- #36

Mister T

Science Advisor

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You are over-thinking the concepts here. Take a tape measure and measure the distance between two locations. That's the amount of space between them. Take a stop watch and measure the amount of time that passes between two events. That's the amount of time between them.Wiredcerebellum said:But if space is literally the absence of matter or physical properties, and time has no physical properties, how do the two merge to form the 4-dimensional structure called spacetime?

Just as when you use something like the Pythagorean theorem you can calculate a distance knowing two or three different dimensions. ##r=\sqrt{(x^2+y^2+z^2)}##. You're using Euclidean geometry.

There are other types of geometry. It's useful to use time as a dimension when doing calculations in relativity. You calculate something called the interval, for example a spacelike interval would be ##s=\sqrt{(x^2+y^2+z^2-t^2)}##.

In your mind you have somehow misconstrued the concept, like by reading popsci books or articles rather than studying the physics. There are no shortcuts to understanding, popsci accounts attempt to create a shortcut to learning but they often have the opposite effect.