This new telescope might show us the beginning of the universe | Wendy Freedman

120,241 views ・ 2015-09-22

TED


Please double-click on the English subtitles below to play the video.

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When I was 14 years old, I was interested in science --
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fascinated by it, excited to learn about it.
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And I had a high school science teacher who would say to the class,
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"The girls don't have to listen to this."
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Encouraging, yes.
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(Laughter)
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I chose not to listen -- but to that statement alone.
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So let me take you to the Andes mountains in Chile,
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500 kilometers, 300 miles northeast of Santiago.
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It's very remote, it's very dry and it's very beautiful.
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And there's not much there.
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There are condors, there are tarantulas,
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and at night, when the light dims,
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it reveals one of the darkest skies on Earth.
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It's kind of a magic place, the mountain.
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It's a wonderful combination of very remote mountaintop
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with exquisitely sophisticated technology.
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And our ancestors, for as long as there's been recorded history,
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have looked at the night sky and pondered the nature of our existence.
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And we're no exception, our generation.
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The only difficulty is that the night sky now is blocked
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by the glare of city lights.
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And so astronomers go to these very remote mountaintops
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to view and to study the cosmos.
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So telescopes are our window to the cosmos.
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It's no exaggeration to say that the Southern Hemisphere is going to be
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the future of astronomy for the 21st century.
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We have an array of existing telescopes already,
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in the Andes mountains in Chile,
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and that's soon to be joined by a really sensational array of new capability.
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There will be two international groups that are going to be building
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giant telescopes, sensitive to optical radiation, as our eyes are.
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There will be a survey telescope
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that will be scanning the sky every few nights.
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There will be radio telescopes,
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sensitive to long-wavelength radio radiation.
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And then there will be telescopes in space.
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There'll be a successor to the Hubble Space Telescope;
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it's called the James Webb Telescope,
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and it will be launched in 2018.
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There'll be a satellite called TESS
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that will discover planets outside of our solar system.
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For the last decade, I've been leading a group --
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a consortium -- international group,
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to build what will be, when it's finished,
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the largest optical telescope in existence.
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It's called the Giant Magellan Telescope, or GMT.
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This telescope is going to have mirrors that are 8.4 meters in diameter --
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each of the mirrors.
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That's almost 27 feet.
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So it dwarfs this stage -- maybe out to the fourth row in this audience.
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Each of the seven mirrors in this telescope
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will be almost 27 feet in diameter.
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Together, the seven mirrors in this telescope will comprise
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80 feet in diameter.
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So, essentially the size of this entire auditorium.
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The whole telescope will stand about 43 meters high,
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and again, being in Rio,
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some of you have been to see the statue of the giant Christ.
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The scale is comparable in height;
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in fact, it's smaller than this telescope will be.
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It's comparable to the size of the Statue of Liberty.
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And it's going to be housed in an enclosure that's 22 stories --
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60 meters high.
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But it's an unusual building to protect this telescope.
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It will have open windows to the sky,
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be able to point and look at the sky,
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and it will actually rotate on a base --
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2,000 tons of rotating building.
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The Giant Magellan Telescope will have 10 times the resolution
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of the Hubble Space Telescope.
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It will be 20 million times more sensitive than the human eye.
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And it may, for the first time ever, be capable of finding life on planets
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outside of our solar system.
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It's going to allow us to look back at the first light in the universe --
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literally, the dawn of the cosmos.
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The cosmic dawn.
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It's a telescope that's going to allow us to peer back,
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witness galaxies as they were when they were actually assembling,
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the first black holes in the universe, the first galaxies.
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Now, for thousands of years, we have been studying the cosmos,
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we've been wondering about our place in the universe.
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The ancient Greeks told us
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that the Earth was the center of the universe.
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Five hundred years ago, Copernicus displaced the Earth,
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and put the Sun at the heart of the cosmos.
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And as we've learned over the centuries,
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since Galileo Galilei, the Italian scientist,
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first turned, in that time, a two-inch, very small telescope, to the sky,
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every time we have built larger telescopes,
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we have learned something about the universe;
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we've made discoveries, without exception.
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We've learned in the 20th century that the universe is expanding
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and that our own solar system is not at the center of that expansion.
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We know now that the universe is made of about 100 billion galaxies
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that are visible to us,
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and each one of those galaxies has 100 billion stars within it.
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So we're looking now at the deepest image of the cosmos
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that's ever been taken.
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It was taken using the Hubble Space Telescope,
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and by pointing the telescope at what was previously a blank region of sky,
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before the launch of Hubble.
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And if you can imagine this tiny area,
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it's only one-fiftieth of the size of the full moon.
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So, if you can imagine the full moon.
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And there are now 10,000 galaxies visible within that image.
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And the faintness of those images and the tiny size is only a result
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of the fact that those galaxies are so far away, the vast distances.
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And each of those galaxies may contain within it
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a few billion or even hundreds of billions of individual stars.
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Telescopes are like time machines.
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So the farther back we look in space, the further back we see in time.
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And they're like light buckets -- literally, they collect light.
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So larger the bucket, the larger the mirror we have,
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the more light we can see, and the farther back we can view.
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So, we've learned in the last century
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that there are exotic objects in the universe -- black holes.
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We've even learned that there's dark matter and dark energy
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that we can't see.
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So you're looking now at an actual image of dark matter.
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(Laughter)
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You got it. Not all audiences get that.
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(Laughter)
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So the way we infer the presence of dark matter --
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we can't see it -- but there's an unmistakable tug, due to gravity.
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We now can look out, we see this sea of galaxies
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in a universe that's expanding.
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What I do myself is to measure the expansion of the universe,
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and one of the projects that I carried out in the 1990s
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used the Hubble Space Telescope to measure how fast the universe is expanding.
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We can now trace back to 14 billion years.
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We've learned over time that stars have individual histories;
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that is, they have birth, they have middle ages
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and some of them even have dramatic deaths.
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So the embers from those stars actually then form the new stars that we see,
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most of which turn out to have planets going around them.
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And one of the really surprising results in the last 20 years
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has been the discovery of other planets going around other stars.
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These are called exoplanets.
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And until 1995, we didn't even know the existence of any other planets,
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other than going around our own sun.
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But now, there are almost 2,000 other planets orbiting other stars
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that we can now detect, measure masses for.
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There are 500 of those that are multiple-planet systems.
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And there are 4,000 -- and still counting -- other candidates
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for planets orbiting other stars.
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They come in a bewildering variety of different kinds.
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There are Jupiter-like planets that are hot,
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there are other planets that are icy, there are water worlds
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and there are rocky planets like the Earth, so-called "super-Earths,"
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and there have even been planets that have been speculated diamond worlds.
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So we know there's at least one planet, our own Earth, in which there is life.
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We've even found planets that are orbiting two stars.
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That's no longer the province of science fiction.
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So around our own planet, we know there's life,
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we've developed a complex life, we now can question our own origins.
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And given all that we've discovered, the overwhelming numbers now suggest
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that there may be millions, perhaps -- maybe even hundreds of millions --
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of other [planets] that are close enough --
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just the right distance from their stars that they're orbiting --
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to have the existence of liquid water and maybe could potentially support life.
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So we marvel now at those odds, the overwhelming odds,
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and the amazing thing is that within the next decade,
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the GMT may be able to take spectra of the atmospheres of those planets,
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and determine whether or not they have the potential for life.
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So, what is the GMT project?
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It's an international project.
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It includes Australia, South Korea, and I'm happy to say, being here in Rio,
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that the newest partner in our telescope is Brazil.
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(Applause)
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It also includes a number of institutions across the United States,
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including Harvard University,
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the Smithsonian and the Carnegie Institutions,
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and the Universities of Arizona, Chicago, Texas-Austin and Texas A&M University.
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It also involves Chile.
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So, the making of the mirrors in this telescope is also fascinating
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in its own right.
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Take chunks of glass, melt them in a furnace that is itself rotating.
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This happens underneath the football stadium
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at the University of Arizona.
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It's tucked away under 52,000 seats.
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Nobody know it's happening.
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And there's essentially a rotating cauldron.
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The mirrors are cast and they're cooled very slowly,
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and then they're polished to an exquisite precision.
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And so, if you think about the precision of these mirrors,
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the bumps on the mirror, over the entire 27 feet,
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amount to less than one-millionth of an inch.
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So, can you visualize that?
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Ow!
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(Laughter)
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That's one five-thousandths of the width of one of my hairs,
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over this entire 27 feet.
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It's a spectacular achievement.
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It's what allows us to have the precision that we will have.
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So, what does that precision buy us?
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So the GMT, if you can imagine --
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if I were to hold up a coin, which I just happen to have,
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and I look at the face of that coin, I can see from here
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the writing on the coin; I can see the face on that coin.
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My guess that even in the front row, you can't see that.
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But if we were to turn the Giant Magellan Telescope,
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all 80-feet diameter that we see in this auditorium,
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and point it 200 miles away,
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if I were standing in São Paulo, we could resolve the face of this coin.
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That's the extraordinary resolution and power of this telescope.
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And if we were --
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(Applause)
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If an astronaut went up to the Moon, a quarter of a million miles away,
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and lit a candle -- a single candle --
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then we would be able to detect it, using the GMT.
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Quite extraordinary.
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This is a simulated image of a cluster in a nearby galaxy.
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"Nearby" is astronomical, it's all relative.
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It's tens of millions of light-years away.
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This is what this cluster would look like.
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So look at those four bright objects,
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and now lets compare it with a camera on the Hubble Space Telescope.
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You can see faint detail that starts to come through.
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And now finally -- and look how dramatic this is -- this is what the GMT will see.
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So, keep your eyes on those bright images again.
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This is what we see on one of the most powerful existing telescopes on the Earth,
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and this, again, what the GMT will see.
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Extraordinary precision.
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So, where are we?
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We have now leveled the top of the mountaintop in Chile.
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We blasted that off.
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We've tested and polished the first mirror.
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We've cast the second and the third mirrors.
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And we're about to cast the fourth mirror.
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We had a series of reviews this year,
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international panels that came in and reviewed us,
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and said, "You're ready to go to construction."
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And so we plan on building this telescope with the first four mirrors.
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We want to get on the air quickly, and be taking science data --
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what we astronomers call "first light," in 2021.
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And the full telescope will be finished in the middle of the next decade,
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with all seven mirrors.
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So we're now poised to look back at the distant universe,
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the cosmic dawn.
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We'll be able to study other planets in exquisite detail.
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But for me, one of the most exciting things about building the GMT
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is the opportunity to actually discover something
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that we don't know about -- that we can't even imagine at this point,
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something completely new.
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And my hope is that with the construction of this and other facilities,
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that many young women and men will be inspired to reach for the stars.
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Thank you very much.
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Obrigado.
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(Applause)
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Bruno Giussani: Thank you, Wendy.
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Stay with me, because I have a question for you.
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You mentioned different facilities.
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So the Magellan Telescope is going up, but also ALMA and others in Chile
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and elsewhere, including in Hawaii.
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Is it about cooperation and complementarity, or about competition?
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I know there's competition in terms of funding, but what about the science?
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Wendy Freedman: In terms of the science, they're very complementary.
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The telescopes that are in space, the telescopes on the ground,
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telescopes with different wavelength capability,
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telescopes even that are similar, but different instruments --
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they will all look at different parts of the questions that we're asking.
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So when we discover other planets, we'll be able to test those observations,
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we'll be able to measure the atmospheres,
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be able to look in space with very high resolution.
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So, they're very complementary.
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You're right about the funding, we compete;
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but scientifically, it's very complementary.
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BG: Wendy, thank you very much for coming to TEDGlobal.
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WF: Thank you.
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(Applause)
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