The theory of everything.
A question posed by the Science and Technology editors of The Economist was “…does the universe have to be the way it is?” and this is an important question because if it were only slightly different, life as we know it, could not have occurred. In physics, this is known as the Anthropic Principle and it bothers a great many physicists. They can’t understand, for instance, why space has to have only three dimensions. Apparently, there isn’t a physical or mathematical rule that stops dimensions at three.
The article I was reading goes on to explain that Andreas Karch and Lisa Randall have come up with a reason why physics are biased towards three dimensions. At the same time, their studies show a similar bias towards 7 dimensions!
OK, so where are those other 4 dimensions? Some believe that they are rolled up so tightly, that they can’t be seen; such as in Calabi-Yau shapes. Another group believes that they aren’t rolled up at all, but we can’t see them because we aren’t free to move about in them. We live in a three dimensional world or surface, embedded within a higher dimensional landscape. This surface, or membrane is the one that Karch and Randall have studied (mathematically) and they believe that there are equal parts of membranes and anti-membranes in the universe; just as there is matter and anti-matter.
Since the universe would be filled with equal numbers of membranes and anti-membranes, 3 dimensioned membranes and 7 dimensioned membranes would soon dominate since they would be least likely to run into their opposite numbers and be destroyed. So they theorize that there is a mathematical possibility of a seven dimension world! Very cool…
Or it isn't nearly as spookey and dramatic if there IS... "a physical or mathematical rule that stops dimensions at three".
ReplyDeleteThe extremely small positive value of the cosmological constant means the big bang actually resulted in a near perfect balance between runaway expansion and gravitational recollapse, which actually puts the universe about as far away from the tendency toward heat death as you can possibly get, and yet still be heading in that direction. The principle of least action says that it is no coincidence that this near-perfectly symmetrical configuration is also the most energy-efficient means for dissipating energy, because this means that tendency toward "heat-death" is most economically restricted to the most-even distribution of energy possible.
The universe actually expresses a grand scale natural preference toward the most economical form of energy dissipation, so if the second law of thermodynamics is telling us that the entropy of our expanding universe increases with every action, then the anthropic principle is telling us that this will occur by the most energy efficient means possible, since the flatness of the universe is one of the many coincidentally ecobalanced requirements of the principle.
If the second law of thermodynamics points the arrow of time, then the anthropic principle determines that time is maximized.