A significant number of both astronomy buffs and laypersons alike were baffled when, in 2006, Pluto’s status was downgraded to a “dwarf planet” after 75 years of planethood. Want to know why? Don’t miss your chance to meet the man behind the science this week, when Caltech University’s Dr. Mike Brown delivers his lecture How I Killed Pluto and Why It Had It Coming at the S.B. Museum of Natural History (2559 Puesta del Sol Rd.). Brown, a professor of planetary astronomy, will discuss his discovery of Eris-an even larger body in the outer solar system-which, in the end, caused astronomers to make the planet-altering decision to boot Pluto. The lecture takes place Saturday, November 14, at 3 p.m. Tickets are $10-$12. Call 682-4711.