Werner Heisenberg is pulled over by a police officer. After checking his license and registration, the cop asks “Do you have any idea how fast you were going?”
“Not at all,” replies Heisenberg, “but I know precisely where I am.”
The cop says “I clocked you doing eighty miles an hour.”
“Oh great!” says Heisenberg. “Now I’m lost!”
Werner Heisenberg was a central figure in the development of quantum mechanics, the branch of physics that deals with the strange comings and goings of the subatomic realm. His name is connected most frequently with the Uncertainty Principle; more about that in a moment.
There’s a lot of history behind the development of the modern atomic theory and quantum mechanics, not all of which is relevant to this joke. Still, I would be remiss not to include some links so you can refresh your knowledge about how scientists know what they know about impossibly tiny subatomic particles.
- First, spend four minutes with this video to get acquainted with the origins of quantum mechanics.
- atomictimeline.net has an incomplete “Who’s Whom?” of atomic philosophers and physicists spanning from ancient Greece to modern times.
- David Harrison of the University of Toronto provides a brief but somewhat academic narrative of the birth of quantum mechanics through the work of Heisenberg and Erwin Schrödinger, with a smattering of Eastern philosophy thrown in for good measure.
- Todd provides a decent introduction to some principles of quantum mechanics.
- And finally, if you don’t feel like reading the rest of this article (or even if you do!) spend four more minutes with this video that brilliantly demonstrates the Uncertainty Principle in a simple experiment.
In the first decades of the 20th century, physicists were making enormous strides toward understanding how protons, neutrons, and electrons work together to make atoms. It was becoming apparent, however, that subatomic particles still had a few closely-guarded secrets. Werner Heisenberg, a German theoretical physicist and the star of today’s joke, voiced an argument that there was a theoretical limit to how precisely we can measure the speed and position of an electron (or any other particle, for that matter). According to the Uncertainty Principle, the more precisely we know an electron’s speed, the less precisely we will know its position, and vice versa.
The reason for this intractable uncertainty has nothing at all to do with scientists’ instruments. Even if scientists could use perfectly precise instruments (which don’t exist anyway), they would never be able to break past this barrier. No matter what, nature prevents us from knowing both the speed and location of an electron with exact certainty.
Of course Heisenberg couldn’t really use his Uncertainty Principle to claim ignorance about the location or speed of his car. The Uncertainty Principle doesn’t really apply to objects above the atomic scale. Heisenberg would have known this: I think he was just trying to get out of a ticket.