Shaking up Dark Energy?

For twenty five years the issue "Dark Energy' has been a bug-a-boo at least in the discipline of cosmology.

Earlier it was widely believed after the detection of Dark Energy at 1998 that it was a constant nature. Measurements by some of the best scientists could not find any substantial variation. Not all scientists bought into that. Variations were attempted to be pointed out shortly after. However having it explained as a constant became a concensus.

Papers and conjectures flew back and forth. One view on having Dark Energy not as a constant was entertained by various scientists with variety of purports. They would not give up.

More recent to present time there have been papers that hinted more and more that Dark Energy was not constant over time, at least in the past. This also proved to be a challenge to the Standard Cosmology model's stability.

Special studies were done by Dark Energy Survey, Dark Energy Spectroscopy Instrument, DESI, Dark Energy Cam and combined with other studies. A collaborated paper with 40 scientists was put out, by DES, Fermilab Pub from the March meeting of the American Physical Society's Global Physics Summit , after observation of 15 million celestial objects and analysis indicate that Dark Energy is not fixed nor constant.

One of the findings is that the current, lambda standard model is disfavored by

4.2 sigma. A highly important quote to challenge the current standard model as noted by Enrique Paillas, U. of ArizonA. This includes computation on the BAO.

Alexie Leauthaud observes we tend to fix the energy density value at -1. The data of the study indicates there is fluctuation. That 11 billion years ago the energy density was recorded at -1.4. It is noted that has changed to -0.7 currently. That any reading  of value below -1 is cause for rewrites if sustained. More studies from space craft will be needed to help ascertain that.

A further result indicates the cosmic acceleration began about 7 million years ago and reached its peak about 2 billion years ago and may show signs of slowing. But the Dark Energy of today is still accelerating and pushing matter apart and will do so for some time.