The unequivocal signature of water vapor has been found on a
planet beyond our solar system.
Using NASA's Spitzer Space Telescope,
the steamy signature of water vapor in the light coming from a large
exoplanet circling around a star about 63 light-years from Earth.
Though it's not the first sign of water vapor around this planet, it's
the strongest evidence yet.
The planet, HD 189733b, is what's called a "Hot Jupiter" — a boiling,
gigantic gas planet more akin to our own Jupiter or Saturn than to a
terrestrial planet like Earth. It's not a good candidate itself for alien
life, but the successful detection of water vapor here, in the
location and quantities that theorists predicted, bodes well for further
studies of more promising locales for extraterrestrial life.
"It means we're starting to understand these objects a
little bit better than we did when we first started," astrophysicist Adam
Burrows of Princeton University told Wired.com. "It’s a trial run for the
much more detailed investigations that will be possible in the years to come as
we take this stepping stone from giant planets to terrestrial planets."
Though water vapor is thought to be fairly common on planets — even
our own Jupiter has it — the discovery of its presence on another world
is significant and points the way toward future discoveries, scientists
say. Yesterday scientists announced that the Hubble Space Telescope
had found carbon dioxide, which under the right circumstances could be
connected to life, on the same planet. The presence of methane has also