ATLAS sees first direct evidence of light-by-light scattering at high energy
There's an interesting implication here for redshift observations and Hubble expansion, insofar as it provides a mechanism for photons to lose energy while in a highly sparse medium, populated largely only by other photons.I'm keeping my money on expansion and dark matter being hooey brought about by incomplete of incorrect understanding of light.Only recently there was that rather interesting piece about simulated momentum transfer from photons in media.It's exciting - we'll potentially be lopping off a huge branch of dead wood from the tree of science, from which new ideas can grow.