Does the Fourth dimension have practical use?

The fourth dimension is part of our lives whether we like it or not. That’s because the fourth dimension is time. When you make a graph of position vs time, you have used the fourth dimension. Because our senses can only interact with one point in the fourth dimension though (the time we call now) we just don’t usually notice it.

Using the fourth dimension as it works in Einstein’s Special Theory of Relativity however is a little more involved, this is because time is affected by speed.

Basically the combined speed of any object’s motion through space and it’s motion though time is always precisely equal to the speed of light.

That’s right, everything. You, me, the computer screen you’re looking at, everything.

Everything is travelling through Spacetime: space (the three dimensions we experience) and time.

Adding the total movement through both space and time always equals light speed. Always. Always. Always.

Since you must travel constantly at exactly the speed of light, when you increase your speed through space, you decrease your speed through time.

So taking all the above in consider this.

Your head (and the rest of you) is travelling through spacetime at the speed of light. But, when you’re at rest (not accelerating) all of your head’s movement is through time, none of it is travelling (accelerating) through space. Every time your head moves (accelerates) through space; in a car, in a plane, in a spaceship… even nodding up and down, some of it’s movement in time is lost since it is now moving through space. Cool huh.

Ps. All hail to Brian Greene for the above analogy.