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
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

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

< Archive | Index | Search | Glossary | Education | About APOD >

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.