Unit 2: Asteroids, Comets, Meteors

Vocabulary flashcards covering asteroids, meteors, comets, and related concepts from the lecture notes.

Asteroid

A rocky, metallic object that orbits the Sun, mainly in the Asteroid Belt between Mars and Jupiter; also called a planetoid or minor planet.

Asteroid Belt

The region between Mars and Jupiter containing about 40,000 asteroids; thought to be material that never formed into a planet; Jupiter's gravity helps keep asteroids from crossing into the inner solar system.

Meteoroid

A small fragment broken from an asteroid.

Meteor

A meteoroid that enters Earth’s atmosphere and is seen as a shooting star.

Meteorite

A meteor that survives passage through the atmosphere and lands on Earth’s surface.

Comet

A rocky, icy, dusty celestial body that orbits the Sun; has a nucleus, coma, and tail and is often described as a dirty snowball.

Nucleus

The solid core of a comet.

Coma

The blob of gas surrounding a comet’s nucleus.

Tail

The glowing stream of gas and dust that extends from a comet, pushed away from the Sun by solar wind.

Kuiper Belt

A region beyond Neptune where many comets originate; orbits the Sun.

Halley’s Comet

A famous comet named after Sir Edwin Halley; it has an average orbital period of about 76 years, with gravity from the major planets altering its revolution.

Dirty Snowball

A colloquial description of a comet, highlighting its icy, dusty composition.