Astronomy Vocabulary List 2 & 3

Solar System

our sun and the planets that move around it

Rotation

one complete turn of the Earth on its axis (24 hours)

Axis

the imaginary line through the center of the Earth

Revolution

the circular movement of the Earth around the sun

Orbit

the curved path of the Earth around the sun

Constellations

a group of stars that forms a particular shape in the sky and has been given a name

Asteroids

any one of thousands of small rocky bodies that circle around the sun

Comets

an object in outer space that develops a long, bright tail when it passes near the sun

Corona

The crown of gases around the sun.

Eclipse

When our view of one object in the sky is blocked by another object or the Earth's shadow.

Equinox

March 20th or 21st and September 21st or 22nd. Twice a year when the day and night are the same amount of time all around the world.

Galaxy

A group of stars, gas and dust held together by gravity.

Local Group

A group of around two dozen galaxies.

Milky Way

The name of our galaxy (the galaxy that our solar system is in).

Planet

An object moving around a star.

Solstice

The 21st or 22nd of June, and 21st or 22nd of December. Time of the year when the day is either shortest, or longest depending on where you are.

Star

An object that shines through the release of energy produced by nuclear reactions at its core.

Sun spots

Dark patches on the Sun's surface.