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Asked by: Tony McCrossan, Dublin
Produced by fast-moving particles from the Sun smashing into molecules in the upper atmosphere, the Aurora Borealis is normally thought of as something visible only above the Arctic Circle. Yet at times of high solar activity, they can be seen much further south: during the great solar storm of August and September 1859, the colours typical of aurorae were seen in Honolulu, just 21° north of the equator.
Historians have uncovered evidence suggesting that the southern hemisphere counterpart of the Northern Lights, the Aurora Australis, may have been witnessed even closer to the equator, with reports of the phenomenon being seen from Samoa in 1921, at a latitude of 13° south, and a disputed report from Singapore at just 8° south during the storm of 25 September 1909.