Attempts to explain dark energy persist. At https://phys.org/print404102809.html … 'violations of energy convection in the early universe may explain dark energy' we are told. You might struggle with the use of the word violation but it is in keeping with modern changes in meaning heaped upon us by clever people using smoke and mirrors to cloud what they really mean. In this instance, there is a problem with Big Bang and the idea is to both provide an explanation but create obfuscation so that a casual reader may not see all the trees in the forest. It is also a sort of butch re-meaning of a word, a sort of back somersault. The paper is in 'Physical Review Letters' January 2017 and concerns the problem of the uniformity in the expansion of the universe following Big Bang. It is presented as a fresh look at the problem of the 'cosmological constant' which is now thought to define dark energy.
At https://phys.org/print404120616.html … ancient tree rings suggest sun spot cycles have been ongoing for 290 million years (at least). An article in Geology journal (2017) by Ludwig Luthalt and R Rossler 'Fossil forest reveals sun spot activity in the Permian'. Over at https://tallbloke.wordpress.com/2017/01/20/ancient-tree-rings-suggest-su…. … where the issue is discussed more deeply. The study involves 43 petrified trees (slices of trunks) and they were able to count the rings (under a microscope). The trees all died at the same time and the tree rings cover a period of 79 years prior to their death. The solar cycle (if that is what it is) was just 10.6 years in comparison with 11.2 years in the modern world. Therefore the length of the solar cycle differed – albeit slightly. The researchers go on to claim that this means the sun has been constant for 200 million years (and probably much longer).
The comments are quite interesting. One mentions magnetised plasma affecting the cycle and another says the cycle proves how important the sun and moon are for life on earth. Somebody brings in the subject of Ice Ages in order to claim the sun has not been constant, while still another suggests the trees might not really be as old as claimed (but how old is not stated). Another associates the sun's activity to an expansion and subtraction of the orbits of the planets (which is an interesting idea). Another bring sup the Swedish tree ring research programme at www.cybis.se/forfun/dendro/hollstein/belfast/index.php while another came up with a different explanation for black holes – as gravitational eddies, whirlpools in a deep calm pond.