One of These Pictures Is the Brain, the Other is the Universe. Can You Tell Which is Which?
“Science is not only compatible with spirituality; it is a profound source of spirituality. When we recognize our place in an immensity of light years and in the passage of ages, when we grasp the intricacy, beauty and subtlety of life, then that soaring feeling, that sense of elation and humility combined, is surely spiritual.” – Carl Sagan “The Demon-Haunted World.”
Learning about the Universe, I’ve felt these spiritual moments as I better understand my connection to the wider everything. Like when I first learned that I was literally made of the ashes of the stars – the atoms in my body spread into the eternal ether by supernovae. Another spiritual moment was seeing this image for the first time:
A neuron in the brain juxtaposed with clusters of galaxies and their connected filaments of matter and dark matter. The resemblance is immediately clear. The implication? You may have an entire universe in your head. But the similarity between the images could simply be a case of apophenia – perceiving likeness where none actually exists. After all, how can these two things be similar given the vast difference in scale between them? But what if beyond the visual similarity between the networks of neurons in the brain and webs of galaxies in the Cosmos, an objective measurement could compare just how similar they truly are? That’s what Franco Vazza (astrophysicist at the University of Bologna) and Alberto Feletti (neurosurgeon at the University of Verona) set out to discover combining both their disciplines for a publication in “Frontiers of Physics.”
An Intergalactic Link
The human brain is literally one of the most complex structures known in the Universe – which is itself the greatest of all complexity. Your brain has about 80 billion neurons – the cells that process input from the senses and send signals to your body through the nervous system. Neurons are also networked, communicating to each other through connections called axions and dendrites. There are on the order of 100 trillion connections between neurons forming the neural network that creates who you are.
The Universe is networked as well. While we may think of space as objects separated by vast tracts of…well…space, that’s not entirely the case. The Universe we see with our scientific equipment is referred to as the “Observable Universe” approximately 90 BILLION light years in diameter and containing on the order of hundreds of billions to a few trillion galaxies. These galaxies, like our Milky Way, collections of billions of stars, are themselves grouped into galaxy clusters. Our Milky Way is part of the “Local Group” which contains the neighbouring Andromeda and Triangulum galaxies as well as 50 other galaxies. Those galaxies are in turn part of a larger group called the Virgo Supercluster. The space between groups and clusters is not empty but rather hosts connecting filaments of both ordinary and dark matter that stretch for millions of light years. In this way, the Universe can be thought of as a giant network of galaxy clusters all interconnected similarly to neural networks in the brain. That network is called the Cosmic Web.
A simulation of the formation of the Cosmic Web from the beginning of time to the present
A Universe Within a Universe
The research to find quantifiable similarities between both networks was born in a partnership between neuroscience and astrophysics. Using techniques and tools from both disciplines, Vazz and Feletti looked at these two networks to find quantifiable similarities beyond the perceived visual similarity. Were these networks comparable and, if so, what does that mean?
The researchers used 4 micrometer thick slices of the human cortex – the outer layer of the brain which is responsible for processing language, sensory information, thought, memory, and consciousness. These were compared to 25 megaparsec (1 parsec = approx. 3.26 light years) thick “slices” of Universe taken from a computer simulated volume of 1 million cubic megaparsecs of space. The slices of brain and Universe are relatively comparable in thickness then given that both are 27 orders of magnitude in size different from each other.