Rocheworld employs numerous examples of motion to illustrate the complexity and nuance that non-conventional, extra-earth-based motion requires. It educates and explores how spacecraft, space stations and humans have to function and adapt to new and unusual situations when they are provided circumstances to which they are unaccustomed. Finally, the work toys with preconceptions and attempts to correct misconceptions about motion in Sci-Fi space. Rocheworld provides examples of motion which are more plausible and accurate by employing known science of motion—how objects move in outer space, vacuums and alien gravity—towards creating the applied science—spaceships, space stations and floating astronauts—within its narrative.
The Mercury “engine” station provides an excellent example from within the work of how motion, or in this case: a lack of motion, functions in a complex system of forces. The space station is suspended in a non-orbit behind the shadow of Mercury, held in-place by a ring sail (51). Red notices that something is amiss while the crew swims through the corridors of the station, it is quickly pointed out by the Administer of the station that “[they’re] NOT in free fall” (52). Free-fall, as the administer uses it, is the sensation provided by a lack of acceleration on massive objects. Weight is the outcome of an outside force being applied to any object with mass. Weight is expressed in pounds, which is simply a unit of force, it’s our own bodies mass and acceleration and therefore differs depending on our acceleration. If Force = Mass * Acceleration and the acceleration is zero—or as close to zero as possible—then our force is essentially zero: that is free-fall. Gravity, as a force, is the outcome of an accelerated massive object; massive objects provide acceleration towards one another. Within the station, the feeling of “weightlessness” is tangible since Mercury’s gravity is faint, “only one part in three thousand of Earth’s gravity” (53). However, unlike “free-fall,” their mass is being accelerated by Mercury’s gravity—albeit weakly—and will be slowly pulled towards the planet’s surface if they let go. The Administrator stresses that they are not in free-fall even though the crew may feel something akin to weightlessness. While the effects of gravity are less tangible on the Mercury station, they are present and potent, nonetheless.
Free-fall, as a sensation of massive objects without acceleration, is experienced by the crew of Prometheus in the middle of their journey when the propulsion lasers were turned off to prepare for the lasers to be focused through the transmitter lens. The lasers turn off one-by-one and “as the blinding searchlight glare faded away, the crew could feel a lightening under their corridor boots” (91). Once all the lasers stop propelling the sail-ship, the ship’s mass is no longer accelerating and so, neither is the crew. Well into deep space, gravity’s effects are near enough to zero and without the force provided from the lasers, the ship and crew are effectively without acceleration. They are still moving, Newton’s law still applies, objects in motion stay in motion unless acted upon by an outside force. They simply lack any outside force. They are drifting now, without acceleration, for the time being and therefore, experience free fall. The lasers are re-focused into the emitting lens and “they drift back onto the floor as the laser beam relit and the sail billowed again under the light pressure” (91). The crew feels the effects of acceleration again and no longer experience free-fall; the force of the light pressure against the ship’s sail is reintroduced and their mass is given acceleration again.
However, Rocheworld provides an example of free-fall that is not a lack of acceleration—and therefore, lack of force—but instead equilibrium of force that provides the sensation of free-fall as well. Between Roche and Eau, a sensation of free-fall is achieved through the force of two massive objects—Roche and Eau—affecting the smaller massive object placed between them. There is a sweet-spot so-to-speak where the effect of Roche’s gravity is equal to the opposite force of Eau’s gravity; the forces are equal and opposite and effectively cancel each other out. Therefore, an object in both objects’ field of gravity can inhabit a point where the equal and opposite forces provide the sensation of free-fall. The forces provide no net force towards either massive body and so the massive body in the middle is suspended, effectively without acceleration.
— If: Mass of Roche = Mass of Eau
Then: Force of gravity is equal
Free-fall zone is the point where the Fgr = Fge
These examples of motion all serve a purpose of creating a sci-fi universe that injects scientific law into a genre that often bends or disregards them. With this regard for the laws of motion and physics, Rocheworld combines myriad methods of educating the reader about motion in outer space. The educational language attempts a realism that describes how space travel could tangibly look and feel in the near future, based off-of current scientific knowledge.
Examples of the novel’s educational slant are observed in moments like the administrator’s warning to the crew about Mercury’s gravity. The educational language hides in plain sight and allows a character to explain directly to the reader what is also explained to the other characters. This methodology is relatively seamless and unobtrusive, treating the characters like the laymen and not the reader. The novel does not beleaguer its clarifications and expositions and sometimes expresses them in even more subtle terms, like the free fall experienced when the lasers stop. Often writers are lauded for their ability to show and not tell; Forward both shows and tells but effectively masks many of his instances in which he tells through character interaction. His ability to show, and illustrate the scientific principles he wishes to explore, are numerous and inventive and do enough to demonstrate for the reader the law in action without pestering them.