This brightly colored aurora shines above the telescopes of the Amundsen-Scott polar station at the South Pole. Like the northern lights, the aurora australis is also created by the interaction of the solar wind with the terrestrial magnetic field and the gas particles in the atmosphere.
Most of us still know the simple explanation for the northern lights from school: If the high-energy charged particles of the solar wind hit the earth’s magnetic field, they are deflected. The parallel magnetic lines protect the earth like a kind of Faraday cage. But in the vicinity of the poles this protective cage is permeable because the magnetic field lines run towards the magnetic pole there and are therefore almost perpendicular to the earth’s surface.
Because the charged particles of the solar wind move along the magnetic field lines, they can penetrate further into the atmosphere near the poles than in the temperate or low latitudes. They collide with the oxygen and nitrogen atoms in the air and temporarily stimulate them. When the atoms return to their ground state, they then give off the energy in the form of light of different wavelengths – the aurora is created.
Depending on the type of excited atoms and the energy they radiate, the resulting aurora can show different colors and shapes. Typically, oxygen emits green and red light, and nitrogen emits blue and purple light. The greenish aurora borealis that are visible here mostly arise at an altitude of almost 100 kilometers, while the reddish light is around 200 kilometers above the surface of the earth.
The polar researcher Benjamin Eberhardt took this snapshot near the Amundsen-Scott research station at the South Pole. It shows a multicolored Aurora australis and a falling star over the Antarctic. The telescopes can be seen on the ice, which are located in a special “dark sector” shielded from the station’s stray light.