Explain SMBC — the wiki for Saturday Morning Breakfast Cereal

The Joke

The comic presents a single-panel scenario with a caption at the top reading: "If I were a pilot, I would make up new physics for every flight." Below, a commercial airplane is shown taking off while the pilot announces over the intercom: "And now, we jettison our center of mass, making us weightless so that we can fly."

The joke is that the pilot is inventing completely nonsensical physics to explain how the airplane works. "Jettisoning the center of mass" is physically meaningless -- you cannot remove a center of mass from an object, as it is a mathematical property of the mass distribution, not a separable component. Yet the pilot presents it with total confidence as if it were a legitimate flight procedure.

The Humor

The humor operates on two levels. First, there is the absurdity of a pilot who treats each flight as an opportunity for creative fiction about physics, inventing a different bogus explanation every time. Second, it plays on the reality that most airline passengers have little understanding of the actual physics of flight, so a confidently delivered but completely wrong explanation might go unchallenged. The comic also taps into the fantasy of being in a position of authority and using it purely for personal amusement -- making up fake science just because your audience cannot tell the difference.

References

The concept of "center of mass" is a fundamental physics term referring to the average position of mass in a system. It is an intrinsic mathematical property and cannot be physically "jettisoned" from an object.