Universe

Rank the following from smallest to largest

• Star cluster

• Star system

• Galaxy

• Solar system

• Universe

Answer explanation

The universe contains all the matter and energy that has or will ever exist, including an estimated billions of galaxies. Solar systems refer to a single star with its satellites compared to star systems (with as few as two stars) and star clusters (at least tens of stars).

Let's take a trip to outer space! Can you tell me what galaxies are made of? Choose the best answer!

• Just stars

• Stars and gas

• Stars, dust, and gas

• Stars, dust, and gas all held together by gravity

Imagine you're an astronaut exploring the universe and you come across a galaxy. It's flat, disk-shaped, with a central bulge and winding "arms" that extend outward. What type of galaxy have you discovered?

• An irregular galaxy, perhaps?

• Could it be a spiral galaxy?

• Is it an elliptical galaxy?

• Or is it some random galaxy?

Can you guess the type of galaxy we're exploring today?

• Spiral

• Elliptical

• Irregular 

• Irrational

Imagine you're on a spaceship, zooming through the cosmos at the speed of light. You come across a galaxy that's a whopping one billion light years away from our home, Earth. What fascinating fact can you deduce from this?

• We're actually seeing the galaxy as it appeared one billion years ago. Time travel, anyone?

• We're seeing the galaxy as it was when the universe was just a baby, only one billion years old.

• We're getting a sneak peek at how the galaxy will look in one billion years. Talk about future vision!

• We're seeing a preview of what our own galaxy, the Milky Way, will look like in one billion years. Isn't that mind-blowing?

Imagine you're an astronaut, floating in the vast expanse of space. You notice that most galaxies are zooming away from you! According to Hubble's Law, this speed is proportional to their...

• size - like how bigger rockets move faster, right?

• mass - because heavier things are always faster, aren't they?

• quasars - those bright, distant objects must have something to do with it, right?

• distance - the further they are, the faster they move. Could this be it?

Imagine you're a cosmic detective! You've come across a mysterious entity made of lots of gas and dust.

It's a hotbed for star formation, but it doesn't seem to have any structure.

You've heard rumors that it might be the result of galaxies colliding.

Can you guess what it is?

• Irregular

• Spiral

• Elliptical

Can you guess the name of the galaxy we live in?

• M38

• Milky Way Galaxy

• Andromeda Galaxy

• Pinwheel Galaxy

Let's take a trip to the cosmos! Galaxies are classified based on certain observable characteristics. Can you guess which characteristic we use to categorize them?

• Their unique shapes

• Their temperature

• The types of forces they exhibit

• The chemical elements they contain

Ready for a cosmic journey? Can you tell us what 'red shift' is all about?

• Is it when wavelengths of light stretch out because the object emitting light is zooming away from us?

• Or is it when wavelengths of light stretch out because the object emitting light is racing toward us?