Thrawn Rickle 81TIME WAITS FOR NO MAN© 2004 Williscroft |
Isaac Newton defined how we think of time: as a flowing river moving at constant speed from the past to the future, never deviating, never changing. We are born, we live, we die. A tree is planted, grows, is felled, cut up, and becomes a house. Snow and rain fall in the mountains, gather into brooks and streams, merge into rivers that flow into oceans. Tectonic plates collide, mountains emerge, are assaulted by wind, rain, and rising water, and eventually erode back to the plains from which they arose. Time is one-way, an arrow, immutable in its inexorable progress…or so it seems. When Albert Einstein published his Special and General Theories of Relativity in the early 1900s, he said to the world, “Wait a moment. Time is not so constant as Newton said; it meanders, and speeds up and slows down around stars and galaxies.” We came to think of time as just another dimension in a four-dimensional space-time continuum. We began to understand that time’s flow is entirely dependent on our own motion through the other three dimensions. We even discovered that we could use this new knowledge to improve our lives through the application of modern physics and its step-child, electronics. Through all of this new understanding, however, time still flowed in one direction. True, it meandered a bit, and speeded up and slowed, depending on circumstances, but it only went that way, towards the future. In 1949 Kurt Gödel decided to spend some quality time reviewing Einstein’s relativity equations. To put this event into context, you should know that Gödel was arguably the finest mathematician and logician of the last millennium. When he tackled Einstein’s General Relativity equations, he discovered a solution that had eluded Einstein. Einstein’s solutions describe an expanding universe in which time flows only one way, albeit with turns and speed variations. Gödel’s solution describes a rotating universe where time twists back on itself, so that if somehow you were to go all the way around the universe, you would arrive back where you started before you got underway. In Gödel’s universe, time has whirlpools, which scientists call “closed time-like curves.” Einstein was not happy with several developments that flowed from his original work with Relativity. He was especially bothered by the implications of the Heisenberg Uncertainty Principle which says, in effect, that on the very small scale, it is impossible to know for a particle both its exact position and the precise time it was in that position, which forces researchers to deal with very small things statistically. He said, “The Old One [God] doesn’t roll dice,” and insisted that ultimately things still were deterministic, that they were ruled by cause and effect. Similarly, Einstein was unhappy with Gödel’s universe. He dismissed these solutions on physical grounds, since it was “obvious” that the universe expands; it doesn’t rotate. But Gödel had opened the barn door, and the horse had left at full gallop. Scientists went back to examine earlier solutions to Einstein’s Relativity equations, and discovered W.J. van Stockum’s work on infinitely long spinning cylinders – picture a very long spinning maypole. It turns out that if you dance around it, like with Gödel, you get back before you start. Then in 1963, mathematician Roy Kerr discovered that if you collapse a spinning black hole (and they all do spin), you don’t get a singularity as everyone thought, but a ring of collapsed matter called a wormhole. And when you pass through the ring, you end up in the past, or somewhere else in this universe, or in another universe altogether. The problem was that for physical things, the passage would be destructively traumatic – whatever went in would exit as mush. In the 1980s, Kip Thorn and his Cal Tech colleagues discovered another class of solutions to Einstein’s equations that got rid of the mush factor. It appeared, after all, that structured matter - like machines and humans - could transit wormholes under certain circumstances, and even return, kind of like an elevator through time. All that is necessary, it seems, is to find a wormhole with the correct entry and exit points, and expand and stabilize it so that it can be used. To do this takes a lot of power, a LOT of power. First, let’s look at the wormholes. According to modern theoretical physics, at very short distances - around 10^{-33} centimeters – space becomes “foamy,” consisting of countless wormholes and other virtual particles that pop into and out of existence. It turns out that this popping into and out of existence, this churning effect, creates a “negative energy” that we can use to stabilize any particular wormhole. Here’s how it works. The effect of virtual things popping into and out of existence at this level is a “pressure” analogous to atmospheric pressure. Two plates positioned very, very close together (but not touching) are in a zero energy state, because nothing moves. If we set up the conditions properly, these zero-energy state plates will experience a higher “pressure” on the outside surfaces than on the inside surfaces, and they will collapse. Since they started out at a zero-energy state, while collapsing they enter a lower or negative energy state, called the Casimir Effect. It sounds like fantasy, but the Casimir Effect is real, measurable, and can be used under the right circumstances to stabilize a wormhole. The problem is harnessing sufficient energy to bring this whole scenario about in the first place. We’re talking about energy levels on the order of that produced by a star, something we are not even remotely capable of doing today. But it’s not impossible. One can imagine a civilization sufficiently advanced that it can generate such energy levels. These guys would be able to manipulate space-time itself, and to move about within space-time in ways we cannot even imagine. The capability to move through time, no matter how remote, raises the conundrum of paradoxes: Going back in time, killing your grandparents, so that you cannot be born, and so can’t go back in time in the first place, which means your grandparents were not killed, which means… Imagine a wormhole so positioned that the entrance and exit are near each other, and where the entrance is in the “present,” whereas the exit is a second or so in the “future.” Now imagine shooting a billiard ball into the entrance at such an angle that the exiting ball (the same one) will strike itself on its path towards the entrance, deflecting it from entering the wormhole in the first place. Kip Thorn and colleagues have calculated that there simply is no angle where this can happen. Every possible angle causes the exiting ball to miss the ball rolling towards the entrance. In this instance, at least, the universe absolutely prevents a paradox. Nevertheless, we still are faced with the consequences of killing the grandparent, since one can imagine no method of “preventing” the action that does not require intervention of something or someone. String theory, which is the current explanation of how the universe really works, supplies an interesting answer. In this approach, every time a “decision” is made, the universe branches or splits into two separate time lines, something that happens countless trillions of times each microsecond. This results in a “multiverse” with virtually infinite branches that are multiplying with bewildering speed at a hyper-exponential rate. In this scenario, time travel is not back and forth movement in Newton’s or even Einstein’s river of time, but rather it is movement between the bewildering multiplicity of an infinity of timelines. Thus, you can kill your grandparents without effecting yourself, since “they” are grandparents to another person occupying another timeline. Killing them causes “his” extinction, but not yours. Get it? If this stuff is true, then where are the “visitors”? Why are we not seeing people, or beings, or things from the far future? Do the math. Our timeline is one of a virtual infinity of timelines. What are the odds of these visitors from the far future choosing the line we happen to occupy? Do the math again, and assume that these visitors actually will visit us. The question is when? Since they appear not to have visited us before this moment, we can expect them to arrive at any future moment – of which a great deal lie ahead of us. Even a very short-term examination of this problem gets one deeply enmeshed in a swirling infinity of timelines and possibilities. Working through this problem redefines the concept of a Herculean task. It also highlights the value of living a day at a time, since time waits for no man …although it does meander, swirl around, and even circle back on itself, and it splits faster than a crazy woodcutter. |