We humans have trouble comprehending something larger than, say, our planet (and even that isn't easy to conceptualize) and smaller than, say, a cell (once again, still not easy to think about). This tutorial explores the scales of the universe well beyond that of normal human comprehension, but does so in a way that makes them at least a little more understandable.
How does a bacteria compare to an atom? What about a galaxy to a star? Turn on your inertial dampeners. You're in store for quite a ride!