Meteorites are solid fragments of meteoroids that survive their journey through the Earth's atmosphere and land on the surface. They can vary in size, from tiny grains to large boulders, and are primarily composed of rock, metal, or a combination of both. When a meteoroid enters the atmosphere, it creates a bright streak of light known as a meteor or "shooting star" before it potentially reaches the ground. Scientists study meteorites to learn more about the early solar system and the formation of planets. These space rocks can provide valuable information about the composition of asteroids and other celestial bodies, helping researchers understand the history of our universe.