"Flip right now and burn like hell and I can get us within 50,000 clicks," ship's navigator Ade Nygaard announces in the first episode of SyFy's fascinating space opera "The Expanse." The rest of the freighter Canterbury's crew looks appalled. A working stiff rolls her eyes.

"Oh great, then we'll all be puking in our crash couches while the cargo busts loose and scuttles the ship."

This snippet of dialogue sets up one of the most inventive scenes ever seen on screen in science fiction. Past movies and shows from "Star Trek" to "2001: A Space Odyssey" sidestepped the fundamental problems of space travel with imaginary physics or by skipping them entirely. "The Expanse," which aspires to be a sort of interplanetary "Game of Thrones," relishes them.

"The Expanse" lacks George R.R. Martin's endlessly compelling characters, but its world rivals the meticulous beauty of Westeros. In this future, humans have settled the solar system but gone no further. Outposts proliferate throughout the asteroid belt, and civilization thrives on Mars. The people of Earth live in luxury.

Like the British Empire at the height of its power, the United Nations saps its starving colonies of resources and spreads the wealth at home. Militarized, autonomous Martians challenge Earth's dominion in a simmering cold war. Belters, a sort of space proletariat, live meager lives with little oxygen or water and illness from childhoods spent in low gravity. But with all the furor of prewar Bundists, a workers revolution foments.

That far-flung society depends on a massive, high-speed freight system, of which the Canterbury is part. The ship and its crew are on their way to the dwarf planet Ceres with a huge cargo of ice when they hear a distress call. This prompts the choice to "flip and burn" — to turn the ship and blast its engines against the massive inertia hurtling the crew along their original course.

In most science fiction, this maneuver would be no big deal. How many times in four movies have we watched the Millennium Falcon perform barrel rolls?

Even the near-future flick "The Martian" features a giant NASA cruiser reversing course with minimal tzurus.

Acceleration scientist John Stapp hit 22 Gs during this rocket-sled experiment in 1954. He eventually set a world record of 46 Gs but suffered damage to his vision. Wikimedia Commons Not so in "The Expanse." In this universe everyone traveling through space has to deal with the overwhelming physical pressures that modern astronauts and fighter pilots experience in extreme situations like launch and landing. In fact, to account for the higher speeds of interplanetary travel and lower concern for human well-being, the pressures are even greater.

Thus the working stiff's unwillingness to change course. She's less worried about being late to Ceres than her bones shaking apart mid-turn (not to mention the ship around her). Unless we make massive strides in gravity technology in the next few centuries (a premise on which nearly all other science fiction rests) this is the reality future spacefarers will have to deal with.

In one scene, the captain warns his crew to expect "30 Gs" during an evasive maneuver. One G is the force of the Earth pressing on your body at sea level. If you've ridden a roller coaster, you may have experienced a few times that. Fighter pilots and astronauts withstand even greater forces, in the vicinity of 8 or 9 Gs.

But G-force doesn't act the same on your whole body. Solid tissues tend to stay in one place, but blood flows in whichever direction physics dictates. This can starve your brain and eyeballs of necessary oxygen. Pressure in the 15-G range can kill in under a minute.

The effects of space travel in "The Expanse." NBC Universal Pilots have a few tricks for dealing with this. G-suits squeeze their legs like vises, forcing blood up from their legs into their organs and brains. Flexing certain stomach muscles can help as well. But the most important pieces of that puzzle are strong hearts and avoiding sustained high-G maneuvers altogether.

Characters in "The Expanse" go to even greater lengths to survive the megaforces of moving through the solar system at high speeds. Before every turn or acceleration they strap themselves into crash chairs and put in mouthguards. Robotic metal pincers pierce their necks, supporting their spines and pumping a sickly, gelatinous goop into their bloodstreams. Presumably this keeps their essential fluids from sloshing around too much. The whole thing looks fairly unpleasant.

Who knows? Maybe gravity technology will improve so much in the next centuries that our spaceships will resemble the calm, collected bridge of the Enterprise. But from where we stand today, "The Expanse" might be the most realistic imagining of our spacefaring future to ever air on television.