|
![](/i/fill.gif) |
clipka wrote:
> Kevin Wampler schrieb:
>
>> It is worth nothing, however, that the time dimension is *not*
>> identical to the space dimensions (one would hope not!) and distances
>> are measured differently in time than in space.
>
> Well, AFAIK there's actually no fundamental reason to apply different
> "measuring tapes" to time and space: The constant vacuum speed of light
> can serve as a ruler for both, with the distance of a light second
> equating a second.
>
> It just happens that it's still more practical to use meters for
> space-like dimensions and seconds for time-like dimensions.
I think that this becomes problematic for measuring between points which
aren't connectible by a lightlike geodesic, but maybe there's some
clever way around that (although I don't see how).
In any case, I was referring to the fact that under special relativity
spacetime has a metric that differs from that of a 4D Euclidian space
along the dimension corresponding to time. For instance, the length of
a vector can be negative, which is impossible under a Euclidean metric.
Post a reply to this message
|
![](/i/fill.gif) |