Aurora borealis green sky

The aurora borealis, a natural phenomenon that paints the sky green, occurs when solar particles collide with Earth's atmosphere.

About this subject

The aurora borealis, or northern lights, is a visual display caused by the interaction between solar wind and Earth's magnetic field. Charged particles from the Sun excite oxygen and nitrogen atoms in the atmosphere, releasing energy as light. Green is the most common color, produced by oxygen at altitudes between 100 and 250 km. The phenomenon is most frequent in polar regions, within the Auroral Oval that surrounds the magnetic poles.

Prime viewing locations include Norway, Sweden, Finland, Iceland, Canada, and Alaska, during winter months (September to March) when nights are longest and darkest. Solar activity follows an approximately 11-year cycle, with peaks of higher intensity, such as the one expected for 2024-2025, increasing chances of sightings even at lower latitudes.

Culturally, the aurora borealis has inspired mythologies among Nordic and Inuit peoples. Vikings associated it with gods, while the Sami believed it was the energy of departed souls. In modern science, studying auroras helps understand space weather and its effects on satellites and power grids. Travel photographers seek to capture the phenomenon with long exposures, revealing details invisible to the naked eye.

Frequently Asked Questions

What causes the aurora borealis?

The aurora borealis is caused by collisions between charged particles from the solar wind and atoms in Earth's atmosphere, exciting them and emitting light. Earth's magnetic field guides these particles toward the poles.

What is the best time to see the northern lights?

The best time is during winter, from September to March, when nights are long and dark. Solar activity peaks in an 11-year cycle; the next peak is expected in 2024-2025.

Can the aurora borealis be seen from Brazil?

It is extremely rare, but during very intense solar storms, auroras can be seen at lower latitudes. In Brazil, there are historical records, such as in 1859 and 1989, but these are exceptional events.