Perseid Meteor Shower: What Causes the Annual Sky Spectacle

What's causing those bright flashes of light at meteor shower's peak.

— -- When the Perseid meteor shower reaches its peak action early Thursday morning, as many as 100 meteors per hour will be visible streaking across the sky.

The meteors from this year's show are sure to create another dazzling spectacle that begins each year when Earth passes through a cloud of the Swift-Tuttle Comet’s debris, according to NASA, causing small bits of comet dust to enter our atmosphere at 37 miles per second.