I am doing a new semester project this semester on primordial black holes with Jerry Ostriker, one of the most senior figures in astrophysics. I was discussing some physics of the early universe with Jerry, and we tried to look up some stuff in a cosmology textbook written by Jim Peebles, another senior statesman in astrophysics who works across the road in the Physics Department here in Princeton.

We couldn't seem to find what we were looking for, and then suddenly Jerry picks up his phone and calls up Peebles. I was speechless as Jerry started quizzing Peebles on some subtleties of hydrodynamics in the early universe.

After several minutes of conversation on the phone, Jerry turns to me and dead-pans: 'Well, we didn't get very far'.