APOD
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.
A Complete Aurora
Explanation: Explanation : Aurora frequently make complete rings around a pole of the Earth. This particular “ crown ”, visible in orange near the top of this image , was taken by the orbiting Polar spacecraft about one year ago and released by NASA last month. A complete aurora l oval is normally hard to photograph because part of it usually occurs over a brightly sunlit portion of the Earth. Polar 's Earth Camera , however, can be programmed to filter out all but a certain type of ultraviolet light . In this “color”, atmospheric oxygen can glow brighter than reflected sunlight. People with normal eyesight living near the Great Lakes in North America would have been able to see this aurora , were it not daytime!
| Date | April 2, 1997 |
|---|---|
| Credit |
A Complete Aurora Credit: L. A. Frank, J. B. Sigwarth et al. (U. Iowa), Polar, VIS, NASA |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |