We may soon know because the scientists at CERN have been given the go-ahead to perform an experiment that will determine if it does. As describe in the NewScientist article “Antimatter mysteries 3: Does antimatter fall up?” Apr 29, 2009, the AEGIS team will use uncharged particles to prevent electromagnetic forces from drowning out gravitational effects. It will first build highly unstable pairings of electrons and positrons, known as positronium, then excite them with lasers to prevent them annihilating too quickly. Clouds of antiprotons will rip these pairs apart, stealing their positrons to create neutral antihydrogen atoms.
Pulses of these anti-atoms shot horizontally through two grids of slits will create a fine pattern of impact and shadow on a detector screen. By measuring how the position of this pattern is displaced, the strength – and direction – of the gravitational force on antimatter can be measured.
If it is found that it does in fall up them we will be required to rethink our understanding of the geometric structure of our universe because Einstein’s Theory of General Relativity tells that objects that create gravitational field cause time to “move” slower. However due to the symmetry of his equations one could also say that the time slowing results in the formation of a gravitational field. Therefore one must assume that a gravitational field must always be attractive because observations indicate that time only moves in one direction forward.
However the fact that one can use Einstein’s equations to qualitatively and quantitatively redefine the energy he associated with gravity in terms of four *spatial* dimensions is one bases for assuming as was done in the article “Defining energy?†Nov 27, 2007 that it can be derived in terms of a spatial displacement in a “surface” of a three-dimensional space manifold with respect to a fourth *spatial* dimension as well as one in a space-time dimension.
However unlike time which is observed to only move in one direction forward observations tell us that we can move in spatially in two directions up down backwards and forwards.
Therefore if the universe was made up of four *spatial* dimensions there should exist a form of mass that possess a negative gravitational potential.
One candidate for such a mass is antimatter. We know from observations that in it has an opposite electrical charge than its matter counterpart. Therefore it is logical to assume that it posses a gravitational field that is oppositely directed from that of matter.
In other words if it is found that antimatter falls up or possess negative gravitational potential then it is more probable that our universe is physically composed of four *spatial* dimensions because it is easier to explain how a universe made up that can support a negative gravitational potential while it is as was mentioned earlier much more difficult in one made up of four dimensional space-time.
Yet if found to be true it does not mean that Einstein’s theories are invalid because his theories and predictions were based on pure mathematics and as mentioned earlier a universe consisting of four dimensional space-time and four spatial dimensional are mathematically are equivalent in every respect.
Therefore, if the scientists at CERN find that anti-matter particles fall up they would be required to not only rethink the relationship between matter and antimatter but also completely revamp our understanding of the mechanism responsible for gravitational forces and consider the possibility that space is composed of four *spatial* dimensions instead of four dimensional space-time.
Later Jeff
Copyright Jeffrey O’Callaghan 2009