Scientists Baffled After Balloons Record Mysterious Sounds Of Unknown Origin In Stratosphere

Scientists in the USA have heard a mysterious sound from the stratosphere region, and it has left them amused.

Around 50 kilometres over the surface of the Earth, the stratospheric area is comparatively peaceful and devoid of storms, turmoil, and commercial air activity.

Scientists in the USA have heard a mysterious sound from the stratosphere region of the atmosphere. Even though this stratosphere is known for being a peaceful region, the recent discovery where the source of the sounds were still not detected has puzzled many scientists. A group of US scientists from Sandia National Laboratories sent big, 6-7-meter-long solar balloons with microphones to record the sound.

Statement from A Scientist

"There are mysterious infrasound signals that occur a few times per hour on some flights, but the source of these is completely unknown," Daniel Bowman of Sandia National Laboratories said in a statement, as per WION. The noises were in the infrared spectrum, which is significantly beneath the audible range of human hearing and occurs at frequencies of 20 hertz (Hz) and below.

Technology Used by Researchers

The research team used micro barometers, a type of sound-gathering apparatus that can pick up low-frequency sounds.

The researchers constructed affordable, readily available solar powered balloons to carry these sensors into the air. They can climb up to almost 70,000 feet up in the air and record sounds effectively.

"Our balloons are basically giant plastic bags with some charcoal dust on the inside to make them dark," Bowman was quoted as saying by CNN.

"We build them using painter's plastic from the hardware store, shipping tape, and charcoal powder from pyrotechnic supply stores. When the sun shines on the dark balloons, the air inside heats up and becomes buoyant."

Challenges of Solar balloons

Even though the solar balloons are an excellent tool to record the sounds in high altitude and low frequency regions, there are several challenges  about it too.

"Solar balloons are a bit sluggish, and we’ve wrecked a few bushes when trying to launch them,” Bowman said. “We’ve had to hike down into canyons and across mountains to get our payloads. Once, our Oklahoma State colleagues actually had a balloon land in a field, spend the night, and launch itself back in the air to fly another whole day!”