Let's read GURPS Alpha Centauri

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I might just be a random online wanderer who came in from the internet, but I wouldn't mind taking a stab at a Let's Read for the GURPS sourcebook sometime. The only other place I've seen it examined in detail is this review on Age of Ravens.

Apropos of nothing, I'm also involved in a couple of SMAC fanfic projects. Here's something I wrote after the Super Bowl.
 
I used to love playing SMAC back in the day. You know it had two short stories, three novels and a comic book too?

I’m sad it’s owned by EA who’ve been content to let it rot in obscurity.

I’m even sadder that Beyond Earth was such a dud.
 
Tangent for fans of the videogame:

There's a mod called Thinker that revamps the videogame AI to the point it gets competitive without resorting to cheating like in vanilla. The mod also makes some subtle rules changes that fit the game spirit IMO, like making probe infiltration to expire after a time (based on factions' Police and Probe ratings), and making Research more costly and slower but at the same time factoring-in allies technologies in the process (so if you're currently researching a tech an ally has, it receives a small speed bonus). It also improves the player's AI so automating terraformers and governors become actually viable now.

You can find the mod here: https://github.com/induktio/thinker

Edit: oh, and I opened a thread in the Media forums to talk about the videogame, if anyone is interested.
 
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Just in case someone has missed it, I'm a huge* fan of Séadna Séadna 's reviews:grin:!


*Though I'm trying to slim down, but abstaining from sugars is hard...:tongue:
I did the calculations. The book just says the air is unbreathable a few hundred feet up but doesn't really go into details. I had to work out the acclimatisation time, and the specifics of the partial pressures of nitrogen and oxygen in order to see how bad the level of nitrogen narcosis and oxygen deprivation was. It was from prior knowledge, it's not in a GURPS book.

If anybody ever wants to do this for a fictional planet you'll need (if you've no interest in maths, see the 2nd paragraph of point 4 for something that might still be interesting):
  1. The Barometric equation, to get the pressure at various altitudes. Adjusting it to other planets means changing the gravitational acceleration, the pressure at sea level and the average molar mass of the air. The latter is worked out from the relative mixtures of gases in the atmosphere and requires a bit of chemical knowledge.

  2. The partial pressure equations to get the partial pressure of each gas. This only takes the absolute pressure (from above) and the relative concentration of that gas

  3. Aveolar gas equation. This is required only if you want absolute accuracy and models the difference between the partial pressure out in the air versus that in the lungs. For most planets only going to stage 2 should be enough. For Alpha Centauri's planet it isn't because of the presence (1% of atmosphere) of toxic gases and because going to the second stage didn't give a completely clear answer to nitrogen narcosis because it was borderline.

  4. If you want to be very very accurate (this wasn't necessary for Planet) note that the pressure on most planets usually has "layers" where it suddenly drops rapidly. So for instance on Earth you can't use the pressure at ground level to work out the pressure at 12km up because of a sudden pressure drop at 11km (8.5 km on Planet). Instead you have to use the pressure at 11km as the "new" ground level for the barometric equation.
    This doesn't matter on Earth or Planet since nobody would live far up enough for it to be relevant. It might matter on a world with very high pressure as it could mean the pressure is low enough up near the summits of massive mountains to be livable. So you'd have the Valleys between mountains where the pressure is lethal, with cities encircling the summits.
    The pressure drop off points on Earth are 11km, 20km and 32km. On Planet 8.5km, 15km and 25km. This changes how airflight works on Planet. Which I'll get to later.
Thank you. I wish GURPS books actually had such explanations:thumbsup:!

Hmm, what if we were to drop below sea level, say in valleys or underground? How about if we were to raise oxygen content by, say, an additional 3%:devil:?
 
Found these AI images of the setting. More here: https://forums.civfanatics.com/threads/landing-on-alpha-centauri-ai-generated-images.682859/


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