VLF "ear" listens for falling meteorites

17 Jun 2002

Los Alamos National Laboratory researcher Doug ReVelle keeps an "ear" to the sky listening for falling objects that travel many times faster than the speed of sound. And each year at least one fairly large extraterrestrial object comes rumbling into Earth's atmosphere, said ReVelle, who presented information about using very low-frequency sound waves to detect meteors 18 December at the American Geophysical Union's Fall Meeting.

Using data from listening stations originally set up to monitor underground nuclear explosions, ReVelle hears the infrasonic signature created when meteors enter the atmosphere. "Each year, we see at least one object entering the atmosphere that's about six meters in diameter," he said. "These make an infrasonic signal similar to what you'd see from a 15-kiloton explosion"."