One of the most dangerous asteroids on record zipped close by Earth last month.
It made headlines on Thursday, when reports said that there's a chance it could strike our planet in less than 20 years. Such a collision could unleash a force as powerful as a couple of thousand atomic bombs.
But NASA was quick to calm nerves and point out some very good news. The most dangerous known asteroids don't really pose much of a threat. And there are very few of them.FULL STORY