Each year, the Earth passes through the debris of a comet called the Swift-Tuttle. This debris is pulled in by earth’s gravity & burns up in our atmosphere. The friction from the heat generated by these tiny dust particles, no larger than the head of a pin or grain of sand, reaching speeds of approximately 45km per second slam into the gases that make up the earth’s atmosphere, causing them to burn up and give off light. Some particles are large enough to leave a glowing trail of ferry like dust called a “contrail”, similar in appearance to a jet trail than can last for several minutes. These meteors are burning up in our atmosphere approximately 80-100km above our heads. For the most part, we are quite safe.
The dust particles come from the comet known as Swift-Tuttle, named after the first 2 people to discover it. The comet leaves a path of debris as it continues in its orbit around the sun every 120-125 years. When earth crosses this debris trail, gravity takes over and the show begins! It is estimated that this debris is about 1000 years old.
If you were to trace back the streak of light to its starting point, you will find it “radiates” from the constellation Perseus. This is known as the “radiant”. As the earth turns into the debris trail scooping up these dust particles, much the same as a car driving into a snow storm, you will see more shooting stars after midnight until early morning, as this is when we are ploughing head-on into the thick of the storm.
The rate of falling stars varies from year to year, with the best reported in 1972. There are many differences in meteor counts tallied by different people in different places. The best meteor shower I ever experienced had an amazing peak of approximately 200 for one or 2 brief hours!
For those wanting to delve a bit deeper, meteor counts are also performed using radio signals. When the particles burn up, they excite the hydrogen gas in the atmosphere which then releases a burst of radio waves at a known frequency. A search for more information on google will serve up an endless amount of interesting information for you to peruse through.
The Perseid Meteor Shower runs from about 2 weeks before and after the main peak dates of August 10-12. So keep your eyes on the skies for what is arguably The Greatest Show Off Earth!
Written by David Wilde