29 September 2005
3 And 7 Lucky Numbers For Dimensional Evolution
by Kate Melville
Researchers from the University of Washington and Harvard University have turned up some interesting findings about possible realities based on math modeling the beginnings of the Universe. Andreas Karch (UW) and Lisa Randall from Harvard set out to model how the Universe was arranged right after the big bang, and then watch how the cosmos evolved as it expanded and diluted. The only assumptions they made were that it started with a generally smooth configuration, with numerous structures - called "branes" (membranes) - that existed in various spatial dimensions from one to nine.
The researchers found that as the cosmos evolved and the branes diluted, the branes that survived displayed three dimensions or seven dimensions. They believe the way our universe started and then diluted as it expanded - called the relaxation principle - favored formation of three- and seven-dimensional realities. "That's what comes out when you do the math," said Karch, author of the paper that appears in Physical Review Letters. "Other realities, either three- or seven-dimensional, could be hidden from our perception in the Universe. There are regions that feel 3D. There are regions that feel 5D. There are regions that feel 9D. These extra dimensions are infinitely large. We just happen to be in a place that feels 3D to us," he added.
In our reality, forces such as electromagnetism only operate in three dimensions and behave according to our laws of physics, their strength diminishing with distance. But Karch and Randall say that gravity cuts across all dimensions, even those not recognized in our reality. They further theorize that the force of gravity is localized and, with seven branes, gravity would diminish far more quickly with distance than it does in our three-dimensional world.
Gravity altered in such a way would generate a very odd reality. "With gravity diminishing rapidly with distance, a seven-dimensional existence would not have planets with stable orbits around their sun," Karch said. "I am not precisely sure what a Universe with such a short-range gravity would look like, mostly because it is always difficult to imagine how life would develop under completely different circumstances. But in any case, planetary systems as we know them wouldn't form. The possibility of stable orbits is what makes the three-dimensional world more interesting."
Source: University of Washington