I will start my first blog with a short tale to demonstrate what this is about.
Let's embark upon a journey to the edge of the known universe. We begin in our hypothetical ship as it orbits the Earth. Engaging an extradimensional drive, we are seemingly able to exceed the speed of light at a rate of thousands of lightyears per minute. (I understand that this is currently believed to be impossible so just bear with me. This is only to make a few points.) The reason we need such speed is that we want to reach the edge of what is visible from Earth in a fairly reasonable time. The direction we choose will take us past several familiar galaxies once we leave our own Milky Way Galaxy. We pass by the Great Spiral Galaxy in Andromeda after about 1 hour at that speed. This is approximately 2.3 million lightyears away. Continuing on in the same direction, we are headed for a tiny point of light that can only be seen using the most powerful telescopes back at the planet Earth. Already, however, we are seeing something beyond that.
We travel for several weeks in the same direction until we reach the 13.6 billion lightyear distance that is visible from Earth.If we look back, Earth will be just within our visual range. This is the limit of our visual capability, since this is the greatest distance light has traveled thus far in the universe that we know.
What do we see when we get there? More of the same things we have been seeing throughout the journey. Galaxies stretching further into space beyond what can be seen from Earth. And yes they are rushing away from each other just as we see them doing from our place on Earth. It seems that the mysterious "Dark Energy" is at work here as well. (I am addressing the existence of this supposed "Dark Energy" as well.)
We decide to continue on to see if there is an edge to the universe. We go and go, always finding more of the same as we go. Eventually after several years of travel in this direction at this speed we find that the matter of the universe we can see is growing ever thinner and more spread out. Soon we reach the edge of all known matter in the universe. We look outward to see what may be beyond all that matter. We see black empty space. Our ship is still feeling a tug of gravity from that direction, however!
We travel for several more years, into our own old age. Trillions of lightyears are traversed. It seems we cannot find the source of the gravity that is obviously there, but soon enough, we do find it. It is another super sized collection of matter in the universe made up of trillions of galaxies similar to that we left behind. And if we could live long enough, we would continue to find more of the same.
Now, what is the point of all of this? Well to explain, I will need to point out what many scientists currently believe about the universe.
1. Many think the universe is finite but expanding. They point to the fact that all the galaxies are rushing away from each other at a faster and faster rate. In other words, it is all accelerating away. They believe that space itself is expanding.
2. They have theorized the existence of "Dark Energy" as the force that is driving the acceleration of all galaxies away from each other. As of yet they have been unable to detect this energy, however.
3. Some say that space itself curves back on itself, so that a beam of light that left its source will sometime in the extremely distant future return to its source's original location, (barring the effects of gravity and barriers it may be unable to pass through.
Here are my thoughts concerning these things:
A. The universe is infinite! Why do I believe this? Because to say that something has an edge or end is to say that something exists that is beyond that edge or end. It is not possible for it to be any other way. Just imagine that you are running in a field. All that you know is what you can see in that field. you come to the edge of the field and you stop, fearing to go further because you don't know what is beyond that edge. You can see however that there is something there on the other side of that edge. Then you realize that if there was nothing there, not even space, it would be far more impossible to comprehend. My point is that space goes on forever without end, and although there may be nothing in it, it is still part of the universe. Why? Because the actual definition of the word universe is all that exists. Even empty space is something that exists, and that makes it part of the universe. You may want to ask about the "Multiverse Theory" that says there could be many universes existing on separate planes of existence. I do not call them other universes, however. Instead, a more sensible name for the other planes of existence if they truly exist is "Continuum". They would also be part of the "All That Exists" or "universe".
B. There is no true evidence of the existence of "Dark Energy". The fact that all of the galaxies in the observable universe are rushing away from each other can be explained in a much simpler way. I'm not saying this is how it is actually happening, but this scenario makes more sense to me. Think about what would happen if you put a small amount of compressed air into the center of a vast room that is a perfect vacuum. Say the amount of air is only 1 gram in mass, and the vacuum is the size of the Earth in volume. What happens? The gram of air will begin to expand outward at a faster and faster rate until it fills the entire space of the vacuum somewhat evenly. Now apply this principle to the universe that is infinite. At certain areas in the universe and event occurs that introduces matter into that area. It rapidly begins to expand outward, trying to fill the surrounding vacuum. As it continues to expand the matter grows thinner the more volume it fills and this causes it to accelerate, getting faster and faster as it fills more volume. In this scenario, however, the vacuum is infinite in size, so the expansion will continue to accelerate forever. Seems impossible? Perhaps, but if there is our own collection of matter which we know, it stands to reason that there must be others as well and all of them are trying to help fill the vast endless vacuum of the universe. Eventually they will merge with others and expand as one.
C. Curved space might actually exist, but it does not preclude the infinity of the universe. As a curve continues to move through its arch, you begin to wonder "What if I could step outside the curvature of my current space?" The fact is that you can, and that area that is outside that curve is yet more space. If space is curved, it must be made up of an infinite amount of curves that are being realized through every possible direction, angle, and plane of existence. An infinite looping effect that proves beyond a shadow of a doubt that the universe is infinite.
So is the universe infinite? To me it is the only thing that makes any sense. As much as I have tried to imagine a finite universe, I have been unable to do so. The questions always come up "What is outside of that universe?" and "Wouldn't that also be part of the Universe?" And the answer to the last question is that if the definition of the word "universe" is "All that exists." then anything that is outside of a finite area called the universe must be included, and is thus part or that universe! And anything outside of that, and so forth and forever.
