X-rays Hidden in Northern Lights

The first time anyone sees the Northern Lights, it’s apparent there’s a ghostly and sometimes colorful field of energy enveloping Earth. The Chandra X-ray Observatory’s scan of the glowing aurora recently revealed something equally as peculiar: The electrified ribbons of the Northern Lights glow and shimmer in X-rays.

The X-rays were discovered 100 kilometers above Earth by a team of scientists led by Dr. Ron Elsner of NASA’s Marshall Space Flight Center in Huntsville, Ala. The team searched the skies above our planet — and below Chandra — 10 times over a four-month period in 2004. The observation was also the first time the telescope has focused its aperture on Earth.

Auroras are triggered by solar storms that eject clouds of rapidly moving, charged particles. When the clouds of solar particles reach Earth, they are deflected back by the planet’s magnetic field.

The collision sends electrons trapped inside the field spiraling down to the North and South Poles. The electrons fall to Earth and slam into atoms in the atmosphere, producing X-rays and the shimmering waves of auroras visible across the night sky. Auroras seen in the Northern Hemisphere are called “aurora borealis,” while those observed in the Southern Hemisphere are known as “aurora australis.”


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