Extrasolar planets - exoplanets - orbit a star other than the Sun. They are too faint to be seen directly with existing instrumenets, so indirect methods of detection are necessary. The first exoplanet was only discovered in 1992. It orbits a pulsar.
There are three methods for discovering exoplanets:
1. The radial velocity method - looks for a cyclical Doppler shift in the light from a star.
2. The transit method - looks for dips in the brightness of a star as the planet crosses the face of the star.
3. Astrometry - accurately measures the wobble of a star as a planet orbits.
Planet finding spacecraft such as COROT and Kepler use the transit method and to date 786 planets are known.
You can download the free exoplanet app and follow the discoveries. Maybe life is out there waiting for us... THIS IS AN EXCITING TIME indeed.
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