Washington, June 25 : After recently discovering three super-Earths, astronomers have said that it's just a matter of time before they find a planet identical to ours, or in other words, Earth's 'twin', which might be hiding somewhere in the Milky Way galaxy.
According to a report in Space.com, the three super-Earths are worlds more massive than ours, but small enough to most likely be rocky - orbiting a single star.
"Being able to find three Earth-mass planets around a single star really makes the point that not only may many stars have one Earth, but they may very well have a couple of Earths," said Alan Boss, a planet formation theorist at the Carnegie Institution of Washington in Washington, D.C.
Since the early 1990s, when the first planets outside of our solar system were detected orbiting the pulsar PSR 1257, astronomers have identified nearly 300 such worlds.
However, most of them are gas giants called hot Jupiters that orbit close to their stars because, simply, they are easier to find.
"So far we've found Jupiters and Saturns, and now our technology is becoming good enough to detect planets smaller, more like the size of Uranus and Neptune, and even smaller," said Geoff Marcy of the University of California, Berkeley.
Marcy, Boss and other scientists are optimistic that within the next five or so years headlines will be splashed with news of a near twin of Earth in another star system.
"What is amazing to me is that for thousands of years humans have gazed at the stars, wondering if there might be another Earth out there somewhere," Boss told SPACE.com. "Now we know enough to say that Earth-like planets are indeed orbiting many of those stars, unseen perhaps, but there nevertheless," he added.
The ultimate goal of planet-hunting projects is to find Earth twins.
"We are looking for twins of the Earth, analogs that walk and talk and smell like our own Earth," said Marcy, who is currently looking for super-Earths using the W.M. Keck Observatory in Hawaii.
Such a twin would be rocky, with a similar chemical composition to Earth, and would orbit within the habitable zone of its star.
"I suspect there are Earth-like planets with lakes and rivers and waterfalls and deep glacial gorges and that are spectacularly beautiful," said Marcy.