May 24 (NHK) - A curator at a museum in Japan has captured rare images of mysterious upper atmospheric phenomena known as sprites.
Sprites, which occur at altitudes of 50 to 90 kilometers, are believed to be electric discharges like lightning, but details of their mechanism are not clear. They are difficult to observe, as they often occur above thunderclouds.
Fujii Daichi of the Hiratsuka City Museum in Kanagawa Prefecture took the images of two sprites seen between clouds from the ground in Shizuoka Prefecture on April 7. The sprites are estimated to have been around 100 kilometers away, and images taken that close are very rare.
The sprites appeared about 10 minutes apart, each lasting 0.1 seconds. The first was in the shape of four slim columns, and the second was four triangles.
