‘Alien sounds’ recorded 22 miles above the earth
Mysterious hisses and whistles have been recorded 22 miles above the earth's surface using infrared microphones aboard a NASA student balloon experiment.
The sounds were recorded using infrared microphones that flew above New Mexico and Arizona. It is the first time an infrasound study has reached these heights.
The 'infrasounds' were captured by Daniel Bowman, a student at the University of North Carolina, according to a report in LiveScience.
The sounds can only be heard by human ears after speeding up the recordings and were picked up at frequencies below 20 hertz.