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Credit & Copyright: Lance McVay
Explanation:
Some auroras
can only be seen with a camera.
They are called sub-visual and are too faint to be seen with the unaided eye.
The reason is that the human eye
only accumulates light for a fraction of a second at a time,
while a camera shutter can be left open indefinitely.
When photographing an already picturesque scene above
Juneau,
Alaska,
USA,
a camera caught green sub-visual aurora near the horizon.
Auroras
are sparked by
energetic particles from the
Sun impacting the
magnetic environment
around the Earth.
Resultant energetic particles such as
electrons and
protons
rain down near the Earth's poles and impact the air.
The impacted
air molecules
temporarily lose electrons, and when
oxygen molecules
among them reacquire these electrons, they emit
green light.
Auroras
are known to have many
shapes and
colors.
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NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day
Publications with keywords: aurora
Publications with words: aurora
See also:
- APOD: 2025 January 7 Á A New Years Aurora and SAR Arc
- APOD: 2024 December 8 Á Aurora around Saturns North Pole
- APOD: 2024 October 16 Á Colorful Aurora over New Zealand
- APOD: 2024 October 13 Á Aurora Timelapse Over Italian Alps
- Northern Lights, West Virginia
- Aurora Australis and the International Space Station
- APOD: 2024 June 26 Á Timelapse: Aurora, SAR, and the Milky Way