Marc Kuchner: I don't know--when I was growing up, there was no such thing as planets around other
stars. If you were to talk about it at a scientific meeting, people would laugh at
you. Not that I was talking at scientific meetings when I was in high school, but
so I'm told.
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Jennifer Wiseman: Planets are very small compared to the stars that they orbit. They're also very dim.
Marc Kuchner: For example, the Earth is ten billion times fainter than the Sun--ten billion times fainter.
Jennifer Wiseman: It's kind of like trying to see a firefly next to a lighthouse. It gets lost in the glare.
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Marc Kuchner: The Hubble Space Telescope takes pictures of nearby stars and uses a
special tool called a coronagraph and the coronagraph blocks out the light from the star.
Aki Roberge: It's a fancy way of putting your thumb over the star,
basically, so you can see something faint that is right next to it.
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Jennifer Wiseman: We can also use Hubble and other telescopes to study regions
where we think planets might be forming.
Marc Kuchner: We see in images from Hubble, we see these rings of dust around nearby stars.
Aki Roberge: Well what I observe with Hubble are those disks.
Those disks of gas and dust around the young stars, in which we think the dust
grains are starting to clump together and build up into pebbles, rocks, asteroids, comets, Earths.
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Jennifer Wiseman: We're finding baby solar systems by using Hubble and other telescopes, including sort of
ground-based radio telescopes that can peer into these disks around stars and
see young planets or regions where young planetary systems are forming.
Aki Roberge: You know, the study of exoplanets is only a little over 15 years old.
Marc Kuchner: We've discovered more than 400 extrasolar planets now.
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Aki Roberge: You know, we're still just beginning to understand how the processes
that formed our own solar system, also formed these really diverse types of planets.
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I think the thing that excites me most is just the basic discovery of what exists. You know, what's out there.
Waterworlds, carbon planets? It sounds like science fiction, but not really. Not anymore.
Marc Kuchner: Why did life arise on Earth instead of somewhere else?
I mean if there's another planet that could have life on it, why aren't we there?
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