RRB: “My calculations are irrelevant on this point. They are only valid in speaking of the shock reflection.”
Ogle: “How fast did it go?”
RRB: “Those numbers are meaningless. I have only a vacuum above the cap. No air, no gravity, no real material strengths in the iron cap. Effectively the cap is just loose, traveling through meaningless space.”
Ogle: And how fast is it going?"
This last question was more of a shout. Bill liked to have a direct answer to each one of his questions.
RRB: “Six times the escape velocity from the earth.”
Nope, it would just have bursted due to thermal schock and pressure. Escape velocity, what are you dreaming, is the lid made of tungsten?
This is the origin apparently.