Pratique du Shadowing: The Most Likely Place to Find Aliens - Apprendre l'anglais à l'oral avec la vidéo
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Since I was a little kid, I've had a big question.
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Where are all the aliens?
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And still, as an adult, I desperately want to be alive when we actually discover extraterrestrial life.
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And I don't mean all of the conspiracy theories
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or the well -meaning but totally wrong science fiction or even the math that says, well, there should be someone somewhere.
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No. I want to know the real science.
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How are we actually going to discover aliens?
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Because if we want to be alive when that happens, cosmically, we don't have that much time.
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So I reached out to one of the most important scientists
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in the search for intelligent life outside our solar system
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and who is leading a new effort to find alien life inside our solar system too.
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In this episode, we're going to show you the real science
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and tech behind the incredible push happening right now to actually find aliens.
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Let's go.
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It's clear that step one to finding real aliens is finding their home.
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So this is every exoplanet, meaning planets outside our solar system, that we have ever found.
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Amazing.
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Isn't this cool?
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It's just incredible just how many there are, like countless, you'd say.
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That is Professor Sarah Seeger.
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She is arguably the most important person in the hunt to find aliens today.
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She invented some of the key methods that we've already used to understand what's out there.
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And she's now working on brand new ones that she's going to show us.
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But what blows my mind about this map is that when I was born, it was blank.
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Back then, we weren't even sure that there were planets around other stars.
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And what else is really amazing is this is still nothing.
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So take us back to 1995 when the first exoplanet was discovered.
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It was incredibly controversial.
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It was a big deal.
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What did you think about that as a graduate student?
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We were just simply searching for solar system copies.
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That's like a Jupiter very far from the star.
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And no one could really believe it.
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But the reason it was controversial, the signal was incontrovertible.
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So the signal was definitely real.
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But whether that signal was from a planet or a different phenomenon on the star itself, that was what was in question.
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And when you started your PhD and you decided to study exoplanets, you've said that people tried to dissuade you.
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They tried to say it was a waste of your time.
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Oh, totally.
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I mean, there were many people were born to be skeptics and scientists were trained to kind of build on that skepticism.
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Like you want proof.
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Many people would say, well, you should talk to my advisor.
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He'll tell you why.
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It's not a planet.
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So there's just this like constant pushback from most people.
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When we look at something like this, I want to explain to people how we got from nothing to this
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and then how we're going to get far beyond this, as you said.
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Okay.
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Here's our star.
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What are the different methods for filling in the map already?
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And then we'll get to the ones that we are going to use next.
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Well, the most popular method used today is called the transit method.
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And if this is our star, and this is a planet orbiting that star, for some systems, we're just lucky.
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The planet happens to orbit the star right along our line of sight, so the planet goes in front of the star,
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as seen from our telescope.
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You have to understand that it's all random, so some may be orbiting the star like this with respect to our viewpoint.
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But for the ones that go in front of the star,
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as seen from us, the starlight drops by a tiny amount every time the planet goes in front.
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Yeah.
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And then it goes back to normal brightness and then drops again.
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And the biggest drop could be one or two percent, for example.
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Fascinating.
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Yeah, the smallest drops are like many decimal places over.
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Or the star itself could be wobbling.
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Technically speaking, the planet and star are orbiting the common center of mass.
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So as the planet goes around, like when the planet's here, the star is wobbled a bit this way.
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And it just kind of keeps wobbling as the planet's orbiting
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because it's kind of moving its own orbit around its common center of mass.
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And we detect in the point of light.
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We detect the line of sight motion moving towards you, moving away from you.
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I mean, it's crazy, right?
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So that's the Doppler method.
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Yes.
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And you know, with the Doppler method, astronomers can measure velocities down to like 10 tens of centimeters a second.
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Think about that for a moment.
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Incredibly precise.
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Okay, so we've got transit, we've got Doppler.
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What's direct imaging?
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Direct imaging is where we can see the planet directly.
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So if this were here, and it were big enough and bright enough compared to its star, we could see light directly from this planet.
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Yes.
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And that is really hard to do because stars are incredibly bright.
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In fact, the definition of a star is that it has fusion and is creating its own energy.
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Planets don't do that.
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They never create energy.
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Energy just passes through them or reflects off of them.
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So they're going to be much, much fainter.
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And so this would be reflected light?
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In the best case of direct imaging.
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It could be.
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It could be reflected light.
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It could be absorbed energy that's re -emitted as heat.
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Got it.
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Okay, so we've got transit, we've got Doppler, and we've got direct imaging.
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Am I missing anything else?
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Well, there are other methods, they're just not as popular right now.
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There's also motion on the plane of the sky itself, and that is called astrometry.
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It's measuring very precise positions of stars.
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And again, all stars are moving, like with respect to us, but they're kind of moving in a straight line.
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But if there's a planet around it, it kind of is doing like a loop -de -loop,
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because the planet is causing it to move in three dimensions, the wobbles in three dimensions.
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And then one more method that honestly never gets airtime, because it's very complicated to describe, but it's incredibly powerful, and it is called gravitational microlensing.
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When we monitor stars, bright stars, very far away, and in between us and that far away star,
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an unseen star on planet just happened to drift by perfectly between us and that background star.
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And from Einstein, we know mass -bend space.
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Light rays that would normally go off into outer directions, they get bent around to us.
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And it acts like a lens, hence the word microlens, and magnifies the background star.
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Sometimes to several times.
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So enough that we could see some kind of difference or spot that we couldn't see before.
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All of these methods together are how we've been able, in my lifetime, to fill in over 6 ,000 exoplanets.
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But, um, what is that?
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See this weird cone -like shape?
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Yeah, what is...
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It's not just so bizarre.
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Like, let me ask you, do you think there are more planets in that direction?
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Or is it just that's the direction we have sampled?
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I have to say, no. I have to say, that has to be the direction that we have just pointed at the telescope.
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Yeah, it wouldn't make any sense if only planets formed along there.
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This must be the direction where the Kepler Space Telescope stared for three years.
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Three plus years, right?
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I mean, that is insane.
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So NASA launched the Kepler Space Telescope in 2009.
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And if you look inside it, you can see exactly this grid shape.
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It used the transit method to find all of these planets.
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But that means that if we pointed Kepler or another telescope like it in a different direction,
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it would find another cone -shaped chunk of these exoplanets.
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Just think about what's out there.
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This is just a small, tiny, tiny sample and it's everywhere.
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Yeah.
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Okay, so that's Kepler.
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What's that one?
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Oh my gosh, this is so cool.
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This has to be microlensing.
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Awesome.
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Because microlensing requires really, really bright stars in the bulge really far away to be the source star.
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Awesome.
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So in just the last few decades, we've gone from not knowing if there were planets around other stars to knowing that they are everywhere.
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But now, once we know a planet is there, the next step is to figure out what it's like.
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What's its atmosphere like?
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Who theoretically could be living there depending on what signatures are in that atmosphere?
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Because at the end of the day, what we want to know is, is anyone out there?
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You developed a way to do that.
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And it was totally groundbreaking at the time.
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And then you were proven right.
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And now it's being used in so many different ways.
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Could you explain to me how transit transmission spectroscopy helps us see in the atmospheres of exoplanets?
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Well, when the planet goes in front of the star, some of the starlight shines through the atmosphere if the planet has an atmosphere.
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But not all of the light makes it through.
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Like, imagine shining a flashlight through a fog.
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Some light makes it through, some doesn't.
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So we can take a spectrum of the star by itself and then take a spectrum during transit.
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And the difference in those two essentially tells us what's in the planet atmosphere,
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because the planet atmosphere is blocking some of the starlight at very specific wavelengths.
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You wrote a paper that explained how to do this with one of the early exoplanets that we discovered.
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One of the early stars.
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The first one.
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The first one.
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So this is HD 209458B.
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And then they actually did it and you were proven right.
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Correct.
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I was taken aside and told that they couldn't include me on the team because I was too young.
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You're like, but here's the method of exactly what you should do.
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And then when they went out and tried it, It worked.
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You have to understand just how early the days were.
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It wasn't like we could now race out and observe a whole bunch of other planets.
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There literally weren't any.
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There were maybe two or three transient planets, maybe two.
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And instead, I just got this giant pushback because at the time I was applying to become a professor.
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And people would just be, well, it's interesting, but it's a one object, one method success.
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Meaning that it's cute, but...
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we're never going to have enough transiting planets. But
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because I had been working in this race to find transiting planets by just looking at tons of stars at one time,
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I actually knew how close we were.
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It's very, very satisfying when nature behaves how you think it should behave.
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Yeah.
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You know, if you want to think about it, think about like a ball of gas at chemical equilibrium with the radiation hitting it.
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And you could then be, well, what are the elements that are there?
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And then you can kind of go down that list of elements and say, which one is a strong absorber?
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And so it's just very, I just feel happy that nature agrees.
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This is crazy to me because I have always heard
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that our atmosphere is like the skin of an apple on an apple.
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Like it's just incredible.
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We think of it as so thick, it's incredibly thin.
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But you're telling me that we can look at a star that's a tiny point of light.
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We can see when something changes in that point of light
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and we can see the light passing through basically the skin part of the apple on its way to us.
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Yes, we can.
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However, not for all kinds of planets.
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Right now, it doesn't work for an Earth -Sun twin.
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Because our Sun, that backdrop star, is so big and so bright.
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And our Earth's atmosphere is so tiny.
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Do none of the methods work for Earth -like planets?
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Not yet.
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So that whole map that we just looked at, none of those are really like Earth?
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None of them are Earth twins.
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So any headline that we've ever seen about Earth -like planets being discovered has been using a really,
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really broad, not super scientific definition of what that means.
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Those ones are either the right size, but they're around much smaller stars, which changes what could be alive there.
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Or actually way, way bigger than Earth.
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We can't find an Earth twin yet.
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We're trying.
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And we're trying because we think maybe that's the best shot at finding life, or at least life that we can recognize.
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For finding Earth twins, why is it so hard?
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It's so hard because planets are so small, so low mass, and so dim compared to the adjacent host star.
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Our Earth is hundreds of thousands of times less massive than our sun.
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But our Earth is 10 billion b, billion times fainter than our sun in reflected light.
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So I don't know if you've come across anything where you have to go to 10
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or more decimal places to get the job done.
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Never in my life.
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It's tough.
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There's no way to sugarcoat how hard it is to find an Earth twin.
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So what could we do about that?
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What we want to do, and this idea has been around for decades, is to go to space above the blurring effects of Earth's atmosphere
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and to be able to block out the starlight so we can see the planet light directly.
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Like putting my thumb against the sun?
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Sure, it could be like putting your thumb against the sun.
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How do we do that?
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So it turns out, crazily enough, but in the 1920s, a French optical physicist named Leo,
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he actually invented a device called the coronagraph about our sun.
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Have you ever seen a total solar eclipse?
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Yeah.
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When you block out the bright part of the sun, you can see the fainter but hot plasma in the corona.
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So he invented something called a coronagraph where anytime you want, you can block out the sunlight and see the corona.
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People had that idea.
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Well, why don't we use this device inside the telescope?
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We can block out starlight and separate out the planet light.
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It's tricky.
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Let's imagine you brought me some banana bread and I say, thank you so much, Cleo.
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I forgot to mention, I don't eat cinnamon.
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Meanwhile, you put cinnamon in and there's a lot of flour.
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There's say 10 billion parts flour and one part cinnamon.
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And can you please take that cinnamon out?
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Yes, absolutely.
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No, no, I think the answer is no. So that's tough.
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Give me a hundred thousand years.
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What if I said, I knew you're coming to visit me
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and that you had been trying to make this banana bread a hundred times better.
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I'd say I know you're trying to make this great banana bread please bring the cinnamon in a separate dish
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so if the others want they can put it on top I don't eat cinnamon
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so now remember the cinnamon is representing the planet light
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and the banana bread
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and all the flour is representing the star light there's way more flour than cinnamon now they're separate
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they never get mixed
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and it's very easy to keep them separated so we need a technology
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that separates the planet light so that a telescope can analyze either just
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that light or just the stars light but not like to do
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that because the problem is when they're mixed up it's just hard to separate them again
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and inside the telescope the light bounces around
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and you have to make the telescope very stable
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so I love the way where we always keep them separated
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how do we do it we do it with something called star shade awesome can I go grab
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that again you can be careful be careful the edges are very sharp
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I've wanted to play with this ever since I got in this office Starshade is a giant, specially shaped screen.
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This is a 1 % scale model.
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So this is huge.
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Well, imagine if it's 100 times bigger.
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Awesome.
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Starshade would have its own spacecraft, and it would formation fly with a space telescope.
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So they'll both be operating in space, far away from Earth's gravity, because they have to line up extremely precisely.
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And Starshade would be blocking out a known star to search for planets around that star.
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The starlight will be blocked and only the planet light will enter the telescope.
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And why is it shaped like this?
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Well, that's a great question.
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You know, if you were to put a circular screen or a square screen in space and block out a star, you would have rings, ripples.
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Because light can act like a wave.
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Yeah.
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And it actually bends around the edges of a giant circular screen.
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And it will create ripples, just like dropping a pebble in a pond.
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And those ripples are light ripples, and the light ripples are way brighter than any planet you're looking for.
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Spitzer invented this special shape in the 1960s.
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and what he realized was
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that this shape what it enables is the starlight still acts like a wave
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and bends around but it interacts with itself
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so cleo do you see this black thing behind me do you want to guess what it is i think
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that should be a full size version of just this little piece
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it is it is just a single petal just that correct cool
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and it's it gives you a sense of just how giant
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this this screen could be what's the status of it right now like would starshade be something
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that could see starshade you know it was invented in the 1960s
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and every decade it has been revived and shelved
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and we had a real heyday since about 2013
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when starshade has been moving forward very rapidly we had directed funding
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we solved a lot of hard problems we have large radio deployables in space
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that we have heritage for to build how starshade will still and deploy but unfortunately right now, the Starshade funding is on hold.
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And so we're trying to keep Starshade alive.
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Right now, NASA has plans to build the Habitable Worlds Observatory using the coronagraph on the inside.
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And that's the one where it's possible, but it's hard to separate out the cinnamon.
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Very hard to separate the cinnamon.
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And the coronagraph still has a ways to go for lab demo.
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Starshade has been demonstrated to work to the contrast needed.
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And big picture to remind people of why,
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if this show is all about participating in those features and caring about them to try and make them happen,
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the reason to care about starshade is if we can separate out the star's light, we have a chance at detecting more
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Earth -like planets.
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So let's assume that some of these methods happen and we are looking at Earth -like planets around sun -like stars.
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What are we looking for?
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That's a great question.
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And to be frankly as honest as possible, we are still working on that.
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Awesome.
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What are the options?
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Well, one option is the Earth twin.
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Literally carbon dioxide and...
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Yeah, tiny bit of carbon dioxide, a lot of water vapor on Earth.
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Oxygen is made by plants and photosynthetic bacteria.
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It's highly reactive.
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It wouldn't be in our atmosphere unless it's continually produced.
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That's life as we know it on Earth.
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But alien planets could work completely differently.
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So we're also trying to get better at understanding what life could be like that's really different from us.
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Life as we don't know it.
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Let's imagine for a moment there's a Clio and there's a Professor Seeger on an alien world and they don't have oxygen.
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And they're talking about the same conversation and they're saying, what kind of planet do you think could support life?
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They might even say, well, we found this planet has a lot of oxygen.
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It's terrible.
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It has so much oxygen.
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How could anyone live there?
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It would have large regional fires at any time.
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We'll find a bunch of things.
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We'll be like, wow, this has oxygen, or this has this gas, or this has another gas.
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But we won't be sure because there will always be the opposing view.
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A lot of people have their favorites.
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One of my favorite gases is phosphine.
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It has a unique spectral signature
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that doesn't overlap with any other major gases like carbon dioxide
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or methane or anything on earth it shouldn't exist because it takes energy to make it.
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Yet on earth it does exist, but it's only associated with life.
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Okay, so those could be signs of microbes.
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But what about intelligent life?
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When we search for intelligent life, are we searching for different things?
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Are we searching for the same biosignatures?
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And when we say intelligent, what do we actually mean?
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Like Oh my God, intelligent life.
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This is incredible.
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Yeah.
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Like imagine if you found a dog on an alien planet.
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This is my dog, Thor.
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He's a 10 pound mini Australian Shepherd.
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He's a big fan of Hill's Pet Nutrition and he's 12 years old, but I think he still looks like a puppy.
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Thor has been my guy since long before I started huge.
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Oh, and he's been with me every step of making this show.
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But this show also means that I need to leave him sometimes.
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The longest was a trip to Antarctica for three weeks.
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I feel so guilty when I'm gone.
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Like, he's 12 years old.
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I want every moment with him.
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And I want to try to give him the best of everything that I possibly can.
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The big one is his food.
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Thor really likes this one from Hills, which is why I'm so excited to partner with them.
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What he likes is the taste.
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What I like is the science.
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Because Thor's gut is home to trillions of microbes that help digest his food and support his immune system.
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And prebiotic fiber is food for the good ones.
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So Hills uses two kinds that work in different parts of his gut.
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So when those bacteria break the fiber down, they make helpful compounds that support his organs like his heart and his kidneys.
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And every time Thor turns food into energy, he makes free radicals, which are these unstable molecules that can damage his cells.
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Antioxidants are the cleanup crew.
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Vitamins C and E help neutralize those free radicals before they do harm.
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The older Thor gets, the more free radicals his body makes, so the antioxidants in his food matter more.
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No food is magic.
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But giving his body the right building blocks backed by real research, that's something I can do.
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I want the science to help him live longer so that I can have more time to love him.
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Discover the science behind a long, healthy life for your pet at hillspet .com slash science does more.
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Okay, back to intelligent aliens.
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Are we talking about any kind of sentience?
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Are we talking about little green men?
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Like, how does the field think about the range from microbial life to intelligent extraterrestrial civilizations?
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When it comes to gases, of course, we humans give off gas.
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We're breathing out carbon dioxide.
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We have cows giving off methane.
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There are gases that intelligent life does produce, but we can't separate out with basic gases, whether it's microbes or intelligent life.
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And when it does come to gases, though, there is a category called technosignature gases.
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We produce some complicated gases, like we produce chlorofluorocarbons.
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And there are some gases, it's going to sound a bit obscure, Sf6, sulfur tetrafluoride, and NF3.
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We have some gases that are only used industrially that life never makes.
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And then people love techno signatures in general, like purposeful radio communications or crazy large structures aliens may have built.
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So there's sort of the full range out there of what people think about.
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But it's hard, really hard.
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Like from afar, aliens with telescopes more sophisticated than ours,
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like just more like what we're trying to build like starshade they would see oxygen they might infer those oceans
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and continents would they see city lights
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or pollution no would they see the great wall of china no
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so it's like a whole other level to find techno signatures yeah
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so we're not going to see dogs
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we're not going to see humanoids unfortunately right now that's way beyond what we can do.
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I have a question from someone who I have previously interviewed on this show, Project Hail Mary author Andy Weir.
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He wrote a story about one of my favorite aliens of all time.
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His name is Rocky.
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Hi, Grace.
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He asks, Earth converted sunlight into fossil fuels for millions of years.
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Would that energy discrepancy be detectable comparing a planet's energy radiation to its presumed energy absorption of the star?
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Or would it be lost in the noise of normal variants?
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I think he's asking, could some alien civilization very far away see
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that we are giving off more energy than we should be currently absorbing from the sun, therefore we are here?
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Well, that's a good question.
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Right now, we can't detect that.
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You have to think about it.
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We can, it sounds like grand and incredible, all the things we can do.
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But if you wanted to really analyze that, like under a microscope, so to speak, we can barely do anything.
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So, you know, how our planet's heating up and we have forest fires and we have climate change, we couldn't detect that from afar.
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Like, there's no way they could, if they're lucky, they could see we have carbon dioxide at all,
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let alone that it's going up parts per million every year.
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Thinking about that map and thinking about now we're in a world where we've filled it even more in,
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where do you think we're most likely to find intelligent alien life?
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First we ask, Are there exoplanets?
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Check.
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Are there rocky exoplanets in the habitable zone where they might host life?
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Check.
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Now we're on to, is there going to be water vapor or liquids where life could exist?
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We're still working on that.
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It sounds like you're outlining popularly the Drake equation.
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Those are the variables in what I understand to be the Drake equation, but I also know you have the Seeger equation.
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Yes, yes.
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And I, by the way, what are the differences?
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Drake's equation is broken down into terms.
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The search for extraterrestrial intelligence by way of radio communication.
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How many stars are being born each year?
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What fraction of them have planets in the habitable zone?
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What fraction have intelligent life?
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How long do civilizations last?
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And I took the Drake equation and recast it for the search for not intelligent life, but any life by way of biosignature gases.
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And I did this considering a few different cases, but one case was what we talked about,
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transmission spectra and I said if you have a certain number of stars here are the factors that are important.
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We have to get really lucky in the time boxed period of when they're alive.
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Yeah but one concept I do love I've really glommed on to it's a really scary concept.
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Okay.
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Do you want to hear it?
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Yes I'm ready.
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Well AI is starting to pervade our life.
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Yes.
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And we only have a glimpse of where it's heading.
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Yes.
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And there's a big fear rightly so that a few generations from now
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or sooner or sooner right it could be 10 years could be a generation or two
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AI is our boss and it kind of has taken over.
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We also in parallel have data farms being considered for space.
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Have you heard of those?
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Yeah.
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This would ruin our night sky.
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So it's very depressing for astronomy.
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But imagine for a moment that you have AI in space.
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So they're getting solar energy and they're giving off heat to space, but they also have the ability to reproduce
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because on earth are a lot of big startups with big money about robotic self -driven AI.
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Have you heard of that self -driven labs rather
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so now let's put all
445
that together the ice taking over it's in space
446
it can self -reproduce it's getting energy from the sun it has intelligence it wants more energy
447
where's it going to go the sun okay it'll orbit our sun maybe
448
that's what we should be looking for yeah intelligent ai yeah maybe it's not just our sun
449
and i can't take claim for for this idea
450
and maybe now it's moving to a local black hole where there's more energy maybe
451
now it's moving to our galactic black hole.
452
I mean, there's a lot of ideas out there, but if you want to think about how long we've been here,
453
really just the blink of an eye and the sort of exponential we're on for AI, you know, maybe that's what we should be looking for.
454
What are your, I want to know what your thoughts are.
455
I just outlined a scenario.
456
I didn't say whether I totally buy into it, but what are your thoughts?
457
I am less scared of that than I thought I was going to be.
458
I would not assume in either direction about the way that AI is either constrained here on earth or treats us.
459
So within that hypothetical, there are still a lot of options where humanity is happy or supported by the AI.
460
And yes, the AI is self -replicating and going toward the black holes and maybe on behalf of humanity, looking for other contact with other AIs.
461
I absolutely buy that we've only been around for a short period of time.
462
We're trying to find civilizations that are either just below us
463
or way above us because we assume
464
that we've only started being able to detect or being able to emit ways that they could detect fairly recently.
465
So we need to find somebody older than us, basically.
466
Right, right.
467
And if that's the case, then it seems to me plausible that the first thing
468
that we would encounter are their forms of technology that they have created somehow.
469
Maybe.
470
I buy that.
471
What are your thoughts on it?
472
Well, I think we should definitely add it to the list of something we're looking for.
473
Yeah.
474
Because that could be a sign of intelligent life.
475
And you know, do you know what I'm saying?
476
Like they might not send us a radio signal.
477
Maybe they don't want to or can't.
478
But I easily see it as not too far of a leap from where we're heading.
479
We've only been talking about exoplanets so far.
480
Right, right.
481
It seems to me that it's still possible to find microbial life somewhere in our solar system.
482
Why not?
483
You're working on a way to do this.
484
I definitely am.
485
But not on the planet that most people think.
486
People know about Mars.
487
Venus sometimes gets called Earth's evil twin.
488
How did it get that nickname?
489
Well, Venus itself is about Earth's size and about Earth's mass.
490
And many people think it was born like
491
Earth with water oceans, maybe it had continents and like a nice atmosphere.
492
But Venus is just that much closer to the sun.
493
And it had volcanoes and it's hotter and it had a greenhouse atmosphere and eventually it just got too hot.
494
Venus went through a tipping point and got too hot for water to be sustainable.
495
So then that carbon dioxide that supposedly was dissolved in the ocean came back to the atmosphere and made it even hotter.
496
And eventually it's just way too hot on the surface anyway for any kind of life we could imagine.
497
In the 70s and early 80s, over a dozen former
498
Soviet Union missions went to Venus.
499
NASA sent Pioneer Venus.
500
So where could there possibly be life on Venus?
501
Well, not on the surface, which is too hot.
502
But just like on Earth, when you go in the airplane or you hike up a mountain, it gets colder and colder.
503
And that also happens on Venus, on most planets actually.
504
On Venus, about 50, 50 kilometers above the surface, it's the right temperature for life.
505
So there could be life in the clouds of the Earth.
506
There could be life in the clouds.
507
And this by no means was my idea.
508
Carl Sagan, we think, was the first one to propose this.
509
I remember.
510
It is just possible that the hot region exists at a high altitude in the ionosphere of Venus.
511
The surface temperature could then be almost
512
Earth -like, and life as we know it could exist there.
513
So how are we going to find out?
514
I know about missions to Mars.
515
You're leading a mission called the Morningstar mission.
516
Yes, I can tell you about that.
517
So we want to go to Venus.
518
It's still too crazy.
519
It's too taboo for NASA and large government agencies.
520
So we're trying to do a series of missions.
521
Each builds on the one before that are largely privately funded.
522
And we call ourselves the Morningstar missions to Venus.
523
We're also trying to get this message across of like a new dawn is rising for space missions.
524
Instead of waiting over four decades to go back to the atmosphere of Venus or a planet, let's shift gears.
525
Let's complement the NASA missions and have small, very, very focused missions that just have like a single goal.
526
So the goal would be of the Morningstar missions?
527
Well, the eventual goal, eventually, in time, is a sample return.
528
Awesome.
529
is that the pieces that we should talk about yes why don't we talk about
530
that yeah let's bring that over okay this is all right thank you
531
so this is a 3d printed model of the actual size
532
of morning star's first mission to venus called the rocket lab mission to venus it's beautiful
533
and this first mission is like a small cheap mission
534
so this is the entry capsule but it's also the probe shell
535
so normally the entry capsule like opens up but this is just going to be it it's just this
536
it'll just get dropped off it'll slow down based on its own drag
537
and it will have five minutes in the clouds to perform its job
538
and it'll keep going and slow down
539
and eventually it will crash land on the surface will it send back enough data for us to understand well
540
it has to
541
so it's kind of like all like a puzzle
542
you have to make sure it's all tied together properly would you like to open it yeah i didn't know
543
that was an option yeah it's right here just put your hand like in the and see what's inside.
544
And this is a 3D printed model.
545
Cool!
546
You have the best choice.
547
Would you like to take it out?
548
Yes.
549
And this, you know, kind of looks like a little alien.
550
Doesn't it look kind of like an R2 -D2?
551
Yeah, look.
552
Yep.
553
It's not.
554
Isn't it cute?
555
Inside would be like the computer, the radio, the batteries.
556
You know, inside would be like the mission itself.
557
So what we're going to do is we have a laser that we're going to be shining through this window.
558
And not shown on here, but one of these will have a hole one of these side things will have a hole.
559
So the laser will shine out and it will hit the cloud particles.
560
And so from the information that it sends back, we'll find out more about what's hidden in those clouds.
561
This is part one of the Morningstar missions.
562
Part one.
563
I think in latter parts, you're going to use this.
564
What is this?
565
Okay, I want you to know that when you build things for space, there's like 100 steps.
566
Yeah.
567
So this would be about step, say, three out of 100.
568
Okay.
569
Maybe step five.
570
Okay.
571
Well, what we'd like to do eventually is capture the cloud particles of Venus
572
and have like literally liquid to analyze in the atmosphere.
573
And so the first step in doing that, we call it our cloud catcher.
574
You know how when you're in a foggy environment and the fog collects on your jacket?
575
It's like that.
576
Only there are these wire mesh layers.
577
But there's still a big problem with these clouds.
578
The clouds aren't made of water.
579
That's the problem.
580
What are they made of?
581
Acid.
582
Concentrated sulfuric acid.
583
Can life survive in concentrated sulfuric acid our life cannot survive it just cannot there's no way it can
584
so one thing my lab does is we study molecules in concentrated sulfuric acid
585
and so while our life can never survive our dna is completely unstable it turns out
586
that some molecules are stable like our amino acids stable in
587
sulfuric acid huh our nucleic acid bases stable small peptides stable lipids stable we put a lot of molecules in sulfuric acid.
588
We study other non -water solvents, but it's actually pretty remarkable that you can just do this in the lab and find out amazing things.
589
We're trying to find a DNA -like molecule that's stable and concentrated sulfuric acid, and we have a big milestone in that direction already.
590
Can you tell us what the milestone is?
591
Sure.
592
We have found that a molecule like DNA, it's not DNA itself.
593
Oddly, it's called PNA, peptide nucleic acid.
594
It's different from DNA.
595
It has the same latter part, but a different backbone.
596
And we have demonstrated that up to about 50 degrees Celsius, it's stable in like pure concentrated sulfuric acid.
597
So this would tell me on the clouds of Venus, for example, that there could be built using similar building blocks,
598
building different things, not DNA, but other things.
599
That's right.
600
Life made out of those things there.
601
Right.
602
Cool.
603
As proven by it surviving in these jars.
604
One of the things that has always struck me about this is people are just
605
so interested in the topic of finding aliens.
606
You know, the Pentagon releases UAP information.
607
And I went to Antarctica recently,
608
and you would be surprised at the number of people who genuinely told me that they thought I'd find aliens there.
609
And it feels like this subject is either taken over by theories about unproven encounters
610
or well -meaning science fiction that represents a very different world than the one
611
that we're living in and sometimes gives misimpressions about how this might happen.
612
And then there's you and scientists like you that are trying to say, here are the actual ways in which we would realistically find aliens.
613
Here's the human work that needs to go into that.
614
If you're talking to millions of people, which I hope we are on this episode, what would you encourage them to direct their attention to?
615
There's so many things scientifically.
616
Two things that are my personal favorites.
617
One is the upcoming
618
Nancy Grace Roman Space Telescope launch.
619
Because out of all those planets out there, we still don't know how common or rare our solar system is.
620
It's very hard to find.
621
We know it's rare.
622
because we found all the other systems, but we don't know how common it is, and the new telescope should answer that.
623
And by that you mean the particular kind of arrangement of planets we have?
624
Yes.
625
Got it.
626
Yeah.
627
And the other thing that I've been really intrigued with lately too is, we're not kidding.
628
The ingredients for life are found everywhere.
629
So this isn't about aliens, but honestly, the more chance for aliens to be out there is
630
if there are more chances for life to be out there.
631
All the test data, all the Kepler data, all the data made by the James Webb Space Telescope, because it's all taxpayer funded,
632
all the data is public.
633
And it's not only public, but there are different levels of data product.
634
You could be brave and like take the almost raw data, or you could take the light curve that's already made and look for unusual things.
635
You can get your hands dirty as well as learning more domain knowledge along the way.
636
In preparation for this, I read your amazing book.
637
Thank you.
638
It's called The Smallest Lights in the Universe.
639
And if you don't mind, I'm going to ask you a personal question about it.
640
We can skip right over it if you're comfortable.
641
The title of this book, I think, refers to the fact that you're a scientist who is looking at these tiny little lights made by planets.
642
And they're the smallest.
643
They're so faint.
644
And also you talk about how your husband died when both of you were very young and you had young kids.
645
And you're looking for hope in small things.
646
You're dealing with grief.
647
Could you tell me about what your personal motivation was to continue this work
648
and how you think this has personally played out for you?
649
Well, I'm really pleased you understood the title because it does have the dual meaning of personal,
650
where when you're really down in the bottom of despair, you have to hold on to those small slights of hope.
651
And in the other sense, they are the small slights of Earth.
652
They're 10 billion times stancher than the suns.
653
But what happened was this, and I'm going to try to say it for you.
654
You know, the human mind is an amazing thing we don't understand why we have consciousness
655
we don't understand why we feel the way we do
656
but i'll tell you one thing
657
when my first husband mike died it was an incredible journey you can die well
658
and it's a really special journey it's very very important as a culture
659
that we can be open minded to that
660
and after he died he had the perfect death i just want you to know yeah
661
and i was by his side and everything and after that uh life was meaningless all of a sudden
662
because that's like if you have anything in your life that's
663
so momentous what's the point of living yeah
664
and i really held on to those smallest lights
665
and decided my life was going to have purpose and
666
that purpose comes on many axes one axis is it is my dream to find another earth
667
and that is that is my purpose
668
and after he died i had a wonderful few years of discovery but it's not just finding another earth, it's finding life out there.
669
It's finding ways to get job done.
670
And it's inspiring the next generation and giving everyone permission.
671
I don't want you to have a catastrophe to like get on your big thing.
672
But the point of the story is also that we can do great things.
673
And we do have resilience.
674
And there is a path forward if you can strategize
675
and get on that path and have help from your teachers
676
and friends and hopefully parents or like others to help you get there, we all have a way to get the job done.
677
Thank you for the job that you're doing.
678
I think a lot of people are like me who feel personally inspired by you
679
and know about the work that you're doing and feel that from PhD onward,
680
you have struck this very risk -taking path on behalf of all of us that has a lot of human benefits, right?
681
I think you personally are inspiring.
682
and also I think there are lots of people who maybe until now did not know about this work
683
and now can see how you've been benefiting them all along
684
so thank you so much for your time and for your work and thank you Cleo really it's been a pleasure
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Vocabulaire et conseils d’expression pour cette leçon
Cette leçon d’expression orale s’appuie sur la vidéo « The Most Likely Place to Find Aliens ». Cette vidéo contient 41 phrases et 7511 mots à répéter en shadowing. La partie parlée dure 38:51. Le locuteur parle vite, environ 193 mots par minute : attendez-vous à des liaisons et à des sons réduits. 84 % des mots font partie des 3 000 mots les plus courants en anglais ; le reste mérite d’être vu avant de commencer. 90 de ses 41 phrases sont des questions : un bon entraînement pour l’intonation interrogative et les réponses courtes.
Vocabulaire clé de cette vidéo
15 mots de la vidéo à retenir, avec leur prononciation et leur sens :
| Mot | Prononciation | Sens |
|---|---|---|
| atmosphere nom | /ˈætməsˌfɪɹ/ | atmosphère |
| intelligent adjectif | /ɪnˈtɛlɪd͡ʒənt/ | intelligent |
| telescope nom | /ˈtɛl.əˌskoʊp/ | lunette, télescope |
| cloud nom | /ˈklaʊ̯d/ | nuage |
| acid nom | /ˈæsɪd/ | acide |
| cinnamon nom | /ˈsɪnəmən/ | cannelier |
| stable nom | /ˈsteɪ.bəl/ | étable, écurie |
| transit nom | /ˈtɹæn.zɪt/ | transit |
| twin nom | /twɪn/ | jumeau, jumelle |
| orbit nom | /ˈɔɹ.bɪt/ | orbite |
| oxygen nom | /ˈɑksɪd͡ʒən/ | oxygène |
| detect verbe | /dɪˈtɛkt/ | déceler, détecter |
| dioxide nom | /daɪˈɑksaɪd/ | dioxyde |
| molecule nom | /ˈmɑ.lɪ.kjul/ | molécule |
| incredibly adverbe | /ɪŋˈkɹɛdɪbli/ | incroyablement |
Les verbes à particule que vous entendrez
| Mot | Prononciation | Sens |
|---|---|---|
| give off verbe | /ɡɪv ɒf/ | émettre |
| find out verbe | découvrir, savoir | |
| take over verbe | reprendre | |
| pass through verbe | traverser | |
| slow down verbe | ralentir, décélérer | |
| turn out verbe | se finir, se terminer | |
| come across verbe | avoir l'air de | |
| drop off verbe | s’endormir, tomber |
Des phrases à répéter
Des phrases courtes et complètes de la vidéo, à réutiliser dans la conversation de tous les jours :
- How are we actually going to discover aliens?
- Am I missing anything else?
- How do we do that?
- Have you ever seen a total solar eclipse?
- Why don't we talk about that?
La grammaire de cette vidéo
Les structures que le locuteur utilise le plus, avec les mots exacts de la vidéo :
| Structure | Dans la vidéo |
|---|---|
| Present perfect continu have/has been + -ing — une action commencée avant et toujours en cours | has been using · has been moving · We've only been talking |
| Present perfect have/has + participe passé — une action passée qui compte encore maintenant | I've had · have ever found · you've said |
| Voix passive be + participe passé — l’accent est mis sur ce qui arrive, pas sur qui le fait | was born · was discovered · were born |
| Propositions relatives who / which + proposition — une précision sur une personne ou une chose | Hills, which is · radicals, which are · someone who I |
Prononciation à surveiller
Le locuteur utilise 151 contractions et formes réduites, comme we're, don't, you're. Prononcez-les sous leur forme courte, telles que vous les entendez.
- Les sons « th »: thumb /ˈθʌm/, methane /ˈmiːθeɪn/, thin /ˈθɪn/, thick /θɪk/, breathe /bɹiːð/
- Les sons « sh » et « zh »: equation /ɪˈkweɪ.ʒən/, shine /ʃaɪn/, civilization /ˌsɪv.ɪ.laɪˈzeɪ.ʃən/, fiction /ˈfɪkʃən/, transmission /tɹænsˈmɪʃən/
- Mots longs — placez bien l’accent: intelligent /ɪnˈtɛlɪd͡ʒənt/, incredibly /ɪŋˈkɹɛdɪbli/, civilization /ˌsɪv.ɪ.laɪˈzeɪ.ʃən/, complicated /ˈkɑm.plɪˌkeɪ.tɪd/, humanity /hjuˈmænɪti/
Les sons difficiles pour les francophones :
- /h/ — il se souffle, il n’est pas muet: behalf /bɪˈhæf/, humanity /hjuˈmænɪti/, harm /hɑːm/, helpful /ˈhɛlp.fl̩/, hence /ˈhɛns/
- /tʃ/ et /dʒ/ — à ne pas adoucir en « ch » et « j »: intelligent /ɪnˈtɛlɪd͡ʒənt/, oxygen /ˈɑksɪd͡ʒən/, encourage /ɪnˈkʌɹ.ɪd͡ʒ/, heritage /ˈhɛɹ.ɪ.tɪd͡ʒ/, jacket /ˈd͡ʒæk.ɪt/
- /r/ anglais — langue recourbée, sans frotter la gorge: atmosphere /ˈætməsˌfɪɹ/, transit /ˈtɹæn.zɪt/, orbit /ˈɔɹ.bɪt/, incredibly /ɪŋˈkɹɛdɪbli/, concentrate /ˈkɑn.sən.tɹeɪt/
Comment s’entraîner avec cette vidéo
- Écoutez la vidéo en entier une fois sans parler et notez les mots que vous ne connaissez pas.
- Commencez à la vitesse 0,75×, répétez phrase par phrase, puis revenez à la vitesse normale quand cela devient facile.
- Enregistrez-vous et comparez avec l’original, en faisant attention à des mots comme atmosphere, intelligent, telescope.
Qu'est-ce que la technique du Shadowing ?
Le Shadowing est une technique d'apprentissage des langues fondée sur la science, développée à l'origine pour la formation des interprètes professionnels. Le principe est simple mais puissant : vous écoutez de l'anglais natif et le répétez immédiatement à voix haute — comme une ombre suivant le locuteur avec un décalage de 1 à 2 secondes. Les recherches montrent une amélioration significative de la précision de la prononciation, de l'intonation, du rythme, des liaisons, de la compréhension orale et de la fluidité.