Launched in August 2003, Spitzer surveys its galactic surroundings using instruments that detect infrared radiation. The telescope recently observed a star located some 420 light-years away known as CoKu Tau 4 and found a clearing in the dusty disk surrounding it, which could be caused by a planet gathering material as it forms--like a broom sweeping across a dirty floor. This potential planet is less than a million years old--the age of CoKu Tau 4--making it a mere infant compared to our own 4.5-billion-year-old planet.
Spitzer also spied two of the faintest planet-forming disks ever seen in a stellar nursery, 13,700 light-years from Earth. Dubbed RCW 49, the region encompasses some 300 newborn stars. "Preliminary data suggest that all 300 or more stars harbor disks," remarks team member Ed Churchwell of the University of Wisconsin in Madison, "but so far we¿ve only looked closely at two." The additional details that Spitzer can offer about planet-forming disks should provide scientists with a better understanding of how solar systems like ours evolve.