I'm here to tell you about the real search
for alien life.
Not little green humanoids arriving in shiny UFOs,
although that would be nice.
But it's the search for planets
orbiting stars far away.
Every star in our sky is a sun.
And if uur sun has planets --
Mercury, Venus, Earth, Mars, etc.
Surely those other stars should have planets also
-- and they do.
And in the last two decades,
astronomers have found thousands of exoplanets.
Our night sky is literally teeming with exoplanets.
We know, statistically speaking,
that every star has at least one planet.
And in the search for planets,
and in the future, planets that might be like earth,
we're able to help address
some of the most amazing and mysterious questions
that have faced humankind for centuries.
Why are we here?
Why does our universe exist?
How did earth form and evolve?
How and why did life originate and populate our planet?
The second question that we often think about
is are we alone?
Is there life out there?
Who is out there?
You know, this question has been around
for thousands of years,
since at least the time of the Greek philosophers.
But, I'm here to tell you just how close we're getting
to finding out the answer to this question.
It's the first time in human history
that this really is within reach for us.
Now when I think about the possibilities
for life out there,
I think of the fact that our sun
is one but many stars.
This is a photograph of a real galaxy,
we think our milky way looks like this galaxy.
It's a collection of bound stars.
But our milky way is one of hundreds of billions of stars
and our galaxy is one of upwards of hundreds of billions of galaxies.
Knowing that small planets are very common,
you can just do the math.
And there are just so many stars and so many planets out there,
that surely, there must be life somewhere out there.
Well, the biologists get furious with me for saying that,
because we have absolutely no evidence
for life beyond earth, yet.
Well, if we were able to look at our galaxy from the outside
and zoom in to where our sun is,
we see a real map of the stars.
And the highlighted stars are ones with known exoplanets,
this is really just the tip of the iceberg.
Here, this animation is zooming in onto our solar system.
And you'll see here some planets as well as some spacecraft
that are also orbiting our sun.
Now if we can imagine going to the west coast
of North America and looking out on the night sky,
here's what we'd see on a spring night.
And you can see the constellations overlaid
and again, so many stars with planets.
There's a special patch of the sky
where we have thousands of planets.
This is where the Kepler Space Telescope focused for many years.
Let's zoom in and look at one of the favorite exoplanets.
This star is called Kepler 180-6F.
It's a system of about five planets.
And by the way, most of these exoplanets,
we don't know too much about.
We know their size, and their orbit and things like that.
But there's a very special planet here called Kepler 180-6F,
this planet is in a zone that is not too far from the star,
so that the temperature may be just right for life.
Here, the artist conniption is just zooming in
and showing you what that planet might be like.
So, many people have this romantic notion of astronomers
going to a telescope on a lonely mountaintop
and looking at the spectacular night sky
through a big telescope.
But actually, we just work on our computers like everyone else
and we get our data by email or by loading from a database.
So instead of coming here to tell you about
the somewhat tedious nature of the data and data analysis
and the complex computer models we make,
I have a different way to try to explain to you
some of the things that we're thinking about exoplanets.
Here's a travel poster:
"Kepler-186f,
Where the grass is always redder on the other side."
That's because Kepler-186f is a red star,
and we're just speculating that perhaps the plants there,
if there is vegetation that does photosynthesis,
it has different pigments and looks red.
Enjoy the gravity on HD 40307g,
a super-earth.
This planet is more massive than earth
and has a higher surface gravity.
Relax on Kepler-16b,
where your shadow always has company.
We know of a dozen planets that orbit two stars,
and there's likely many more out there.
If we could visit one of those planets,
you literally would see two sunsets
and have two shadows.
So actually, science fiction got some things right,
Tatooine from Star Wars.
And I have a couple of other favorite exoplanets
to tell you about.
This one is Kepler-10b,
it's a hot, hot planet.
It orbits over 50 times closer to its star
than the earth does to our sun.
And actually, it's so hot
we can't visit any of these planets,
but if we could,
we would melt long before we got there.
We think the surface is hot enough to melt rock
and has liquid lava lakes.
We use 1214b,
this planet,
we know the mass and the size
and it has a fairly low density,
it's somewhat warm.
We actually