> 00:20:34,325
in any way quantitatively until we better understand

553
00:20:34,325 --> 00:20:35,601
the origin of life on earth. You know,

554
00:20:35,680 --> 00:20:38,502
we have giant holes in our in our

555
00:20:38,558 --> 00:20:40,944
understanding of how life on earth arose, but

556
00:20:40,944 --> 00:20:42,613
just speculating for a moment,

557
00:20:43,408 --> 00:20:45,317
we see the ingredients for life everywhere. You

558
00:20:45,317 --> 00:20:45,476
know,

559
00:20:46,127 --> 00:20:48,595
meteorites have amino acids. We see all kinds

560
00:20:48,595 --> 00:20:50,825
of complex organic molecules in the intra interstellar

561
00:20:50,825 --> 00:20:52,894
medium. That doesn't mean they survive when they

562
00:20:52,894 --> 00:20:53,611
make it to a planet.

563
00:20:54,262 --> 00:20:56,328
But it seems like the ingredients for life

564
00:20:56,328 --> 00:20:59,189
are quite straightforward to form. And just given

565
00:20:59,189 --> 00:21:01,096
the number of stars in our galaxy alone,

566
00:21:01,335 --> 00:21:02,686
hundreds of billions of stars.

567
00:21:03,179 --> 00:21:06,135
And the idea, a reality that there are

568
00:21:06,135 --> 00:21:08,532
hundreds of billions of galaxies out there. Surely

569
00:21:08,532 --> 00:21:09,570
there is life elsewhere.

570
00:21:10,304 --> 00:21:12,460
But the question we're facing right now, Dave

571
00:21:12,460 --> 00:21:14,296
and I and all the others working on

572
00:21:14,695 --> 00:21:15,094
Exoplanets is,

573
00:21:15,972 --> 00:21:17,968
is there life on a planet orbiting a

574
00:21:17,968 --> 00:21:19,820
star near enough and right enough, for us

575
00:21:19,820 --> 00:21:21,019
to find a sign now.

576
00:21:22,059 --> 00:21:23,900
And finding a sign of life now doesn't

577
00:21:23,900 --> 00:21:25,259
mean we'll be sure there's life out there,

578
00:21:25,500 --> 00:21:27,854
but it means it'll be enough for to

579
00:21:27,994 --> 00:21:29,672
fuel the search to keep going.

580
00:21:30,951 --> 00:21:33,108
And, Sarah, is there always going to be

581
00:21:33,108 --> 00:21:33,928
some sort of

582
00:21:34,627 --> 00:21:36,625
ambiguity involved in these measurements?

583
00:21:36,959 --> 00:21:39,195
You know, you might have... You might see

584
00:21:39,195 --> 00:21:40,174
lots of bios,

585
00:21:40,791 --> 00:21:43,107
but maybe at the end of the day,

586
00:21:43,266 --> 00:21:44,565
they could all have

587
00:21:45,182 --> 00:21:46,162
non biological

588
00:21:46,874 --> 00:21:49,104
origins, and, you know, you can never say,

589
00:21:49,662 --> 00:21:52,450
u, a hundred percent that there's life on

590
00:21:52,450 --> 00:21:52,769
that

591
00:21:53,326 --> 00:21:53,565
Exoplanet.

592
00:21:54,219 --> 00:21:56,773
There will always be an ambiguity with remote

593
00:21:56,773 --> 00:21:57,172
sensing.

594
00:21:57,810 --> 00:22:00,125
Some people have tried to put forward an

595
00:22:00,125 --> 00:22:01,721
idea that if you do see lots, you

596
00:22:01,721 --> 00:22:02,461
know, every

597
00:22:02,853 --> 00:22:04,760
planet that could have water has signs of

598
00:22:04,760 --> 00:22:07,461
water and signs of life that that, you

599
00:22:07,461 --> 00:22:08,279
know, collective

600
00:22:10,338 --> 00:22:12,651
set of observations may indicate there's life out

601
00:22:12,651 --> 00:22:14,645
there. But let's not get ahead of ourselves.

602
00:22:14,884 --> 00:22:16,559
We're living in an amazing time. We have

603
00:22:16,559 --> 00:22:17,617
over 5000

604
00:22:17,915 --> 00:22:19,590
exoplanets. We know that rocky planets,

605
00:22:20,404 --> 00:22:22,481
Our common, we know that planets of all

606
00:22:22,481 --> 00:22:23,941
kinds in their habitable zone

607
00:22:24,320 --> 00:22:25,918
are out there, and we're on the verge

608
00:22:25,918 --> 00:22:27,676
of being able to find water vapor on

609
00:22:27,676 --> 00:22:28,475
habitable planets.

610
00:22:29,128 --> 00:22:30,882
Maybe some hints of signs of life that

611
00:22:30,882 --> 00:22:33,034
will keep us moving forward. And and what

612
00:22:33,034 --> 00:22:33,512
about

613
00:22:34,070 --> 00:22:36,063
you know, your your research and the research

614
00:22:36,063 --> 00:22:36,802
of others

615
00:22:37,434 --> 00:22:40,706
into how life could exist on other planets.

616
00:22:40,865 --> 00:22:44,558
Is is that informing in any way our

617
00:22:44,696 --> 00:22:47,585
understanding of of life on earth? Are we

618
00:22:47,585 --> 00:22:49,261
more open to...

619
00:22:49,900 --> 00:22:50,958
I don't know looking

620
00:22:52,214 --> 00:22:54,784
in, you know, places on earth where we

621
00:22:54,784 --> 00:22:56,625
might have thought life couldn't exist,

622
00:22:57,744 --> 00:22:59,184
but, you know, maybe it could.

623
00:23:00,224 --> 00:23:02,304
I would have to say not yet to

624
00:23:02,304 --> 00:23:04,637
that. You know, and earth people have looked

625
00:23:04,637 --> 00:23:07,194
literally every everywhere they can for life, like,

626
00:23:07,273 --> 00:23:09,351
in the dries deserts and the most acidic

627
00:23:09,351 --> 00:23:09,830
environments.

628
00:23:10,482 --> 00:23:12,387
And so that research kind of goes on

629
00:23:12,387 --> 00:23:13,102
in parallel.

630
00:23:13,737 --> 00:23:15,665
We always like to hope though that studying

631
00:23:15,721 --> 00:23:18,658
exoplanets, the search for life or exoplanets themselves

632
00:23:18,658 --> 00:23:19,109
will

633
00:23:19,863 --> 00:23:20,601
feedback onto

634
00:23:21,530 --> 00:23:23,117
our understanding of our own planet, and it

635
00:23:23,117 --> 00:23:25,973
might well 1 day. So looking towards the

636
00:23:25,973 --> 00:23:29,438
future. What new telescopes are are you both

637
00:23:29,577 --> 00:23:32,609
most excited about? And why? David, do you

638
00:23:32,609 --> 00:23:35,259
wanna go first with your answer? I think

639
00:23:35,259 --> 00:23:37,839
the news here is that there are some

640
00:23:37,980 --> 00:23:39,039
incredibly powerful

641
00:23:40,140 --> 00:23:40,640
ob

642
00:23:41,500 --> 00:23:41,954
that

643
00:23:42,472 --> 00:23:43,768
will be coming online

644
00:23:44,143 --> 00:23:45,837
and are gonna probe

645
00:23:46,690 --> 00:23:48,145
regions of parameter space

646
00:23:48,520 --> 00:23:49,577
that have been

647
00:23:49,888 --> 00:23:50,388
previously

648
00:23:50,839 --> 00:23:53,772
inaccessible to to study. Okay? So it's a

649
00:23:53,772 --> 00:23:54,906
tremendously exciting

650
00:23:56,785 --> 00:23:56,943
future.

651
00:23:58,230 --> 00:24:00,163
The next big mission

652
00:24:00,539 --> 00:24:03,484
that will advance our understanding of Exoplanets is

653
00:24:03,484 --> 00:24:05,178
called the Nancy Grace Roman

654
00:24:05,569 --> 00:24:07,727
telescope. It's a Nasa facility.

655
00:24:08,606 --> 00:24:11,003
And so what it will do is it

656
00:24:11,003 --> 00:24:11,723
will do

657
00:24:12,122 --> 00:24:14,360
a micro lens survey. So that's a different

658
00:24:14,360 --> 00:24:18,286
method that allows us to find planets that

659
00:24:18,286 --> 00:24:20,042
are very, very far from their stars.

660
00:24:20,920 --> 00:24:23,965
The the most successful methods to date Namely

661
00:24:23,965 --> 00:24:26,113
the transit method when planets pass in front

662
00:24:26,113 --> 00:24:28,738
of their star and the wobble method when

663
00:24:28,738 --> 00:24:31,856
there's the gravitational orbit of the of the

664
00:24:31,856 --> 00:24:33,846
star and the planet around their common center

665
00:24:33,846 --> 00:24:36,870
of mass, those both favor close end planets.

666
00:24:37,507 --> 00:24:39,779
But if you were trying to understand the

667
00:24:39,919 --> 00:24:41,759
formation of the solar system and all you

668
00:24:41,759 --> 00:24:43,919
knew about where the inner planets, you'd probably

669
00:24:43,919 --> 00:24:46,329
have a very incomplete theory. So we really

670
00:24:46,329 --> 00:24:48,314
need to know about Saturn and uranus and

671
00:24:48,314 --> 00:24:48,711
neptune,

672
00:24:49,267 --> 00:24:51,490
and how common those are around other stars.

673
00:24:51,887 --> 00:24:53,609
And so I'm very, very excited about that

674
00:24:53,808 --> 00:24:55,710
that mission which will hopefully launch in just

675
00:24:55,710 --> 00:24:56,423
a few years.

676
00:24:58,325 --> 00:24:59,118
After that,

677
00:24:59,673 --> 00:25:00,965
the next big project

678
00:25:01,274 --> 00:25:03,585
will be on the ground, and it will

679
00:25:03,585 --> 00:25:03,824
be,

680
00:25:05,338 --> 00:25:06,635
a class of telescope

681
00:25:07,330 --> 00:25:08,787
called the extremely large

682
00:25:09,099 --> 00:25:11,254
telescopes, and there's 3 of them. They're being

683
00:25:11,254 --> 00:25:13,569
built by different nations and different cons consortium.

684
00:25:14,367 --> 00:25:15,485
But they will have,

685
00:25:15,964 --> 00:25:18,769
a tremendous aperture, basically be much larger than

686
00:25:18,769 --> 00:25:21,469
any ground based telescope that operates in the

687
00:25:21,469 --> 00:25:23,058
optical and and for it has ever been.

688
00:25:23,773 --> 00:25:24,726
And they will,

689
00:25:25,440 --> 00:25:26,496
allow us to gather

690
00:25:26,950 --> 00:25:29,028
more photon. More light than we never been

691
00:25:29,028 --> 00:25:31,489
able to do and really study these atmospheres

692
00:25:31,489 --> 00:25:33,236
at very high spectral resolution.

693
00:25:34,188 --> 00:25:36,013
And so they might allow us to really

694
00:25:36,013 --> 00:25:36,545
study. It's

695
00:25:37,305 --> 00:25:39,965
the the specific chemistry of these atmospheres

696
00:25:40,345 --> 00:25:41,725
and really go after

697
00:25:42,105 --> 00:25:43,945
potentially even some of these some of these

698
00:25:43,945 --> 00:25:44,445
bios

699
00:25:45,305 --> 00:25:45,805
molecules,

700
00:25:46,837 --> 00:25:47,395
as well.

701
00:25:48,432 --> 00:25:50,666
And so those might be coming online in

702
00:25:50,666 --> 00:25:51,325
the next

703
00:25:51,702 --> 00:25:53,617
well, I would say 5 to 10 years.

704
00:25:54,574 --> 00:25:55,553
And then finally,

705
00:25:56,423 --> 00:25:58,755
that the next big Nasa emission

706
00:25:59,927 --> 00:26:02,418
is called the habitable worlds observatory.

707
00:26:02,794 --> 00:26:04,467
And so that's that's sort of a working

708
00:26:04,467 --> 00:26:06,468
name So III

709
00:26:06,468 --> 00:26:07,659
anticipate that when it launches,

710
00:26:08,532 --> 00:26:11,391
maybe 15 years from now, it will be

711
00:26:11,391 --> 00:26:14,034
given a different name. But it will

712
00:26:14,423 --> 00:26:16,913
really allow us to study the atmospheres

713
00:26:17,288 --> 00:26:18,345
of earth

714
00:26:18,721 --> 00:26:21,847
like planets orbiting sun like stars. So real

715
00:26:22,318 --> 00:26:25,271
twins we hope of the Earth's sun system.

716
00:26:25,670 --> 00:26:29,021
I mentioned before that the only rocky planets

717
00:26:29,021 --> 00:26:30,868
who's at spheres, we can hope to study

718
00:26:30,868 --> 00:26:32,780
in the near future are the ones that

719
00:26:32,780 --> 00:26:35,089
orbit these low mass stars, these these red

720
00:26:35,089 --> 00:26:35,726
dwarf stars.

721
00:26:36,443 --> 00:26:39,326
But maybe there's something about those kinds of

722
00:26:39,326 --> 00:26:41,956
stars that preclude the existence of life. Maybe

723
00:26:41,956 --> 00:26:44,108
they put out too much uv light. Maybe

724
00:26:44,108 --> 00:26:45,942
they always strip away the atmospheres of their

725
00:26:45,942 --> 00:26:48,027
planets we're gonna find that out over the

726
00:26:48,027 --> 00:26:48,664
next 5 years.

727
00:26:49,699 --> 00:26:51,711
So that's why it's important that we simultaneously

728
00:26:52,723 --> 00:26:54,529
pursue this other path

729
00:26:54,887 --> 00:26:56,817
where we are building the technology

730
00:26:57,270 --> 00:27:00,289
to really look at the atmospheres of Earth

731
00:27:00,289 --> 00:27:01,504
sun analog.

732
00:27:02,293 --> 00:27:02,793
And

733
00:27:03,170 --> 00:27:05,483
that's why the habitable world observatory, which will

734
00:27:05,483 --> 00:27:07,796
be able to spatial isolate the planets and

735
00:27:07,796 --> 00:27:10,348
actually see the reflected light and do spectroscopy

736
00:27:10,348 --> 00:27:11,226
on that reflected light.

737
00:27:11,960 --> 00:27:15,000
That's gonna be really, really demanding technologically,

738
00:27:15,320 --> 00:27:16,680
but I know that, you know, the community's

739
00:27:16,680 --> 00:27:18,519
is up to the task. And, of course,

740
00:27:18,680 --> 00:27:18,920
the,

741
00:27:20,532 --> 00:27:22,830
the idea of having having access to this

742
00:27:22,830 --> 00:27:25,287
really profound question is is what drives us

743
00:27:25,287 --> 00:27:26,317
all forward.

744
00:27:27,918 --> 00:27:29,612
1 question we have

745
00:27:30,543 --> 00:27:32,157
back to your earlier

746
00:27:32,850 --> 00:27:33,884
question and the con is,

747
00:27:34,854 --> 00:27:36,532
are we too t centric When we go

748
00:27:36,532 --> 00:27:38,929
out there with the Habitable world observatory, will

749
00:27:38,929 --> 00:27:40,448
we find earth like worlds?

750
00:27:41,167 --> 00:27:42,525
Or will they be all like venus?

751
00:27:43,258 --> 00:27:44,056
Or something else.

752
00:27:45,172 --> 00:27:47,005
And I've just spent a few years on

753
00:27:47,005 --> 00:27:48,998
what started out as this tangent that has

754
00:27:48,998 --> 00:27:49,498
grown

755
00:27:49,954 --> 00:27:51,070
into my favorite mission,

756
00:27:51,884 --> 00:27:54,681
which is this consortium I'm leading, we call

757
00:27:54,681 --> 00:27:57,158
ourselves the mornings star missions to venus.

758
00:27:57,717 --> 00:27:59,555
We're going to be a series of private

759
00:27:59,555 --> 00:27:59,875
public,

760
00:28:00,686 --> 00:28:02,833
Partnership funded missions to venus with a singular

761
00:28:02,833 --> 00:28:05,140
goal to find complex molecules, signs of life

762
00:28:05,140 --> 00:28:07,620
or life itself in the venus atmosphere. And

763
00:28:07,620 --> 00:28:09,604
this is building on a crazy idea from

764
00:28:09,604 --> 00:28:11,668
half a century ago, Carl Saga that if

765
00:28:11,668 --> 00:28:13,255
the surface of venus is too hot for

766
00:28:13,255 --> 00:28:14,366
life, which we all think it is.

767
00:28:15,177 --> 00:28:17,328
That high up in the atmosphere 50 kilometers

768
00:28:17,328 --> 00:28:19,480
above the surface as it gets colder. It's

769
00:28:19,480 --> 00:28:21,870
the right temperature for life. The problem is

770
00:28:21,870 --> 00:28:24,181
that venus unlike earth doesn't have water clouds.

771
00:28:24,673 --> 00:28:27,141
It has clouds made of acid, sulfur acid,

772
00:28:27,380 --> 00:28:29,449
which is orders of magnitude more acidic than

773
00:28:29,449 --> 00:28:31,359
the most acidic environments on earth where life

774
00:28:31,359 --> 00:28:31,678
is found.

775
00:28:32,553 --> 00:28:34,088
Yet lately, my team

776
00:28:34,558 --> 00:28:36,943
and a couple of others have been experimenting

777
00:28:36,943 --> 00:28:39,566
with sulfur acid and have demonstrated that some

778
00:28:39,566 --> 00:28:42,110
key biological molecules are stable in sulfur gas.

779
00:28:42,283 --> 00:28:45,294
Said amino acids, nucleic acid bases, fatty acids

780
00:28:45,294 --> 00:28:46,245
growing list of things,

781
00:28:46,879 --> 00:28:49,390
and we're building towards generating a synthetic, said

782
00:28:50,064 --> 00:28:52,443
informational polymer, not rd dna which is unstable,

783
00:28:52,601 --> 00:28:55,615
but swapping out parts to demonstrate that there

784
00:28:55,615 --> 00:28:57,534
could be some kind of primitive life, in

785
00:28:57,534 --> 00:28:58,913
the atmosphere to motivate

786
00:28:59,452 --> 00:29:00,830
people to get us

787
00:29:01,210 --> 00:29:01,849
back to Venus.

788
00:29:02,568 --> 00:29:04,666
So I would say my favorite missions

789
00:29:05,537 --> 00:29:08,185
or my favorite upcoming missions are small

790
00:29:08,639 --> 00:29:09,696
disruptive missions

791
00:29:10,230 --> 00:29:12,082
that complement these larger

792
00:29:13,434 --> 00:29:13,934
community

793
00:29:14,315 --> 00:29:15,454
based ones that

794
00:29:15,755 --> 00:29:16,394
Dave has mentioned.

795
00:29:17,434 --> 00:29:19,835
So guys, I I can't let you go

796
00:29:19,835 --> 00:29:20,734
without asking

797
00:29:21,368 --> 00:29:22,805
What is your favorite

798
00:29:23,364 --> 00:29:24,481
Exoplanet and why?

799
00:29:25,439 --> 00:29:27,753
Before I tell you the name of my

800
00:29:27,753 --> 00:29:28,232
favorite

801
00:29:28,711 --> 00:29:29,030
Exoplanet,

802
00:29:29,603 --> 00:29:31,299
I have to prepare you

803
00:29:31,675 --> 00:29:33,587
because, of course, in science fiction, I'm a

804
00:29:33,587 --> 00:29:35,261
big science fiction fan.

805
00:29:35,978 --> 00:29:40,146
Planets have... Have really wonderful dramatic names. You

806
00:29:40,146 --> 00:29:41,584
can think of H.

807
00:29:42,543 --> 00:29:44,721
Okay, from Star Wars or Ara

808
00:29:45,275 --> 00:29:46,394
from from June.

809
00:29:47,914 --> 00:29:49,134
Unfortunately, in

810
00:29:49,515 --> 00:29:50,394
in the real world,

811
00:29:51,275 --> 00:29:52,015
the planets

812
00:29:52,968 --> 00:29:56,147
get named after their stars by pending a

813
00:29:56,147 --> 00:29:57,442
lowercase b

814
00:29:57,816 --> 00:29:59,644
to the name of the star. And the

815
00:29:59,644 --> 00:30:00,144
stars

816
00:30:00,518 --> 00:30:01,733
themselves only have

817
00:30:02,123 --> 00:30:03,398
catalog numbers.

818
00:30:04,593 --> 00:30:07,461
Okay? So so so it could be that

819
00:30:07,461 --> 00:30:08,200
the first

820
00:30:08,657 --> 00:30:10,808
planet that we find that has signs of

821
00:30:10,808 --> 00:30:11,366
life on it.

822
00:30:12,497 --> 00:30:14,890
Has has an absolutely dreadful name, and I

823
00:30:14,890 --> 00:30:17,123
just wanna prepare the community for that. Alright.

824
00:30:17,362 --> 00:30:19,697
So then that being said, my

825
00:30:20,234 --> 00:30:21,611
my favorite planet

826
00:30:21,923 --> 00:30:23,697
is called L nhs

827
00:30:24,550 --> 00:30:25,448
11:40

828
00:30:25,744 --> 00:30:26,063
b.

829
00:30:27,178 --> 00:30:28,292
Why is it my favorite planet?

830
00:30:29,009 --> 00:30:29,247
Well,

831
00:30:30,058 --> 00:30:31,985
it's because it is

832
00:30:32,832 --> 00:30:35,845
Rocky planet, a terrestrial world. We know it's

833
00:30:35,845 --> 00:30:38,482
mass and it's it's its size,

834
00:30:39,120 --> 00:30:41,434
and therefore it's density very well. And we

835
00:30:41,434 --> 00:30:43,051
really think it looks like

836
00:30:43,827 --> 00:30:46,073
basically a scaled up version of the earth

837
00:30:46,073 --> 00:30:48,539
in terms of its bulk composition, the amount

838
00:30:48,539 --> 00:30:49,198
of iron

839
00:30:49,653 --> 00:30:52,015
and the amount of of Rocky mantle

840
00:30:53,171 --> 00:30:55,804
and it orbits a very nearby star, so

841
00:30:55,804 --> 00:30:57,261
it's somewhat accessible

842
00:30:57,719 --> 00:31:00,127
and the planet as at just the right

843
00:31:00,127 --> 00:31:02,283
temperature, it's a little bit cooler actually than

844
00:31:02,283 --> 00:31:02,682
the Earth,

845
00:31:03,400 --> 00:31:05,795
and and the combination of the high surface

846
00:31:05,795 --> 00:31:08,030
gravity of the planet and the fact that

847
00:31:08,030 --> 00:31:09,263
it's relatively

848
00:31:09,721 --> 00:31:12,696
cool means that it might have retained its

849
00:31:12,834 --> 00:31:14,053
atmosphere, and

850
00:31:14,510 --> 00:31:16,346
and it's an old star as well. So

851
00:31:16,346 --> 00:31:17,200
it could be that

852
00:31:17,717 --> 00:31:20,343
life has had time to to take root,

853
00:31:20,979 --> 00:31:23,287
and we could study study that life through

854
00:31:23,287 --> 00:31:26,247
the planetary atmosphere. But the other connection is

855
00:31:26,247 --> 00:31:28,557
that it was discovered by me and my

856
00:31:28,557 --> 00:31:30,548
team, and we did that with a,

857
00:31:31,424 --> 00:31:33,336
a special observatory called the Mu.

858
00:31:34,069 --> 00:31:36,465
Array, which was an array of robotic ground

859
00:31:36,465 --> 00:31:39,341
based telescopes, 8 of them in Arizona, 8

860
00:31:39,341 --> 00:31:40,220
of them in Chile,

861
00:31:41,434 --> 00:31:43,195
when we first set out to study this

862
00:31:43,195 --> 00:31:45,195
this population of planets around these very low

863
00:31:45,195 --> 00:31:47,434
mass stars. And so it's... I think I

864
00:31:47,434 --> 00:31:49,606
think it's a really citing scientific opportunity, but

865
00:31:49,606 --> 00:31:52,341
it's also just very near and dear to

866
00:31:52,719 --> 00:31:54,635
to me and my team personally.

867
00:31:55,513 --> 00:31:56,630
So that's my favorite world.

868
00:31:58,480 --> 00:32:00,792
That's, David. Although, III should've have thought this

869
00:32:00,792 --> 00:32:02,467
out, and I should have I should've have

870
00:32:02,467 --> 00:32:05,019
asked, what what's the... What's your favorite exoplanet

871
00:32:05,019 --> 00:32:07,990
that you haven't discovered? But we'll we'll leave

872
00:32:07,990 --> 00:32:09,289
that to a different podcast.

873
00:32:09,990 --> 00:32:11,830
And how about you, Sarah? Well, I was

874
00:32:11,830 --> 00:32:13,590
gonna guess 11 and 40 be for you.

875
00:32:13,830 --> 00:32:14,470
So... Yay.

876
00:32:15,761 --> 00:32:17,906
And usually, I answer this question, my favorite

877
00:32:18,065 --> 00:32:19,574
Xl Planet is the next 1. It's 1

878
00:32:19,574 --> 00:32:21,719
in the future because we've been so astonished

879
00:32:21,719 --> 00:32:23,546
before, surely there are still a lot more

880
00:32:23,546 --> 00:32:24,181
surprises left.

881
00:32:25,468 --> 00:32:27,299
Well, that's great. That's a great place to

882
00:32:27,299 --> 00:32:30,165
end, and Sarah and David, thanks so much

883
00:32:30,165 --> 00:32:32,155
for taking the time to come on the

884
00:32:32,155 --> 00:32:33,325
podcast and

885
00:32:34,400 --> 00:32:35,356
congratulations on

886
00:32:35,834 --> 00:32:39,020
winning the C plot prize in astro. She

887
00:32:39,020 --> 00:32:40,056
must be very pleased.

888
00:32:41,105 --> 00:32:42,217
To be this year's winners.

889
00:32:42,932 --> 00:32:43,330
Thank you.

890
00:32:44,045 --> 00:32:45,316
Thanks a lot. This has been a lot

891
00:32:45,316 --> 00:32:45,634
of fun.

892
00:32:52,958 --> 00:32:54,705
I'm afraid that's all the time we have

893
00:32:54,705 --> 00:32:57,406
for this week's podcast, which is sponsored by

894
00:32:57,406 --> 00:32:58,439
the cavalry prize.

895
00:32:59,249 --> 00:33:02,765
Thanks to David Char and Sarah Sig for

896
00:33:02,765 --> 00:33:05,721
joining me today. And a special thanks to

897
00:33:05,721 --> 00:33:06,360
our producer,

898
00:33:06,854 --> 00:33:07,730
Fred Isles.

899
00:33:08,448 --> 00:33:09,963
We'll be back again next week.

900
00:33:19,068 --> 00:33:21,860
The cavalry prize is a partnership involving the

901
00:33:22,259 --> 00:33:24,652
Norwegian academy of science and letters.

902
00:33:25,464 --> 00:33:26,361
The Norwegian

903
00:33:26,734 --> 00:33:30,150
ministry of education and research and the C

904
00:33:30,785 --> 00:33:30,944
Foundation.

905
00:33:31,976 --> 00:33:34,676
Since the first awards in 2008,

906
00:33:34,915 --> 00:33:38,764
the c prizes have honored 65 scientists

907
00:33:39,217 --> 00:33:40,725
from 13 countries.

908
00:33:41,519 --> 00:33:43,131
Find out more at

909
00:33:43,504 --> 00:33:44,004
Prize

910
00:33:44,393 --> 00:33:45,029
dot org.

911
00:33:54,665 --> 00:33:57,373
There will be no weekly podcast on the

912
00:33:57,373 --> 00:33:58,249
fourth of July.

913
00:33:59,124 --> 00:34:01,433
Instead, you can tune in on the second

914
00:34:01,433 --> 00:34:04,947
of July for the first installment of Physics

915
00:34:04,947 --> 00:34:05,821
world live,

916
00:34:06,537 --> 00:34:09,024
which will focus on quantum sensors.

917
00:34:10,287 --> 00:34:13,310
Featuring a panel of experts, this live event

918
00:34:13,310 --> 00:34:15,481
will explore the extraordinary

919
00:34:16,015 --> 00:34:18,120
capabilities of quantum sensors

920
00:34:18,574 --> 00:34:20,981
and look at how they could benefit humanity

921
00:34:21,196 --> 00:34:23,739
and shape our understanding of the world.

922
00:34:24,550 --> 00:34:26,630
You can find out more on the Physics

923
00:34:26,789 --> 00:34:27,670
World website.

924
00:34:28,309 --> 00:34:31,930
Just click on the Physics world live tab

925
00:34:32,230 --> 00:34:34,163
near the top of the homepage.