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 ...

Think about it: you're at a birthday party, surrounded by colorful decorations, when suddenly a sharp crack splits the air. The most common source of fear is the sound of balloons popping, making it a ...

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 ...

At first listen, Earth’s stratosphere seems calm and quiet. But when researchers launched solar-powered balloons up 70,000 feet, they detected a hidden acoustic world — including mysterious noises ...

Daniel Bowman sends cell phones into the stratosphere aboard solar-powered hot-air balloons. You might be surprised what sounds they record up there. These balloons listen to the Earth from a dozen ...