Earth-like Planet Discovered

The scientists have discovered for the first time a planet that is much like Earth. NASA's Kepler spacecraft first discovered this planet, named Kepler Kepler-22b, two years ago. This planet  joins a list of more than 500 planets found to orbit stars beyond our solar system.

The planet lies in the habitable zone of a solar system at whose center is a star only a little smaller and fainter than Earth's sun. The planet lays in a region neither too hot nor too cold - probably 72 degrees - for an atmosphere that could support some form of life.

Kepler-22b is 2.4 times Earth's size, although its mass is still unknown, said William Borucki, the leader of the Kepler science team. Kepler 22b circles its sun every 290 days, compared with Earth's year of 365 days.

This distant planet lies about 600 light-years away. A light year is the distance light travels in a year, about 6 trillion miles (10 trillion km). 

The Kepler telescope, which was launched three years ago, is staring at about 150,000 stars in the constellations Cygnus and Lyra.

"We are homing in on the true Earth-sized, habitable planets," said San Jose State University astronomer Natalie Batalha, deputy science team lead for NASA's Kepler Space Telescope that discovered the star.