While a meteor itself is the bright streak of light we see in the sky, the objects causing this phenomenon are often made of rock, metal, or sometimes icy material.
Understanding the terms helps clarify:
- Meteoroid: A small natural solid object traveling through space, originating from asteroids, comets, or even planets. Meteoroids vary in size, from tiny dust grains to small boulders.
- Meteor: The visible streak of light created when a meteoroid enters Earth's atmosphere at high speed and burns up due to friction. This is commonly referred to as a "shooting star."
- Meteorite: A meteoroid that survives its fiery passage through the atmosphere and lands on the Earth's surface.
The Composition of Objects Causing Meteors
The material makeup of meteoroids determines their fate as they enter the atmosphere and, consequently, whether they cause a bright meteor or survive to become a meteorite.
Common compositions include:
- Rocky (Stony): These are fragments from asteroids, similar in composition to rocks found on Earth, but often with distinct structures and mineral types. Most meteoroids are rocky.
- Metallic (Iron): Composed primarily of iron and nickel. These also originate from asteroids.
- Stony-Iron: A rarer type containing a mix of rocky and metallic material.
- Icy/Dusty: Fragments broken off from comets. These tend to be less dense and often burn up completely high in the atmosphere, producing short-lived meteors.
What Survives Tells Us About Composition
The fact that meteoroids survive atmospheric entry to become meteorites provides crucial evidence about their composition. As the provided reference states, "Meteorites are rocks". This confirms that many of the objects originally causing meteors are indeed rocky.
However, meteorites are not just any rocks. The reference highlights their unique characteristics:
- They are different from most rocks found on Earth's surface.
- Many are far older than Earth rocks, preserving material from the early solar system.
- They provide some of the only physical samples we have of other worlds – including other planets, asteroids, and possibly comets.
- Some meteorites even contain tiny particles that formed around other stars that existed before our Sun.
So, while a meteor is a fleeting light show, it is caused by a physical object (a meteoroid) which is frequently made of rocky material. The meteorites recovered on the ground serve as tangible proof of the rocky (or metallic) nature of these visitors from space.
| Term | Description | Primary Composition |
|---|---|---|
| Meteoroid | Object in space (before atmospheric entry) | Rock, Metal, or Ice/Dust |
| Meteor | Streak of light (during atmospheric entry) | Phenomenon (caused by Meteoroid) |
| Meteorite | Object that lands on Earth (after atmospheric entry) | Rock or Metal (surviving material) |
