Scientists Discover Strange Noises in the Stratosphere   

• Researchers from Sandia National Laboratories sent solar-powered balloons into the stratosphere to collect data from altitudes higher than those reachable by commercial jets. But when a balloon reached a zone between 10 and 50 km above the Earth’s surface, their instruments detected puzzling noises that were inaudible to the human ear. These low-frequency vibrations, called infrasound, repeated several times an hour and sounded like muffled whispers when sped up a few thousand times, intriguing researchers. Inspired by previous experiments involving weather balloons equipped with cameras and realizing the lack the research involving microphones on stratospheric balloons, the researchers decided to build their own. They attached microbarometers, originally meant to monitor volcanoes, to the giant solar balloons. That high up in the atmosphere, the instruments could capture the sounds of surface and buried chemical explosions, thunder, ocean waves, propeller aircraft, city sounds, suborbital rocket launches, earthquakes, and many more. The research team separated these atmospheric noises to investigate the sounds of unknown origin. The discovery of mysterious noises in the stratosphere adds an intriguing dimension to our understanding of Earth’s atmosphere. Though scientists cannot confirm the exact nature of these sounds, the experiment revealed possible new uses of the solar-powered balloons – exploring planets like Venus. Sean Jung Director