Gravity and the Solar System Vocabulary

Practice flashcards covering the key vocabulary and components of the solar system, including gravitational forces and the eight planets.

Gravitational force

An attractive force between all objects that have mass, which pulls them together; its strength depends on mass and distance.

Solar system

A system consisting of a star and all of the celestial objects that travel around it in orbit.

Planet

An object that directly revolves around a star, has a nearly spherical shape, and has cleared the neighborhood around its orbit.

Moon

A celestial object that indirectly revolves around a star by revolving around another celestial body like a planet.

Natural satellite

A celestial body, such as a moon, that revolves around another celestial body and was not created by humans.

Artificial satellite

A human-made object designed to revolve around a planet, such as GPS satellites or the International Space Station.

Dwarf planet

A celestial object that directly revolves around the sun and is nearly round, but has not cleared the neighborhood around its orbit.

Asteroid

A small rocky or metallic object that revolves around the sun, often found between the orbits of Mars and Jupiter.

Comet

A small object made of rock, ice, and dust that revolves around the sun and produces a tail of gas and dust when it travels close to the sun.

Astronomical unit (AU)

A unit of measurement equal to the average distance between Earth and the sun, which is approximately $150 \times 10^6\,\text{km}$.

Scale model

A representation of a system that maintains the same relative sizes or distances as the actual system being modeled.

Mercury

The closest planet to the sun, which can be difficult to see due to the sun's glare and exhibits phases through a telescope.

Venus

The second planet from the sun, extremely bright and named after the Roman goddess of beauty; it also exhibits phases similar to the moon.

Mars

The fourth planet from the sun, named after the Roman god of war because of its distinct reddish or orange color.

Jupiter

The most massive planet in the solar system, which possesses the strongest gravitational forces and the greatest number of moons among the planets.

Saturn

A planet smaller and dimmer than Jupiter, identifiable by its rings when viewed through a telescope.

Uranus

A very dim planet, approximately $12$ times smaller than Saturn (with rings), that usually requires a telescope or binoculars to observe.

Neptune

The farthest planet from the sun and the only one in the solar system that cannot be seen from Earth without the aid of tools like telescopes.

Main asteroid belt

The region in the solar system located between the orbits of Mars and Jupiter where most asteroids are found.