Physicists have long struggled to explain why the universe began by providing conditions for the evolution of life.
Why do physical laws and constants take on the very specific values that allow stars, planets, and ultimately life to develop?
The expansive 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 turned out to be ours. Another hypothesis is that our universe is a computer simulation, whose conditions someone (perhaps an advanced alien species) is fine-tuning.
This last option is supported by a branch of science called information physics, which suggests that spacetime and matter are not fundamental phenomena.
Rather, physical reality is fundamentally made up of bits of information, from which our experience of spacetime emerges. In comparison, temperature “emerges” from the collective movement of atoms. No atom fundamentally has a temperature.
This leads to the extraordinary possibility that our entire universe may in fact be a computer simulation. This 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, the philosopher Nick Bostrom, from the University of Oxford in the United Kingdom, formulated his simulation hypothesis. According to this hypothesis, it is highly probable that we live in a simulation.
Indeed, an advanced civilization should reach a point where its technology is so sophisticated that simulations would be indistinguishable from reality, and participants would be unaware of being in a simulation.
Physicist Seth Lloyd of the Massachusetts Institute of Technology in the United States has taken the simulation hypothesis to the next level by suggesting that the entire universe could be one giant quantum computer.
And in 2016, business mogul Elon Musk concluded, “We’re most likely in a simulation” (see video above).
Empirical evidence
There is evidence to suggest 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 ultimately digitized or rasterized down to a minimum size that cannot be further subdivided: bits. It seems to mimic our reality according to the theory of quantum mechanics, which governs the world of atoms and particles.
It states 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. To put it simply, 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 of 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 near a black hole.
Perhaps the most compelling evidence for the simulation hypothesis comes from quantum mechanics. This suggests that nature is not “real”: particles in specific states, such as specific locations, do not appear to exist unless you actually observe or measure them.
On the contrary, they are simultaneously in a mixture of different states. Similarly, virtual reality requires an observer or programmer to make things happen.
Quantum ‘entanglement’ also allows two particles to be freakishly connected, so that if you manipulate one, you automatically and immediately manipulate the other, no matter how far apart they are – the effect being apparently faster than the speed of light, which should be impossible.
However, this could also be explained by the fact that, in a virtual reality code, all the “places” (points) should be approximately the same distance from a central processor.
So while we may think that two particles are millions of light-years apart, they wouldn’t be if they were created in a simulation.
Possible experiences
Assuming the universe is indeed a simulation, what sorts of experiments could we deploy inside the simulation to prove it?
It is reasonable to assume that a simulated universe would contain many bits of information all around us. These bits of information represent the code itself.
Therefore, detecting these bits of information will prove the hypothesis of the simulation. The recently proposed principle of mass-energy-information (M/E/I) equivalence – which suggests that mass can be expressed as either energy or information, or vice versa – states that bits of information must have a low mass. It gives us something to look for.
I postulated that information was 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 consists in erasing the information contained inside the elementary particles by letting them annihilate with their antiparticles (all particles have “anti” versions of themselves which are identical but have an opposite charge) in a burst of energy – by emitting ‘photons’, or particles of light.
I predicted the exact range of expected frequencies of the resulting photons based on information physics. The experiment is quite feasible with our current tools, and we have launched a crowdfunding site) to carry it out.
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 running.
He suggested that these corrections could result in the sudden appearance of contradictory experimental results, such as changing constants of nature. 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.
Translation of The Conversation by Astro Univers
