ROUGH CUT - NO REPORTER NARRATION<br /> <br />STORY: One out of every five sun-like stars in the Milky Way galaxy has a planet about the size of Earth that is properly positioned for water, a key ingredient for life, a study released on Monday (November 4) showed.<br /> <br />The analysis, based on three years of data collected by NASA's now-idled Kepler space telescope, indicates the galaxy is home to 10 billion potentially habitable worlds.<br /> <br />The number grows exponentially if the headcount also includes planets circling cooler red dwarf stars, the most common type of star in the galaxy.<br /> <br />Study leader Erik Petigura, an astronomy graduate student at the University of California at Berkeley, said during a conference call with reporters, that planets seemed to be the rule and not the exception.<br /> <br />Petigura wrote his own software program to analyze Kepler's results and found 10 planets one- to two times the diameter of Earth circling parent stars at the right distances for liquid surface
