ThursdayThoughts for this week examines the causes of acceleration of the redshift. Many consider these causes to be synonymous with the term "Dark Energy". Note that Dark Energy and Dark Matter are not the same thing.
Acceleration of the redshift conflicts with traditional views inherent in the Big Bang model. To overcome this conflict the concept of Dark Energy was introduced. Many believe that Dark Energy and Einstein's Cosmological Constant, Lambda, are the same.
Nature's Universe (see thought 32) requires both redshift and an acceleration of redshift in the more central portion of the universe. It also requires a lessening of redshift in the farthermost reaches of the universe.
The causes of accelerated redshift in Nature's Universe are:
The measurement of accelerated redshift includes all three causes of acceleration. This would fall under the umbrella of Dark Energy. In theory, Einstein's Cosmological Constant would be the first cause, 'energy' of empty space. Likely, the acceleration due to all causes is indiscriminately lumped together and considered to be from the first cause when determining the Cosmological Constant.
Cause 1, the 'energy' of empty space, supports Einstein's Cosmological Constant. On a far deeper level, it conflicts with general relativity due to the continuous slowing of time everywhere in Nature's Universe. (see Thought 18) Space provides the embedded mechanism of time that acts as a flywheel which drives gravity. This is perceived as the 'energy' of empty space. It could also be considered a gravity sink.
Cause 2, the increasing mass near the boundary of the universe, directly accelerates matter that is more centrally located in the universe. Nature's Universe departs completely from the Big Bang model in this respect. New matter is added to Nature's Universe as the boundary expands outward. The new matter results from sorting out connections to form a fabric of space. This new highly energetic matter is also responsible for the Cosmic Microwave Background.
Cause 3, the slowing universe effect, becomes noticeable in weak gravitational fields at great distances from a large mass. The gravitational field was generated in a faster universe, but it is propagating through a slower universe at large distances. This is not a recognized effect, but MOND gravity supports this view. The distances likely need to exceed one million light-years.
Cause 3 contributes to redshift because the inner portion of the universe would contain a lower density of matter. That redshift would work in the same way as the immediate time dilation effect of local masses. Why does it contribute to the acceleration of redshift?
Cause 3 is tricky to understand. A person might think that the effect of moving from a faster universe to a later slower universe would create a blueshift. This does not affect the redshift because the universe is slowing both behind and ahead of the moving photon.
Cause 3 creates a redshift because at any instant time is faster in the inner universe than it is in the outer universe due to the delayed effect of the mass density. It is the gradient of this instantaneous relationship that causes redshift. The redshift accelerates because this gradient increases as Nature's Universe evolves. This acceleration is what contributes to Dark Energy.
I do not know the magnitude of Cause 3 compared to other Causes. My guess, and it is a guess, is that Cause 3 is a substantial cause for redshift over the distance from the outer universe to the inner universe. The acceleration of this redshift gets included as one of the Causes for Dark Matter.