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Jeremy Kasdin: The flower-shaped starshade that might help us detect Earth-like planets
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Astronomers believe that every star in the galaxy has a planet, one fifth of which might harbor life. Only we haven't seen any of them -- yet. Jeremy Kasdin and his team are looking to change that with the design and engineering of an extraordinary piece of equipment: a flower petal-shaped "starshade" positioned 50,000 km from a telescope to enable imaging of planets about distant stars. It is, he says, the "coolest possible science."
Jeremy Kasdin - Planet finder
Using innovative orbiting instruments, aerospace engineer Jeremy Kasdin hunts for the universe’s most elusive objects — potentially habitable worlds. Full bio
Using innovative orbiting instruments, aerospace engineer Jeremy Kasdin hunts for the universe’s most elusive objects — potentially habitable worlds. Full bio
Double-click the English transcript below to play the video.
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The universe is teeming with planets.
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I want us, in the next decade,
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to build a space telescope that'll be able to image
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an Earth about another star
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and figure out whether it can harbor life.
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My colleagues at the NASA
Jet Propulsion Laboratory
Jet Propulsion Laboratory
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at Princeton and I are working on technology
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that will be able to do just that in the coming years.
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Astronomers now believe that every star
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in the galaxy has a planet,
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and they speculate that up to one fifth of them
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have an Earth-like planet
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that might be able to harbor life,
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but we haven't seen any of them.
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We've only detected them indirectly.
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This is NASA's famous picture of the pale blue dot.
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It was taken by the Voyager spacecraft in 1990,
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when they turned it around as
it was exiting the solar system
it was exiting the solar system
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to take a picture of the Earth
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from six billion kilometers away.
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I want to take that
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of an Earth-like planet about another star.
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Why haven't we done that? Why is that hard?
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Well to see, let's imagine we take
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the Hubble Space Telescope
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and we turn it around and we move it out
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to the orbit of Mars.
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We'll see something like that,
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a slightly blurry picture of the Earth,
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because we're a fairly small telescope
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out at the orbit of Mars.
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Now let's move ten times further away.
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Here we are at the orbit of Uranus.
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It's gotten smaller, it's got less detail, less resolve.
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We can still see the little moon,
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but let's go ten times further away again.
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Here we are at the edge of the solar system,
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out at the Kuiper Belt.
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Now it's not resolved at all.
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It's that pale blue dot of Carl Sagan's.
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But let's move yet again ten times further away.
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Here we are out at the Oort Cloud,
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outside the solar system,
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and we're starting to see the sun
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move into the field of view
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and get into where the planet is.
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One more time, ten times further away.
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Now we're at Alpha Centauri,
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our nearest neighbor star,
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and the planet is gone.
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All we're seeing is the big beaming image of the star
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that's ten billion times brighter than the planet,
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which should be in that little red circle.
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That's what we want to see. That's why it's hard.
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The light from the star is diffracting.
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It's scattering inside the telescope,
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creating that very bright image
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that washes out the planet.
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So to see the planet,
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we have to do something about all of that light.
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We have to get rid of it.
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I have a lot of colleagues working on
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really amazing technologies to do that,
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but I want to tell you about one today
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that I think is the coolest,
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and probably the most likely to get us an Earth
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in the next decade.
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It was first suggested by Lyman Spitzer,
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the father of the space telescope, in 1962,
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and he took his inspiration from an eclipse.
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You've all seen that. That's a solar eclipse.
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The moon has moved in front of the sun.
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It blocks out most of the light
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so we can see that dim corona around it.
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It would be the same thing if I put my thumb up
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and blocked that spotlight
that's getting right in my eye,
that's getting right in my eye,
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I can see you in the back row.
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Well, what's going on?
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Well the moon
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is casting a shadow down on the Earth.
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We put a telescope or a camera in that shadow,
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we look back at the sun,
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and most of the light's been removed
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and we can see that dim, fine structure
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in the corona.
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Spitzer's suggestion was we do this in space.
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We build a big screen, we fly it in space,
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we put it up in front of the star,
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we block out most of the light,
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we fly a space telescope in
that shadow that's created,
that shadow that's created,
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and boom, we get to see planets.
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Well that would look something like this.
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So there's that big screen,
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and there's no planets,
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because unfortunately it doesn't
actually work very well,
actually work very well,
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because the light waves of the light and waves
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diffracts around that screen
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the same way it did in the telescope.
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It's like water bending around a rock in a stream,
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and all that light just destroys the shadow.
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It's a terrible shadow. And we can't see planets.
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But Spitzer actually knew the answer.
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If we can feather the edges, soften those edges
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so we can control diffraction,
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well then we can see a planet,
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and in the last 10 years or so we've come up
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with optimal solutions for doing that.
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It looks something like that.
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We call that our flower petal starshade.
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If we make the edges of those petals exactly right,
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if we control their shape,
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we can control diffraction,
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and now we have a great shadow.
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It's about 10 billion times dimmer than it was before,
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and we can see the planets beam out just like that.
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That, of course, has to be bigger than my thumb.
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That starshade is about
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the size of half a football field
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and it has to fly 50,000 kilometers
away from the telescope
away from the telescope
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that has to be held right in its shadow,
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and then we can see those planets.
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This sounds formidable,
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but brilliant engineers, colleagues of mine at JPL,
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came up with a fabulous design for how to do that
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and it looks like this.
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It starts wrapped around a hub.
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It separates from the telescope.
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The petals unfurl, they open up,
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the telescope turns around.
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Then you'll see it flip and fly out
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that 50,000 kilometers away from the telescope.
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It's going to move in front of the star
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just like that, creates a wonderful shadow.
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Boom, we get planets orbiting about it.
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(Applause)
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Thank you.
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That's not science fiction.
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We've been working on this
for the last five or six years.
for the last five or six years.
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Last summer, we did a really cool test
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out in California at Northrop Grumman.
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So those are four petals.
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This is a sub-scale star shade.
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It's about half the size of the one you just saw.
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You'll see the petals unfurl.
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Those four petals were built by four undergraduates
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doing a summer internship at JPL.
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Now you're seeing it deploy.
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Those petals have to rotate into place.
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The base of those petals
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has to go to the same place every time
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to within a tenth of a millimeter.
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We ran this test 16 times,
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and 16 times it went into the exact same place
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to a tenth of a millimeter.
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This has to be done very precisely,
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but if we can do this, if we can build this technology,
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if we can get it into space,
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you might see something like this.
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That's a picture of one our nearest neighbor stars
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taken with the Hubble Space Telescope.
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If we can take a similar space telescope,
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slightly larger,
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put it out there,
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fly an occulter in front of it,
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what we might see is something like that --
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that's a family portrait of our
solar system -- but not ours.
solar system -- but not ours.
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We're hoping it'll be someone else's solar system
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as seen through an occulter,
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through a starshade like that.
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You can see Jupiter, you can see Saturn,
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Uranus, Neptune, and right there in the center,
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next to the residual light
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is that pale blue dot. That's Earth.
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We want to see that, see if there's water,
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oxygen, ozone,
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the things that might tell us that it could harbor life.
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I think this is the coolest possible science.
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That's why I got into doing this,
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because I think that will change the world.
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That will change everything when we see that.
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Thank you.
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(Applause)
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ABOUT THE SPEAKER
Jeremy Kasdin - Planet finderUsing innovative orbiting instruments, aerospace engineer Jeremy Kasdin hunts for the universe’s most elusive objects — potentially habitable worlds.
Why you should listen
At Princeton’s High Contrast Imaging Laboratory, Jeremy Kasdin is collaborating on a revolutionary space-based observatory that will unveil previously unseen (and possibly Earth-like) planets in other solar systems.
One of the observatory’s startling innovations is the starshade, an orbiting "occulter" that blocks light from distant stars that ordinarily outshine their dim planets, making a clear view impossible. When paired with a space telescope, the starshade adds a new and powerful instrument to NASA’s cosmic detection toolkit.
More profile about the speakerOne of the observatory’s startling innovations is the starshade, an orbiting "occulter" that blocks light from distant stars that ordinarily outshine their dim planets, making a clear view impossible. When paired with a space telescope, the starshade adds a new and powerful instrument to NASA’s cosmic detection toolkit.
Jeremy Kasdin | Speaker | TED.com