International Space Station (ISS) crew member Canadian astronaut Chris Hadfield (L)plays chess with US astronaut Thomas Marshburn at Baikonur cosmodrome Dec 13, 2012. Hadfield and Marshburn, with crewmate Russian cosmonaut Roman Romanenko, are scheduled to fly to the International Space Station on Dec 19. [Photo/Agencies]

A large cloud of gas that has spawned dense internal knots which gravitationally collapsed to form stars is seen in this NASA handout image from the Hubble Space Telescope released Dec 13, 2012. Many young stars are visible in this image, along with what is left of the initial gas cloud. Some stars were so massive they have already evolved and exploded in a supernova.[Photo/Agencies]