It's a science-fiction TV series based on a book series that I have never read. It's great fun, though I still fault the science. Sets are great, props are great, cast is great, characters are strong and the story is good -- but basic fiddlin' details, like which way is "down" on (and docked to) a spinning space station, how long radio waves take to get from, say, Earth to the Outer Planets (hours!), transit times even with a constant-boost drive (which they don't really have) and the goofiness of "acceleration drugs" make it more of a graphic novel come alive than a book-turned-TV-drama.
That said, Firefly had as many physics and technology howlers as The Expanse, if not more;* this doesn't make either one unwatchable or less fun, just check your skepticism at the door and bring popcorn! It's about halfway through the second season and available via Amazon and probably other on-demand services, so there are big blocks of story to enjoy if you haven't already.
* Each one has Big SF Exceptions, things essential to the plot that make no sense at all -- Firefly's possibly-FTL drive system, The Expanse's Big Spoiler I Won't Mention. You have to allow those for most SF. And little-to-obscure things can be wrong if well-sold (I loved The Martian but the math doesn't work at several points in the film. Sorry, he didn't make it). But don't cheat high-school physics!
2 months ago