Is space is continuous or discrete?

  • #1

Main Question or Discussion Point

I was watching a video where well known physicist Lisa Randall said that we still don't know whether space is continuous or discrete.

My question is, how do we find whether space is continuous or discrete?? What type of experiments are possible? Is it being done now??

I am thinking this may be connected to elementary particles. So, I am thinking like this: Space will be discrete if we ever found a particle that cannot be divided further. But then that particle also resides inside space, so how can we tell that SPACE is discrete??

How do we do it?
 

Answers and Replies

  • #2
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String theorists might argue that space occupied by the theoretical strings is a discrete bit of space.
While string theory looks good mathematically, we have no technology at present which could validate the idea.
 
  • #3
sophiecentaur
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What type of experiments are possible?
From what I have read, the Energy needed to prove or disprove this is way in excess of what they can use in CERN etc.. I imagine that the answer may lie in observations of extreme events in deep space.
 
  • #4
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Space will be discrete if we ever found a particle that cannot be divided further.
We've found several kinds of particles that, as far as we know, cannot be divided further - electrons, for example. It doesn't follow that space is discrete.
 
  • #5
From what I have read, the Energy needed to prove or disprove this is way in excess of what they can use in CERN etc.. I imagine that the answer may lie in observations of extreme events in deep space.
So, what is the experiment we can do if we assume we have this enormous energy??
 
  • #6
sophiecentaur
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So, what is the experiment we can do if we assume we have this enormous energy??
No idea but do most of us really understand how things like the Higgs Boson are detected by CERN? It's based on looking at the various energies of the products of high energy collisions. Higgs predicted a presence at a certain energy and they found it.
Perhaps looking for a variations in some of the expected spectra of very high energy products could imply spatial quantisation. On a very humdrum level, you can detect periodic variations along an RF feeder line by looking at the frequency response (it behaves like a temporal filter). However it's done (if ever) it will be very subtle on top of very subtle!
 
  • #7
I thought [according to Sean Carrol et al] that particles don't exist - they are all perturbations in various fields..
 
  • #8
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I thought [according to Sean Carrol et al] that particles don't exist - they are all perturbations in various fields..
These perturbations exist. These perturbations are particles. Therefore, particles exist. They just don't behave the way that our classical intuition, based on a lifetime of experience with bullets, beads, and other small solid objects, expects.

However, further discussion of what particles are is off-topic here and belongs in a thread of its own - but please review some of the many threads on this subject that we already have before starting a new one.
 
  • #9
These perturbations exist. These perturbations are particles. Therefore, particles exist. They just don't behave the way that our classical intuition, based on a lifetime of experience with bullets, beads, and other small solid objects, expects.
However, further discussion of what particles are is off-topic here and belongs in a thread of its own - but please review some of the many threads on this subject that we already have before starting a new one.
Back on topic, as 'particles' are perturbations or mathematical snapshots of field vibrations I tend to think that space/spacetime is continuous or the universe is 'one'. Saying something is 'discrete' is a question of linguistics; language is discrete and uses atomic chunks [nouns etc] so we naturally attach labels to everything so we can process concepts and communicate. To 'know' is to atomise something into pieces which are then themselves believed to be 'real' or discrete. We need some sort of linguistic calculus to unpick it all.
 
  • #10
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Saying something is 'discrete' is a question of linguistics; language is discrete and uses atomic chunks [nouns etc] so we naturally attach labels to everything so we can process concepts and communicate. To 'know' is to atomise something into pieces which are then themselves believed to be 'real' or discrete. We need some sort of linguistic calculus to unpick it all.
Sorry, but it doesn't make sense and has nothing to do with physics.
 

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