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Voice Off Screen: Our cosmic neighborhood just got a little more crowded, NASA just announced it has

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discovered seven Earth sized planets orbiting a star that's only

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forty light years away. The findings from NASA's Spitzer

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Space Telescope also found that three of these planets are in the habitable zone, where

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liquid water might flow on it's surface. This is very exciting news

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and here to tell us more about this result and what's next is

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Dr. Paul Hertz at NASA's Goddard Space Flight Center, thanks for joining us.

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Dr. Paul Hertz: You're welcome. Voice Off Screen: So start by telling us about these results

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Dr. Paul Hertz: Well yesterday we announced that we have discovered seven Earth sized planets orbiting the same star

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and three of these planets are the right distance from the star so

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their temperatures are such that they could support liquid water on the surface.

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Now this star is not like our Sun, it's only one tenth as large and is much

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fainter, so these seven planets are squeezed around that star

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closer than Mercury is to the Sun, but even so

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they're getting the right amount of light so that they could support life as we know it

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were that life to be there.

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Voice Off Screen: Forty light years away, I mean it's still far but it's relatively close in cosmic terms

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can you talk about how we're able to tell if any

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of these planets might be similar to Earth? Dr. Paul Hertz: Sure, astronomers have

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come up with this very clever way of studying planets around other stars.

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As the planet orbits the star, it passes in front of the star blocking out

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a tiny amount of light. By measuring how much light that blocks

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out, we know how big the planet is; by measuring how long it is until it

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blocks out light again we can measure how long it's year is, and that tells

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us how far from the star it is and how much sunlight it gets. So this tells us

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how big it is, it's Earth size, tells us how much sunlight it gets

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It's Earth-like temperature that puts it firmly in the area of planets that

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might be able to have water on their surface.

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Voice Off Screen: Now it wasn't that long ago really that we didn't even know if there were

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planets orbiting other stars. We figured there probably were

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be, can you talk about how some of NASA's

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space telescopes, Hubble and Spitzer, are

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you know, looking at these exoplanets and determining their atmospheres?

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Dr. Paul Hertz: Well now that we know those planets are there we can use the NASA

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space telescopes to study them, so we're studying these planets with Hubble and Spitzer

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looking for the light as it passes through those

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star's atmospheres and that tells us something about those planets. Next year

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we'll be launching the TESS satellite and that's going

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to scan the entire sky looking for more stars and more planets

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like the ones we announced yesterday. And at the end of next year we'll be

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launching the James Webb Space Telescope, the largest space telescope

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that NASA has ever launched with its very large mirror and exquisite optics

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we'll be able to study these planets and planets around other stars

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in much more detail than we have before and we'll be able to study

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the planet's atmospheres in great detail looking for molecules

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in those atmospheres that on Earth indicate the presence of life.

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Molecules like Oxygen, Water, Methane.

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Voice Off Screen: Tell us a little about, you know as far as this

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discovery, talk about what that was like when you

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heard there were seven Earth sized planets orbiting

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this relatively close star. Dr. Paul Hertz: Well when I was a

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astronomy student, we didn't know of any planets around stars other than our own

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Sun. I was skeptical like many other astronomers

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that we would ever be able to discover and study them even if

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they were there. Twenty years ago we were able to discover the very first exoplanet

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and in twenty years we've found over five thousand of them.

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So we've come to understand that they're out there and we can study them.

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But yesterday's announcement with seven Earth-sized planets in the same,

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around the same star means that, not only does every star probably

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have a planet, every star probably has many planets

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that are rocky and in the habitable zone meaning there are billions

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of places where life might arise.

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We'll start looking at them but the fact that there are so many of them just

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boggles the imagination about what are the chances that life is out there?

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Voice Off Screen: This is very, very exciting, where can we find more about

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the recent results and any updates as we go forward?

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Dr. Paul Hertz: Well NASA makes all of it's discoveries about exoplanets available at our website

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nasa.gov/exoplanets