Ask HN: Assume the universe is a simulation. Why is c the speed of light? • Hacker News Board

Re: Ask HN: Assume the universe is a simulation. Why is c the speed of light?

#11

Post by kleer001 » Wed, Dec 02, 2015, 11:52 PM UTC

PythonDeveloper wrote: post #4

In order for any simulation to proceed at a steady state, there must be at least one constant. Everything else can be variable, but in order for time to progress at the same "tick", it has to have something to measure by. That said, why create a "tick" when the perception of that tick can vary by individual? When I go into code mode, 10 hours can slip by in an instant, and I'm not hungry or thirsty until I come out o…

This "tick" theory gets my vote.

I see c as an emergent quality of a base granularity. If the universe is a cellular automata then c would be related to the distance between two successive layers, between what just happened and what is happening now, between now and next.

Re: Ask HN: Assume the universe is a simulation. Why is c the speed of light?

#12

Post by thomas-b » Thu, Dec 03, 2015, 12:01 AM UTC

Could just be a bug between time and space being linked while it should not.

Or we need to buy the FTL DLC

Re: Ask HN: Assume the universe is a simulation. Why is c the speed of light?

#13

Post by sjg007 » Thu, Dec 03, 2015, 12:59 AM UTC

pjungwir wrote: post #10

staunch wrote: post #6

What video game doesn't have constants? const LIGHTSPEED = 299_792_458

How many significant figures does it need to have, do you think? And that makes me wonder, how does this simulation deal with irrational numbers and real numbers? How does it represent pi and radical 2? The Greeks were afraid of these numbers. Are they are problem for a theory that we are a simulation run on finite resources?

I think it has to do with the concept of computable vs non computable functions. One stand is that if the Universe is a simulation then by definition it is computable but we can clearly define and reason about non computable things (which suggests that it is not in fact just a Turing machine and may in fact the hyper computer running the simulator. But you can't really get above that. So the speed of light is just a defined constant which no meaning and we can't pierce the through hypervisor.

https://en.wikipedia.org/wiki/Simulated_reality#Computationa...

Re: Ask HN: Assume the universe is a simulation. Why is c the speed of light?

#14

Post by brudgers » Thu, Dec 03, 2015, 1:34 AM UTC

The puzzlement consists of using "universe" in two incompatible contexts without paying clear attention to the distinction between the contexts.

The first context is the ordinary one in which the universe is roughly the container for everything that is including ourselves.

The other context is one in which the universe is a simulation of a container for everything that is including ourselves that is indistinguishable by us from an actual container for everything that is including ourselves.

It's fine to use the latter definition, so long as one recognizes that the use is very odd and problematic and any conclusions one draws while using it are simulated conclusions about the simulated container and not conclusions about the actual container for everything that is including ourselves. To put it another way, if the universe is a simulation then "light" and "speed" and "C" refer to elements of the simulation and need not have a one to one correspondence to entities in the actual universe. Human knowledge can only be knowledge of the simulation.

Our knowledge is limited to things it is possible for humans to know. If we're in a simulated universe, then we can only know about the simulation.

Re: Ask HN: Assume the universe is a simulation. Why is c the speed of light?

#15

Post by fallingfrog » Thu, Dec 03, 2015, 3:15 AM UTC

If the universe is a simulation, it would have to be on an analog computer which doesn't have a clock speed as such. Or a digital computer running sufficiently tiny time steps to be indistinguishable from an analog computer. In either case I don't think c is directly related to "clock speed". I'm not a good enough physicist to tell you what it does mean. That's my feeling anyway.

Re: Ask HN: Assume the universe is a simulation. Why is c the speed of light?

#16

Post by irascible » Thu, Dec 03, 2015, 10:58 AM UTC

It's the refresh rate of "their" displays.

Re: Ask HN: Assume the universe is a simulation. Why is c the speed of light?

#17

Post by theSage » Thu, Dec 03, 2015, 11:24 AM UTC

fallingfrog wrote: post #15

If the universe is a simulation, it would have to be on an analog computer which doesn't have a clock speed as such. Or a digital computer running sufficiently tiny time steps to be indistinguishable from an analog computer. In either case I don't think c is directly related to "clock speed". I'm not a good enough physicist to tell you what it does mean. That's my feeling anyway.

I would be inclined towards digital due to the presence of Planck length and Planck time.

Re: Ask HN: Assume the universe is a simulation. Why is c the speed of light?

#18

Post by thiago_fm » Thu, Dec 03, 2015, 11:58 AM UTC

c is the speed of light because then you can create a constraint over the size of the universe, also make everything that is placed inside of this universe that has mass locked inside it, as it would take infinite energy to get something with mass(which also would go to infinite) to be at the same speed of light.

Re: Ask HN: Assume the universe is a simulation. Why is c the speed of light?

#19

Post by csorrell » Thu, Dec 03, 2015, 3:22 PM UTC

It is my understanding that when determining the official figure,the General Conference on Weights and Measurements took an average of some of the most accurate measurements that were available at the time. But I think that there were variations in each case. So we could assume that either our tools were just not precise enough, or that the speed of light is not actually constant. (or both?) I'm curious, are physicists these days routinely measuring the speed of light, and if so are these measurements consistent?

Re: Ask HN: Assume the universe is a simulation. Why is c the speed of light?

#20

Post by hacknat » Thu, Dec 03, 2015, 9:21 PM UTC

It is the fixed rate at which all mass-energy is moving through space-time. The rate never changes for anything. If an object is moving slowly through the space axis of space-time then it is moving quite rapidly, though at a fixed and predictable rate, through the time axis, and vice versa. C is the rate at which time and space are flowing in the simulation. Clock speed is a good analogy.