There’s no better conversation starter than the auroral displays that frequent earth’s polar regions. They’re as beautiful as any priceless work of art, and like all great art, they have something to tell us.
The convection of molten metals in the earth’s core works like a generator, producing a powerful magnetic field - the earth's magnetosphere. This magnetic field envelops the earth like an invisible shield, preventing charged particles from the sun - the solar wind - from harming living things here on the earth’s surface.
How do we know this? It’s happening all the time, and most of the time we can’t see it. But when a strong blast of solar wind finds its way into the dips in magnetic energy near the earth’s poles, the resulting interaction between charged particles, earth’s atmosphere, and the magnetosphere can turn the upper atmosphere into one gargantuan ‘neon sign’. The rippling motion of the light exposes lines of magnetic flux, the natural flow of the magnetosphere. The colors reveal gases that are prevalent at various altitudes - green for oxygen, blue and red for nitrogen.
And the show itself? It serves as a reminder that our relationship with the sun is complicated, and goes way beyond a fantastic day at the beach.
Science link: https://sos.noaa.gov/datasets/aurora/