Physicists have long struggled to explain why the Universe began with conditions conducive to the evolution of life. Why do physical laws and constants take on very specific values that allow stars, planets, and ultimately life to develop?
The expanding force of the Universe, dark energy, for example, is much weaker than theory suggests – allowing matter to clump together rather than tear apart.
A common answer is that we live in an infinite multiverse of universes, so we shouldn’t be surprised that at least one universe has become ours. But another is that our universe is a computer simulation, with someone (perhaps an advanced alien species) fine-tuning the conditions.
This last option is supported by a branch of science called information physics, which suggests that spacetime and matter are not fundamental phenomena. Instead, physical reality is fundamentally made up of bits of information, from which our experience of spacetime emerges.
By comparison, temperature “emerges” from the collective movement of atoms. No atom basically has a temperature.
This leads to the extraordinary possibility that our entire universe is actually a computer simulation.
The idea is not so new. In 1989, legendary physicist John Archibald Wheeler suggested that the Universe is fundamentally mathematical and can be considered to emerge from information. He coined the famous aphorism “it from bit”.
In 2003, philosopher Nick Bostrom of Oxford University in the UK formulated his simulation hypothesis. This argues that it is in fact highly likely that we are living in a simulation.
This is because an advanced civilization would have to reach a point where its technology is so sophisticated that simulations would be indistinguishable from reality, and participants would not be aware that they were in a simulation.
Physicist Seth Lloyd of the Massachusetts Institute of Technology in the United States took the simulation hypothesis to the next level by suggesting that the entire Universe could be one giant quantum computer.
Some evidence suggests that our physical reality may be a simulated virtual reality rather than an objective world that exists independent of the observer.
Any virtual reality world will be based on information processing. This means that everything is finally digitized or pixelated down to a minimum size that can no longer be subdivided: bits.
It seems to mimic our reality according to the theory of quantum mechanics, which governs the world of atoms and particles. It indicates that there is a smallest discrete unit of energy, length and time.
Likewise, elementary particles, which make up all visible matter in the Universe, are the smallest units of matter. Simply put, our world is pixelated.
The laws of physics that govern everything in the Universe also resemble the lines of computer code that a simulation would follow in program execution. Moreover, mathematical equations, numbers and geometric patterns are present everywhere – the world seems to be entirely mathematical.
Another curiosity in physics supporting the simulation hypothesis is the maximum speed limit in our Universe, which is the speed of light. In a virtual reality, this limit would correspond to the processor speed limit, or processing power limit.
We know that an overloaded processor slows computer processing in a simulation. Similarly, Albert Einstein’s theory of general relativity shows that time slows down in the vicinity of a black hole.
Perhaps the most supportive evidence for the simulation hypothesis comes from quantum mechanics. This suggests that nature is not “real”: particles in determinate states, such as specific locations, do not appear to exist unless you actually observe or measure them. Instead, they are in a mixture of different states simultaneously. Likewise, virtual reality needs an observer or programmer to make things happen.
Quantum “entanglement” also allows two particles to be spookily connected so that if you manipulate one, you automatically and immediately manipulate the other, regardless of their distance – the effect being apparently faster than the speed of light, which should be impossible.
However, it could also be explained by the fact that in a virtual reality code, all “slots” (points) must be approximately equally distant from a central processor. So while we might think two particles are millions of light-years apart, they wouldn’t be if they were created in a simulation.
Assuming the Universe is indeed a simulation, then what kind of experiments could we deploy from the simulation to prove it?
It’s reasonable to assume that a simulated universe would contain lots of bits of information all around us. These bits of information represent the code itself. Therefore, detecting these bits of information will prove the simulation hypothesis.
The recently proposed principle of mass-energy-information (M/E/I) equivalence – suggesting that mass can be expressed in energy or information, or vice versa – states that bits of information must have a small mass. It gives us something to look for.
I postulated that information is actually a fifth form of matter in the Universe. I even calculated the expected information content per elementary particle. These studies led to the publication, in 2022, of an experimental protocol to test these predictions.
The experiment involves erasing the information contained inside elementary particles by letting them and their antiparticles (all particles have “anti” versions of themselves that are the same but have an opposite charge) annihilate in a flash of energy – emitting “photons”, or particles of light.
I predicted the exact range of expected frequencies of the resulting photons based on information physics. The experience is completely feasible with our existing tools, and we have launched a crowdfunding site to achieve this.
There are also other approaches. The late physicist John Barrow argued that a simulation would accumulate minor miscalculations that the programmer would have to correct for it to continue.
He suggested that we might experience such fixation when conflicting experimental results suddenly appear, like the constants of nature changing. Monitoring the values of these constants is therefore another option.
The nature of our reality is one of the greatest mysteries there is. The more seriously we take the simulation hypothesis, the more likely we are to prove or disprove it one day.
Melvin M. Vopson, Lecturer in Physics, University of Portsmouth.
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