Physics

Do gravitational anomalies prove we're not living in a computer simulation?

Researchers from Oxford and the Hebrew University believe they've found proof that the universe is too complex to exist inside a computer simulation
Researchers from Oxford and the Hebrew University believe they've found proof that the universe is too complex to exist inside a computer simulation
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Researchers from Oxford and the Hebrew University believe they've found proof that the universe is too complex to exist inside a computer simulation
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Researchers from Oxford and the Hebrew University believe they've found proof that the universe is too complex to exist inside a computer simulation
Artistic impression of a space-time twist in a crystal
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Artistic impression of a space-time twist in a crystal
Researchers from Oxford and the Hebrew University believe they've found proof that the universe is too complex to exist inside a computer simulation
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Researchers from Oxford and the Hebrew University believe they've found proof that the universe is too complex to exist inside a computer simulation
Artistic impression of a space-time twist in a crystal
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Artistic impression of a space-time twist in a crystal

Is our entire universe just a computer simulation? It sounds like the premise for a sci-fi movie, but over the years the idea has been debated by scientists in earnest. But now theoretical physicists believe they've found proof that our universe is far too complex to be captured in any simulation. According to the researchers, the hypothesis is done in by gravitational anomalies, tiny "twists" in the fabric of spacetime.

For many, the concept that our civilization might exist inside a simulation goes back to the movie The Matrix, but it has actually been discussed in scientific circles as a legitimate possibility, including at the Isaac Asimov Memorial Debate at the American Museum of Natural History last year. Oxford philosopher Nick Bostrom proposed the idea in a 2003 paper, and the general crux of his argument is a bit of a numbers game.

The simulation argument

Essentially, Bostrom suggested that at the rate technology is advancing today, it's likely that future generations will have access to supercomputers beyond our imagining. And since we tend to use computers to run (relatively primitive) simulations with our current technology, those future humans (or another advanced species) would likely do the same, perhaps simulating their ancestors. And with all that extra processing power at their disposal, it follows that they would run many simulations simultaneously.

As a result, the amount of artificial universes would vastly outnumber the one "real" universe, so statistically it's far more likely that we live in one of these simulations. Astrophysicist Neil deGrasse Tyson puts our odds of living in a simulation at 50/50, while Elon Musk is far less optimistic, saying the chance is "one in billions" that we inhabit the one true world.

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Taking the idea to the extreme, some even blame the election of Trump and the unprecedented Best Picture mixup at this year's Oscars on malicious higher beings deliberately messing with our virtual world, like bored Sim City players.

Gravitational anomalies

While it sounds like a fun thought experiment that's impossible to verify, researchers at Oxford and Hebrew University may now have proven that the universe is far too complex to simulate. The key is a quantum phenomenon known as the thermal Hall conductance – in other words, a gravitational anomaly.

These anomalies have been known to exist for decades, but are notoriously difficult to directly detect. Effectively representing twists in spacetime, they arise in physical systems where magnetic fields generate energy currents that cut across temperature gradients, particularly in cases where high magnetic fields and very low temperatures are involved.

Artistic impression of a space-time twist in a crystal
Artistic impression of a space-time twist in a crystal

Quantum simulations

Monte-Carlo simulations are used in a wide variety of fields, from finance to manufacturing to research, to assess the risks and likely outcomes of a given situation. They can process a huge range of factors at once and simulate the most extreme best- and worst-case scenarios, as well as all possibilities in between.

Quantum Monte-Carlo simulations are used to model quantum systems, but the Oxford and Hebrew scientists found that quantum systems containing gravitational anomalies are far too complex to ever be simulated. The quantities involved in the simulation will acquire a negative sign – essentially, there's an infinite number of possibilities, so the simulation can't possibly consider them all.

Pushing it further, the team says that as a simulated system gets more complex, the computational resources – processors, memory, etc – required to run it need to advance at the same rate. That rate might be linear, meaning that every time the number of particles simulated is doubled, the required resources also double. Or it could be exponential, meaning that those resources have to double every time a single new particle is added to the system.

That means that simulating just a few hundred electrons would require a computer with a memory made up of more atoms than the universe contains. Considering our universe contains 1080 particles – that's a 10 followed by 80 zeroes – the number of atoms needed to simulate that is incomprehensible and utterly unsolvable.

"Our work provides an intriguing link between two seemingly unrelated topics: gravitational anomalies and computational complexity," says Zohar Ringel, co-author of the paper. "It also shows that the thermal Hall conductance is a genuine quantum effect: one for which no local classical analogue exists."

The research was published in the journal Science Advances.

Source: Oxford University via Eurekalert

14 comments
Nik
If you simulate a universe, then simulating all the particles of it is part of that. Given the unknown technology to do that, then saying that its too complicated to, simulate the quantities required, is a nonsense.
piperTom
Yes, those anomalies do prove you are not in a simulation... which is exactly why I sprinkled a few of them in there for you. Ha, ha, ha!
toyhouse
The very concept itself answers the question. If it's a simulation, then all we know is what it presents and everything in it is a part of it. The possibilities are infinite. How would we even know if multiple simulations were running? Each one of us could be the only one here. Or in our own simulation different from everyone else - programmed to except the rules or not. Or the rules could constantly be changing as we go in a way that goes un-noticed or is excepted as normal. How would you know? Hahaha. I hope the overlords are amused. Depressing maybe, but a fascinating topic just the same.
aki009
I don't see why it would be necessary to simulate all the particles and interactions of the universe to present a reasonably coherent view to anyone caring to look. I'd expect that one only needs to maintain reasonable state information, and present an absolute answer only when an observation is made. And why would it not be possible to modify past observations for consistency as needed, given that it is a simulation? Perhaps the very existence of phenomena such as the Heisenberg uncertainty principle have their roots in an architectural choice the simulation designers made. ... or not.
BrianK56
We seem to be thinking in our most current technology form which could be totally obsolete in another world. 0s and 1s may be all that we can fathom, what if there is computing in another form that we have never thought of.
fb36
My interpretation of this news is, from what I read from multiple sources, this result applies only for classical computers; not for quantum computers. And this limitation of classical computers being unable to be simulate our (quantum) reality was already known for decades.
Douglas Bennett Rogers
The Mind of God theory is kind of an old idea, only now we have a means to rationalize it. God has as much computational capacity as is necessary. Besides that, all that is needed is enough capacity to exercise an individual mind. This may be achieved within a few decades.
j wunder
We could still be living in a simulation. You don't need to simulate every low level event in the universe, just enough higher level events to to make it appear to your consciousness that the world adheres to some lower level model, like quantum mechanics. The universe would expand consistently from the top down wherever you direct you attention, rather than emerge from the bottom up. It would be much more efficient too, with the inherent ability to simulate almost any kind of universe imaginable. If true, the universe would be much smaller than it appears to be. Stars would be little more than points of light. Not sure, but consciousness may also require special status in this model, which would be consistent with the fact that we currently can't explain it.
Kristianna Thomas
Are we living in a computer driven simulation? I say the answer is yes. We are living in a computer driven simulation. Unfortunately, this is much older than the Matrix, and the history that we have experienced is a total fabrication. We are living outside the main corridor of reality and our past, present and future is all a lie. The story of the Matrix is nothing new and is a repeat of the reality that we are not part of. Is reality real? Yes. Are we living our lives in the real world? No. Can we deal with the truth? No. Will we reject this truth? Yes. Will we keep believing in the lie? Yes. Am I putting my sanity up for question? Yes. But who really gives a flying fuck? Will people laugh and make rude jokes about what I say? Yes. But do I give a hoot? No. This is truth. What we do with it does not add up to a hill of pork and beans. Maybe there are those who really give a hoot, and will try to change things for the better. Maybe there is no way of turning things around, because there is no way of knowing what is the truth and what is a lie. When you walk down a long hallway, you can't turn around and realize that what you did; actually did not happen. The universe is not a simulation; the reality we are in is a simulation. Remember. the Matrix is just a higher form of VR, it just gets plugged into your brain stem.
richard41
Not an expert on either physics, computer science or math, but doesn't this conclusion overlook the fact someone in the future might come up with a computer algorithm that solves the number crunching problem?