Magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by the object’s magnetic field. The magnetosphere of Earth extends from the surface of the planet outwards about 65,000 kilometers (40,400 miles), to where it meets the solar wind flowing from the Sun. Charged particles in the solar wind are deflected around Earth by its magnetosphere.
The size and shape of Earth’s magnetosphere are constantly changing in response to changes in the solar wind. When the solar wind is strong, it compressess the magnetosphere on the side facing away from the Sun. This compression can cause auroras, or northern and southern lights, as charged particles from inside Earth’s magnetosphere collide with atoms in Earth’s upper atmosphere.