### spacetime diagram

**(Minkowski diagram)**
(graph of simplified spacetime, with fewer space dimensions)

A **spacetime diagram** (or **Minkowski diagram**) is a graph of a
simplified spacetime which can be used to demonstrate consequences
of relativity. It is a 2-dimensional graph showing only a
single dimension of space, i.e., a planar "cut" through 4-dimensional
spacetime. (A variant on such a diagram is a 3-dimensional graph
that shows two space dimensions.) Typically, time is represented
as the vertical axis.

Typically the graph is scaled so the path light would take along
this dimension shows as a 45-degree angle. Lines steeper but not
vertical can represent objects, i.e., **time-like**, lines, and lines
less steep are impossible to traverse (**space-like**).
Variations on the graph, including rotating axes, can be used to
demonstrate effect of differing frames of reference.

(*diagram,relativity,cosmology,black holes*)
http://en.wikipedia.org/wiki/Minkowski_diagram

**Referenced by:**

worldline

index