Before this thread goes any further, you undergrads need to get one thing straight
>>1147>>1276Dimensions are whatever the hell you want them to be. We often make velocity a dimension in phase space. We can make momentum a dimension if we want.
Dimensions are not physical things, they are mathematical tools. There is no "4th" dimension (as this guy was pointing out
>>1198) just as there is no "1st" dimension.
One other source of confusing might be that when someone talks about "the dimension" of a particular space they are talking about the number. i.e. the space we occupy is of dimension 3, a plane is of dimension 2, etc..
So saying things like
>And no, it isn't timemakes it sound like you're under the impression that dimensions are fixed, as if there is a "4th dimension" somewhere out there in the universe and scientists are trying to find it.
If you want to consider a 4-dimensional space then you simply say you have 4 dimensions (talking about which is the 4th is pointless).
If you want to have a 3-dimensional space with 1 dimension of time then you can do that too. You can also have a 7 dimensional space with 2 dimensions of time if you want.