2014-08-20
Explanation
The Joke
A child asks their mother: "Mommy, what is the fastest animal?" The comic then shows four different types of people answering this question. A "Normal Person" says "The cheetah." A "Biologist" says "A descending peregrine falcon." An "Engineer" says "Human being in an orbiting satellite." A "Physicist" says "Unspecified reference frame. Question invalid."
The Humor
The joke illustrates how different fields of expertise lead to increasingly pedantic and technically correct but socially useless answers to a simple question. The normal person gives the common, satisfying answer (cheetah). The biologist corrects this with a more precise answer -- peregrine falcons are indeed the fastest animals when diving, reaching over 240 mph. The engineer takes it further by noting that humans in orbit are traveling at about 17,500 mph, technically making them the fastest "animals." Finally, the physicist refuses to answer at all because without specifying a reference frame, the concept of speed is meaningless -- everything is both stationary and moving depending on your frame of reference. Each answer is more technically correct but less useful, satirizing how expertise can make people unable to engage with simple questions.
References
The peregrine falcon is indeed considered the fastest animal on Earth, reaching speeds over 240 mph (386 km/h) in a hunting dive (stoop). The International Space Station orbits at approximately 17,150 mph (27,600 km/h). The physicist's objection references Einstein's theory of special relativity, which holds that velocity is always relative to a chosen reference frame.