In this article Joe Butterworth (of the University College London's High Energy Physics Group) writes an excellent example of what science journalism should be.

In this article Joe Butterworth (of the University College London's High Energy Physics Group) writes an excellent example of what science journalism should be. I think he does a very good job in explaining the distinction between inelastic and elastic photon-photon scattering. (Unfortunately he also refers to photon-proton work he's done in the past, so maybe he's right to revert to light-light scattering later in the article, and perhaps should have done that almost from the beginning as an aid for the casual reader.) (A précis might be: when looking at a point fixed in space relative to you, a pair of high-momentum photons with well-defined trajectories through that point can interact at or very close to that point with the result that the two photons will have new trajectories but unchanged momenta.)