Thinking about jokes -- what makes something REALLY funny?

A few years ago I was at a conference with a bunch of engineers and scientists (yeah, a really funny bunch) and the guy at the podium told a joke that, in hindsight, has to have one of the funniest things I (and I guess, a couple of other people in the crowd) ever heard. The joke goes like this:


Werner Heisenberg, Erwin Schrodinger and Wolfgang Pauli are on their way to a conference. Heisenberg is driving and gets pulled over by a cop.

Cop: "Do you know how fast you were driving?"
Heisenberg: "No, but I know exactly where I am."
Cop: "You were going 123 kilometers per hour."
Heisenberg; "Great! Now I'm lost!"

The cop finds this conversation unusual and demands to search the vehicle. After looking in the trunk, he returns to the window.

Cop: "Do you know you have a dead cat in your trunk?"
Schrodinger (angrily): "Well, I do now."


So that was the end of the joke. There was a little polite laughter. Then silence. About three full seconds later, a couple of other people and I suddenly got the joke and absolutely snorted.

So, my question is: Do you find this funny, and if so, why? You need to know at least a little physics or it might not make much sense so my apologies for wasting the time of anyone who just doesn't get it. But if you REALLY get it... let me know.