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 ...

The unknown crackling could be the sound of distant thunderstorms, falling meteors, or turbulence. Listen to the sounds a balloon hears 12 miles above Earth: from ocean waves to volcanic eruptions.

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 ...