Does Earth belong to the first generation of habitable planets in the universe? One astrophysicist's work suggest it's possible, although we may never know for sure. It's a virtual certainty that comets have delivered the building blocks of life to Europa's hidden ocean, according to a new study. Observations by NASA's MAVEN Mars orbiter suggest that shooting stars lit up the Red Planet's skies after the close flyby of Comet Siding Spring this past October. Current page: 1