In 1995 the first convincing evidence was obtained for a planet around another star. Now, over 60 exoplanetary systems are known, and the number is growing steadily month by month. All of these exosystems have been discovered by detecting the orbital motion of the star induced by its planet(s) - the planets cannot yet be seen directly because they are much fainter than their star and have too small an angular separation from it.


With present technology, only giant planets like Jupiter and Saturn in our Solar System, can be detected - any Earth-mass planets would have too small an effect on their star's motion.