Galaxies are classified by shape into elliptical, spiral, or irregular. Spiral galaxies have a central bulge and spiral arms, with older stars in the bulge. The Milky Way is a barred spiral galaxy. Elliptical galaxies lack structure, contain old stars, and have little gas or dust. Irregular galaxies lack a defined shape, often due to gravitational interactions with other galaxies.

What are the three main types of galaxies based on their shapes?

• Elliptical, Spiral, Irregular

• Circular, Spiral, Irregular

• Spiral, Circular, Elliptical

• Elliptical, Circular, Irregular

What does the shape of a galaxy indicate?

• The distance from Earth

• The age and types of stars within the galaxy

• The speed of the galaxy

• The size of the galaxy

Which type of galaxy has a central bulge of stars surrounded by a disk with spiral arms?

• Irregular

• Elliptical

• Barred Spiral

• Spiral

What is an example of a spiral galaxy?

• The Milky Way

• The Andromeda Galaxy

• The Large Magellanic Cloud

• The Triangulum Galaxy

Tags

NGSS.MS-ESS1-2

What distinguishes barred spiral galaxies from regular spiral galaxies?

• They have a bar of stars across the middle

• They are larger in size

• They have more spiral arms

• They contain younger stars

What percentage of observed spiral galaxies are barred spiral galaxies?

• About 3/4

• About 2/3

• About 1/3

• About 1/2

What is the shape of elliptical galaxies?

• Flat and disk-like

• Irregular and undefined

• Smooth and ellipsoidal

• Barred and spiral

What is a characteristic of stars in elliptical galaxies?

• They are mostly old and red

• They are evenly distributed

• They are mostly in the outer regions

• They are mostly young and blue

What would be the effect on Earth if it were inside an elliptical galaxy?

• There would be more meteor showers

• It would be colder

• There would be no day and night

• It would be dark all the time

Tags

NGSS.MS-PS2-4

What likely causes the irregular shape of irregular galaxies?

• Their young age

• Disruption by neighboring galaxies

• Their high speed

• Their large size