The search for planets beyond our solar system

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