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Comment Re:Yes. It is called "land subsidence" (Score 2) 442

Which makes sense. Sea level rise in the last 50 years has amounted to about 4 inches, probably not enough to make drains run backwards.

The way sea level rise will make itself known isn't through changes in day to day phenomena, but in exceptional phenomena like storm surge flooding. This is a place where inches may well matter. People plan around concepts like a "ten year flood" or a "hundred year flood", and this creates a sharp line on the map where there is no sharp line in reality. Depending where on the domain of the bell curve their chosen planning horizon is, a few inches could turn a ten year flood into a five year flood, which has immense practical implications.

When people way that there is nothing intrinsically worse about a globe that's four degrees hotter they're right. But *change* that undermines human plans represents a big challenge. Change also represents a big challenge to species populations that can't relocate on the timescale of change.

Comment Re:WIMPs (Score 1) 236

In fact all forces should get weaker with distance faster in an expanding space than in flat space.

That seems like quite an assumption on your part, if I'm understanding you correctly. We can't just assume that all properties of spacetime are scaling evenly - if they did, then we'd perceive no effect at all.

But perhaps I'm misunderstanding you.

Comment Re:Still photos (Score 1) 447

Some pilots would probably still want the ability to override the limits in an emergency if they feel that they can handle the situation better than the autopilot (for example, if the plane is crashing and the pilot wants better control over where/how to bring it down). If so, then you should make it a possibility to disable the limits, have it such that only *ground* can disable the limits. This would of course impose a delay, but at least overriding the limits would remain a possibility.

Of course, a pilot may try to trick ground into disabling limits (such as pretending to be going down or pretending to have a malfunction), so ground would need as much data as possible to assess whether the situation is legit. Might be tricky... best would be to err on the side of caution and only remove limits if everyone is absolutely sure that this is appropriate, if there's any doubt the answer should be "no".

Comment Re:Wrong Focus (Score 1) 132

Not today. But maybe in the future. If you can develop a crazy-power-dense energy source and cooling system, you could probably do it with a MPD thruster. The research I've seen on MPD thrusters operating in pulsed mode yields crazy output relative to the mass of the thruster. But you can't run it continuously because it'd overhead and take way too much power. But who knows about the future? There's the potential for extreme heat conductors like isotopically pure diamond, maybe a some kind of fission fragment reactor with a deceleration grid for power...

(of course, if you have a fission fragment reactor, at least when you're in space itd be best just to jet your fragments rather than use them to power a MPD thruster...)

Comment Re:It is (Score 5, Interesting) 132

I hope they simulate propane too, not just methane. Propane has some really interesting properties as rocket fuel but have (like methane) never gotten much research. But now there's a big rush to research methane as fuel based on the concept of generating it on Mars - so propane still gets left in the dark.

Methane's ISP is only very slightly better than propane's - 364,6 vs. 368,3 at a 100:1 expansion into vacuum and 20MPa chamber pressure. But propane at around 100K (note: not at its boiling point, 230K) has far higher density (782 kg/m^3), closer to that of room temperature RP-1 (820 kg/m) then that of boiling point methane (423 kg/m^3), which reduces tankage mass and cost. 100K propane's ISP is of course better than RP-1's 354.6 in the same conditions as above. Plus, its temperature is similar enough to your LOX that they can share a common bulkhead, which reduces mass further and simplifies construction.

Hydrogen generally is the easiest fuel to synthesize offworld. Methane is generally second, and propane third. Hydrogen is often rejected as a martian fuel because of the tankage and cooling requirements. Methane can be kept as liquid on Mars with little cooling in properly designed reflective / insulated containers - but so can 100K propane, in similar conditions, but with significantly smaller tankage requirements.

It seriously warrants more research, I tell you what.

Comment Re:HOWTO (Score 1) 1081

some people do deserve it. timothy mcveigh for one example

McVeigh? Oh, you mean the freedom fighter who was murdered by the government for his attempt to start the War of Liberation of the American People from the Curse of Washington? The future will not look kindly on the people who murdered this martyr, and the supporters of that government will be first up against the wall when the Revolution comes.

It looks a bit different from the other end of the telescope, doesn't it?

Comment Re:This whole issue needs to be buried (Score 1) 365

Once they've done that, their debt to society is paid in full.

Says who? There is no natural law that says wages+taxes are the end of it. In fact that isn't even the case today, where companies are required to provide things like safety equipment, toilet facilities and so forth. You are delusional if you think they do that stuff out of the kindness of their corporate hearts.

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