The balloon carries an infrasound microscope that is able to record sound waves in the atmosphere at frequencies lower than 20 hertz. The device is floating just 22 miles above the Earth when it picked up the strange sound.
It was Daniel Bowman, a student from the University of North Carolina, who designed and built the balloon equipment used in the study. The initial program managed by NASA and the Louisiana Space Consortium tested the flight of the equipment where they captured sounds from the atmosphere of Arizona and New Mexico.
It was just one of the ten experiments flown atop of the High Altitude Student Platform that successfully picked up the sounds.
The said program was able to launch more than 70 student experiments in search of a successful project since 2006.
As that one balloon fly over the height of 37,500 meters above Earth for 9 hours, which is just below the top of the stratosphere and higher than the flight height of airplanes, it got the record of the highest point an equipment carrying infrasound has ever reached.
But the record is not all that, the sound captured by the balloon is what researchers claimed as a signal that they never encountered before.
As Bowman has said, “It sounds kind of like ‘The X-Files’.” There is some possibility that the sound might have come from another alien life, but may also originate from wind farms, crashing ocean waves, atmospheric turbulence, gravity waves, and vibrations formed by the balloon cable.
Bowman reported, “I was surprised by the sheer complexity of the signal. I expected to see a few little stripes,” as he was pertaining to the visual representation of the sounds through spectrogram detailing. The frequency range below 20 hertz is not audible to human hearing frequency, so the team adjusted it faster during the analysis.
He added, “There haven’t been acoustic recordings in the stratosphere for 50 years. Surely, if we place instruments up there, we will find things we haven’t seen before.”
Infrasound carried at great distances from its source is usually formed by low-frequency wave-creating phenomenon, such as earthquakes, volcanic eruptions, thunderstorms and meteor showers. Scientists have long used infrasound detectors to monitor weather and geologic activity all over the planet. NASA also plans to use infrasound detectors on the much-awaited Mars mission.