From more than 100,000 kilometers away they should observe nuclear weapons tests: Between 1963 and 1970, the United States shot in the context of the "Vela" program, a dozen satellites into space. These were to provide the Washington government with information on whether the Soviet Union adhered to the agreed prohibition of such experiments in the atmosphere, space and oceans.
Part of the flying scouts had in addition to detectors for X-ray, neutron and gamma radiation and optical instruments on board. One of them registered on September 22, 1979 a double flash of light over the South Atlantic, whose origin is still unclear. Time and again it has been speculated whether Israel or South Africa could have tested a nuclear weapon at that time. The matter is definitely not clarified until today.
A few years earlier, however, the Vela satellites had already registered huge atmospheric luminous events that had a less martial background: Researcher Bob Turman of the Sandia National Laboratories in Albuquerque, New Mexico, first reported in a 1977 publication by so-called Superbolts. These were luminous phenomena in thunderstorms, which he could prove in the satellite data. The special thing about it: The flashes were 100 or even 1000 times brighter than normal.
Away from the flash hotspots
In a recent publication in the journal "Journal of Geophysical Research: Atmospheres", a team led by Robert Holzworth of the University of Washington in Seattle now presents new insights into the gigantic discharges in the atmosphere. The researchers had evaluated data from 80 sensors of the World Wide Lightning Location Network from the years 2010 to 2018.
These sensors are looking for disturbances of radio reception caused by atmospheric processes. Analyzing the data, the team concluded that Superbolts are frequently found in places where experts never suspected them.
In the video: This is how it is when you are - well protected - struck by lightning
MIRROR ONLINE
There are some places in the world that are considered true lightning hotspots. The town of Kifuka in the Democratic Republic of the Congo is one of them: Every year, there are statistically 158 flashes per square kilometer. In the area around Lake Maracaibo in Venezuela there are even 233. (For comparison: in Germany's lightning strongholds such as the district of Garmisch-Partenkirchen or the Berchtesgadener Land, the value is about four).
Two billion lightning bolts examined
Holzworth and his colleagues have now been able to prove a total of 8171 Superbolts in the analysis of about two billion flashes. Interestingly, the extreme events were offside the classic hotspots. They mainly took place over open water in the northern hemisphere, the North Atlantic and the Mediterranean, for example.
The researchers were also able to show that especially the months between November and February showed above-average activity. Then autumn and winter prevail in the northern hemisphere. Normal flashes, on the other hand, are more likely to occur during warmer times of the year.
photo gallery
7 pictures
Flashes in Germany: KrawummA possible explanation for the miraculous mega-flashes and their behavior, the researchers also provide. Maybe the appearance above water has to do with the enormous intensity. Because there are no classic places for a lightning strike - high buildings, trees, electricity pylons or the like - build up an ever greater voltage difference, which is compensated only in the furious discharge of a Superbolts.
The accumulation in the cool season, in turn, the researchers explained that there is then a larger temperature difference between comparatively warm ocean currents and the cool atmosphere.
