A Grand Summer Meteor Shower

A Grand Summer Meteor Shower

Streaks of light will brighten the night sky around mid-august in North America, as one of the best and most dependable meteor showers reaches its peak. The Perseid meteors, so called because they appear to radiate from a point in the constellation Perseus, are at their peak in mid-august and viewing is especially good when the Moon’s phase is New or almost New.

It’s best to watch the Perseids (or any other meteor shower, for that matter) from a location far from interfering city lights. And be sure to arrive at your viewing site well ahead of time because it can take your eyes half an hour to fully adjust to the darkness. If you have sufficiently dark skies, you can expect to see about sixty meteors per hour after midnight, although they won’t necessarily be evenly distributed.

Comet Brorsen-Metcalf Displays a Multi-Component Tail. Photo: Public domain

The Perseids hold a special place in the history of meteor shower observations. In 1866 astronomers determined that the Perseids share their orbit with Comet 1862 III, which completes one pass around the Sun approximately every 120 years. This discovery led astronomers to conclude that the Perseid meteors are in fact tiny dust particles that have broken free of the comet, a “dirty snowball” of frozen gas and dust that leaves a trail of debris in its wake.

As Earth intersects the comet’s orbit each summer it is bombarded by countless comet particles, most of which are no larger than a grain of sand. When they strike Earth’s atmosphere at the astounding speed of 37 miles per second – nearly 135,000 miles per hour – the cometary particles vaporize, producing a brilliant streak of light across the night sky.