Y8 - Galaxies & Light Years

A galaxy is a system of millions, billions or trillions of _ _ _ _, along with gas and dust, held together by _ _ _ _ _ _ _.

The four main types of galaxies are: S _ _ _ _ _, B _ _ _ _ _ S _ _ _ _ _, E _ _ _ _ _ _ _ _ _ & I _ _ _ _ _ _ _ _.

There are more stars in the universe than grains of sand on earth.

• True

• False

What is the closest galaxy to the Milky Way?

• Proxima Centauri

• Spiral

• Andromeda

• Elliptical

A light year is the _ _ _ _ _ _ _ _ travelled by _ _ _ _ _ in one Earth _ _ _ _.

A light year is a measure of time.

• True

• False

Why do we use light years?

• Scientists are lazy.

• To make large numbers more manageable.

• So we can time travel.

• So we can make objects that are far away closer.

Why is seeing faraway galaxies in the past useful to scientists?

• They can study life in other galaxies.

• They can test their telescopes.

• They can study galaxies in their infancy.

• They can test their time machines.

Why are we currently unable to travel to celestial bodies outside of our Solar System?

• We don't know what is beyond our Solar System.

• Scientists & astronauts don't want to go.

• It would take longer than a human lifespan to reach.