New Delhi: Astronomers have discovered an earth-like planet that could support the crucial conditions needed for life.
The new planet sits directly in the middle of what is referred to as the habitable or Goldilocks zone, unlike any of the nearly 500 other planets astronomers have found outside Earth's solar system.
This new planet is three times the mass of the earth and slightly larger in width.
Reportedly this planet orbits every 37 days and does not rotate much so one side of it is almost bright, the other dark.
Temperatures can be as hot as 71 degrees Celsius or as frigid as minus 4 degrees Celsius, but in between, in the land of constant sunrise, it would be "shirt-sleeve weather," according to co-discoverer Steven Vogt of the University of California at Santa Cruz.
The astronomers' findings are being published in Astrophysical Journal and were announced by the National Science Foundation on Wednesday.
But there remain many unanswered questions about the planet.
It is about three times the mass of Earth, slightly larger in width and much closer to its star, Gliese 581.
It's about 120 trillion miles (195 trillion kilometres) away, so it would take several generations for a spaceship to get there. It is so close to its version of the sun that it orbits every 37 days.
It is unknown whether water exists on the planet, and what kind of atmosphere it has.
"I mean if the atmosphere is pure ammonia it might be tough. If it's conventional gases like oxygen and carbon dioxide, that sort of thing, sure there is every bit of reason to think that life as we know it could exist there," Vogt said.
It may seem like a long distance, but in the scheme of the vast universe, this planet is extremely close.
"The truly exciting thing about this discovery is that the star is so nearby, and we found it relatively quickly in the scheme of things. So this suggests that potentially habitable planets are very, very common," Butler said.
Vogt and Butler used ground-based telescopes to track the star's precise movements over 11 years and watch for wobbles that indicate planets are circling it.
The newly discovered planet is actually the sixth found circling Gliese 581.
With the star designated "a," its sixth planet is called Gliese 581g.
The star Gliese 581 is a dwarf, about one-third the strength of Earth's sun.
Finding a planet that could potentially support life could be a major step toward answering one of science's ultimate questions.
"The real question has always been are we alone or not in this universe," Vogt said on Wednesday. "If we do find places where we know life exists, it will tell us a lot more about how we fit in the hierarchy of life in the universe."
Scientists have jumped the gun before on proclaiming that planets outside Earth's solar system were habitable only to have them turn out to be not quite so conducive to life.
However, even a simple single-cell bacteria or the equivalent of shower mould would shake perceptions about the uniqueness of life on Earth.