Wikipedia:Reference desk/Archives/Science/2014 June 9

Science desk
< June 8	<< May | June | Jul >>	June 10 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

June 9

Garden water hose

I need to water my flowers outside the house. First I purchased a conventional long hose and tried to use it. It is really a pain in the neck. It kinked all the time and using it became a nightmare. Then you have to put it back on that ceramic pot which is another exercise in futility. I spend more time straightening it out than actually watering my flowers.

I then went to the home depot and found a solution. They sell curled hoses. They look like a thread on a bolt but only very long. It is an order of magnitude easier to work with them. It also curl in kinks but not that much and every time it is easier to separate portions (straighten them out).

Can it be described in clear mechanical terms why the pre-curled hose worked better than straight one?

Thanks, - --AboutFace 22 (talk) 01:37, 9 June 2014 (UTC)

Not quite sure what you mean by a "pre-curled hose", but here's some advice on conventional hoses:

1) Get short lengths and daisy-chain them together. This makes each length easier to manage. I find I can wind up 25 feet of hose easily on my arm, and 50 feet with great difficulty. More than that would be impossible. Also, if one segment starts to leak, you just replace that segment.

2) With each wind, I turn around. This counters the twist that builds up otherwise. I can skip this step near the end, when the hose is free to rotate.

3) Get an anti-kink hose. You can tell in the store if it already has kinks in it, that it's junk.

There's also those new inflatable hoses, like Xhose. They have some advantages, like having less of a problem with kinking and being lighter and smaller when dry. However, they tend to leak, water keeps pouring out for a minute after the faucet is turned off, and they don't fully dry out, and thus fully collapse, for a very long time. I'm also not sure how long they will last. StuRat (talk) 02:08, 9 June 2014 (UTC)

Thanks, StuRat. The hoses you describe, the ones they advertise on TV which so well work on the screen have in fact extremely bed reviews. The are available on Amazon and everything I read about them indicated they should be avoided and of course, the major problem is leekage. --AboutFace 22 (talk) 02:21, 9 June 2014 (UTC)

LOL, little leeks grow around them ? I have such a hose myself. Yes, it leaks, but that's OK for some applications, like watering the lawn. The leaking all seems to be around the connection to the faucet, and they have a new, more expensive version "with brass fittings", instead of plastic. Those might fix the problem. StuRat (talk) 02:38, 9 June 2014 (UTC)

Regarding the "pre-curled hose", I suspect it's like a slinky. Most of the extension and other types of motion are comparable to stretching it as a spring, which seems like it would distribute any bending along a larger length (or at multiple locations) compared to bending a straight hose. A kink instead is a large amount of bend (or change in amount of bend...the next derivative) in a small area. DMacks (talk) 03:24, 9 June 2014 (UTC)

Another trick that works well with a long normal garden hose is to wind it on the ground into a figure-of-eight (say 2 metres in length) or over two pegs on the wall from an untwisted state. The on-the-ground version can be folded in two for carrying and storage. The advantage is that winding and unwinding is pretty quick, with no twists to compensate for once you get the knack of it. A degree of anti-kink in the hose helps, but is not essential if you're careful. —Quondum 04:05, 9 June 2014 (UTC)

Exactly - the reason that winding a standard hose causes problems is because the inside radius of the curve is slightly less than the outside. A hose can't be stretched, so instead it twists to compensate for the uneven lengths. There is a limit to how much it can twist, and it leads to it getting harder and harder to wind each loop until it kinks or just won't stay wound. A pre-coiled hose will wind back up easily because that is the shape it was made in, but you have similar problems stretching it to full length. A figure-eight winding pattern makes the hose curl in opposite directions every turn so everything balances out and it winds easily. Also, don't ignore the quality of the hose - in my experience the cheaper ones tend to kink very easily compared to higher-quality ones. Katie R (talk) 11:51, 9 June 2014 (UTC)

Yep - I coil long power cords the same way. When you wind anything like that onto a cylinder, by facing the end of the cylinder and moving the hose in a circular fashion as you add it to the coil - each loop around the cylinder adds one rotation of twist to the entire length of the hose. Ideally you either need a hose reel with a handle on it so that you wind the reel itself, pulling the hose onto it - or you do as I (and Quondum) do and wind your hose into a figure-8. Each loop then consists of a clockwise and an anticlockwise twist - and as you pull the cable/hose away, those two twists cancel out. I can't imagine why hose and extension-cord makers don't provide figure-8 holders - but a hose reel with a handle on it is a good alternative. SteveBaker (talk) 14:30, 9 June 2014 (UTC)

The relevant concepts to coiling cords/hoses are at twist and writhe. Basically, one gets converted to the other as you coil/uncoil: you can't coil successfully without also adding compensatory twist. To all those who have problems coiling their hoses, I suggest they at 1/2 twist for each 1/2 writhe. It takes a bit of practice, but doing it the right way makes it much easier in the long run. SemanticMantis (talk) 16:16, 9 June 2014 (UTC)

Adding/subtracting 1/2 twist to the entire length of 100 feet of hose as you coil/uncoil it isn't easy! Winding in a figure 8 pattern completely solves the problem because the 1/2 twist in one loop of the '8' is counteracted by the -1/2 twist in the next loop. Over the total length of the hose, both writhe and twist sum to zero - so you never have to perform any rotation on the entire hose.

The other way is to note that writhe and twist only interact when they are rotations about non-orthogonal axes. By winding the hose onto a drum, you arrange that the writhe is at 90 degrees to the twist axis and they don't interact at all. SteveBaker (talk) 18:58, 12 June 2014 (UTC)

Thank you guys, it is a wealth of information. --AboutFace 22 (talk) 02:50, 10 June 2014 (UTC)

Hydrated hydrogen ???

I am currently reading a book by Raymond Lamont-Brown "Kamikaze" which is naturally about the history of that WWII madness in Japan. I want to give a brief personal impression of the author, I think he is a serious Oriental linguist with vast amount of knowledge on the subject. The book is peppered with Japanese expression and their translations into English. At one point he describes the internals of one of their weapons, suicide rocket Ohka. I quote "The Ohka rocket was a Rogo-type wherein condensed hydrogen peroxide reacted with hydrated hydrogen,..." This phrase appears on page 97.

I see two problems here. Hydrogen peroxide is a liquid under normal temperature (although volatile) and there is no need to condense a liquid. Number two: what is hydrated hydrogen?

Thanks, - --AboutFace 22 (talk) 01:57, 9 June 2014 (UTC)

The "condensed" part is probably just a mistranslation of "liquid". StuRat (talk) 02:12, 9 June 2014 (UTC)

It is a book written in English. What kind of translation do you have in mind? --AboutFace 22 (talk) 02:16, 9 June 2014 (UTC)

"Japanese expression and their translations into English". StuRat (talk) 02:17, 9 June 2014 (UTC)

It certainly sounds like things got a little distorted. The operational Ohka was apparently propelled by solid-fuel rockets, with trainer variants that sound as though they used air as the source of the oxidizing agent. "Hydrated hydrogen" does not make sense, and the closest thing that I can think of, hydrated hydronium, would definitely not fit the bill. —Quondum 03:55, 9 June 2014 (UTC)

According to a handy page called The History of Hydrogen Peroxide Propulsion, a mixture of hydrazine hydrate, methanol and hydrogen peroxide was used by the Germans in WWII. So your quote might mean "The Ohka rocket was a Rogo-type wherein concentrated hydrogen peroxide reacted with hydrazine hydrate,...". --Heron (talk) 18:13, 9 June 2014 (UTC)

Thank you. I also felt that hydrated hydrogen did not make sense. --AboutFace 22 (talk) 02:52, 10 June 2014 (UTC)

I think that Heron has the right answer, but I will draw your attention to hydrogen clathrate, which is another kind of hydrated hydrogen. Graeme Bartlett (talk) 21:44, 10 June 2014 (UTC)

Cosmos fact checking

The finale of the new Cosmos series aired tonight. It contained some facts I'd like to ask about:

1) "Some cosmic rays have as much energy as a bullet fired from a gun." I see some discussion of this at ultra-high-energy cosmic ray, but how can they carry that much energy ? Are those ones made of anti-matter ? Or are they far more massive than normal subatomic particles ?

2) "The gold record on Voyager 1 (or was it Voyager 2 ?) is expected to last for a billion years." Note that the spaceship is now outside the heliopause, and hence is exposed to even more radiation.

These two facts also seem to be in conflict. That is, after a few million years, won't these cosmic rays damage the record ? StuRat (talk) 02:34, 9 June 2014 (UTC)

"Cosmic ray" usually refers to a photon, not to an ion or neutral massive particle (i.e., neither matter nor antimatter). But, a plausible source of cosmic gamma ray flashes, including those that could contain such highly energetic photons, are matter-antimatter annihilation reactions. It is very unlikely that an individual photon would carry as much energy as a bullet fired from a gun; but to quote Douglas Adams, "space is big, I mean really big." In other words, very unlikely phenomena can still occur.

A good friend of mine believes that very energetic gamma rays may be caused by lightning strikes here inside Earth's atmosphere. While I respectfully disagree with his opinion (at least - in writing... to his face, I disagree with very little respect), I have to concede that he has published a few articles in peer-reviewed journals, including those that our article cites, so I guess that means scientific consensus is on his side. Because our spaceborne cosmic gamma ray observatories - like Compton Gamma Ray Observatory - are very poorly directional, it is plausible that they are detecting high-energy photons from earthly sources, like lightning strikes or covert nuclear test detonations - but those are also pretty unlikely.

Whether any such rays will damage the golden record really just becomes a game of statistics, with absolutely immense uncertainties. How likely are encounters with energetic particles or high-energy photons in interstellar space? How will these probabilities vary over the next billion years? Well, to answer that quantitatively, we'd need to launch a space probe to collect some data... Nimur (talk) 03:21, 9 June 2014 (UTC)

The extremely energetic cosmic rays are postulated to be massive particles such as protons, not photons, if you read the Cosmic ray, Ultra-high-energy cosmic ray and Oh-My-God particle articles. High-energy gamma rays apparently are not called cosmic rays at all. Photons would need to get their energy from a single emission event, which would require even higher particle energies, whereas charged subatomic particles can be progressively accelerated to high energies given the right conditions. Explaining quite such high energies is nevertheless a challenge, and the microwave background radiation would sap their energy, reducing the volume of space from which they could originate. To answer the first question, they are probably mostly normal charged subatomic particles such as protons and electrons, and they may gain their energy by acceleration in naturally occurring linear accelerators, for example in the shock wave of a supernova explosion. —Quondum 03:34, 9 June 2014 (UTC)

I suppose we have a few orthogonal variants of terminology. It seems some sources expressly include hydrogen nuclei and alpha particles in the term "cosmic ray." Other sources explicitly exclude those particles in the term "cosmic ray". At least we can agree! Nimur (talk) 04:02, 9 June 2014 (UTC)

What sources exclude protons and other nuclei? To the best of my knowledge no one does that. I think you are just confused about the nature of what we call cosmic rays. Dragons flight (talk) 04:06, 9 June 2014 (UTC)

I think I have to admit defeat here. I even looked up "cosmic ray" in my Sagan/Shklovsky book - and they define cosmic ray to mean "mostly protons." Every other source I can find that defines cosmic ray uses it to mean "mostly protons." It seems the whole world is an apologist for a "historical accident" of terminology!

However, even if that is the case, an informal definition is rampantly used in almost any article or website related to gamma ray astronomy, in which ray really does mean ray! Now that I'm looking into this in gory detail, I see that the term commonly is further qualified as "cosmic gamma ray." But in subsequent discussions, the word "cosmic ray" is used through-out, still in reference to "gamma ray" (in opposition to gamma rays from other sources). For example, EGRET, a sub-instrument of CGRO, uses the term "cosmic gamma ray." Fermi Gamma Ray Space Telescope distinguishes between "cosmic ray" and "cosmic particle." The SLAC website discusses how a cosmic gamma ray may accelerate an individual proton to high energy. Fermi had an entire piece of equipment just to filter out particles and nuclei so they could focus exclusively on the cosmic gamma rays! This NASA article on gamma ray flashes also distinguishes between the gamma ray and the particle jet, though they use the term "cosmic blast" instead of "cosmic ray." The two papers on terrestrial gamma flashes that I linked above also use "ray" to mean ray and not proton. It is possible that I have been guilty of sloppy use of terminology - resulting from my bias towards these specific sub-fields; but it's equally possible that the "historical accident" of terminology is really the issue. In the academic environment in which I studied, we said "proton" when we meant "proton," and "photon" when we meant "photon," and "ray" when we meant radiant electromagnetic energy.

For clarity, and in deference to the many sources and the other contributors who have contradicted my opening statement, I've struck my earlier line. Nimur (talk) 05:12, 9 June 2014 (UTC)

Historically, the sequence of discovery is actually cathode rays, followed by x-rays, alpha rays, beta rays, gamma rays, and then cosmic rays. Of these, four of the things labeled rays involved particles and two involved photons. Given the history of the terminology, I think it would be a mistake to assume that people of the era intended "ray" to mean either just electromagnetic radiation or just energetic particles. More likely, they simply took "ray" from the earlier geometric sense as something which emanates from a point and travels in a straight line. By the way, "radiation" has its root as radiare, i.e. "to emit rays". Dragons flight (talk) 05:45, 9 June 2014 (UTC)

That seems like it would probably be stretching the truth a bit. From Ultra-high-energy cosmic ray, "extreme energy" cosmic rays have an energy > 8 J and the Oh-My-God particle was 50 J. I suppose if you were to compare it to something like the .22 CB, which uses no gunpowder, only the primer, it would have a comparable energy (45 J). And the discontinued-in-1938 2 mm Kolibri had a muzzle energy of 4 J. But using what most people would probably think of when they hear "a bullet fired from a gun" – .38 Special (200-300 J), .44 Magnum (1000-2000 J), .30-06 (4000 J), .50 BMG (20,000 J) – it's a bit of a stretch. An alpha particle traveling at the same velocity as the Oh-My-God particle would have a comparable energy to a bullet. Mr.Z-man 04:16, 9 June 2014 (UTC)

This is perhaps splitting hairs a bit about a series that is subject to the usual journalistic hyperbole (who's going to let a few facts get in the way of a good scientific yarn?). At least the Greisen–Zatsepin–Kuzmin limit article is more specific with its image: (50 joules) of energy (about the same as the kinetic energy of a 60 mph baseball). —Quondum 06:03, 9 June 2014 (UTC)

1. In principle, there is no limit to the kinetic energy energy one can add to a particle. According to our "ultra-high-energy cosmic ray" article, a few cosmic ray particles have been observed with an energy per particle of about 50 J, and each one "was most likely a proton traveling very close to the speed of light". Far from being an unusually massive subatomic particle, a proton is the least massive atomic nucleus, and one of the most common subatomic particles -- although traveling at an uncommon speed. That 50 J is, if I understand correctly, practically all kinetic energy.

I agree with Mr.Z-man that "as much energy as a bullet fired from a gun." is a little misleading.

Technically true, since all the air guns mentioned in our muzzle energy article have a muzzle energy per bullet less than 50 J.

But misleading, since when you mention "bullets" to people around here, they generally think about 9 mm or .45 caliber guns, which the "muzzle energy" article says has a typical a muzzle energy per bullet of 519 J or 564 J, about an order of magnitude more.

2. Yes, such particles will damage the records. Our Voyager Golden Record article mentions that some people believe that "after thousands of years of travel in space, the Voyager probes will be so heavily damaged from micrometeoroid impacts that the disks will likely become unreadable."

I think most people would agree that it is true and non-contradictory that the Rosetta Stone, many clay tablets, some obelisks, many examples of early Chinese art, etc., each have pieces broken off, damaging the writing, but the rest of each object has lasted for millennia.

Likewise I find it plausible and non-contradictory that two golden records will likely have pieces broken off and be damaged in other ways, damaging the writing and other information, but the rest of the golden records will likely last for millenia and perhaps even a billion years. --DavidCary (talk) 06:08, 9 June 2014 (UTC)

Don't high-energy primary cosmic rays, upon first meeting a sitting atom, put most of their kinetic energy into making Cosmic_ray#Secondary_cosmic_rays? In which case, doesn't the impact energy that gets deposited below the aluminum record jacket mostly distribute itself through the volume of material underneath? Including of course the record, but that's much thinner, hence suffers much less of the load, right? Jim.henderson (talk) 18:42, 9 June 2014 (UTC)

Ultra-high-energy cosmic rays are quite rare, with a flux of only about 1 per km² per century, according to the Pierre Auger Observatory article. At that rate, a roughly 0.1 m² Voyager Golden Record would be expected to only encounter one such particle about every 10¹² years, i.e., a record would be unlikely to encounter even a single such particle in the next 10⁹ years. A record will be hit by many cosmic rays with a more typical energy within that time frame, but typical cosmic rays have vastly less energy. Red Act (talk) 02:31, 12 June 2014 (UTC)

Why are the Voyager records on the outside ?

Wouldn't they be better protected from micrometeoroids, etc., if inside the space craft ? Presumably any aliens who find it would take it apart and find the record. StuRat (talk) 14:10, 9 June 2014 (UTC)

Bear in mind that the records are not exposed to space. On one side they are protected by the entire mass of the spacecraft, and on the other, there is a fairly chunky aluminium cover plate that was specifically designed to withstand that kind of punishment. Also, there are two records, each has grooves only on one side and the grooved sides are placed next to each other with the backs of the records facing outwards - so most small impacts either won't make it through the case, or they'll only hit the back of the records without wrecking the grooves. It'll take a fairly energetic event to make a ding in the record itself - and that kind of event should be exceedingly rare. Also, small amounts of destruction may not obliterate enough of the message to make it completely useless.

My biggest concern is the way the instructions for playback are given - those seem hard to understand, even to humans who have enough cultural context. Aliens may be so surprised that a civilization with the capability to send a probe out of the solar system is using an analog mechanical mechanism to transmit this data that they'd fail to understand that the grooves are anything more than a decorative detail on the back side of an otherwise rather interesting commemorative plaque. The record contains greetings spoken in every significant human language...which is useless noise because there is insufficient speech for the aliens to decode any of those languages...then a bunch of sounds like surf and whale-song - but no real indication of what those sounds are. The photos are probably the most useful thing...but without context, it's unclear what (if anything) the aliens could understand from it all.

SteveBaker (talk) 14:21, 9 June 2014 (UTC)

Yea, about as useful as alien sounds would be to us. While they would be interesting, they would be of rather limited scientific value. StuRat (talk) 14:30, 9 June 2014 (UTC)

Are there any scientists reading this who, on being given such a rare and valuable alien artefact, would dismiss it as of "limited scientific value"? I think if we were given an alien disk with absolutely no information on it it would still be guarded jealously and experimented on endlessly. Far from being limited, it would reveal infinitely more information than we currently possess on aliens. SpinningSpark 15:14, 9 June 2014 (UTC)

So look at the number of ancient languages that we have no way to translate because we have insufficient quantities of it to examine and no "rosetta stone" to help us out.

The voyager message is tough to describe - but take a look at another example of our efforts to send messages to the stars - the Arecibo message. It's a long string of 1's and 0's...OK - that's pretty clear. The number of bits in the message is the product of two prime numbers (73x23) - so we will easily guess that this was chosen to give us only a couple of ways of arranging those bits into a rectangle. And when we do, we see some kind of structure emerge with one of the two obvious choices. How the image is rotated or mirrored is unclear (and perhaps, unimportant). We find that in one arrangement, there are binary patterns in either the first (or last) few rows (or maybe columns) of the 23x73 arrangement. But for some reason, the people who sent the message tried to express everything in base-8 with an extra bit that indicates where the least-significant digit is?!? You can read these digits (with the extra bit) in hundreds of different ways - most of which can be kinda made sense of...but it's far from obvious. Then, assuming you can figure out this slightly strange way to represent numbers (alien to even those of us who work with binary numbers all the time!) - the next part of the message contains the numbers: 1,6,7,8,15 - except that they shifted from base-8 to base-16?!? Why on earth did you go to all the trouble to tell the aliens we use base-8 and then switch the encoding? And what the heck are those numbers supposed to mean? Well, according to the creators of the message, those are the atomic numbers of Hydrogen, Carbon, Nitrogen, Oxygen and Phosphor...which are significant because they are the most common elements making up our bodies?!? Well how the heck are you supposed to remotely guess that interpretation? They could be the dates of our holy ceremonies, the number of suckers we have on each of our five tentacles, the number of planets orbiting the five solar systems that we inhabit? Who knows?! Then there are a bunch more numbers - (back in base-8 again): 75010. Which is supposed to say "Our DNA contains the chemical compound C5H7O"...because it's 7 atoms from the first column of the previous table, 5 from the second column and 1 from the next-to-last column. Hmmmm....OK....but it could just as easily be the temperature of our planet, the address of our evil-overlord, or an invitation to trade pig-iron. Who knows?

It gets worse, there is a "picture" of a human being (a stick figure of sorts) and a couple of blobby curves that could be just anything (they "represent" the shape of the double helix...although god knows how?!)...at best, this information can only confuse. Even you or I would have no chance of guessing "DNA double helix" - especially since they ran an ungodly large number (4,294,441,822 - the number of base-pairs believed to be in a DNA helix at the time (the number is more like 3 billion) right through the middle of it. And why to such crazy precision? Everyone has a different number - no scientist would write the number that accurately! How could any civilization realize what the heck this large (and very, very precise) number might be?

There is the number 14 next to the stick figure. What does that mean? There are 14 of us? 14 species? Who would ever guess that the number represents the height of an average human being expressed as a multiple of the wavelength of the message itself? Then there is another number in the 4 billion range - which was the size of the human population on the day the message was sent...but without context, it could be anything. The last thing in the message is supposedly a picture of the Aracibo telescope (it looks more like the curved roof of some kind of a building) - and the size of it.

Honestly there is zero chance of either this, or the Voyager message meaning anything whatever other than "We exist as a technological race". In the case of Voyager, they did put some radioactive uranium in the disks - and from half-life calculations, you could work out when it was made...and assuming you know it's trajectory, you could probably figure out which star it came from. In the case of the Aracibo message, a stream of prime numbers would have been every bit as useful, and a hell of a lot less ambiguous.

To an alien, pictures of a man and woman standing with their arms posed in "universal gestures of peace"(!) could be maps of our major continents for all they have any meaning at all.

These messages are not going to help the aliens who may, or may not find them. They are clearly designed to LOOK like useful messages to us humans - which fulfills the necessary PR goals and makes everyone feel good about ourselves. SteveBaker (talk) 17:15, 9 June 2014 (UTC)

Well, of course the sounds are recorded in analog form. Think of the wide variety of digital coding formats produced by our poor imaginations in the 20th century. Extrapolate from there. So, careful microscopic analysis will show the wriggles, and playing those wriggles will produce a signal whose Fourier analysis will show harmonics. As for twigging that the harmonics are for sound, and as for extracting meaning from the sounds, umm .... Jim.henderson (talk) 18:42, 9 June 2014 (UTC)

The sounds aren't completely useless. Picture the alien commander getting off from a hard day fighting the berserkers to get collared by an excited scientist. "You'll never believe what was on those grooves in that strange space debris you picked up. ... the harmonics sound a lot like the instinctive bleating patterns of some of those organic breeding modules the berserkers use to manufacture their neural tissue..." Wnt (talk) 17:40, 10 June 2014 (UTC)

Horses on Mars

I am wondering if anyone agrees with me that horses can play a great role in Humanity's colonization of Mars. Unlike other machines, horses need no fuel based on petroleum (which is absent from Mars). Wind power cannot be utilized there as there is barely any atmosphere, and the sun's power is much weaker as well. They would eat the same kind of food grown by humans in their greenhouses, i.e. hay etc.

The main difficulty would be suiting up the animals in special space suits. This would require a specially designed helmet, four leg pieces, and a large piece for the torso. Admittedly, suiting up the horse at the beginning of the day would take some time, and of course, the saddle and bridle would then need to be put on afterwards. The oxygen tank would need to be placed, presumably, on the horse's back, although the human rider must also share that space.

Nevertheless, on the positive side, horses would run in a gravitational field a small fraction of our own, and they could breathe air from their tanks which would have a much larger proportion of oxygen than on Earth. On my calculations, those two factors would mean they could gallop at about 80 miles per hour, far faster than any machine, and far more adept at crossing gullies and climbing hills.

When the horse was no longer required for service, it could be used as food, horse meat being most suitable for human consumption, and eaten by many cultures on Earth. Moreover, the horse's droppings could be either collected for use in the greenhouses (via a bag tied to their rear end) or allowed to remain on the plains, where they would become an important part of terraforming. Of course, futurists tend to think only of machines when they imagine the future, but surely there are opportunities for historically proven methods to be utilized. The horse is a magnificent creature with a unique relationship with mankind. To see them galloping over the plains of Mars carrying humans would, I believe, truly be in the best possible tradition of adventure and exploration.Myles325a (talk) 03:59, 9 June 2014 (UTC)

Seems completely implausible to me. Consider the cost of transporting a horse from Earth to Mars. Just providing the resources for a person is challenge enough, but a horse needs more food, more water, and more oxygen. And a horse would lack the intelligence to know to avoid sharp rocks which could tear the suit. There has been a history of animals in space, but those were there to be experimented upon. Work animals in space or on other planets are completely impractical, in the immediate future. In he distant future, however, once Mars is terraformed, then some animals might be put to work. I can picture importing bees as pollinators, for example (hopefully a species we breed to be without a stinger). And we could use earthworms (marsworms ?) to aerate the soil with tunnels. StuRat (talk) 04:34, 9 June 2014 (UTC)

Solar power works fine on Mars. HiLo48 (talk) 05:38, 9 June 2014 (UTC)

You've got to be kidding. (I mean really, you are kidding, right?) Horses are solar powered... they just eat their "solar panels", and it takes a lot of them to sustain one horse. Solar electric cell to electric motor is a very simple and efficient mechanism, as well documented by the Mars rovers.

Now to be sure, with high tech horses might at some point surpass electronics in self replication, if we allow for genetic engineers to be very clever and nanotech designers not so much. I can picture designing lichens to grow on Mars, and horses that are genetically altered to withstand vacuum; they no longer have lungs but take in large amounts of chlorate containing rock with their lichen, and their intestines effectively transport that to some new organs you've lined the intestine with that extract the oxygen produced from it. Their fur would have to take after a musk ox, though; even so they would need to eat more than terrestrial horses to deal with the cold, including the heat requirements of melting ice deposits to get water. Once a horse is free to graze the paddocks of Mars, all you need is a lasso and a sense of adventure. :) Wnt (talk) 06:09, 9 June 2014 (UTC)

OP myles325a back live. This obviously raises (NOT "begs") the question that if you can genetically alter the phenomes and genomes of horses, then why not humans? I firmly believe that human interplanetary and interstellar travel will inevitably involve radical and artificially induced changes to the human genome. In the future, commentators will be puzzled to see how rarely sci-fi writers visualized different types of humans, designed to be compatible with environments very different to Earth’s. We are coming to a time when many genetic changes will be made with relative ease, and taking effect within one generation. The obvious ones include abilities to function in a near-vacuum, be resistant to radiation, eyesight that is sensitive to infrared and microwaves and can function in near total darkness, ability to function in very cold and hot temperatures, ability to hibernate for long periods of time, in-built communication devices (thus the antennae on “little green men”) and suction pads on legs and arms allowing for better movement in low gravity. And much more.

But in my question, I am thinking of horses (and humans) just as they are now. Myles325a (talk) 07:13, 12 June 2014 (UTC)

So go ahead and write a science fiction story about cowboys, horse, cattle and rustlers on Mars. Sell it for download on Amazon or wherever. I'd take a look at it. Edison (talk) 13:03, 9 June 2014 (UTC)

In the end, solar energy grows plants - which feeds horses - which produce propulsion. Or...Solar energy charges batteries - which drives motors - which produce propulsion. Sure, horses are useful as food when they die - but that's because they consumed far more plants (and therefore more solar energy) during their lives than was needed just for propulsion. You can repair an electric quad-bike, you can't repair a horse. Horses need oxygen and water - both of which are valuable and costly resources on Mars. They consume food, water and oxygen even when you're not using them for transportation. Your electric quad-bike will happily sit outside in Mars atmosphere and consume no resources whatever until you need it. Horses are an incredibly inefficient way to get around unless oxygen and water are free and food is cheap (as here on earth).

I also wonder how well they'd adapt to Mars gravity...they have highly tuned locomotive systems and it's far from clear how well they'd do on Mars.

SteveBaker (talk) 13:48, 9 June 2014 (UTC)

OP myles325a back live. Well, Steve, the same objection could be made with humans. If we can get by in reduced gravity, then why not them? Frankly, I think they would get a real “kick” from being able to gallop faster and jump higher than they could ever do on Earth. Now that I think of it, there should be microphones (and sound receivers) in their space helmets so that when they whinny, other horses can hear them. It would be cruel to deny horses the opportunity to express themselves in their ancient “language”. Myles325a (talk) 07:22, 12 June 2014 (UTC)

While I agree that horses on Mars are impractical, note that they are self-repairing, as are all life forms. Also, some repairs that they can't make on their own can be assisted by a vet or caregiver (such as removing a stone from their hoof). StuRat (talk) 14:14, 9 June 2014 (UTC)

OP myles325a back live. Well, you’ve hit the nail right on the head there. The horses’ hooves would be covered by the space suit, which would have toughened areas where their hooves strike the ground. No need for farriers on Mars! In fact there could be specially designed surfaces to cover their hooves for special jobs. Such might include suction caps or Velcro pads for when they are needed to haul equipment on metal ramps and the like, or on surfaces with steep inclines. Myles325a (talk) 07:30, 12 June 2014 (UTC)

Time to weld a broken suspension strut? An hour to remove it, weld it and put it back on again? How long for a broken bone to mend on a horse? Generally they shoot horses with broken bones - it's that hard to deal with. On Mars, the cost in lost food/water/oxygen while the horse recovers in a plaster cast for a couple of months would be crazy!

You might be able to put a brace on the horse's leg that would allow it to continue to work while the leg was healing. And what happens if the machine repair requires parts they don't have on Mars ? If they are smart enough to have multiple units, they can cannabalize some to get spare parts for those they keep running, but only for so long. StuRat (talk) 00:19, 10 June 2014 (UTC)

OK, WPEQ has galloped into assess the situation. Let's see. Factor into your calculations that a horse needs to consume between about 1.5% and 2.5% of their weight in forage each day and 10-12 gallons of water (figure the average horse at 1000 lb), though a pony is smaller and more efficient in their use of feed. Add to that that in waste product, the average-sized horse will also generate between 35- 50 pounds of manure a day and on top of that about 6-10 gallons of urine. Due to their size, simple respiration also puts a LOT of moisture into the atmosphere and so in an enclosed stabling setting, there would be a significant condensation problem to consider. Now, for shipping into space, embryos are no doubt the way to go, with artificial wombs for incubation, so that would be manageable, but it would take a minimum of two years before they would be mature enough to do any sort of heavy work. On the other hand, the horse actually evolved in the ice age, and so adaptation to a colder climate would not be the challenge one might think (consider the Pit pony as a case in point) Horses and ponies are also quite nimble and would be superior for moving around on rough terrain (donkeys might be even better) but certainly the issue of space suits or genetic modification would be significant, might want to wait until there has been a bit of terraforming before adding them to the ecosystem. Also consider that they are prey animals and prone to panic at unexpected times, using biting and kicking as a way to get themselves free, not ideal in a setting where plastic membranes might be the only thing between civilization and a vacuum. OTOH, if the shelter can withstand a Martian sandstorm from the outside, then perhaps a few horses kicking from the inside is no big deal.  ;-) Montanabw^(talk) 02:43, 10 June 2014 (UTC)

OP myles325a back live. Nope Monababw, I’m not in favour of ponies on Mars, no way. Neither would the intrepid settlers of another world be happy with them. This is the New West, full of pioneers! They aren’t going to be moseying down the garden path like a bunch of schoolgirls giggling on their show ponies at some adventure camp. There will be horse races of course, and legends will surround the best ones, as they do Phar Lap. When the horse is butchered, the settlers will eat all of it, except its heart, which will be plasticated, and put in a special display case with a statue of it in its full space regalia galloping at full tilt. What a sight that would be> Myles325a (talk) 07:40, 12 June 2014 (UTC)

Horses will be introduced when we have significant grasslands on mars, well into terraforming. the ideal form would be a small one, like the early horses, and see how mars evolves them. first, though, we would need genetically modified reindeer, or a reindeer/horse engineered hybrid, for lichen consumption. the animals dung would of course help the terraforming process. i can imagine herds of up to 1 million small, highly sociable horses, like the great plains buffalo. maybe we can then breed a centaur, and let THEM own the planet. they would be great warriors, after all. see Mars Trilogy and "Titan" by John Varley for background on this.Mercurywoodrose (talk) 05:54, 10 June 2014 (UTC)

Well, the most straightforward way to get them to Mars :) is the universal womb, an organ designed to carry and accurately archive the genomes of millions of different species (maybe per Deinococcus radiodurans), and to appear unobtrusively at a specific spot in the anatomy of each, directing the production of such organisms as are permitted by its size and appropriate given the organ's sampling of ecological parameters such as air and water composition and the nutritional and population parameters of the host species. That way you can bring a daisy, the daisy breeds a honeybee, the honeybee breeds a bumblebee, etc., until it is ready to pull a horse out of its genetic archive. You mess with global warming, nuclear war, planetary bombardment etc. you end up needing this kind of stuff. Wnt (talk) 17:48, 10 June 2014 (UTC)

I don't believe colonization of Mars will ever be possible. It is a totally absurd idea horses or not. Besides horses need normal atmosphere but on Mars you have no oxygen in the air and the air pressure is just one percent of that on the Earth. --AboutFace 22 (talk) 01:06, 11 June 2014 (UTC)

Never say never. (OK, technically you said "ever".) Given thousands of years, we ought to be able to do it. The problem isn't a technical one so much as a political one. That is, how do you sell the population on a project where the benefits will only be reaped long after everyone they know will be dead ? So, perhaps we need to dramatically expand lifespans first, then take on projects like this. StuRat (talk) 16:36, 11 June 2014 (UTC)

It is shocking how some totally absurd questions attract so many contributions. Horses on Mars? It is so bizarre!! You, StuRat are an incorrigible optimist. I doubt the mankind has a thousand years in its future given what is going on now on the world scene. How about global warming and other threats? Half the people who contribute here don't seem to have their marbles in place and you are talking about going to Mars! Mars is a dead planet with a hostile environment for humans. There is no water, no oxygen, no soil to plant anything. You have to bring tons and tons of supplies and equipment with the first (hypothetical) colonists. Let's start with the toilets. And how about energy. The Sun is far away and you can hardly generate enough energy to have a small robot moving. You need five orders of magnitude more than that to sustain a colony. Are you planning to bring a nuclear power station with you? You guys are all participants of a bad dream. --AboutFace 22 (talk) 20:42, 11 June 2014 (UTC)

1) Global warming is not a threat to human existence, only a problem for those living in coastal areas. They will need to move to higher ground. A major inconvenience, yes, a threat to our survival, no. StuRat (talk) 21:06, 11 June 2014 (UTC)

OP myles325a back live. I agree with all these points Sturat, except for this one. I really am surprised that you seem to think that rising sea levels is the only serious implication for humans with global warming. Think about violent hurricanes which can level cities, temperatures of a hundred Farenheit for months on end in places like Australia, severe droughts and floods and much more besides. And the effect could well be a run-away one too. We now know that global warming is what made Venus the raging furnace it is today. We could be just like Venus in two hundred years time, and that's a blink of an eye in Earth's history. Myles325a (talk) 07:49, 12 June 2014 (UTC)

I doubt if hurricanes can level a city. To do that they would need an energy driver such as hundred degree water, but when the ocean water reaches 80F, smaller hurricanes spawn and use up that thermal energy, while cooling the water. So, you might well get more hurricanes, and the hurricane season may expand, but they shouldn't get much more severe. Moving inland from coastal areas isn't just because of rising sea levels, but also because of increased hurricane activity. Hurricane strength rapidly decreases as they head inland and lose their energy source.

As for severe droughts and floods, we've always had those. They may be in new areas as a result of global climate change, but some previously uninhabitable regions may also become hospitable to humans, such as northern Canada. So, again the answer is to move, towards the poles, in most cases. Again, major inconvenience, yes, end of humanity, no.

And there's no danger of the Earth turning out like Venus. It has a much thicker atmosphere than Earth, with a completely different mix of gases. Nothing we could do could change our atmosphere into that of Venus. And, of course, it's much closer to the Sun.

Also, the Earth was far hotter in the past, when dinosaurs lived at the poles. We won't get anywhere near that hot, but even if it did get that hot, we'd just populate Antarctica. Certainly not something we could do immediately, but over hundreds of years we could. StuRat (talk) 23:22, 15 June 2014 (UTC)

2) There is likely water on Mars; at the poles, in craters, and undergound. Water can then be broken up into oxygen and hydrogen. Nowhere near as much water as on Earth, to be sure, but we have far more water than we need. (The problems on Earth with water shortages are just a distribution issue.)

3) Soil is little more than sand, water, and some organic mater mixed in, and we will soon have all the ingredients for that. Manure from people is the most likely short term source of the "organic material". There are also primitive life forms, such as lichen, which can grow without soil.

4) Solar energy is better than you might think on Mars. True, the Sun is weaker there, but they also lack the storms and clouds we have on Earth, which darken the sky and damage solar panels. You also don't have to worry about trees blocking the sunlight, at least not until it's been terraformed. The thinner Martian atmosphere also absorbs less of the sunlight, especially UV.

5) Nuclear power isn't a bad option, either. Most of the mass of a nuclear reactor is safety equipment, but you don't need that if the only people there are protected under domes. Any radiation that escaped would dissipate long before Mars' atmosphere was breathable, in any case. StuRat (talk) 21:06, 11 June 2014 (UTC)

AboutFace, speaking only for myself, I am finding this an amusing thought game. Might be useful for a science fiction novel someday for someone. Interesting to think about. Please find your sense of humor because dreaming is but the beginning of the creative process. I for one am quite grateful for cordless power tools and other spinoffs from the Apollo program. That said, yes we have problems on earth, but it is dreaming that generates the creativity that can solve them. Montanabw^(talk) 22:06, 11 June 2014 (UTC)

StuRat, I wish that just now and then you would consult a source before leaping in with an answer from your own half-baked thoughts. There are extraordinary planet-wide dust storms on Mars that can last for months and severely darken the sky. They certainly do effect solar panels, the Mars rovers have been temporarily shut down in the past through lack of power caused by dust storms. I don't think I would trust you as the safety manager of a nuclear plant on Mars either. SpinningSpark 22:34, 11 June 2014 (UTC)

Your link says nothing about "extraordinary planet-wide dust storms on Mars that can last for months and severely darken the sky". It does mention that some sand gets blown into the air and creates very thin clouds, but that's not the same thing at all. StuRat (talk) 23:28, 11 June 2014 (UTC)

• "planet-wide dust storm with only the giant volcano Olympus Mons showing above the haze"
• "The storm lasted for a month, an occurrence scientists have since learned is quite common on Mars"
• "reducing the amount of energy provided by the solar panels and necessitating the shut-down of most science experiments"

See also this NASA page, and this one "Two months after sky-darkening dust from severe storms nearly killed NASA's Mars exploration rovers".... SpinningSpark 00:47, 12 June 2014 (UTC)

OK, I stand corrected on that point (I did a search on "sand storms" not "dust storms", in the article, and found nothing). However, the fact that the rovers were able to use solar panels for years indicates that it's not as dire a situation as you portray. A colony would of course have far more and bigger solar panels, and people to clean and maintain them, so they should produce far more electricity than the rovers' did. StuRat (talk) 03:25, 12 June 2014 (UTC)

I admire your enthusiasm, that's for sure but I think you don't grasp the magnitude of the problem. You remind me of what is going on in Brazil now with the World Soccer Cup. People of the third world country subscribed for a task that is beyond their organizational skills and here is the result. Mars does not have magnetosphere and as a result it is bombarded by cosmic rays all the time. When the robotic rovers were traveling to Mars it was calculated that they were exposed to the amount of radiation that had there been humans their cancer rate would have been raised by 5% and it is in the absence of the solar flares! NASA was lucky in this respect, the Sun turned out very understanding and merciful for a time. Then let's assume the colony on Mars has been set up. What is the benefit for us, normal people? Mars can be studied by robots. What would we gain having live people over there with a trillion dollar investment in their every breath? --AboutFace 22 (talk) 01:52, 12 June 2014 (UTC)

The benefits would be extremely long term. After a self-sustaining colony was set up, any catastrophe that destroys all life on Earth would have a fair chance of sparing Mars, and thus humanity would survive. Again, we're talking about thousands of years from now. StuRat (talk) 03:19, 12 June 2014 (UTC)

Whoa people! We were talking about horses on Mars, not human exploration! LOL! Montanabw^(talk) 04:04, 12 June 2014 (UTC)

OP myles325a back live. Yes Montababw, you are right. Space exploration of any kind, let alone the ultimate goal of interplanetary settlement, requires a population which is ready to pay big taxes without seeing anything much in the way of profit for hundreds of years. The U.S. did this when it racing the Ruskies in space. But when it won the Cold War, the population went cold on space exploration except for relatively cheap robotic explorers. Perhaps the self-interested of democracy works against such massive projects.

They bleat: "Oh we want more hospitals and schools...more money for pensioners. It's cruel to send horses into space, and expensive. I want my hemorrhoids fixed up for free. I want medical marihuana not space flights “(Frankly, I’d convict many of them and send them to work on the Moon for a few years. A bit of hard yakka wouldn’t hurt them at all.

Like, society becomes a hospital with no sense of adventure. Would Americans ever build a Great Wall like the Chinese did? They would have once, not now. Perhaps a benign dictatorship (or even one not-so-benign) is needed to undertake such projects which take many generations to achieve. Myles325a (talk)

Reminder: WP:SOAPBOX. 84.209.89.214 (talk) 13:34, 12 June 2014 (UTC)

The Great Wall of China was built for an immediate benefit, to stop Mongol invaders. Likewise, the US is building a wall at the Mexican border for the immediate benefit of curtailing illegal immigration. As for our space exploration in Earth orbit, this has had lots of immediate benefits, like allowing for satellite communications, GPS, spy satellites, etc. Human Mars exploration would give us fewer immediate tangible benefits, but there would be some, like superior recycling technology we would need to develop for the trip. Also, osteoporosis is both a problem of the elderly and from low-gravity, so a solution to that might be applicable here on Earth, too. StuRat (talk) 14:04, 12 June 2014 (UTC)

OP myles325a back live. The Great Wall of China took hundreds of years to build, and almost bankrupted the state. It is a perfect example of a State making very expensive and very long term investments, something a democratic government could never do. In this case, that would have been a good thing, as the Wall was a failure. But I am reminded of a decision by Holland to grow stands of perfectly formed conifers. These came to maturity FOUR HUNDRED YEARS later, in the 1970s I think. Their purpose? To be masts on sailing ships. (I will have to get the full details on this. Sounds like an historical myth, but I am assured it is not…) Myles325a (talk) 02:09, 15 June 2014 (UTC)

• My congratulations to the original poster, who has taken a self-evidently nutty idea (comments above, passim), and managed to keep people talking about it for all this time! RomanSpa (talk) 18:54, 12 June 2014 (UTC)

A piece of information for the future martians. Every minute the Apollo astronauts spent on the moon cost the US two million dollars. Also how are you planning to protect against meteorites? You will be close to the Asteroid Belt. --AboutFace 22 (talk) 02:39, 13 June 2014 (UTC)

OP myles3235a back live. But AboutFace, you should rem that the first new microchip costs 50 million dollars to make. The second costs 10 cents. Same with the space program. Perhaps we can charge rich tourists to go there, and them make them slaves when they reach Mars BaseMyles325a (talk) 02:09, 15 June 2014 (UTC)

A) Cost will go down with increased volume, improved technology, and getting private industry involved. One thing NASA does that wastes money is to completely redesign almost every ship they send to Mars, from scratch. When they have a successful mission, like the Opportunity rover and Spirit rover, they should send many more just like that. They could put new instruments aboard, but should not redesign the basic platform, as that only increases costs and the chance of mission failure. In the case of colonizing Mars, once we design a ship that can deliver people and supplies, we should keep using that design, and only redesign it when technology significantly changes.

B) The thinner Martian atmosphere might also make small meteors more likely to make it to the ground. However, meteors are such a minor risk here on Earth that even a bigger risk on Mars might still be something you could just ignore. For example, if your risk of being killed by a meteor is one in a billion on Earth and one in a million on Mars, people would still be willing to take that risk. (Does anyone have the actual figures ?) StuRat (talk) 14:40, 13 June 2014 (UTC)

OP myles3235a back live. Agree. Possibility still small. Radiation bigger problem. Need to develop special creams to apply to skin. A la sun cream. Am now talking telegraphese. Don't know why. New idea. Special conical space helmets covering head and shoulders. Meteorite hits cone. Is deflected down cone. Mars settlers now referred to as "cone heads". Myles325a (talk) 02:09, 15 June 2014 (UTC)

Work animals are sometimes discussed in the context of space exploration, especially in science fiction, but only after the planet is terraformed.

The primary advantage of a Horse over an electric car is that the electric car requires a high level of technology and resources to manufacture and would probably have to be shipped from Earth, while horses pretty much manufacture themselves locally. However, that advantage goes completely out the airlock if you have to manufacture spacesuits to put the horses in. At the point that you're manufacturing the suit, you might as well just skip a step and just make an electric buggy. APL (talk) 17:38, 13 June 2014 (UTC)

OP myles3235a back live. Much easier to sew up horse suit on base than build electric car. Also will last longer. No fancy chips. Myles325a (talk) 02:09, 15 June 2014 (UTC)

I'm afraid you're wrong. Spacesuits are very complicated pieces of equipment. They're not just jumpsuits with helmets. It would honestly be easier to build a simple buggy like they used on the moon than it would be to build a horse-sized suit designed to be used by a being who could not work the controls! (So it would need a lot more automation and computer control than existing space-suits.) APL (talk) 21:29, 15 June 2014 (UTC)

Wilf Carter, "Strawberry Roan" (but unfortunately not on Mars) Bus stop (talk) 23:28, 15 June 2014 (UTC)

Need super-high resistance wire for modified hair curler.

I'm modifying a hair curler to use a smaller barrel to tame my wild moustache. I need to replace the resistance wire as well as the barrel because the original burned up. I want to replace it with a higher resistance wire beside the barrel is smaller. The problem is that I can't find anything with anywhere near the required resistance of at least 67 Kohms (that's what the original was. I'd like something more like 100 Kohm) per meter. What kind of resistance wire/alloy should I be looking for?

That sounds implausibly high for any kind of resistance wire I am familiar with. What gauge wire are you looking for? The commonly used nichrome for instance, at 32 AWG has a resistance of about 30 ohm/metre and constantan is about half that. 100 kohm/m is more like a poor insulator than a conducting wire, the sort of conductivity one gets from conductive plastic (why is that a redlink? someone write an article please). SpinningSpark 08:35, 9 June 2014 (UTC)

Looking at it another way, 6 inches of 100 kΩ/m wire is about 16 kΩ. At 230 V (you're in Europe, right?) that will dissipate only about 3 W, rather less than a low-energy light bulb that you can hold comfortably hold in your hand while it is on. I don't know what wattage heated rollers use, but typically they get to over 100°C. There is no way 3 W is going to do that for you. SpinningSpark 09:32, 9 June 2014 (UTC)

The technical term is conductive polymer. 24.5.122.13 (talk) 09:27, 9 June 2014 (UTC)

That's not really what I had in mind. That article is about intrinsically conductive polymers, which, according to that article, are not usually thermoplastic. I was thinking of a regular polymer loaded with carbon or silver. SpinningSpark 11:23, 9 June 2014 (UTC)

Do you really want a thermoplastic polymer for a high-temperature application such as this??? 24.5.122.13 (talk) 20:48, 10 June 2014 (UTC)

soldering irons manage it. They get up to crazy temperatures - even on 110 volts. They are much smaller in diameter than hair curling irons - so they fit the bill there too. You can buy soldering irons with adjustable temperatures - maybe one of those is what you need? The one on in the image (right) has a temperature scale that runs from 150 to 450 degC - and this article says that professional curling irons produce 175 to 400 degC...so this seems plausible. (I find this all kinda terrifying though - the idea of having a hot soldering iron with my moustache hair wrapped around it....yikes! SteveBaker (talk) 13:40, 9 June 2014 (UTC)

I think curlers get disconnected from the supply before actually going in the hair. In fact, the heating element is not in the curler at all, it's part of the base. Or else they work by induction, but in any case, there are no physical wires to the curler. I have a soldering iron in my shed almost identical to the one in the picture. It's rating plate says 50 W, and that's only to heat up a tiny tip, not a big curler; my case rests. SpinningSpark 14:41, 9 June 2014 (UTC)

That sort of resistance per unit length might be found in the filament of an incandescent torch bulb, but I agree with Spinningspark that you would need exceptional insulation to achieve those temperatures with an input of only three watts. I suspect that the 67,000 ohms was measured after the filament had burnt out because it would give a power output of less than one watt. You probably need nichrome wire of the order of five or ten kΩ/m (e.g 0.014mm diameter 55awg 6793 Ohm/m) but this will be a very fine and fragile, and there are safety factors to take into consideration. How will you prevent overheating? Dbfirs 18:59, 9 June 2014 (UTC)

"That sort of resistance per unit length might be found in the filament of an incandescent torch bulb..." Naaaah, a 12 V, 1 A torch bulb has a resistance of only 12 Ω. Even a 60 W, 240 V bulb only has a resistance of 960 Ω. And that's while it's hot, it's only about 20 Ω cold (tungsten has a coefficient of resistance of about 0.004/°C) which is the resistance that you would measure. The resistivity of tungsten is only about four times greater than copper. @Seans Potato Business: are you sure your meter is accurate? Have you tried connecting the probes together to see if the meter reads zero? SpinningSpark 19:37, 9 June 2014 (UTC)

Yes, you're right, I don't know what I was thinking of there. Dbfirs 20:04, 9 June 2014 (UTC)

I've checked using resistors that I own, and the meter appears to be accurate. --Seans Potato Business 05:07, 10 June 2014 (UTC)

Hello all, this is the OP. There are some misconceptions to clear up. The wire is about 6 cm, not 6 inches so according to my calculation, the power is closer to 13 W. I measured the resistance BEFORE the wire was broken and the resistance was 3.9 Kohm. Finally, the curler is all one piece and the device is used whilst plugged into the outlet. The device looks like this - edited due to copy/paste error --Seans Potato Business 19:33, 9 June 2014 (UTC)

Hmm ... those calculations sound accurate, in which case the wire must have a higher resistivity than nichrome. I wonder what it was. Dbfirs 20:04, 9 June 2014 (UTC)

Nerve endings in fat

Does fat have nerve endings? Why is it that runners often claim to feel pain in fat while running? I know they feel pain in bone and muscle a lot as running is quite hard on bones and muscle but why fat? Clover345 (talk) 11:56, 9 June 2014 (UTC)

Fat does not contain nerve tissue. I've never heard of joggers having "fat" pain, but I imagine it's the stuff the fat's connected to, and not the fat that they are feeling.Zzubnik (talk) 12:21, 9 June 2014 (UTC)

(Strictly speaking, adipose tissue (fat) does contain nerves, but so far as we know it's just linked to the sympathetic nervous system, primarily for the purposes of regulating the body's fat and energy inventory: [1]. It's not a source of pain signals.) TenOfAllTrades(talk) 12:57, 9 June 2014 (UTC)

Thanks for the clarification! Zzubnik (talk) 10:11, 10 June 2014 (UTC)

Can people see clearly underwater ?

This might seem like a silly question, but I've been nearsighted since an early age, and can't wear glasses or contacts in the pool, so everything always looks blurry underwater to me. Can those with good eyesight see clearly underwater, or do the shifting currents, etc., make it blurry for them, as well ? StuRat (talk) 14:20, 9 June 2014 (UTC)

With goggles on, sure. In practice a swimming pool is often fairly cloudy, meaning you might be able to see maybe 10 metres; our local pool has rather ancient plant which occasionally puts lots of air bubbles into the water, making it eerily milky and reducing visibility to a few feet. -- Finlay McWalterᚠTalk 14:27, 9 June 2014 (UTC)

There's some type of underwater plant in your local pool ? StuRat (talk) 14:32, 9 June 2014 (UTC)

Plant meaning machinery. -- Finlay McWalterᚠTalk 15:27, 9 June 2014 (UTC)

Hence this British sign. --69.158.92.137 (talk) 03:35, 11 June 2014 (UTC)

I picture a giant redwood dashing across the street. :-) StuRat (talk) 16:29, 11 June 2014 (UTC)

Must be British English. In US English, we occasionally use "plant" to mean a collection of machinery, like "power plant", but I would never call a single machine a "plant". StuRat (talk) 16:32, 11 June 2014 (UTC)

• Underwater vision Wnt (talk) 15:14, 9 June 2014 (UTC)

It really depends on the condition of the water itself of course (temperature, cleanliness, chlorine content, etc) but generally speaking, yes, for those of us with good eyesight underwater vision can be quite good. Sebastian Garth (talk) 15:49, 9 June 2014 (UTC)

The article uses the phrase "extremely blurred image", and indicates that people with myopia may have better focus underwater. If you are trained to reduce your pupil size underwater, or the lighting is very bright, vision can be quite good, but often it is not so great. "Shifting currents" would not be expected to have an effect, though. —Quondum 16:15, 9 June 2014 (UTC)

Also have a look at Sea Gypsies of Asia Boast "Incredible" Underwater Vision. Alansplodge (talk) 17:45, 9 June 2014 (UTC)

That is interesting, thanks. Apparently they constrict their pupils so they behave more like pinhole lenses. StuRat (talk) 22:32, 9 June 2014 (UTC)

I became short sighted in my mid-to-late teens, and remember swimming underwater in my local swimming pools regularly before that. It was very blurry, I could only see clearly wearing goggles. It's still blurry, although I can't tell if the blurriness has changed. I don't remember what it looked like to swim under the sea when I had good eyesight.--Genandrar (talk) 17:54, 9 June 2014 (UTC)

• I remember being able to see quite clearly in clean fresh water as a child when we practised early in the day for swim team at the town pool. I am now shortsighted in the left and farsighted in the right eye (one for reading, t'other for driving) and haven't tried the experiment in 35 years at least. μηδείς (talk) 03:48, 10 June 2014 (UTC)

I don't wear any correctives. I had perfect sight until I noticed shortsightedness in my late twenties in the left eye. I found it hard to read signs at a distance on the Jersey turnpike.. Then my right eye started having difficulty seeing with enough focus to read newsprint closer the extended arms length. My nephews hand things to me to read about 1 foot from my face and I make a show of gaping and squinting until I settle on about 3 feet. Given the overlapse at 3 feet, I really don't run into many issues. μηδείς (talk) 17:42, 10 June 2014 (UTC)

• Are you actually nearsighted in one eye and farsighted in the other, or do you just wear a single contact lens, as I do. I ask because I've never heard of that condition before. StuRat (talk) 15:24, 10 June 2014 (UTC)

Maybe the question needs clarification (no pun intended). Without diving mask or goggles, underwater vision is generally blurry. This is because the index of refraction of the lens in the eye is very close to that of water, and hence the lens cannot perform its usual function of focussing the image onto the retina. If you wear plain swimming goggles (so the lens is in contact with air), vision depends very much on the conditions of the water and the available light. In a clean pool or in the John Pennekamp Coral Reef State Park under a clear sky you can easily see 50m or so, and vision is generally sharp and clear. Diving by night in Miami, or after a storm that disturbed sediments off Sihanoukville, I've also experienced visibility of less than 5m. We do have an article on underwater vision, btw. --Stephan Schulz (talk) 15:48, 10 June 2014 (UTC)

Yep, Wnt linked to that above. StuRat (talk) 20:22, 10 June 2014 (UTC)

The reason why human vision is blurry underwater is described in the article Wnt linked to, and is not as Stephan said that the index of refraction of the lens in the eye is close to that of water (come on, the lens is surrounded by water whether we are swimming underwater or not). The point is that our ability to focus primarily depends on the cornea, which is normally is surrounded by air, and whose refractive index is close to that of water. In humans, the lens only makes a smaller, but adjustable contribution, such that we are able to focus at different distances. Animals who have an acute vision both above and below water, such as dolphins, have flat corneae, and depend only on their lenses for focusing. --NorwegianBlue ^talk 21:29, 11 June 2014 (UTC)

Thanks. I didn't understand that so clearly (or maybe it's a false friend language-wise. --Stephan Schulz (talk) 23:32, 11 June 2014 (UTC)

Can humans see antimatter and matter annihilate?

Let's say 10,000 tons of matter and antimatter met in space in the solar system. What would humans watching the annihilation from within the solar system see? Would it look any different in space of a different density? On Earth, would the explosion look more traditional as the radiation interacted with surrounding matter?--Genandrar (talk) 17:49, 9 June 2014 (UTC)

This would depend very much on how fast the annihilation occurred and how far the event was from the observers. Perhaps an expert can do some accurate calculations, but if it occurred in a time of one second at a point nearly diametrically opposite Earth on the other side of the sun then I think we would hardly notice the flash compared with the photon output the sun (less than 0.1% of the sun's brightness, but someone had better check my estimate). I was initially puzzled by the concept of density of space, but perhaps you mean the density of matter in what we call "empty space" which can be as low as one atom per cubic metre, but is higher within the solar system. I don't think this would make a significant difference. Dbfirs 18:39, 9 June 2014 (UTC)

There is a potential 9x10 with 23 zeros joules of energy which isn't much different from the energy released by the sun each second but in reality a lot of it won't be released due to the explosion separating the particles. What it looks like depends on the matter. The initial energy release is gamma rays so they'd need to interact with something else to be changed into visible light. --Seans Potato Business 20:02, 9 June 2014 (UTC)

I'd forgotten that 99.something percent of the sun's loss of mass is carried away in the form of mass-carrying particles, not photons. If the output were mainly gamma radiation from perfect matching of matter with anti-matter (how would you achieve this?) then the density of matter in "empty space" would be significant, and the human observers might be at risk, but would not the first few million atoms of annihilation heat up the rest of the matter and antimatter to emit photons? I suppose we've too many variables to make an accurate prediction. Dbfirs 20:10, 9 June 2014 (UTC)

(ec) My calculation is that if 10,000 tons annihilated completely, the energy released would be right around 10²⁶ Joules, roughly the amount of energy the Sun releases in one second. So if it all annihilated at once, you could get a very bright flash. But getting it all to annihilate at once would be very challenging, because if you brought two chunks together, the energy generated at the interface would blow the whole thing apart in a tiny fraction of a second, and only a tiny percentage would react. If this took place on Earth, the energy released would be equivalent to the energy the Sun delivers to the Earth in 30 years, so the effects would obviously be, um, noticeable. Looie496 (talk) 20:11, 9 June 2014 (UTC)

Hmm did you make a mistake in your calculations? I seem to get the same figure as SPB if I'm not misunderstanding Mass–energy equivalence and/or matter-antimatter annhilation and/or Google's calculator isn't screwed. Nil Einne (talk) 19:00, 10 June 2014 (UTC)

Exponential Accumulation of Human Knowledge (Georges Anderla)

In 1973 the economist Georges Anderla developed a statistical model of the accumulation of human knowledge. The model demonstrated a periodic and accelerating doubling of human knowledge, culminating in 1973 when according to Anderla, "the amount of human knowledge was 128 times greater than in the year 1 AD" and was doubling every six years. Of interest is that the model terminated in 1973, well before the proliferation of personal computers and the Internet.

Questions:

1. Are there any more recent, similar studies of the doubling or rate of accumulation of human knowledge and its acceleration? (I have searched well and inquired on many other forums but have found nothing.)

2. Where might one look for more recent, similar models, in which field of study)? (This model was by an economist but is there a more appropriate field I should target?)

3. How might one find a copy of Anderla's model? (I have searched the OECD library, referenced on the Wikipedia page, but the study is not found there. I also found what I think is a transcribed lecture, "The Growth of scientific and technical information, a challenge : lecture and seminar proceedings, J. Georges Anderla, Paris University (The Sorbonne)." and a few other published papers but I think none is the actual study in question.)

4. How might one best determine if Anderla's model was statistically accurate?

5. If Anderla's model was accurate, but no similar and more recent models exist, is there a method by which one might extrapolate Anderla's data into the present, taking into account especially the later proliferation of personal computers and the Internet?

Thank you for any and all advice.

Edit: added the research I have undertaken without result.

Rldioxin (talk) 18:25, 9 June 2014 (UTC)

It looks like the OECD work might have ISBN 9264110933. The model might be specified in these conference proceedings [2]. To get access to either, you will probably have best luck at a physical library, using inter-library loan. You could also try at WP:REX. This is not my field, but one thing I know of that is a popular area of current research is information behavior, which is a subfield of information science, see overview here [3]. Information science has many subfields, such as information retrieval and information organization. Some parts of it feel a lot like applied computer science, while other parts of it feel more like library science, or even social science. Finally, note that just defining, let lone quantifying "human knowledge" is no short order, and the choices made there will of course have strong influence on what models might imply. SemanticMantis (talk) 19:29, 9 June 2014 (UTC)

Thanks, the Wikipedia page often refers to 'human knowledge' but then says Anderla " ... began by defining the known technology in 1 AD as a unit ... " so I'll assume the confusion is on the part of the author of Anderla's page. I'll consider correcting this at such time that I'm certain. — Preceding unsigned comment added by Rldioxin (talk • contribs) 19:48, 9 June 2014 (UTC)

More specific to computational technology, there's Moore's_law#Other_formulations_and_similar_laws. SemanticMantis (talk) 20:20, 9 June 2014 (UTC)

I believe the book Future Shock was based on a similar concept. Note that while the bits of data, in as much as it can be computed, might well double every 6 years, the more information we have, the less useful it is, on average. It's an application of the law of diminishing returns. The information people had access to in the year 1 AD would have been rather useful to them, like how to farm and herd animals. The cost of distributing useless information was just too high, so it didn't much happen. But these days, everyone can follow the lives of the Kardashians at almost no cost to them (other than their wasted lives, of course). There's also a lot more highly specialized knowledge these days, that, while useful to some, is not useful to most, like the genetics of the fruit fly. So, the amount of useful information to the average person is likely going up far slower than total information. StuRat (talk) 22:17, 9 June 2014 (UTC)

Gosnell Hall floor

On a recent trip to Rochester Institute of Technology, I happened to spend a bit of time in Thomas Gosnell Hall. In it, there is a floor with tiles with various scientific things carved into them. I wasn't able to get photos of all the tiles but can someone tell me what these show? [4] [5] [6] [7] [8] Additionally, if you can find an explanation for the rest of them, I'd appreciate it. Thanks, Dismas|^(talk) 20:30, 9 June 2014 (UTC)

First looks like alchemical symbols or Astronomical symbols -- But are not-- see Jayron's answer below. Second one appears to be a likeness of a cloud chamber, compare e.g. image here [9]. Third seems to be a schematic of the Krebs cycle. Fourth might have something to do with dendritic growth or some branching process. Fifth should be easy for the chemists. SemanticMantis (talk) 20:48, 9 June 2014 (UTC)

(edit conflict) The first is the atomic symbols devised by John Dalton. The second looks like traces left by a particle accelerator collision of some sort. The third is the Krebs Cycle. I can't place the fourth picture. The fifth picture has some different things in it, so I am not sure what you are looking for. The white tiles at the upper right are the Schrödinger equation. The two black tiles show two different steroid molecules. The right one appears to be testosterone, while the left one is not one I can figure out. --Jayron32 20:54, 9 June 2014 (UTC)

The fourth one ("I think") is from a notebook sketch by Charles Darwin showing the tree of life - http://www.nhm.ac.uk/nature-online/evolution/tree-of-life/darwin-tree/ -- Finlay McWalterᚠTalk 21:07, 9 June 2014 (UTC)

I buy that. Funny, I was not familiar with that sketch, and ruled out "tree of life" because it is clearly not a binary tree (which is what we expect out of modern candidate trees). SemanticMantis (talk) 17:02, 10 June 2014 (UTC)

The dark tiles in the last one seem to show two different tautomers of the same steroid. --ColinFine (talk) 21:13, 9 June 2014 (UTC)

The second one is an image from a bubble chamber (a cousin of the cloud chamber). This specific trace (they're all different) is used quite widely, with many sources attributing it to CERN. CERN themselves simply says it's a "classic bubble chamber photograph. Millions of such interactions were studied during the 1960s and 1970s." They don't attribute it to a specific scientist, lab, or experiment. It may originate from Donald A. Glaser himself, but I can't find that out for sure. -- Finlay McWalterᚠTalk 21:21, 9 June 2014 (UTC)

Perhaps someone with journal access can pull Glaser's original paper (linked from his Wikipedia article) we may find that specific diagram there. -- Finlay McWalterᚠTalk 21:35, 9 June 2014 (UTC)

Thanks for the answers Finlay McWalter! I checked the 1952 Glaser paper. It is only one column of one page, and has no figures... SemanticMantis (talk) 16:59, 10 June 2014 (UTC)

To the left of the Schrödinger equation is Einstein's oft-quoted maxim "Everything should be made as simple as possible, but no simpler", the origin and accuracy of which Wikiquote debates. Left of that is (apparently) Einstein's famous mass–energy equivalence equation. -- Finlay McWalterᚠTalk 21:40, 9 June 2014 (UTC)

Thank you all for the answers! I didn't crop everything in camera as well as I normally would have. And the overhead lights were causing trouble trying to get a good angle on most of them. As for why there were so many things in the fifth picture, Jayron, I was trying to hurry before I got called away. I was only able to get these five shots before I had to go do something else. Thanks again! Dismas|^(talk) 01:16, 10 June 2014 (UTC)

Does knot theory have any application?

Besides making real knots? OsmanRF34 (talk) 20:46, 9 June 2014 (UTC)

First, knot theory is actually pretty useless for understanding real knots. It doesn't usually think about knot mechanics at all, and usually considers perfectly thin 1-dimensional filaments (technically embeddings of a circle) that are frictionless, and free to move about in any direction (i.e. no "binding"). When people need to know about knot performance, they usually test empirically, not based on theory. For example, the US coast guard has done tests for how knots effect breaking strength [10], a topic on which knot theory has nothing to say. It is true that one could do materials analysis of the forces within a knot under load -- but that is not the kind of thing that we would consider knot theory.

Now, although knot theory is pretty useless for real rope work, it has several applications. For instance, knot theory can be used to understand gene expression, and how DNA zips and unzips. See e.g. "DNA topology-mediated control of global gene expression in Escheria coli" [11]. We have some scant coverage at Writhe#Applications_in_DNA_topology, and Tangle_theory#Applications. Using the language of the last to wikilinks (+application) should get you some mileage on google scholar. SemanticMantis (talk) 21:04, 9 June 2014 (UTC)

There are applications of knot theory, in particular the Jones polynomial, to mathematical physics, in particular to quantum theory, according to this presentation by Ed Witten.[12] Red Act (talk) 22:05, 9 June 2014 (UTC)

It has been widely used in historic Ornament (art), in many cultures. In that sense knot theory may not be as new as modern mathematics suggest with its younger terminology. --Kharon (talk) 04:02, 10 June 2014 (UTC)

Absolutely. For better or worse, 'knot theory' these days usually means a branch of mathematics. However, 'theory of knots' is probably about as old as modern humans. In addition to ornamentation, theory of knots is how humans developed things like knitting, crochet, braiding, weaving, not to mention all the rope work involved with sailing. All very useful applications. The_Ashley_Book_of_Knots is probably the best starter reference for theory of real-world knots, and there are some very theoretical discussions and articles at the International Guild of Knot Tyers [13]. SemanticMantis (talk) 16:55, 10 June 2014 (UTC)