2D Universes Could Sustain Life, Scientist Finds
Some stories, though unrelated to our usual field, are just too interesting to ignore. This is one of them.
It is common knowledge – indeed, taken for granted – that all life exists in three-dimensional space and in one dimension of time. But is this mixture of 3 + 1 so vital to sustaining life? Could anything exist in five dimensions of space, or two of time?
Research by James Scargill of the University of California suggests that it just might be able to. His work states that a universe with two spatial dimensions and one temporal one could also work, overcoming critical problems with the issue of gravity and the necessity for a set degree of complexity.
In the past a number of scientists have spoken on the fixed nature of dimensions and the impossibility of changing the 3 + 1 formula. It was argued in the 1990s that having any more temporal dimensions than we already have would mean the laws of physics would lack the properties needed for observers to make predictions; while having more spatial dimensions would mean the laws of motion would become very sensitive to small disruptions, leading to no stable orbits forming and thus no solar systems.
Arguments have also been made against life surviving within universes with fewer dimensions than our own: because general relativity could not work in two dimensions, there would in theory be no gravity. Scargill refuted this in his paper, suggesting that a simpler scalar gravitational field would be possible in 2D, allowing for stable planar orbits.
Against the criticism that circumstances could never become complex enough to sustain life, Scargill points to neural networks. The complexity of these biological systems can be characterised by different properties that any 2D system must be able to produce.
Scargill questioned whether any 2D networks included certain complex neurological features in the brain, including the ability to traverse complex networks in a few steps (“small-world” properties), operating in a delicately-balanced regime between high and low activity, and modular hierarchy where small subnetworks combine to form larger networks.
Modelling 2D networks, Scargill determined that they could be built in a modular way and have all the properties he describes, potentially allowing for enough complexity to create some kind of life.
The next step is to complete Scargill’s graph with real neural networks, determining whether the networks really could support life.