Wikipedia:Reference desk/Archives/Science/2012 August 9

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August 9

Curiosity landing site ?= Pambotis Lacus?

Somewhere between science and hallucination

The mountain that the Curiosity rover is to look at was called Mount Sharp (Mars) until it was renamed Aeolis Mons after a convention to name features after Classical albedo features on Mars. These date all the way back to Schiaparelli (1888). But I noticed that Schiaparelli has a map from the following year with extra details (above) which seems to place Gale Crater (a quite distinctive feature in the region) at the junction of the canals Antaeus, Cerberus, Cyclops, Eunostos, and Galaxias. (See List of Martian canals for text description) Looking these up I found [1] which describes this junction as "Pambotis Lacus" (Cerulli), saying it was "admirably seen by Brown and Molesworth". - except Galaxias is replaced with Pactolus. Of course, the canals are largely illusory, but not entirely - examining the visible map of Mars, one can readily see how several canals might be perceived in most of the directions observed, at low resolution, radiating out from the crater. I wonder if the low, dark region of Gale Crater is indeed this Pambotis Lacus? Wnt (talk) 03:41, 9 August 2012 (UTC)

And more crucially, will Curiosity find signs of a hidden Thern city there? Snow (talk) 10:48, 9 August 2012 (UTC)

I don't know about the Thern (is there actually literature set in Pambotis Lacus?) but I know the area is inhabited now - good show, NASA! Wnt (talk) 13:59, 9 August 2012 (UTC)

Therns are one of a number of fictional races which inhabit Mars in Edgar Rice Buroughs' Barsoom/John Carter of Mars novels, which, like most Mars-oriented sci-fi of the day, was highly influenced Schiaperelli's theory that the "canals" were an indication that Mars had once been a lush world cultivated by an advanced race but had since turned arid. Actually, in retrospect I seem to recall the Therns lived near the planet's north pole, so I guess Pambotis Lacus might be out of the question. :) But yes, the narrative does take place largely in cities established along these defunct canals, I think. In any event, I second your sentiment -- keep up the good work, NASA. On a side note, this particular mission keeps making my mind wander to Carl Sagan and how thrilled I have to assume he'd be Curiosity's mandate -- if only he could have lived to see it. Snow (talk) 18:30, 9 August 2012 (UTC)

Rocket vaporizing launcher pad/tower

Why doesn't the exhaust from a rocket launcher, like the Space Shuttle vaporize or at least damage the launch pad and tower? I don't know what the power of the exhaust is, but I'm assuming it's a lot. But after launch they seem completely unfazed as if the exhaust is completely harmless. ScienceApe (talk) 03:51, 9 August 2012 (UTC)

Launch pad and Mobile Launcher Platform have a bit of info. I thik the short answer is that the launch sites are specifically designed to deflect the majority of the blast and withstand or absorb whatever is left. Vespine (talk) 05:55, 9 August 2012 (UTC)

Lots of water is sprayed at the base, to contain the heat and baffle the energy being produced. Also, vaporizing paint it used, which burns off, but protects the metal underneath. Sensitive equipment has protective screens and covers, which close during takeoff. 217.158.236.14 (talk) 10:20, 9 August 2012 (UTC)

I wonder how safe it is for the crowd if the burnt paint fumes waft that way. StuRat (talk) 05:05, 10 August 2012 (UTC)

Or the hydrochloric acid vapors from the SSBs? DMacks (talk) 05:26, 10 August 2012 (UTC)

is olive a citrus fruit?

Could you please tell me if Olive can be considered a citrus fruit? A science textbook meant for high school mentions it as one. I am confused as I do not seem to find concrete information either supporting or denying it on the web. — Preceding unsigned comment added by Devakalpa (talk • contribs) 07:30, 9 August 2012 (UTC)

No it definitely is not. They are not even closely related at all. Olives belong to the family Oleaceae (which includes jasmines, lilacs, ash, and forsythias) in the order Lamiales. The genus Citrus and related plants, in contrast, belong to the rue family Rutaceae (which includes white sapote, clymenia, limeberries, and jaborandi) under the order Sapindales. They're about as closely related to each other as humans are to cows. The only thing they have in common is that both plant groups are extensively cultivated for oil extracts.-- OBSIDIAN†SOUL 08:03, 9 August 2012 (UTC)

Can flavor compounds and oils dissolve in saturated syrup if they won't dissolve in water?

I'm trying to decide whether I should go for extracts or syrups when making bubble tea, iced coffees and so forth. Syrups are mostly sugar, but is using a saturated sugar solution a strategy for dissolving moderately lipophilic substances? I know oil will dissolve sugar, so can concentrated sugar solution dissolve oils, esters, aldehydes, etc? (I know that "like dissolves like" but I know that for example, the emulsifier required for oil-in-water emulsions are quite different from water-in-oil emulsions).

Sugar has a lipophilic backbone, and sweetness receptors on our tongue require both a basic, acidic and lipophilic component (the property of all sweeteners), so I'm thinking the hydroxyls in a sugar syrup will be "locked up" by hydrogen bonding leaving oils free to interact with the hydrocarbon backbone. Syrups are also really viscous and have a high boiling point so a solution could be heated up to 300F to dissolve oils; if true solvation can't occur, I'm thinking that the syrup can break up oils into a tiny suspension at high heat. Sugar doesn't crash out when a hot saturated sugar solution is brought back to room temperature, so I am thinking the oils won't crash out either.

Also when I use the frying pan at high heat I notice it's often hard to distinguish the oil phase from the aqueous phase. Nothing gold can stay (talk) 17:15, 9 August 2012 (UTC)

I am revising the heading of this section from Can flavor compounds and oils dissolve in saturated syrup if they won't dissolve in water? to Flavor compounds and oils dissolving, in harmony with WP:TPOC, point 13 (Section headings). Please see Microcontent: Headlines and Subject Lines (Alertbox).

—Wavelength (talk) 17:37, 9 August 2012 (UTC)

Please don't change perfectly okay question titles without permission. Thanks! Nothing gold can stay (talk) 23:10, 9 August 2012 (UTC)

The solution, to avoid breaking links, is to "anchor" the original alphabet soup heading, as I have now done. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:35, 10 August 2012 (UTC)

Yes, but I would like to keep my original title. What's wrong with it? Nothing gold can stay (talk) 02:22, 10 August 2012 (UTC)

There is a real problem if you put links in your title, it diosrupts the archiving process. In this case yours was just a bit long and wavelength was trying to be economic, but I think consensus is that your title was okay. Much better than titles that are to short to convey the subject matter which is a more common problem. μηδείς (talk) 02:51, 10 August 2012 (UTC)

I have now anchored the other title, again to avoid breaking links. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:14, 10 August 2012 (UTC)

How would all of Earth's electronics get shut down (as depicted on Revolution (TV series)?)

On that TV show, one day, every bit of technology that uses an electrical current gets shut down. Planes fall out of the sky, pacemakers go kaput, cruise ships get stranded in the middle of oceans, and there's just pandemonium everywhere. News can't spread fast enough; the newspapers have to run manually, like they used to in the pre-electricity days.

And I would be in an epic panic because I don't think I've known life without electronics. I would like to know what to do ifever this happens.

1. But is there ANYTHING in existence that could permanently disable all electric and electronic devices on Earth within a 24-hour period?

2. Will there be anything that may be invented soon (how soon?) that could cause this?

3. But if nothing around today can, what are the devices that can come closest to causing such a disabling event, even down to draining everyday batteries?

4. Did some early automobiles run without the aid of a battery? What were they, and how would survivors recreate such vehicles?

5. After such an event, how would survivors re-invent the battery so that we could bring electronic devices back to working order again?

6. What would this mean for cruise ship passengers in the middle of an ocean? How would they get back to land without the help of GPS, et al.?

7. I'm a(n aspiring) tech junkie, and would like to know how to live without it. Can you show me a documentary of how a prolific, hard-core tech geek survived a time-period without modern technology (perhaps by homestaying with the Amish, etc.?) ^{(There are some documentaries out there where their subjects voluntarily go through a major temporary life-change that they would not have envisioned otherwise. I hope to find one that fits the above parameters.)}

8. Most importantly, does Wikipedia have a form of print media so that we can still look upon this resource for answers in such an apocalyptic time?

8a. Also, how would we keep an editing network together without the trappings of modern life? How would we submit edits and update the resource?

Thanks, you all. --70.179.170.114 (talk) 18:09, 9 August 2012 (UTC)

A Magnetar passing by Sol System would do the trick nicely. Hcobb (talk) 18:16, 9 August 2012 (UTC)

Keep in mind the show is pure fantasy and has no relationship with likely or even possible events. Electromagnetic pulses effect electronics, but not permanently; damaged components can be replaced. As far as I can tell, the show depicts something which effects some complex non-electronic devices as well. Cars and guns don't require electronics or batteries, but appear absent in this program. Modern cars, of course, are filled with electronics, but could be replaced with mechanical components that work reasonably well: crank starting would have to replace electric starters, carburetors would have to replace electronic fuel injection. --Daniel 18:27, 9 August 2012 (UTC)

Compression ignition engines (ie. diesels) don't require electricity to run. Spark ignition engines do. --Carnildo (talk) 23:33, 9 August 2012 (UTC)

Electromagnetic pulse (EMP) events could, if strong enough, do most of what's pictured in terms of the initial shutdown. You could get that sort of thing from a massive nuclear attack or from a freakishly large solar storm. As for the permanence, though, it doesn't stack up. Nothing about EMP would prevent you from building new power plants, new computers, new whatever, even if the old ones were rendered permanently useless. That's the core idea that really pushes this into fantasy, because it's basically altering the fundamental properties of the universe. For a sci-fi take on the sort of bootstrapping that would be involved in re-creating an industrial society, consider reading the novel 1632, which posits a ca. 2000 US town transported into the 30 Years' War (the book is freely available, per the link at the bottom of the article. For #6, large ships still carry sextants and have at least one officer trained in their use, and even basic seamanship will allow you to determine approximate compass bearings to allow dead reckoning. — Lomn 18:29, 9 August 2012 (UTC)

Considering that most modern machinery is built by computer-controlled robots, if all electronics were destroyed, including those in storage and radiation-hardend military-speced ones, it would be a slowish process. We would be put back into around 1920s level tech. We would then need to build hand lathes, and hand build motors and generators. From there, we can easily get to 1940s level, with valve technology. After that, we can start building machines to build better, finer-precision machines. Since we have (hopefully!) paper/microfiche blueprints of what we want to build, we know where to go, and how to get there. CS Miller (talk) 20:38, 9 August 2012 (UTC)

Maybe the electrons started running backwards? In all seriousness, as has been already illustrated above, it's not such an unreasonable idea that all (unshielded) electronics could be decimated -- though if it occurred during an event large enough to cause the blackout all at once it would probably be happening during an ecological disaster in which our lack of GPS and toaster ovens would be the least of our concerns. But, again as has been stated, this would not lead to a permanent state of affairs since the physical principles that govern electronic devices would not be changed and damaged components could easily be replaced (and indeed, certain developed nations have been moving towards protecting their most core information infrastructure from just such an event, since an EMP is seen as a (remotely) plausible form of terrorist attack and even solar activity could theoretically cause such a mass black-out. All of that said, I'm sure that the show will come up with some form of explanation for the enduring blackout and it will, just as assuredly, be absolutely trash science. Like most science fiction that makes it to network airwaves, I'm sure the premium will not be upon the science; rather the science will be technicalities to be minimally overcome or ignored to allow a hot woman to run around being a badass with her bow in a fantasy-like post-industrial setting. That narrative might still have potential for those who can suspend disbelief with regard to the science or don't know any better, but I'm not going to hold my breath. As to your other questions, automobiles could assuredly be made to work without batteries, but the starting process would be infinitely more volatile; cruise ships, depending on the degree of integration of electronics into actual engine and rudder control, could easily navigate using pre-electronic era nautical techniques; it's impossible to speculate how you could make a "new" form of battery without knowing what silly notion exists to explain why electricity is not working properly to begin with, but bear in mind that simple batteries may go back quite a ways; the net is rife with content on how to subsist without the aid of modern technology, but I don't know of one singular overview documentary (presumably cameras are anathema to the most hardcore proponents of this movement ;); Wikipedia has no print variation as its size and constantly changing nature make this prohibitive to say the least; and yes there are somewhat similar non-digital compilations of knowledge -- back in the dark ages we called them libraries. :) Not quite as interactive, of course, but they'd do under the circumstances. Hope that helps some. Snow (talk) 19:06, 9 August 2012 (UTC)

I am revising the heading of this section from How would all of Earth's electronics get shut down (as depicted on Revolution (TV series)?) to Earth's electronics shut down, in harmony with WP:TPOC, point 13 (Section headings). Please see Microcontent: Headlines and Subject Lines (Alertbox).

—Wavelength (talk) 18:42, 9 August 2012 (UTC)

I know of no previous occurrence of this discussion here, but as a general rule we tend allow, by unspoken consensus I think, for the wording of the title to be determined by the person making the inquiry since this is not, afterall, a talk page and the question is more the product of one individual's curiosity wheras talk pages involve convergent discussions on practical procedural matters (hence the reason for the point you cite, as explicitly stated therein). That being said, if the OP has no problem with the change then I don't but I think he should feel free to return it the original form if he likes. Also, I seem to recall that changing the title after a thread has been created her causes some sort of technical snaffu (something to do with the bot archiving? Someone help me out here, what am I half-remembering?), so it may need to be changed back for that reason as well. Snow (talk) 19:15, 9 August 2012 (UTC)

Lawyers. Definitely lawyers. They lobby up for Yet Another Patent Extension, and after that the Company (there can be only one) has intellectual property rights to the idea of electric power. They install military grade crypto copy protection metering and spy devices in everything with electric power, including mandatory safety devices embedded in each bullet. One day the CEO's kid inherits the mess, but the poor drunken sop can't remember the password. Wnt (talk) 19:23, 9 August 2012 (UTC)

And Edison's ghost beaming down proudly. On the patents, that is.Snow (talk) 19:38, 9 August 2012 (UTC)

You want The Waverlies by Frederic Brown. It is available on line. μηδείς (talk) 19:46, 9 August 2012 (UTC)

If memory serves, it's The Waveries. {The poster formerly known as 87.81.230.195} 84.21.143.150 (talk) 12:28, 10 August 2012 (UTC)

[2] Count Iblis (talk) 20:51, 9 August 2012 (UTC)

What a bunch of frelling dren. I thought the BBC was above such sensationalism. No known supermassive star threatens us with the proper axial alignment to bombard us with a gamma ray burst from close enough, and no stellar remnant has been found which can be associated with any such past mass extinction. μηδείς (talk) 22:05, 9 August 2012 (UTC)

My reaction as well. And the degree of certitude they attribute to the scientific community for some of these presumed "facts" makes it all the more laughable. And are they really proposing that virtually all life on earth has been obliterated by gamma-rays regularly every 100 million years of Earth's history? Apparently all the qualified fact-checkers at BBC's science desk were on vacation at once in May of 2002? On the other hand, I love the sci-fi possibilities of this scenario; Imagine, an entire eco-system consisting of Hulked-out organisms. Hulk monkeys, hulk insects, hulk hummingbirds.... Snow (talk) 22:41, 9 August 2012 (UTC)

If something neutralized electric current everywhere, wouldn't that also wipe out any organism that had a central nervous system? ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:53, 9 August 2012 (UTC)

Yup, or just about any organism relying upon excitable cells or action potential in any context. More so than this, if you can't expect electricity to operate as it must in the physical universe as we know it, who knows how membrane potential would work and whether any organism could exist. Of course, to assume that electrical current was universally disabled across the planet (without co-occurring with the destruction of any mechanism capable of generating such a current) we'd have to assume that basic physical laws were not in play in any event and thus all means of making sense of what was occurring, or even describing it understandable terminology, would be fruitless. It's like saying, "What if temperature increases didn't lead to thermal radiation?" The fact is they do and dependencies between this phenomena and all other physical laws mean that assuming such a hypothetical is silly because you then have throw out not only the dependent phenomena but also those which give rise to the defunct principle. Very quickly the whole house of cards comes crashing down and you're just spouting gibberish (which is one of the reasons why science-fiction of the sort which inspired this thread so frequently relies on techno-babble). Snow (talk) 23:16, 9 August 2012 (UTC)

How would all of Earth's electronics get shut down (arbitrary break)

You may also want to read Greg Bear's Blood Lines (novel) which gives a pseudo-quantuum mechanical explanation of how one could change the laws of physics to end the usefulness of electronic devices. Quite a good read. μηδείς (talk) 23:34, 9 August 2012 (UTC)

@ Bugs, a sufficiently strong electromagnetic pulse would burn out most unhardened electronic circuits within its line of sight in which a current could be induced. That would not harm cells, which overall are insulators, not conductors. Excitable cellular membranes work more like serial tripping capacitors than conductors. μηδείς (talk) 23:55, 9 August 2012 (UTC)

I took the meaning of Bugs' question to be inquiring about a persistent inhibiting effect like that suggested by the sci-fi scenario in question rather than a conventional EMP. However, bearing in mind the most likely source for an EMP capable of dealing large scale damage to infrastructure, we can assume there are concordant health risks (even be they directly unrelated to the pulse itself)! Snow (talk) 00:08, 10 August 2012 (UTC)

I suppose you could accomplish a lot with nanotech - some kind of ultra smart little robots with extraordinary mobility and communication, which can invade solid machines, sense out the power, and build bridges to tap it. (fire ants are a passable prototype) You'd need a pretty asymmetric scenario (lone evil genius, or more lawyers...) to explain why a similar nanotech network can't route around the bad nano to provide power to applications. Wnt (talk) 02:24, 10 August 2012 (UTC)

Anything powerful enough to suppress charge and current, would necessarily lead to the electrostatic dissolution of atomic matter. Read The Soft Weapon by Larry Niven.

As a separate matter the OP should be aware of, non-biologists often think nerves work like little wires. They don't. Rather, a local charge differential is maintained which, if depolarized, leads to the depolarization of the next "capacitor" down the line, transmitting a signal of tripping capacitors like falling (and self-righting) dominos in one direction down the length of a neuron. There is no lengthwise flow of electrons like water in a hose as with direct current. It is more a chain of local reactions triggering the next in line, like the watchtower beacon sequence in The Return of The King. See the action potential of neurons. μηδείς (talk) 02:46, 10 August 2012 (UTC)

And there's still more to the story for nerve cells than this membrane potential manipulation via ion pumps/gates; these cells also employ myelin as insulation along the axon, causing electrical impulses to "jump" across the insulated lengths and thus propagate forward more swiftly and potently. Snow (talk) 09:11, 10 August 2012 (UTC)

If we accept the premise that electric circuits are no longer possible (and add the usual sci-fi exception for anything inside a living organism), we pretty much have to give up on computers beyond an adding machine (IBM will have to go back to its roots). However, quite a few impressive bits of technology are still possible without electric circuits:

• Cars, as was mentioned, would need carburetors and crank starters. Lights would be another issue. Oil lamps or flares of some type would need to be used for headlights. Instead of blinkers, perhaps an arrow could point right, left, or up, depending on the direction you are going.

• Airplanes, similarly, would need a prop start (this doesn't necessarily mean a person has to do it, they could use a machine to crank it at the airport). Instead of wires, they would need to use hydraulics to control flaps, etc. Flights at night might be problematic, as lighting would create fumes that would need to be vented. Possible, but difficult.

• Rockets are theoretically possible, but would need a total redesign.

• Solar power would still be possible, but would have to work by focusing sunlight on a tank of liquid, which, when heated, could then drive a motor, provide pressure for a hydraulic or pneumatic line, etc. Hydroelectric, nuclear, or fossil fuel power plants could work this way, too, but a completely new power distribution system would be needed, using hydraulics, say, to deliver power to each house.

• For communications, we could use fiber optics, with a mechanical shutter system blocking and unblocking a light source, similar to old movie projectors, to send bits.

• For cooling, there are natural gas powered air conditioners. Heat pumps could also work off natural gas, hydraulic pressure, etc. StuRat (talk) 04:46, 10 August 2012 (UTC)

Sorry Stu, but both your communication and power grid notions are untenable. You could heat a cistern with sunlight, sure, but the amount of energy you could "focus" into it would be limited; you'd need a massive array of lenses just to get a relatively small amount of water to heat to boiling point to drive a small motor. Hydroelectric methods are by definition exclusive to the situation we are talking about here. Nuclear power cannot be feasibly maintained without a complex electrical regulation system. Fossil fuels would be your best bet for generating the energy, but here's the catch - generating it (be it by any of the above methods) is actually the "easy" the part. Delivering it via hydraulic pressure involves such massive inefficiencies and energy-loss ratios that you couldn't transport that energy very far and there would be no way to store it, so the regulation of the system for getting energy where and when it's needed would be prohibitively complex without the aid of calculating machines (and no, pressure-powered mechanical variants would not be up to the task, I'll get to that briefly). Best case scenario, a few highly intelligent people who were willing to devote the majority of their lives to maintaining and regulating their systems (and had exceptional aid and resources in this new stone age) could use fossil-fuel driven motors (and let's not forget the new difficulties arising in harvesting those in these circumstances) in order to power a few simple mechanical devices in their homes, with each such device requiring fine calibration and constant oversight to operate and tap into that mechanical energy.

The fiber optics proposal is even more dubious. First off, the maximum speed you'd be able to achieve for data transfer with a mechanical shutter system would make it about as fast as sending bits by smoke signal (probably slower, in fact, factoring in distance). That's assuming it wouldn't require tedious manual operation that would be subject to considerable error, which of course it would. Then there's the matter of how you're going to generate the consistent light of uniform intensity without electricity. Or how you're going to continue to manufacture cable without impurities (or period, given the complexities involved in the process) without the benefit of modern technology. But let's say you overcome these issues (given all of the other implausible occurrences we've been assuming from the start, we can suggest aliens are supplying you with materials and beaming down columns of pure white light and you've trained tiny microbes to translate your intended messages into binary and operate the shutters at intense speeds because, why the hell not at this point?). Where are you sending that data to? I know you already conceded this point, but it bears repeating that you don't have computers in this scenario. You could try to create mechanical equivalents (there was some experimentation along these lines prior to the advent of electrical transmission), but they would need to prohibitively gargantuan, complex, and prone to failures which would take devoted experts working around the clock to resolve just to perform anything approaching what we'd consider simple operations today. A machine with the processing power of a TI-82 would be the size of a house (and not a small one) and even then would work at a fraction of the speed, all while requiring a team of engineering geniuses to maintain, operate, and modify for different uses, if you could find and keep such people in one place for such limited gain in this new and probably quite chaotic world. And without such devices your fiber-optic system, if it were viable (which it wouldn't really be) would be at best a less reliable version of a telegram.

So, yeah sorry but the simple fact is that the digital world, for all practical intents and purposes would end with electricity. As would any practical hope of an energy grid. And those few rudimentary tools you could create and maintain would never return to you a fraction of the energy or practical use that went into developing the materials and components involved. All of your other propositions besides those two are viable, of course; and in fact they all have been employed at one time or another in formats that do not require electricity. And I grant you the rocket-powered airships would be baddass. ;) Snow (talk) 06:36, 10 August 2012 (UTC)

Mechanical shutters can be pretty darned quick. Before the electronic TV was developed in the US, the British had developed a mechanical wheel TV system. That's got to mask and unmask a lot of bits per second. I'd expect it to be used to send signals like a telegraph or text message. I don't think creating a uniform, bright light is much of a problem. Lighthouses managed to do so before electricity.

Nuclear power is still possible, but it would be more like the simple systems for space ships, not the complex systems we use in nuclear power plants today. That is, we would have many small reactors generating power for just a few homes. This model would work for other types of plants, too. There might be a power plant on every block. In the early days of electricity, before A/C, this was how it was done, using D/C.

Solar power wouldn't use lenses, it would use reflectors. There are already solar plants that use this method: [3]. You don't necessarily need to boil water, if the goal is to heat a building, you can just pipe the hot water into it. (You could also use a fluid with a lower boiling point than water, but then you'd also need to recondense it, rather than just vent the steam.) StuRat (talk) 09:18, 10 August 2012 (UTC)

It's not just a matter of how fast the shutters can open and close (though even the fastest shutters in the world are thousands to hundreds of thousands of times slower than the transfer rate of bits over even a limited network connection); a mechanical shutter is never going to approach the bitrate of even antiquated electrical systems simply because of physical limitations, but even if we ignore these physical principles and assume the shutter could move faster than in reality it could, it doesn't really matter since there would still be limiting factor of the encoding; the shutter wouldn't just be opening and closing at it's maximal rate constantly; it needs to be open and closed in specific sequences or else it's not transmitting any information. And since there is no computer handling this process in this scenario, this means that each and every bit of data needs to be sent manually (and then re-interpreted by sight on the other end). And creating the appropriate light is more complex than just having a bright source; fiber optic cables require light of a very specific intensity and spectrum which is easy enough to generate if you have an electrically generated light source attached to a digital transmitter but impossible to regulate reliably without. Lighthouses don't need any such refinement, they require only the brightest light source within the human visual spectrum reasonably available to announce their presence. Could you create something like a crude telegraph that operated over very small distances? Yeah, but it wouldn't be of much use as a communication network.

Initiating and maintaining controlled nuclear fission in a reactor would be utterly unfeasible without an electrical system, period. And it and any other plant would be subject to the limitations and efficiency issues noted in detail in my previous post, even over short distances; the amount of energy you got out of it in the form of useful mechanical work would be miniscule compared to that put into it and would require more fuel than you could possibly acquire for it. Even if we stipulate said resources, there's still the matter of regulating the flow of hydraulic pressure when and where it is needed; this could not be automated and the amount of work needed to regulate it would again dwarf any practical benefit (this is not so much an issue if you assume perhaps that hundreds of people are working for the benefit of one person to have a few amenities, but for creating an actual grid, it's unfeasible). Anyway, where's this energy going in any account? Only the smallest fraction of known human devices can operate usefully with mechanical or thermal energy alone, so if you want to warm a bath, it's fine, maybe even crank a phonograph (that's just one example of a simple device that would nonetheless have a complex integration into the system, though), but anything that absolutely required electricity previously (that is, virtually all modern human technology) is out of the question.

As for solar power, whether you use lenses or mirrors (which are not all that distinct in this context, really, as regards the function they are providing) is a non-issue. The system referenced in the link you provided still converts the energy in question into electricity, it simply uses a parabolic reflector to concentrate the light on to a receiver rather than using a photovoltaic cell. This is nothing new, similar facilities have been place for years throughout the world, but they still involve electrical current (in fact, this is a major issue for solar power, since you can't store this energy for when the sun is down, without a thermal medium, but for our purposes here this would just translate to still more energy loss). And sure, you could use the system for temperature regulation immediately on site, but that's not really the context that was being discussed. And even in that scenario you are again talking about massively more work than the benefit justifies, especially when you consider that transporting adequate water in this new post-industrial context is going to be a chore, and manufacturing the appropriate materials (parabolic lenses, for example) for every house (or even a small fraction of them) would be next to impossible and the efficiency of any such system is going to be low; these facts being why solar energy and water were never combined for much practical purpose previous to the electrical era. What it all boils down to (get it, get it? :) is that you simply aren't going to end up with grids or technology significantly more complex than what existed immediately previous to the industrial age (say, Edwardian England, for example); our advancements in understanding of material science will only carry you so far without the existence of electricity. Snow (talk) 11:33, 10 August 2012 (UTC)

I don't think you read the entire link: "As in a conventional power plant, this thermal energy can then be converted into electricity via steam- or gas-powered turbines, or it can also be used for other industrial processes such as water desalination, cooling or, in the near future, the production of hydrogen". Placing a factory near such a plant would allow you to use the energy without the distribution losses. As for power distribution, steam tunnels are still in use today in many cities, while hydraulics and pneumatics were also more widely used prior to electricity (there was even a pneumatic subway). Distributing water without electricity just requires a gravity fed system; we have many around the world now (and have had since at least Roman times). As for limited distances with a fiber optic telegraph, you could always have each operator resend the message along the next link, as was done with the early telegraph. StuRat (talk) 20:01, 10 August 2012 (UTC)

Yes, gravity fed systems have been around since Roman times -- doing the kinds of things Romans did with them, not recreating a modern power grid and technology. They are infeasible for this purpose as per discussion above. You're going to have to provide more context for which shortfalls you expect steam tunnels and pneumatics to make up for, but even before that I can safely make the blanket statement that, as with any purely mechanical system, their usefulness in recreating what would be lost with electricity is going to be very limited. As to your fiber-optic relay system, I have to ask, why would you do it this way? If you're just going to use an optical system where the major limiting factor is going to be the relay points themselves, why go to the trouble of finding and burying the wire and overcoming the (probably impossible to overcome) barriers with transmitting along it when you could just use an above-ground system of semaphore? It would be just as fast (though probably not fast enough to justify the effort over say, a letter on horseback). Well, maybe you have to keep your messages secure, because at this point if you're attempting any of this and have even the smallest fraction of the resources necessary to gain some traction, you are clearly a mad tyrant working the surviving human population to death to produce a few crude reproductions of previous technology! Snow (talk) 22:21, 10 August 2012 (UTC)

I will continue to protest that once you introduce one contradiction, you have introduced every contradiction. A circuit-shorting grey goo will either kill us all or go extinct once its foodsource is dead. That being said, StuRat's suggestions are very steampunk sexy. μηδείς (talk) 05:06, 10 August 2012 (UTC)

I doubt it. I don't know what the bastards working on smart dust have managed to accomplish, but I bet it lasts a lot longer than I want. Like any bacterium, the nanotech could "sporulate" and come out at intervals after a long period of wind dispersal. And if it's specifically designed to feed on large (>1 V) differences of electrical potential, and to use a range of reduced metals as its source of raw materials, it's hardly "grey goo". Wnt (talk) 13:09, 10 August 2012 (UTC)

Medeis is onto it like I am. I was going to ask, Sturat, do you suggest that the post-electricity cataclysm marks the beginning of the Steampunk era? If an electricity-disabling event were to ever happen in real life, please be the Steampunk's Thomas Edison, okay?

PS: How would we get phones, and mobile phones, remade through these methods? --70.179.170.114 (talk) 05:25, 10 August 2012 (UTC)

Quite simply, you wouldn't. By definition these devices work through electromagnetic mediums. This is the only telephone you'd be using. Though again, and I can't belabour this point enough, the idea of electricity not "working" (in any context that would not have already vaporized all life on the planet) makes no sense and never will. Snow (talk) 12:08, 10 August 2012 (UTC)

Land-line phones might be possible using the fiber optics system I described, and a method of translating sounds into either analog or digital optical signals. I even wonder if such systems might currently be a viable alternative to EMP-shielded electrical phones in critical locations. I think we'd be SOL on cell phones, though. StuRat (talk) 09:23, 10 August 2012 (UTC)

Ok, this is the point where I have to call nonsense. How would you translate optically-encoded patterns into acoustic waves without electricity? Snow (talk) 12:14, 10 August 2012 (UTC)

Lasers would be the new "Plastics". (Don't ask me how you would excite the crystals without electronics; line of sight would be a bitch.) But invest in lasers young man. μηδείς (talk) 05:41, 10 August 2012 (UTC)

Oh, duh. Match-lit atom bombs, x-ray lasers, mirrors and Fiber optics. μηδείς (talk) 05:43, 10 August 2012 (UTC)

• Just because we can't think of something in a minute doesn't mean it isn't possible. Phenomena like superfluidity and second sound allow extremely rapid transmission of information without electricity. Light exerts pressure, stimulates chemical reactions - no reason why it can't be converted directly to sound, if someone thinks of a way. I'm going with the trained cicadas :) Any hypothetical ban on electricity, which somehow distinguishes between interfering with the conduction band of metals (and semiconductors?) and interfering with other types of excited states, leaves the possibility of using those other excited states in some ways that electricity is used now. Phonons, nuclear isomers, even some upgraded version of the tin can telephone that contains ultrasound to use as a power source (as has been proposed for refrigeration). The possibilities are endless. Our culture has not sampled every method of doing things, only the ones that were cheapest at the time. Wnt (talk) 13:23, 10 August 2012 (UTC)

Sorry, but such vague speculation doesn't cut it. We may not have created every form of technology feasible that is consistent with the physical laws of the universe as we know them, but we can make certain deductions on what is possible based on those same principles, and even further, what would be feasible under those circumstances from amongst what is possible. This is the science desk, not the science fiction desk; if he's going to make such a proposal he should be able to describe, at least in the most nebulous fashion, the mechanism that would be at work. No such mechanism exists, lacking electricity as an intermediary medium; I'll eat my hat if someone can prove otherwise. Just because a photon can catalyze a chemical reaction doesn't suddenly turn it into the Philosopher's Stone, capable of transmuting the fundamental nature of matter around it. Your joking scenario with the cicadas will come true sooner than Stu's proposed phone. The light coming over the fiber optic line would be simple binary; how is that being translated into sound waves of varying intensity and frequency at the other end via a chemical process alone? That's before considering the through-put limitations of a mechanical transmission system. So let's say you have a thousand such cables running each way (for each phones receiver and transmitter; creating/harvesting uniform cables to do this work in a post-electrical era would be next to impossible, by the way --it's not like you can just cut and splice them together to fit your needs -- but let's ignore that for now). Let's also say you've overcome the problems with creating a high intensity beam of light discussed above (almost certainly not possible without electricity, but moving on...). You've got these beams aligned and calibrated (with precision you could never achieve without modern electrical technology, mind you) to each cable. Each individual cable has its own shutter and is set up to receive the intensity data for a given frequency (there's no way the mechanical shutter would be fast enough, but let's assume you're willing to accept a significantly downgraded, almost unintelligible quality of sound). So now the moment of truth - how do you isolate all of the frequencies of a voice (or other audible sound) such that each impacts upon a different mechanism and somehow causes a chemical reaction which is somehow changed into mechanical force, but not just an force, but a force somehow starting and stopping in the exact sequence necessary to operate the shutter in a fashion to transmit the code (this is probably the most nonsensical part of the whole equation, which is saying something). At the other end, the light has to somehow catalyze a reaction or otherwise transfer into a mechanical wave which then somehow has to be re-translated into an acoustic wave (and where is the energy for that process coming from and how is it being integrated into to this temperamental system?) and each of these waves has to then somehow be recombined to reproduce the original sound. Please note that with regard to most of the "somehows" italicized above I am not just marking an unresolved detail but in fact something that is almost certainly physically impossible to achieve lacking electrical facilitation of some sort. And I've barely scratched the surface of limiting factors here. Non-electrical light phones = utter nonsense. Even if it were, can you imagine the scale of the thing and the undertaking it would constitute?. It would take lifetimes to create, massive efforts to maintain (if using chemical reactions, those chemicals would have to be created and carefully calibrated for each brief exchange), just so you can send a muddy phone message a twelfth of a kilometer every now and again? When vastly more efficient forms of distance communication would be possible? -- Optic semaphore has been suggested bellow and seems the obvious choice to me. And this is all for one pair of receiver/transmitters. How could you ever create this (already impossible) device over and over to create mass communication? Sorry guys, but the possibilities are not endless here, just apparently the speculation. :) Snow (talk) 21:46, 10 August 2012 (UTC)

Alright, here goes. You hook your microphone to a phonograph needle, which by a sensitive mechanical linkage opens a variable shutter (not digital, analog) to a powerful ultraviolet light which is always on. The light passes through the fiber optic cable to the far end, where it strikes a tape coated with photoresist. This is then etched by acid as it passes through rollers, leaving a track which goes up and down like a classic phonograph record. This is then played by a traditional gramaphone. Now true, this set-up is expensive, imposes a long time delay, and probably would have atrocious sound quality. But, I think it's fair to say it's possible. And in a society that needed to do something like this, it would be steadily upgraded, perhaps until these problems were actually dealt with rather effectively. Wnt (talk) 02:38, 11 August 2012 (UTC)

one or more fiber optics bringing through UV light

• If electronics was somehow made unworkable we could still transmit power for a mile or so from a point of a prime mover, and could still communicate over distances of a mile or two by acoustic telephone and transcontinentally by optic semaphore. A substantial amount of late 19th century non electric power transmission was done by pipes carrying water under pressure (hydraulic) by drivebelts on overhead poles and by compressed air. Some time ago I posted a link to an 1880's study giving details of the efficiency and cost of several of these nonelectric power transmission systems compared to electricity, and as I recall some were competitive over distances of less than a mile. Nathan Stubblefield patented an improved acoustic telephone system (US 378.183) in 1888 which was used commercially for distances of a mile or so. A "switchboard" would have to be devised. Pulleys were used to make turns. Speaking tubes work nicely for hundreds of feet. Bellpulls work nicely withing buildings or between nearby building for communication. Pneumatic tubes were used in the 19th century to send mail and documents for a mile or two in central business districts. Semaphore relay towers could send message over long distances day or night in the absence of fog or dust storms. Diesel engines could run without electricity, but even a gasoline powered car with a starter crank needs spark from the spark plug to run. Edison (talk) 18:44, 10 August 2012 (UTC)

According to the article Stubblefield's radio was electrical in nature. It says it wasn't a "true" radio because it used 'near field' or 'ground conduction' - but over distances of half a mile to a mile??? I still don't understand, but it wasn't acoustic. Wnt (talk) 21:10, 10 August 2012 (UTC)

Yes, his radio was electric, but he also invented and sold an improved acoustic-mechanical-nonelectric telephone. It would be a nice part of a steampunk world. Edison (talk) 05:23, 12 August 2012 (UTC)

I would just like to point out that in the petrochemical industry where intrinsic safety is of critical importance, there is a wide array of non-electrical systems that are suprisingly high tech. I wouldn't underestimate what technologies are possible even without electricity. 112.215.36.182 (talk) 06:18, 11 August 2012 (UTC)

Looking up mechanical amplifier gives a vague indication of preelectronic amplifiers existing, though I don't understand the explanation. It also reminded me of fluidics, a sadly incomplete article which still points out that such devices exist, and may indeed ultimately be of real world relevance to logic circuitry. Now if you can have a string of very good, truly linear mechanical amplifiers that don't add distortion, and if you can design a cable or other medium without "chromatic aberration", so that sound of all frequencies travels at exactly the same speed (not sure what you call that), then you can actually have a tin can telephone that spans continents. In theory, anyway... Like our modern phone network, it would take a lot of painstaking research and optimization. Wnt (talk) 20:11, 12 August 2012 (UTC)

Preservation of Wikipedia in such circumstances

WP:TERMINAL is interesting, despite being intentionally humorous. Double sharp (talk) 09:30, 12 August 2012 (UTC)

Actually, Wikipedia would fall apart, I believe. The whole premise is that you can add stuff and make it universally available and it doesn't cost much. If communications networks are long term impaired, so that the cost of physically printing and messaging data is once again rate limiting, then once again you return to the archaic situation in which copyrights seem workable - a small, practicable tax to reward authors rather than making the difference between buying access to 100 books a year or 10 billion books a year. Wnt (talk) 20:16, 12 August 2012 (UTC)

At least Wikipedia's featured articles (from 2010) would be preserved: [4]. And Books LLC and VDM Publishing are trying to print as much of Wikipedia as possible - maybe it is actually for a noble cause! Warofdreams talk 15:49, 13 August 2012 (UTC)

Earth-Moon orbit

The Apollo missions were initially on free-return orbits to the Moon - they would do a figure-8 around the Moon and come back to Earth. Is the point that the orbit passes directly between the Earth and Moon (and crosses itself) at the L1 Lagrange point? Bubba73 ^{You talkin' to me?} 20:27, 9 August 2012 (UTC)

This sounds like a homework problem! Apollo By The Numbers, available for free online from NASA, gives precise details for all the orbital elements for each mission. Particularly, look at Earth Orbit data and Trans-Lunar Injection. If you solve the equations of motion (Buzz Aldrin wrote up a paper on exact iterative solutions to Kepler's laws, which should be "good enough"), you can forward-project the actual orbits following the TLI burn, and see if the trajectory would be anywhere near the L1 when it crosses the Earth-Moon radial line. If you accurately account for each orbital correction maneuver, you'll end up with some very non-Keplerian orbits, so I doubt if the L1 point and the radial-line crossing-point coincide - and even if they do, it probably has little analytic importance! Nimur (talk) 00:32, 10 August 2012 (UTC)

I think I can safely say that Bubba73 has long since graduated. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:31, 10 August 2012 (UTC)

Okay, put it another way: start with the L1 point. Vary the angular momentum. Calculate the lines of constant energy. If any line circumscribes both Earth and Moon, that is a Earth-Lunar free-orbit trajectory that intersects the L1 point. Nimur (talk) 01:27, 10 August 2012 (UTC)

I was thinking of an idealized orbit without rocket burns. Bubba73 ^{You talkin' to me?} 01:32, 10 August 2012 (UTC)

Yes, which is why my second suggestion was to draw out lines of constant energy, for the initial condition at the L1 point, with angular momentum as free variable. Nimur (talk) 01:48, 10 August 2012 (UTC)

I last took physics 34 years ago... Bubba73 ^{You talkin' to me?} 03:05, 10 August 2012 (UTC)

You don't need to take physics in order to understand orbital mechanics. You just need to do physics. Sometimes it helps to have a classroom setting to formalize the mathematical techniques, but that's hardly a requisite.

Conserve energy, and conserve angular momentum, and you can solve any orbital mechanics problem. There are a few coordinate substitution tricks that help deal with a rotating reference frame, but none of those are necessary to find a valid solution. My favorite method is to construct an effective potential energy field that includes the effect of angular momentum: then your object simply trades total effective potential energy for total kinetic energy, and you can easily visualize the orbital path (in the rotating reference frame). Nimur (talk) 05:50, 10 August 2012 (UTC)

I thought both of those things could be violated (unless you count the planet and moon), as in the gravitational slingshot? Wnt (talk) 15:27, 10 August 2012 (UTC)

Judging from the path shown here: http://www.braeunig.us/apollo/free-return.htm and from the value of 321.689 km (http://esamultimedia.esa.int/docs/edu/HerschelPlanck/EN_13e_L_Points_EarthMoonSystem.pdf ), I don't think it's the point where the path crosses itself. Ssscienccce (talk) 01:53, 10 August 2012 (UTC)

That is extremely interesting - I printed it out and made some measurements. It is close, but not on it. The equigravisphere is 346,089 km from the center of the Earth (0.90033 of the way to the Moon). I measured the crossover at about 350,500-353,000km from the center of the Earth. (But when the object is at the equigravisphere point, the Moon is not yet where the object loops around it, so it may be equigravipshere from where the Moon is at that point, which will through this off.) Bubba73 ^{You talkin' to me?} 03:05, 10 August 2012 (UTC)

But the equigravisphere seems to be an arbitrary definition used by NASA mission control as the point where they change reference frame, switching to distance and velocity relative to the moon instead of the earth (and confusing the journalists with the change in speed of Apollo 8). My number of 321.689 km was wrong I notice btw, it's not the distance to the center of the earth but to the center of mass from the earth + moon system. Ssscienccce (talk) 04:50, 10 August 2012 (UTC)

Note, the L1 point is not the same as the point where the gravity from the Earth and Moon are equal. L1 is in Earth orbit, so you need some gravity left to provide the centripetal force to maintain that orbit. --Tango (talk) 11:22, 10 August 2012 (UTC)

And we have seen the image of the spacecraft making a figure-8 around the Earth and Moon so often that it is easy to forget that the Moon is moving (at least for me). There is no point when the spacecraft is directly between the Earth and Moon, much less where they are pulling on it equally in opposite directions. Bubba73 ^{You talkin' to me?} 14:38, 10 August 2012 (UTC)

Resolved

Bubba73 ^{You talkin' to me?} 01:40, 14 August 2012 (UTC)