Unit 8 Science Summative | The Solar System and the Universe

Meteor

A small space rock that may enter Earth's atmosphere

Celestial Body

A natural object in space like a star, planet, moon, asteroid, or comet.

Atmosphere

A layer of gases surrounding a planet.

Meteoroid

A small space rock that floats in space

Asteroid

A small rocky object orbiting the Sun, mostly found in the asteroid belt.

Solar System

The Sun and everything orbiting it, including planets, moons, asteroids, and comets.

Big Bang Theory

The scientific theory that the universe began from a small, hot, dense point and has been expanding.

Inertia

The tendency of an object to resist a change in motion.

Milky Way

The galaxy containing our solar system.

Comet

An icy body that develops a tail when near the Sun.

Elliptical Orbit

The curved oval path of a celestial object around a star, planet, or moon.

Geocentric

A model where the Earth is at the center of the universe.

Heliocentric

A model where the Sun is at the center of the solar system.

Gravity

The force that attracts two bodies toward one another.

Galaxy

A system of stars, gas, and dust bound together by gravity.

Planet

A celestial body moving in an elliptical orbit around a star

Asteroid Belt

Space between Jupiter and Mars contains many asteroids.

Terrestrial Planet

A planet composed of rocks or metals.

Astronomical Unit

The distance from the center of the Sun to the center of the Earth

Universe

All existing matter and space; the cosmos

Kuiper Belt

Ring of icy bodies just outside of Neptune's orbit.

Oort Cloud

A spherical cloud of small rocky and icy bodies beyond the orbit of Pluto.

Gaseous Planets

Giant planet composed of gas, mainly hydrogen and helium

Tail

A long, bright stream of gas and dust that extends from a comet.