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  • When I was 14 years old, I was interested in science --

  • fascinated by it, excited to learn about it.

  • And I had a high school science teacher who would say to the class,

  • "The girls don't have to listen to this."

  • Encouraging, yes.

  • (Laughter)

  • I chose not to listen -- but to that statement alone.

  • So let me take you to the Andes mountains in Chile,

  • 500 kilometers, 300 miles northeast of Santiago.

  • It's very remote, it's very dry and it's very beautiful.

  • And there's not much there.

  • There are condors, there are tarantulas,

  • and at night, when the light dims,

  • it reveals one of the darkest skies on Earth.

  • It's kind of a magic place, the mountain.

  • It's a wonderful combination of very remote mountaintop

  • with exquisitely sophisticated technology.

  • And our ancestors, for as long as there's been recorded history,

  • have looked at the night sky and pondered the nature of our existence.

  • And we're no exception, our generation.

  • The only difficulty is that the night sky now is blocked

  • by the glare of city lights.

  • And so astronomers go to these very remote mountaintops

  • to view and to study the cosmos.

  • So telescopes are our window to the cosmos.

  • It's no exaggeration to say that the Southern Hemisphere is going to be

  • the future of astronomy for the 21st century.

  • We have an array of existing telescopes already,

  • in the Andes mountains in Chile,

  • and that's soon to be joined by a really sensational array of new capability.

  • There will be two international groups that are going to be building

  • giant telescopes, sensitive to optical radiation, as our eyes are.

  • There will be a survey telescope

  • that will be scanning the sky every few nights.

  • There will be radio telescopes,

  • sensitive to long-wavelength radio radiation.

  • And then there will be telescopes in space.

  • There'll be a successor to the Hubble Space Telescope;

  • it's called the James Webb Telescope,

  • and it will be launched in 2018.

  • There'll be a satellite called TESS

  • that will discover planets outside of our solar system.

  • For the last decade, I've been leading a group --

  • a consortium -- international group,

  • to build what will be, when it's finished,

  • the largest optical telescope in existence.

  • It's called the Giant Magellan Telescope, or GMT.

  • This telescope is going to have mirrors that are 8.4 meters in diameter --

  • each of the mirrors.

  • That's almost 27 feet.

  • So it dwarfs this stage -- maybe out to the fourth row in this audience.

  • Each of the seven mirrors in this telescope

  • will be almost 27 feet in diameter.

  • Together, the seven mirrors in this telescope will comprise

  • 80 feet in diameter.

  • So, essentially the size of this entire auditorium.

  • The whole telescope will stand about 43 meters high,

  • and again, being in Rio,

  • some of you have been to see the statue of the giant Christ.

  • The scale is comparable in height;

  • in fact, it's smaller than this telescope will be.

  • It's comparable to the size of the Statue of Liberty.

  • And it's going to be housed in an enclosure that's 22 stories --

  • 60 meters high.

  • But it's an unusual building to protect this telescope.

  • It will have open windows to the sky,

  • be able to point and look at the sky,

  • and it will actually rotate on a base --

  • 2,000 tons of rotating building.

  • The Giant Magellan Telescope will have 10 times the resolution

  • of the Hubble Space Telescope.

  • It will be 20 million times more sensitive than the human eye.

  • And it may, for the first time ever, be capable of finding life on planets

  • outside of our solar system.

  • It's going to allow us to look back at the first light in the universe --

  • literally, the dawn of the cosmos.

  • The cosmic dawn.

  • It's a telescope that's going to allow us to peer back,

  • witness galaxies as they were when they were actually assembling,

  • the first black holes in the universe, the first galaxies.

  • Now, for thousands of years, we have been studying the cosmos,

  • we've been wondering about our place in the universe.

  • The ancient Greeks told us

  • that the Earth was the center of the universe.

  • Five hundred years ago, Copernicus displaced the Earth,

  • and put the Sun at the heart of the cosmos.

  • And as we've learned over the centuries,

  • since Galileo Galilei, the Italian scientist,

  • first turned, in that time, a two-inch, very small telescope, to the sky,

  • every time we have built larger telescopes,

  • we have learned something about the universe;

  • we've made discoveries, without exception.

  • We've learned in the 20th century that the universe is expanding

  • and that our own solar system is not at the center of that expansion.

  • We know now that the universe is made of about 100 billion galaxies

  • that are visible to us,

  • and each one of those galaxies has 100 billion stars within it.

  • So we're looking now at the deepest image of the cosmos

  • that's ever been taken.

  • It was taken using the Hubble Space Telescope,

  • and by pointing the telescope at what was previously a blank region of sky,

  • before the launch of Hubble.

  • And if you can imagine this tiny area,

  • it's only one-fiftieth of the size of the full moon.

  • So, if you can imagine the full moon.

  • And there are now 10,000 galaxies visible within that image.

  • And the faintness of those images and the tiny size is only a result

  • of the fact that those galaxies are so far away, the vast distances.

  • And each of those galaxies may contain within it

  • a few billion or even hundreds of billions of individual stars.

  • Telescopes are like time machines.

  • So the farther back we look in space, the further back we see in time.

  • And they're like light buckets -- literally, they collect light.

  • So larger the bucket, the larger the mirror we have,

  • the more light we can see, and the farther back we can view.

  • So, we've learned in the last century

  • that there are exotic objects in the universe -- black holes.

  • We've even learned that there's dark matter and dark energy

  • that we can't see.

  • So you're looking now at an actual image of dark matter.

  • (Laughter)

  • You got it. Not all audiences get that.

  • (Laughter)

  • So the way we infer the presence of dark matter --

  • we can't see it -- but there's an unmistakable tug, due to gravity.

  • We now can look out, we see this sea of galaxies

  • in a universe that's expanding.

  • What I do myself is to measure the expansion of the universe,

  • and one of the projects that I carried out in the 1990s

  • used the Hubble Space Telescope to measure how fast the universe is expanding.

  • We can now trace back to 14 billion years.

  • We've learned over time that stars have individual histories;

  • that is, they have birth, they have middle ages

  • and some of them even have dramatic deaths.

  • So the embers from those stars actually then form the new stars that we see,

  • most of which turn out to have planets going around them.

  • And one of the really surprising results in the last 20 years

  • has the been the discovery of other planets going around other stars.

  • These are called exoplanets.

  • And until 1995, we didn't even know the existence of any other planets,

  • other than going around our own sun.

  • But now, there are almost 2,000 other planets orbiting other stars

  • that we can now detect, measure masses for.

  • There are 500 of those that are multiple-planet systems.

  • And there are 4,000 -- and still counting -- other candidates

  • for planets orbiting other stars.

  • They come in a bewildering variety of different kinds.

  • There are Jupiter-like planets that are hot,

  • there are other planets that are icy, there are water worlds

  • and there are rocky planets like the Earth, so-called "super-Earths,"

  • and there have even been planets that have been speculated diamond worlds.

  • So we know there's at least one planet, our own Earth, in which there is life.

  • We've even found planets that are orbiting two stars.

  • That's no longer the province of science fiction.

  • So around our own planet, we know there's life,

  • we've developed a complex life, we now can question our own origins.

  • And given all that we've discovered, the overwhelming numbers now suggest

  • that there may be millions, perhaps -- maybe even hundreds of millions --

  • of other [planets] that are close enough --

  • just the right distance from their stars that they're orbiting --

  • to have the existence of liquid water and maybe could potentially support life.

  • So we marvel now at those odds, the overwhelming odds,

  • and the amazing thing is that within the next decade,

  • the GMT may be able to take spectra of the atmospheres of those planets,

  • and determine whether or not they have the potential for life.

  • So, what is the GMT project?

  • It's an international project.

  • It includes Australia, South Korea, and I'm happy to say, being here in Rio,

  • that the newest partner in our telescope is Brazil.

  • (Applause)

  • It also includes a number of institutions across the United States,

  • including Harvard University,

  • the Smithsonian and the Carnegie Institutions,

  • and the Universities of Arizona, Chicago, Texas-Austin and Texas A&M University.

  • It also involves Chile.

  • So, the making of the mirrors in this telescope is also fascinating

  • in its own right.

  • Take chunks of glass, melt them in a furnace that is itself rotating.

  • This happens underneath the football stadium

  • at the University of Arizona.

  • It's tucked away under 52,000 seats.

  • Nobody know it's happening.

  • And there's essentially a rotating cauldron.

  • The mirrors are cast and they're cooled very slowly,

  • and then they're polished to an exquisite precision.

  • And so, if you think about the precision of these mirrors,

  • the bumps on the mirror, over the entire 27 feet,

  • amount to less than one-millionth of an inch.

  • So, can you visualize that?

  • Ow!

  • (Laughter)

  • That's one five-thousandths of the width of one of my hairs,

  • over this entire 27 feet.

  • It's a spectacular achievement.

  • It's what allows us to have the precision that we will have.

  • So, what does that precision buy us?

  • So the GMT, if you can imagine --

  • if I were to hold up a coin, which I just happen to have,

  • and I look at the face of that coin, I can see from here

  • the writing on the coin; I can see the face on that coin.

  • My guess that even in the front row, you can't see that.

  • But if we were to turn the Giant Magellan Telescope,

  • all 80-feet diameter that we see in this auditorium,

  • and point it 200 miles away,

  • if I were standing in São Paulo, we could resolve the face of this coin.

  • That's the extraordinary resolution and power of this telescope.

  • And if we were --

  • (Applause)

  • If an astronaut went up to the Moon, a quarter of a million miles away,

  • and lit a candle -- a single candle --

  • then we would be able to detect it, using the GMT.

  • Quite extraordinary.

  • This is a simulated image of a cluster in a nearby galaxy.

  • "Nearby" is astronomical, it's all relative.

  • It's tens of millions of light-years away.

  • This is what this cluster would look like.

  • So look at those four bright objects,

  • and now lets compare it with a camera on the Hubble Space Telescope.

  • You can see faint detail that starts to come through.

  • And now finally -- and look how dramatic this is -- this is what the GMT will see.

  • So, keep your eyes on those bright images again.

  • This is what we see on one of the most powerful existing telescopes on the Earth,

  • and this, again, what the GMT will see.

  • Extraordinary precision.

  • So, where are we?

  • We have now leveled the top of the mountaintop in Chile.

  • We blasted that off.

  • We've tested and polished the first mirror.

  • We've cast the second and the third mirrors.

  • And we're about to cast the fourth mirror.

  • We had a series of reviews this year,

  • international panels that came in and reviewed us,

  • and said, "You're ready to go to construction."

  • And so we plan on building this telescope with the first four mirrors.

  • We want to get on the air quickly, and be taking science data --

  • what we astronomers call "first light," in 2021.

  • And the full telescope will be finished in the middle of the next decade,

  • with all seven mirrors.

  • So we're now poised to look back at the distant universe,

  • the cosmic dawn.