Try to envision a universe with nine spatial dimensions and one dimension of time. Such is the emerging view of our universe according to String Theory. Or, if you prefer the closely related M-theory, you will have to live with a universe of ten spatial dimensions and one of time.
I used to lie awake nights pondering where the extra dimensions were to be found. I would concentrate on a corner of the room, where two walls and the ceiling met, and try to envision a fourth spatial dimension. Our whole world view of normal space is constricted to three spatial dimensions, length, width and height. Trying to envision anything beyond those is very difficult.
But the extra spatial dimensions are not like the familiar width, length and height. Rather, they seem to be curled up inside of ordinary space as the image above suggests. They are closer to us than our own skin, and yet the open up to the very edges of our universe and perhaps beyond.
To envision String Theory, we must leave behind our normal concepts of space. Normal space that is bound by boxes demarcated by width, length and height. String Theory does not involve a fourth or fifth box dimension, but something much more exciting.
Think of the extra dimensions not as spaces but as channels or conduits. Our houses are not just boxes stacked together. What makes our houses actually work are the conduits that supply us with water, electricity, heating and cooling, and connectivity. When we flip a light switch, we expect the light to come on. We do not need to know the location of the electrical wiring, and so we do not even think about it.
Of course one could argue that these conduits are simply small boxes hidden within the big boxes of the house, and that would be technically correct. An electrical cable actually does have dimensions, and does occupy specific spaces within the walls, ceilings and floors of the house. But there are no dimensions to a Wi-Fi signal. There is no wiring schematic to show where the WI-Fi signal runs. It seems not to exist in ordinary space. Because Wi-Fi is totally disembodied, it makes an even better analogy for extra dimensions.
For most of human history, if you wanted to send a message a long distance, you would have to entrust it to a human (or string of humans), who would bodily carry the letter to its destination. A human being, moving under her or his own power, can cover something like 32 kilometers (20 miles) per day, and that assumes the most optimal terrain an weather conditions. At the end of the War of 1812, hostilities continued for more than sixty days after the war had officially ended because of the difficulties in spreading word of the wars ending to remote frontier regions.
Radio communications were as much a part of the universe back then as they are now. The problem was that the combatant in 1812 lacked the understanding of radio as well as any technological infrastructure to exploit it.
Today is a much different world. It is now possible for a person in Nome, Alaska to play a chess game with someone from Pretoria, South Africa, and to conclude that game real-time within in five or ten minutes. In the old days it would have taken many years of postal chess, where one move at a time would have been mailed from one participant to another, with each move requiring weeks or even months to arrive at its destination. We have achieved on this planet a state of simultaneity. And what I mean by that is that whatever happens at any place on the planet is now knows instantly across the whole planet, or at least in those places that have the technological infrastructure to tap into the planetary communications grid.
But once we leave the confines of this planet, that state of simultaneity vanishes. On earth, light speed communication counts as instantaneous, as radio waves can circle our planet seven-and-one-half times in one second. As we reach out into space, even a signal to Mars can take up to forty-five minutes. There is no need for a message to Curiosity telling it to, “Look out for that rock!” because by the time the message gets there, the rock will be just a distant memory.
Captain Kirk could always call Star Fleet Headquarters on “sub-space” communications links.
Now back to String Theory. What if some of these extra dimensions could provide us with simultaneity throughout the universe? This unfamiliar concept would totally change our society, not to mention our conception of the universe.
Think of two stars that are 10,000 light years apart. Now let us assume that both have civilizations and that both of these civilizations construct radio telescopes at the same time. Can we call this a simultaneous event? I think not because these two civilizations are not aware of each other’s presence. It also works to say that they are not aware of each other’s presents. Because of the messaging time, neither could be aware of the other’s existence for at least 10,000 years. A signal followed by a response would take at least 20,000 years. After such a long time interval one or both of those civilizations could have died out, or have been pushed back into the Stone Age.
Civilization on earth has only been around for 10,000 years. Civilization refers to the creation of walled cities, the development of agriculture, and the creation of writing and mathematics. The earth has had radio telescopes for only 100 years, and really good ones for about 50 years. While radio has been around since the late 19th Century, there was not much in the way of outbound radio messaging that could be intercepted in other star systems until World War II. Thus, our messages have been streaming out for only about sixty years to star systems in a sphere with a 60 light year radius. The Milky Way Galaxy has a radius of some 60,000 light years.
Now, let us suppose that String Theory allows for one or more of the extra dimensions to function as a channel or conduit through which connectivity is possible. Imagine if these two civilizations could sit down for a friendly game of chess in real time.
Somehow logic demands that there be universal simultaneity. We have just not discovered the technology to understand and exploit that technology. String Theory gives us at least the possibility of knowing what is happening on Proxima Centauri right now, without the need to wait 4.2 years to receive the message via light waves.