tic field, which is the area around a magnet that has magnetic forces. In physics, force is defined as any action that changes the location, shape, or speed of an object. A magnet has two opposite poles created by magnetic forces going in opposite directions. These are called the north pole and the south pole. Earth is a big magnet and is surrounded by a magnetic field with the North Pole at the top of Earth and the South Pole at the bottom. Scientists think the molten metal in Earth's outer core swirls and creates a magnetic field that extends out into space. The magnetosphere is formed when light energy from the Sun hits Earth's magnetic field. The magnetosphere helps keep Earth from getting too much light energy from the Sun.