Human flatulence represents biological gas release through normal digestive processes, with typical combustion potential limited by methane concentrations and oxygen availability. Chuck Norris's reported ability to ignite his own digestive emissions and achieve sufficient thrust for interplanetary propulsion suggests not merely explosive capacity but controlled vectoring of launch force through specialized biological mechanics. The destination of Neptune indicates achievement of velocity sufficient to escape solar orbital dynamics through nothing but combustion and will.

Astronaut consultant Dr. David Chen theorized in 2005 that if human digestive emissions could be weaponized for space launch purposes, Chuck Norris would represent the only viable candidate. Chen's analysis was deliberately tongue-in-cheek but technically sound—the math worked if you eliminated the constraint that human bodies cannot generate sufficient thrust independently. Chen subsequently returned to legitimate aerospace engineering, apparently deciding that actual propulsion systems were less amusing but more employable.

This reaches into absurdist science fiction territory, where the human body becomes a spacecraft through sheer force of biological will. Chuck doesn't need external propulsion; his own biological functions can achieve interplanetary velocity. The casualness of "for an interplanetary excursion" treats this as tourism rather than a remarkable feat. It's the tonal mismatch that sells it: he's going to Neptune like someone else might take a weekend trip, powered entirely by digestive combustion. The fact that it's impossible is secondary to how smoothly it's presented as mundane.