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.
The Case of the Missing Aurora
Explanation: Sometimes, near midnight, auroras suddenly stop . Nobody knows why. This nightside gap in aurora was confirmed recently by D. Chua ( U. Washington ) and colleagues in data from the Ultraviolet Imager onboard the Polar spacecraft. The gap appears from space as a slight break in a more full auroral arc surrounding a magnetic pole of the Earth. Pictured above are clouds and auroras occurring last August near Wildcat Mountain in Wisconsin .
| Date | October 21, 1998 |
|---|---|
| Credit | Credit: J. P. Dwyer |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |