polarlichtern

Polarlichtern, commonly referred to in English as auroras, are natural light displays that occur in high-latitude regions near the Earth's magnetic poles. The best known examples are the aurora borealis in the northern hemisphere and the aurora australis in the southern hemisphere. They result from interactions between charged particles emitted by the Sun and the Earth's magnetosphere and atmosphere.

When these particles collide with atmospheric gases, energy is released as light. Most emissions come from oxygen and nitrogen atoms and molecules at altitudes between about 80 and 600 kilometers. The green color at around 557.7 nanometers is the most common, produced by excited oxygen; red light at higher altitudes comes from the same atom, while blue and purple hues arise from nitrogen.

Geographically, auroras form a polar oval around each magnetic pole. During periods of strong solar activity, they can extend toward middle latitudes or be visible at night from lower latitudes. They are most noticeable under dark, clear skies, typically in local winter when nights are long.

Patterns range from curtains and arcs to crescents and diffuse glows, often shifting rapidly and taking on shapes that resemble draperies or solar wind streams along magnetic field lines. The phenomenon is commonly described as dynamic and can vary from faint to intense.

From a scientific perspective, polarlichtern are a key example of space weather and magnetosphere–ionosphere coupling. They have cultural and historical significance in many Arctic and Antarctic communities and are a popular subject for tourism and scientific observation.