O Brother, Where Art Thou?

That's Scott on the left.                                    NASA TV

The first ~ and, so far, only ~ set of identical-twin astronauts, Mark and Scott Kelly, could help scientists understand more about the effects of long-term space flight. In 2015, while Scott Kelly rockets up to the International Space Station for a one-year stint there, Mark Kelly will stay back on Earth, as the control. Both will be giving blood and saliva samples before, during, and after the trip, as well as having their bone mass measured, sleep patterns analyzed, and more: http://www.newscientist.com/article/dn23999-astronaut-twins-could-reveal-genetics-of-space-health.html#.UgF_D1Mtfgc