How close did asteroid 2005 YU55 get to Earth? Not close enough to endanger our civilization, but close enough to take some fun videos. Like this short film of its trajectory recorded by NASA Swift's satellite.
Swift's Ultraviolet/Optical Telescope started to track the asteroid just right after its closest approach to Earth:
Six hours later, around 3 a.m. EST on November 9, Swift began an exposure that captured the asteroid sweeping through the Great Square of the constellation Pegasus. The 11th-magnitude rock was then 333,000 miles away and moving at 24,300 mph, about an hour after its closest approach to the moon.
2005 YU55 is classified as a potentially hazardous space object. The real danger, however, will not come until the next century. NASA put the Swift's scientists on the case, even while the spaceship's main function is not to track asteroids or comets but to analyse gamma-ray bursts. Still, the Swift team have helped understand YU55's composition by analysing how its surface reflects light. This way, experts can evaluate if the reflection of sunlight as heat can produce enough force to modify the supercarrier-sized rock's trajectory in the distant future, thus increasing the possibility of a fatal encounter with our home planet. [NASA]