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.

January 1, 1997

Aurora Over Circle, Alaska
Credit and Copyright: Dick Hutchinson

Explanation: Aurora can make spectacular sights. This particular aurora was photographed hovering over the town of Circle, Alaska. Although Aurora might first appear to be moonlit clouds, they only add light to the sky, and hence can not block background stars from view. Called "northern lights" in the northern hemisphere of the Earth, aurora are caused by charged particles streaming from the Sun entering the Earth's atmosphere. If viewed from space, aurora glow in X-ray light as well as in the visible! Several WWW sites can tell you if aurora are predicted to be visible in your area.

Tomorrow's picture: Bubbles and Arcs in NGC 2359

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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