A meteorite is a solid fragment of a meteoroid that survives its journey through the Earth's atmosphere and lands on the surface. When a meteoroid enters the atmosphere, it heats up and creates a bright streak of light known as a meteor or "shooting star." If it makes it to the ground, it is called a meteorite. Meteorites can vary in size, from tiny grains to large boulders, and they provide valuable information about the early solar system. Scientists study meteorites to learn more about the formation of planets and the materials that make up celestial bodies like the Moon and Mars.