Imagine a giant needle passing through the Earth from top to bottom. This is the Axis. Earth doesn't sit straight up; it leans at an angle of 23.5 degrees.
Scientists believe a massive object called Theia crashed into Earth billions of years ago, knocking our planet sideways and actually creating our Moon!
Because the Earth is a sphere, the Sun can only light up half of it at a time. As we rotate from West to East, we move in and out of this sunlight.
Since Earth rotates 360 degrees in 24 hours, it moves 15 degrees every hour. This is why when it is morning in Addis Ababa, it might still be night in New York!