Complex ‘X-Files’ infrasound recorded from edge of space! Source unknown
A graduate student at the University of North Carolina at Chapel Hill who has a passion for designing, building and launching high-altitude balloons since his teenage years has stumbled upon strange and complex ‘X-Files’ sounds recorded by his infrasound microphones at 22 miles (36 kilometers) above the Earth’s surface.
Part of the High Altitude Student Platform (HASP) – an annual project conducted by NASA and the Louisiana Space Consortium meant to ignite and instigate student interest in space research – the infrasound microphone project was designed and built by Daniel Bowman. Through this microphone, Bowman eavesdropped on atmospheric sound waves at frequencies below 20 hertz aka infrasound. These sounds are below human hearing range, but the recording can be sped up to make them audible.
Bowman’s microphones were dangled from a helium balloon that flew above New Mexico and Arizona on Aug. 9, 2014. According to LiveScience, during the 9-hour flight the balloon, with its payloads, floated some 450 miles (725 km) and reached a height of more than 123,000 feet (37,500 meters). This region is near space and well above the region where airplanes fly, but below the boundary marking the top of the stratosphere, 62 miles (100 km) above the Earth’s surface.
The unique thing about Bowman’s experiment was that no other infrasound project has ever reached such high altitudes. Drifting over New Mexico, the infrasound sensors picked up a knotty mix of signals that scientists are still working to interpret.
“I was surprised by the sheer complexity of the signal,” Bowman said. “I expected to see a few little stripes.”
Though researchers haven’t been able to pinpoint the source of the complex signals, Bowman does provide some guesses.
- wind farm under the balloon’s flight path;
- crashing ocean waves;
- wind turbulence;
- gravity waves;
- clear air turbulence; and
- vibrations caused by the balloon cable.
“There haven’t been acoustic recordings in the stratosphere for 50 years. Surely, if we place instruments up there, we will find things we haven’t seen before,” Bowman said.
None of the sources mention ‘aliens’ as a possible origin.
In a bid to help reveal more about the strange sound and its possible sources, scientists have also planned another such experiment for the 2015 HASP balloon launch.
Infrasound are known to travel for long distances. Some of the terrestrial and non-terrestrial sources of infrasound waves include storms, earthquakes, volcanoes, avalanches and meteors. One of the best examples of infrasound waves as observed over long distances was during meteor explosion near Chelyabinsk on Feb. 15, 2013.
The meteor explosion generated ground motions and air pressure waves in the atmosphere. The permanent Global Seismographic Network (GSN) and EarthScope’s temporary Transportable Array (TA) sensors picked up the signals generated by the explosion.
Energy from the blast created pressure waves in the atmosphere that moved rapidly outward and around the globe. The blast also spread within the Earth as a seismic wave.
The two wave types–seismic wave and pressure wave–travel at very different speeds.
Waves in the ground travel quickly, at about 3.4 kilometers per second. Waves in the atmosphere are much slower, moving at about 0.3 kilometers per second, and can travel great distances.
GSN stations in Russia and Kazakhstan show the ground-traveling wave as a strong, abrupt pulse with a duration of about 30 seconds.
The atmospheric waves–referred to as infrasound–were detected across a range of inaudible frequencies and were observed at great distances on infrasound microphones.
When the infrasound waves reached the eastern United States–after traveling 8.5 hours through the atmosphere across the Arctic from the impact site in Russia–they were recorded at TA stations at the Canadian border.
The infrasound waves reached Florida three hours later, nearly 12 hours after the blast.
Infrasound sensors at TA stations along the Pacific coast and in Alaska also recorded the blast, but with signatures that were shorter and simpler than those recorded by stations in the mid-continent and along the southeastern seaboard.
The duration of the signals, and the differences between the waveforms in the east and west, scientists believe, are related to the way in which energy travels and bounces on its long path through the atmosphere.