Topic: Jim Green
Astronomers estimate that an asteroid the size of 2012 DA14, which came within a cosmic hair's breadth of our planet on Friday, strikes the Earth once every 1,200 years or so.
Even as the Curiosity Mars rover was still testing its equipment in preparation for its surface mission, NASA has unveiled plans for another unmanned mission to Mars. Is the agency playing favorites?
The probes' new names were offered by fourth grade students in Bozeman, Mont., who were chosen as the winners of NASA's naming contest.