Twenty years ago, the only planets that scientists could say existed for sure were the nine -- now eight -- in Earth's own solar system. (Pluto used to be in the club, but was downgraded to a puny ice rock a few years back.)

The best science could do was assume that millions of planets circled other suns, but because of the vast distances and the relatively small size of planets compared to the stars they orbit, they had no way of directly observing them or verifying their existence.

Prior to 1995, the idea that "extra-solar planets" existed was more a matter of faith and statistical probability than tangible science. Then, 13 years ago, scientists detected a gaseous planet half the size of Jupiter orbiting Pegasi 51. They could "see" it indirectly, thanks to the gravitational tug the planet exerted on its host star. Since then, 270 "exoplanets" have been detected using the so-called "wobble method."

Recently, scientists have developed new methods for locating Earth-sized planets using a system of powerful robotic cameras that added 10 more to the list.

Last Monday, a team of European astronomers using an even more advanced detection method said that about a third of the Sun-like stars in the galaxy have modest-sized planets. They unveiled data about 45 newly discovered worlds, including a triple-planet system of "super-Earths" circling a star 42 light-years away.

As the methods for detecting extra-solar planets get more sophisticated, the chance of finding one that could be hospitable to life doesn't seem like a shot in the dark anymore. Rather than the stuff of science fiction, new worlds to intrigue the scientific mind will soon be as exciting as they are commonplace.