Relativity
From Simulism
Contents |
[edit] Introduction
Relativity is a scientific theory originally invented by Albert Einstein to account for the invariancy of the speed of light, meaning the speed of light (in vacuum) is a fundamental constant for all observers who measure it, independant of their own speed. The invariancy of the speed of light was first theorized by James Clerk Maxwell, when he stated his laws of the electric and magnetic field in 1865:
and 
This invariancy was experimentally verified by Michelson and Morley in 1887. Various explanations for this fact have been tried, including the so called luminiferous aether theory, which was rejected by the Michealson-Morley expiriment. Einstein's work is based on an idea, stated independantly by Dutch physicist Hendrik Antoon Lorentz and George Francis FitzGerald, that moving objects are subject to contraction in the direction of their respective speeds, the so called Lorenz-Fitzgerald contraction.
The fundamental idea of relativity is the fact that simultaneity does not exist, as people have believed for thousands of years, or, more simply put: time is relative. Two distinct events that seem to happen at the same moment according to Alice, happen separated in time according to Bob.
Without going too much in detail, time (and, as a consequence, spatial relativity) relativity is depending on relative velocity (as predicted by special relativity) , and the presence of matter in the universe (as predicted by general relativity).
Over the course of years, experiments have been conducted that support Einstein's theory.
[edit] Relativity and the simulation
[edit] A basic simulation
Lots of simulations involve the use of a grid mapped to all points in space, not unlike Conway's game of life. For our universe, this grid could be an array with three subscripts, able to address any point in our universe. The strategy is to calculate the interaction of all points, and from this interaction, calculate the next state of the grid, as is generally done in CFD calculations. The previous state may then be discarded or stored to disk. The grid array might even have four subscripts, the fourth being the time parameter. In this case all previous states reside in the computer's memory.
[edit] Integrating relativity
Integration of general and special relativity demands integrating the absence of absolute simultaneity. This means that the "basic" concept of the gridded simulation must be elaborated to a very high degree, or even abandoned in favor of another simulation algorithm. The programmer is challenged with the fact that events calculated on a point in time t cannot be simultaneously presented to an observer who happens to watch these events that same moment in time. Events calculated to appear at the same moment happen on different times according to this observer.
[edit] Computational consequences
If simulation wasn't demanding enough, the required level of elaboration might very well impose increased demand on the simulating hardware capacity in order to present every conscious observer with the correct version of reality.
[edit] So why bother
Some articles about simulism mention that the detail level of the simulation could be decreased when some conscious being is not looking. The core of the earth cannot be reached with current technology, so only its macroscopic properties need to be evaluated. The same holds for stars and constellations so far away we can not reach them (if they are not populated with conscious life).
Implementation of relativity could serve as a means invented by our creators that we will never succeed into moving FTL (faster than light) despite some current dreams about warp engines and worm holes. So we will be very unlikely to ever go these remote stars, only to discover there's nothing there, or at least not what we expected to be there.
Sure there could be cheaper ways of preventing us from moving over there, so the use of the relativity algorithm for just this purpose could be questionable.
[edit] Relativity as Evidence for a Simulation
The basic statement of relativity is: Time goes slower if the object has very much mass or is very fast (close to the speed of light).
Assume the simulation is not at a human-brain level but at a sub-atomic level. It seems logical that the more particles (or quarks or whatever) you need to simulate, the more computer power you need. Furthermore, as the speed of a particle increases, more computer power is needed for collision checking (i.e. if the particle collides with other particles), influences of gravity, etc.
Now assume the simulation uses discrete timesteps (but this also works for continuous time). In each timestep, every particle can only use a given amount of computer power. Thus, if a particle is surrounded by many other particles, "time" will go slower, because much more calculations are needed. The same goes for very fast particles.
Note that this assumes that "mass" and "number of particles" are related, i.e. that there is some "smallest particles" with fixed mass. Even if that is not the case, this argument might still hold, as we do not know anything about the scaling of the algorithms in the simulation.
Here is a link for a fast collision detection algorithms. http://graphics.ewha.ac.kr/FAST/ Note that it is hard to give a runtime in O-Notation. Could someone with a better understanding of physics write about how this relates to our understanding of what we call reality?
[edit] The programmer's world
If relativity was indeed invented to limit our abilities of moving FTL, our creators world might not be subject to relativity, meaning this world will be very different from ours.
A consequence of relativity is the possibility to convert matter into energy, and vice versa. Not only does it render time to be relative, it is also the mechanism that makes the sun burn, and allows for the existence of nuclear power plants and (thermo)nuclear weapons (which might be used to annihilate ourselves).
Obviously, the world of our creators than cannot have these feats, and must use different sources of energy.
[edit] Conclusion
Implementing the theory of relativity might impose an increased (or improbable) load demand on the simulating hardware, which diminishes the likelihood of any reality being really simulated.
If the world we live in is the real world, then it follows that relativity is a fundamental part of the real world.
Or if we live in a simulation, it might be that relativity was introduced as a "speed hack" as the creators were not interested in what happens in supermassive black holes. If relativity was indeed invented by our creators, and not a fundamental part of their world, their world is probably unimaginably different from ours.
