Arp's beliefs about cosmic light were eccentric, and probably wrong. But his career is a reminder that most breakthroughs are made by those who follow their muse regardless of what conventional wisdom says. Einstein initially was seen as an eccentric, his views clashing with received wisdom of his period. Many notions today confidently asserted in the science departments of major universities are sure to be discredited someday. Researchers like Arp, who refuse to go with the flow, are essential to progress.
Though Arp's specific contentions do not appear to stand much chance of being proven, his general point -- refusal to endorse Big Bang theory -- may someday be a winner.
There is considerable evidentiary support for the Big Bang -- the movement of galaxies, the existence of cosmic background radiation (space appears once to have been heated by something far more powerful than all the stars combined) and the composition of the oldest stars all support Big Bang thinking. But the cosmology and astronomy communities tend to treat the Big Bang theory as already proven when there are many question marks, and not just that the prior condition is unexplained. If space itself expanded in the initial instant of the Big Bang at millions of multiples of the speed of light, um, how could that be? Why did whatever triggered the Big Bang never happen again? Why did physical laws and natural constants turn out to have exactly the values that make the universe stable, when other laws and values seem at least as likely? The theory holds that most of the material released by the Big Bang immediately annihilated in matter-antimatter reactions, meaning there was not only enough material for an entire universe in a point with no dimensions but enough material for thousands of universes. Maybe, but that's really hard to believe.
As recently as a decade ago, astronomers and cosmologists wanted to know whether distant galaxies were moving at a steady speed or were slowing down, as momentum of the Big Bang wore off. It turned out they are speeding up. That could happen only if some form of energy were acting on the galaxies to accelerate them. Researchers decided that dark energy -- which cannot be detected or explained -- exists and comprises around three-quarters of universe, which is the number needed to explain the observed acceleration. The science world has been rather cavalier about saying, "We just noticed three-quarters of the universe cannot be seen or explained in any way. Next question?"
Perhaps there are good answers to mysteries of the Big Bang and dark energy, but answers are yet to be found. The work of physicists and cosmologists, and writing about their work, is full of assertions that humanity already knows information spanning eons in time and the breadth of the firmament. Check this unintentionally hilarious news release, which asserted Johns Hopkins University professors are certain they know what happened in the first trillionth of a second of the Big Bang, as "ripples in the very fabric of space may have been created." What are "ripples in the very fabric of space?" Star Trek writers couldn't explain that phrase, and neither can anyone at NASA. But we're certain we know exactly what happened 13.7 billion years ago.