Rocky planets, resembling Earth could be found around most sun like stars in our galaxy, a new research suggests, raising scientists’ hopes that they will someday find extra-terrestrial or at least primitive life beyond our solar system.

Using, NASA’s Spitzer Telescope, Michael Meyer of the University of Arizona discovered that at least 20 percent and possibly up to 60 percent of stars similar to the Sun could potentially have rocky planets in orbit around them.

Meyer looked at six groups of stars with masses comparable to the Sun, with the youngest being between 10 and 30 million years old and the oldest between a billion and three billion years old.

He and his colleagues detected discs of cosmic dust around stars in some of the youngest groups surveyed. They believe the dust is a by-product of rocky debris colliding and merging to form planets.

It is already thought that giant clouds of dust that gather in a disc around stars form terrestrial planets. If these clouds become dense enough, they collapse in on themselves by gravity to form big balls of rock.

“From those observations of dust, we infer the presence of colliding larger rocky bodies, not unlike asteroids and other things in our solar system that we know bang together and generate dust. By tracing that dust, we trace these dynamical processes that we think led to the formation of the terrestrial planets in our solar system,” Meyer said when presenting his findings Monday at the annual meeting of the American Association for the Advancement of Science. His findings also appear in the February edition of the Astrophysical Journal Letters.

Meyer added that more studies were needed to determine which of these stars possibly hold extraterrestrial life.

“What we need is much more data, more missions, more observations to inform what we hope will become a predicted theory of planet formation that we can use to guide our search for life in the universe," he said.

However, he said the theory about the existence of only nine planets in our Solar System was no longer valid, as “there are hundreds if not thousands of planets” in it.

The European Space Administration’s Darwin mission is currently conducting a similar research for extraterrestrial life. This mission is aimed at discovering extra solar planets and whether their atmospheres can sustain life.
 
However, NASA’s Kepler mission, due to be launched next year, is expected to reveal more clues about these distant undiscovered worlds. Kepler is designed to survey our region of the Milky Way galaxy to detect and characterize hundreds of Earth-size and smaller planets that are close enough to their stars to support possible life.