What must our ancestors have thought when they saw meteors light up the night sky? Was it terrifying or an event of wonder? Thankfully, we now know that this celestial cascade is a harmless annual event. The Perseid meteor shower thrills stargazers from mid-July to late August and is due to peak today. The Perseids are caused by Earth passing through debris left behind by the Comet Swift-Tuttle. When the cosmic debris hits our atmosphere, it disintegrates in a colorful, fiery light display. It's a good night to catch the Perseids if you can—the moon is projected to only be 10% illuminated, so the meteors should really stand out against the dark sky.