Wikipedia:Reference desk/Archives/Science/2013 February 16

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.

February 16

One Kidney Giving Out

If one of someone's kidneys gives out but the person's other kidney is still working, would the person need to remove the failed kidney from his body in order to continue to survive or how would that work? Also, one kidney can fail while another would continue to function properly, correct? Thank you very much and sorry if this is a stupid question. Futurist110 (talk) 00:11, 16 February 2013 (UTC)

It all depends on why one kidney failed; if it's cancer, then it should be removed (or irradiated or otherwise dealt with). If not, it may just atrophy without causing any further problems. And yes, one kidney can continue to function alone, although a diet and habits that take it easy on the remaining kidney would be a good idea. StuRat (talk) 00:30, 16 February 2013 (UTC)

StuRat's answer is, unfortunately, a typical StuRat off-the-cuff answer. He's right of course about a cancerous kidney - as cancer can spread. However, as with muscles and most other things in the body, kidneys grow to a size able to take the load. If you lose one kidney, the other one increases in size and there is more or less no permanent impact. There is no need for a special diet or habits. See http://www.kidney.org/atoz/content/onekidney.cfm. The main impact is that a urinary tract infection that impacts on the kidney will have a more serious impact, but such infections are fairly rare, especially in men. Sulpha antibiotics, which tend to cause scaring in the urinary tract, have a higher impact in people with only one kidney. No doubt StuRat will come back, he usually does, with some abuse and/or some website that almost but not quite supports that a special diet is indicated. Wickwack 58.164.228.62 (talk) 03:48, 16 February 2013 (UTC)

Yea, like this source: "You simply need to make healthy choices, including fruits, vegetables, grains, and low-fat dairy foods. Limit your daily salt (sodium) intake to 2,000 milligrams or less if you already have high blood pressure. Reading nutrition labels on packaged foods to learn how much sodium is in one serving and keeping a sodium diary can help. Limit alcohol and caffeine intake as well. Avoid high-protein diets. Protein breaks down into the waste materials that the kidneys must remove, so excessive protein puts an extra burden on the kidneys. Eating moderate amounts of protein is still important for proper nutrition. A dietitian can help you find the right amount of protein in your diet." [1]. Now for your abuse: You're the one who doesn't know what he's talking about, as usual. StuRat (talk) 04:18, 16 February 2013 (UTC)

You left out the first sentence in that section (Eating sensibly): "Having a single kidney does not mean you have to follow a special diet". And you didn't mention that the 2 grams of salt and the rest of it is just about standard advice given to every one these days, regardless of number of kidneys. Wickwack 124.182.162.210 (talk) 05:00, 16 February 2013 (UTC)

The moderating protein intake isn't a normal recommendation. Also, I didn't say a special diet was required, that was you. I just said "a diet and habits that take it easy on the remaining kidney would be a good idea". This is using "diet" to mean "what you eat", not "a crash weight loss plan" or any other meaning. StuRat (talk) 05:45, 16 February 2013 (UTC)

Consuming an excessive fraction of protein is not a particularly good idea for anyone, two kidneys or not, and is standard advice ever since the Swedish Govt devised the well-known "food pyramid" in 1974 (which advises protein consumption between 10 and 15% measured by calorific content), and was inherent dietry advice for the general population well before 1974 - I remember being taught at school 60 years ago to eat from a balance of 5 food groups (Most govts now advise on the basis of 7 groups). The essense of the advice from the various websites provided here by myself, yourself, and others can be summed up as follows: No special diet is needed, however a bad diet may carry greater risk for a person with only one kidney. If that's what you meant, why didn't you say so? You said "a diet and habits that take it easy on the the remaining kidney would be a good idea." Which means a special diet. Why didn't you say no special diet needed? Because you posted off-the-cuff without thinking or checking, as usual. Wickwack 121.221.31.66 (talk) 09:48, 17 February 2013 (UTC)

It does not mean that, you just look for any possible way to attack me, even if it means intentionally misinterpreting whatever I say. StuRat (talk) 03:35, 18 February 2013 (UTC)

As our article Kidney transplantation says, when someone receives a new kidney his or her own kidneys are not removed. There seems to be no drawback to keeping the non-functional kidneys, and an increased risk by removing them. Also, as I understand it, sometimes their own kidneys still have some function and you want to keep that if possible. Sjö (talk) 08:21, 16 February 2013 (UTC)

---

Information about High protein, high fat, low carbohydrate (Atkins) diets and normal (dual) kidneys:

http://abcnews.go.com/blogs/health/2012/06/01/high-protein-low-carb-diet-safe-for-kidneys/

http://news.yahoo.com/atkins-type-diets-look-kidney-friendly-study-210610591.html

http://health.usnews.com/health-news/news/articles/2012/05/31/atkins-type-diets-look-kidney-friendly-study

We know that some sorts of kidney disease require a low protein diet, so the person with one kidney should ask his/her physician if whatever was wrong with the first one is also wrong with the second one.

We also know that obesity is bad for your kidneys, so if the diet helps you to lose weight that is a plus.

I cannot find any studies on high-protein diets and single kidneys. Some doctors advise avoiding a high-protein diets with a single kidney, but the question is whether this is backed up by studies or just being cautious. --Guy Macon (talk) 09:00, 16 February 2013 (UTC)

This is all pure OR. My father received a kick to one of his kidneys while playing rugby, which resulted in him missing 18 months schooling and the kidney itself failing completely. That was not known until 40 years later, when he was hospitalised for severe hypertension. His kidney function was assessed as 20% in the one remaining functional kidney. He didn't need any special diet, he was advised to moderate his salt intake (which he ignored) and was put on medication which he took for the remaining 30 years of his life. So the answer to the OP's questions are no, you don't need to have a non-functional kidney removed: in fact, you can live for many years without even knowing you have a non-functional kidney. I'll have a trawl of a website to confirm with references for you. --TammyMoet (talk) 13:17, 16 February 2013 (UTC) Here's a webpage that answers your questions. --TammyMoet (talk) 13:22, 16 February 2013 (UTC)

What do these terms mean?

On the Doctor Who Restoration Team website, there are repeated references to "tramline damage", "off-lock"s, and "phosphor hole"s. What do these terms mean? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 00:20, 16 February 2013 (UTC)

• Tramline damage is simply long scrapes down the film or tape caused by something scratching the tape is it moves past. [2]
• Video tape, and analog video signals in general, contains synchronisation information about the end of a line and the end of the whole screen (it's much more complicated than that, but that's the idea). A player uses that information to keep its own clock in line with the tape. If the tape is damaged or degraded, that synchronisation information can be corrupted. This causes the player to lose an accurate idea of where the video has got to; it has lost "lock". When this happens the picture rolls up or down or breaks up entirely. See Analog television#Synchronization
• This posting (the bottom one) explains a phosphor hole.

-- Finlay McWalterჷTalk 01:04, 16 February 2013 (UTC)

So when it loses lock, the player simply scribbles lines across the screen in all the wrong places? Whoop whoop pull up ^{Bitching Betty | Averted crashes} 02:28, 16 February 2013 (UTC)

Assuming you are familiar with that site, are they bringing back any lost episodes, or just restoring known ones? μηδείς (talk) 02:37, 16 February 2013 (UTC)

See Doctor Who missing episodes and Doctor Who Restoration Team. -- Finlay McWalterჷTalk 02:48, 16 February 2013 (UTC)

Thanks. I was familiar with the first article. It would be interesting to see one of the improved episodes. μηδείς (talk) 03:50, 16 February 2013 (UTC)

If you've watched any dvds of the first seven doctors' adventures, then you already have. 86.163.209.18 (talk) 09:33, 16 February 2013 (UTC)

If it loses vertical lock, the picture rolls up (or down) (with stuff that goes off one margin coming on at the other) - usually there's a wide blanking gap (a black strip) which sometimes contains flashing garbage. If you ever had to tune an old TV with a bad antenna you'd recognise this. Losing horizontal lock is worse; depending on the system, and the kind of degradation, the picture might slide sideways, go all sideways-diagonal-ish, or just turn into a horrible cascade of little horizontal slices of picture that jerk about on the screen. -- Finlay McWalterჷTalk 02:46, 16 February 2013 (UTC)

How many isomers does 1024-ane have(both including and excluding stereoisomers)?

Already checked the OEIS record, but that is still too complicated for me to understand. I just want to add this information to a humor page.--Inspector (talk) 01:37, 16 February 2013 (UTC)

It is too long ago, but I think I remember that only if you exlude ring systems which you obviously not do a solution with a relative easy algorythm is possible with ring systems they said it is very complicated.--Stone (talk) 10:24, 17 February 2013 (UTC)

Let's s say there is no ring system. What does the formula expanded look like?--Inspector (talk) 12:12, 17 February 2013 (UTC)

If a closed formula were known, I'd expect OEIS to show it. —Tamfang (talk) 07:02, 19 December 2013 (UTC)

Conservation of energy

Consider a workman using a heavy implement such as an axe or sledgehammer to do irreversible work such as splitting a block of wood, breaking a rock or flattening an empty beverage can. The workman gives the implement a large amount of potential energy by raising it above his head. He then lets it fall and the potential energy is converted to kinetic energy. After the implement has struck the wood, rock or beverage can, all mechanical energy has disappeared. It is not possible to recover the lost mechanical energy by re-joining the block of wood, re-assembling the rock or stretching the flattened beverage can. Has energy been conserved? If so, to what form of energy has the mechanical energy been converted? How do we explain the validity of the law of conservation of energy in this situation? Dolphin (t) 03:17, 16 February 2013 (UTC)

Is this a homework question? Someguy1221 (talk) 03:27, 16 February 2013 (UTC)

No, it isn't a homework question. I know the answer ("Yes, energy is conserved") but I am asking it here to see how different Users go about explaining it. Our article Conservation of energy doesn't address the situation. Dolphin (t) 03:32, 16 February 2013 (UTC)

Wait a sec, you claim on your userpage to have a college degree in engineering...Someguy1221 (talk) 03:28, 16 February 2013 (UTC)

I would like to think that only someone with a college degree in physics or engineering would be able to formulate this question. I think it would be a good question in a physics exam. Dolphin (t) 03:41, 16 February 2013 (UTC)

Of course I can tell you where the energy is going, but I do not have the competence in physics to really explain why the energy cannot be got back without waving my hands rather furiously. I was hoping to build an explanation around conservative vs. non-conservative forces, but our article seems to go into no detail on the practical implications of a force being one or the other. Someguy1221 (talk) 03:49, 16 February 2013 (UTC)

Most literature, including Conservation of energy, focusses all attention on converting energy from one form to another. A small amount of literature also talks about doing reversible work such as dropping an object onto a spring so that the object rebounds to its original height. All the literature (that I am aware of) is silent on the subject of doing irreversible work. Dolphin (t) 03:54, 16 February 2013 (UTC)

(ec) Ignore the energy lost because a human is an inefficient chemically-driven thermodynamic machine. (That is easy to understand in a hand-waving way, but it's harder to explain specifically unless we want to dive into the depths of biochemistry and metabolism). Consider only the irreversible energy-transfer related to the cutting of a material. Plastic deformation is the opposite of elastic deformation, in that it is irreversible. In the microscopic case, if we really really really zoom in on the act of cutting a material, we see that the act of cutting performs work on the material, in the form of both elastic- and plastic- deformation. Both types of work on a material can result in temperature change; temperature change can mean that additional heat energy will be lost via conduction and radiation, and will not be recoverable (for the usual reasons). Now - why are some materials subject to plastic (irreversible) deformation; and others are not? Because the molecules are arranged differently. This is a game of statistics calculated among ensembles of particles. For some materials, there are lots and lots and lots of local minima in the energy for lots of arrangements of molecules, so by proverbially "shaking up the lattice" you might find a different mechanical layout that is stable. For other molecule arrangements, there is one clearly-lowest-energy arrangement, and if you deviate from that arrangement, the material's constituent particles all try to go back towards its optimal arrangement. The exact nature of these materials is well-studied; we can elaborate on different metallurgies and ductile deformations and brittle failures and so forth; but, you're an aeronautical engineer! This should have been covered ad nauseum in a materials engineering class! Nimur (talk) 03:58, 16 February 2013 (UTC)

(ec) Just about any undergrad uni physics textbook has this question or something just like it in the student exercises section (Mine has the workman driving a nail into wood), so I am a bit skeptical about the clained college degree too. The answer of course, it that the potential energy given to the hammer by the workman when he lifts it is conveted to kinetic energy, which, when the can is flattened / nail driven in / wood split or whatever, is converted via plastic deformation / friction / whatever, as respectively applicable, into heat. With a bit of "spherical cow" simplification and a value for specific heat of the can / nail /wood you can calculate the temperature rise in the can / nail/ wood. Wickwack 121.221.89.248 (talk) 04:00, 16 February 2013 (UTC)

A lot of the energy goes into producing sound and heat. The sound pretty soon turns into heat too. The heat can't be collected together again and put back into moving the axe because of the nature of entropy. SteveBaker (talk)

Not much will go into sound though. Almost all will go directly into heat. I can show why with some calcs, but doing so will reveal too much. I think this is a homework question (because in undergrad physics it is a common homework question), so I won't show the math, unless the OP comes back and shows he's made an honest go at it, and got stuck. You don't need to understand the concept of entropy to do this one. Wickwack 121.215.77.163 (talk) 09:58, 16 February 2013 (UTC)

I like SteveBaker's explanation, particularly his reminder that entropy is relevant in this situation. I agree with Wickwack that an understanding of conservation of energy comes before an understanding of entropy, but despite that, I think I will find some of the concepts from thermodynamics to be helpful. For example, when flattening an empty beverage can the work done on the beverage can will equal the increase in internal energy of the material comprising the can. It may all go to an increase in temperature of the material, or alternatively work hardening of the deformed metal may also represent an increase in internal energy, leading to less of an increase in temperature. I will think about it overnight.Dolphin (t) 12:10, 16 February 2013 (UTC)

Agreed; the reference to the second law makes the whole thing make more sense. Thanks Steve! Rutebega (talk) 03:43, 20 February 2013 (UTC)

I am proposing some initial changes to Conservation of energy. See the Talk page - diff and please join in the discussion. I have also made some changes to Mechanical energy – diff 1 and diff 2. Dolphin (t) 02:09, 19 February 2013 (UTC)

About orbits of planets, electrons and other objects in dimensions higher than 3

Is is true that there can be no stable orbits for dimensions higher than 3, because the strength of gravitational and electrical field decreases more rapidly than in 3 dimensions, (e.g in 4 dimensional space the gravitational force is inversely proportional to the cube of distance)?--Inspector (talk) 14:56, 16 February 2013 (UTC)

The article Newton's theorem of revolving orbits has a short discussion of other central force laws like the inverse cubic. Actually magnets at some distance apart attract with an overall inverse cubic force so one could try this in space with a couple of magnets. Well actually they'd have to keep the same orientation, if one is rotating it goes down quite a bit faster. Dmcq (talk) 01:23, 17 February 2013 (UTC)

Next glacial period and survival of civilization

The earth is currently in an interglacial period (Holocene interglacial) since the last 12000 years. The next glacial period will start 50000 years later. I'm interested in knowing whether the global climate in a glacial period suitable for normal functioning of civilization (agriculture, public health, industry, transport etc). Will the next glacial period affect human activities in certain regions or all over the world (to the extent that human populations from one region have to migrate to other or die out)? --PlanetEditor (talk) 15:24, 16 February 2013 (UTC)

If what we've been told so far is true, natural cooling and warming cycles like this happen so slowly that we could "migrate" the necessary distance by each generation being born in a hospital ten miles further north or south (as necessary). My mathematics may be a little off, but you get the idea - if a climate change takes thousands of years, it's really not quick enough for human civilisation to really care.

Or, of course, we might be experts on anthropogenic climate change by then, and be able to stave off ice ages by increasing our CO2 output by some amount. --Demiurge1000 (talk) 15:33, 16 February 2013 (UTC)

Agreed. Our technology then will be so far advanced, that we shouldn't worry about it. For example, we may also have fusion reactors working then, providing the cheap energy needed for hydroponics. StuRat (talk) 17:29, 16 February 2013 (UTC)

• First, there's no prediction that the next glacial period will begin in 50,000 years--the record is chaotic and there have been interglacials that have lasted less time than the one were'in. Second, there's evidence the change may be rather abrupt, on the order of a decade, not centuries. Migration on that scale would be rather traumatic. Third, there's absolutely no guarantee of progress, Rome fell and something like a luddite caliphate is always possible. But lastly, there's no reason to believe humanity wouldn't survive in the lower latitudes no matter what. μηδείς (talk) 20:17, 16 February 2013 (UTC)

• There have been short-term, localized regions where technological progress stopped, or even reversed, but not worldwide, over a period of 50,000 years, during the era of modern humans. StuRat (talk) 20:43, 16 February 2013 (UTC)

Well, once again, there is no reliable source for the 50,000 year number--this could happen within the century--and global civilization could easily fall due to nuclear war or a plague, etc. The bottom line is, assuming there are people alive they will not go extinct because of an ice age itself. μηδείς (talk) 20:13, 17 February 2013 (UTC)

Unusually long interglacial, happens every 400,000 years I think. And also, due to anthropogenic greenhouse gasses, we are guaranteed at least 50,000 years of no glacial. Sagittarian Milky Way (talk) 21:12, 17 February 2013 (UTC)

There are several reliable sources positing that the present interglacial will last roughly 50,000 years based on climate modeling and drawing analogies with Marine Isotopic Stage 11, which was the last time an interglacial happened near a minimum in orbital eccentricity. See for example, Loutre and Berger, Climatic Change, 2000. There is far from a scientific consensus on how long the present interglacial will last (or would last without anthropogenic interference), but 50,000 years is a value that is commonly discussed. Saying that no such prediction exists is simply wrong. Secondly, all of the glacial transitions appear to have taken thousands of years to develop. Within the glaciations, there were abrupt regional changes, e.g. European climate swings occurring over a decade, but the global-scale changes took longer and were likely tied to the growth of ice sheets over thousands of years. A multi-kilometer ice sheet over northern North America simply can't appear overnight no matter what climate scenario one imagines. If an ice age starts to occur (which seems unlikely given the present tendency toward man-made global warming), then most of humanity will have generations to respond to it. As suggested though, tropical communities will see relatively little impact. During the last glacial, the tropics only cooled by about 1 C, while most of the cooling was at higher latitudes. Dragons flight (talk) 00:35, 19 February 2013 (UTC)

I remember a decade or so ago there was this speculation in Nature (I think) about how the Arctic Ocean thaws out entirely due to global warming, its upper layers become fresh water, plants flourish in it, sink to the bottom, consuming all the carbon dioxide and causing an Ice Age. Sounded kinda crazy to me at the time... what happened to the idea? Wnt (talk) 05:26, 20 February 2013 (UTC)

I've never heard that theory, and I agree it sounds rather crazy the way you describe. Perhaps you have some of the details wrong? Melting in Greenland can cause perturbations in the North Atlantic currents that lead to localized cooling (or less rapid warming) in Europe, but I'm not aware of any work discussing Arctic ocean plants sucking out all the carbon dioxide. Dragons flight (talk) 19:52, 20 February 2013 (UTC)

was robert boyle an idiot.? or only had a partial understanding of the world.

i would like to ask if robert boyls was an idiot - or he had only a partial understanding of the world.

because he 'invented' the perpetual-motion machine, the "self-flowing flask" (visible in his wikipedia page if you search for 'self-flowing flask'). In fact, if he had actually built it, he would have seen that it does not work.

so was he an idiot? today every school child knows "boyle's law." So, while he was naive and wrong, still, did he advanced the state of understanding in the world which shows he was not idiot?

similar with a perpetual-motion machine: especially when there is a readily available source of energy, such as a heat differential (at different water depths), a current moving against the bottom of a river, wind moving against a surface, large amounts of light that can be harnessed via the photovoltaic effect, natural motions of the earth or moon, negative acceleration that is already in use to bring vehicles to a stand-still in traffic, and so forth. All of these are an actual source of energy input - ulike boyle's contraption.

so, if he was not idiot surely same devices with actual source of energy input is not worthy of calling idiot? or should i abandon exploration of such systems? 86.101.32.82 (talk) 15:32, 16 February 2013 (UTC)

Boyle died in 1691. The law of conservation of energy (which essentially forbids perpetual motion machines) wasn't truly formulated and accepted until 140 years later. So it was far from obvious to Boyle that perpetual motion is impossible. Like many perpetual motion machine inventors - the problem that they state is always that some small optimisation in performance will make this theoretical machine work - even though their current practical implementation doesn't quite work. For a classic example of this kind of failed reasoning, check out the "SMOT" (Simple Magnetic Overunity Toy) - which was "invented" three hundred years after Boyle and doesn't work (of course)...despite endless numbers of faked videos on YouTube. The web is full of people who think they could make this perpetual motion machine work, if only they could just reduce the friction a tiny bit more - or get a tiny bit stronger magnet - or if they could just adjust that ramp to exactly the right shape. Those people are indeed idiots because there is rock-solid science that says that they are all wasting their time.

In the case of the self-filling flask, you can easily be lead to believe that it might work because surface tension will indeed make the height of the liquid in the thin tube be a little higher than in the main bowl of the goblet. Surface tension was not studied methodically until Benjamin Franklin in the 1740's, so Boyle had no science available to him to allow him to understand that effect. His reasoning behind the failure of the practical machine might have been that he imagined that the precise taper of the glass tube (required for this idea to work) might have been incorrect or that the material that it was made of caused a problem...something like that. The state of science in the 1680's (when several people reported this idea) was actually rather primitive. Alchemy was still widely practiced. Isaac Newton (who was definitely not an idiot!) was still practicing alchemy some 40 years after Boyle died. At the time Boyle was working, calculus had not been invented and even the concept of negative numbers had not yet entered European mathematics!

You, on the other hand, have the benefit of three hundred years of solid scientific experimentation and theory. "The Scientific Method" is well-established now. You have access to all of the great ideas of science at your literal fingertips here at Wikipedia and elsewhere. Mathematics has advanced beyond recognition and even children at the age of 8 years old understand the usefulness of negative numbers and teenagers are taught calculus. So, if still you think you have a perpetual motion machine, then you will most likely (and justifiably) be called "an idiot". But a machine that operates with a bonafide source of energy and which doesn't violate any of the laws of thermodynamics is perhaps not impossible.

SteveBaker (talk) 16:20, 16 February 2013 (UTC)

Justified? Hardly, and not by anyone who knows the difference between scientific knowledge and the scientific method. -Modocc (talk) 17:13, 16 February 2013 (UTC)

(ec) Robert Boyle was certainly smarter than your average guy (not an idiot) and he had a partial understanding of the world (who doesn't?). He understood energy, but not the current paradigm of thermodynamics, in which perpetual-motion machines of any kind are considered impossible, came later. In addition, our science is supposed to fit reality, thus its important to keep a critical eye on the models because sometimes theorists unintentionally build sandcastles and strawmen instead. In other words, their models do not entirely accord with reality and therefore get knocked down. As to what you should do, that is entirely your decision. -Modocc (talk) 16:48, 16 February 2013 (UTC)

These links are fascinating, thanks to everyone. It's amazing that these obviously impossible devices (due to thermodynamics, as there is no source external power) gets so many youtube view. Check this: http://www.youtube.com/watch?v=zz-Lupbn7mc 86.101.32.82 (talk) 20:04, 16 February 2013 (UTC)

Since paradigms have changed since Boyle's day and can change again, you may also be interested in the article on Paradigm shift. Modocc (talk) 21:43, 16 February 2013 (UTC)

And you might be interested in Maxwells demon to see that all the business abot perpetual motion machines is not at all obvious. Dmcq (talk) 01:12, 17 February 2013 (UTC)

Russian meteor

Meteor/asteroid coincidence

According to 2013_Russian_meteor_event#Coinciding_asteroid_approach, those two events happening 16 hours apart are just a coincidence. I'm not convinced:

1) What are the odds of such major events happening within 16 hours, if independent ? (Use whatever assumptions you like.) Here are my thoughts:

The meteor appears to be the biggest since the 1908 Tunguska event, so we could use 1/((2013-1908)*365) or 1/38325 chance of it happening on a given day. If we allow for the events to happen in either order, that's a 32 hour window, so let's multiply by 32/24 to get a 1/28744 chance of it happening within 16 hours of this particular asteroid. However, there must have been other asteroids as significant as this one. Here I'm less sure of the numbers.

2) Have scientists considered all ways in which the two events might be related ? For example, could a piece have broken off the asteroid on the last pass by the Earth, traveled roughly parallel to the main piece, but slowly diverged, then have gone around the far side of the Moon, quite close to it, and been wildly deflected this time ? StuRat (talk) 16:54, 16 February 2013 (UTC)

Well it isn't a coincidence. It is a secret, but as I know you can keep it, I will tell you. The Proxies, the space aliens from Proxima Centauri will not tolerate any space-faring races in their proximity, so they decided to eliminate our spaceports. 2012 DA14 was sent to destroy Cape Canaveral Air Force Station. Being the Proxies first try, they sent a heavy asteroid that would work disaster even when it didn't hit the target exactly. Lucky for us, it missed completely. With advances in their technology, they again sent now a cheaper, smaller, but faster and more well aimed object to destroy Baikonur. It was orchestrated as a double blow, so we wouldn't have the time to take defensive measures. As our radio transmissions need some time to reach them, they don't know of other launch sites yet.

The two orbits were not related. If something were broken off and then widely altered in orbit - it also wouldn't arrive at the same time . Rmhermen (talk) 19:29, 16 February 2013 (UTC)

Wouldn't they, under the scenario I gave ? They only diverge slightly until one goes behind the Moon, just hours before hitting/passing. StuRat (talk) 19:31, 16 February 2013 (UTC)

They came from opposite directions. If you look up any specific meteor shower you will see that all the meteors from one shower will move in the same direction from one origin in the sky, the constellation out of which they come giving the name of the shower; e.g., the Perseids. If these tow bodies had been associated they'd have come from the same area of the sky and been moving in the same direction. μηδείς (talk) 19:58, 16 February 2013 (UTC)

Not if one had gone around the far side of the Moon and had it's direction changed by 180°, as I suggested. Can someone tell me if the Moon was in the proper position for this ? StuRat (talk) 20:01, 16 February 2013 (UTC)

My first thought was that it could be some satellite orbiting 2012 DA14. As I am plain lazy, and besides, it would violate wikipedia rule WP:OR, I did not look at celestial mechanics to calculate the hypothetical orbit of the object that hit the earth around 2012 DA14 by myself. From imagination, it could well be some moonlet on its way back (back relative to the trajectory of the main object). 95.112.182.106 (talk) 20:30, 16 February 2013 (UTC)

Nope. This isn't biology, so some things really are impossible. :) And one of those things is a satellite orbiting a really, really weak gravity source, but doing so with such speed that when the primary nearly strikes the earth at that tremendous speed, the satellite strikes us at something near a right angle to it.

I'll go with the theory that friendly aliens moved the 150-foot meteoroid just enough so that it wouldn't hit us, but sent the other one at us to remind us that we ought to learn to do this for ourself. :) Wnt (talk) 21:16, 16 February 2013 (UTC)

Yes, the supposition is impossible. You are suggesting that two bodies travelling together with the same speed and trajectory and then closely passing by the moon (which was not predicted for DA14) were deflected so that one simply kept going (albeit much more slowly to explain the 16 hor time gap--although it arrived exactly when it had been predicted to do so for weeks), while the other one swang around the earth, but, instead of staying in orbit, then dropped down into the atmosphere from the entirely opposite direction. μηδείς (talk) 20:08, 17 February 2013 (UTC)

You don't seem to be understanding me at all. Here's a diagram:

          _                <-  . Little asteroid
         / \ Moon
         \_/  
               __
              /  \
             |    | Earth
              \__/
                                                                   <-  ∘ Big asteroid

      <-  .
         / \ Moon
         \_/  
               __
              /  \
             |    | Earth
              \__/
                                              <-  ∘

          _
        ./ \ Moon
         \_/  
               __
              /  \
             |    | Earth
              \__/
                                            <-  ∘

          _
         / \ Moon
        .\_/  
               __
              /  \
             |    | Earth
              \__/
                                           <-  ∘

          _
         / \ Moon
         \_/   
           .   __
              /  \
             |    | Earth
              \__/
                                          <-  ∘

          _
         / \ Moon
         \_/   __
            . /  \
             |    | Earth
              \__/
                                         <-  ∘

          _
         / \ Moon
         \_/   __
              /  \
              )   | Earth
              \__/
                                       <-  ∘

16 hours later:
          _
         / \ Moon
         \_/   __
              /  \
              )   | Earth
              \__/
        <-  ∘

You see, they already would have broken apart years before approaching Earth (this time), and would have separated in space and/or time since then. StuRat (talk) 00:02, 18 February 2013 (UTC)

Well, once again, impressive diagramming. But yes, I did actually expect that was what you meant. The problem is one of scale. The big and little asteroid were supposedly 50 and 150 ft across. At the sizes you show, the Moon and Earth would be much further apart, more like a ball bearing and a non-pareil at arms length from each other, with the nonpareil orbitting the bb once a month. The asteroids would be invisible dust grains on this scale. If they were associated, i.e., following the same path, each would then be affected by the moon's gravity if one was, but there was no such affect noted for the larger asteroid. Also, both dust grains would still have to travel the length of the arm in the same direction to get to the earth. The smaller asteroid would have to then do a very sharp half orbit around the earth (any less tight of a path and it would never strike the earth, just orbit or be deflected) but it was estimated to be travelling well over Earth's escape velocity when it hit, not under it, so some sort of "spiralling in" would have been quite impossible. μηδείς (talk) 01:18, 18 February 2013 (UTC)

They wouldn't be equally affected by the Moon, since one is extremely close to the Moon and the other is far away. I don't see why it would have to spiral into the Earth, if the deflection of the Moon shot it straight towards Earth. I do realize that the chances of such a deflection aiming it right at the Earth are low, but this relates to my first question. That is, are the odds of such a scenario lower or higher than this just being a random coincidence ? StuRat (talk) 03:30, 18 February 2013 (UTC)

No matter what you spot it and throw at it: 2 x 1km/s lunar orbit speed, the full Earth's escape velocity, whatever amount of the lunar escape velocity remains at 100 moon diameters, I'm not sure there's enough there. Sagittarian Milky Way (talk) 06:04, 18 February 2013 (UTC)

not to scale

StuRat, you are making ad hoc and contradictory assumptions which don't match the known facts. If the two rocks were associated, as is your primary assumption, they would be travelling in the same orbit around the sun in a "train" like the "string of pearls" fragments of Comet Shoemaker-Levy 9 which was disrupted by jupiter on its first pass and impacted jupiter on its second. If they were in the same orbit both rocks would have to pass by the moon relatively closely. But look at this diagram from our 2012 DA14 article. The sort of deflection you show would be impossible. A wide deflection would fling a rock off into space or put it in a wide orbit around the earth. A narrow deflection would leave the rock still coming from the same direction, which is not what happened. μηδείς (talk) 15:57, 18 February 2013 (UTC)

The Shoemaker-Levy 9 comet broke up just 2 years before it hit, versus many years, in my example. Over that time, the fragments would diverge far more. Looking at the "string of pearls" you can see that they're not all in a perfect line, even after only 2 years. Also, you talked about minor and major deflections, but how about moderate deflections ? StuRat (talk) 16:43, 18 February 2013 (UTC)

OK, now that you fixed the diagram, I think I finally see what you were saying. The Moon was not in the proper position, at the time. Of course, this would be over 16 hours earlier, so the Moon would have been in a slightly different position, but not on the other side of the Earth. StuRat (talk) 17:39, 18 February 2013 (UTC)

Comparison of the orbits of the Chelyabinsk meteor (larger elliptical blue orbit) and asteroid 2012 DA₁₄ (smaller circular blue orbit), showing they are completely dissimilar

I suggest you click on the image to the left and read its description at its file page (not the caption here) for a good brief explanation of why thyet are not considered related. μηδείς (talk) 17:45, 18 February 2013 (UTC)

Too bad they didn't put direction arrows on those two orbits or show them from the side view. If the two approached the Earth from the opposite sides, this might imply they were orbiting the Sun in opposite directions. If the orbits are both in the same plane, and going in the same direction, then they are somewhat similar, and having been deflected on a previous pass would still be possible. If they are headed in opposite directions, then probably not. Also note that we can only have a very approximate orbit for the meteor/comet which hit Russia, unless they've been able to find it in old photographs. StuRat (talk) 18:12, 18 February 2013 (UTC)

Yes, I had the same frustration. μηδείς (talk) 17:15, 19 February 2013 (UTC)

I see a new conspiration theory here. Honestly, wondering about coincidences after the facts is a waste of time at least. — Preceding unsigned comment added by 88.8.74.141 (talk) 20:29, 16 February 2013 (UTC)

A conspiracy requires conspirators. Or are you imagining a scenario where humans somehow caused this ? I believe looking at apparent coincidences after the fact has led to many scientific discoveries. StuRat (talk) 20:38, 16 February 2013 (UTC)

Well, moving a 10-ton rock is far from impossible, with even a small rocket. One might even explain the coincidence of dates as being because the nefarious party stupidly expected people to think it was a chunk of the famous meteor everyone was looking at. I imagine that the Russians will be looking over the wreckage of the meteor very carefully for signs of terrestrial rocket motors being attached, but then again ... a smart villain would have programmed his rocket to take off into space after it finished doing its job and long before impact. Wnt (talk) 22:18, 16 February 2013 (UTC)

To be clear the one that hit Earth was 10,000 tons, not 10 tons. Rmhermen (talk) 17:43, 17 February 2013 (UTC)

Ah; but how about the coincidence of the asteroid flyby, the meteorite strike, the pope retiring, lightning hitting the vatican, and North Korea testing a nuke? I tell you, something is definitely up. I'd advise checking out the CDC zombie apocalypse survival pages again. Gzuckier (talk) 07:54, 18 February 2013 (UTC)

Impact crater

Something else which confuses me is that the meteor appeared to be going through the atmosphere at a shallow angle, yet the impact crater in a frozen-over lake is circular, not elliptical, as I would have thought: 2013_Russian_meteor_event#Impact. Why is this ? StuRat (talk) 17:00, 16 February 2013 (UTC)

That's quite a common question and [3] hopefully will answer it for you. Dmcq (talk) 18:22, 16 February 2013 (UTC)

Thanks. StuRat (talk) 20:46, 16 February 2013 (UTC)

Window glass

Excuse me for hijacking the original questions. On some pictures it looks like the windows were "old fashioned" double glass windows, the kind easily broken by a mislead ball by some playing kids, not the kind of glass that is used nowadays with high thermal insulation and nearly indestructible even when deliberately using a hammer. So I wonder if the extent of destruction also has to do with cheap, or old, buildings.

I also wonder if buildings specially designed to withstand earthquakes, as Japan, would have had less damage or it protection against on does not give protection against the other.

95.112.182.106 (talk) 18:56, 16 February 2013 (UTC)

Much of the construction under communism was quite shoddy, yes. And, even since then, there are pockets of poverty where new construction, if any, is likely to be just as bad. StuRat (talk) 19:13, 16 February 2013 (UTC)

What this super glass you're referring to with for example 'high thermal insulation' which allegedly is used 'nowadays'? NZ is notorious for having poorly insulated homes with laws requiring decent insulation only very recent. Notably in many places window insulation is poor as double glazing is rare. The requirements for new homes since 2008 do make double glazing likely since it's difficult to achieve the requirements without it but obviously this is a very new requirement [4] [5]. Safety glass has been required since 1993 and is also required for replacements [6] but only where human impact is likely, in other words, not for many windows [7] [8] [9]. Nil Einne (talk) 02:48, 18 February 2013 (UTC)

If it really made that much of a difference, many homeowners who could afford it in NZ would do so to save their own money. Much of the population's winters are not quite as bad as most of the continental US I believe there might even be at least South Carolina-looking flowers in the equatorward of their two majorest cities (the one on the isthmus). Sagittarian Milky Way (talk) 03:03, 18 February 2013 (UTC)

Causes of raised pcp levels in the body

I would like to confirm what the causes for raised (Natural) PCP levels in the body are. I know that Pcp is a halucinogenic drug, I know there are natural levels of pcp in the body, I would like to identify what causes the natural levels to become elevated. & if Hyperthyroid could cause this. — Preceding unsigned comment added by 96.243.19.132 (talk) 17:41, 16 February 2013 (UTC)

Are you sure you mean PCP itself ? Piperidine is found in black pepper and also used in the production of PCP. StuRat (talk) 18:14, 16 February 2013 (UTC)

Did you confuse PCP with PTP (Protein tyrosine phosphatase)? PTPs are a class of hormones. I don't know what their connection to hyperthyroidism may be... --Jayron32 20:49, 16 February 2013 (UTC)

Hunting for endogenous phencyclidine I find a probably non-reliable source [10] which briefly describes a 1986 NIDA research monograph [11] (does anyone actually have access to these?) which postulated a PCP-like compound in schizophrenics. But so far as I know the mainstream thought runs toward PCP having a mix and match of effects on certain dopamine and glutamate receptors [12] which is dependent on the qualities of this exact chemical, which does not occur naturally in the body. As such, I would surmise that PCP-like states of mind might be assembled if these pathways are affected strangely enough in just the same proportion by natural or pathogenic physiological conditions, but there would be no particular mechanism to cause a mentally ill person to have that exact set of changes in these pathways as opposed to some other set that causes weird behavior but different weird behavior. But ... no promises that is true; this sort of biology is notorious for major do-overs. Wnt (talk) 21:12, 16 February 2013 (UTC)

It sounds like the OP has had a blood test and been told that they have elevated "PCP", which almost certainly won't be referring to phencyclidine (unless it was a drugs test). Maybe they misheard PCV. Either way, this is bordering on medical advice so until the OP asks a more specific question we can't answer it. Markr4 (talk) 13:33, 17 February 2013 (UTC)

Or maybe in this case, PCP actually stands for pentachlorophenol? 24.23.196.85 (talk) 07:28, 20 February 2013 (UTC)

what does it mean that relativity and qm are incompatible?

what does it mean that relativity and qm are incompatible? I've put this query into the google and read the first answer. it is from 2009 however and says : "Quantum Mechanics (QM) and relativity are both 100% accurate, so far as we have been able to measure (and our measurements are really, really good). The incompatibility shows up when both QM effects and relativistic effects are large enough to be detected and then disagree. This condition is strictly theoretical today, but in the next few years our observations of Sagittarius A*, and at CERN should bring the problems between QM and relativity into sharp focus."

since it is 2009 + 4 = 2013 can you elaborate thank you. 86.101.32.82 (talk) 22:07, 16 February 2013 (UTC)

General relativity is not incompatible with quantum mechanics, it is just that the theory is non-renormalizable, which means that the results of computations depend on exactly how you define the theory down to the smallest lengths scales. In case of renormalizable theories, what happens at some fixed lenght or energy scale in some experiment can be expressed in terms of a few other measuarable quantities to any accuracy that is desired. So, you can then eliminate the unknown physics at the very smallest length scales (or equivalently, the highest energy scales). Count Iblis (talk) 23:06, 16 February 2013 (UTC)

For the benefit of other readers, the answer you're talking about is here.

The extremely successful standard model of particle physics combines special relativity and quantum mechanics. Combining general relativity and quantum mechanics (into quantum gravity) has turned out to be amazingly difficult, but they are obviously not incompatible since they coexist in the real world.

There is a philosophical/foundational problem with combining even special relativity with quantum mechanics, which is that both special and general relativity treat time and space in essentially the same way, while in quantum mechanics they are totally different: This is called the problem of time, and Wikipedia should have an article on it but currently doesn't. It probably has something to do with the difficulty of making quantum gravity work, and it's surprising (to me, anyway) that it doesn't cause more trouble in the Standard Model as well.

I don't know why "The Physicist" thought that observations of Sagittarius A* (a black hole) or experiments at CERN (presumably meaning the LHC) would cast any light on quantum gravity. Sagittarius A* is very far away and we can only vaguely measure its properties. The LHC has a maximum design collision energy of 14 TeV, while quantum gravitational effects are expected to become significant at around 10,000,000,000,000,000 TeV (the Planck energy). Many particle physicists did hope that the LHC would find something new that would tell us something about quantum gravity, but it hasn't happened yet. -- BenRG (talk) 19:14, 17 February 2013 (UTC)