The research that made the sounds available was part of NASA’s High Altitude Student Platform. It is not the first recording of atmospheric infrasound made so far but it is the first that is captured at a high altitude.
David Bowman, a student at North Carolina, recorded the sounds using infrasound microphones during a balloon experiment in Arizona and New Mexico. The balloon, which was designed by Bowman, was equipped with infrasound sensors and could go up to 123,000 feet above the ground. It travelled for nine hours, on the 9th of August 2014. It was the first time infrasound was recorded at such a high altitude. Infrasound has a frequency lower than 20 Hz. This constitutes the limit of human hearing, which becomes less sensitive when this frequency decreases.
Thus, the recorded sounds are inaudible to humans as long as the recordings are not sped up. According to him, this is the first time acoustic recordings have been captured in the stratosphere within the last 50 years. Therefore, if the proper technology were to be employed there, scientists could be amazed at the findings: “I was surprised by the sheer complexity of the signal. I expected to see a few little stripes,” he added. For now, it was impossible to tell where the sounds came from, since infrasound can travel very long distances.
The researchers who listened to the sounds said that most of the noises have been unheard before and are trying to figure out what might have produced them. Although it is not clear yet what their sources are, the theories include relating them to ocean waves, the balloon’s flight path or vibrations produced by its cables, planes, air conditioning from buildings and wind turbulence.
Even if extraterrestrial communication is not completely ruled out, the scientists said it is highly unlikely that we are dealing with alien sounds: ” Sound cannot travel through space, so whatever is generating it must be located within about 140 km (approximately 90 miles) of the Earth’s surface,” David Bowman explained.
The acoustic signals are available to people who want to listen to them online.
Image Source: Telegraph