Randi has pursued "psychic" spoonbenders, exposed the dirty tricks of faith healers, investigated homeopathic water "with a memory," and generally been a thorn in the sides of those who try to pull the wool over the public's eyes in the name of the supernatural.
Dr. Phil Plait is a real live astronomer who earned his Ph.D. in 1994 from the University of Virginia. He currently works on a NASA-sponsored public outreach program for a satellite named GLAST (Gamma Ray Large Area Space Telescope). Phil runs the excellent BadAstronomy.com, and was author of the book of the same name. Phil is well known for debunking astrology and other pseudoscience such as Planet X, the Moon hoax conspiracy, and the face on Mars.