9:59:59.000,9:59:59.000
I'm here to tell you about[br]the real search

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for alien life.

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Not little green humanoids[br]arriving in shiny UFOs,

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although that would be nice.

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But it's the search for planets

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orbiting stars far away.

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Every star in our sky is a sun.

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And if uur sun has planets --

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Mercury, Venus, Earth, Mars, etc.

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Surely those other stars should[br]have planets also

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-- and they do.

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And in the last two decades,

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astronomers have found[br]thousands of exoplanets.

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Our night sky is literally[br]teeming with exoplanets.

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We know, statistically speaking,

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that every star has at least one planet.

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And in the search for planets,

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and in the future, planets [br]that might be like earth,

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we're able to help address[br]

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some of the most amazing[br]and mysterious questions

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that have faced humankind for centuries.

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Why are we here?

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Why does our universe exist?

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How did earth form and evolve?

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How and why did life originate[br]and populate our planet?

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The second question[br]that we often think about

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is are we alone?

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Is there life out there?

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Who is out there?

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You know, this question[br]has been around

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for thousands of years,

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since at least the time[br]of the Greek philosophers.

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But, I'm here to tell you[br]just how close we're getting

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to finding out the answer[br]to this question.

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It's the first time in human history

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that this really is within reach for us.

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Now when I think about[br]the possibilities

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for life out there,

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I think of the fact that our sun

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is one but many stars.

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This is a photograph of a real galaxy,

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we think our milky way [br]looks like this galaxy.

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It's a collection of bound stars.

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But our milky way is one of[br]hundreds of billions of stars

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and our galaxy is one of upwards[br]of hundreds of billions of galaxies.

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Knowing that small planets [br]are very common,

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you can just do the math.

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And there are just so many stars[br]and so many planets out there,

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that surely, there must be life[br]somewhere out there.

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Well, the biologists get furious [br]with me for saying that,

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because we have absolutely[br]no evidence

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for life beyond earth, yet.

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Well, if we were able to look[br]at our galaxy from the outside

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and zoom in to where our sun is,

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we see a real map of the stars.

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And the highlighted stars[br]are ones with known exoplanets,

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this is really just[br]the tip of the iceberg.

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Here, this animation is zooming in[br]onto our solar system.

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And you'll see here some planets[br]as well as some spacecraft

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that are also orbiting our sun.

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Now if we can imagine[br]going to the west coast

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of North America and looking out[br]on the night sky,

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here's what we'd see on a spring night.

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And you can see[br]the constellations overlaid

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and again, so many stars with planets.

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There's a special patch of the sky

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where we have thousands of planets.

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This is where the Kepler Space Telescope[br]focused for many years.

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Let's zoom in and look at[br]one of the favorite exoplanets.

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This star is called Kepler 180-6F.

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It's a system of about five planets.

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And by the way, most of these exoplanets,

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we don't know too much about.

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We know their size, and their orbit[br]and things like that.

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But there's a very special planet[br]here called Kepler 180-6F,

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this planet is in a zone that is not [br]too far from the star,

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so that the temperature may be [br]just right for life.

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Here, the artist conniption is just[br]zooming in

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and showing you what that planet[br]might be like.

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So, many people have this[br]romantic notion of astronomers

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going to a telescope[br]on a lonely mountaintop

9:59:59.000,9:59:59.000
and looking at the spectacular night sky

9:59:59.000,9:59:59.000
through a big telescope.

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But actually, we just work on[br]our computers like everyone else

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and we get our data by email[br]or by loading from a database.

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So instead of coming here to tell you[br]about

9:59:59.000,9:59:59.000
the somewhat tedious nature of the data[br]and data analysis

9:59:59.000,9:59:59.000
and the complex computer models we make,

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I have a different way to try to explain[br]to you

9:59:59.000,9:59:59.000
some of the things that we're [br]thinking about exoplanets.

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Here's a travel poster:

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"Kepler-186f,

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Where the grass is always redder [br]on the other side."

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That's because Kepler-186f[br]is a red star,

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and we're just speculating that[br]perhaps the plants there,

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if there is vegetation that [br]does photosynthesis,

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it has different pigments and looks red.

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Enjoy the gravity on HD 40307g,

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a super-earth.

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This planet is more massive than earth

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and has a higher surface gravity.

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Relax on Kepler-16b,

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where your shadow always has company.

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We know of a dozen planets[br]that orbit two stars,

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and there's likely many more out there.

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If we could visit one of those planets,

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you literally would see two sunsets

9:59:59.000,9:59:59.000
and have two shadows.

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So actually, science fiction [br]got some things right,

9:59:59.000,9:59:59.000
Tatooine from Star Wars.

9:59:59.000,9:59:59.000
And I have a couple of other [br]favorite exoplanets

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to tell you about.

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This one is Kepler-10b,

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it's a hot, hot planet.

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It orbits over 50 times closer[br]to its star

9:59:59.000,9:59:59.000
than the earth does to our sun.

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And actually, it's so hot

9:59:59.000,9:59:59.000
we can't visit any of these planets,

9:59:59.000,9:59:59.000
but if we could,

9:59:59.000,9:59:59.000
we would melt long before[br]we got there.

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We think the surface is hot enough[br]to melt rock

9:59:59.000,9:59:59.000
and has liquid lava lakes.

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We use 1214b,

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this planet,

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we know the mass and the size

9:59:59.000,9:59:59.000
and it has a fairly low density,

9:59:59.000,9:59:59.000
it's somewhat warm.

9:59:59.000,9:59:59.000
We actually