The Perseids grace our skies when Earth plows into a stream of fragments—ranging in size from sand grains to boulders—left behind by a comet. These particles slam into the atmosphere at speeds of 100,000 miles (160,000 kilometers) per hour, causing the meteors to burn up in the upper atmosphere, which produces a momentary streak across the overhead skies known as a shooting star.

"As the Earth passes through the dust trail of comets, it encounters debris—some of which can be the size of grapefruit or larger—which [then] can cause fireballs," said Raminder Singh Samra, resident astronomer at the H.R. MacMillan Space Centre in Vancouver, British Columbia.

"The chances of seeing fireballs always increase when there is a strong meteor shower like