SPRITES AND COSMIC RAYS: Last night, cameras in Czechia recorded a magnificent display of sprites leaping up from a thunderstorm in neighboring Austria. Photographer Martin Popek of Nýdek, Czechia, selected this specimen from many frames he recorded:
“The storm was about 390km away,” says Popek, “and the sprite was huge. It stretched 50 km to 90 km above the ground below.”
Sometimes called “space lightning,” sprites are a true space weather phenomenon. They inhabit the upper atmosphere alongside auroras, meteors and noctilucent clouds. Some researchers believe they are linked to cosmic rays: subatomic particles from deep space striking the top of Earth’s atmosphere produce secondary electrons that, in turn, could provide the spark that triggers sprites.
The link to cosmic rays is particularly interesting at this time. Despite a brief reduction in cosmic rays last week caused by the sweeping action of a passing CME, cosmic rays are intensifying. For the past two years, space weather balloons have observed a steady increase in deep space radiation penetrating our atmosphere. This increase is largely due to the decline in the solar cycle. Flagging solar wind pressure and weakening sunspot magnetic fields allow more cosmic rays into the inner solar system–a trend which is expected to continue for years to come. These changes could add up to more sprites.
Although sprites have been seen for at least a century, most scientists did not believe they existed until after 1989 when sprites were photographed by cameras onboard the space shuttle. Now “sprite chasers” routinely photograph sprites from their own homes. “I used up a Watec 910HX security camera with UFOCapture software to catch my sprites,” says Popek.