[slate]
So exoplanets are planets
outside of our solar system, they're orbiting other stars
and that makes them very far away. So it's very difficult
to observe details about exoplanets. We have to use special
techniques to do that. The way we have used the Hubble Space
Telescope to understand atmospheres of exoplanets is
to look at those planets as they orbit around their parent star
and when they sort of transit in front of that parent star, some of that starlight comes
through the atmosphere surrounding the planet. And the atmosphere
may absorb some of that light. And we can tell from the spectroscopic
patterns of that light absorption what's in the atmosphere.
In this case scientists have used the Hubble in this way to look at the spectroscopic
signature of a planet transiting in front of its parent
star to detect the signature of water vapor
in the atmosphere of that exoplanet. And this is exciting news because it's not
the first time we've seen water vapor in an exoplanet. There's some very
large planets, big Jupiter-sized things that we've seen water vapor in.
But this time, this planet is what we call a super-Earth. It's about eight times
the mass of the Earth, which sounds big, but that's still a kind
of planet that might be somewhat similar to Earth. And it also
distance from its star where we might have moderate temperatures that would allow
for liquid water and potentially habitability of that planet.
So it's the next step in our investigations of exoplanets
to see if any of them are like the planets in our own solar system.
[slate]
We don't know whether or not there could be life on
this exoplanet. This is a next step in kind of studying what
exoplanets are like. We're trying to understand if any of them could be
very similar to Earth and could be habitable for life.
One piece of that equation is to find planets like this one
where the temperature might be moderate enough to allow water
to be in liquid form - not so cold that it's frozen as ice
or so hot that it boils away. This planet seems to be at that
Goldilocks distance from its parent star to have potentially have
liquid water and now we've seen water vapor in its atmosphere. But that's not
the only characteristic of a planet that might be habitable.
We also are concerned that the star that this planet is
orbiting is probably very active. It's what we call a dwarf star.
It may have some flaring. The planet is closer to its star
than Earth is to our bigger sun. And it means that there might be heavy
radiation coming on this planet which might it difficult for advanced life
to thrive. We just don't know. But we've made this next step
now of finding a super Earth with water vapor in the atmosphere and that's
an exciting step to make.
[slate]
Well thanks to telescopes
both on the ground and telescopes in space such as
NASA's Kepler Space Telescope we understand that planets
are quiet common in our galaxy. In fact many,
if not most stars have at least one planet. Now those planets may
not be similar to planet Earth, but planets themselves seem to be common.
And so it's likely that there are
millions and possibly billions of Earth
or super-Earth sized exoplanets in the galaxy or
orbiting other stars but most of them are very far away and very difficult
for us to learn any great details about those exoplanets.
We're better off looking at the near-by stars to find
details, and we're doing that with some other NASA facilities as well
like the TESS mission which is looking at planets round very bright stars in our
neighborhood around the sun. And this information all works together
to tell us some of the details of some of these exoplanets.
But we believe exoplanets are very common and even Earth-mass,
Earth-sized planets are probably fairly common in our galaxy.
[slate]
This particular planet is
110 light years away. That means it's taken over
100 years for the light from that system just to even get to our Hubble
Space Telescope. For us to travel there would take
many lifetimes. We don't have the technology yet
to actually send a probe or any kind of mission to this
system. So the way we are studying is by
receiving the light from the star as it kind of comes through
the atmosphere around the exoplanet as the planet orbits in front of the star
And we can see what's in that atmosphere based on what the atmosphere absorbs from
that starlight. That is the way we can explore this system with our current technology.
[slate]
Well we've used the Hubble Space Telescope
for all of its mission basically to study planets
in our own solar system. We have beautiful images of Jupiter
and Saturn and we've also been studying their atmospheres.
And the characteristics of their moons. But we're now using
Hubble also to look at other star systems
and their planets. When Hubble was launched back in 1990 we weren't even sure that
there were abundance of planets around other stars. Hubble was not designed
to do this kind of work. And yet now scientists are using Hubble to
study the very compositions of atmospheres of planets orbiting
other stars. We'd like to know how other planetary systems
compare to our own solar system. And that is something Hubble is terrific at.
[slate]
[slate] The Hubble Space Telescope
is turning 30 years old in 2020
and it is in fantastic shape. The team
of engineers and technical experts that oversee Hubble
have kept it operating in tip top shape and we're grateful to astronauts who
have returned to the Hubble several times over its mission to keep it
refreshed with good instruments and supporting capabilities
So right now we are getting the strongest science from the Hubble Space Telescope
than we ever have and we expect that to continue for quite
a few more years to come. In fact we're looking forward to an overlap of
some years between the Hubble Space Telescope and the new James Webb
Space Telescope that will launch in 2021. These telescopes
will be complementary in terms of the information we get from them
covering a spectrum of light all the way from what Hubble can see in the ultraviolet
and visible parts of the light spectrum to the infrared
part of the spectrum that Hubble can see and also the James Webb
much deeper into the infrared part of the light spectrum. This teaches us
a lot about exoplanets, about the stars
that they orbit. About how they form and even about
very distant star systems as well.