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It's possible that a bigger universe exists that can simulate ours. However I think whether a simulation of only the perceivable universe is not possible, whic

It's possible that a bigger universe exists that can simulate ours. However I think whether a simulation of only the perceivable universe is not possible, which means you can't reduce the required computation. See my reply to a sibling comment. If the universe is incompressible then it's definitely impossible to simulate it within itself.

scoutt 6y ago
Sorry. I read incomprehensible instead of incompressible. Perhaps the far universe we perceive and will perceive is not there anymore. It doesn't have to. What we perceive is its light (or electromagnetic/gravitational waves). Objects far away could have been garbage-collected millions of years ago. You don't need to compute them anymore. If the simulation has a limited time to run, then you can create and delete objects while playing with the speed of light to carry whatever information to us. Edit: millions of years ago is not needed. They could have garbage-collected the objects as soon as they complete the time for duration of the simulation. Whatever it is, I would save this information as a template for future simulations.
- seventhtiger 6y ago
  That definitely would work for Earth today. But note that to simulate observers on Earth today, you had to simulate from the big bang up to (today - light-crossing time from body) for each celestial body. That's significantly larger than Earth, only to simulate Earth today, because tomorrow the entire universe would go dark. Lightspeed gives structure to the computation of the universe but it doesn't reduce the load. Saving templates doesn't reduce the load either, not in the sense I'm considering. It may practically mean that you don't have to run it again, but theoretically if you want to know how much computation got you to this point then you have to count the computation of the templates. So if you had our whole universe at your disposal, and knowledge of all natural laws and processes, and knowledge of the starting conditions, and absolute power over matter and energy, you still cannot simulate our entire universe with anything less than just restarting it. If you wanted to simulated it specifically for some observers, you can free up resources using the lightspeed method but that's a computational debt you cannot pay if you wanted the simulation to continue.
  - scoutt 6y ago
    Yes, the simulation has to have a limited duration. > Lightspeed gives structure to the computation of the universe but it doesn't reduce the load. The load would be saved because you don't need to keep computing interactions between object, because we don't get to see these object/interaction since the simulation has a limited time. You save this pre-render of the universe and you just need to calculate whatever is closer to us (and our simulated world). You don't need to calculate all at once and you don't need to calculate since the big bang, since we will experience a very short period in the simulation. And I suppose most of it can be just faked. Imagine a spherical universe with the Earth at the center. You can calculate the outer portion of the sphere, then garbage-collect, then the result is added to the calculation for an inner portion, then garbage-collect, an so on until you reach the center of the sphere. Another thing is the time-constant. Why our time has to pass with the same speed as the time outside the simulation^? What we think it takes time to calculate it's now completely relative. If time is infinite in the real universe, then they have plenty of time to build our world so effectively that our entire existence is ran in a fraction of a second. Other aspect is why our universe has to be of the same quality of the real universe. Perhaps we have a sloppy version that is easier to calculate (but it's still complex for us to understand). Of course, I'm just drinking my coffee and playing I am a genius this evening: I'm not going to defend the above as in a real analysis. Edit: ^changed calculation for simulation.

scoutt 6y ago

Sorry. I read incomprehensible instead of incompressible. Perhaps the far universe we perceive and will perceive is not there anymore. It doesn't have to. What we perceive is its light (or electromagnetic/gravitational waves). Objects far away could have been garbage-collected millions of years ago. You don't need to compute them anymore. If the simulation has a limited time to run, then you can create and delete objects while playing with the speed of light to carry whatever information to us. Edit: millions of years ago is not needed. They could have garbage-collected the objects as soon as they complete the time for duration of the simulation. Whatever it is, I would save this information as a template for future simulations.

seventhtiger 6y ago
That definitely would work for Earth today. But note that to simulate observers on Earth today, you had to simulate from the big bang up to (today - light-crossing time from body) for each celestial body. That's significantly larger than Earth, only to simulate Earth today, because tomorrow the entire universe would go dark. Lightspeed gives structure to the computation of the universe but it doesn't reduce the load. Saving templates doesn't reduce the load either, not in the sense I'm considering. It may practically mean that you don't have to run it again, but theoretically if you want to know how much computation got you to this point then you have to count the computation of the templates. So if you had our whole universe at your disposal, and knowledge of all natural laws and processes, and knowledge of the starting conditions, and absolute power over matter and energy, you still cannot simulate our entire universe with anything less than just restarting it. If you wanted to simulated it specifically for some observers, you can free up resources using the lightspeed method but that's a computational debt you cannot pay if you wanted the simulation to continue.
- scoutt 6y ago
  Yes, the simulation has to have a limited duration. > Lightspeed gives structure to the computation of the universe but it doesn't reduce the load. The load would be saved because you don't need to keep computing interactions between object, because we don't get to see these object/interaction since the simulation has a limited time. You save this pre-render of the universe and you just need to calculate whatever is closer to us (and our simulated world). You don't need to calculate all at once and you don't need to calculate since the big bang, since we will experience a very short period in the simulation. And I suppose most of it can be just faked. Imagine a spherical universe with the Earth at the center. You can calculate the outer portion of the sphere, then garbage-collect, then the result is added to the calculation for an inner portion, then garbage-collect, an so on until you reach the center of the sphere. Another thing is the time-constant. Why our time has to pass with the same speed as the time outside the simulation^? What we think it takes time to calculate it's now completely relative. If time is infinite in the real universe, then they have plenty of time to build our world so effectively that our entire existence is ran in a fraction of a second. Other aspect is why our universe has to be of the same quality of the real universe. Perhaps we have a sloppy version that is easier to calculate (but it's still complex for us to understand). Of course, I'm just drinking my coffee and playing I am a genius this evening: I'm not going to defend the above as in a real analysis. Edit: ^changed calculation for simulation.