Earth's Magnetic Field

Imagine a big, cozy hug that wraps all the way around the world. You can’t see me or touch me, but I am always there, like a warm, invisible blanket. I keep everyone safe from the sun's super-fast windy bits that try to visit. I am a secret helper for our whole planet. Sometimes, I like to play with little pointers on a compass. I make them wiggle and dance and wiggle some more until they point to the chilly north. It's my favorite game to play, showing everyone which way to go.

A long, long, long time ago, around the 2nd century BCE in a place called China, some very clever people found special rocks. These rocks were called lodestones. When they held a tiny piece of the rock, they saw me make it point north. It was our little secret. They used my secret to make the very first compasses. Those compasses helped sailors find their way across the big, big blue oceans on their boats, so they never got lost. Much, much later, in the year 1600, a curious man named William Gilbert had a big idea. He realized that I wasn't just in the rocks. He told everyone that the whole Earth was like one giant magnet, and I was its magical power.

So who am I. I am Earth's Magnetic Field. I am still working hard every single day to keep you safe. When the sun’s windy bits bump into me, I don't let them through. Instead, I use them to paint beautiful, colorful lights in the night sky. People call them the auroras, and they dance with green and pink colors. I also help birds and big sea turtles find their way home when they go on long, long trips. I will always be here, protecting you and showing the way, like your planet's invisible superhero shield.