Soo what are you wondering? I’d expect it’s obvious in our everyday experience that time is a bit different from space.
If you want a something more mathematical, pick an equation from physics. It probably treats time separately from space. The only kind-of exception I can think of is general relativity, and even it ends up producing metrics that give time the opposite sign, like the flat space example the other poster mentioned.
The directionality of time is a bit more subtle and emergent, but you don’t need it to look at a double light cone and observe that while a slice of it is a sphere, the whole thing is not a hypersphere. That just follows from Maxwell’s equations or the other wave equations in nature.
If somebody here knows their way around QFT they might have something to add, but for all the rest it’s just kind of built in.
Soo what are you wondering? I’d expect it’s obvious in our everyday experience that time is a bit different from space.
If you want a something more mathematical, pick an equation from physics. It probably treats time separately from space. The only kind-of exception I can think of is general relativity, and even it ends up producing metrics that give time the opposite sign, like the flat space example the other poster mentioned.
The directionality of time is a bit more subtle and emergent, but you don’t need it to look at a double light cone and observe that while a slice of it is a sphere, the whole thing is not a hypersphere. That just follows from Maxwell’s equations or the other wave equations in nature.
If somebody here knows their way around QFT they might have something to add, but for all the rest it’s just kind of built in.