Wikipedia:Reference desk/Archives/Science/2010 September 11

= September 11 =

Rainbow Falls
Hello. I just made an article on Rainbow Falls, British Columbia. Could someone please find the coordinates of it? --The High Fin Sperm Whale 03:44, 11 September 2010 (UTC)


 * Looks to be at about 49°23'57"N 121°44'38"W, based on user-submitted information and photos on Google Earth. --  Tom N (tcncv) talk/contrib 04:30, 11 September 2010 (UTC)


 * So can someone add them to the article?--81.96.185.94 (talk) 08:37, 11 September 2010 (UTC)


 * BCGNIS search is useful for such things, although the coordinates are rounded to minutes. There are five Rainbow Falls in British Columbia, this one is, I believe. Pfly (talk) 10:30, 11 September 2010 (UTC)

Google maps is your friend Quadrupedaldiprotodont (talk) 14:15, 11 September 2010 (UTC)

Sending nuclear waste to space
I recently watched a TV documentary about how difficult it is to get rid of nuclear waste. So I came to think, what's stopping us from sending it out to space in unmanned throwaway rockets? The only thing that comes to my mind is that it would be far too expensive, but are there other reasons too? J I P &#124; Talk 09:54, 11 September 2010 (UTC)
 * Impracticality and risk, according to our article's subsection on space disposal. ---Sluzzelin talk  10:01, 11 September 2010 (UTC)


 * There are two issues:
 * 1. We have a lot of nuclear waste from the space disposal perspective (not necessarily in the "how much waste per unit of energy" perspective). As in 62,500 metric tons of high level waste for the US alone, which is what we are really worried about. (Low-Level Waste is present in far greater volumes, but loses most of its radioactivity over the course of 100 years or so, which is a lot easier to secure from a technical point of view.)
 * 2. Sending things into space has a reasonably high accident rate, ranging from some 5%-15% or so depending on your launch vehicle.
 * When you combine the two of these, it suddenly doesn't seem like a great idea. To make a significant dent in the waste problem, you have to send up a lot of rockets. How many? If we take the listed payload of a Saturn V, which is huge, it means you would need some 530 launches to get our existing high level waste inventory into just low Earth orbit, without any shielding whatsoever. If we use anything more economical/efficient than that, the number of launches goes up dramatically! That means that at least one of those is probably going to blow up when it is being launched — even if you get the failure rate down to something like 1% (in other words, 99% success), you're still talking about at least 5 major environmental catastrophes, but probably a lot more (since that number of total launches is extremely optimistic and doesn't take into account the fact that the payloads of modern rockets are a lot less than the Saturn V, and the fact that a huge bulk of your mass on each strip would be shielding, even in a minimum-shielding situation). More realistically you're talking about dozens of disasters. That means you're now spreading nuclear waste into the surrounding area. Not good. Of course, you could put some heavy duty shielding in place, right? But now you've just decreased the amount of waste you can send on each trip, meaning you have even more trips, at greater expense.
 * It's not economical and it's not safe. You're better off, in terms of the tradeoff of risk and expense, just dumping it into a deep sea trench, if you're going to consider doing that.
 * In any case, the real difficulty in getting rid of waste is mostly a political problem, only in a small degree a technical problem. Or, put another way, the technical problem is the political problem. In the US, for example, the law requires the government be able to certify that absolutely no people in the next 10,000 years or so (at the minimum) will ever have a negative health effect due to this waste. You basically cannot do that, not just with nuclear waste, but anything. It's an absurd standard that we don't hold any other toxic or hazardous substance to, because it's completely impossible to satisfy from a technical point of view, because of the time scales involved. If we were a bit less strict in our standards — that all that was to be avoided was an absolutely worst-case-scenario, and that the waste would be buried somewhere where its being disturbed was unlikely — it wouldn't be such a difficult technical problem.
 * If there were non-rocket means of getting things into space (e.g. a space elevator), the question might be on the table, but we don't have those yet and it's not clear what their actual performance would be until then. --Mr.98 (talk) 12:12, 11 September 2010 (UTC)


 * A further issue is that what's now seen as waste might later be seen as a valuable energy source, so sending it beyond easy retrieval isn't a great idea. I think I came across this point somewhere in Sir Arthur C. Clarke's nonfiction writings, or maybe it was Isaac Asimov's, but I can't cite the specific book.  --Anonymous, 21:30 UTC, September 11, 2010.
 * Sounds more like Larry Niven or Jerry Pournelle. --Trovatore (talk) 02:03, 12 September 2010 (UTC)
 * Well, it's certainly the case that you could get more energy out of the transuranic waste by doing nuclear reprocessing, which is currently not done in the US for political/safeguards reasons. Doing so would also reduce the volume of waste significantly. Other than that, probably not. Waste does generate heat but my understanding is that the energy is not efficient enough for practical usage, once you add in all of the radiation protection issues. --Mr.98 (talk) 23:45, 11 September 2010 (UTC)


 * I've heard of Sodium_reactors designed make energy by `burning' what is currently considered waste, but our I don't see mention of this in the article.SemanticMantis (talk) 01:37, 12 September 2010 (UTC)


 * Well, it does say they'd use a closed fuel cycle with lots of reprocessing, so that is probably what is meant. You can't just put raw waste into a reactor; it won't fission correctly (there are fission products that have a "poisoning" effect on the reaction), and the radioactivity is too high for anything but very circumspect handling. But if you strip out the left over uranium and plutonium from the waste, you can use that. That's what reprocessing does. Again, in the US, in particular, we treat spent fuel as "waste." We could treat it as feed for reprocessing. We stopped doing that in the 1970s because of fears that it would create a large volume of weapons-usable plutonium that would be hard to account for (or, put another way, if you have a large reprocessing plant, like the Rokkasho Reprocessing Plant in Japan, you will inevitably have some % of fissile material loss unaccounted for, which makes an ideal situation if you were trying to steal enough fissile material for a bomb). --Mr.98 (talk) 12:38, 12 September 2010 (UTC)


 * on your no-injury-in-10,000-years claim? Comet Tuttle (talk) 12:51, 12 September 2010 (UTC)


 * Well, I did simplify it a bit, because the actual regulatory requirements are complicated (and in fact, which regulatory requirement matters is complicated, because there are at least three agencies with possible jurisdiction over this—EPA, NRC, and DOE). But it was in the late 1970s that the EPA set a requirement that any "reasonably foreseeable" release should not exceed "one chance in a hundred in 10,000 years", and that any major accident should be "virtually impossible" and thus not exceed one chance in a million over 10,000 years. The NRC argued that this was basically an impossible level of precision to require over that time scale. In 2004, though, the US Court of Appeals ruled that the EPA was required by law to set radiation standards not just for 10,000 years but for a million (!) years. In 2008 the EPA came up with rather specific standards for exactly what the radiation release at a place like Yucca Mountain must be for the next million years, and the NRC/DOE has to be able to certify that any storage method can meet them. Long discussion of some of these technical rulings with an emphasis on the recent ones here: Anyway, as you can probably tell, I think this is all kind of nuts, as if we can predict with any reliability anything on Earth for the next million years, much less something as complicated as the long-term disposition of radioactive materials. It's a regulatory nightmare. Anyway, the original concern regarding 10,000 years (which is already crazy, much less a million years), came from a EPA estimate that the Yucca Mountain site would cause between 100-1000 fatal cancers over 10,000 years (that is, one fatal cancer every 10-100 years), which is somewhat what I was referring to before in a shorthand way. My citation for all of this are notes I took awhile back on J. Samuel Walker's The Road to Yucca Mountain, chapters 5 and 8. --Mr.98 (talk) 14:35, 12 September 2010 (UTC)

contradiction in electromagnetism
I have one doubt. When two similar charges are kept at a distance and if our reference frame is not moving and charges too are not moving then they repel each other. If our reference frame starts moving lets say backward from charges with some speed, then we see that charges are going away with same speed. Because charges are moving, they will create magnetic field and we should see that they attract each other (because they are moving in the same direction with respect to us.) According to me this is a contradiction. Just because of changing our reference frame how can phenomena change? Change in reference frame should not change the phenomena. —Preceding unsigned comment added by Ptamhane (talk • contribs) 10:01, 11 September 2010 (UTC)
 * For a charge to induce a magnetic field, doesn't it have to be moving through a conductor? Not just a "frame of reference"? Vespine (talk) 11:18, 11 September 2010 (UTC)
 * No, fundamentally magnetism is a relativistic effect, the electric field is (partially) transformed into a magnetic field by the moving frame. The effect is easier to understand if two lines of charges are considered instead of two isolated charges.  The distance between the charges in each line will be reativistically foreshortened in a moving frame.  Two lines moving in opposite directions will measure (in a frame moving with one line) the distance between charges in the other line as being less, and consequently a greater charge density leading to a greater repulsion.  Two lines moving in the same direction will have less repulsion, as observed by a frame at rest.  These adjsutments to the electrostatic force are the root of magnetic forces.  Sp in ni  ng  Spark  13:06, 11 September 2010 (UTC)
 * You just made my brain hurt.. Vespine (talk) 13:28, 11 September 2010 (UTC)
 * Not to contradict any of that (which I actually don't understand, I'm afraid), but it might help to add that electromagnetism is governed by Maxwell's equations. When Einstein developed Special Relativity, his primary motivation was to find a space-time transformation that kept Maxwell's equations valid in moving reference frames.  They are not valid in moving frames in Newtonian mechanics, though. Looie496 (talk) 18:21, 11 September 2010 (UTC)
 * See also, Liénard–Wiechert potential, which describes the magnetic field of moving charges; and Covariant formulation of classical electromagnetism, which describes the way that the Maxwell Equations bridge the gap between classical and relativistic mechanics. Nimur (talk) 09:01, 12 September 2010 (UTC)
 * When charge line A is moving in the same direction parallel to charge line B, they have relatively normal repulsion, but when the lines are moving parallel in opposite directions...the "charges" in line B relative to line A (observer) experience a form of electromagnetic redshift, so that the line B relative to itself undergoes length contraction, causing both lines to have a stronger "repulsive" force relative to each other, making the repulsion stronger? Is this close to the description above? ~ A H  1 (TCU) 00:45, 12 September 2010 (UTC)

Horseshoe Crabs
The article on horseshoe crabs says that they are over-harvested. But who harvests horseshoe crabs and for what? —Preceding unsigned comment added by 69.120.0.81 (talk) 12:04, 11 September 2010 (UTC)
 * Ummm, Your question is answered in the very same sentence.. I'll give you a hint: East coast of North America and fertilizer and bait. Vespine (talk) 12:32, 11 September 2010 (UTC)
 * Actually the answer is also partly in the Blood section. It turns out that horseshoe crabs have very weird blood that contains a unique substance that is a very sensitive detector of bacterial contamination, which makes it extremely valuable to the biotech industry.  There was an episode of the PBS show Nature devoted to this in 2008, which can be viewed online. Looie496 (talk) 18:14, 11 September 2010 (UTC)
 * Could a knowledgeable editor add such relevant material to the Blood section of the article? That section is currently a little short and vague.  Comet Tuttle (talk) 12:45, 12 September 2010 (UTC)
 * There is some referenced info in the article on limulus amebocyte lysate. ---Sluzzelin talk  12:53, 12 September 2010 (UTC)

Helium shortage
If we're running out of helium, why can't we make some more by taking radioactives (and we have plenty, via nuclear waste), and then putting them in an atmosphere. It seems like they would spit off enough alpha particles for this to be useful. Alpha particles + other stuff = slightly ionized other stuff + helium. —Preceding unsigned comment added by 69.120.0.81 (talk) 12:09, 11 September 2010 (UTC)
 * One problem is that the most radioactive bits of nuclear waste are not alpha emittors. Another is the scale that would need to work on. World helium production in 2009 was about 29,000 tonnes, or 7.23 gigamoles. As helium-4 has relative atomic mass 50–60 times less than that of most alpha-emitting nuclides, you would need 1–1½ million tonnes of alpha-emitting radioactive waste to decay each year to supply the world's helium consumption. Physchim62 (talk) 12:48, 11 September 2010 (UTC)

ARE we running out of Helium? The article says "Helium is the second ... most abundant [element] in the observable universe". Also it doesn't burn, so how is it being used up then?? Quadrupedaldiprotodont (talk) 14:12, 11 September 2010 (UTC)
 * It's not that we're running out, it's that we cant produce it as quickly as we use it up. While it is abundant in the universe, it's not certainly not freely abundant on earth, it only makes 0.000524% of our atmosphere. Vespine (talk) 14:18, 11 September 2010 (UTC)
 * If we were using the helium from the atmosphere, there wouldn't be a supply problem, but we're not: we're using helium which has accumulated in natural gas deposits, which is much much cheaper to separate. What we're running out of is cheap helium. Still, as the price rises, helium recycling becomes more and more cost effective and helium will stop being used for applications where argon can do the job just as well. I think we will see some pretty efficient helium recycling long before we see significant quantities being extracted from the atmosphere. Physchim62 (talk) 14:51, 11 September 2010 (UTC)
 * Unfortunately the sell-down of the Strategic Helium Reserve is artificially depressing the price. Hopefully the market will anticipate the end and cushion the blow.  But helium is so hard to keep as inventory that I don't know that it will. --Trovatore (talk) 04:10, 12 September 2010 (UTC)
 * ... ah, apparently it's called the National Helium Reserve. I was mixing up the name with the Strategic Petroleum Reserve. --Trovatore (talk) 04:12, 12 September 2010 (UTC)
 * This story did the rounds recently (reprinted in numerous other papers) as did other articles  apparently partially a result of a? talk at the Nobel Laureate Lectures at Lindau which could be what got the OP thinking. BTW, as mentioned in our article helium which is released to our atmosphere is eventually lost to space in what's considered a relatively fast time. The current low level in the atmosphere is the result of the natural balance of helium arising from decay and helium that escapes. This is evidentally something that gives YEC wet dreams because they claim the level proves the earth is young. Nil Einne (talk) 06:44, 12 September 2010 (UTC)
 * Yeah, we are running out of cheap Helium. Jupiter's atmosphere is 10% helium, so if money was no object, we could get all the helium we wanted.  Googlemeister (talk) 13:19, 13 September 2010 (UTC)

Lonely
What is the science behind lonely people? Why are some people socially retarded and lonely, unable to get a girl/boy friend? Is it evolutionary? —Preceding unsigned comment added by Friend4u772 (talk • contribs) 13:26, 11 September 2010 (UTC)
 * This is covered at Loneliness Regards, --— Cyclonenim | Chat 13:29, 11 September 2010 (UTC)
 * See social alienation and unrequited love. ~ A H  1 (TCU) 00:15, 12 September 2010 (UTC)


 * Personal attack removed Nil Einne (talk) 09:28, 12 September 2010 (UTC)
 * "Personal experience" isn't particularity helpful when the OP asked for scientific reasons. 79.163.124.125 (talk) 11:11, 12 September 2010 (UTC)
 * See Recluse, isolation, solitude, and seclusion.Smallman12q (talk) 14:19, 12 September 2010 (UTC)
 * Personal attack removed Nil Einne (talk) 19:26, 12 September 2010 (UTC)
 * Is that a personal attack?Smallman12q (talk) 23:48, 12 September 2010 (UTC)
 * Whatever it is, it's pointless troll feeding and not helpful to the OP. 99.18.82.80 (talk) 23:51, 12 September 2010 (UTC)
 * Those comments by Nil Einne are completely inappropriate, I think they deserve a caution. Vespine (talk) 01:22, 13 September 2010 (UTC)
 * Support. "Caution, Nil!"  Wiki Dao   (talk)  01:52, 13 September 2010 (UTC)


 * Struck posts not relevant to answering question. Franamax (talk) 02:06, 13 September 2010 (UTC)

Insulating magnets
What are the possible ways/tricks to insulate magnets? One way I've been thinking about is producing an opposite magnetic field but not sure if it works. --Email4mobile (talk) 13:39, 11 September 2010 (UTC)
 * If by insulating magnets, you mean shielding its magnetic field, the most common way would be to use high permeability materials as a shield. See for example Mu-metal. --Polaron | Talk 13:57, 11 September 2010 (UTC)
 * Also check out Electromagnetic shielding. 88.112.56.9 (talk) 14:00, 11 September 2010 (UTC)

Perhaps coat it in thick cement Quadrupedaldiprotodont (talk) 14:09, 11 September 2010 (UTC)
 * Concrete has a fairly low magnetic permeability, a property that makes it a poor shielding material. "Thick" is helpful because a magnetic field weakens as you get far from it, but the concrete itself is no more effective than air, and much less effective than steel or many other common shielding materials. DMacks (talk) 18:39, 11 September 2010 (UTC)

Lifting heavy weights = nerve failure
I used to do a lot of weightlifting when I was in my teens (about 20 years ago.. so this isn't a request for medical advice lol) and I once did a phase of lifting very heavy weights. It was more powerlifting really, low rep compound exercises at near my max lift weight, I think it was based on doing 3 sets of 3 reps at near the maximum weight one could lift to build up strength as quickly as possible (rather than muscle size). Not long into the training I did a session when I suddenly couldn't grip the barbell properly let alone lift it. A guy at the gym explained what it was but I'm trying to remember the exact name for it. I think it's something to do with overloading the nerves that control your muscles. And it's temporary, whatever the cause you recover quickly in the same way that lactic acid causes an athlete to stop to recover before starting again. Can anybody point me to a link please? 84.93.187.219 (talk) 18:18, 11 September 2010 (UTC)
 * You could try looking into the articles on Paresthesia or Hypoesthesia or Obdormition (the second and third are more of stubs). The Somatosensory system is in charge of sensations like this, so you may find something there.  Better yet, you should talk with a medical professional; perhaps an athletic trainer given the nature of your question, or perhaps a doctor.  If something unexpected happens to your body in this way, you shouldn't take the advice of a random dude at the gym, or random dudes at the internet.  Ask, in person, someone who has the actual training and certification to answer intelligently.  -- Jayron  32  04:15, 12 September 2010 (UTC)
 * I appreciate the links, they didn't answer my question though. To be clear I'm not asking for advice about the condition, I want to remember what the condition is called. The guy who explained what had happened knew what he was talking about and I researched it at the time, it had a specific name. You know when you have something that you're trying to remember and it really winds you up? This is one of those times! Spoonfulsofsheep (talk) 16:26, 12 September 2010 (UTC)

I think I'm close to an answer with help from wikipedians. It's related to central nervous and peripheral nervous system fatigue. I still haven't found the specific term tho! 87.115.9.84 (talk) 17:05, 12 September 2010 (UTC)
 * Fasciculation? Physchim62 (talk) 19:40, 12 September 2010 (UTC)
 * Ah, it's not fasciculation (probably the opposite actually) but it's related to what I was thinking and put me in the right direction thanks! It's a bit more complex than I remember from 20 years ago which may be why I couldn't find it via google. Wikipedia touches on it in Weakness, specifically 'For extremely powerful contractions that are close to the upper limit of a muscle's ability to generate force, nervous fatigue can be a limiting factor in untrained individuals. In novice strength trainers, the muscle's ability to generate force is most strongly limited by nerve’s ability to sustain a high-frequency signal. After a period of maximum contraction, the nerve’s signal reduces in frequency and the force generated by the contraction diminishes. There is no sensation of pain or discomfort, the muscle appears to simply ‘stop listening’ and gradually cease to move, often going backwards'. Tx all! Spoonfulsofsheep (talk) 20:51, 12 September 2010 (UTC)
 * That's a little scary! Can it happen suddenly, as in the weight could nearly free-fall on you?  I frequently work with up to 200 lbs or so without a spot (I leave the collars off so that I can dump the weight if necessary). --Trovatore (talk) 22:07, 12 September 2010 (UTC)
 * You see something very similar to "weights in free-fall" in many weight-lifting competitions... Physchim62 (talk) 23:22, 12 September 2010 (UTC)
 * Barring an underlying condition the answer is no, but you obviously shouldn't use weights without a spotter! This condition is specifically about lifting something close to your max weight in the 1-3 rep range (in rapid succession) for strength training that causes the nerve signal to the muscle to wear out before the actual muscle is fatigued. If you're doing typical weight training or bodybuilding there will be a number of other factors that stop you exercising other than nervous fatigue, 'muscle burn' being an obvious contender. 87.115.119.136 (talk) 23:33, 12 September 2010 (UTC)

Orbital overlap
We don't seem to have an article on this rather fundamental concept in chemical bonding. Or do we? How would you describe it non-mathematically? Is is still as relevant as it used to be, now with the rise in density functional theory methods? Physchim62 (talk) 19:23, 11 September 2010 (UTC)
 * I might be wrong, chemistry isn't my strong point, but molecular orbital diagram seems to discuss a little about this. Might be worth checking out. Regards, --— Cyclonenim | Chat 22:43, 11 September 2010 (UTC)
 * You may also be interested in valence shell. ~ A H  1 (TCU) 00:10, 12 September 2010 (UTC)
 * The orbitals overlap by hybridizing which is part of valence bond theory.--72.152.236.190 (talk) 01:23, 12 September 2010 (UTC)
 * The statistical mechanics of Schroedinger wave interactions, charge boundary interactions, and phase boundary interactions also pertain to orbital hybridization. 208.54.5.55 (talk) 03:40, 12 September 2010 (UTC)

Applications for chemicals
Does anyone have any good references for finding the applications of a chemical? For example, I can see that thiodiglycol is used as a solvent, but I'd like to learn about ALL (or more!) of the applications for that chemical. Where would I look for those applications? Clearchemistry (talk) 21:47, 11 September 2010 (UTC)clearchemistry


 * can you narrow your quest down. What do you want to know for? For instance there are books like but does this address your thirst?--Aspro (talk) 22:11, 11 September 2010 (UTC)
 * What do you mean? The OP has clearly stated what they want: information about the applications of thiodiglycol. I presume you've read our article on the chemical. The main use I find by Google searching is it's use as a precursor to mustard gas, though I doubt (and hope!) you won't be using it for that purpose. This link has a nice section on it's other applications and properties. Regards, --— Cyclonenim | Chat 22:41, 11 September 2010 (UTC)
 * Perhaps not clear enough. It looks to me that the question-asker is looking for a general resource to go with this sort of question. The Thiodiglycol is just an example. APL (talk) 07:59, 12 September 2010 (UTC)
 * Well mustard compounds can be used as anticancer drugs...no? John Riemann Soong (talk) 03:41, 12 September 2010 (UTC)