Meteoroid
A meteoroid is a small rocky or metallic body traveling through space, usually within our Solar System. These objects range in size from tiny grains to about a meter in diameter. They originate mostly from asteroids, comets, or debris left over from the formation of planets.
The concept of meteoroids developed gradually as astronomers studied the sources of shooting stars. The term "meteoroid" was coined by American astronomer Fred Whipple in 1951 to describe these small space rocks distinct from larger asteroids and smaller dust particles.
Meteoroids are important because they are remnants of the early Solar System, offering clues about its formation and evolution. Modern space missions such as OSIRIS-REx and Hayabusa have brought back samples from asteroids, which are closely related to meteoroids, helping scientists study their composition.
Meteor
A meteor is the visible streak of light produced when a meteoroid enters Earth’s atmosphere at high speed and vaporizes due to friction with the air. This phenomenon is often called a "shooting star," although it’s not a star at all.
The light emission happens because the meteoroid’s surface heats up and ionizes, creating a glowing trail that can last from a fraction of a second to several seconds. Sometimes meteors can be very bright, called fireballs or bolides, and may even explode mid-air.
The understanding of meteors dates back centuries, but the scientific explanation for their origin came in the late 19th century. The Hungarian astronomer Denis Képler (not to be confused with Johannes Kepler) and others made early observations, but it was the British astronomer Richard A. Proctor in the 1860s who helped popularize the idea that meteors are caused by small particles entering Earth’s atmosphere.
Today, networks of cameras and radars track meteors globally, providing data to study meteor showers and atmospheric physics.
Meteorite
A meteorite is a fragment of a meteoroid that survives its fiery passage through the atmosphere and lands on Earth’s surface. These fragments vary in size from tiny grains to large masses weighing several tons.
Meteorites are classified mainly into stony, iron, and stony-iron types, depending on their composition. They often have a melted outer crust called a fusion crust formed during atmospheric entry.
Historically, meteorites were often misunderstood or dismissed as strange rocks. The first well-documented recognition of meteorites as extraterrestrial objects came in the early 19th century. The French scientist Jean-Baptiste Biot conducted a scientific investigation of the L’Aigle meteorite fall in 1803, proving to the scientific community that stones can indeed fall from the sky.
Meteorites are invaluable to science because they are physical samples of other celestial bodies, including asteroids, the Moon, and Mars. Modern analysis using advanced technologies such as mass spectrometry allows scientists to date the Solar System and study its early chemistry.