Avignon Day 2: Cosmological Neutrinos

By this point in my life, when I attend a large-ish conference like this one the chances are good that I'm older than the average participant. Certainly true here. It's a great chance to hear energetic young people tackling the hard problems, and I certainly have the feeling that the field is in very good hands. It's also a good reminder that we old people need to resist the temptation to fall into a rut, churning out tiny variations on the research we've been doing for years now. It's easy to get left behind! Still, it's also nice to hear a talk on a perennial topic, especially when you hear something you didn't know. Yvonne Wong gave a very nice talk on "hot relics" -- particles that were moving close to the speed of light in the early universe. (They may have slowed down by now, or maybe not.) Neutrinos, ...