I used to believe infinity extended in all directions: outward into space and inward into the tiniest particles, from the past into the future, backward and forward in the reflections of a mirror reflecting a mirror, and around and around a circle. However, now I suspect that “infinity” means little more than “goes a very long ways.”
If you keep following a circle or a figure eight (the symbol of infinity) around and around, the shapes seems to go on forever, but who could follow them forever? Someone with Obsessive Compulsive Disorder on the very best crack could only follow the symbol around and around for a couple days at most. Once the crackhead stopped tracing the shape, the eternal symbol would cease to be eternal. A circle and a figure eight do not go around and around forever. They just sit there. Only our eyes go round and round.
A mirror reflecting a mirror seems to recede into eternity, only — you may have noticed — you can never quite look at that eternal point. The hallway of reflected mirrors always curves out of sight. The reason? Your eye is always in the way. Your eye would need to be in the exact center of two perfectly parallel mirrors to see the so-called infinite regression, but your eye would scoop up the light and break the sequence. Let’s imagine an eye at that perfect center that can somehow see but which does not stop the light. Wouldn’t the reflections keep going forever? No, at some point, the light would be down to a single photon and that photon cannot get any smaller. There seems to be a limit to smallness. The photon would keep bouncing back and forth until it was refracted by the air or absorbed by an atom, but it would not carry the image of a mirror any longer.
When I thought that space was infinite, it pleased me to think that I was at the very center, since any point of an infinite space can be called the center. However, when scientists say that “Space is expanding,” they are suggesting that space is finite. Infinity cannot get any bigger. Only something of a limited size can grow. Scientists discovered that the universe was expanding when they noticed a red shift in the light from stars, especially the most distant stars. When an object moving away from the viewer emits light, the wavelengths get stretched, giving the light a reddish tint. When such an object is moving toward the viewer, the wavelengths get squished and appear bluish. Not only is the universe expanding, but the rate of expansion is accelerating.
You may wonder, “If space is limited, what exists outside of space?” You may imagine yourself approaching the limits of the universe in a spacecraft moving at warp 250,000, but if space is curved, you would never reach the edge; your course would turn and you would continue traveling through space until your dilithium crystals were drained. You would not, could not travel forever, even in an imaginary spaceship.
You may also picture yourself, godlike, sitting outside of the universe watching it blow up like a balloon, but if you think this way, you are thinking in spatial terms. There is no space outside space. There are no seats outside of the game. You need to move your mental eye inside the stadium. Space is not an eternal emptiness which the universe expands into. Space is itself a thing, like a fabric, that came into existence during the big bang.
We tend to picture the big bang from the outside (as in the picture to the right), like we are observers watching fireworks on the fourth of July, but this is a mistake. Again, there is no outside. Another problem with this conception is that we cannot start watching before the explosion happens, because there was no “before.” There was no time before the big bang. Time, like space, was something that came into existence. To more accurately picture the big bang, place your imaginary eye in the center of the singularity at the moment of hyperinflation and watch the universe expand outward from you. (Of course, there would be no light yet, but we are using imagination after all, so we can allow ourselves some liberties.)
Will the universe eventually slow down and contract back in upon itself, crushing all matter and energy back into another point, a singularity where all the known laws of the universe break down? Will a new universe be born? Or will the universe keep expanding forever? Current evidence suggests that it will keep expanding until all the energy has dissipated. Since matter is energy in its most basic form (if I understand the physics right), then all matter would eventually fizzle out. Would this dark universe continue indefinitely or would space and time, which are also things, fade out of existence?
The future is perhaps the only direction that might continue indefinitely, but I doubt it. I find myself hoping that the universe will contract and be reborn again, but why do I care so much when I can only a tiny, tiny fraction of the life of my own star, much less my galaxy? Why do I want so much to believe in infinity? I do not even use all the space in my small apartment, but somehow the idea of infinity gives me more breathing room. Infinity is a pleasing fantasy. Although I am finite, something is not.