NASA had launched another stunning space telescope: The Kepler Telescope is on the mission to survey more than 100,000 sun-like stars in  NASA’s quest to find Earth-like planets in our Milky Way galaxy. 

The Kepler mission is expected to last for about three years and will include the survey of more than 100,000 sun-like stars in the Cygnus-Lyra region of our Milky Way galaxy. NASA hopes the telescope will identify hundreds of planets that are at least the size of Earth orbiting distance stars which are much like our own sun in energy output, luminosity and mass. The telescope will focus on the potentially habitable zone within their space and "could find dozens of worlds like ours." However, NASA also mentioned that Kepler may not find any such "Earths" -- especially if they are rare.

The vast majority of the approximately 300 planets known to orbit other stars are much larger than Earth and not one is believed to be habitable. The majority that we've been able to detect so far are more like extremely large Jupiters -- gas giants.

The Kepler telescope is specially designed to detect the periodic dimming of stars caused by transiting planets, NASA explained. Some star systems are oriented in such a way that their planets cross in front of their stars as seen from our Earthly point of view. As the planets transit, they cause their star's light to slightly dim, or wink. “The telescope can register changes in brightness of only 20 parts per million,” NASA said. In late 2006, when NASA was able to detect Fomalhaut-b, the variation between the sun's brightness and the planet itself was that the planet was over 20 billion times less luminous.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., is responsible for the spacecraft and the Kepler mission development.  By Wolfgang Gruener.