Voice Off Screen: Our cosmic neighborhood just got a little more crowded, NASA just announced it has
discovered seven Earth sized planets orbiting a star that's only
forty light years away. The findings from NASA's Spitzer
Space Telescope also found that three of these planets are in the habitable zone, where
liquid water might flow on it's surface. This is very exciting news
and here to tell us more about this result and what's next is
Dr. Paul Hertz at NASA's Goddard Space Flight Center, thanks for joining us.
Dr. Paul Hertz: You're welcome. Voice Off Screen: So start by telling us about these results
Dr. Paul Hertz: Well yesterday we announced that we have discovered seven Earth sized planets orbiting the same star
and three of these planets are the right distance from the star so
their temperatures are such that they could support liquid water on the surface.
Now this star is not like our Sun, it's only one tenth as large and is much
fainter, so these seven planets are squeezed around that star
closer than Mercury is to the Sun, but even so
they're getting the right amount of light so that they could support life as we know it
were that life to be there.
Voice Off Screen: Forty light years away, I mean it's still far but it's relatively close in cosmic terms
can you talk about how we're able to tell if any
of these planets might be similar to Earth? Dr. Paul Hertz: Sure, astronomers have
come up with this very clever way of studying planets around other stars.
As the planet orbits the star, it passes in front of the star blocking out
a tiny amount of light. By measuring how much light that blocks
out, we know how big the planet is; by measuring how long it is until it
blocks out light again we can measure how long it's year is, and that tells
us how far from the star it is and how much sunlight it gets. So this tells us
how big it is, it's Earth size, tells us how much sunlight it gets
It's Earth-like temperature that puts it firmly in the area of planets that
might be able to have water on their surface.
Voice Off Screen: Now it wasn't that long ago really that we didn't even know if there were
planets orbiting other stars. We figured there probably were
be, can you talk about how some of NASA's
space telescopes, Hubble and Spitzer, are
you know, looking at these exoplanets and determining their atmospheres?
Dr. Paul Hertz: Well now that we know those planets are there we can use the NASA
space telescopes to study them, so we're studying these planets with Hubble and Spitzer
looking for the light as it passes through those
star's atmospheres and that tells us something about those planets. Next year
we'll be launching the TESS satellite and that's going
to scan the entire sky looking for more stars and more planets
like the ones we announced yesterday. And at the end of next year we'll be
launching the James Webb Space Telescope, the largest space telescope
that NASA has ever launched with its very large mirror and exquisite optics
we'll be able to study these planets and planets around other stars
in much more detail than we have before and we'll be able to study
the planet's atmospheres in great detail looking for molecules
in those atmospheres that on Earth indicate the presence of life.
Molecules like Oxygen, Water, Methane.
Voice Off Screen: Tell us a little about, you know as far as this
discovery, talk about what that was like when you
heard there were seven Earth sized planets orbiting
this relatively close star. Dr. Paul Hertz: Well when I was a
astronomy student, we didn't know of any planets around stars other than our own
Sun. I was skeptical like many other astronomers
that we would ever be able to discover and study them even if
they were there. Twenty years ago we were able to discover the very first exoplanet
and in twenty years we've found over five thousand of them.
So we've come to understand that they're out there and we can study them.
But yesterday's announcement with seven Earth-sized planets in the same,
around the same star means that, not only does every star probably
have a planet, every star probably has many planets
that are rocky and in the habitable zone meaning there are billions
of places where life might arise.
We'll start looking at them but the fact that there are so many of them just
boggles the imagination about what are the chances that life is out there?
Voice Off Screen: This is very, very exciting, where can we find more about
the recent results and any updates as we go forward?
Dr. Paul Hertz: Well NASA makes all of it's discoveries about exoplanets available at our website
nasa.gov/exoplanets