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 ...

WEBVTT THEY HAVE CALLED THE CITY, AND AT TIMES CALLED 911. WITH A HUNDRED 50,000 SPECTATORS EVERY YEAR, IT IS NO SURPRISE BALLOON FIESTA CAN GET A LITTLE LOUD. EVERYTHING FROM NEWS HELICOPTERS TO THE ...

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 ...