Fiction vs. Physics

Fiction vs. Physics

How Sci-Fi Negotiates With Reality

The Handwave Spectrum

“I worked out the equations for what a rotating black hole would really look like. Then Chris Nolan said, ‘Make it beautiful.’ What surprised us both is that the accurate version was the beautiful version.”

— Kip Thorne, Nobel Laureate in Physics, on consulting for Interstellar (2014)

Science fiction exists on a spectrum of fidelity to physics, and every position on that spectrum serves a different storytelling purpose. At the hard end stands The Expanse, which refuses FTL entirely. Ships in The Expanse obey Newtonian mechanics with brutal realism: they flip and burn, high-g acceleration crushes bodies, and the lag between Earth and the outer planets creates political fractures measured in light-minutes. There is no warp drive, no hyperspace, no handwave. The result is a universe where the Belt’s resentment of the Inner Planets feels viscerally real because the distances that separate them are real. Then there is Interstellar, where Kip Thorne — the Caltech physicist who would later win the Nobel Prize for LIGO — insisted that every visual depiction of the black hole Gargantua and the wormhole be derived from actual solutions to Einstein’s field equations. The wormhole in Interstellar is not a glowing portal. It is a sphere, because that is what a three-dimensional aperture in four-dimensional spacetime actually looks like. The rendering was so accurate it produced a publishable paper in Classical and Quantum Gravity.

Move toward the middle and you find Star Trek, which invented technobabble as an art form but maintains an internally consistent ruleset: warp factors have defined speeds, dilithium crystals impose real constraints, and the warp core can breach under stress. Trek’s FTL is not real physics, but it behaves like a technology with rules, limits, and failure modes, and that consistency lets the audience accept it. At the far soft end is Star Wars, where hyperspace is functionally magic — ships punch it and arrive where the plot needs them. And that is perfectly fine, because Star Wars is not about physics. It is about mythology, destiny, and laser swords. The handwave is the correct choice for the story being told. Doctor Who goes further still: the TARDIS violates physics so cheerfully and completely that it becomes the joke, the delight, and the point. Every position on this spectrum is valid. The question is not “how much physics do you include?” but “how do your choices about physics serve the story?”

When the Constraint Is the Story

“He who controls the spice controls the universe.”

— Frank Herbert, Dune (1965)

The most compelling science fiction does not merely include FTL mechanics — it uses their limitations as the engine of its drama. Battlestar Galactica’s FTL jumps are instantaneous, but they require complex calculations that take time. The standout episode “33” is built entirely on this constraint: the Cylons attack every 33 minutes, the crew must calculate and execute a jump each time, and the accumulating exhaustion and error become the entire dramatic arc. Without the calculation time, there is no episode. The constraint is the story.

Dune takes this principle to civilizational scale. Frank Herbert did not merely invent FTL travel — he made it dependent on a single substance, the spice mélange, found on only one planet, Arrakis. The Spacing Guild’s Navigators require spice to fold space safely, which means that whoever controls Arrakis controls all interstellar travel, which means every political conflict in the entire saga flows from this single bottleneck. Herbert understood something profound: the interesting question is never “can we go faster than light?” but “what does it cost, and who pays?” The Expanse achieves the same effect through absence — without FTL, the solar system becomes a pressure cooker of competing factions separated by months of travel, and every decision about resource allocation carries the weight of those distances. The best science fiction writers understand that a technology without constraints is not a technology. It is a wish. And wishes do not generate drama.

This section has covered a lot of ground — from the warp drives of science fiction to the warp metric of general relativity, from hyperspace lanes to the Casimir effect, from jump calculations to quantum inequalities. The honest summary is this: we do not know how to travel faster than light. No one does. No experiment has ever demonstrated superluminal travel of matter or information. The speed of light remains, as Einstein established in 1905, the universe’s absolute speed limit for anything with mass moving through space. That much is settled physics, confirmed by over a century of experiment.

But we now know enough to describe specific ways in which it might not be impossible — and that distinction matters enormously. The Alcubierre metric is a valid solution to Einstein’s field equations. Negative energy density exists, demonstrated by the Casimir effect. Wormhole solutions to general relativity exist, first described by Einstein and Rosen in 1935 and made traversable by Morris and Thorne in 1988. The gaps between theory and practice are in energy and materials, not in the laws of physics themselves. This is not the same as saying FTL is impossible. It is saying we have a map but no vehicle. The map is drawn in the language of general relativity, the most precise and well-tested theory of gravity ever constructed, and it shows routes that are permitted by the geometry of spacetime. Whether those routes can ever be traveled is a question for future physics, future engineering, and perhaps future materials science that has not yet been imagined.

Fiction got there first, as fiction usually does. Warp drives appeared in science fiction decades before Alcubierre put pen to paper. Wormholes were a narrative device before they were solutions to field equations. And the best fiction did it by respecting the constraints rather than ignoring them. The stories that endure — Dune, The Expanse, Interstellar, Battlestar Galactica — are the ones that understood that the physics is not an obstacle to good storytelling but the foundation of it. The universe has rules, and those rules create consequences, and consequences create drama. If you want to write about faster-than-light travel, the most interesting place to start is with the reasons it should be impossible. That tension — between what physics forbids and what physics might permit — is the beating heart of every page in this section. It is also, not coincidentally, the beating heart of The Quiet Threshold, a novel about the Fermi Paradox and the ultimate FTL question: if travel between stars is possible, why haven’t we heard from anyone?

Further Reading