Let’s talk about light. We understand light like that from the sun to be carried by small, invisible particles called photons. Photons have no mass – at least when they’re at rest, but photons are always moving and they therefore possess a non-zero momentum.
When something with momentum collides with something else, that momentum is transferred in the form of a pressure on the surface of the object. Does light exert a pressure? I talked to Professor Ulf Leonhardt from the Weizmann Institute of Science in Israel who has helped publish a paper that has a somewhat controversial result on the subject.
Listen to it on Soundcloud here.