There appear to be liquid water layers on many moons in the outer solar system, which experience significant tidal heating. There are many ways that deep liquid water can be detected. Ganymede, for instance, has an induced magnetic field, which requires a conducting layer. The best fit for that conducting layer is…

Many of the other Jovians contain huge quantities of water. The outer three Galileans are roughly equal mixtures of silicates and water ice, but Europa has a significantly higher density, so it's got a higher proportion of rock than Ganymede and Callisto. Ganymede is bigger than Mercury, with a density of only 2 grams…

Awwww, genuinely sorry :(

I did not find that extract to be at all well written (he said).

"Science fiction author Vernor Vinge has famously said that an ultraintelligent machine will be the last invention humans will ever have to make."

I also find it impossible to believe that Russia will actually do this!

Exactly! Dumb films and TV shows where the aliens invade for our water annoy the hell out of me; it's a basic case of Not Doing The Research due to pure laziness. All those thirsty lizards could just grab a couple of ice moons, which don't have any apes to shoot back.

It should be stable enough on human timescales. I seem to remember that if you gave the Moon a nitrogen-oxygen atmosphere with 1 bar surface pressure, it would be tens of millions of years before the pressure dropped significantly due to thermal escape. Something like 10^8 years to lose 200mb? So a Martian atmosphere…

I seem to remember Europa was fragmented, and parts of it were used to terraform both Mars and Venus in Greg Bear's The Forge of God.

Quite.

I haven't heard of Melba Ketchum, but it turns out she's on Facebook. Apparently Melba has encountered Bigfoot several times. She says they're about ten feet tall, peaceful and gentle.

Azkaban is the only one of those films I like (and the only one I've voluntarily seen more than once).

Ah, thank you. I've been wondering that ever since 2312 was announced. Although KSR recycles a lot of ideas, I suspected 2312 was a semi-sequel - it's even got an AI called Pauline, like John Boone's AI in Red Mars.

I should have scrolled down - we had much the same thoughts.

Can they? I'm honestly not sure. The androids have circulatory fluid, which is clearly under pressure (it spurts all over the place when Ash has his head chopped off). Now they could well be more durable to extremes of pressure than humans, but because of their circulatory fluid it's reasonable to expect that they…

That's pretty much my understanding. Of course, the last time I was in a lecture on cosmology or general relativity, nobody had the faintest inkling that the expansion might be accelerating, so my knowledge of the matter is *very* redshifted!

I've always felt a little left out, because unlike the majority of my friends I just don't enjoy Tim Burton movies, and I never have. I'm not quite sure what it is about them, but he has a very particular style, and that style simply does not work for me. I just find it... irritating.

I really enjoyed reading Shadow 19 and Passengers, so my eyes lit up when I heard Jon Spaihts was writing for Prometheus.

I saw some of these meteorites in Windhoek, and I believe Peter Watts and Caitlin Sweet have matching rings made from them.

Well w is the equation of state, the ratio of pressure to energy density. So for non-relativistic stuff like cold dust, w = 0 (it dilutes proportional to the volume, which is what you'd expect) and for radiation, w = 1/3.