A NASA student was able to record mysterious alien sounds in the stratosphere of the Earth using infrared microphones fitted on a high altitude scientific balloon, according to News EveryDay.
Daniel Bowman, a student from the University of North Carolina, captured infra-sonic sounds with his balloon while conducting a scientific study for the Louisiana Space Consortium and NASA.
The project is called High Altitude Student Platform (HASP) and is conducted by NASA and the Louisiana Space Consortium every year.
The helium balloon was flying 22 miles above New Mexico and Arizona when the strange noises were recorded on Aug 9, 2014. Infrasound recordings have not been recorded in the stratosphere for 50 years.
The helium balloon had traveled for 9 hours across 450 miles at an altitude of 123,000 feet.
Bowman told Live Science that the captured infra-sonic sounds were kind of like The X-Files.
The discovery of the eerie noises has generated many theories as to what could have caused them.
Some said that the noises were signals coming from a wind farm under the balloon's path. Others pointed out that it could have been the sound of ocean waves or wind turbulence the helium balloon may have encountered during its flight.
Vibrations from the balloon's cable, gravitational waves and turbulence from clear air were other explanations given by people.
Another HASP research balloon is set to launch this year, which researchers think could help explain the strange infrasound further.
Infrasonic sounds, which are known to travel long distances, can only be heard at a frequencies below 20 hertz. Earthquakes, storms, volcanoes and avalanches are some sources of infrasound waves.