Computing a Universe Simulation

Physics seems to be telling us that it’s possible to simulate the entire universe on a computer smaller than the universe.

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Jin Du
Loren Booker
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Ian Grams

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Previous Episode:
How to Detect Extra Dimensions

Hosted by Matt O'Dowd
Written by Matt O'Dowd
Graphics by Luke Maroldi
Assistant Editing and Sound Design by Mike Petrow

I’m not saying the universe is a simulation. I mean it might be – I’m just not saying it. And perhaps it doesn’t make any difference. Even if this is the prime, the original physical universe, rather than somewhere deep in a simulation nest, we can STILL think of our universe’s underlying mechanics as computation. Imagine a universe in which the most elementary components are stripped of all properties besides some binary notion of existence or non-existence. Like, if the tiniest chunks of spacetime, or chunks of quantum fields, or elements in the abstract space of quantum-mechanical states can either be full or empty. These elements interact with their neighbors by a simple set of rules, leading to oscillations, elementary particles, atoms, and ultimately to all of the emergent laws of physics, physical structure, and ultimately the universe.

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سلطان الخليفي

[CevelNet]

You know you did an extremely good job at AI programming, when the characters in your simulation start wondering if they are simulated.

[DeGebraaideHaan]

Your universe needs to restart to install important updates...

[clairecelestin]

I appreciate that those with sufficient information storage and processing to answer the challenge question are awarded a prize proportional to their surface area

[terryboyer]

I've always imagined our "universe" was just a junior high school kids entry for a science fair in the real universe.

[NaumRusomarov]

This is probably one of the more fundamental episodes as it shows that the universe might be informational in nature.

[Jordan-zkwd]

Actually Switzerland is rotating, so a nonrotating neutral black hole isn't perfectly analogous to Switzerland.

[alexjjgreen]

maybe turn off those ram hungry extra dimension visuals in settings

[ToastedFanArt]

Dang that Switzerland dig was savage...

Edit: For those that missed the joke, he said Switzerland was also "a non-rotating, neutral black hole".

[matta]

If it's a simulation, thank God it allowed me to experience the 80's.

[hoffmankspengineering]

I have a bit of a theory regarding a computational universe: essentially, gravity wells form around areas where there is a lot of mass and energy. The more particles are packed into a space, the more interactions happen between particles and thus the more information that is being processed. Now, (here is the part where I make an assumption) IF the universe has a decentralized computational bottleneck ( in other words, the more computation happening in a localized area, the slower it goes ), it would create a time dilation effect around gravity wells similar to what happens in relativity. Black Holes would then be areas where the computations are queueing up faster than they can be processed.

[jardy]

Hey Matt. I think the fact that we cannot simulate the universe within our universe is dependent on one assumption.
The assumption is that we need to simulate every atom. Which might not be correct per se.
If we look at the Delayed Choice experiment, we can see that photon's paths are not calculated as if they are particles unless they are observed.
I'm a Software Engineer, and if i had to write a program that would simulate the universe - that's the same thing I would do. I would abstract things into simpler items. So light becomes a basic wave that consumes an order of magnitude less computing power than if I calculated each photon. Same goes for all kinds of particles. Why do I need to calculate what each atom in a core of a planet is doing, if i can just simulate a planet good enough to not be distinguishable from a 100% simulation?
Only when the particles are being directly observed, would I use 100% simulation, to hide the fact that it's a simulation.
In my opinion, this will allow us to simulate the universe to be indistinguishable for the average observer, in real-time.

Cheers.

[jacoblongwell]

we are going to need a better compression algorithm.

[mattio]

In a 1D world, are there Point-Earthers?

[JohnGrahamsBlog]

Was the camera on Matt out of focus in this episode?

[moofymoo]

3:20 - is it possible to make a doomsday device that downloads cat videos from youtube and stores it all in tiny region of space to make a black hole?

[zero]

If you can simulate the universe on a computer smaller than the universe, then can you simulate that simulation on something even smaller? It seems like the implication should be that the universe has limitless computational capacity if that's the case, but I don't get how that could make sense

[mememem]

What if the universe is pre-rendered? And/or compressed with lossy algorithms?

[wazzzuuupkiwi]

I really respect pbs's dedication to proper pronunciation. the amount of times I've heard "Swarts Child" over 'Swardz shild' made this episode refreshing

[CinemaRockPizza]

You are off focus, dude - in that case you seem to be not fully rendered...

[IanGrams]

Oh snap I got picked. Hi Mom! I will cherish the t-shirt immensely.