The Solar System

Solar system

A gravitationally bound system consisting of a sun and the objects that orbit it.

Galaxy

A huge collection of gas, dust, and billions of stars and their solar systems held together by gravity.

Orbit

A regular, repeating path that one object in space takes around another one.

Universe

All of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy.

Planet

An astronomical body that orbits a star, is big enough to have enough gravity to force a spherical shape, and is big enough that its gravity has cleared away any objects of a similar size near its orbit

Gravity

An attractive force between two masses by which a planet or other body draws objects toward its center.

Habitable zone

The orbital region around a star in which an Earth-like planet can possess liquid water on its surface and possibly support life

Kuiper belt

A large region in the solar system past Neptune where Pluto and other dwarf planets orbit the Sun along with rocks, dust, and ice.

Asteroid belt

A region in the solar system roughly located between the orbits of the planets Jupiter and Mars that contains millions of irregularly shaped pieces of rock (called asteroids) as well as ice and dust.

Scale model

A three-dimensional representation of an object or system that maintains accurate relationships between the components of the model such as size and distance.