Saturday, August 22, 2015

The Perseids

The Perseids are meteor showers observed in mid-August. Meteors or shooting stars are cosmic debris entering Earth's atmosphere at high velocity leaving a trail of burning gases observable in the night sky.
There was a star riding through clouds one night, & I said to the star, 'Consume me'.
Virginia Woolf, The Waves
Perseid meteor shower.
NASA/Bill Ingalls, Aug. 13, 2015

The Perseids are named after the constellation Perseus which is the area in space where the Perseid meteor shower emanates from, also called the Radiant. The word Perseids is derived from the Greek Perseides (Περσείδες) referring to those born of Perseus. In Greek mythology, Perseus is the son of the Zeus (god of the sky).

The Perseids occur as Earth's orbit intersects a band of debris left behind by comet Swift-Tuttle.

Sand-sized debris shed from the comet collides with Earth's atmosphere at speeds on the order of 130,000 miles an hour. The swift decrease in velocity, some 130,000 miles per hour of kinetic energy, transfers to the air molecules on impact causing the molecules to lose electrons.

The particles vaporize in streaks of light. The glowing streak is ionized air.
My dad took me out to see a meteor shower when I was a little kid, and it was scary for me because he woke me up in the middle of the night. My heart was beating; I didn't know what he wanted to do. He wouldn't tell me, and he put me in the car and we went off, and I saw all these people lying on blankets, looking up at the sky.
Steven Spielberg