How big can they get? What's the largest so far detected? Where does an 18 billion solar mass black hole hide? We've never seen them directly, yet we know they are there. Lurking within dense star clusters or wandering the dust lanes of the galaxy. Where they prey on stars. Or swallow planets whole....

Launched on Feb. 11, 2010, the Solar Dynamics Observatory, or SDO, is the most advanced spacecraft ever designed to study the sun. On June 5 2012, SDO collected images of the rarest predictable solar event--the transit of Venus across the face of the sun. This event happens in pairs eight years apa...

Twenty-seven years ago, Sally Ride became the first American woman in
space on Jun 18, 1983. She accomplished this historic milestone when
she flew aboard Space Shuttle Challenger as a mission specialist for
the six-day STS-7 mission. Ride, a southern California native, was also
a mission specia...