The facts:
No antigravity has been observed ... and no DE has been observed also.
It was discovered (measured) in 1998 an acceleration in the expansion of space.
The mass (M) is the source of gravity (G).
Every force has a source of it, charges, masses,... .
The source of antigravity (AG) is ??????????? (SoAG).
In the absence of apparent source of AG we can assume that antigravity was imprinted in space long time ago and the sources disappeared. It is as the SoAG were converted in AG preserving the energy balance.
In this way, and it is all I can conceive, the AG is a field, and it is the gradient of field that produces a force.
In a expanding space it is expectable that any gradient will have to decay, the same as with the decrease of photon energy, by the reddening of light, as time goes by.
But it is the contrary effect that is needed: to motivate an accelerated expansion the gradient must grow. How can it be growing ? Can we imagine any probable cause? We have the same problem with the space expansion: no probable cause.
To name the source of the effect as DE or AG is not important because none offer a solution. They are just names of the probable causes of the symptoms (the measures we have).
There are sources of gravity so distant of us that the associated gravity field is reaching Earth only now. In physics it is strongly beleived that gravity propagates away of sources at c speed. Following Einstein we have no reason to doubt.
I've no way of convincing myself that the distant stars have the same energetic content now, billions of years past the moment they released the gravitational field, that only now we sense. If here and now the sorrounding energy content is different than here in the past then I will have to assume that the source of this change (the distant stars) have to change also as time go by.
If it is not so then the SoAG can not have disappeared.
Busted by the mesuring process ?
I am saying that stars in the past had more massive atoms than the ones we see around and the mass is beeing converted in gravitational/electrostatic fields as field spread away. I know that it is hard to beleive, but can you think that the universe is still viable if all atoms have the double of the mass thay show now? Of course that they have to be also twice as large. And, if c is constant, the time unit is also twice as large. The light emmited in the past by those larger atoms have longer wavelengths (red) compared to the light emmited in the same process.
We measure the world with atoms, i.e. properties derived from them and this fact make impossible an independent measure in the lab, because we measure ratios and those are kept constant.
The measured space expansion is an artifact of the fact that the 'rule' we use is shrinking: for the same physical distance we have now the double of the measure if the atoms shrinked to half.
The law that relates the evolution of the source is naturally exponential (think of radioactivity) and that gives us the illusion of an accelerated expansion.
With this model A self-similar model of the Universe unveils the nature of dark energy (pdf), there are no free lunches at all, no DE, no inflation era, no space expansion, no... new particle, no new force, no new field.
With my modest contribution a new model is presented formally, with all equations you like, with all physical reasonings you deserve, and compared with the official $\Lambda CDM$. I still have expectations that sometime, someone will present argumentation ($*$) and I will be around to discuss the subject.
($*$) as usual downvotes are expected but, in the absence of any argument, I can consider it an implicit acceptance of impotence.
At least I expect that the author of the question will understand why I'm frontally against any kind of AG/DE, and I hope he/she keeps the motivation in the search of the hidden reality.
PS:
GR is a gravitational theory only (mass/field problem). In a spherical symmetry the distance between two points have two solutions: the short one and the other one (ex: I can go directly from London to Casablanca or using the same meridian go from London to North pole, then thru the equator, next South pole and finally Casablanca). Einstein formulated GR thinking that the matter was ageless and, as part of the solution he incorporated the $\Lambda$ to account for the longer path. I've several problems with the appropriation of GR to other purposes that gravitation because: The more we measure the space at large the more 'flat' it is. It his accepted the matter had a beginning and the GR model was consistent with an ageless universe. After 1998 $\Lambda$ was refurbished to explain DE, without explaining a single bit. The last reason is that data agrees with the model of shrinking matter without need of $\Lambda$ (It has only one parameter $H_0$) and BBT has six (?) and by WP "and have made the unexpected discovery that the expansion of the Universe appears to be accelerating." and I read "unexpected discovery" == "wrong model".
John Cramer, the source of one of the cited articles above, tells me:
"Dear Brad,
Carver Mead says that G4v is not disproved, but calculations are needed to see if it can do as well as GR in fitting the aLIGO data. The problem is that the main differences between G4v and GR predictions are in the polarization behavior, and Hanford and Livingston, because their arms are almost parallel, are relatively insensitive to polarization. A LIGO colloquium speaker at UW last week said that they may have to wait until VIRGO in Italy comes on line (real soon now, but they need to see an event after it does) to have the polarization sensitivity to falsify one of the predictions.
Regards,
John Cramer"
So, indeed, it seems the parallel nature of the LIGO arms is making it difficult to make a determination. VIRGO was mentioned, but I also do wonder if eLISA will provide any insights on this question:
https://www.elisascience.org/
Best Answer
Carver Mead's version of the G4V theory includes a 2nd order term in the equation for inertial momentum which is proportional to the integral of the velocity of all relativistic energy in the universe divided by its distance from the body of interest. The term is expressed as being proportional to the inertial vector potential. It provides a description of a mechanism which, if found to exist, would embody Mach's principle. Because of its sign, it would also tend to explain the currently unexplained expansion observed in macroscopic regions of the universe which is currently ascribed to "dark energy." It contains no "fudge factor" analogous to the intermittently-hypothesized cosmological constant. The LIGO experiment should imminently provide data of sufficient accuracy to differentiate between G4V and GR, which is cause for excitement. For an initial foothold, see: https://youtu.be/XdiG6ZPib3c