Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

September 1, 1998

A Colourful Aurora
Credit & Copyright: Stephen Barnes, Sky Optics

Explanation: A solar storm overtook the Earth on August 26th. The Earth survived unscathed, as usual, although many northerners reported an impressive display of aurora. Many of these aurorae changed rapidly, with patterns appearing and disappearing sometimes in less than a second. Out away from city lights, observers also reported an unusually spectacular array of colours. Some of these colours were captured in the photograph above. Solar particles that strike oxygen high in Earth's atmosphere cause rare, red aurorae, while oxygen lower to the ground will glow a more familiar green. Ionized nitrogen glows blue or red.

Tomorrow's picture: Saturn in Blue and Yellow

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.