Scientists saw a bright blue beam shooting upward from the clouds.
Blue lightning emissions can be difficult to detect from the ground, as these electrical discharges arise from the top of storm clouds. But from space, scientists can observe this cerulean light show.
On February 26, 2019, instruments aboard the International Space Station captured a blue beam that shot out of a cluster of clouds near Nauru, a small island in the central Pacific Ocean. The scientists described the event in a report published in the journal Nature .
image credit: ESA.
Scientists first saw five intense flashes of blue rays, each lasting between 10 and 20 milliseconds. Then the blue light emission fanned out from the cone-shaped cloud and spread out into the stratosphere.
These blue-ray emissions appear to occur when the upper region of a positively charged cloud interacts with the negative charge of the cloud-air boundary at the top.
The blue ray appears as a result of this electrical fault. Opposite charges swap places in the cloud and briefly equalize, releasing static electricity.
However, the properties of these blue lights and the altitude they reach are not well studied, the authors noted.
The blue-ray does not appear alone.
Before the appearance of blue light, four flashes with a small pulse of ultraviolet light emerged, the scientists noted. They identified these emissions as so-called elves, another known phenomenon from the upper atmosphere.
The team observed the flashes, elves, and blue light emission using the European Space Agency’s Atmosphere Interaction Monitor (ASIM). This is a collection of optical cameras, photometers, X-ray detectors, and gamma-ray detectors attached to a module on the space station.
image credit: ESA.
Finally, experts also suspect that phenomena in the upper atmosphere, such as blue rays, could affect the concentrations of greenhouse gases in the atmosphere since the ozone layer is located within the stratosphere where they occur.