Space Agency NASA has recorded more than hundreds of flashes, flickering on the planet, and have figured out the riddle that tormented astronomer Carl Sagan more than two decades. These flashes are so powerful that they can be seen even from space. Initially it was thought that they are caused by reflected light of the Sun falling on the ocean surface. But then the same flash NASA began to celebrate on the ground. And at that time no one could answer what is their source.
“We found several very bright flashes on the ground. When I first saw them, I thought that maybe somewhere there is water – a lake, which reflects the sun’s rays. But the outbreak was so strong that it was hardly connected with the water,” — said an employee of the space flight Center of NASA Goddard Alexander Marshak.
In 1993 the famous American astronomer Carl Sagan remarked on the images of Earth taken by the space probe “Galileo”, an unusual flash on its surface. The device was launched four years earlier to study Jupiter and its moons, but Sagan and his team decided to take advantage of one of the spans of the device past the Earth and to collect data that would indicate the presence of life on our planet. The idea was that if the machine was able to identify signatures of life on Earth from a great distance, then in theory the same way it can be done by our cosmic neighbors, if such exist, of course, and to determine whether our planet is inhabited.
On the images from Galileo, scientists have discovered bright flashes of light as if reflected from mirrors. But Sagan and his team noted the presence of flares only in those places where our planet is covered with water.
“A careful examination of paintings of the vast oceans and their coastlines on the satellite images revealed the presence of amazing mirror reflections in the ocean. On earth such reflections were not observed,” — said at the time, a team of researchers.
The news that 24 years later NASA was able to detect 866, such as bright flashes of light in between June 2015 and August 2016, has caused an unprecedented interest among the scientific community. But the real “shock” was that all these outbreaks, the Agency observed on earth.
Below you can see a video created by NASA with the camera Earth Polychromatic Imaging Camera (EPIC) installed on Board the spacecraft Deep Space Climate Observatory (DSCOVR), used for observations of the Sun and Earth.
When the team at NASA decided to compare images obtained with the EPIC camera and the Galileo mission, they realized that Sagan and his team missed one very important detail – in fact the older photos on earth also had such a bright flash. Decided finally to figure out what is this phenomenon, the team of Marshak catalogued everything seen by the cameras of the Galileo and EPIC flash, and created a detailed map of their location. Scientists have suggested that if these outbreaks are the result of reflection of sunlight, in this case, they could only be seen in certain places on our planet where the angle between the Sun and Earth were the same with respect to the angle between the spacecraft and the planet. Only in this case the camera would be able to catch those flashes. Of course, the possibility of lightning, scientists also thought, but quickly ruled out this possibility.
“Lightning no matter the location of the Sun relative to the camera is EPIC,” said Marshak.
In order to find out what actually causes these reflections, the research team decided to study the image of water, but not on the ground and in the atmosphere. Using data from the EPIC camera, they have created a map on which was marked the exact coordinates of the sources of the investigated outbreaks. It turned out that their sources are at a height of 5 to 8 kilometers above the surface – where usually formed Cirrus clouds containing large amounts of ice crystals.
When scientists modeled the movement direction of the solar light reflected from the alleged ice crystals, it was found that these crystals must have an almost horizontal angle to produce a similar effect. The results were compared with the image data of the EPIC cameras and Galileo, and they matched.
“The source of these outbreaks is definitely not on earth. This source is definitely ice, and likely the sunlight reflected from its horizontally arranged particles”, says Marshak.
Research is still awaiting a critical review, and some aspects of discovery after verification, can change. Researchers, in turn, now I want to find out how often this phenomenon with horizontal ice crystals and what level of sunlight in this case is reflected from our atmosphere.
But the mystery Sagan solved is definitely not one of those signs of life that he once sought.
NASA has solved the mystery of hundreds of mysterious flashes near the Ground
Nikolai Khizhnyak