The Great Celestial Sideshow

The date was November 30, 1954 and in a house across from the Comet movie theater in Sylacauga, Alabama, Mrs. Hodges decided to take a nap. She chose to recline on the living room couch, hardly an unusual choice for a nap. It was, however, a bad choice. Mrs. Hodges had probably drifted of into blissful tranquillity, perhaps assuring herself that the heavens would not descend if she sneaked in a nap. But the universe seems to know about a famous law named after an otherwise obscure person named Murphy because a piece of the heavens promptly descended, three pounds of it to be exact, and crashed through the Hodge's roof, through the living room ceiling, then bounced off a console radio and took up residence on Mrs. Hodge's left thigh. Fortunately Mrs. Hodges was not critically hurt; she had a severe bruise, but lived to tell about the space rock that came to call.

Many of us have seen a bright flash streak across the night sky. As children, we were told to "make a wish upon a falling star." But they are not stars at all, but meteors, the debris of the solar system.

A meteor is a solid icy or rocky body, heated to incandescence by its passage through Earth's upper atmosphere. Meteors heat up the same way the space shuttle or other spacecraft do when they re-enter the Earth. The meteors attain entry speeds of 20 or 30 kilometers per second, and get hot enough to begin to vaporize. The trail of evaporating gas emits light, making the glow that we see.

The Earth may be hit by 100 million meteors every day, about one hundred tons of them. Of these, only about 500 make it through the atmosphere each year, and of these, only about 10 are found. Most meteors are tiny grains of material, rarely larger than a marble, and burn up completely in the atmosphere. The majority are too faint even to be seen.

At certain times of the year, we have what is called meteor showers, where 20 to 60 or more meteors may be seen per hour. The best known meteor shower is the Persied shower which peaks August 12th and 13th every year. Meteor showers are associated with the orbits of comets, and when the Earth passes through the comets orbit on its way around the Sun, some of the debris falls to Earth, and we have a shower.

While meteor showers are associated with comets, meteorites are not. Occasionally a larger chunk of debris makes it through the atmosphere and lands on Earth. These are called meteorites. Meteorites are far more dense than their comet related cousins and it is believed that most of them originate from the asteroid belt, a region between the orbits of Mars and Jupiter. These chunks may have been knocked out of their orbits by collisions with other asteroids.

Meteorites are very difficult to find; most of them look like ordinary Earth rocks. The Antarctic is the best place to find meteorites because they are easier to spot on the permanently snow covered ground. While we may never actually find a meteorite, we can content ourselves with a meteor shower.

If the weather cooperates, we can watch the Persied meteor shower August 12th and 13th. The moon will be in the sky to outshine some of the meteors, but you should still see a worthwhile show.

To view the Persieds, go out after dark on the nights of August 12th or 13th. Preferably use a lounge chair since you will be looking up. Look high in the northeast sky in the direction of the constellation, Perseus, and if you just relax and let your eyes wander in that area, you will stand the best chance for seeing the most meteors. The Persieds peak at about sixty meteors per hour. You may even see some break up and become two streaks. Ideal conditions are away from city lights, but brighter meteors can still be seen from neighborhood areas. The later you stay out the better your chances are. After midnight, the Earth turns into the direction of the shower, and just as your front gets more wet when you are running in the rain, you will see more meteors from the leading edge of the earth.

For the past several years, astronomers have been predicting that the Persied shower will turn into a meteor storm, where hundreds of meteors can be seen per hour. So far, we have not seen a storm, but who knows, perhaps we will get lucky this year.

Periodic meteor showers worth watching occur about six times a year. Samples of meteorites can be found at most museums. There are even places where you can buy your very own meteorite. But if you're hoping to get lucky like Mrs. Hodges, forget it. Odds against your getting hit by a meteorite are about ten trillion to one, truly astronomical proportions.