Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

How many dimensions are required minimum for an object to block light?

in 1d I doubt it's possible.

in 2d I think it could do it if only the light was limited to a dimension perpendicular to the 'thickness' dimension

in 3d I think it could do it no matter what dimension the object was looked at in.

Clarification: 3d -> A block of wood can "block light" (make a shadow) no matter how you shine light at it.

Edit: What about what are the minimum dimensions needed to block light assuming you are dealing with an $n$ dimensional space?

share|improve this question
3  
As Jim said in his answer, I don't think it's clear what you're asking. Could you clarify? –  David Z Aug 18 '12 at 2:53
    
Also depends on how many dimensions you're considering in the first place. In 1D, a 1D object would successfully "block" light, same goes for a 2D/3D object in their respective number of dimensions. –  Kitchi Nov 25 '12 at 18:38
    
Ohhhh haha interesting :). So how about the minimum number of dimensions needed to block light from $n$ dimensions? –  Eiyrioü von Kauyf Nov 26 '12 at 3:46

2 Answers 2

How about zero dimensions? A non-rotating black hole singularity is zero dimensional, It surly blocks light... :)

share|improve this answer
1  
The "black hole singularity" is not what is blocking the light. It is also not appropriate to view the singularity as the black hole source. –  Ron Maimon Aug 27 '12 at 9:03
    
blocking is trapping in this case... it is the same thing. A ray of light that its k-vector is pointing at the vicinity of the black hole singularity will get trapped in it. forever... –  natan Aug 27 '12 at 14:52
2  
I am pretty tired of repeating this: nobody knows for sure if things are trapped in black holes, I believe that for spinning and charged black holes, it just comes out later. For light, we know it just goes in and comes out from D-brane calculations by Gubser in the 1990s. Regarding the singularity, it isn't a "thing"--- the horizon is the "thing". –  Ron Maimon Aug 27 '12 at 21:05
    
This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. –  Waffle's Crazy Peanut Nov 20 '12 at 9:56

I m not sure I understand your question, but a quasi one dimensional object like a needle can absorb light or electromagnetic waves polarized in the right direction, and a parallel "forest" of needles will block "light" or waves of that polarization, but pass waves of the perpendicular polarization. I hope this partially answers your question.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.