aurora borealis = Northern lights.
aurora australis = Suthern lights.
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The colour depends on the quality of the air.
Aurora is the Roman goddess of dawn.
She's pictured as winged woman in a chariot with 4 horses, "pooring" the dawn over the earth.
Michelangelo made a (famous) beautiful statue of her that was used as tombstone at the grave of Lorenzo de' Medici in Florence.
