Astronomers Solve Mystery of Dusty Foot Trails Crossing Telescope Mirrors

(Written by Christine Pulliam, Smithsonian Astrophysical Observatory, for Science at the Smithsonian, a website featuring highlights of scientific research at the Smithsonian Institution. )

Accustomed to peering through the dust and debris of outer space, astronomers at the Smithsonian’s Whipple Observatory in southern Arizona were perplexed to find fresh deposits of dust and dirt upon the fragile mirrors of their telescopes. What type of creature is small, four-legged, and likes to leave its footprints on scientific instruments, they wondered?

The mystery visitor first appeared in 2008, wandering into a building that holds the MEarth project—eight robotic telescopes designed to search for distant planets. Over the months that followed, the stealthy critter returned, eventually marring the mirrors on five of the modest-sized telescopes. Even Neil deGrasse Tyson, host of the PBS television show NOVA ScienceNOW, commented on the telltale prints when he visited the observatory for an episode that aired during the summer.