10. Peak of the Perseids
The annual Perseid meteor shower reached its peak mid-August, with a moonless sky providing near-perfect observing conditions. (See pictures of Perseids past.)
The Perseids appear like clockwork each year when Earth passes through a giant cloud of debris left in the wake of comet Swift-Tuttle. Hitting the atmosphere at speeds of almost 100,000 miles (160,000 kilometers) an hour, the meteors burn up and produce streaks of light that each last just a fraction of a second.
Full story: "Meteor Shower Peaks Tonight—How to See Perseids"
Best Space Discoveries of 2010: Nat Geo News's Most Popular
Bright meteors and mind-bending theories about the universe were among National Geographic News's most viewed space stories of 2010.