Stunning Aurora Substorm Captured by Stargazers
Northern Lights brighten the night sky during spectacular geomagnetic events. Many planets, including Earth, have a magnetosphere—a vast magnetic shield created by the molten metal core's movement that extends far into space.
This magnetosphere protects Earth from harmful charged particles by absorbing their energy upon collision. When parts of the magnetosphere overload with energy, a geomagnetic storm can occur, resembling the buildup of thunderclouds before a storm.
How Geomagnetic Storms Create Auroras
During these storms, accumulated energy travels down Earth’s magnetic field lines and enters the atmosphere like a heavy rainstorm. This influx injects millions of amps into the atmosphere, producing dramatic auroral displays visible far from the poles.
Solar Activity and Coronal Mass Ejections
Occasionally, the Sun releases large bursts of solar material through explosive events known as coronal mass ejections (CMEs). These appear as massive blobs flying through space, impacting Earth's magnetosphere and triggering auroras.
Aurora Colors and Their Origins
- Green auroras, the most common, arise when electrons excite oxygen gas at altitudes between 100–200 km.
- Blue auroras happen when nitrogen gas is excited at similar altitudes (100–200 km).
- Below 100 km, excited nitrogen causes reddish-purple or pink glows.
"Aurora colors result from energetic particles colliding with gases in the upper atmosphere, with each gas producing distinct colors at different altitudes."
The interplay of solar activity, Earth's magnetic shield, and atmospheric gases creates the breathtaking displays that captivate stargazers worldwide.
Author's summary: Earth's magnetosphere, energized by solar activity, funnels charged particles into the atmosphere, creating vivid auroras with colors that depend on the type and altitude of atmospheric gases.