MESSENGER Buzzes Mercury

A QUICK ONE: Researchers report they have discovered the first planet around a young star still enshrouded by the disk of dust and gas from which it arose. Astronomers have long believed that a star's satellites coalesce from such protoplanetary disks, which solar wind and radiation eventually scour away, but they aren't sure of details such as how quickly a planet can emerge from the haze. The newly spotted planet (shown in this impressionistic artist's conception) circles its parent star, TW Hydrae, once every 3.56 days, just inside the star's disk, according to a report in this week's Nature. Researchers estimate that the TW Hydrae system is eight million to 10 million years old, meaning planet formation can occur within that time frame.