Physics and the search for the Holy Grails

Written by Sharad Raghavan | Updated: Apr 22 2011, 07:56am hrs
The world of physics has several holy grails: unifying the incompatible theories of quantum physics and general relativity, finding proof for the existence of the Higgs boson (the god particle) and explaining the universes accelerating expansion. There are more, but they tie into these three in one way or another. A remarkable new theory proposed by University at Buffalo physicist Dejan Stojkovic and colleagues has the potential to bring at least two of these three grails within grasp.

The theory suggests that the early universe, which exploded out of a single, tiny point, was actually one-dimensional, like a straight line, before expanding into two dimensions, and then later the three dimensions we see today. Basically, it says that as the universe grows, it keeps acquiring dimensions, which implies that a fourth dimension in space might be possible. In fact, Stojkovic says that a fourth dimension may already exist at a massive, cosmological scale.

If true, this theory lays to rest all kinds of dilemmas and puzzles plaguing physicists. If the universe at tiny levels (the realm of quantum physics) has fewer dimensions, mathematical discrepancies between quantum theory and general relativity (dealing with massive objects) will disappear. This is important because while both these systems explain more or less everything in their respective domains, they completely fall apart when taken into the others realm. For example, if you used quantum theory to predict the movement and behaviour of planets, stars and solar systems, you wouldnt get a meaningful answer as hard as you try. The same holds for using general relativity at the tiny levels of quarks, gluon and bosons (the elusive and restless population of the quantum world). The prospect of finding a theory that unifies these two has physicists almost quivering with excitement.

Also, the fact that dimensions get added to the universe as it grows, if true, could explain its accelerating expansion. This is doubly exciting because it could provide a viable alternative to dark matter, which most physicists believe exists, but cannot find. The existence of dark matter and its properties is what scientists are using to explain the universes expansion at the moment.

This is all very well, and stands to turn the physics world upside down, but can it be proved In a new paper in Physical Review Letters, Stojkovic and Loyola Marymount University physicist Jonas Mureika have come up with a test that could prove or disprove their theory of vanishing dimensions. Basically, because even light takes time to reach Earth from the far reaches of space, telescopes peering far, far away are in essence looking back into time. Now, gravitational waves cant exist in one- or two-dimensional space, so the reasoning is that the Laser Interferometer Space Antenna (LISA), a planned international gravitational observatory, should not detect any gravitational waves from the early universe.

It seems LISAs got the key to the grails, its only a matter of time before she hands them over.