Some people think it is likely that our universe is part of a simulation. Whether or not this is true is perhaps a question for philosophers, but certain recent scientific discoveries could potentially give support to this idea.
What would it mean for us to live in a simulation? The whole of the universe would be part of a computer programme run by an advanced civilisation. We already run simulations of simple systems such as traffic flow: it seems at least possible that an advanced enough civilisation with a sufficiently powerful supercomputer could run a simulation of an entire universe, to study the origins of life, for example. Perhaps it could even be so sophisticated that the simulated life would have conscious experiences as we do. Although this seems far-fetched, there is no reason to doubt that this could, one day, be possible.
Of course, such a simulation would consume vast amounts of computing power and resources. As a result, the operator might consider taking shortcuts and many of these eerily mirror the weirdest scientific discoveries of the last century.
In the quantum world of the very small, we find many strange things occurring, for example, the seeming indecisiveness of the universe. You may have heard of Schrödinger’s cat, which is simultaneously dead and alive in a box until we open it to look. It is an analogy for how quantum objects exist in strange, fuzzy states until we check up on them. For example, a radioactive nucleus can have both decayed and not decayed until it is observed.
If a computer was trying to save processing power in its grand universe simulation, we can imagine it employing a similar strategy: by only deciding, so to speak, the exact state of a quantum (and, therefore, normally insignificant) object, it could avoid processing the trillions of quantum level events which happen every fraction of a second. It would only have to decide the state of a system when its result mattered, such as when we check or when the state of the radioactive nucleus affects its interactions. We see exactly this with an effect called decoherence. This happens when a quantum system interacts with things around it, causing the fuzzy state of the nucleus having both decayed and not decayed to make up its mind and take on a definite state. This would thus save a huge amount of processing power so it would be a step that the operator would likely take.
In the early 20th century, Albert Einstein published his scientific papers on his theories of Special and General Relativity. One of the amazing things which he proved was that time flowed at different rates for observers moving at different speeds or in the presence of large gravitational fields. An effect of this is that objects moving close to the speed of light experience time passing more slowly. In open world video games (essentially basic simulations), moving very fast causes the game to lag (time to slow down) as the game struggles to render all the new environments it is entering. Similarly, when a game tries to keep track of many objects on the screen at the same time, it also lags. This perfectly imitates how time passes more slowly in the presence of large gravitational fields as if a supercomputer was trying to render a lot of mass at once.
Of course, this does not prove that we live in a simulation, but it does lend weight to the idea. It is certainly interesting how well unintuitive areas of physics match up to the idea of a computer economising on disc space and processing power.
Original image by Rosie Case