spacetime

And then one should question as to whether or not they want to believe with any fervor that spacetime has a physical sense.

Maybe there are other channels of exploring spacetime than just the physical reality.

However since our 4D spacetime is not Euclidian but Minkowskian the sign in the generalised Pythagoras theorem is a minus and not a plus.

We don't know what spacetime is made of, or what you can do with the things it's made of, or what their properties are.

As I read that, I felt it was a bit too strong - isn't the issue whether spacetime have an independent physical sense?

We need to work out how to bend spacetime.

I would say even if he had heard of or read about real science regarding spacetime, he wouldn't even have been able to understand it anyway.

>And then one should question as to whether or not they want to believe with any fervor that spacetime has a physical sense.

Due to the expansion of spacetime during those 25,000 years, we would have slightly longer than 1 minute to receive the signal, but it would be so insignificant that you might as well call it a minute.

Since (in the Noether theorem sense [2]) energy is the conserved quantity related to symmetry of displacements in time and momentum is the conserved quantity related to symmetry under displacements in space, it is quite natural to unite them into one four vector, related to symmetry of displacements in spacetime.

Is the reason you say that a consequence of relativity theory is that time isn't exactly a property of the universe because the 4 variables of spacetime are all distances [(c*t, x, y, z)] as opposed to having 3 variables being distances and one time [(t, x, y, z)]?

> Is the reason you say that a consequence of relativity theory is that time isn't exactly a property of the universe because the 4 variables of spacetime are all distances [(c*t, x, y, z)] as opposed to having 3 variables being distances and one time [(t, x, y, z)]?

That is, if you spend too much time implementing a feature "perfectly", that is not perfect in the 4D spacetime continuum.

The mathematical models of space and time suggest that there might be a philosophical stance where "spacetime" itself is a physical object.

And we are not even in the beginning of understanding what "spacetime" _really_ is.

The problem with this POV is that "internally" we're only able to perceive certain things and, indeed, these things are ignorant to changes in spacetime configuration.

Spacetime.tv works for me when I connect two browser windows to make a game.