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Comment by outworlder | Hacker News Reader

There goes the water rationing narrative in The Expanse...

No, it doesn't create a plot loop. The book explains that all of the H2O on Ceres was used to apply spin to Ceres to create artificial gravity. This is a symbol of Inner Planet's dominance over the Beleter's, because a _real_ Belter would never trade precious water for artificial gravity. This is mentioned fairly subtly in the first book, and is easy to miss while taking in the rest of the world.

In addition the spinning up of Ceres is often mentioned as one the of many engineering feats attributed to Tycho.

EDIT: For scientific context to my statement H2O can be turned into really good propellant. Two of Blue Origin's engines run on Liquid Hydrogen and Liquid Oxygen for example.

> For scientific context to my statement H2O can be turned into really good propellant

Note that in The Expanse universe, water isn't usually used as propellant, but simply as reaction mass. All we know about the actual propellant is that it's used in fusion reactors and is surprisingly efficient.

> All we know about the actual propellant is that it's used in fusion reactors and is surprisingly efficient.

Since we're being specific with terminology, if it's used in a fusion reactor, it's not a propellant, since propellant is a combination of chemical fuel and oxidizer.

> Note that in The Expanse universe, water isn't usually used as propellant, but simply as reaction mass. All we know about the actual propellant is that it's used in fusion reactors and is surprisingly efficient.

It's actually ambiguous if Ceres was spun up before the Epstein drive was invented or not. If the H2O was consumed in an Epstein drive (fueled by D-He3 fusion) then only Hydrogen was consumed to produce thrust. What's not ambiguous is that the H2O on Ceres was consumed

We know that mars was colonized 200 years before the Epstein drive was invented. We know that the OPA was founded about 100 years after the Epstein drive was invented, and that 130 years after the Epstein drive is when the main story starts. We know Earth was the first owner of Ceres. We don't know how old Tycho is, other than Fred Johnson was not the first leader of Tycho.

It's an open question on to what extend the belt had humans in it during the 200 years humans were on Mars before the invention of the Epstein drive. It's safe to say that answer is somewhere between more than none, and less than what is shown during the opening of the series. It's highly plausible Ceres was spun up during that time.

I had missed that Ceres' gravity is due to its spin.

Does that mean humans are living upside down in their tunnels compared to Earth?

And if that's the case, surely a spin that's greater than the local gravity should shatter the planet itself as the matter has no reason to stay concentrated around its core right?

Am I missing something?

No. The fact that Ceres is a sphere implies that its scale is large enough for its material to behave as if it were a fluid and so reach hydrostatic equilibrium. Without serious engineering it would indeed come apart if you spun it up.

I vaguely remember something about Tycho Corporation wrapping cables around it and making it stronger, but maybe I'm confusing that with a Scott Manley video about Ceres in the Expanse.

But yes, walking feet towards the surface of Ceres, head to the core. The core is also where the poor people live in The Expanse, because the gravity is less/worse there together with weird Coriolis effects like this https://www.youtube.com/watch?v=ryrGPjyKhO4

The authors of The Expanse published an article last year acknowledging and paying tribute to the mission ("How a NASA robot messed up our science fiction"): https://www.nationalgeographic.com/science/2019/02/dear-dawn...

Love them even more for that.

Nah, kopeng mi; inyalowda, dey stole da owkwa from beltalowda!

Oh man, that was perfect :)

Dey stole ere luf, sasa ke.

Miller to Diogo: "Don't mess wit de owkwa!"

The book(s) acknowledges it's made of ice. You can't drink your entire habitat.

All the water on Earth was drunk at some stage wasn't it?

I suspect that isn't true, but it is an interesting question. There is a lot of water on the planet, some of it spends long periods locked up out of reach of drink ability.

I would guess that at most water has been drunk multiple times, but that there is some miniscule a fraction that moved between icecap, permafrost and deep water table and has avoided being consumed by an animal since it arrived on earth.

I would be interested to read a mathematical estimate of how many 9s of water on earth has been drunk at some point.

There is a related interesting observation that every breath you take contains on average one molecule that was breathed out by Julius Caesar in his dying breath:

https://www.sciencefocus.com/planet-earth/are-we-really-brea...

Avogadro’s number is very large.

Somewhat related XKCD What if: https://what-if.xkcd.com/74/

drunk by a human or drunk at all? I'd suspect that not all water has been drunk at all, but lets cover the human part.

Lets say the average human drinks 3 liters per day and lives 80 years (3 * 365 * 80 ) = 87,600 liters per human.

there have been about 100 billion humans so 100 b * 87600 =8,760,000,000,000,000 liters have been drunk.

there are about this many liters in Earths 5 oceans (source google search): 1,400,000,000,000,000,000,000

Assuming no one has ever drank the same amount of water before, 8,760,000,000,000,000 < 1,400,000,000,000,000,000,000

It sounds fairly certain that not all water has been drunk by a human, even if my math is way off

The point is that in being drank, water is not destroyed.

In any particular glass of water, supposedly almost all of it was drunk by a dinosaur.

https://youtu.be/KK64DqpIy0s

My recollection was that Mars raided Ceres for ice, prior to or while spinning it up. It would take a hell of a lot of mass drivers, all pointed in the same axis, to spin up a dwarf planet.

The title says "water" but the article says "brine". Don't count on it.

Assuming for a moment the technology/scifi world of The Expanse, one thing that doesn't seem to be a scarce resource is electrical power, due to plentiful nuclear reactors. Wouldn't it be possible to flash brine into steam and separate the h2o from the salt, storing the salt in solid cubes or something?

Brine is pretty corrosive, more so if you heat it up, but you you could do that, yes.

I thought Co[r]vid-19 had already blew most of The Expanse out of the water.

Pretty sure ravens aren't related to this discussion ;-)

Got my eclipse phase wires crossed https://eclipse-phase.fandom.com/wiki/Blackbird_1e

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