What Is Minkowski Spacetime?

This section provides a quick introduction on Minkowski spacetime, a 4-dimentional spacetime coordinate system used with a frame of reference to mathematically describe the special theory of relativity.

What Is Minkowski Spacetime?? Minkowski spacetime is a 4-dimentional spacetime coordinate system named after the mathematician Hermann Minkowski. Minkowski spacetime is the most convenient coordinate system used with a frame of reference to mathematically describe the special theory of relativity.

Minkowski spacetime has the following main assumptions:

4 axes (t,x,y,z) are mutually orthogonal.

The distance (or interval), s, between two points (or events) is defined as:

```s = sqrt(-(c*dt)**2+dx**2+dy**2+dz**2)      #1: Minkowski interval
# c is the speed of light
# dt, dx, dy, and dz are coordinate differences of the two points
```

Notice that the time component has a negative sign different than space components in the definition. This is an important contribution from Hermann Minkowski in constructing spacetime mathematical models. Distance is no longer a non-negative number. It is not even a real number in case where (c*dt)**2 > (dx**2+dy**2+dz**2).

If we simplify a Minkowski spacetime by dropping y and z dimensions and scale the time axis as c*t, we can illustrate the interval of two events as shown in the diagram below: