The universe offers us, humans, with vast myriad possibilities and with its mysterious space bodies, we can visualise some of the most relatable objects as well. From NASA spotting a Halloween pumpkin structure to a beautiful ghost in the space, the chances are numerous.
Taking this casual game of spotting everyday objects in space, an astrophysicist and a neurosurgeon have come together and used quantitative analysis to compare two of the most complex systems in nature – the human brain and the galaxies in the Universe. The study stems from an image that occasionally gets shared around, showing a human neuron and a simulated galaxy cluster and how they look startlingly similar.
The recent study goes beyond the similarity of mere looks of the two and delves deeper into their scientific nuances. Astrophysicist Franco Vazza of the University of Bologna in Italy and neurosurgeon Alberto Feletti of the University of Verona in Italy have been investigating the same to determine the other similarities between the two.
In 2017, the two wrote for Nautilus Quarterly explaining how galaxies can group into massive structures (called clusters, superclusters, and filaments) that stretch for hundreds of millions of light-years. The Cosmic voids, the boundary between these structures and neighbouring stretches of empty space, can be extremely complex.
At these boundaries, gravity accelerates matter to speeds of thousands of kilometres per second, which creates shock waves and turbulence in intergalactic gases. The two scientists have predicted that the void-filament boundary is one of the most complex volumes of the universe in terms of measurement by the number of bits of information it takes to describe it.
This discovery got the two scientists thinking if the cosmic structure is more complex than the brain.
Even though the two structures differ in size by 27 orders of magnitude, the team’s results suggest that they can result in similar levels of complexity and self-organisation.
In terms of similarities, the human cerebellum has around 69 billion neurons while the observable cosmic web contains over 100 billion galaxies. Both of them are arranged in well-defined networks, with nodes, neurons in the brain, galaxies in the Universe, connected via filaments. Neurons and galaxies have a typical scale radius that is only a fraction of the length of the filaments. The flow of information and energy between nodes is only around 25 percent of the mass and energy content of each system.
In terms of composition, the brain is around 77 percent water and the universe is around 72 percent dark energy. A recent study by Vazza suggests that the memory of the human brain is around 2.5 petabytes. The study suggests that the memory capacity required to store the complexity of the universe is around 4.3 petabytes.