Soon I realized I’d need the computers’ clocks to be as in-sync as possible, which in turn requires one-way latency calculations. I spent an hour diagramming with pencil and paper until I convinced myself it was mathematically impossible or I wasn’t clever enough to find the solution.
Looking back, I was more worried than I should’ve been about this (wired latencies are usually far less than 5ms, which for sound is ~1.5m) and less worried than I should’ve been about the fact that thunder isn’t anything close to a point source of sound.
Latency caused by the speed of light is a tangible and impactful factor in our lives!
It's amazing that something so incomprehensible (3x10^8 m/s) can actually be experienced.
Quick google search yields: $3.50 for 1L of He vs $0.30 for 1L of H2. So roughly 10 times more expensive.
Plus, liquid helium is produced as a byproduct of some natural gas extraction. If you needed volumes beyond that production, which seems likely if you wanted to switch the world's data centers to it, you'd be stuck condensing it from the atmosphere, which is far more expensive than collecting it from natural gas. I haven't done the math. I'm curious if someone else has.
Initial cost is high but running it should mostly just incur energy costs if it’s well designed.
I was able to find "1 gallon of liquid nitrogen costs just $0.5 in the storage tank". That would be about $0.12 per 1L of N2.
Nitrogen won't get you below 10°K, tho. It's solid below 63°K (-210°C).
You know things are getting expensive, when superconductors are rated "high temperature", when they can be cooled with LN2...
Helium (He2) is _practically finite, as we can't get it from the atmosphere in significant amounts (I think fusion reactor may be a source in the future), and it's critically important for medical imaging (each MRI 35k$/year) and research. You also can really store it long term, which means there are limits to retrieval/recycling, too. I sincerely hope we won't start blowing it away for porn and Instagram.
On the moon you have no atmosphere to do it with radiators with fans, so I gues you would have to make huge radiators which simply emit the heat away as infrared radiation?
Exactly. You can still transport the heat efficiently away from the computer using heat exchangers with some medium, but in the end radiators with a large enough surface area will be required.
Works well enough on the ISS, so I imagine it'd work just as well on the Moon.
Radiative heat loss scales with the fourth power of temperature. I don't know what temperature the ISS radiators are but suppose they are around 300K. Then I think the radiative surface to keep something cool at 10K would need to be 30^4, or 810000 times larger per unit heat loss. So realistically I think you would need some kind of wacky very low temperature refrigeration to raise the temperature at the radiator, and then maybe radiate the heat into the lunar surface.
And that only if you use the soil for cooling, which is non-renewable resource. If you use radiators, then you can put them on a satellite instead with much lower ping.
Astronaut DRIs?
Who volunteers as the original?
Once this can be done at the temperature of liquid nitrogen, that will be a true revolution. The difference in cost of producing liquid nitrogen and liquid helium is enormous.
Alternatively, such servers could be theoretically stored in the permanently shaded craters of the lunar South Pole, but at the cost of massive ping.