In 1998 a force called Dark Energy was discovered when the Hubble Space Telescope (HST) found that, a long time ago, the Universe was actually expanding more slowly than it is today. In other words its expansion has not been slowing due to gravity, as everyone thought, it has been accelerating.
Since then several different explanations have been proposed. Maybe it was a result of a discarded version of Einstein’s theory of gravity, one that contained what was called a “cosmological constant.” Maybe there was some strange kind of energy-fluid that filled space. Maybe there is something wrong with Einstein’s theory of gravity and a new theory could include some kind of field that creates this cosmic acceleration.
However most cosmologists would agree the best way to understand why dark energy is causing universe’s expansion to accelerate would be to observe how it interacts with its environment and then try to incorporate it into a theoretical model.
For example we know form observations that it is not causing three-dimensional space to expand towards a time but a spatial dimension.
Unfortunately Einstein theories only contain three spatial dimension and one time dimension.
Therefore, to explain the observed spatial expansion of the universe one would have to assume the existence of a another *spatial* or fourth *spatial* dimension in addition to the three spatial and one time dimension that Einstein’s theories contain to account for that observation.
This would be true if Einstein had not given us a means of converting the geometric properties of his space-time universe to one consisting of only four *spatial* dimensions.
Einstein defined the geometric properties of a space-time in terms of a dynamic balance between mass and energy defined by the equation E=mc^2. However when he used the constant velocity of light in that equation to define that balance he provided a method of converting a unit of time in a space-time environment with unit of space in four *spatial* dimensions. Additionally because the velocity of light is constant he also defined a one to one quantitative correspondence between his space-time universe and one made up of four *spatial* dimensions.
In other words by defining the geometric properties of a space-time universe in terms of mass/energy and the constant velocity of light he provided a qualitative and quantitative means of redefining his space-time universe in terms of the geometry of four *spatial* dimensions.
The fact that the equation E=mc^2 allows us to quantitatively derive the spatial properties of energy in a space-time universe in terms of four *spatial* dimensions is one the bases of assuming as was done in the article “Defining energy†Nov 27, 2007 that all forms of energy 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.
In other words one can use Einstein’s equations to quantitatively define energy in terms of a spatial displacement in a “surface” of a three-dimensional space manifold with respect to a fourth *spatial* dimensions instead of one in a space-time environment.
We know from the study of thermodynamics that energy flows from areas of high to ones with low density very similar to how water flows form an elevated or “high density” point to a lower one.
For example if the walls of an above ground pool filled with water collapse the elevated two-dimensional surface of the water will flow or expand and accelerate outward towards the three-dimensional environment sounding it.
Yet we know from observations of the cosmic background radiation that presently our three-dimensional universe has an average energy component equal to about 3.7 degrees Kelvin.
However this means that according to concepts developed in the article “Defining energy” (mentioned earlier) the three-dimensional “surface” of our universe which has an average energy component of 3.7 degree Kelvin would be elevated with respect to a fourth *spatial* dimension.
Yet this means similar to the two dimensional surface of the water in the pool three-dimensional space will accelerate and flow or expand outward in the four dimensional environment surround it.
This shows that one can explain how and why the force called Dark Energy is causing the accelerated expansion of the universe in terms Einstein’s theory of gravity by converting or transposing his space-time geometry to its equivalent in four *spatial* dimensions.
Later Jeff
Copyright Jeffrey O’Callaghan 2013