Space and Astronomy Vocabulary

A collection of vocabulary flashcards based on lecture notes regarding celestial bodies, gravitational laws, and solar system models.

Asteroid

One of the rocky objects revolving around the sun that is too small and numerous to be considered a planet.

Astronomical Unit

A unit of distance equal to the average distance between Earth and the sun, about $150\text{ million kilometers}$.

Axis

An imaginary line that passes through a planet's center and its north and south poles, about which the planet rotates.

Comet

A loose collection of ice and dust that orbits the sun, typically in a long, narrow orbit.

Constellation

A pattern or grouping of stars that people imagine to represent a figure or object.

Eclipse

The partial or total blocking of one object in space by another.

Ellipse

An oval shape, which may be elongated or nearly circular; the shape of the planets' orbits.

Equinox

Either of the two days of the year on which neither hemisphere is tilted toward or away from the sun.

Geocentric

Term describing a model of the universe in which Earth is at the center of the revolving planets and stars.

Gravity

The attractive force between objects; the force that moves objects downhill.

Heliocentric

Term describing a model of the solar system in which Earth and the other planets revolve around the sun.

Inertia

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

Law of Universal Gravitation

The scientific law that states that every object in the universe attracts every other object.

Meteor

A streak of light in the sky produced by the burning of a meteoroid in Earth's atmosphere.

Meteoroid

A chunk of rock or dust in space, generally smaller than an asteroid.

Moon

A natural satellite that orbits a planet.

Neap Tide

The tide with the least difference between consecutive low and high tides.

Orbit

The path of an object as it revolves around another object in space.

Penumbra

The part of a shadow surrounding the darkest part.

Phase

One of the different shapes of the moon as seen from Earth.

Planet

An object that orbits a star, is large enough to have become rounded by its own gravity, and has cleared the area of its orbit.

Revolution

The movement of an object around another object.

Rotation

The spinning motion of a planet on its axis.

Satellite

1. An object that orbits a planet. 2. Any object that orbits around another object in space.

Solar System

The system consisting of the sun and the planets and other objects that revolve around it.

Solstice

Either of the two days of the year on which the sun reaches its greatest distance from the equator.

Spring Tide

The tide with the greatest difference between consecutive low and high tides.

Star

A ball of hot gas, primarily hydrogen and helium, that undergoes nuclear fusion.

Sun

A large, gaseous body at the center of the solar system.

Tide

The periodic rise and fall of the level of water in the ocean.

Umbra

The darkest part of a shadow.