Planet Formation

For years, the dominant theory of how planets form has been that a disk of gas and dust forms around a young star-- a dynamic disk, animated by swirling streams of matter. Clumps of matter begin to form, and grow. Some clumps grow larger than others. Sometimes clumps collide and merge. Eventually, the clumps can grow large enough that they sweep up all the matter around them as they orbit their star, creating gaps in the disk. Clumps can become planets.

Astronomers seem to have found a disk with a gap in it around a young star 350 light years away. The star is similar to the Sun, except that it's only about 7 million years old. They are now looking for an object within the gap to clinch the deal. If they find such an object, it will argue that planets can begin to form quite soon after the parent star ignites.