Although it may take millions of year for swirling clusters of interstellar gas and dust to become a mature planet, scientists have discovered that rapid changes can be observed even within a fraction of that time span.
Over the course of five months, the researchers observed that the infrared light from a disk of gas and dust around LRLL 31, a young star, tended to vary in unexpected ways. This suggests that another star — or perhaps a planet — is shoving the clump of planet-forming material around, which causes its thickness to vary as it spins around the star
More: http://www.space.com/scienceastronomy/090923-planet-clump.html (http://www.space.com/scienceastronomy/090923-planet-clump.html)