Add Yahoo as a preferred source to see more of our stories on Google. Solar-powered balloons are recording mysterious sounds below human hearing in the stratosphere. The unknown crackling could be the ...

Up, up in the air ... scientific solar-powered balloons have recorded some strange sounds in the stratosphere researchers cannot identify. Daniel Bowman and other researchers at Sandia National ...

Giant solar balloons were sent 70,000 feet up in the air to record sounds of Earth’s stratosphere — and the microphones picked up some unexpected sounds. The stratosphere is the second layer of ...

Scientists are picking up on some strange sounds in the second layer of our atmosphere that they haven't heard anywhere else. The stratosphere is a relatively calm layer of Earth's atmosphere, rarely ...