The 460-foot wide asteroid 2011 AG5 could be on a collision course with our planet. But the odds are very small, say scientists.
Apophis asteroid: Russian scientists are warning that a rock the size of two football fields is poised to strike our planet in 2036. But NASA says the odds are just one in a quarter million.
02/07/2011 12:56 pm
The preliminary concept idea was proposed at a symposium on solar sails, which are spacecraft powered by sunlight pushing against a sail.
12/22/2010 04:10 pm