Aurora Borealis (Northern Lights)
A collection of photograph of Fact or Fiction Aurora photographs taken by friends and subscribers.
A rip in the sun’s atmosphere sends out strong gusts of solar wind which slams into Earth. As our planet plows through this cosmic cloud, an influx of charged particles is buffeting its magnetic field and igniting what’s known as a geomagnetic storm.
When the bursts of particles hit Earth’s magnetic field, they create geomagnetic storms. On rare occasions, such storms can damage electrical grids and temporarily knock out radio and satellite telecommunications. Any communications loss could cause air traffic controllers to reroute long-duration plane flights over the Arctic.
Geomagnetic storms also naturally funnel solar particles down into our atmosphere toward the Poles. The particles then smash into oxygen and nitrogen molecules, infusing them with energy and causing them to glow, creating colorful auroras.
Visual forms and colors
- Red: At the highest altitudes, excited atomic oxygen emits at 630.0 nm (red); low concentration of atoms and lower sensitivity of eyes at this wavelength make this color visible only under more intense solar activity. The low amount of oxygen atoms and their gradually diminishing concentration is responsible for the faint appearance of the top parts of the “curtains”. Scarlet, crimson, and carmine are the most often-seen hues of red for the auroras.
- Green: At lower altitudes the more frequent collisions suppress the 630.0 nm (red) mode: rather the 557.7 nm emission (green) dominates. Fairly high concentration of atomic oxygen and higher eye sensitivity in green make green auroras the most common. The excited molecular nitrogen (atomic nitrogen being rare due to high stability of the N2 molecule) plays a role here, as it can transfer energy by collision to an oxygen atom, which then radiates it away at the green wavelength. (Red and green can also mix together to produce pink or yellow hues.) The rapid decrease of concentration of atomic oxygen below about 100 km is responsible for the abrupt-looking end of the lower edges of the curtains. Both the 557.7 and 630.0 nm wavelengths correspond to forbidden transitions of atomic oxygen, slow mechanism that is responsible for the graduality (0.7 s and 107 s respectively) of flaring and fading. (Wikipedia)
These amazing photographs were taken by Alet Igland from Bergen, Norway.