Earth-size planets ‘prevalent’ in our Milky Way galaxy

Earth-size planets ‘prevalent’ in our Milky Way galaxyWashington, Oct 29 : A new study funded by NASA and the University of California has revealed that nearly one in four stars similar to the Sun may host planets as small as Earth.

The study is the most extensive and sensitive planetary census of its kind. Astronomers used the W. M. Keck Observatory in Hawaii for five years to search 166 Sun-like stars near our solar system for planets of various sizes, ranging from three to 1,000 times the mass of Earth. All of the planets in the study orbit close to their stars.

The results show more small planets than large ones, indicating small planets are more prevalent in our Milky Way galaxy.

"We studied planets of many masses -- like counting boulders, rocks and pebbles in a canyon -- and found more rocks than boulders, and more pebbles than rocks. Our ground-based technology can't see the grains of sand, the Earth-size planets, but we can estimate their numbers," said Andrew Howard of the University of California, Berkeley, lead author of the new study.

"Earth-size planets in our galaxy are like grains of sand sprinkled on a beach -- they are everywhere."

The research provides a tantalizing clue that potentially habitable planets could also be common.

These hypothesized Earth-size worlds would orbit farther away from their stars, where conditions could be favorable for life.

NASA's Kepler spacecraft is also surveyingSun-like stars for planets and is expected to find the first true Earth-like planets in the next few years.

The study appears in the Oct. 29 issue of the journal Science. (ANI)