Doubts in the Dark
The Cosmic Microwave Background. Who can see the cosmic acceleration? It's a matter of interpreting the data, and who gets the data first.
When redshifts of Type Ia supernovae were found to increase non-linearly, it was hailed as evidence that the Universe was accelerating. This would violate most laws of gravity, not to mention the First Law of Thermodynamics on energy conservation. To explain the "accelerating" data, scientists claimed a repulsive "dark energy." The first reports from the Wilkinson Microwave Anisotropy Probe were interpreted to favour DE, though WMAP says nothing about acceleration.
To quote Roger Penrose: "In my opinion, we must be exceedingly cautious about claims of this kind--even if seemingly supported by high-quality experimental results. These are frequently analysed from the perspective of some fashionable theory."
Doubts about the "standard" cosmology and its dark epicycles continue to spread. From Space.com:
Dark Energy and Dark Matter Might Not Exist, Scientists Allege
"Ever since these concepts were first proposed, some astronomers have worked feverishly to figure out what each thing is, while other astronomers have tried to prove they don't exist, in hopes of restoring the universe to the more understandable place many would like it to be.
"A new look at the data from one of the telescopes used to establish the existence of this strange stuff is causing some scientists to question whether they really exist at all. Yet other experts are holding firm to the idea that, whether we like it or not, the 'dark side' of the universe is here to stay."
The article cites work by astrophysicist Tom Shanks of Durham University. His colleague's studies show that "dark energy" is a matter of interpretating data. The first WMAP data release was massaged to favor DE, even thjough other interpretations are possible. Experts who have bet their careers on DE will peddle it until their last breath. In the meantime, the spotlight will move elsewhere. Evidence for a changing speed of light grows.