Immortal Light

"This thing all things devours:
Birds, beasts, trees, flowers;
Gnaws iron, bites steel,
Grinds hard stones to meal;
Slays king, ruins town,
And beats high mountain down.
~ The Hobbit

Archimedes: Hey, you Great Old Fart, it's been too long! Where've you been?

Old Fart: I went looking for a good story to tell my good friend, Archimedes.

Archimedes: Really? You must have searched around the whole world, hoo. And for a story? I forgot what a bum you were! A bum who collects stories because he has too much time on his hands. Let me guess: You majored in folklore in college, right? I've always wondered what a person could do with a folklore degree, hoo.

Old Fart: And I see, you've still got your funny owl accent. So you'll hear me out then? Good. Let me tell you a story about time. Even you know, Archimedes, that as time goes on, we grow older. No one is immune to the decaying effect of time. But light is a different story. Light, or photons, stay young forever. Light never ages. The light that you see coming from the billions of stars in the night sky is the same light that originated from the Big Bang.

To understand why this is, we can think of driving in some open space. If we drive in a straight line at 100 mph, we will reach the end in a certain amount of time. But if we drive 30 degrees northwest 100 mph, it will take longer to reach the end because we have to divide up the speed between two directions so that the car is going x mph west and (100 - x) mph north. In the first case, all 100 mph are given to "north". In the second case, we have to divide up the 100 mph between "north" and "west". If car were to fly, we would have to distribute the 100 mph among "north", "west" and, er, "height". In other words, we are distributing the speed among the three spatial coordinates of length, width and height.

But then, consider two facts:
(1) There exists a fourth coordinate, time.
(2) The maximum speed that anything can move is c, the speed of light (300,000 m/s)

Let's make humans the base case. Humans walk really really slow, and even the fastest man in the world is not very fast at all compared to the speed of light. So most of our c is given to time. Cars can travel a little faster than humans, so a little more of c is given to the spatial coordinates and a little less to time. But still, the difference is miniscule and insignificant compared to the speed of light. Let's suppose that we are traveling in a rocket that can travel at a significant fraction of the speed of light. Then finally, we see a noticeable decrease in the amount of c given to time. The person in the rocket is aging more slowly, or traveling more slowly through time. If the rocket were going at 99% of the speed of light, then since it is traveling so fast through space, it is moving extremely slowly through time.

What if we were sitting on a beam of light? Now we are traveling through space at exactly the speed of light, and so we are not traveling through time at all! This is exactly why light, or photons, never age. Light is as old as time and as young as a newborn baby.

How about it, Archie, old boy? Didn't I tell you the Universe was a crazy old man?

Archimedes: Hoo! Didn't I tell you never to call me that? What have I ever done to you? And yes, that was a good story. Thanks, you Old Fart.

The End.