Unit 11.0 :Galaxy

What is a galaxy?

• A group of planets orbiting the Sun
• A system consisting of millions of stars, gas, dust, and other matter bound together by gravity
• A group of black holes
• A group of artificial satellites

Answer explanation

A galaxy contains millions of stars, gas, dust and matter held together by gravity. (p.180)

The Milky Way Galaxy is shaped like a …

• Ellipse
• Barred spiral
• Perfect circle
• Irregular shape

Answer explanation

The Milky Way is a barred spiral galaxy. (p.184)

The Solar System is part of …

• Andromeda Galaxy
• Triangulum Galaxy
• The Milky Way Galaxy
• The Magellanic Clouds

Answer explanation

Our Solar System is located in the Milky Way Galaxy. (p.184)

The location of the Solar System in the Milky Way Galaxy is …

• At the galactic centre
• At the edge of one of the spiral arms
• Outside the galaxy
• Between two galaxies

Answer explanation

The Solar System is at the edge of one spiral arm in the Milky Way. (p.185)

Why can we only see part of the Milky Way Galaxy from Earth?

• Earth is surrounded by thick nebulae
• Earth is located at the edge of the galaxy
• The Sun is too dim
• The galaxy changes shape every night

Answer explanation

Earth's location at the edge of the galaxy limits our view. (p.185)

The name “Milky Way” refers to …

• A rainbow-coloured streak
• Spilled milk in the night sky (ancient Roman analogy)
• A joke by astronomers
• A Greek scientist’s name

Answer explanation

The name comes from its milky appearance, like spilled milk. (p.184)

The Solar System consists of the Sun, Earth, and …

• Six other planets
• Seven other planets
• Eight other planets
• Nine other planets

Answer explanation

The Solar System includes the Sun, Earth, and seven other planets. (p.184)

What do the thousands of tiny dots in the Hubble image represent?

• Nebulae
• Comets
• Galaxies
• Asteroids

Answer explanation

The dots are distant galaxies captured in the Hubble image. (p.181)

Size analogy: If the Solar System is compared to the diameter of a pencil, then the Milky Way Galaxy is compared to …

• A textbook
• A classroom
• A school field
• A football

Answer explanation

The Milky Way is enormously larger, like a school field compared to a pencil. (p.187)

The stars in a galaxy orbit around the …

• Earth
• Sun
• Galactic centre
• Magellanic Clouds

Answer explanation

Stars orbit around the galactic centre. (p.180)