Astronomers have, for the first time, observed the very beginning of planet formation around a star beyond our Solar System.

Sirius is bright enough to dominate the night sky after sunset particularly if there are no planets around. It’s very bright because: Sirius is a big blue-white star 25 times the mass of our Sun.

Only a handful of star systems have more than a single planet. With eight worlds, our solar system has long taken the prize for the biggest lineup. But no longer. Our corner of the galaxy now ...

A star celled HD 10180 may have even more planets than the sun, which would make the planetary system the most populated known. An artist's conception of the planetary system around HD 10180.

This star, known as HD 110067, may have even more planets. The six found so far are roughly two to three times the size of Earth, but with densities closer to the gas giants in our own solar system .

Astronomers have discovered six planets orbiting a bright star in perfect resonance. The star system, 100 light-years from Earth, was described on Wednesday in a paper published in the journal Nature.

Star systems come in all shapes and sizes. Some have lots of planets, some have larger planets and others have no planets at all. But a particularly unusual system about 150 light-years from our ...

The planets in our system are far more spread out, however. Neptune is, at its closest, 2.8 billion miles from the sun. The most distant gas giant in the Kepler 90 system is 93 million miles from ...