many planets are there? So far we have identified a number of extrasolar planets, called exoplanets, planets beyond our solar system. The account of early June 2010 is 461 as per page exoplanet.eu web. But this has increased dramatically on June 14, when NASA announced the first results of the Kepler space telescope. They identified 706 new candidates. And that will include data from the first 43 days of observation. As you can see, this number is quite larger than all the planets that have been found over the past 15 years since the first was found in 1995.
Kepler telescope and observation area (field of view). Credit: NASA / JPL
The Kepler telescope is similar to the Hubble telescope, floating outside the Earth's atmosphere offers a splendid view to the stars. The advantage is that there are no clouds or bad weather or atmospheric disturbances. Exoplanet candidates detected by measuring the brightness of stars. If the light is changing periodically, possibly there are planets circling the star, taking some of the light reaching the telescope when passing in front of the star.
light curves of transit (transit light curves), when a planet passes in front of a star, the brightness (flux) decreases. Credit: NASA / Kepler Mission
The Kepler aims at all times to a region in the same constellation, Cygnus, Lyra, and has the ability to change their area of \u200b\u200bobservation. But there are many stars in that constellation to be busy for a long time.
The ultimate goal is to find habitable exoplanets. For that several conditions must be met. The star has to be similar to the Sun, the exoplanet of similar size to Earth and must be a planet-star distance similar to that between the Sun and Earth. Only then can we ensure that there is water, the basis of all life as we know it.
The Kepler telescope will be measuring at least 3 ½ years, if not more. Much time to find many more exoplanets. Perhaps some like Earth, and therefore with the potential to harbor life.
More information: NASA Kepler mission and site
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