The main responsabile for these stunning light shows is our beloved star, the Sun.
"Our sun is 93 million miles away. But its effects extend far beyond its visible surface. Great storms on the sun send gusts of charged solar particles hurtling across space. If Earth is in the path of the particle stream, our planet’s magnetic field and atmosphere react." - Earth Sky.org
Through heat and light, the Sun constantly expells an incredibile amount of charged particles towards the Earth, but it doesn't send the same amount of energy all the time. One could say there is a constant streaming of Solar Wind and there are also Solar Storms, but more on that later.
"The Earth has a magnetic field surrounding it because of the iron-nickel core at the center of our planet. The magnetic field exiting from the core is responsible for the magnetic north and south poles we use when we navigate with a compass. It also creates a magnetic force field around the Earth, which extends into space." - Science Connected.org
So, as Earth travels through Space, so does its magnetic field, which surrounds us, forming an invisible shield against radiation and Solar flares. As you can see from the artistic photo above, the field is compressed by the solar wind on the bright side of the Earth, while on the night side of the planet, the field stretches away from our position like a beautiful comet's tail.
However, the field is not completely sealed. When a solar particles comes toward us, some of that plasma can sneak in through the north and south poles into Earth's atmosphere, getting trapped on the magnetic pull of the magnetic field lines.
At any given time, the movement of charged particles in Earth’s magnetic field produces powerful electric currents.
When these trapped "space particles" hit the molecules suspended in Earth’s atmosphere (which are electrically charged due to the Earth's own motion), they trigger the light displays we called Aurora, resulting on different colour bursts, depending on the altitude, speed and amount of energy involved in the collision.
"Most of the molecules in Earth’s atmosphere are either nitrogen or oxygen, so they are hit most frequently. Colors produced may be pink, red, yellow, green, blue, or violet. Occasionally, orange or white are produced. Typically, nitrogen will produce red, violet, or blue. Oxygen usually produces green or yellow." - Science Connected.org
As you can probaly imagine, as Science gets a better grip on the real origin and mechanics behind this fantastic phenomena, it can be hard to keep up and grasp the idea.imagini
Fairytales aside, we always find joy in imagining these invisible particles being lit up as they surf Earth's magnetic fields, like plasma moving along a wavy and dinamic highway, stretching through thousands of kilometers above our heads, leaving some astonishing fireworks on its path through Space, dancing playfully.