Is space currently thought of as discrete or continuous?

[Credulous]

I was wondering what the majority opinion was on this issue, among physicists and philosophers as well. I can't imagine zooming in a million times smaller than the plank length and still not being at a smallest length, however a discrete universe doesn't make much sense to me.

Are there any known consequences or effects of the universe being discrete versus continuous? Would there be a measurable effect?

 

[mkillman]

To be honest that is a really big can of worms and with no definitive answer.
I guess we will never know until someone successfully hits "the end of the universe" as it were I heard there is a great resturant there to

 

[zhermes]

In both general relativity and the standard model, space-time is always continuous. Thus, the standard, excepted picture is continuous. There are many indications (namely from quantum mechanics) that space-time might be quantized at the Planck-scale, as is described by theories like loop quantum gravity, and (at least much of) string theory.

 

[bohm2]

There are suggestions that spacetime might be something that emerges from a non-spatio-temporal and more "fundamental" level but it isn't clear what one means by "emergence". A recent, short philosophical paper on this topic can be found below with some interesting quotes. The section "Emergence in what sense" is an interesting section:

Quantum entanglement and thus the non-separability of the entities subject to the entanglement is independent of the distance of these entities in space. But this fact does not justify the conclusion that non-separability somehow exists outside spacetime or, in other words, that the relations of quantum entanglement are somehow ontologically more fundamental than the metrical relations that make up spacetime. For it seems that there is no sense in which there could be concrete physical structures of entanglement (concrete relations of non-separability) unless they are implemented or instantiated in spacetime. Furthermore, as mentioned above, the commitment to quantum entanglement and non-separability implies the commitment to a non-local dynamics, whereby the dynamics being non-local entails that it applies to entities in spacetime.

Indeed, there are two interrelated sets of problems for the idea of the ontological emergence of spacetime from a non-spatio-temporal level in canonical QG. First, the very notion of concrete physical entities that are not spatio-temporally extended needs to be clarified. In the face of the above discussion, a specification in terms of quantum structures does not play the right role (since according to the main interpretations, quantum structures need to be implemented in spacetime in order to be concrete physical structures by contrast to abstract mathematical ones). Second, it is doubtful whether any precise notion of ontological emergence is available in this context. In particular, no account is given how it could be possible that decoherence – being conceived as a process that is not in (space)time and that concerns entities which are supposed to exist independently of spacetime – can produce the required spatiotemporal picture involving local beables.

A dilemma for the emergence of spacetime in canonical quantum gravity
http://philsci-archive.pitt.edu/9074/

I'm guessing some physicists like N. Gisin would probably disagree somewhat with first quote (?) because he does argue in some of his papers that, in fact,

nonlocal quantum correlations (do) seem to emerge, somehow, from outside space-time.

Quantum nonlocality: How does Nature perform the trick?
http://lanl.arxiv.org/pdf/0912.1475.pdf

Are There Quantum Effects Coming from Outside Space-time? Nonlocality, free will and "no many-worlds"
http://lanl.arxiv.org/pdf/1011.3440.pdf

 

[sardar]

I can tell you that the current understanding of space is that it is continuous rather than discrete. This means that it is not made up of individual, separate units, but rather is a smooth and uninterrupted fabric. However, this understanding is constantly evolving and there are still ongoing debates and discussions among physicists and philosophers about the nature of space.

One reason for the belief in a continuous space is that it is supported by the theories of relativity and quantum mechanics, which have been extensively tested and confirmed through experiments. These theories suggest that space is not made up of discrete units, but rather is a continuous and dynamic entity.

On the other hand, there are some theories, such as loop quantum gravity, that propose a discrete structure of space. However, these theories are still being developed and have not yet been fully tested.

In terms of consequences or effects of a discrete versus continuous universe, there are some potential implications. For example, a discrete universe could potentially lead to a different understanding of time and causality. It could also have implications for our understanding of black holes and the behavior of matter at very small scales.

However, as of now, there is no concrete evidence or measurable effects that can definitively prove one theory over the other. Further research and experimentation are needed to gain a deeper understanding of the nature of space.