Quote:
Originally Posted by NotPrinceHamlet
I've come across a couple of websites now that have said that time is not the 4th dimension that Einstein refers to... I always thought that it is. The sites are saying that the 4th dimension is actually a spacial dimension.
E.g.
http://www.cs.unm.edu/~joel/NonEuclid/space.html |
Time is not a spatial variable.
I think the confusion arises from Special Relativity.
The metric for distance between 2 points in 3-D flat space is
ds2=dx2+dy2+dz2.
In
space-time the metric is
ds2=c2dt2-dx2-dy2-dz2 (c is the speed of light.)
ds2 is still a spatial property, but since t is now in the equation it is easy to think of t as spatial.
Steven