The origin of the mysterious reflections of light on the Earth
NASA solves the mystery that had in vile to Carl Sagan more than 20 years ago
Twenty-four years ago, back in 1993, glimpses of light from Earth were detected by Carl Sagan, an astronomer and mythical presenter of the Cosmos program, in images captured by NASA’s Galileo spacecraft. From then on these reflections disconcerted the entire scientific community; nobody knew the explanation. That strange bright source remained an unresolved enigma for more than two decades.
From 2015 to August 2016, NASA’s Ground Polychrome Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR) had discovered 866 similar flashes worldwide. This helped to end the mystery; NASA finally found a compelling reason.
The flashes from EPIC, NASA video
The new team, studying the old photos taken by Galileo and comparing them with the current ones, realized that Sagan had overlooked a rather crucial detail: the flashes detected in 1993 actually came from the earth, although they always believed that they were coming of the ocean.
Everything indicates, according to the latest analysis, that the reason for these reflections are not the rays of the sun reflecting in large areas of water – the first hypothesis considered – but a rather unusual but nothing paranormal phenomenon: flying ice crystals. More precisely, small ice crystals floating horizontally in the sky at high altitudes on which sunlight is reflected. The team that analyzed the images found a perfect pattern between the reflections and the angle of the sun. To test their theory, they plotted the angles of the flashes and measured the height of the clouds, which revealed the presence of cirrus clouds, made up of ice crystals. These are formed due to the low temperatures in the lower layers of the atmosphere (5 to 8 km above the surface).
“It’s definitely ice, and certainly the reflection of the sun impacting horizontally on the particles,” explained Alexander Marshak, assistant scientist at the DSCOVR.
This discovery is due not only to the team of scientists, but also to Big Data. The amount of information that was extracted from the images taken by NASA satellites would have been unabashed by scholars other than the existence of this new technology. A process similar to that used to search for habitable planets in the universe: millions have been found, but not all present conditions necessary for life. It is the software that makes it possible to classify them.