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Comment: Re:Yes. It is called "land subsidence" (Score 1) 116

by hey! (#49366771) Attached to: Experts: Aim of 2 Degrees Climate Goal Insufficient

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) 216

by Rei (#49366735) Attached to: Dark Matter Is Even More of a Mystery Than Expected

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) 278

by Rei (#49366707) Attached to: Why the Final Moments Inside a Cockpit Are Heard But Not Seen

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) 78

by Rei (#49366605) Attached to: SpaceX's New Combustion Technologies

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 1) 78

by Rei (#49366565) Attached to: SpaceX's New Combustion Technologies

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:Delivery drones (Score 1) 80

by rwa2 (#49366283) Attached to: How long until our skies are filled with drones?

Heh, it's funny, I think the exact same things about using a sea of trucks to drive around delivering everything... "imagine the sound, the inevitable crashes, the energy consumption". Every one pound package comes with several tons of vehicle and fuel to deliver it, stringing along a dozen other packages along for the ride.

Sure, trucks and trains make sense for long haul stuff, especially when the route would traverse weather systems. But we could certainly squeeze out a lot of inefficiencies by sending out the last mile via drone network.

Energy usage is actually pretty good... the drones are light relative to their cargo, so less overhead.
Batteries and electric motors have improved tremendously over the past few decades, more than double the energy can be converted into useful work nowadays with brushless motors.
Solar energy keeps getting cheaper and cheaper, down from astronomical a few decades ago (as in, they only made sense for satellites) to "competitive with natural gas" now (and they're practically giving away natural gas for free as a byproduct of fracking.

Comment: Re:Delivery drones (Score 1) 80

by rwa2 (#49366221) Attached to: How long until our skies are filled with drones?

We'll never get away from the fact that driving tons of trucks around to deliver a few pounds of goods is extremely energy intensive and has some nasty failure modes. What happens when a truck overturns on the expressway and wipes out a few minivans full of kids? We make new trucks and new kids, apparently.

hex drones have enough redundancy to cope with common failures. It will be interesting to see if robotic flying drones or robotic driving drones will come first. I would predict flying drones, since, other than "flying is hard", it's actually less complicated than trying to program driving drones to navigate road hazards. Especially, as you mention, since driving drones will probably need human supervision anyway, so it won't really be cheaper or faster than just making the delivery guy do the lifting.

Comment: Re:call it the Ukraine-2 (Score 1) 135

by circletimessquare (#49364607) Attached to: Russia Wants To Work With NASA On a New Space Station

What Russia did to Georgia in 2008 is a continuation of what Georgia did to itself in the early nineties

i stopped reading there

russia has no right to invade a sovereign country. do you understand? of course they have a "reason." do you have a functioning brain? can you see through their bullshit?

russia meddled in an *internal* georgian dispute that occurred within the internationally recognized borders of georgia. then it divided the country into a "new" bullshit country abkhazia

is it ok if the usa invades the mexican district of sonora and announces that it is a new country? why can the usa do this? uhhh... drug smuggling. yeah, that's our reason. perfectly good reason, totally understandable, right moron?

what was russia's reaons for invading georgia? guess what: it has no fucking right to invade and divide a sovereign country on those hopped reasons. do you understand what sovereignty is?

can the american fbi go into canada and arrest people? no? why not. can the us army occupy ontario? why not? because canada is a sovereign country, you dumb fuck

why do you think it's perfectly normal and ok for russia to invade and divide it's smaller neighbors? it's not normal. it's not acceptable

no country, anywhere in the world, does what russia did to georgia and ukraine without consequences. not south africa and mozambique. not china and vietnam. not brazil and uruguay. countries do not invade other sovereign countries and that's just normal and fine. do you understand?

if you do, continue speaking on this topic. but if you continue to assert russia invading and dividing georgia and ukraine is "reasonable" then you do not understand what the fuck sovereignty means and are therefore announcing yourself as a complete moron or a propagandized idiot on this topic and you should shut up

Comment: Re:call it the Ukraine-2 (Score 1) 135

by circletimessquare (#49363897) Attached to: Russia Wants To Work With NASA On a New Space Station

if you know your history, the area is ottoman, tatar, lithuanian, polish...

history can be used to justify any ignorant adventurist shit you can devise

what's actually important is the fucking borders of a fucking sovereign nation, and that modern states respect that

you didn't notice the imperial bullshit russia did on georgia in 2008?

russia is doing imperialism 1850 style. it needs to be, and will be, punished for being a stinking pile of destabilizing shit because of insecure nationalism. oh glorious russia has fallen from historical highs, boo hoo. and it will fall further now

Comment: Re:call it the Ukraine-2 (Score 1) 135

by circletimessquare (#49363323) Attached to: Russia Wants To Work With NASA On a New Space Station

they call ukraine "new russia"

http://en.wikipedia.org/wiki/N...

i suggest the usa call kamchatka "new alaska"

china can reclaim outer manchuria they lost to russia in the mid 1800s

http://en.wikipedia.org/wiki/O...

fuck you russia, imperial bullying douchebag

we should not be doing any space program with these assholes, we should be shutting down programs

Comment: Quote (Score 1) 135

by Rei (#49363093) Attached to: Russia Wants To Work With NASA On a New Space Station

"We are pleased Roscomos wants to continue full use of the International Space Station through 2024 -- a priority of ours -- and expressed interest in continuing international cooperation for human space exploration beyond that. The United States is planning to lead a human mission to Mars in the 2030s, and we have advanced that effort farther than at any point in NASA's history. We welcome international support for this ambitious undertaking.

Yeah, that's basically "Go F* yourselves" in diplomatic speech.

And as it should be.

He keeps differentiating, flying off on a tangent.

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