The Northern & Southern Lights (Auroras)

The Northern & Southern Lights (Auroras)

Part 1: What Are They? 🌎

The Northern Lights (Aurora Borealis) and Southern Lights (Aurora Australis) are beautiful, colorful lights that dance across the night sky near the North and South Poles. 

They look like glowing green, pink, or purple curtains or ribbons. They are not stars, planets, or meteors—they are a light show that happens inside Earth's own atmosphere.

Upper Image: A brilliant stream of the southern lights or aurora australis is photographed from the International Space Station as it orbits 270 miles above the Indian Ocean near Antarctica on August 17, 2022.

NASA/Bob Hines

Part 2: Where Does The Power Come From? The Sun! 🌞

The energy for the light show starts 93 million miles away at our Sun.

The Sun's "Wind": The Sun constantly blows out a stream of tiny, invisible particles called the solar wind. Think of it like an invisible energy wind made of electricity.

A Stormy Sun: Sometimes the Sun has big storms (called solar storms). During these storms, it sends out extra-strong bursts of solar wind toward Earth.

Part 3: Earth's Force Field: The Magnetic Shield

Earth has an invisible protective force field called the magnetosphere. It's made by Earth's magnetic core, like a giant magnet inside our planet.

Here’s what happens when the solar wind hits Earth:

• Most of the solar wind particles bounce off this shield.
• But some particles get caught by the magnetic field lines.
• These magnetic field lines act like slides or funnels, guiding the particles down to the North and South Poles.

Particles from solar eruptions bombard Earth’s magnetic field and enter the atmosphere at regions called auroral ovals. These particles interact with gases in the atmosphere, creating auroras.

Tromsø Geophysical Observatory, UIT the Arctic University of Norway

Key Idea: This is why auroras usually only happen near the Arctic and Antarctic!

Part 4: Making The Colors: The "Sky Paint"

The real magic happens when the solar particles reach Earth's upper atmosphere.

• The "Paint" (Air Gases): Our air is made of gases, mainly oxygen and nitrogen.
• The Crash (Collision): The high-energy solar particles crash into these oxygen and nitrogen atoms like tiny bumper cars.
• The Glow (Light Emission): When they crash, they transfer energy. The air atoms get "excited" and then almost instantly calm down by releasing that extra energy as light.

Trillions of these tiny crashes happening at once create the glowing curtains we see.

The Color Code:

• Green & Red: Comes from collisions with oxygen atoms.
• Purple & Pink: Comes from collisions with nitrogen atoms.

Part 5: Why Do They Move and Change?

• The Solar Wind is Like a River: The solar wind isn't steady. Its speed and strength change, which makes the lights sway, ripple, and dance.
• Big Solar Storms = Bigger Shows: When the Sun sends a powerful storm (a Coronal Mass Ejection), it pushes Earth's magnetic shield harder.
• This lets the solar particles reach farther from the poles.
• Result: People in places like the northern United States or Europe can sometimes see the aurora during these big storms!

The Full Story - Simple Summary

• Sun sends out particles (solar wind).
• Earth's Magnetic Field catches and guides particles to the poles.
• Particles Crash into air gases (oxygen & nitrogen).
• The Crash Makes Light! (Green, red, purple, pink).
• We see the beautiful Aurora.

Final Thought: 

The aurora is more than just pretty lights. It’s a sign of our planet protecting us from space weather, and it shows the amazing connection between the Earth and the Sun.