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All of our current theories are set in continuous spacetime. At the present, there's no reason to assume anything else.
by whatshisface 5y ago
All of our current theories are set in continuous spacetime. At the present, there's no reason to assume anything else.
- dekhn 5y agothe issue is that there are no theories based on experimental evidence at very small scales. I agree that in most situations, it would be silly to violate this assumption, unless you were working on advanced physics experiments.
- jacquesm 5y agoTrue, but we do not actually know this for sure. There is a (small) possibility that we are simply looking at this at a scale where all we see is macro effects. It would require the quanta to be much smaller than the Planck distance though.
- webmaven 5y ago> There is a (small) possibility that we are simply looking at this at a scale where all we see is macro effects. It would require the quanta to be much smaller than the Planck distance though. How much smaller?
- jacquesm 5y agoMany orders of magnitude. How many? I do not know, I don't think anybody does. But photons resulting from the same event but with different energies arrive at detectors an appreciable distance away to all intents and purposes simultaneously, something that would not happen if spacetime were discrete at a level close to the Planck length. So it would have to be quite a big difference for an effect not to show up as a difference in time-of-flight.
- aeternum 5y agoIs the idea that the two photons would traverse slightly different voxels due to the lower frequency wave being more spread out? What accounts for the expectation that they do not arrive simultaneously in a voxel-based universe?
- feoren 5y agoI wouldn't say that "all our current theories" are set in continuous spacetime. For example, Quantum chromodynamics is set in SU(3), an 8-dimensional group of rotation-like matrices. Electric charge is discrete, spin is discrete, electron orbitals are discrete. In fact position and momentum would seem to be the outlier if they were not also discrete. I hardly call that "no reason".
- whatshisface 5y agoSU(3) is a continuous group.
- freemint 5y agoYeah but it is very much not in space time.
- whatshisface 5y agoBut it is. SU(3) is the group for swapping colors around. It still has spacetime.
- freemint 5y agoYou can Cartesian product it with space time, yes. But that is possible for any system.
- whatshisface 5y agoI'm having a hard time imagining quantum chromodynamics set in a single point. :)
- drdeca 5y agoIt is based on SU(3), but, does it really make sense to say that it isn't still set in spacetime? Like, quarks still have position operators, yes?