Ultra-sensitive microphones aboard a NASA student balloon, floating at the edge of space has captured infra-sonic sounds. The sound could be from alien planets or it could be the sound from wind in the balloon’s path, to ocean waves, gravity waves and clear air turbulence.
Others suggest that the noises may be coming from movements from the balloon cable itself. However, the NASA-backed project now plans to send another payload to record more of these strange noises later this year, LiveScience reported.
Originally, the sounds were captured by Daniel Bowman, a student at the University of North Carolina at Chapel Hill. “There haven’t been acoustic recordings in the stratosphere for 50 years,” Bowman was quoted as saying. “Surely, if we place instruments up there, we will find things we haven’t seen before,” he noted.
Bowman had released infrared microphones on a helium balloon above New Mexico and Arizona in August as part of the High-Altitude Student Platform study and the balloon floating at 725 km across the Earth’s surface, reached a height of more than 37,500 metres.
Infrasonic sounds are produced by waves at frequencies below 20 hertz and sounds at those frequencies are inaudible to the human ear. Another feature of infrasonic sound is that it travels large distances and hence the student was able to record them.