Space Rocker

By AISHA LABI

"It's Done," the entry on Brian May's Web site proclaimed last month.

Nearly 37 years after beginning work on his dissertation in astronomy at London's Imperial College, the guitarist for Queen successfully defended his 48,000-word thesis, "Radial Velocities in the Zodiacal Dust Cloud," in a three-hour oral examination.

Mr. May's detour from academe began at...