Discoveries

June 01, 2023

The Sound of Space

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Low-cost solar balloons are revealing to scientists fascinating and mysterious sounds coming from Earth’s stratosphere, CNN reported.

The stratosphere is our planet’s second layer of the atmosphere, which also contains the ozone shield that protects Earth from harmful ultraviolet radiation from the Sun.

Lead researcher Daniel Bowman and his colleagues sought to investigate the soundscape in the stratosphere by analyzing the layer’s infrasound – low-frequency sounds that are inaudible to the human ear.

For their study, they created a series of solar balloons using affordable items that can be bought from any local hardware store.

“Each balloon is made of painter’s plastic, shipping tape, and charcoal dust,” Bowman said via email. “They cost about $50 to make and a team of two can build one in about 3.5 hours.”

These balloons were then attached with infrasound recorders and GPS trackers, before being sent up to an altitude of about 70,000 feet.

The researchers collected a rich cacophony of sounds between 2016 and April 2023. These included chemical explosions, thunder, rocket launches, colliding ocean waves, and earthquakes.

But they also recorded some crackles and rustling of unknown origins.

“They are almost certainly mundane, maybe a patch of turbulence, a distant severe storm … but it’s hard to tell what is going on sometimes due to the lack of data up there,” Bowman suggested.

The team plans to further investigate these sounds.

Meanwhile, their inexpensive invention could be used to venture into uncharted territories, such as Venus and beyond.

By carrying scientific instruments above or within the planet’s clouds, it could pave the way for a test flight, lasting several days, as a precursor to more intricate and expansive missions.

This story originally appeared in the June 01, 2023 newsletter, Balkan Malaise.