Northern Lights Color

Winner in the 2023 IAU OAE Astrophotography Contest, category Still images with smartphones-mobile devices : Northern Lights-Color, by Jason Johnson

This photograph taken with a smartphone captures the ethereal beauty of the Northern Lights at Cassidy Point, Yellowknife, NT, Canada on 24 March 2023, at temperatures well below freezing (–29°C). The mesmerising dance of the Aurora Borealis (Australis), commonly known as the Northern (Southern) Lights, paints the night sky in striking hues. The aurora is a natural phenomenon caused by charged particles from the Sun interacting with Earth’s atmosphere, and being redirected by Earth’s magnetic field towards the north and south polar regions. The charged particles excite atoms and molecules in the atmosphere, resulting in a light display that varies in colour and form. The different colours of an aurora are determined by the gases (atoms and molecules) in Earth's atmosphere, the altitude of the aurora, the density of the atmosphere, and the energy of the charged particles. In general, green is attributed to oxygen molecules, red is associated with high-altitude oxygen molecules, purple and blue are associated with hydrogen and helium, and pink auroras are typically associated with nitrogen. On this particular night, the serene environment of Cassidy Point provided an unobstructed view of the lights. In the foreground, Aurora Village can be seen, a site renowned for organised tours to witness this spectacle.

Credit: Jason Johnson/IAU OAE (CC BY 4.0)