Kevin Wampler <nob### [at] nowherenet> wrote:
> On 7/26/2013 3:43 PM, Warp wrote:
>  >
> > Anyway, according to general relativity, spacetime *is* four-dimensional,

> Slight quibble: The 4d-spacetime stuff was already in special 
> relativity.  General relativity added gravity into the mix, but the 
> theory of 4d (Lorentzian) spacetime was there already.

> What you say is of course technically correct since general relativity 
> includes special relativity as a sub-case, but I think it's cleaner to 
> separate the two for the purposes of talking about the 4th dimension in 
> general.

But since the question was "why don't we see objects moving the fourth
dimension", talking about GR was more illustrative because according
to it, the apparent acceleration caused by gravity is in fact caused by
movement in the fourth dimension (and the nonlinearity of spacetime.)

-- 
                                                          - Warp

Post a reply to this message