WASHINGTON — Astronomers say they have for the first time spotted a planet beyond our own in what is sometimes called the Goldilocks zone for life: Not too hot, not too cold. Juuuust right.
Not too far from its star, not too close. So it could contain liquid water. The planet itself is neither too big nor too small for the proper surface, gravity and atmosphere.
It's just right. Just like Earth.
"This really is the first Goldilocks planet," said co-discoverer R. Paul Butler of the Carnegie Institution of Washington.
The new planet sits smack in the middle of what astronomers refer to as the habitable zone, unlike any of the nearly 500 other planets astronomers have found outside our solar system. And it is in our galactic neighborhood, suggesting that plenty of Earth-like planets circle other stars.
Finding a planet that could potentially support life is a major step toward answering the timeless question: Are we alone?
Scientists have jumped the gun before on proclaiming that planets outside our solar system were habitable only to have them turn out to be not quite so conducive to life. But this one is so clearly in the right zone that five outside astronomers told the Associated Press it seems to be the real thing.
"This is the first one I'm truly excited about," said Penn State University's Jim Kasting. He said this planet is a "pretty prime candidate" for harboring life.
Life on other planets doesn't mean E.T. Even a simple single-cell bacteria or the equivalent of shower mold would shake perceptions about the uniqueness of life on Earth.
The astronomers' findings are being published in the Astrophysical Journal and were announced by the National Science Foundation on Wednesday.
The planet circles a star called Gliese 581. It's about 120 trillion miles away, so it would take several generations for a spaceship to get there. It may seem like a long distance, but in the scheme of the vast universe, this planet is "like right in our face, right next door to us," said co-discoverer Steven Vogt of the University of California at Santa Cruz.