The mysterious hisses and whistles were recorded 22 miles above Earth by Daniel Bowman, a graduate student at the University of North Carolina at Chapel Hill. The microphone picked up atmospheric infrasound or sound waves too low to be heard by human hears unless the recordings are sped up.
The microphones dangled from a helium balloon that flew above New Mexico and Arizona in August 2014. Bowman described the sounds as “like the X-Files.” Although alien life is not readily an assumption, scientists remain unclear about where the sounds came from. Current predictions include noise from a wind farm, ocean waves, turbulence or vibrations caused by the balloon cable.
“I was surprised by the sheer complexity of the signal," Bowman said. "I expected to see a few little stripes."
Scientists plan to send more devices up in the air in order to learn more about these mysterious sounds.
“Surely, if we place instruments up there, we will find things we haven't seen before," Bowman said.