NASA Kepler mission brings sci-fi closer to reality

                 Americans who lament that this country can no longer seem to do anything great are overlooking technological wonders like NASA's Kepler mission and its search for habitable planets.
                 The Kepler space telescope, launched in March 2009, has led to abreak-through in planet hunting.  Aimed at a specific patch of the Milky Way, it already hsad identified 115 planets.  And, NASA announced last week, Kepler has found the two most Earth-like worlds yet ------ and the ones most capable of supporting life ------ in a five-planet system named Kepler-62 in the constellation Lyra.
                 The most promising planet for life is Kepler-62f, 40 percent larger than Earth but the right temperature and right in the middle of the habitable zone.  The other planet, Kepler-62e, is 60 percent larger than Earth and on the inner edge of the habitable zone.
                 NASA's William Borucki, head of the Kepler project, called 62f the best planet Kepler has yet found.  Alan Boss, a planetary expert and member of the team, said this discovery alone justified the approximately $600 million cost of the mission.
                 Kepler, like other NASA missions, has accelerated the speed of discovery.
                 For the sake of argument, let's say that astronomy ----- the systematic study of stars, planets and the universe ----- dates back to at least 3000 B.C., roughly when Stonehenge was built to track solstices and equinoxes.
                Forthose intervening thousands of years, astronomers vainly tried to locate a planet outside our solar system.  Although it seemed mathematically unlikely, the empirical evidence was alone in having planets, and that Earth alone was inhabited.
                That changed in 1992 with the discovery of the first "exoplanet," a planet outside our solar system.  Other discoveries followed, but these were of gas giants, larger than Jupiter, incapable of supporting life.
                The search was on for rocky planets, roughly the size of Earth, orbiting a star at a distance called the "Goldilocks zone," where it is not too hot, not too cold, with moderate temperatures hospitable to life.
                In the brief time we've known of exoplanets, astronomers have discovered almost 1,000 of them, along with more than 2,700 "candidate" bodies, potential planets for which proof is still lacking.
                The Kepler system is 1,200 light years away, or 708,000 trillion miles, dampening any immediate visitation prospects.  But the lesson of exoplanets is never to say never.