Stunning Aurora Substorm Captured by Stargazers
Many planets, including Earth, have a magnetosphere—a vast magnetic shield formed by the molten metal core's movement, extending far into space. Earth's magnetosphere defends the planet by absorbing energy from harmful charged particles when they collide with it.
When parts of the magnetosphere become saturated with energy, a geomagnetic storm can develop, similar to how storm clouds gather before rain. During such storms, this stored energy flows along Earth's magnetic field lines into the atmosphere, resembling a heavy downpour.
The particle influx during geomagnetic storms injects millions of amps into the atmosphere, producing spectacular auroral displays visible far from the poles.
Solar Origins of Auroras
Occasionally, magnetic storms on the Sun release enormous amounts of solar material through explosive events known as coronal mass ejections (CMEs). These massive blobs travel through space and influence space weather around Earth.
Colors of the Aurora
Aurora colors originate from energetic particles colliding with atmospheric gases, with each gas producing unique colors at various altitudes:
- Green auroras, the most common, occur when electrons excite oxygen gas at altitudes between 100 and 200 km.
- Blue auroras appear when nitrogen gas is excited at similar altitudes (100–200 km).
- At altitudes below 100 km, nitrogen produces reddish-purple or pink glows.
"Northern Lights to brighten your doomscroll 🌃"
Author's summary: Earth's magnetosphere shields us from charged particles, and when overloaded, it sparks geomagnetic storms that create breathtaking auroras with distinct colors based on atmospheric gases and altitude.