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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.
An Airglow Fan from Lake to Sky
Explanation: Why would the sky look like a giant fan? Airglow . The featured intermittent green glow appeared to rise from a lake through the arch of our Milky Way Galaxy , as captured last summer next to Bryce Canyon in Utah , USA. The unusual pattern was created by atmospheric gravity waves , ripples of alternating air pressure that can grow with height as the air thins, in this case about 90 kilometers up . Unlike auroras powered by collisions with energetic charged particles and seen at high latitudes, airglow is due to chemiluminescence , the production of light in a chemical reaction. More typically seen near the horizon, airglow keeps the night sky from ever being completely dark.
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| Date | January 27, 2016 |
|---|---|
| Credit | Image Credit & Copyright: Dave Lane ; Rollover Annotation: Judy Schmidt |
| Authors & editors: | Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) |
| A service of: |
ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. |