An asteroid the size of a large storage shed came within 4,100 miles of Earth this spring, making it the closest near miss ever recorded, U.S. astronomers said this week.

The 15- to 30-foot space rock, now called 2004 FU162, was spotted on March 31 by MIT's Lincoln Near Earth Asteroid Research project, or Linear, using telescopes in New Mexico. However, it was not initially submitted to a national astronomy organization for classification as a near-earth asteroid because the telescopes had managed to track the object for only 44 minutes, and because it was deemed too small to be a threat, said Linear team member Jenifer Evans.