NASA’s Hubble Space Telescope has gotten a rare peek at the aftermath of two cosmic collisions — and helped scientists solve a decades-old mystery. Many years ago, scientists saw a dense, bright spot near a young star and thought it could be a planet. After finding a second one, they realized it was actually the dusty debris from two cosmic crashes. Massive space rocks had slammed together to create clouds of dust that were thick enough to masquerade as planets. The new study was published Thursday in the journal Science.