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.
June 19, 1996
Aurora: Curtains in the Sky
Credit and Copyright: Michael Dolan (Michigan Tech.)
Explanation: Looking out over Lake Superior at dusk you see Venus (lower left) and ... curtains? Like an ant looking up at window curtains, aurora frequently appear as huge flowing light displays. These colourful, often spectacular phenomena are most frequently visible from locations near the Earth's poles. Aurora are caused by electrons from the solar wind funneling to Earth along magnetic field lines, and striking atoms and molecules in our atmosphere. Auroral colour is determined by which atmospheric ions are struck and recombine to form neutral atoms. Hourly updates of auroral sightings are posted to the WWW. It is still controversial whether aurora make any sound audible from the ground. If you think you have "heard an aurora," please report it!
Authors & editors:
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
&: Michigan Tech. U.