NASA scientists have seemingly solved the mystery of fleeting flashes that have been seen emanating from Earth over the years by observers in space.
Originally discovered by legendary astronomer Carl Sagan in 1993, the puzzling flashes were first spotted in images taken by the Galileo spacecraft en route to Jupiter.
Although initially explained as reflections of sunlight off of bodies of water, contemporary researchers at NASA noticed something amiss with that conclusion.
Studying the Galileo images as well as new data from a NASA camera aboard NOAA's newly-launched Deep Space Climate Observatory, they realized that the enigmatic flashes also appeared over land.
Taking a new look at the mystery, scientists proposed that those flashes could be caused by ice crystals in the atmosphere.
A subsequent test of the hypothesis suggested that this is, indeed, the case as the angular conditions necessary for the reflections to be captured by the observatory matched in instances where the flashes were recorded.
Additionally, an examination of the weather where the flashes were seen indicated that those area were rife with cirrus clouds, which contain ice crystals, at the time of the incidents.
While the findings may disappoint UFO enthusiasts hoping that the flashes were signs of ET activity, we're guessing that, wherever he may be today, Carl Sagan is sporting a satisfied grin.