Unit 3 Astronomy Vocabulary Review

This is a galaxy with a characteristic pinwheel shape with a flat disk, central bulge, and graceful arms containing regions where young stars form.

This is a galaxy consisting of mostly older stars that has no dust lane and is fairly featureless. The shape can range from spherical to highly elongated.

This is a galaxy that does not have a regular shape, like a spiral or an elliptical galaxy. The shape of one of these is uncommon and often were once spiral or elliptical galaxies and were deformed by gravitational action.

The distance light travels in one year

A large spiral galaxy that is home to Earth and the rest of our solar system, and about a trillion stars.

This is the period of time it takes for earth to make a complete rotation on its axis; 24 hours

This is the period of time it takes for earth to make a complete revolution (a full orbit) around the sun; consists of 365 days, 5 hours, 49 minutes, and 12 seconds

Describe the motion that occurs when the Moon rotates on its axis and revolves around the Earth.

This is the appearance of the illuminated (sunlit) portion of the Moon as seen by an observer, usually on Earth.

This is a natural satellite that orbits a planet or smaller body, which is called the primary.

A small, rocky object that orbits the Sun

A small, rocky and icy object that orbits the Sun

A meteoroid that has entered Earth's atmosphere and produces a streak of light

An instrument that separates visible light into its various wavelengths.

An imaginary line that passes through Earth's center and the North and South poles, about which Earth rotates