Meteoroids are small rocky or metallic bodies that travel through space. They are significantly smaller than asteroids, typically ranging in size from a grain of sand to a few meters across. When a meteoroid enters the Earth's atmosphere, it heats up due to friction and creates a bright streak of light known as a meteor. If a meteoroid survives its fiery journey and lands on the Earth's surface, it is called a meteorite. These space rocks can provide valuable information about the early solar system and the formation of planets, making them important for scientific research and exploration.