Interestingly enough, the total number of neurons in the human brain falls in the same ballpark of the number of galaxies in the observable universe.
It is truly a remarkable fact that the cosmic web is more similar to the human brain than it is to the interior of a galaxy; or that the neuronal network is more similar to the cosmic web than it is to the interior of a neuronal body. Despite extraordinary differences in substrate, physical mechanisms, and size, the human neuronal network and the cosmic web of galaxies, when considered with the tools of information theory, are strikingly similar.
http://nautil.us/issue/50/emergence/the-strange-similarity-of-neuron-and-galaxy-networks