If you’re a “hard” sci-fi nerd, Syfy’s The Expanse is the show you should be watching. Based on the novels by James S. A. Corey, the series is a political thriller about rising tensions between military and civilian powers in a colonized solar system. The second season premiered last night, proving the show is still great. But beyond its other strengths, the role science plays in its narrative is a big reason why it’s such a success. The Expanse is a better sci-fi show than most because it feels like a plausible future–what we know about the universe informs the story rather than exists in service to it. 

What Goes Up…

The Expanse gets many minor details right (more on that below), but it understands the all-encompassing force of gravity better than just about any space-themed show or movie I can think of. Gravity is an inherent property of mass; more mass means more gravity. This relationship is what turns planets into so-called “gravity wells” that rockets must climb up from, and what makes empty space a weightless abyss. The distinction between planet and empty space is where most shows and movies stop with gravity. You can walk on Earth, you float in space. What The Expanse understands is that gravity never goes away, and that space travel is a constant tango with this fundamental force.

For example, when the main characters need to perform a “turn-and-burn” in their spacecraft, they understand that this means up and down are about to change directions, and get a lot more intense. What we feel as our own weight is dictated by how quickly we are falling towards something, and whether or not something gets in the way. On terra firma, we fall towards the center of the Earth at 9.81 meters per second per second. The Earth gets in our way, so we feel a force (our mass multiplied by how fast we are falling)–thus, our weight. During a turn-and-burn, the crew has to suddenly accelerate, and so their weight will change dramatically. This is why the travelers need “crash couches” and “the juice” that helps them deal with the increased g-forces: when a spaceship changes direction and punches it, you could instantaneously weigh thousands of pounds.

Mass and gravity are related, and so “Belters,” or those who live in the asteroid belt, grow up with human bodies unprepared to cope with non-human weights. That’s why these rock hoppers are taller and experience a litany of health issues. Spines really do elongate in space–astronauts aboard the ISS grow centimeters as the pressure on their vertebrae relaxes. Hearts become more spherical, eyes and faces bulge with fluid, cosmic radiation pierces DNA… Living in space, like living in the Belt, really would be as oppressive as The Expanse imagines.

Space Is Big

Well, duh. But you’d be surprised how many shows and movies don’t seem to grasp this basic fact. If we ever branch out from Earth, interplanetary travel isn’t going to be as easy as Star Trek or Star Wars portrays. Space is so big that reasonably fast travel within our technological scope will still take a long time, like a recapitulation of explorers discovering the new world. The Expanse knows that even with our fastest craft, getting from the Earth to Mars or the Belt would take days, if not weeks or months depending on the path. Many space stories hand-wave away this restriction with warp drives or faster-than-light travel; The Expanse does not. It challenges itself to make space travel exciting and interesting, and to produce opportunities for character development.

Think of every spaceship you’ve ever seen in fiction. How does it move? It accelerates forward until it reaches its destination, right? That’s a death sentence. Because there isn’t any air in space, there is no drag, and so every time a spaceship accelerated, it would attain and keep a higher and higher velocity. Unless a ship decelerated, and fired thrusters in the opposite direction to slow back down, it would impact a space station at many kilometers per second and obliterate it. The Expanse explicitly mentions deceleration burns in its dialogue to ground the universe (solar system) of the show. Attention to detail doesn’t just stop at the big story elements either.

Sweat the Small Stuff

It’s hard to nail down what about Blade Runner or Mass Effect or Neuromancer makes the fictional worlds feel real, but sweating the small stuff is certainly part of it. Getting little details right, details audiences may only subconsciously notice, is what erects the scaffolding of believability in the mind. The Expanse hardly has a corridor or airlock that doesn’t seem thought-out and realized.

When spacecrafts approach a space station, for example, you’ll see them tumbling instead of proceeding ahead in a perfectly level line like the starship Enterprise. At a constant velocity, it doesn’t matter for your sense of direction if the ship isn’t perfectly stable, and making it so would require constant adjustment, using fuel you need to conserve. Tumbling is the more efficient, and more accurate, way to travel through space. Come to think of it, The Expanse is probably the only sci-fi show to get this right.

Then there are the ships themselves. Look at them closely…they don’t really look like sci-fi starships, do they? They don’t have wings or fins or flourishes. The Expanse‘s craft look like giant rockets peppered with stabilizing thrusters–exactly what you’d want in a solar system strapped for resources, especially if these crafts never enter an atmosphere like Earth’s.

In space, no one can hear you scream. Any science nerd knows that the rest of that tagline would be, “…because there is no air to transmit the pressure waves we interpret as sound.” It’s not very catchy, I get it. The same logic applies to explosions in space: they should be silent. They are on The Expanse. The show also takes the time to work around the lack of “anti-gravity” technology, something that will likely never exist. A pair of headphones pulled from the ears will just hang there, and any movement on deck while a ship is not accelerating requires magnetic boots. When all these details pass the mental check of “is that really possible?”, characters and drama are relatable on a show set hundreds of years in the future.

Science Elevating Story

The Expanse of course doesn’t get everything right, nor should a fictional story have to, but it definitely is more grounded in science than most. Understandably, writers have to cut corners to keep the narrative engaging, and often science falls by the wayside. When a story does take the time to ground itself, however, it makes for better world-building and a better subconscious acceptance of the plausibility, allowing you to imagine yourself floating among giant ice-laden asteroids waiting to be cracked.

Getting to and colonizing space will likely be the most epic thing humans ever do, but the details of doing so can come off as boring, even mundane. And so, many space operas skip them altogether. But science in service of the story, when implemented as seamlessly as we see in The Expanse, is less of a hurdle and more like a twist most audiences never considered, but can now appreciate for its inclusion. We feel smarter as viewers, and we feel as appreciated as the science is, when The Expanse takes the time to get the science right.

The Expanse is currently airing its second season on Syfy.

Images: Syfy; NBC Universal