Transcript:

The Perseid Meteor Shower(In Memory of Meteorologist Douglas Revelle)Here's a program from our archives.ambience: timelapse recordings of meteorites explodingLook up towards the constellation Perseus on a clear night this week, and you're likely to see a falling star. It's actually a particle of space dust, streaming down during the annual Perseid meteor shower. I'm Jim Metzner, and this is the Pulse of the Planet. We're listening to timelapse recordings of meteors exploding as they enter earth's atmosphere. According to Douglas Revelle, a scientist with Los Alamos National Laboratory, when debris from space enters the Earth's atmosphere in millions of tiny particles, it causes a meteor shower. Revelle: And you can see very bright streaks of light in the night sky in August because these particles are moving so fast and they collide with air molecules, and the air molecules then give that energy back as light that we can see on the ground.According to Dr. Revelle, the Perseid meteors are actually debris left behind by a comet orbiting the solar system.Revelle: The common meteor showers have very definite orbits. They're associated with the parent comets that these objects have originated from. And these orbits are very repeatable and in fact we actually cross these orbits twice a year.But not all meteors are as predictable. Large space rocks often enter the atmosphere, and blow up in powerful explosions above the Earth. Dr. Revelle has discovered that those random meteors come much more frequently than scientists previously thought.Revelle: The United States satellite systems that are currently in orbit also see meteors coming through the atmosphere, and they confirm one event that's about the size of the Hiroshima bomb every year. As you go to smaller sizes, there's at least a dozen events every year that pass through the atmosphere that distribute about 1000 tons of TNT into the air.We'll hear more about meteors in future programs. I'm Jim Metzner, and this is the Pulse of the Planet.