For the first time in the last fifty years, eerie sounds have been recorded by a scientist aboard a NASA student balloon experiment. Last year, the mysterious whistles and hisses were captured by powerful infrasound microphones around 36 kilometers or 22 miles above the surface of the Earth.

The equipment was designed and constructed by a graduate student called Daniel Bowman; he has obtained his degree from the University of North Carolina in Chapel Hill. The instruments are so powerful that they can eavesdrop on sound waves with frequencies below20Hz, for instance, atmospheric infrasound.

For those who don’t know: the frequency of infrasound is beyond the human hearing ability; however, humans can hear them by increasing the speed of the recordings.

The infrasound sensors created by Bowman kept on dangling from the helium balloon used for the experiment as it was flying over Arizona and New Mexico on August 9, 2014. This experiment is one among the ten payloads flown on the HASP or High Altitude Student Platform in 2014.

Here, it must be mentioned that high altitude balloon flight is one of the most important annual events organized by NASA. NASA does it in partnership with the Louisiana Space Consortium. The event is organized every year with the sole aim of encouraging more and more students to take part in space research.

Since 2006, we have seen HASP launch more than seventy experiments, each of which has been designed by college students living in different parts of the United States.

The balloon recording the eerie sounds took a nine-hour flight. During this flight, the balloon along with all its payloads covered a distance of around 725 km or 450 miles and reached an altitude of over 37,500 meters or 123,000 ft.

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Bowman, when speaking about his experiment, said that to date, not a single infrasound experiment has managed to reach such high altitudes.

When Bowman’s balloon turned towards New Mexico, the sensors captured a knotty combination of signals. Scientists are now working for interpreting those signals. This was revealed by Bowman on April 23, during the annual meet of the Seismological Society of America.