Auroras over Tromsø, Norway

Auroras over Tromsø, Norway

Photographer Eva Kristiansen: "Queen Aurora didn't just dance—she reigned with all her colors and power. This was nature performing unforgettable dramas. And it's true, the autumn nights hold their own kind of magic."

Auroras are produced when the Earth's magnetosphere is sufficiently disturbed by the solar wind that the trajectories of charged particles in solar wind and magnetospheric plasma, mainly in the form of electrons and protons, precipitate them into the upper atmosphere (thermosphere/exosphere) due to Earth's magnetic field, where their energy is lost. The resulting ionization and excitation of atmospheric constituents emits light of varying color and complexity. [Wikipedia]

Solid Colored Aurora

Green is common at the upper latitudes, while red is rare. On the other hand, aurora viewed from lower latitudes tend to be red.

Element Emission Colors

Oxygen: The big player in the aurora is oxygen. Oxygen is responsible for the vivid green (wavelength of 557.7 nm) and also for a deep brownish-red (wavelength of 630.0 nm). Pure green and greenish-yellow aurorae result from the excitation of oxygen.

Nitrogen: Nitrogen emits blue (multiple wavelengths) and red light.

Other Gases: Other gases in the atmosphere become excited and emit light, although the wavelengths may be outside of the range of human vision or else too faint to see. Hydrogen and helium, for example, emit blue and purple. Although our eyes cannot see all of these colors, photographic film and digital cameras often record a broader range of hues.

Aurora Colors According to Altitude

Above 150 miles: red, oxygen

Up to 150 miles: green, oxygen

Above 60 miles: purple or violet, nitrogen

Up to 60 miles: blue, nitrogen

The Colors of the Aurora (National Park Service)

https://www.nps.gov/articles/-articles-aps-v8-i1-c9.htm

Image Credit: Eva Kristiansen 

Image Details: Nikon D850 Nikkor 14-24mm Iso 1600, f/2.8, 2.5 sec.
Eva's website: https://www.instagram.com/xevitak/
Image Date: Oct. 1, 2025

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