First it was dark matter,1 then came dark energy,2 followed by dark fluid,3 dark flow,4 and dark radiation5; and now a new entity is suggested for the dark sector of particle physics—dark photons. The dark sector is full of hypothetical entities designed to save the big bang story but it is really just a lot of cosmic storytelling.6
Previously I have argued that dark matter is a sort of ‘god of the gaps’, the ‘unknown god’,7 in astrophysics. It is an unknown invoked to explain the inexplicable,8 which, if you follow the chain of logic, is required to maintain a belief in the big bang paradigm. Its existence is only inferred from the application of known physics to certain observations in the universe.9 Without assuming the existence of some exotic unknown dark matter comprising about 25% of the matter/energy content of the universe10 the standard big bang model would have to be discarded as a total failure.
Dark matter has never been observed in space or in any laboratory experiment.
Now a new observation of four colliding galaxies in the Abell 3827 cluster apparently may shed new light on the conundrum.11 See the four galaxies in the centre of the figure here.