10k views

### Why are extra dimensions necessary?

Some theories have more than 4 dimensions of spacetime. But we only observe 4 spacetime dimensions in the real world, cf. e.g. this Phys.SE post. Why are the theories (e.g. string theory) that ...
939 views

### Measuring extra-dimensions

I have read and heard in a number of places that extra dimension might be as big as $x$ mm. What I'm wondering is the following: How is length assigned to these extra dimensions? I mean you can ...
4k views

### What could we observe if we see a 4 dimensional object and how could it change our physics view about our universe?

My question is little bit philosophical. I would like to explain my ideas with a 2 dimensional universe model. If we had lived in 2 dimensional universe like a plane, What could we observe when ...
12k views

### Have we proven that higher dimensions exist? [duplicate]

Have we proven higher dimensions exist?
8k views

### Can we actually prove with 100% certainty that there are more than 3 dimensions plus time $(t,x,y,z)$? [duplicate]

Can we actually prove with 100% accuracy that there are more than 3 dimensions plus time? In the news there are always articles like "there are probably 7, 11 or more dimensions", "time is actually ...
445 views

### Do multiple dimensions exist? [duplicate]

I came up with this line somewhere: To properly experience $n$ dimensions the retina of the organism should be at least of $n-1$ dimensions. And human eye has $2$ dimensional retina, so we can ...
89 views

### How can we be sure that there are only four dimensions? [duplicate]

Infants can only perceive in one dimension (closeness and farness). Young children can only perceive three dimensions (they can't plan or handle time). Teenagers and young adults can perceive 3+1 ...
87 views

### Does nature have more than four dimensions? [duplicate]

Does nature have more than four spacetime dimensions? If so, what is their size? Are dimensions a fundamental property of the universe or an emergent result of other physical laws? Can we ...
Modern pop culture would have us believe that there is such a thing as the 4th spatial dimension. And yes it's easily shown that $n$ dimensions is possible using math alone and 3 just happens to be ...