In what came as a chance finding, first time during the last 50 years, has left the NASA scientists befuddled.

As reported by LiveScience, Daniel Bowman, a doctoral student at the University of North Carolina at Chapel Hill, on Aug. 9, 2014, observed mysterious hisses and sounds, some 22 miles (36 kilometers) above the earth's surface, when he released a helium balloon having a hi-tech microphone affixed to it. This was as part of NASA's High Altitude Student Platform (HASP) experiment. They said 'balloon' that flew for 9-hours over New Mexico and Arizona, was the original work of Bowman himself.

The sounds, which allegedly came from the edge of space, have been attributed as 'infrasounds', not easily audible to the human years. These can be heard only by using infrared microphones, after increasing the tempo of the captured sounds.

"I was surprised by the sheer complexity of the signal. I expected to see a few little stripes. It sounds kind of like 'The X-Files'", Bowman told LiveScience.

Infrasonic sounds are low frequency sounds caused majorly by natural occurrences like earthquakes and volcanoes and are capable of traversing long distances. The current infrasounds, the source of which is still unclear, were captured at frequencies below 20 hertz. Scientists are contemplating various reasons for the weird sounds, ranging from wind turbulence, clear air turbulence, presence of a wind farm under the balloon's flight path, vibrations in the balloon cable to gravity waves and ocean waves.

NASA plans to send more balloons to investigate further, as no previous infrasound experiment has reached so high up in the atmosphere. So much so, that the HASP has already prepared its payload for the 2015 balloon launch. The HASP is a joint research project of NASA and Louisiana Space Consortium that aims to spark student interest in space research. It has already launched more than 70 such experiments across the US, since its inception in 2006.