Cajal's Cramps

The idea is not new: what if small worlds existed within much larger worlds? In other words, what if the Earth is to our universe as a cell is to the human body; or a civilization created its world in a speck of dust and lived oblivious to the existence of the much larger world to which that speck belonged (like the inhabitants of Whoville in the children’s book and animated film Horton Hears a Who!)? The concept can help us understand how the different cells of our body work and interact with each other.