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 ...

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 ...

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 ...