Are other worlds like ours out there? It is this age-old question that NASA's planet-hunting telescope, Kepler, which rocketed into space Friday night on a historic voyage to track down other Earths in a faraway patch of the Milky Way galaxy, seeks to answer. The Kepler space telescope launched by NASA to search for Earth-like planets in the Milky Way galaxy has reached the orbit, the US space agency said “It was just magnificent. It looked like a star was being formed in the sky,” said Bill Borucki, Kepler's principal scientist. “Everybody was delighted, everybody was screaming, ‘Go Kepler!”' Kepler's mission will last at least 3 years and cost $600 million. The goal is to find, if they exist, Earth-like planets circling stars in the so-called habitable zone orbits where liquid water could be present on the surface of the planets. That would mean there are lots of places out there for life to evolve, Borucki said. On the other hand, “if we don't find any, it really means Earths are very rare, we might be the only extant life and, in fact, that will be the end of ‘Star Trek.'î Once it's settled into an Earth-trailing orbit around the sun, Kepler will stare nonstop at 100,000 stars near the Cygnus and Lyra constellations, between 600 and 3,000 light years away. The telescope will watch for any dimming, or winks, in the stellar brightness that might be caused by orbiting planets. Astronomers already have found more than 300 planets orbiting other stars, but they're largely inhospitable gas giants like Jupiter. Kepler will be looking for smaller rocky planets akin to Earth. NASA was counting on a successful launch to offset the loss last week of the space agency's Orbiting Carbon Observatory. That environmental satellite ended up crashing into the Antarctic because of rocket failure. It was a different type of rocket than the one used for Kepler. Ever since astronomers first turned their telescopes to the sky, humans have been searching for other planets. But the small size of planets compared to stars has complicated the task. Only eight planets have been found in our solar system -- Pluto is now considered a mere planetoid.
