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Friday, 26 October, 2001, 15:54 GMT 16:54 UK
Lights snapped from space
Double aurora, Nasa
The two auroras are a mirror image of each other
By BBC News Online's Helen Briggs

Red and green lights dance in the sky above the North and South poles.

The two lights - the Aurora Borealis and Aurora Australis - appear to be a mirror image of each other.

This is the first time that we have seen both auroral ovals simultaneously with such clarity

Nicola Fox, Nasa Goddard Space Flight Center
This picture was taken by a spacecraft during a recent space weather storm.

It is the first time Northern and Southern Lights brightening at the same time at opposite ends of the Earth have been captured on film.

Captain Cook

The idea that the auroras are related in some way has long been suspected. It was first mooted by the famous explorer Captain Cook in the 18th Century.

While sailing the South Pacific he noted "a phenomenon appeared in the heavens in many things resembling the Aurora Borealis".

Historical documents in China later revealed that lights were seen on the same night - 16 September 1770 - in the Northern hemisphere.

The current images were taken on 22 October by instruments aboard Nasa's Polar probe.

Dr Nicola Fox, the spacecraft's operations manager, said: "This is the first time that we have seen both auroral ovals simultaneously with such clarity.

"With these images, we have the ability to see the dynamics of conjugate auroras."

Aurora season

Auroras happen when fast-moving particles (electrons and protons) trapped in the magnetic field around the Earth collide with the gases of the upper atmosphere.

Northern Lights, AP
Northern Lights: The view from the ground
During violent magnetic storms, the particles travel along energised magnetic field lines that are grounded near the North and South poles.

This creates displays of coloured lights in 4,023 km (2,500 mile) bands around each pole.

Autumn evenings are a good time to spot the Northern Lights.

Space experts are predicting that they may be seen in high latitudes for the second weekend in a row on 27 and 28 October.

See also:

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