How fast does gravity travel? When will the sun go nova? Who invented the light year? Will we ever travel to the stars? These are just some of the unusual and popular questions NASA astronomer Sten Odenwald answers in 'Back to the Astronomy Cafe', based on his award-winning website "for the astronomically disadvantaged." Since his acclaimed earlier book 'The Astronomy Cafe' published in 1998, the space community has been turned on its head with entirely...