Unidentified Object

A small unidentified object whipped past Earth just outside the orbit of the Moon on May 21. It had been discovered on May 16.

Astronomers have determined the object is only a few meters long, is metallic on the exterior, and orbits the Sun in the same orbit Earth does. They speculate, therefore, that it's the upper stage of a rocket that launched an interplanetary probe on its way sometime in the past few decades. An enterprising grad student might come up with a pretty good paper if he or she could work out exactly which part of which rocket from which mission this object might be.

The object is also a reminder that although space junk may only be a real problem in Earth orbit, we have stuff scattered across the Solar System.