Why in news?
A strong geomagnetic storm in early June 2026 produced spectacular auroras that were visible at higher latitudes and, for brief moments, as far south as the Himalayas. Social media was flooded with photos of the colourful lights, rekindling interest in how they form.
Background
The aurora borealis, or “northern lights,” is a natural light display that occurs when charged particles from the Sun interact with Earth’s magnetic field and atmosphere. The solar wind carries a stream of electrons and protons that sometimes collide with Earth’s magnetosphere. When these particles are funnelled along magnetic field lines into the upper atmosphere, they excite oxygen and nitrogen atoms, causing them to emit photons.
Formation and colours
- Solar wind and magnetosphere: The Sun constantly emits a flow of charged particles called the solar wind. When solar storms occur, this flow intensifies and compresses Earth’s magnetosphere, enabling more particles to enter.
- Excitation of atmospheric gases: At altitudes of 60–200 km, energetic particles collide with oxygen molecules, which emit green light. At higher altitudes above 120 km, excited oxygen can also emit red light. Nitrogen molecules produce blue and pink hues, especially at lower altitudes.
- Latitude and visibility: Auroras are usually restricted to high latitudes near the poles because Earth’s magnetic field guides particles there. During intense geomagnetic storms, however, the auroral oval expands, allowing people at mid‑latitudes — even parts of northern India — to glimpse the display.
Significance
Auroras are beautiful reminders of our planet’s connection to the Sun. They also serve as indicators of space weather, which can disrupt satellites, navigation systems and power grids. Understanding auroras helps scientists monitor geomagnetic storms and protect technological infrastructure.
Conclusion
The June 2026 aurora event captivated sky‑watchers and highlighted the dynamic interaction between the Sun and Earth. Continued observations and public education about space weather will help communities prepare for future geomagnetic storms.
Source: The Hindu