Spaceships--how much IS a power point

[YankeeGamer]

The information here is absolutely stunning! I was figuring on volcanic vents being active--probably overactive--due to the tidal stresses when Earth was sent out of orbit. Yellowstone may wwll have blown, among others. Around underwater volcanic vents, life is probably the same is it has been.

Rule of Cool demands that the atmosphere be frozen, so the Enterprise can reach Europe after long voyage over the desolate Atlantic, but a sub plot or two about places where the air is not completely stable are always good. Kirk and Picard's ships had more than a few incidents where they were stuck in the space-time anomaly of the week...
Places like Hawai'i might have liquid air, or even sinkholes.

[Agemegos]

I am trying to imagine what conditions would be like at places on the surface warm enough that oxygen, nitrogen, water, and even rock are still liquid, bearing vapour pressure in mind. The issue is that the upper surface of the melt is exposed to vacuum, where I think any of the volatiles will boil and freeze, and the vapour blow away before condensing as frost and rime. One possiblity is a zone of warm bare rock surrounded by a counterscarp of ices. Another is a buried bubble of liquid air with a crust of frozen nitrogen, venting oxygen-rich vapour.

[Michael Thayne]

Going by the muzzle energy per second of a 2cm very rapid fire EM gun, an SM+4 power point needs to be at least 6 megawatts or so. If you go by grav guns you get a figure around six times that much.

[Agemegos]

Originally Posted by AlexanderHowl

Did the Sun die? Because there is no other way that it gets cold enough for nitrogen to freeze (the temperature must be below -210 C).

Earth was thrown out of the Solar System by the gravitational effects of a stellar close encounter, and has become an interstellar rogue planet.

With the insulation effects of nitrogen and the geothermal energy of the Earth (and the tidal energy from the Moon), I am not even sure that the temperature can get cold enough to cause nitrogen rain, much less nitrogen ice. Look at Titan for an example of a cold world with a nitrogen atmosphere.

Look at Pluto for an example of a world with nitrogen ice at the surface. It is well worth considering the surface and crust of Pluto in this exercise.

It might be even more valuable to consider Triton, which is given as the example of a "hadean" world in GURPS Space (4th edition). I note that the minimum bound on Triton's surface temperature is 35.7 K, close to Anthony's estimate of 35 K as the minimum surface temperature for rogue Earth to radiate the geothermal flux to space.

Note that the lowest temperature that gets considered in the GURPS Space world generation sequence is 50 K, which is the temperature at which a eutectic mixture of nitrogen and oxygen freezes. The generation sequence doesn't consider mixtures of liquid nitrogen and oxygen because a history of life in liquid water is necessary to produce the oxygen.

[Agemegos]

Originally Posted by Anthony

Maybe? I'm an amateur speculating.

Sorry.

Perhaps if this tangent were in a separate thread under some such title as

[Space] frozen Earth and other hadean worlds

it would attract more attention from contributors with real knowledge of the relevant planetary science and physical chemistry. I have sent a PM to YankeeGamer suggesting that he ask a mod to split posts numbers

23 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 44 45 46 47 48 49 50 51 52 54

into a separate thread with an informative title. Which he could do by reporting this post with a suitable comment.