Noted physicist Stephen Hawking (center) returns to the Kennedy Space Center Shuttle Landing Facility after a zero gravity flight. At far left is Peter Diamandis, founder of the Zero Gravity Corp. that provided the flight aboard its modified Boeing 727. Hawking suffers from amyotrophic lateral sclerosis (also known as Lou Gehrig's disease). At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett