New Planets.

The sun is the major "star" of our solar system, with nine orbiting planets. But in the universe the sun is just one average-sized star among billions.

Last August, astronomers (space scientists) announced the discovery of nine new exoplanets, planets outside our solar system that orbit their own sun-like stars.

The newly detected planets are the latest in a flurry of exoplanet discoveries--at least 50 have been found since 1995. "It's hard to keep track of them all," says University of Texas astronomer Bill Cochran.

The closest planet found is 10.5 light-years (62 trillion miles) away from Earth--to far to spy with a telescope. Instead, astronomers used the Doppler technique, which uses light waves to measure a star's "wobble."

A star wobbles on its axis when orbiting bodies like planets exert gravitational pull (force of attraction between bodies of matter). The gravity-induced wobble causes changes in the frequency (number of vibrations) of light waves that a star emits, alerting astronomers to the presence of other planets.

Stargazers have discovered 12 stars with orbiting planets. The discoveries may point to the existence of solar system much like our own. "We've yet to find planets capable of supporting life," says Cochran. "But if our sun isn't unique--why wouldn't another Earth exist?"