Scientists have figured out what causes pulsating auroras, a rarely seen form of northern lights in the night sky. And it was partly thanks to a lucky observation of the phenomenon in Canada.
From a Japanese satellite, researchers measured these factors from a point near the Earth:
- Waves in the plasma — a gas of charged particles — in the area of outer space surrounding Earth’s atmosphere called the magnetosphere.
- Levels of particles called electrons that can generate auroras.
Then they tracked the particles to The Pas, Man., where an all-sky camera had captured images of the resulting pulsating aurora. The researchers obtained the data with the help of the Canadian Space Agency.
Satoshi Kasahara, the University of Tokyo planetary scientist who led the study, and his colleagues compared the data from Earth and from space.
They confirmed that pulsating auroras are generated when clumps of plasma waves in the magnetosphere, the region of space affected by the Earth’s magnetic field, intermittently herd and shove aurora-causing electrons into the Earth’s magnetic field lines.
That causes bursts of electrons to rain down into the Earth’s atmosphere, where they can interact with particles there to produce a colourful light show. Normally, they just remain in space.
The researchers published their findings today in the journal Nature.
Many Canadians have been dazzled by the aurora borealis that they see as colourful curtains and ribbons of light that dance across the sky.
Such “active” auroras are actually less common than blinking patches of light known as pulsating auroras, which can last all night, every night, said Allison Jaynes, a plasma and…