When Oscar Hines, a 13-year-old from Unadilla, was visiting family on a holiday trip to Tennessee, he found what turned out to be a weather balloon.
A weather balloon is a small instrument package in a white Styrofoam box connected to a large latex balloon filled with hydrogen.
The hydrogen balloon quickly rises, and floats up to around 100,000 feet before bursting. After it bursts, a parachute deploys, allowing the instrument pack to slowly fall back to earth.
While the instruments are ascending, they send back information about the atmosphere by a radio signal.
The balloon sends back readings of temperature, dewpoint (humidity), wind, and air pressure. That data can then be plotted to produce a vertical snapshot of the atmosphere.
It's also used to help set the current conditions for computer weather models that forecast future weather conditions.
About half of the National Weather Service forecast offices in the U.S. launch two weather balloons each day in order to obtain a more complete picture of the upper atmosphere.
It's estimated close to 10,000 sites around the world launch similar balloons.
The balloon Oscar found was launched on the evening of August 31, 2012 from the NWS office in Nashville, TN. It only drifted about 10-15 miles before falling back to the ground in a wooded area. It sat there for more than three months until Oscar found it.
Winds aloft can be much stronger than at the ground.
It's not uncommon for weather balloons to drift 100-200 miles from where they're launched. Although some are found, and the instruments can be refurbished, it's estimated that less than 10% of launched balloons are actually found and returned.