Imagine there’s an invisible force field around our planet. Now imagine that for billions of years, that force field has been protecting us from a beam of supercharged plasma that would otherwise wipe out life on Earth as we know it. You might think this is some kind of science fiction story, but it’s all true. And it’s what gives us this: The aurora!
From PBS’ Digital Studios, It’s Okay to Be Smart‘s The Science and Beauty of Auroras. Learn More about the invisible forcefield — a magnetic field — that protects all life on Earth from space radiation, primarily Sun’s solar winds that bombard our atmosphere constantly. More from IOTBS host Joe Hanson:
…the edge of the Sun, the corona, is a busy, beautiful place, full of churning whirlpools of plasma and huge magnetic arcs. All of that action is constantly releasing waves of energized particles, creating what we call the “solar wind”…
When those energized particles smash into gases way up high in our atmosphere, they “excite” them, which means the gas atoms grab on to a bit of energy. But they don’t stay excited for long. They give off that stored energy in a bright little burst of light. Different atoms in our atmosphere each give off different colors.
Excited oxygen is what gives off that familiar green and red that most of us think of when we hear “aurora”. But there’s also nitrogen up there, and it can give off a really cool mix of red and blue light that makes the sky glow this incredible purplish-pink. Now, we can only see this happening at night, but it’s happening 24 hours a day, every day of every year!