- Jeffrey KLv 65 months agoFavorite Answer
A 4 dimensional manifold with 3 dimensions of space and 1 dimension of time. Its metric is
dS^2 = dx^2 + dy^2 + dz^2 - dt^2
Notice the minus sign before the time term. This is the only thing that makes time different from space.
- Barkley HoundLv 75 months ago
It is a name for the first 4 dimensions.
- MorningfoxLv 75 months ago
Spacetime = space + time. Or mathematically, space^2 - time^2.
- Steven SLv 75 months ago
Trust me. Just look it up.