Try this exercise to visualize the universe as astronomers see it.
Take a deflated balloon and draw small stars on it with a marker.
The stars represent galaxies. Label one the Milky Way, for our galaxy.
Now, blow up the balloon. The growing balloon is similar to the expanding universe.
You will see how the stars spread out, which is something like the way galaxies move apart.
The air inside the balloon represents the past; the balloon surface represents the present; and the air surrounding the balloon represents the future.
Blowing up a balloon dotted with “galaxies” can give you an idea of how the universe is expanding.
