Download Hello, Universe? Anyone Home?

Hello, Universe? Anyone Home?
WASHINGTON, D.C. (Achieve3000, November 3, 2010)
For thousands of years, people have asked the timeless question: Are we alone in the
universe? Now, scientists are inching closer to an answer. For the first time, scientists
say they have spotted an Earth-like planet that fits into what is sometimes called a
"Goldilocks zone": a region of space that's not too hot and not too cold. It's juuuust right
to support life.
The new exoplanet is named Gliese 581g. It was discovered by astronomers R. Paul
Butler of the Carnegie Institution of Washington and Steven Vogt of the University of
California at Santa Cruz. Butler and Vogt found the planet circling a dwarf star called
Gliese 581, which is about one-third the strength of our sun. Using ground-based
telescopes, the two scientists tracked the star's precise movements over 11 years and
watched for wobbles that indicate planets are circling it.
Gliese 581g is located about 120 trillion miles away from Earth, so we won't be taking a
close look anytime soon. Still, in the scheme of the vast universe, said Vogt, "the planet
is "right in our face, right next door to us." In fact, if you were standing on Gliese 581g,
you could easily see our solar system's sun.
So far, astronomers have learned that the new planet is about three times the mass of
Earth and is slightly larger in width. Gliese 581g is also much closer to its sun than
Earth is to ours. The exoplanet is about 14 million miles from its sun. It completes a full
orbit in only 37 days. Earth, on the other hand, is 93 million miles away from our sun
and completes a full orbit in 365 days.
Based on Gliese 581g's location from its sun—it's not too far away nor too close—
scientists suspect that it could contain liquid water. This leads some astronomers to
suggest that it might also support life. This doesn't mean Gliese 581g is home to E.T.like creatures, or even humans and animals. However, even a simple single-cell
bacteria or the equivalent of shower mold would shake perceptions about the
uniqueness of life on Earth.
Previously, astronomers have proclaimed that planets outside our solar system were
habitable, only to have them turn out not to be conducive to life. But Gliese 581g is
unlike any of the nearly 500 exoplanets astronomers have found outside our solar
system. This is due to its location inside a Goldilocks zone, or "habitable zone," of
space. Not only is Gliese 581g not too hot and not too cold to support life, but it is
neither too big nor too small for suitable surface, gravity, and atmosphere conditions.
This makes it a promising candidate for habitability.
"This really is the first Goldilocks planet," said Butler.
For now, it's unclear whether water actually exists on Gliese 581g, or if the planet is
actually habitable. Astronomers have determined that temperatures on Gliese 581g can
reach a fiery 160 degrees Fahrenheit or an icy 25 degrees below zero. And because the
planet doesn't rotate much, one side of the planet is almost always bright, while the
other is dark. Still, on some parts of the planet, Vogt said, it would be "shirt-sleeve
weather."
The recent discovery of Gliese 581g hints to scientists that planets like Earth are
probably not that rare. Butler and Vogt estimate that there are 200 billion stars in the
universe. According to their calculations, as many as 1 out of 5 to 10 stars could have
planets that are Earth-sized and located in the habitable zone. That would mean 40
billion planets would have the potential for life. Some astronomers, however, caution
that this figure is too speculative to prove.
Although Gliese 581g's ability to sustain life is currently open to speculation, scientists
will have ample time to continue their research. Astronomers predict the planet's sun will
live on for billions of years, much longer than our own sun. According to Butler and
Vogt, that just increases the likelihood of life developing on the planet.
"It's pretty hard to stop life once you give it the right conditions," Vogt said.
The Associated Press contributed to this story.