I started watching meteors in the summer of 1961. I gave them little thought other than that they were streaks across the sky. People called them "shooting stars." I cringe when I hear that. It is an arduous task trying to explain to someone who knows nothing about astronomy that meteors have nothing to do with the stars. By 1962, I knew enough to know I was watching the Perseid meteor shower and that it peaked the night of August 11 and morning of August 12. The payoff came in 1964, in my cousin's backyard when I counted 351 meteors. They were falling like snowflakes in the east before dawn. Some were bright and left trails. Some exploded into pieces! Others were points of light, a sign they were coming straight at me. The finale came at dawn. It was daylight, and my cousin was yelling! I looked up to see a fireball, or bolide, the size of a half moon! It was a fitting climax to a night that turned into an orgasm of meteors!
A meteor shower is a phenomenon in which meteors emanate from a point in the sky called a radiant. Most meteors are no larger than grains of sand. They originate from streams of debris left by comets. Showers occur when Earth crosses these streams.
Meteors appear to radiate from a single point because they travel in parallel paths. It is a matter of perspective. Meteor showers are named for the constellations behind their radiants. Radiants cross the sky as the earth rotates. More Perseids are seen toward morning because we meet them head-on.
Meteors heat up when they enter our atmosphere. They reach a temperature of 4000 degrees. Most are vaporized 50 miles up.
The International Astronomical Union defines a fireball as a meteor brighter than Venus. A bolide is a bright fireball.
8 meteor showers:
QUADRANTIDS - Peak January 3.
Only serious meteor buffs will be out on a cold night in January. And if the name of this shower sounds strange, it is because it is named after an extinct constellation. Its radiant is in the constellation Bootes. The meteroid stream is narrow, and high northern latitudes like Sweden offer the best observation. Quadrantids are faint.
LYRIDS - Peak April 21.
Associated with Comet Thatcher, the Lyrids were observed by the Chinese in 687 B.C. It is a modest shower with its radiant near Vega. The Lyrids flared up in 1982, producing 90 meteors an hour.
ETA AQUARIDS - Peak May 5.
These meteors are associated with Halley's Comet. The radiant is near the star Eta Aquarii. Some meteor showers get their names from stars. Australians have a better view since Aquarius is high in their sky. They see up to 40 an hour.
PERSEIDS - Peak August 11/12.
The Perseids is the best meteor shower because of its numbers and because of warm weather. It can be cloudy, however, and the moon can interfere. The action begins around midnight when the earth has turned in the right direction. The Perseids peak before dawn with their radiant high in the sky. A meteor is seen every minute, and they are fast! Trace them backward, and they originate from a point near Perseus' head. Counting meteors is a lazy man's sport. All you need is a lawn chair and some mosquito repellent. Look for dark skies in the open with few trees.
The Perseids are associated with Comet Swift-Tuttle. Debris stretches along its orbit. Swift-Tuttle returns every 130 years, last approaching in 1992. Perseids start on July 23 and continue through August 20. Pea-like bits enter Earth's atmosphere at 40 miles a second.
We do not see these bits. What we see is ionized air glowing around them. A meteor's direction matters, whether it is meeting us head-on or catching up with us from behind. The Perseids meet us head-on, which is why they are fast.
DRACONIDS - Peak October 8
These slow meteors from Comet Giacobini-Zinner were brilliant in 1948.
ORIONIDS - Peak October 20.
Yet another shower from the dust of Halley's Comet, the Orionids favor the Southern Hemisphere. Orionids are beautiful because they fall against the background of bright winter stars. The radiant is close to Betelgeuse.
LEONIDS - Peak November 17.
The Leonids are associated with Comet Temple-Tuttle. That this prolific shower peaks November 17, is a shame because of cold weather. The radiant is inside the sickle of Leo. The Leonids are known for meteor storms, outbursts of 1000 meteors an hour. The storm of 1833 was so intense that people thought it was the end of the world. Joseph Smith, the founder of Mormonism, thought it heralded the second coming of Christ.
GEMINIDS - Peak December 13.
Geminids are caused by an asteroid. They are slow moving and believed to be increasing. The radiant is near Castor. 50-70 meteors an hour are possible. Cold nights discourage.