If recent measurements of cosmic ray particles are correct, then we may have the first evidence that the universe as we know it is really a giant computer simulation.

Humans have explored the laws of our universe for many years now, and it's not uncommon to hear people talk about how amazing it is that certain fundamental values are just right for life to exist. Some people have wondered if that's because the whole universe is actually some kind of sandbox simulation, and we're merely characters in some cosmic game of The Sims. If that's true, then there should be a point where we start to bump up against the edges of the simulator, like Jim Carrey's character escaping from The Truman Show -- and now a team of physicists think that a particular measurement of some cosmic ray particles might be the first such indication of one of those edges.


The idea that we might be living in an artificial reality constructed by something higher than ourselves has been a recurring philosophical hypothesis for centuries. Plato's Allegory of the Cave, Descartes' evil demon, Putnam's brain in a vat -- these are all variants of justifications for solipsism, a philosophical idea that says it's impossible to know with any certainty whether the world as we experience it is "real" or a simulation projected by some external entity. Keanu Reeves' character Neo in The Matrix opts for a dose of reality when he chooses to take the red pill, but figuring out whether our universe is "real" or not is a touch more complicated than that.

It shouldn't be surprising that simulating the universe would take up a lot of processing power, since the universe is exceedingly large (and then some). Currently, if we wanted to simulate quantum chromodynamics -- the rules which give rise to the strong nuclear force, which binds protons and neutrons together in atomic nuclei -- we can only manage it on the scale of femtometres (millionths of a nanometre). That's not even close to the level of detail needed for even the smallest microorganisms, let alone planets, stars and galaxies.

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What we do know, though, is that when we create such a simulator, there's some kind of underlying lattice that holds everything together like a kind of framework. Think of it as the smallest scale at which a simulator runs -- like the way a grid divides up the playable space in a chess game. You can't move a piece less than one grid space.

If we were living in a simulator, we'd expect to find evidence of that lattice if we looked close enough to the edges of the observable universe -- and that's what Silas Beane from the University of Bonn and colleagues have calculated, in a paper published in arXiv. As cosmic particles fly through the universe, they lose energy and change direction and spread out across a spectrum of energy values.

There's a known limit to how much energy those particles have, though, and Beane and his colleagues have calculated that this seemingly arbitrary cliff in the spectrum is consistent with the kind of boundary that you'd find if there was an underlying lattice governing the limits of a simulator. It should also, if present, scatter the particles in a certain way as they come up against it, and we should be able to investigate whether that's the case.


If such an investigation does look consistent with a simulator lattice, then that could mean several things. It could show us that there's a boundary out there consistent with Beane et al's hypothesis, and it works a bit like the one we'd expect if we were living inside a simulator based on the same principles as one we would also build. It could be, though, that we're incorrectly interpreting evidence of certain fundamental laws we are as yet unfamiliar with. It could even be that this isn't evidence at all for a simulator, as a real lattice might work in a different way to how we would envision it.

Frankly, we don't know yet. It's a bit like sitting really close to the TV when you're a kid and being able to pick out all the pixels -- we just have to hope the universe doesn't have a retina display.

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