What is dark energy?
Dark energy is essentially a filler concept invented for the sole purpose of explaining observations that, within the context of the Big Bang Cosmology, are interpreted as an accelerating expansion of the universe. The notion exists and was invented for the sole purpose of making the Big Bang cosmology fit observations.
The Big Bang cosmology naturally tended to predict one of two fates for the universe. The first was that it would continue to expand, getting slower and slower, but never actually stopping. If it were more massive than a critical point, the expansion would come to a stop, and the universe would start to collapse. The hope of this one was that it would result in a new Big Bang, eliminating the idea of a beginning.
When the measurements were actually made using type 1A supernova, neither prediction turned out to be true. This is because, as interpreted within the context of the Big Bang, the expansion rate of the universe was accelerating. In other words, the Big Bang cosmology offered two of three possibilities and still missed the prediction. To fix this problem, a patch was invented. There was a modification to Einstein's field equations, called dark energy, that exists only to eliminate a failed prediction of the Big Bang Cosmology.
The Gravitational Well Resulting from This Cosmology.
The Big Bang Cosmology is based on what is called an unbounded universe. In other words, there is no edge to the universe beyond which there is no matter. This results in a universe that is either infinite or bends back on itself in a spherical context. There was no evidence for this, other than the fact that the only other alternative is that the earth is near the center of the universe, a concept which is repugnant to atheists.
If, however, you place the Earth near the center of a bounded universe, where there is an edge beyond which there is no matter, then there would be a net gravitational well with the Solar System at the bottom. Space itself would be essentially flat with gravitational acceleration at normal levels. There would still be a degree of time dilation, depending upon the size of the universe and the amount of mass around the edge.
The Blue Shift from the Gravitational Well.
This gravitational redshift would produce a blue shift in distant galaxies from our perspective. Now with the expansion of the universe and shallowing out of the gravitational well, this blue shift would be relatively small compared to the red shift, but it is enough to affect observations.
The key to understanding this is the fact that as you get deeper into a gravitational well, time slows down for you relative to other parts of the universe. One of the consequences of this is that those parts of the universe seem to be moving fast, making the light from them bluer from your perspective.
The Blue Shift in Type 1A Supernova Data.
The major consequence of this is that the type 1A supernova data, which is the basis for the conclusion of an accelerating expansion, would be slightly blue-shifted. This blue shift effect would increase as you got further out, resulting in an apparent increase in the expansion rate of the universe over time.
However, it needs to be understood that this is a natural prediction of a bounded universe, but totally unexpected in a bounded universe such as the Big Bang. Consequently, this blue shift eliminates the idea of an accelerating expansion and works with either a constant expansion or a slowing expansion.
Eliminates the need for dark energy.
The ultimate consequence of this is that it eliminates any need for dark energy. This is because the only basis for the idea of dark energy itself is eliminated. The data is simply explained by the Earth being at the center of a gravitational well caused by the universe having an edge.
Conclusion
The simple fact of the matter is that dark energy was invented purely as an effort to save the Big Bang from observations contrary to its natural predictions. The problem is that it eliminates any general gravitational effects by insisting on an unbounded universe. If, however, there is a sufficiently massive edge to the matter of our universe, then the Earth is in a gravitational well that produces a blue shift effect, which has been interpreted as an accelerating expansion. This eliminates any need for so-called dark energy.
