Asteroids and meteors are both categorized based on their physical characteristics and orbital properties. While asteroids are generally larger and orbit the Sun in the asteroid belt between Mars and Jupiter, meteors are smaller and typically result from the fragmentation of asteroids or comets. Here's how scientists classify them:

Asteroids:

1. Size: Asteroids range in size from a few meters to hundreds of kilometers in diameter. Smaller asteroids are sometimes referred to as "minor planets."

2. Composition: Asteroids can be classified based on their composition into three primary types:

- C-type (carbonaceous): Most common, made of carbon-rich material and dark in appearance.

- S-type (silicate): Composed primarily of silicate minerals, appear brighter.

- M-type (metallic): Contain high amounts of metals like iron and nickel.

3. Orbit: Asteroids primarily orbit the Sun in the asteroid belt, although some have orbits that bring them closer to Earth or other planets.

Meteors:

1. Size: Meteors are small particles of dust and rock that range in size from tiny grains to several meters across. They are sometimes called "shooting stars."

2. Origin: Meteors originate from various sources, including fragments of asteroids or comets, or dust left behind by comets.

3. Entry into Earth's Atmosphere: When a meteor enters Earth's atmosphere, it heats up due to friction and becomes a bright streak of light in the sky.

4. Meteorite, Meteoroid, Meteor:

- Meteoroid: A meteoroid is a small piece of debris in space, a fragment of an asteroid or comet.

- Meteor: When a meteoroid enters Earth's atmosphere and begins to glow due to heat and friction, it becomes a meteor or shooting star.

- Meteorite: If a meteoroid or a fragment of a meteor reaches Earth's surface without completely disintegrating, it is called a meteorite.

By studying the properties, orbits, and compositions of asteroids and meteors, scientists gain valuable insights into the formation and evolution of our solar system.