Living in Three Dimensions? Think Again...
One of the most common misconceptions regarding the concept of spacetime is that time is the fourth dimension. Perhaps you may have heard someone make this statement before. Well, although this statement is technically true, it is only a partial truth. This misconception arises due to the tendency to consider spacetime as “space-time,” or as the familiar three spatial dimensions in which we perceive ourselves as living joined with one dimension of time. If this view is not entirely correct, then, what is really meant when physicists refer to this concept called spacetime? What is spacetime? For the purposes of this discussion, we will be talking purely about flat spacetime (also called Minkowski spacetime). What do I mean by “flat” spacetime? By “flat,” I am referring to the standard conventions of Euclidean geometry, i.e. the interior angles in a triangle sum to 180 degrees, the circumference of a circle is 2π...