Atmospheric sound channels – good for sleuths but not UFOs

US army efforts in 1947 to put 'wiretapping' balloons in the mesosphere led to flying saucer tales but ultimately to scientists finding natural channels of communication

Seventy years ago a rancher near Roswell, New Mexico, found some peculiar wreckage of silver foil and sticks. An official US army statement claimed it was a "flying disc", leading to headlines that an alien flying saucer had been captured.

A second statement said the debris was just a weather balloon. The media accepted this version, although UFO enthusiasts still believe the Pentagon has a crashed extra-terrestrial spacecraft.