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June 17

Average weight for Americans and Europeans

Where can I find the average weight for (adult) American men & women and European men & women? --CGPGrey (talk) 12:28, 17 June 2011 (UTC)

A search for 'average weight american' easily finds [1]. My guess even before searching is trying to find an average weight for Europeans is unlikely to be easy and a search for 'average weight European'. I would suggest you compare different European countries. If you really want an average for 'European' you should at least definite the term. Do you mean all EU countries only? Nil Einne (talk) 12:43, 17 June 2011 (UTC)

The WHO keeps a lot of health facts for countries throughout the world here. For weight, I believe they only report the percent that are obese instead of actual weight. You can go into the data repository to get actual weight values. The result will be a bit useless. For example, I only have around 2 million patients in the data set I'm using right now and the average weight is 84+-27kg. That is a HUGE variance and it give no information about the distribution. -- kainaw™ 12:49, 17 June 2011 (UTC)

Obesity is usually determined by body mass index which has numerous criticisms (see the article) but is far better then weight alone. You can find average BMIs for various European countries fairly easily. E.g. [2]. However the OP is apparently interested in weight Nil Einne (talk) 13:41, 17 June 2011 (UTC)

This BBC article has figures for America and Britain (wouldn't be such a bad call for Europe, depends how far east you include) that they believe are comparable. Grandiose (me, talk, contribs) 13:15, 17 June 2011 (UTC)

I'm not convinced the UK is a good choice to represent Europe since various sources say the UK is one of the highest in Europe [3] [4] for females. Notably France is on the lower end of the scale (not sure about Germany, I guess it's in the middle since usually not mentioned.) That's for BMI not weight but still seems a bad choice if you want an average European figure. Nil Einne (talk) 13:41, 17 June 2011 (UTC) Edit: [5] is the study mentioned in the Daily Mail article. It has a lot of data on the BMI of different countries including for Western Europe (as they define it) although is primarily analysing the change rather then just the current figures. 14:05, 17 June 2011 (UTC)

(e/c, not significantly.) Well, another article suggested French women - the thinnest - were about 9st11. The BBC article says British 10st3-and-a-half. So perhaps we can refine the average figure to only a little under the British one, perhaps 10st. Depends how accurate the OP needs. That would be around 1st lighter than America (this article actually gives a somewhat higher figure than 11st, 11st10lbs. Grandiose (me, talk, contribs) 14:09, 17 June 2011 (UTC)

Well the Telegraph article gives 70.6kg UK women for 2008 (well the Lancet figures seem to be from then). Having said that is also gives 63.5kg for 1980 and I doubt it went from 63.5 to 65 kg in 2001/2002 (BBC article is 2004 but [6] suggests the data is from then) then to 70.6 kg in 2008 suggesting these figures aren't from really comparable.

The difference in BMI from the Lancet article (in 2008 26.9 for the UK, 24.8 for France) definitely suggests a bigger difference although we don't know if the average height is the same (but the average height in the Telegraph article and the article on French women's weight is the same, although that article is from 2006). This meanwhile gives 66.7kg for UK women [7] in 2006. I notice some sources are using a BMI of 26.2 for UK women but the Lancet gives this as the 2000 figure (for comparison the French were 24.7 in 2000).

BTW if the OP does want to use BMIs, the 2000 figure for US men is 27.7, 2008 is 28.5; 2000 US women is 27.5, 2008 28.3. For UK men 2000 is 26.6, 2008 is 27.4. For French men 2000 is 25.4, 2008 is 25.9. These figures are all taken from the Lancet megareview so are intended to be comparable.

P.S. The average weight for US is 71 kg in the BBC article (the time frame is unclear [8] but let's take it as 2001/2002) vs 74.7 kg by the CDC (which appears to be using 2006 figures). In other words, it may be fair to compare the Size figures since they come from a comparable data source but comparing those to other figures is probably not a good idea. In terms of the UK average as a European average, since the data is fairly old it's not quite as bad (since UK women seem to be increasing faster then the French at least) although it's possible/likely? the average weight for French women would be lower then the figures from the above article if comparable SizeFrance figures were used.

Nil Einne (talk) 22:30, 17 June 2011 (UTC)

I believe this is from the same Lancet survey and fun to look at.[9] --JGGardiner (talk) 06:11, 18 June 2011 (UTC)

Figures for the US from old data must be corrected for inflation:

Americans are not just getting fatter, they are ballooning to extremely obese proportions at an alarming rate.

Count Iblis (talk) 15:00, 17 June 2011 (UTC)

• BMI at least factors in height. It would be silly to compare the weight of tall and short people without factoring in height, and conclude a taller population was fatter just because they weighed more. Americans seem to be bimodal. I see some children and young adults who sit and eat and plump up. If their Mom tells them to "Go play," they sit in front of a video game with a supply of snacks. Others run all the time, go to health clubs, ride bicycles, participate in competitive sports like soccer or swimming, and stay quite thin and well muscled. I suppose if there were a major conventional war, the lard-butts could be drafted to remotely fly combat drones using their well-honed joystick skills. Edison (talk) 15:19, 17 June 2011 (UTC)

• ...and the healthy ones would be drafted and sent to front line infantry positions. Hmmm, pass the Cheesy Poofs please. StuRat (talk) 18:05, 17 June 2011 (UTC)

You might be interested in Drop Bears.5BYv8cUJ (talk) 11:01, 18 June 2011 (UTC)

• That's supposedly what happened to the French. I used to hear that the Napoleonic Wars shortened the height of the average Frenchman by several inches. (I guess DeGaulle's ancestors were 4-Fs). ←Baseball Bugs ^{What's up, Doc?} carrots→ 19:33, 17 June 2011 (UTC)

I don't think we should make any assumptions here. There is convincing evidence that adenoviruses are involved - for all we know, obesity is the outcome of some kind of Cold War battle. There's also epigenetics to consider, which involves some truly fearsome risks that people really haven't considered at all. If the effects of the easy life are passed on from parent to child, accumulating as methylations or chromatin changes, there's truly a chance that we get to a point in a few generations where children are metabolically prone to unlimited weight gain. Likewise, we might find over the course of a few decades that some unknown factor added to our environment has led 90% of newborns to be autistic. Stuff like this could happen, and if it does is almost impossible to predict it, figure out why, or stop it. Wnt (talk) 23:32, 17 June 2011 (UTC)

So the Soviet Union won after all? Nil Einne (talk) 01:07, 18 June 2011 (UTC)

I don't think that the common cold is usable as a bio-weapon -- it's just not lethal enough. 67.169.177.176 (talk) 04:07, 20 June 2011 (UTC)

You must be right, the USSR has made everyone lazy and sit in front of a TV or a computer all day instead of going outside for some physical activity. Or maybe it has more to do with the fact that the TV now has 500 channels instead of 5 and the computer can do more then play pong. Googlemeister (talk) 15:18, 20 June 2011 (UTC)

Bawris

What are Bawris?Why are these being recieved due to peoples participation? — Preceding unsigned comment added by Rudraksh Parey (talk • contribs) 14:21, 17 June 2011 (UTC)

I take it you're not referring to Stepwell? Nil Einne (talk) 14:31, 17 June 2011 (UTC)

Seriously, I searched really hard, but I have no idea what you are asking, Rudraksh. Can you attempt to re-phrase your question?-RunningOnBrains^(talk) 18:27, 18 June 2011 (UTC)

Small photography

I am interested in taking photographs of relatively small things. Not electron microscope stuff, but I would love to be able to, for example, take a clear photograph of a single poppy seed at the level so that it took up most of the frame. Can anyone give me a short explanation of the equipment I would need? and any tips? I know this is not very properly a science question, though it is somewhat in the bailiwick, and the miscellaneous desk is in read-only mode (there's a note to that effect when you try to post there). Thanks.--108.14.194.26 (talk) 15:26, 17 June 2011 (UTC)

The article on Macro photography might provide some guidance, but you would need a powerful lens to photograph a single poppy seed full-frame. I haven't tried this level of magnification, so await some experts to give tips. Dbfirs 15:38, 17 June 2011 (UTC)

The most critical piece of equipment for macro photography is a macro lens. This is a lens with a short minimum focusing distance; it usually also has a large aperture and short focal length. Most macro photography guides and tutorials also recommend a very large lens aperture so that you can collect a large amount of light in a short time and control your depth of field. Many macro lenses also have a short focal length (because this helps frame close subjects and makes it easier to design a short minimum-focus-distance. On top of this, you may want some "whisker" flash equipment for off-center illumination. Here's an example of a full kit, the Nikon SB-R1 "Close-Up Flash" system. If you have a large budget, a full-frame sensor can make a big difference; the optics are much more expensive, but this allows the optics to resolve a more sharp image, which makes a big difference when you are shooting a very close-up object.

You don't require any of this for macro-photography; in fact, modern mobile-phone cameras and point-and-shoot cameras usually have wide-angle lenses with ridiculously short close focal distances. (This is an "added bonus" due to their compact size). But, you can control image quality, lighting, noise, and other photographic and optical parameters much more closely when you switch to a DSLR camera.

Personally, I do not shoot much macro-photography, but when I do, I use the (very unconventional) 70-300mm lens on my Nikon D90. My close focal point is about 2 meters away, so it does not appear to be macro-photography; but with the DX crop-factor and 300mm focal length, I actually produce a larger "magnification" (pixels per mm of subject, or "reproduction ratio") than most of the macro-lenses I have compared. I should also say, the Nikon 60mm "Micro" produces incredibly sharp pictures at close focus; but I don't want to spend 600 dollars on what I consider a "single-purpose" piece of equipment.

Here's a great tutorial on macro photography equipment and technique from Ken Rockwell. And, here's an official tutorial from Nikon, Minimum focus distance. Nimur (talk) 16:25, 17 June 2011 (UTC)

"Single poppy seed full frame" is somewhat out of the range of macro photography, and more in the range of microscope photography. While typical micrographs are usually thought of at the 400x/single-cell level, you can also do ~10-40x photography, e.g. with a dissecting microscope. I haven't done any photography with them, but I have used dissecting scopes to examine small object, and you can get good detail without having to do any special preparation. A decent dissecting scope with a camera mount shouldn't be all that more expensive than a decent DSLR macro lens. (P.S. The Refdesk randomly being read-only for IP users is a known issue - usually it can be resolved simply by refreshing the page in your browser.) -- 140.142.20.229 (talk) 16:50, 17 June 2011 (UTC)

There's a difference between "full-frame" and "full-frame." In common parlance, full frame means "takes up the entire area of the picture," which is a very useless term - because you can crop any photo so that the subject fully fills the entire crop area. "Full frame" in photographic jargon means "projects an optical image whose size is equivalent to that projected onto 35-mm film." This is a much more specific description - it tells you how much optical zoom you have provided; if a poppy-seed fills a full-frame camera, you can calculate the magnification ratio at any given subject distance, and therefore pick the lens focal length you need to do it. (For example, here's a free online calculator). And, as seen here, a poppy seed shot through a 50mm macro lense will nearly fill APS-C - no microscope required! A longer focal length lens will fill full-frame, but you'll have to use every trick in the book to focus (and brightly illuminate) the poppy seed. Nimur (talk) 17:51, 17 June 2011 (UTC)

I second the suggestion for using a microscope with a camera. One potential problem is the vibration created by hitting the shutter button, which can ruin the photo. This could be handled with a timer that allows time enough for the vibration to settle, or with a remote trigger (wired or wireless). StuRat (talk) 17:59, 17 June 2011 (UTC)

Thanks for all the information, everyone. I have printed this out and will check out the external sources and links at my leisure!--108.14.194.26 (talk) 21:49, 17 June 2011 (UTC)

As for getting really close, as you said, there are a couple of options. This lens can shoot extremely close (but comes only for Canon mounts). You can also try a macro lens that has a relatively long focal length, such as this or this, and then using close-up filters and tele-extenders to get even closer. And then you can try to make a beast like this or this, with a reverse lens attached to a macro lens. And you can always attach a camera to microscope too. --T H F S W (T · C · E) 05:08, 18 June 2011 (UTC)

Vibration shouldn't be a big deal for objects on this scale, as long as the microscope mount is pretty stable. I take photos of objects this size all the time, using a good quality microscope at low magnification, and a camera pressed up against the microscope's eyepiece (a cheap clear filter attached to the front prevents damage to the lens). For good pictures, focus the microscope by looking through the eyepiece and keeping your eyes relaxed. Then manually focus the camera at infinity. Disable the flash, of course. Depending on the camera, you may also need to set the exposure manually. You will need a bright light source to illuminate your sample. I use a ring light designed to attach to a microscope.--Srleffler (talk) 16:59, 20 June 2011 (UTC)

A good photo of sesame and poppy seeds. See the article Poppy seed. Cuddlyable3 (talk) 14:25, 18 June 2011 (UTC)

Does a Encyclopedia Naziana exist?

Does a Encyclopedia Naziana exist?Smallman12q (talk) 16:02, 17 June 2011 (UTC)

Not according to Google. Red Act (talk) 16:36, 17 June 2011 (UTC)

Yes and we can be sure that there exists one where Smallman12q is editing :) Count Iblis (talk) 18:29, 17 June 2011 (UTC)

To provide a serious answer (as others might be reading this, you know), a four-volume condensed edition of Brockhaus, which contained a considerable amount of information on contemporary German life, was published in 1938 - see [10]. It only merits a passing mention in our article on the encyclopaedia - why, I won't speculate. Tevildo (talk) 19:05, 17 June 2011 (UTC)

Big bang?

Is an expansion of the Universe starting from a point in the "Big Bang" the only explanation of the red shift observed by astronomers? — Preceding unsigned comment added by 84.209.86.125 (talk) 19:19, 17 June 2011 (UTC)

No. In particular Hoyle's Steady State theory was proposed to explain the observed red shift. But other evidence rejects the SST, in particular the cosmic microwave background radiation. BBT (or really the set of very similar "universe was once exceedingly small" theories we might collectively call the BBT) also explains the relative preponderance of elements very nicely. -- Finlay McWalter ☻ Talk 19:29, 17 June 2011 (UTC)

There is also the tired light theory which has also pretty much been ruled out. Dauto (talk) 20:02, 17 June 2011 (UTC)

Incidentally, if you're interested in this kind of thing, I can recommend Simon Singh's book Big Bang: The most important scientific discovery of all time and why you need to know about it. Despite its title, the book is mostly about the evolution of cosmological ideas and the weighing up of evidence that forced paradigm shifts (gosh that sounds boring); it's about why smart people believed wrong things and how new evidence made for better knowing (that sounds better). -- Finlay McWalter ☻ Talk 20:12, 17 June 2011 (UTC)

You could come up with alternate explanations, but Occum's Razor comes into play, and thus the simplest theory to explain why everything seems to be moving away from a single point is that it is. StuRat (talk) 23:13, 17 June 2011 (UTC)

But any theory is simpler than decompression with a bang of everything from a mathematically singular, physically impossible, MAGICAL MYSTICAL point. Some have thought that dubbing the theory after it was hypothesized "Big Bang" was meant to ridicule its unlikeliness. It is also unfalsifiable. Cuddlyable3 (talk) 12:38, 18 June 2011 (UTC)

It's not unfalsifiable; there are many predictions based on the Big Bang theory which can be proven true or false. The reason the theory became so prominent is due to one of these predictions: the Cosmic background radiation. Physicists predicted it should exist, and two radio technicians who didn't even know about this prediction found it. I'd say that's almost the opposite of unfalsifiable.-RunningOnBrains^(talk) 18:31, 18 June 2011 (UTC)

Of course, there are many hypotheses on what started the big bang: brane theory, the big crunch of another universe or a scientific experiment by higher-dimensional beings, for example. See also non-standard cosmology. ~AH1 ^(discuss!) 15:19, 18 June 2011 (UTC)

Big bang cosmology is about the evolution of the universe from an early hot, dense, uniform state of (as yet) unknown origin. It is not about a bang, or a singular point. -- BenRG (talk) 21:31, 18 June 2011 (UTC)

Fixing nesting box on to tree trunk

I've got a wooden nesting box, without any bracket or screw holes. What is the best way to fix it to a tree trunk of about one foot or so diameter? 92.24.136.31 (talk) 21:14, 17 June 2011 (UTC)

The RSPB has a page of info about nest boxes here, which says "Fixing your nestbox with nails may damage the tree. It is better to attach it either with a nylon bolt or with wire around the trunk or branch. Use a piece of hose or section of car tyre around the wire to prevent damage to the tree." It also has advice about locations for the box, which varies depending on the species of bird you're accommodating. -- Finlay McWalter ☻ Talk 21:30, 17 June 2011 (UTC)

Perhaps bungee cords would work, provided you can find a place to attach the hooks to the box (you may need to drill holes). The flexibility they provide would allow for tree growth. You'd also want to put the box above where a branch leaves the trunk, so the weight of the box is supported by the branch. StuRat (talk) 23:03, 17 June 2011 (UTC)

And please make sure it is in shade or faces north, otherwise the chicks can roast to death on a sunny day. If you live in the northern hemisphere there is not much point in putting it up before next year.--Shantavira|^{feed me} 10:41, 18 June 2011 (UTC)

We hung them in scouts using hanger wire and did it in the fall. I am sure the birdds will not mind when the boxes are hung so long as they are hung before they nest. Bungee cord is ugly and expensive. μηδείς (talk) 02:11, 20 June 2011 (UTC)

How should I attach the wire to the boxes themselves? 92.28.240.2 (talk) 09:27, 20 June 2011 (UTC)

Detection of light at great distance

Hi. Suppose I have an automatic gun on a rotating turntable, firing ten rounds a second or something. If I stand some distance away, then (ignoring all "indirect" evidence like sound and sight) I can only detect that the gun is firing if I happen to be standing in the right place so that a bullet actually hits me. On the other hand, if someone drops a rock into the middle of a pond then I can, in principle, detect the ripples anywhere on the perimeter of the pond at any distance.

OK, so now suppose I sweep a torch across the heavens. Would anyone along that path, say in a distant galaxy, be able in principle to detect the torch, like the waves in the pond? Or would only those lucky people hit by a photon be able to detect it, like the turntable gun? If the latter, then "what happened to the light waves in the gaps"? 86.160.209.60 (talk) 22:00, 17 June 2011 (UTC)

I believe light behaves like a particle in this instance. That is, the distant planet would have to be lucky for one of the photons from your flashlight to reach it. We have dim objects in space that our best telescopes can only detect as an occasional photon, but a computer (or previously long exposure film) can eventually form an image out of those individual photons. As for why light is sometimes a particle and sometimes a wave, or how you can predict which it will be at an given moment, I'm clueless there, and I don't think I'm the only one. StuRat (talk) 22:55, 17 June 2011 (UTC)

It is not uncommon for a single photon to act like a circular wave, yet be detectable in only one place. See the classic double-slit experiment. One single photon, emitted from a source, moves through two slits, interfering with itself like a wave, as evidenced by the probability of detecting it varying according to wave interference. Yet it's just one single photon that lands in one single spot. Wnt (talk) 23:26, 17 June 2011 (UTC)

Can a single photon interfere with itself? I thought the interference only built up with many photons. [ignore that; I didn't properly take on board your "as evidenced by..."] But carrying on from what you say, does that mean that anywhere along the torch's sweep you have some probability of detecting a photon -- but whether you will or not at any given place can be determined only by trying to detect one, rather than it being (in principle) pre-determined from the moment the light left the torch (as is the case in the bullet analogy)? Does that question make sense? 86.160.209.60 (talk) 00:32, 18 June 2011 (UTC)

Well, that's where thing gets weird. On countless planets across the universe, people look up, waiting for that first photon your torch emitted. But only one shall find it. The photon has not decided, before it has been seen, where in the cosmos it might be. And yet once it decides on the world of its choice, all those countless others will look up in vain. One way to put it is that the state vector "collapses"; the detection removes the chance of it being detected anywhere else by a "spooky action at a distance". It is faster than light transmission of information, in a sense - the catch being, no one can say in advance where it will be found, so there is no predicting the information to be transmitted - just like with entangled particles. I am more fond of the transactional interpretation in which the detection sends a wave backward in time to match the first. Wnt (talk) 06:47, 18 June 2011 (UTC)

Thanks Wnt, your answers have been very ... ahem ... illuminating. 86.160.222.31 (talk) 11:19, 18 June 2011 (UTC)

The only reason you can detect the ripples on a pond is due to what you call "indirect evidence" (in this case, light reflecting from the ripples and reaching your eyes). Take this away (say, drop the rock into the water on a really dark night, or when blindfolded) and you'll only be able to detect them by actually dipping some part of your body into the water and feeling the ripples on your skin. Same thing with your flashlight -- the only way anyone can detect it is either if they're in the path of the beam, or by seeing light that has been scattered by the atmosphere. Also keep in mind that even in the absence of any scattering or absorption, the light will spread out and therefore decrease in intensity as the inverse-square function of the distance, so that even by the time it reaches the Moon, it will be so dim as to require advanced sensors for detection. -- An American ultranationalist 67.169.177.176 (talk) 23:30, 17 June 2011 (UTC)

NOTICE to whomever it may concern. It has come to my attention that your intra- and intergalactic electromagnetic intercourse may be impinged by radiations emanating from this planet on which I have assert right of occupancy as a partial spherical-polyhedral wedgeholder. I wish to assure you that no such radiation, coherent nor pulsed, is authorized as a communication by me nor is it emitted on my behalf. As a representative of decent humans I beg to offer apology for any inconvenience, and trust that no unpleasant misunderstanding will marr the mutual cordiality of our relations as neighbours. Klaatu barada nikto. Cuddlyable3 (talk) 14:12, 18 June 2011 (UTC)

June 18

Text readable only at low zoom

You probably know who this was. I am neither Leon Harmon nor Bela Julesz. I made this image using their idea. Cuddlyable3 (talk) 13:09, 18 June 2011 (UTC)

How do you explain something like this? The text seems almost completely unreadable at high zoom - yet in the fine print, which seems clearly legible to me, the exact same picture is present (use the Zoom on your browser if you don't believe me). Is there a scientific description of this phenomenon? Wnt (talk) 23:17, 17 June 2011 (UTC)

Seems to me like pixelation effects of a low-resolution text image. In other words, the letters are made of tiny pixels, which get magnified along with the image at higher zoom levels and act like a sort of pattern-disruptive camouflage for the letters. I know this from personal experience -- I've had much the same problem with the cover I created for my book, which had to be completely reworked as a result. 67.169.177.176 (talk) 23:40, 17 June 2011 (UTC)

(edit conflict) The rendering in squares of homogenous hues is dependent for clarity on failing visual resolution which occurs more at the smaller scale than at the larger scale. Bus stop (talk) 23:44, 17 June 2011 (UTC)

It's a "can't see the forest for the trees" issue. If you can make out individual pixels, your brain focuses on those, not the overall image. This is why zooming in on something only helps you make out detail to a point, then things start to get worse. StuRat (talk) 23:54, 17 June 2011 (UTC)

This is the phenomenon that Leon Harmon and Bela Julesz described in their 1973 Science paper, Masking in Visual Recognition: Effects of Two-Dimensional Filtered Noise -- exemplified by their famous pixelized image of Abraham Lincoln. Looie496 (talk) 00:10, 18 June 2011 (UTC)

Thank you for that link, Looie496. This paper is amazing. Nimur (talk) 00:53, 18 June 2011 (UTC)

The Abraham Lincoln picture is really cool. I just printed it A4 size, and when you hold it close in your hand it looks totally meaningless. If you then prop it up and walk away from it across the room, it gradually becomes clearer and clearer what it portrays. 86.160.209.60 (talk) 03:03, 18 June 2011 (UTC)

• Just curious, the OP says that the small text "seems clearly legible". For me, it is far from being "clearly legible" (though I am probably about 80% sure I can guess what it says). Is it "clearly legible" to everyone else? Btw, I can read the large version better if I almost close my eyes so that everything is very blurry and I can no longer see the sharp pixel outlines. 86.160.209.60 (talk) 00:37, 18 June 2011 (UTC)

• It depends on the resolution, display clarity/sharpness and viewing distance. It's illegible (can't even guess what it says) on my CRT at my default zoom. It's fairly legible on my LCD at default zoom. It's legible on my CRT at greater zoom although still not as clear IMHO. At in between zooms it becomes somewhat legible like for you. (Although I saw it on my LCD before this.) Past that it starts to become illegible again. If you want to do more experiments I suggest an image viewer with high quality zooming interpolation but fine zooming control. Nil Einne (talk) 00:57, 18 June 2011 (UTC)

Oh yes, of course. When I zoom to 200% it is easy to read. 86.160.209.60 (talk) 01:05, 18 June 2011 (UTC)

Note that the rendered text uses subpixel rendering, which makes an assumption about the layout of pixels in your monitor. Many modern monitors do not use the conventional "RGB" side-by-side rectilinear pixel. For example, an iPad display looks like this under a microscope. If text is rendered for sub-pixel antialiasing, assuming an RGB-horizontal array pixel geometry, it will look very different on an unconventional display. Nimur (talk) 01:14, 18 June 2011 (UTC)

Really? That blue text over there? Are you sure? It doesn't have the rainbow artifacts on the edges that I would normally associate with sub-pixel rendering. APL (talk) 02:11, 18 June 2011 (UTC)

I think it says "PREZOOM", whatever that means. Plasmic Physics (talk) 05:27, 18 June 2011 (UTC)

It does? I thought it said "FREEDOM". --Jayron32 05:30, 18 June 2011 (UTC)

Yes, it says "freedom". It's amazing that such a heavily pixilated image still contains enough information for our eyes to decode it. Dauto (talk) 07:49, 18 June 2011 (UTC)

If you think about it a bit, it's actually not particularly amazing. (Sorry to be a wet blanket.) The regular English alphabet contains 26 letters, represented by 52 symbols (upper and lower case). That's a bit less than 2⁶ unique symbols. In the image shown, there's an array of something like sixteen pixels for each letter. If we limit ourselves to turning each of those pixels (bits) on or off, we have 2¹⁶ possible unique 'characters'; roughly speaking, that's space for a thousand different alphabets. In practice, of course, it doesn't work quite like that. On the up side, we actually are allowed several different values possible values for each pixel—if we conservatively estimate each pixel might have one of four readily-distinguishable colors then there's room for a billion unique characters.

On the side of reality (the 'down side') human alphabets are generally not designed for efficient use of low-resolution pixels—though when we put our minds to it, we can certainly design such representations; consider Braille. Written characters are generally composed of strokes rather than arrays of stippled dots; this means that lines of adjacent pixels in their graphical representation will all have the same value, and will tend to be surrounded by buffers of wasted white space. As well, some characters have shapes that are similar to one another: o, c, e, for instance. Even then, though, we're partially rescued from ambiguity by our human pattern-matching abilities. If I see a the partially obscured W_k_p_d_a or __kipedia or Wikipe___, I've got a pretty good shot at correctly assigning the missing letters. TenOfAllTrades(talk) 13:36, 18 June 2011 (UTC)

Sorry but that's nonsense. Dauto (talk) 19:45, 18 June 2011 (UTC)

Sorry, I may have been too concise, or slipped in some oversimplifications in places. Which part did you not understand? TenOfAllTrades(talk) 21:01, 18 June 2011 (UTC)

Your demonstration is incomplete. Most of the pixel combinations do not represent anything. You have not assessed what fraction of these combinations can be used to represent letters. More to the point, the pixilated picture contains the same amount of info when you zoom in but becomes illegible. That means that some heavy information processing is being performed by the eyes and that's what makes it amazing. Dauto (talk) 03:03, 19 June 2011 (UTC)

Actually, it doesn't say anything - it's just a pattern of pixels that resembles what we think it ought to. It is simply a mind trick played by our brain, as it tries to make sense of the visual world. Plasmic Physics (talk) 08:44, 18 June 2011 (UTC)

Sorry but that is also nonsense. Dauto (talk) 19:45, 18 June 2011 (UTC)

-RunningOnBrains^(talk) 04:26, 19 June 2011 (UTC)

See CAPTCHA. Cuddlyable3 (talk) 13:19, 18 June 2011 (UTC)

Appealing to Plato's cave rarely contributes anything to a discussion. APL (talk) 20:40, 18 June 2011 (UTC)

What is Plato's cave? 67.169.177.176 (talk) 21:53, 18 June 2011 (UTC)

See Plato's Cave. Tevildo (talk) 22:02, 18 June 2011 (UTC)

Now why is that article not in the category Pseudoscience? 67.169.177.176 (talk) 00:20, 20 June 2011 (UTC)

I was not refering to Plato's cave, I highlighted the fact that the letters you supposedly see doesn't actually exist. This is proven by the enlarged image. Plasmic Physics (talk) 08:03, 19 June 2011 (UTC)

Does Abraham Lincoln with hat actually exist? Cuddlyable3 (talk) 15:45, 19 June 2011 (UTC)

I would say that the letters we actually see do indeed exist. This is proven by the smaller image. Dauto (talk) 16:09, 19 June 2011 (UTC)

Cuddlyable3: yes he does exist, but that is not an image of him; yes, the letters do exist, but that is not an image of them.

Dauto: the enlarged image is carries the same amount of information as the smaller image, ergo the enlarged image clearly does not contain letters. And circular reasoning does not work. Plasmic Physics (talk) 07:07, 20 June 2011 (UTC)

This is kind of silly reasoning. It invites the question, "at what level of information do they cease to exist?" which I think points out how silly it is. The question is not whether they exist in an ontological sense. The question is about human perception and pattern matching, which is what everyone else has been gesturing towards. --Mr.98 (talk) 14:15, 20 June 2011 (UTC)

The letters clearly exist. At larger sizes we're distracted by the more obvious pattern of the pixels. Like the Lincoln image. For some reason we're only capable of seeing one of the patterns at a time.

The secondary pattern doesn't have to be pixels. That's just a side-effect of the technology used. Hybrid Images can be made with all sorts of images. The most famous is a picture that contains both Marilyn Monroe and Einstein[11], super imposed in such a way that the Einstein image is obvious from up close, but the Monroe image is obvious from far away.

Lots of other optical illusions exploit tricks where our brain latches onto one or the other interpretation of an image but not both simultaneously. (The dancer can't twirl both ways at the same time, the rabbit and the duck can't coexist, etc.)

In short, yes, both images contain the same data, but we can't see the text in the larger image because of a limitation in the way our visual cortex functions. APL (talk) 22:59, 20 June 2011 (UTC)

The method of presentation requires the use of squares of varying hues, although the hues within each square are required to be the same throughout. We only see the letter as a result of our failure to visually resolve the image at a certain scale of presentation. Bus stop (talk) 14:31, 20 June 2011 (UTC)

Does the smallest image contain information indicating it represents a word? Plasmic Physics (talk) 08:21, 21 June 2011 (UTC)

Not in any way that I know to decode it.

What does that prove?

That it's possible to reduce an image of letters to the point where the original letters can no longer be decoded? No one is arguing that.

The point is that when it is possible to decode the pixels into letters it's because the information is still there, even if the information isn't obvious to humans in every possible way you want to look at it.

Many people have trouble reading things that are upside-down, but surely you wouldn't argue that the meaning of a sign is lost if it's hung upside down? It simply means that our brains are not perfect computers and sometimes how data is presented makes a big difference as to whether or not we can decode it. APL (talk) 20:51, 21 June 2011 (UTC)

My point is that the amount of information contained in small script like this, is exajurated in an illusional construct of our brain, see apophenia. Plasmic Physics (talk) 06:32, 22 June 2011 (UTC)

Spotting Jupiter with the naked eye during daytime

This article mentions successful observations close to Sunset. But Jupiter now rises before the Sun does, and then you get a better opportunity to try to spot it when the Sun is in the sky, you just follow it starting at dawn for as long as possible.

I was wondering if people have done this and what the record (in terms of how high the Sun is in the sky when jupiter can no longer be seen) is. Count Iblis (talk) 03:26, 18 June 2011 (UTC)

It probably depends a lot on where you are, and what the atmospheric conditions are like when you are looking. Even if it is a nominally "clear" day with no clouds, there are a lot of factors which can affect if stars and planets are visible during the day. I have personally seen both Venus and Sirius during the day time, and the article on Sirius notes that it has a lower apparent magnitude than Jupiter, meaning that under ideal conditions, Jupiter should be visible when the sun is out. --Jayron32 06:06, 18 June 2011 (UTC)

There is a risk in doing this with a telescope, however: leaving the telescope statically pointed at any planet visible before sunrise means that the Sun could eventually enter the field of view–exploding the telescope. ~AH1 ^(discuss!) 15:12, 18 June 2011 (UTC)

Or permanently blinding you if you happen to be looking through it at the moment. 67.169.177.176 (talk) 20:25, 18 June 2011 (UTC)

If we(humankind) build 1 000 000 000 starships, Project Daedalus mass, that is around 50 000 tons each

If we(humankind) build 1 000 000 000 starships, around Project Daedalus mass, that is around 50 000 tons each.

We would use only resources found and mined on Moon. How big percent of Moon mass such advancement consume? Will humans who would still live on Earth notice any change to the ocean tides, how Moon shrink in size at nighttime?

Most of that 50 000 tons of every ship would consist of hydrogen, and to some degree of carbon/aluminum/lithium. Other elements would have trace mass compared to ship total mass.

I'm not talking about how industrialization would change texture of visible side of the Moon, only asking about visible perception of the size of the Moon and how huge would be consequences of building 1 billion of such massive ships on Earth ecology("tides" might not be the perfect choice of words, but Moon affect see level due to gravitational influence, please excuse my English).

76.64.30.242 (talk) 03:47, 18 June 2011 (UTC)

The Moon's mass is 7×10²² kg. Your ships mass only 5×10¹⁶ kg, and hence they would have essentially no impact on tides or Earth ecology. Dragons flight (talk) 04:40, 18 June 2011 (UTC)

Even if we would build 100 billions of such ships (lower estimate of number of starts in Milky Way), we would still get 5×10¹⁸ kg vs 7×10²². Am I correct? So that mean building 100 billion of starships each 50 000 tons would still barely affect Moon(in terms of size and diameter), in fact it would consume only less then one thousands of Moon mass? Do I understand yr calculations correctly? 76.64.30.242 (talk) 04:58, 18 June 2011 (UTC)

The moon has that much hydrogen? Plasmic Physics (talk) 05:24, 18 June 2011 (UTC)

I think it should have to have that much. If building those ships consume only 0.1% of Moon mass... But not sure. 76.64.30.242 (talk) 16:00, 18 June 2011 (UTC)

You might be interested in s:Advanced_Automation_for_Space_Missions. (I faintly remember there was once even a wikipedia article on that, but if so it has probably been deleted for political correctness or something like that.) 5BYv8cUJ (talk) 10:58, 18 June 2011 (UTC)

Question: How would that article be politically incorrect?

Question: Since when does wikipedia delete articles for being politically incorrect?

Dauto (talk) 19:36, 18 June 2011 (UTC)

You might be interested in Mogis. 5BYv8cUJ (talk) 20:47, 18 June 2011 (UTC)

The article you are linking to was only deleted on the German wikipedia which is well known for it's strict and controversy inclusion policy which as is most important in this context, rather different from the English wikipedia one. You appeared to be referring to the deletion of an article on the English wikipedia earlier so the policy of the German wikipedia is irrelevent to this discussion.

Your confusing and unsourced claims not withstanding, I find zero evidence we ever had an article on Advanced Automation for Space Missions. There is however extensive discussion at Self-replicating machine#Advanced Automation for Space Missions and Clanking replicator#Advanced Automation for Space Missions. There is brief mention in Asteroid mining#Self-Replicating Machine for material extraction. And evidentally the public domain I presume NASA study report from wikisource was used as the original source while writing parts? of Powder metallurgy and Cold welding and is used as WP:RS in Self-replication. Rather a lot of usage and mention for something we supposedly 'deleted for political correctness' which as 5BYv8cUJ pointed out doesn't even make sense (what's politically incorrect about it?).

Nil Einne (talk) 06:21, 19 June 2011 (UTC)

Answer to your second question: Since when does Wikipedia editorially trash formerly well-written articles for purposes of censorship and ban users such as myself for attempting to revert the damage caused in this manner? I tell you from personal experience, the commie WikiMafia (what the hell, no article?) has been doing this for a year or more! 67.169.177.176 (talk) 20:31, 18 June 2011 (UTC)

User:Paul Siebert has only ever been blocked once, for violating a 1rr on Mass killings under Communist regimes (not the article you linked to). If an article is under 1rr by arbcom restrictions (including discretionary) or by comunity consensus, it is a hardline rule with few exemptions. Nothing to do with censorship. If you add stuff to an article multiple times against multiple people removing it you will also break the 1rr. If you are unfamiliar with this, I suggest you read up on policy. The reason of course is to encourage discussion on a collaborative encylopaedia rather then blind edit warring which usually benefits no one. In fact, from my experience a lot of the time those who will accuse others of censorship when they remove something they want in the article and so are willing to break 1rr (or 3rr) will themselves be quite willing to do the same when it comes to adding content they do want. Or in other words a lot of the time the problem arises because of users inability to put aside their strong POV and to colloborate which will mean they are both willing to 'censor' content as well as add 'unwanted' content.

Incidentally, the 1 and only block for User:Paul Siebert was less than a year ago. Also 5BYv8cUJ and Dauto was referring to the deletion of articles which is a different thing from the removal of content from an article which is not delete. If you didn't even understand that, perhaps it explains any problems you may have had in collaborrating.

P.S. From further research the 1rr at Mass killings under Communist regimes arises from the well known Eastern European area. Anyone who has ever dealt with that area or looked at the infamous mailing lists knows it is a hell hole. Also I'm even less surprised User:Paul Siebert has had problems before. He? seems to think that 1rr means whoever has the most users 'wins' because they have greater numbers but while that may make mathematical sense, it makes no sense for anyone who has any understanding of the nature of wikipedia particular trouble articles under arbcom restrictions and high scrutiny. In reality if it ever comes down to that the article will quickly be locked and the participants in such a mass edit war will probably all be banned since 1rr is not and never a right and people who think it is or that it will be treated like one clearly don't understand how things work. Ironically though, User:Paul Siebert himself was clearly aware at the time that 1rr doesn't actually function to allow censorship since he's clearly aware people from either 'side' can be blocked.

Nil Einne (talk) 06:21, 19 June 2011 (UTC)

Just to clarify: User:Paul Siebert is not my wiki-profile (is there such a word?), but actually the one who had trashed the article Extermination through labor and then got me blocked when I tried to revert his vandalistic edits (that was a few days, maybe a couple weeks before that other flap with the article Mass killings under Communist regimes). Anyway, here's what happened: the article Extermination through labor used to have two main sections, one discussing the Nazi concentration camps (which still exists substantially unchanged), and the second one discussing the Soviet gulags (which used to be titled "In Communism" -- analogously to the first section title "In Nazism" -- but has been changed to "Controversial cases"). What Paul Siebert did was, he changed that second section by deleting information (even direct quotes from WP:RS) that substantiated the assertion that extermination through labor was taking place in the gulags, and instead added a bunch of sources that questioned and/or denied that assertion. Naturally, when I saw this I totally blew up (after all, several people from my own family had been repressed by the Soviets in various ways) and tried to revert it (unsuccessfully). I still hold a grudge against Siebert -- not because he unjustly got me blocked, but because he did so in the process of advancing an ideology that has caused untold pain and suffering in many countries around the world -- and in fact, if I ever get around to starting an alternative wikipedia of my own (for which I have tentative plans) and he joins it, I will consider preemptively putting a topic ban on him editing any article that has to do with Marxism.

As for the difference between deleting articles and removing content from articles without deletion, of course I understand this full well. The reason why I brought up the matter with Extermination through labor is not to try to somehow conflate the two, but to illustrate my point that Wikipedia does in fact carry out censorship for political reasons. 67.169.177.176 (talk) 21:00, 20 June 2011 (UTC)

This isn't the right place to talk about this (meet me at the talk page); in brief, I think there was a rationale for focusing the article, but it is important not to abandon the goal of making an article to cover all such abuses including workhouses and Jim Crow. Wnt (talk) 01:15, 21 June 2011 (UTC)

Workhouses and Jim Crow did not involve any attempts to exterminate people, unlike the gulag. Don't you understand the difference between just plain forced labor (which is still wrong) and extermination through labor? 67.169.177.176 (talk) 05:03, 21 June 2011 (UTC)

Certainly the workhouses had that overall intent; if the English had figured out a way to make sausage out of the Irish and the poor there wouldn't be one left today. Admittedly Jim Crow was the brainchild of people who knew how to keep slavery going for extended periods, but the system had considerable tolerance for casualties, and calling that "accidental" is beneath us. Wnt (talk) 17:10, 22 June 2011 (UTC)

Haven't you even READ the articles you linked to, dammit?! I have, and in the article Workhouse it DOES NOT say anything not just about "extermination", but even about any kind of excessive mortality! On the contrary -- it CLEARLY SAYS that the food was usually "nutritionally adequate" -- NOT something that would be the case if you set about to work people to death! And the ONLY THING that Jim Crow had in common with slavery is that both were designed to keep blacks in a degraded position -- Jim Crow wasn't even a system of forced labor, but rather a system of racial discrimination, and if anything it would in some cases prevent blacks from gaining employment, rather than forcing them to work! Quit making up stuff out of your head and passing it off as historical facts, will you?!?! 67.169.177.176 (talk) 21:24, 22 June 2011 (UTC)

Thank you! Looks interesting. 76.64.30.242 (talk) 16:01, 18 June 2011 (UTC)

Why would we want to do that? Cuddlyable3 (talk) 12:57, 18 June 2011 (UTC)

Maybe if we have to evacuate all of mankind from Earth for some unforeseen reason (nuclear war, alien invasion, etc...) 67.169.177.176 (talk) 20:33, 18 June 2011 (UTC)

Maybe the hydrogen could come from hydrogen-alpha from the Sun. ~AH1 ^(discuss!) 15:10, 18 June 2011 (UTC)

?? I'm assuming that's meant as some sort of joke...? Hα (hydrogen-alpha) is a particular type of red light emitted by excited-state hydrogen atoms; it isn't a type of hydrogen. TenOfAllTrades(talk) 15:51, 18 June 2011 (UTC)

The fusion proposed for Project Daedalus can't do with Hydrogen (H¹) but needs Deuterium. 5BYv8cUJ (talk) 15:57, 18 June 2011 (UTC)

I know, but by the time we would seriously talking about mass production of star ships, fusion technology should be perfectly possible with ordinary hydrogen. Reaction is harder to archive, but fully possible. 76.64.30.242 (talk) 16:11, 18 June 2011 (UTC)

p+p-reactions depend on the weak force and therefore are very slow. I guess there are many "cheaper" alternatives. You might be interested in Astrochicken (as an idea, not to take it literally). 5BYv8cUJ (talk) 22:09, 18 June 2011 (UTC)

Astrochicken idea do outshined by what is known in my language as Von Neumann probes. Closest article here - Von Neumann probes. It is much easier to imagine them, but IMHO synergy/composite idea, when self replicating starships used for first couple generations, or even first few dozen generations, and then model switch to simple "build a single starship" for every star system out there would be more efficient, both in terms of complexity and in terms of speed of exploration. My current understanding (we talking about very distant future, like 70 years from now), there would be more economical to build not a Von Neumann probe per se ("just" a single one!), but instead robotic based industry on Moon or Eris, and use that body as a base to build a billion, or 5 hundreds billions probes to target every star system in Milky Way. If for any reason that would not be possible, then create similar base on nearby Alpha Centauri or any other nearby planetary system. And use it for mass production. But it looks like potential damage to Moon would be so negligible, thus Eris or close-by star systems do not have to be targeted. Not to mention trillions of bodies in Oort cloud... My original question was - how damaging would be such activity to the Moon? Hopefully no one cares about Eris. Seems that Moon still be pretty much intact after massproduction of billions of starships. Anyhow, here is science paper that was exploring different strategies of Milky Way exploration: http://www.rfreitas.com/Astro/ComparisonReproNov1980.htm Hope you find it interesting. 76.64.30.242 (talk) 01:51, 19 June 2011 (UTC)

Plenty of reasons possible, including but not limited to exploration of our Galaxy. Imagine NASA thousand years from now wanting to send probes to each star in Milky Way. Was wondering how big loss of mass Moon would suffer if matter would be taken solely from it. 76.64.30.242 (talk) 16:07, 18 June 2011 (UTC)

Seven people per ship? μηδείς (talk) 02:15, 20 June 2011 (UTC)

You migth be interested in Golgafrincham. 5BYv8cUJ (talk) 18:28, 20 June 2011 (UTC)

50,000 tons is about 1/2 that of a US aircraft carrier, so these must be ultra-luxury yachts. Googlemeister (talk) 13:59, 20 June 2011 (UTC)

Space telescopes

--58.174.69.136 (talk) 06:39, 18 June 2011 (UTC)How can people using Space Telescopes work out details like the atmospheric composition of a planet 30 light years away? How do they achieve such amazing resolution and sensitivity?58.174.69.136 (talk)

I think that feat has not been completed yet. read spectral lines to understand how that can be done. Dauto (talk) 07:19, 18 June 2011 (UTC)

Here's an example of detecting Oxygen on an exoplanet approximately 150 light years away. http://www.spacetelescope.org/news/heic0403/ Pretty good resolution and sensitivity I believe. — Preceding unsigned comment added by 101.169.7.177 (talk) 09:55, 18 June 2011 (UTC)

Accuracy of Altitude measurements

When the "height above sealevel" of somewhere like Mt Everest is given, what exactly is the reference system used to compare sealevel and altitude? Could it be "distance from the centre of the earth"? In that case sealevel must have a pretty wide range of "distances from the centre of the earth" with the earth being the shape it is? (ie bulged out at the equator etc). Is the centre of the earth an easy thing to define? I assume earth-orbiting satellites travel around the "centre of mass" of the earth, so radar altimeter measurements would use that as their reference point? Is it possible to tell if Pacific islands like Kiribati are "sinking" (as in getting closer to the centre of the earth) or suffering from local increase in sealevel? I know this is a lot of questions, but any answers or links to appropriate reading would be much appreciated — Preceding unsigned comment added by 58.174.69.136 (talk) 07:08, 18 June 2011 (UTC)

These days points of altitude are referenced from the World Geodetic System 86. Satellite interferometry can even measure continental drift of a few centimetres per year. --Aspro (talk) 07:17, 18 June 2011 (UTC)

What you ask is a major surveying challenge on which whole books have been written. The idea is to work out where the sea level would be close to the mountain and then work out the elevation from that. Graeme Bartlett (talk) 11:03, 18 June 2011 (UTC)

The world's tallest mountain in terms of the greatest distance between the Earth's centre and the mountain's peak is Mount Chimborazo. As for Pacific nations such as Kiribati and Tuvalu, they are being innundated because of current sea level rise. When land actually drops and sea level stays the same, this is subsidence but the result is the same: saltwater intrusion. ~AH1 ^(discuss!) 15:07, 18 June 2011 (UTC)

See the article geoid, which I believe describes what Graeme Bartlett is referring to. The geoid is a mathematical description of a surface which would coincide exactly with the mean ocean surface of the Earth. The height above sealevel is calculated relative to the geoid. --NorwegianBlue ^talk 16:26, 18 June 2011 (UTC)

In the last few decades mountaineers and geographers have been able to use the Global Positioning System to determine the geometric height of mountains and other landmarks of interest. Prior to the advent of the GPS, measurements were made using pressure altimeters. The datum was an assumed air pressure of 1013.25 hectopascals, as specified in the International Standard Atmosphere. This arrangement was sufficiently accurate for the time, but is nowhere near as accurate as the modern GPS. Dolphin (t) 12:20, 19 June 2011 (UTC)

Lunar eclipse

Ok, so I imagine this will be one of those "stupid questions", but nonetheless: Recently there was a lunar eclipse with a lot of media attention. As I understand it, a lunar eclipse happens when the alignment of Earth's shadow in front of the Sun obscures, or partially obscures, the visible moon. So what is the difference between a lunar eclipse, and the phases of the moon? Don't we often see the shadow of the Earth affecting visibility of the moon; i.e a crescent moon, half moon, etc.? Quinn ^{❀ BEAUTIFUL DAY} 07:10, 18 June 2011 (UTC)

The phases of the moon have nothing to do with the earth's shadow. They are simply the result of where the moon is in relation to the sun and the observers, us. Think about looking at a ball which is lit only by a single light off to one side. The lit up part you see is equivalent to a phase of the moon. The article Lunar phase may help, but it looks a bit heavy to me. HiLo48 (talk) 07:16, 18 June 2011 (UTC)

Shit. My first instinct was correct: It was a stupid question. Phases of the Moon specifically states that the lunar phases are not a result of Earth's shadow. Good grief! But in my defense, Lunar eclipse really offers no help with this question. Quinn ^{❀ BEAUTIFUL DAY} 07:19, 18 June 2011 (UTC)

An eclipse of the Moon is always the Earth's shadow passing across a full Moon. Cuddlyable3 (talk) 12:49, 18 June 2011 (UTC)

The phases of the Moon are caused by the Moon's shadow, so to speak, just like nighttime on Earth is caused by the other half of Earth blocking the Sun's light. During a total lunar eclipse, the Earth's umbra obscures the entire Moon. What usually happens during a full Moon instead is that the Moon's tilt above or below the Earth's ecliptic is too far away from any part of Earth's shadow during the greatest point of Full Moon that the Moon completely misses the shadow and you get no eclipse; conversely, during a solar eclipse, the shadow cast by the Moon lands on the Earth when it would usually miss the Earth completely. ~AH1 ^(discuss!) 15:04, 18 June 2011 (UTC)

And, as far as observations go, a lunar eclipse varies from a change in phase in two ways:

1) It's much quicker, lasting only minutes instead of about 28 days.

2) Since the radius of the Earth is larger, the radius of the shadow cast on the Moon is larger during a lunar eclipse. StuRat (talk) 23:03, 18 June 2011 (UTC)

Lunar eclipses can last a few hours. Dauto (talk) 16:06, 19 June 2011 (UTC)

Another way of thinking about the difference is this: Lunar phases involve only 2 celestial bodies, the Moon and the Sun. We here on Earth are simply observers, and we could just as well be observing from Mars (assuming we had a telescope that could let us observe from that distance). But a lunar eclipse involves 3 bodies: the Moon, the Sun and the Earth. The Earth's shadow on the Moon is a fundamental part of this scenario. -- Jack of Oz ^{[your turn]} 23:10, 18 June 2011 (UTC)

Kill or capture a household fly

How can I kill or capture an irritating fly in my living room? Whacking it with a rolled-up newspaper would damage things, and I always miss. Going to buy some fly paper would take too long. In the past I captured a fly alive by covering it with a very large plastic bag, but I havnt got a large enough bag, the fly is very agile, and the clutter in the room makes it more difficult. Thanks. 92.29.126.21 (talk) 11:59, 18 June 2011 (UTC)

You must disable it. You can buy a charged racket and wave to those fly. When the fly pass though those grid, its nervous system will temporary disabled.Nilman (talk) 12:31, 18 June 2011 (UTC)

Take a fairly large, preferably see-through container which has, or in which you can create, a small entrance aperture: an empty 2-litre soft drinks plastic bottle might work, or an old mesh meat cover.

It helps if you can make the entrance convex to the inside of the container, perhaps by making and fitting an open ended paper tube in it. In the case of the plastic bottle, you could cut off the top just below the shoulders, reverse it to sit in the top of the main body, and tape it in place.

Put something smelly and attractive to the fly into it.

Wait until the fly enters the container, then close the aperture. Because the entrance/exit is small, difficult to find and (depending on the created configuration) difficult to negotiate from the inside, the fly will not have time to escape even if it sees you coming.

This is an adaption of the old method, common in freshwater angling, of knocking a hole in the recessed conical bottom of a wine bottle, baiting the closed neck, submerging the apparatus in a stream, and using it to catch small fish for use as bait for larger fish. {The poster formerly known as 87.81.230.195} 90.201.110.145 (talk) 12:33, 18 June 2011 (UTC)

Butterfly net. Cuddlyable3 (talk) 12:43, 18 June 2011 (UTC)

I can think of two ways. One is to create a cone-shaped container with some meat or other aromatic food in the middle, and a small hole at the bottom through which the fly can fly in, and hang it up in the room. The fly is unlikely to fly underneath in order to get out. Also, if you have a see-through curtain in any room, try to wait until the fly gets close to the window there. Trap the fly between the curtain and the window, and do whatever you need to do next. ~AH1 ^(discuss!) 15:00, 18 June 2011 (UTC)

What I do is wait until the fly sits on a wall, get a drinking glass and a piece of paper large enough to cover the glass. Then put the glass slowly over the fly. You then gently move the paper betweeen the wall and the glass, this pushes the fly into the glass. You then take the covered glass outside and release the fly. Usually this takes me one or two minutes per fly. If the fly is flying around a lot, then this won't work well, but then you can move the fly by making the room dark, open a door to another room and put a light on in that room. The fly will then fly toward the light and thus leave the room. Count Iblis (talk) 15:32, 18 June 2011 (UTC)

A flyswatter

Flyswatter. 75.41.110.200 (talk) 15:45, 18 June 2011 (UTC)

Eventually a fly goes to the light in the window. Given drapes, shades, etc., it is difficult for it to get back, and easy for misfortune to befall it. But when I was younger my pleasure was to do battle with the fly using a can of Lysol (essentially spray alcohol) and a lighter. It only harms the wings, and then the rest of the fly is yours to experiment with at your leisure. I think I blame Dragonriders of Pern for that. ;) Wnt (talk) 18:35, 18 June 2011 (UTC)

No-one's mentioned just squirting it with bug spray yet? Flies are very, very quick - but even they struggle to dodge an aerosol spray (most of the time anyway). --Kurt Shaped Box (talk) 18:46, 18 June 2011 (UTC)

Once upon a time some brilliant person cogitated very deeply on this very problem, and came up with a brilliant and creative solution. It is known as a "flyswatter". Looie496 (talk) 18:55, 18 June 2011 (UTC)

Incidentally, the reason a flyswatter works better than a newspaper is that it has holes to let the air pass through. Thus the flyswatter moves faster, due to the lack of air resistance, and there's no whoosh of air in front to blow the fly out of the way.

Another approach I've had luck with is to open a window (yet leave the screen in). The fly will go to the screen, then I close the window behind it and leave it closed until the fly dies (a few days, typically). I usually "mark" the window in some way as a reminder not to open it too soon. I have one trapped right now, as a matter of fact, and a toilet paper roll tied to the pull string for the blinds is my reminder.

I suggest you close doors to restrict the fly's movements, and then open all the windows it can reach, to maximize the chances of catching it quickly. Also, a warning on fly paper, it's very messy, getting brown glue all over anything it touches. StuRat (talk) 19:28, 18 June 2011 (UTC)

That sounds like a lot of trouble to kill the fly rather than just letting it fly away outside. Are fly corpses useful? Rckrone (talk) 19:57, 18 June 2011 (UTC)

"Letting it fly outside" involves leaving a door or window open (without a screen) until it decides to leave on it's own, by which time several more insects are likely to have flown in. StuRat (talk) 22:29, 18 June 2011 (UTC)

Depending on the species of fly, a flyswatter may not be effective unless the fly is at rest on a surface. I'm not entirely sure what species of fly this is (it's smaller than a bluebottle, medium-sized-ish) - but there's one in the UK that's very good at evading attempts to swat it in mid-air. FWIW, a vacuum cleaner hose can be good against flying insects - I once sucked up 30+ wasps from my living room (nest was in an air vent) with the Dyson... I don't see why it wouldn't work on flies. --Kurt Shaped Box (talk) 20:36, 18 June 2011 (UTC)

I've also used a vacuum cleaner on stinging insects. The big advantage is that they don't see it as an attack, so don't get angry and try to sting you, unlike trying to swat them. However, this doesn't apply to flies, and flies are also often faster with a more chaotic flight, so catching them this way may not work. StuRat (talk) 22:39, 18 June 2011 (UTC)

Why don't you just try an exploit, doing something useful with it? No, no, thanks, don't feel worthy enough for that myself, thank you all the same. 5BYv8cUJ (talk) 19:47, 18 June 2011 (UTC)

There are self-replicating robots available that catch flies and use them to make copies of themselves. Unlike sprays, fly swatters, etc. they are free of charge.Count Iblis (talk) 02:51, 19 June 2011 (UTC)

True. AndyTheGrump (talk) 03:01, 19 June 2011 (UTC)

You might want to make sure it's not The Fly. "Be afraid. Be very afraid." HiLo48 (talk) 03:00, 19 June 2011 (UTC)

Or better yet, the 1950s version with David Hedison while he was still known as Al. "HELP ME! HELP ME!"[12] We also need a companion to the flyswatter pic: The Far Side cartoon called "the last thing a fly ever sees."[13] ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:46, 19 June 2011 (UTC)

As a practical matter, one trick is to position your hands apart and a few inches above the fly. As soon as it moves, clap your hands together, and there's a reasonable chance you'll get it. Then, of course, wash up. You don't know where they've been (although you can guess). ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:55, 19 June 2011 (UTC)

Here's a technique my father taught me. Take a long thin pole (bamboo garden poles for keeping plants upright work well) and a length of elastic cord. Fix the end of the elastic to the end of the pole, stretch the elastic back along the length of the pole and hold it against the pole with one hand. Stand back from the fly and aim the pole at it (you can get quite close if you go slowly). Once you are lined up just let go of the end of the elastic. It's the flyswatting equivalent of a sniper rifle. Equisetum (talk | email | contributions) 07:51, 19 June 2011 (UTC)

We've just got rid of a fly in our living room by opening the window and waiting for it to head towards it. Is that not an option in this case? --TammyMoet (talk) 10:12, 19 June 2011 (UTC)

Or you can try to do brain surgery on a fly to turn it into a remotely controlled spying machine. You can e.g. let it fly into the CIA headquarters without anyone noticing it... Count Iblis (talk) 14:59, 19 June 2011 (UTC)

Gotcha! It was you who sent that spy fly that Obama swated! (This is a totally new aspect of a no-fly zone.) 5BYv8cUJ (talk) 15:08, 19 June 2011 (UTC)

Back in the early 90s, when they were talking about a no-fly zone in Iraq, Jay Leno said, "What we really need is a no-fly zone around Denny's!" ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:12, 19 June 2011 (UTC)

Bit of a long shot on having the right materials around, but this method always worked when I was a kid: Spray Starch. Hit the fly with a short burst; it will drop out of orbit within two seconds when the starch dries. Advantages: the product, if you have it, is cheap; you can expel the fly with no harm to either party, if that's a concern; and unlike many other products, the overspray does not stain and wipes up if needed with a damp cloth.

DaHorsesMouth (talk) 01:19, 20 June 2011 (UTC)

Plus, it's nontoxic (unlike bug spray). 67.169.177.176 (talk) 04:11, 20 June 2011 (UTC)

Does Gamma Ray travels slower than Light Speed?

Those are from Wikipedia:Gamma ray burst: "gamma-ray bursts are thought to be highly focused explosions, with most of the explosion energy collimated into a narrow jet traveling at speeds exceeding 99.995% of the speed of light." But ALL electromagnetic wave travels as a constant speed in vacuum. Gamma ray is a kind of electromagnetic wave. Gamma-ray travels at 99.995% of the speed of light. So there's a contradiction, Why?Nilman (talk) 12:16, 18 June 2011 (UTC)

I don't really know but if you think of the "gamma-ray burst" not as the gamma rays but as the explosion that accompanies and/or generates them, this would resolve the paradox. 5BYv8cUJ (talk) 12:40, 18 June 2011 (UTC)

As 5BYv8cUJ says, the explosion itself is of matter: just how this is partially converted into gamma rays is not yet properly understood, and is the subject of ongoing research. See the Emission mechanisms section further down in the article from the quote, and the longer and more detailed article Gamma-ray burst emission mechanisms to which it links for current theories. {The poster formerly known as 87.81.230.105} 90.201.110.145 (talk) 12:46, 18 June 2011 (UTC)

That's the speed of the jets. The gamma rays move at the speed of light. Dauto (talk) 19:29, 18 June 2011 (UTC)

Thank you.Nilman (talk) 09:51, 19 June 2011 (UTC)

Did the military have mobile phones?

In an episode of the 1960s series I Dream of Jeannie, Don Rickles played a senior military officer who was putting the astronauts through rigorous military training on a remote area of what I believe was a military base. He stayed in touch with the people in charge using a telephone in a bag of some kind. It looked like regular phones looked back then, and it had a wire connected to something. The mobile phone article doesn't seem helpful.Vchimpanzee · talk · contributions · 16:19, 18 June 2011 (UTC)

Our article on field telephones describes these devices. Looie496 (talk) 18:06, 18 June 2011 (UTC)

When I think of field phones I always imagine some pioneers laying wires. I guess by the sixties these would have been replaced by wireless walkie-talkies. But still without any possibility to play pac-man.5BYv8cUJ (talk) 18:42, 18 June 2011 (UTC)

Actually, two-way radios first appeared during World War 2, but they were big and heavy (typically taking up a whole standard-issue Army backpack). 67.169.177.176 (talk) 20:38, 18 June 2011 (UTC)

Yes, so only a few soldiers were assigned to carry them, meaning anyone isolated from those soldiers was out of communication with everyone else. Also, since there weren't many, they could all be destroyed in battle, cutting off communications with the entire group. StuRat (talk) 22:35, 18 June 2011 (UTC)

The Motorola SCR-300 was used during WWII - it weighed 32 pounds (15 kg) or 38 pounds (17 kg) depending on the battery and had a range of 3 miles (4.8 km) with the long aerial. BTW the website olive-drab seems good for this sort of info, it's where Google led me. CS Miller (talk) 09:58, 19 June 2011 (UTC)

Coming back to the OP's question, the 1968 AN/PRC-77 Portable Transceiver is about the size of an ammo box, its externally identical predecessor AN/PRC-25 Portable Transceiver was produced in 1962. However, the TV series may have shown Korean-War era equipment not Vietnam-War era, which would be the AN/PRC-10 -- CS Miller (talk) 10:08, 19 June 2011 (UTC)

Wireless telephones were first invented about a century ago, but the evolution of their practical usage was rather slow until the last 20 years or so. ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:40, 19 June 2011 (UTC)

Thanks. I'll look at the other sites tomorrow. I'm sure field telephone is what I was looking for, though I think the Mobile phone and History of mobile phones articles (I forgot to list that second one above) should be updated with this informtion. I'm not sure just how to insert it since ther couldbe some overlap with radiophony. I don't want to just have two separate paragraphs on two topics that could be related.Vchimpanzee · talk · contributions · 18:23, 19 June 2011 (UTC)

Hitting cows on their noses

If you hit an imposing cow on the nose with a stick or a fist, will it likely turn more aggressive or turn and leave? --2.216.135.118 (talk) 19:25, 18 June 2011 (UTC)

Depending on the circumstances and the cow, it might do either. However, since "more agressive" may include seriously injuring or killing you, which a cow can do quite easily, you ought to avoid getting into such close contact with cows in the first place until you know what you're doing. In the UK, one or two farmers - who do know what they're doing - are nevertheless killed by cows every year, as sometimes are country walkers who venture into fields of cows and somehow annoy one or more of them (usually by having a dog with them). {The poster formerly known as 87.81.230.195} 90.201.110.209 (talk) 19:47, 18 June 2011 (UTC)

Cows become very aggressive when they have their young calves with them. They stampede and/or trample people to death. So stay away from cows with calves. 92.29.112.181 (talk) 19:54, 18 June 2011 (UTC)

Cows are inquisitive, and don't normally attack humans (though a bull might), but there are three situations when they might be dangerous:

1. When a person is holding a dog (which the cow sees as a threat), so it is always wise to allow a dog to look after itself in an emergency.

2. When they panic and "stampede", trampling anything that gets in the way, so move slowly to avoid frightening them.

3. When anything gets between a cow and its offspring (in common with most mammals, including humans).

A stick might help if a cow is becoming over-inquisitive, but will not make any difference to a panicking cow and probably not to one protecting its calf. Dbfirs 06:45, 19 June 2011 (UTC)

You forgot (4): When someone purposely annoys them by persistently waving a piece of cloth in their face. 67.169.177.176 (talk) 00:30, 20 June 2011 (UTC)

What's an "imposing" cow? One that always shows up right at suppertime? ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:38, 19 June 2011 (UTC)

My wife has been in the "dog irritates cows that have calves nearby" while walking in one of those preserves in the East Bay, California. It's times like that that city slickers like us realize exactly how large a cow is. Fortunately they managed to talk their way out of it. --Mr.98 (talk) 18:36, 19 June 2011 (UTC)

I'm glad to hear that those cows were intelligent enough to respond to a reasoned argument from your wife and dog. I never seem to be able to get cows to understand what I am saying, but they do seem to respond to a calm tone of voice. Dbfirs 21:21, 19 June 2011 (UTC)

Bovines have horns, and they know how to use 'em. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:41, 19 June 2011 (UTC)

One tip i learned from a farmer once when I was helping him feed his cows once was whenever you are near cows, never get between a cow and anything solid: like a barn, fence, trees, the truck, another cow. Cows don't really know their size and don't take time to consider what they might be squishing when they move around. Vespine (talk) 01:22, 20 June 2011 (UTC)

I've heard they could even smash up a small plane (like Amelia Earhart's Lockheed Vega) just by leaning on it. 67.169.177.176 (talk) 04:15, 20 June 2011 (UTC)

Here we have "Dangerous Cows" for your reading pleasure. Bus stop (talk) 12:19, 20 June 2011 (UTC)

Woman killed by cow: http://www.desmoinesregister.com/article/20110619/NEWS/110619007/Update-Family-says-woman-died-protecting-toddler-from-cow?odyssey=tab%7Ctopnews%7Ctext%7CFrontpage μηδείς (talk) 16:32, 20 June 2011 (UTC)

With all due sympathy to the family, I love the description of the incident - "The cow hit her with its head and her heart stopped." That, folks, is how to write English sentences. Tevildo (talk) 18:35, 20 June 2011 (UTC)

Relative pulling power of one horse

I remember being told at school (decades ago) that there was an experiment or comparison of horse pulling powers done about 200 - 300 years ago, which showed relative powers (if I recall correctly) of: - horse can carry a few hundred pounds on its back (this was pre-metric) - pull about a ton in a cart on decent road - pull 8 tons on a metal rail - pull 70 tons in a canal boat

Is this correct? Is there a specific experiment or something that proved this, or did the knowledge just accumulate over time? — Preceding unsigned comment added by J987 (talk • contribs) 20:44, 18 June 2011 (UTC)

See Horsepower. James Watt is _reputed_ to have carried out the experiment (in 1782) to determine a suitable unit of power for his steam engines, but whether his results (as opposed to the magnitude of the unit) are reliable is a matter of debate. Tevildo (talk) 21:56, 18 June 2011 (UTC)

In the first case, the horse is actually carrying the weight, while in the rest, assuming level ground and no air or water flow, all that must be overcome is friction. In the cart and rail cases, there is a static friction to overcome to get things started (they must assume this to be worse for the cart). In the boat case there is none of that, and only the fluid resistance of the air and water (which grows with speed). Thus, to move the boat very slowly should require almost no effort, assuming no winds or water current. In reality, I'd expect how much a horse can haul to vary dramatically depending on the horse, lubrication of the cart and train, condition of the road and track, and the winds and water currents. StuRat (talk) 22:47, 18 June 2011 (UTC)

You don't have to do any work to carry a weight unless you are lifting it. As long as the horse's back doesn't rise and fall too much as it moves, the energy required probably isn't much greater than overcoming friction in the other scenarios. (There may be some energy required to maintain the muscle tension required to hold up the weight, but that's biology not physics, so I don't know anything about it!) --Tango (talk) 22:55, 18 June 2011 (UTC)

Only in the simplifications of physics that are applied for students. In reality, you go and carry 50 lbs around on your back all day and tell me that isn't work. Googlemeister (talk) 13:24, 20 June 2011 (UTC)

It gets complicated. Since horses don't have wheels on them, they need to to lift their legs to move. The more weight distributed on each leg (in addition to their own weight), the more work this requires. And they don't get all this energy back when they put the leg back down again, so energy is lost. Depending on how the weight on their back is positioned, they may be able to reposition it a bit by their movements, and thus have less on each leg as they lift it. This also would be affected by the type of walking or running done by the horse, as each has different legs off the ground at once. Converting all this to physics formulae would be quite an effort. StuRat (talk) 23:09, 18 June 2011 (UTC)

They are only lifting the leg, so only the weight of the leg matters. The weight of the load will inevitably shift to the other legs, but that doesn't take energy. The weight of the load is only important if you actually increase the height of the load (which may happen slightly due to way the horse moves and will obviously happen if the horse goes up hill). --Tango (talk) 00:42, 19 June 2011 (UTC)

Why would the weight not matter on a level field? Certainly to support a weight, the horse must meet this weight with opposite and equal (and constant) force, otherwise the load would just fall to the ground? Anecdotally, I can fairly easily hold a hundred pounds on my shoulders. I can also easily walk 15 miles. It would be extraordinarily difficult for me to walk 15 miles carrying a hundred pounds on my shoulders, but fifteen miles with fifteen pounds would be much more doable. Why would a horse be different in that regard, other than the obvious fact that a horse can carry much more than I can? Falconus^{p t c} 05:04, 20 June 2011 (UTC)

Edit: Part of that is that it would be extremely difficult, indeed I rather doubt that it's something I could to to hold a 100 pounds for three or four hours, regardless of distance walked. Falconus^{p t c} 05:10, 20 June 2011 (UTC)

Yes, the load makes a big difference in practice, much more than would be expected from the simplified physics of moving a load horizontally. As mentioned above, some of the work goes into raising and lowering the load an inch or two with each step, but probably more of it goes into the chemical energy expended in the muscles that have to deal with much higher tensions than normal. Dbfirs 18:45, 20 June 2011 (UTC)

June 19

Iraqi National Oil Company

Dear Wikipedia,

Why is there nothing on the Iraqi National Oil Company since 1987 on your page (http://en.wikipedia.org/wiki/Iraq_National_Oil_Company)?

Are they a publicly traded company?

How would one invest in INOC?

Thanks,

50.15.18.118 (talk) 00:09, 19 June 2011 (UTC)

The event in 1987 it mentions is it merging with the oil ministry, so it ceased to exist as an independent company at that point. That's why the article doesn't go any further. --Tango (talk) 00:38, 19 June 2011 (UTC)

The page on Iraqi Oil Ministry isn't exactly stellar either. There must be some company that owns Iraq's oil... 50.15.18.118 (talk) 07:17, 19 June 2011 (UTC)

Why do you think it can't be state-owned? --TammyMoet (talk) 10:11, 19 June 2011 (UTC)

The oil of Iraq is owned by the Iraqi people. The Iraqi National Oil Company, which is one of the few government ministries that survived the recent war and overthrowal of the government, has been a state-owned corporation since 1966; in recent times, for logistics reasons, it was split into North Oil Company and South Oil Company, splitting operations on both sides of the 32.5 degree N latitude line. You cannot invest in either of these companies; they are nationalized. You can conduct business with them; but if you don't already know how to negotiate a petroleum E&P contract, Wikipedia isn't the appropriate place to learn. If you want to invest in the oil industry, you can research your favorite publicly traded integrated supermajor or oilfield services corporation, or track down one of the thousands of smaller companies that operate in Iraq; innumerable companies operate in Iraq in some capacity. Per recent developments, Shell will operate the Development and Production Service Contract for Majnoon (one of the largest fields in the region). You can learn how to invest in Royal Dutch Shell or your local Shell subsidiary, and download investment guidance, at the Shell investor-relations webpage. Keep in mind that numerous other major and minor corporations, public and private, also operate in Iraq, working side-by-side (sometimes on the same well).

It is a moot point to debate who "owns" the petroleum. It is a mineral resource. If you're new to mineral resource economics, here's a good primer, Economic Theory of Depletable Resources. Specifically in Iraq, the crude oil in the ground is "owned" by the Iraqi people, and is administered by the National Oil Company, and extracted by an authorized production company who has the equipment and expertise to do so. Iraqi and foreign companies may extract the petroleum for a fee, provided that they abide by the rules and laws of Iraq. This region has been in a war for several years, and the government has changed significantly. Consequently, the business environment is fraught with legal (and illegal) complexities - it's not really a good environment for a novice investor. Nimur (talk) 00:37, 20 June 2011 (UTC)

Lunar eclipse (why not with every full moon ?)

Why isn't there a lunar eclipse every time there's a full moon? --75.40.204.106 (talk) 00:57, 19 June 2011 (UTC)

(ec) I changed the title to distinguish this from the other lunar eclipse question a couple above this one. This question was also answered there, but, to reiterate, most times it passes behind the Earth, the Moon is either above or below the line formed by the Earth and Sun. Thus, the Earth's shadow falls above or below the Moon. Only when they happen to align does a lunar eclipse occur, or a solar eclipse if the Moon is between the Sun and Earth. StuRat (talk)

Because the Moon's orbit around the Earth is inclined by about 5 degrees relative to the Earth's orbit around the Sun. The Earth casts a conical shadow in space and the inclination of the Moon's orbit means that most of the time it either passes above or below that cone. It is only when the full moon happens at the same time as the Moon's orbit crosses the plane of the Earth's orbit that we get a lunar eclipse. --Tango (talk) 01:12, 19 June 2011 (UTC)

If the moon's orbital plane around the earth were the same as the earth's orbital plane around the sun, we would get a lunar and a solar eclipse every month. They aren't, so we only get lunar and solar eclipse pairs a couple or three times a year. ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:36, 19 June 2011 (UTC)

Although solar eclipses at any particular location on Earth would still be less common, as they are now, since, while the Earth's shadow covers the entire Moon, the Moon's shadow only covers part of the Earth. And, if the Moon stayed in the same plane as the Earth's orbit of the Sun, then those solar eclipses wouldn't ever be seen at the Earth's poles. StuRat (talk) 16:11, 19 June 2011 (UTC)

Yep. If the two orbs were in the same plane, all the solar eclipses would occur within the two tropical latitudes. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:10, 19 June 2011 (UTC)

Psychological solar heating

Consider this situation. I'm inside and can look outside through my window. It's a fairly cold day, but comfortable enough inside. While the sun's out I feel quite warm. When the sun goes in (say just going behind a cloud) after a few minutes I don't feel so warm. When the sun comes back out I feel warmer again.

Since I'm inside, the actual temperature is not changing in such a short time and the sun's radiation is not striking me in any way to warm me up (sure there may be a tiny bit of reflected radiated heat, a little bit more black body radiation coming from outside, and stuff like that, but not enough to make any noticeable difference in the course of a few minutes). So clearly, to me, there must be something psychological going on here. I'm pretty sure I'm not the only one who experiences this.

Is there a name for this phenomenon, has it been studied in any depth, and are there any likely applications of it? --jjron (talk) 10:46, 19 June 2011 (UTC)

Close your eyes. Do you feel warmth on your skin immediately sunlight strikes it? If so, you are feeling Thermal radiation by Infrared rays and it is not an illusion. Cuddlyable3 (talk) 15:36, 19 June 2011 (UTC)

I wouldn't discount reflected light as an important source of heat, specially if the ground is snow covered outside. Dauto (talk) 15:52, 19 June 2011 (UTC)

Yes, do try the simple experiment to determine how much of your perception is psychological. I suspect that both effects are measurable. Dbfirs 16:14, 19 June 2011 (UTC)

I agree that it heats you skin more than you might think. Radiant heating is an attempt to duplicate this heating method. Ideally, it could allow the occupants of a house to be kept warm without heating the home, and save lots of energy. The reality, though, is that the parts of the body hidden from the radiant heaters are chilled, making the occupants uncomfortable. StuRat (talk) 16:20, 19 June 2011 (UTC)

A friend and I pondered exactly this, many years ago after noticing the same effect. We titled it "rimduction: a mimetic transfer of heat", which is complete gibberish, obviously, but it's interesting that others have thought the same thing. Zzubnik (talk) 09:02, 20 June 2011 (UTC)

Purifying water with bleach in th UK - bleach source?

If I want to purify water with household bleach, I need to use bleach with no added perfumes or detergents. What such sources of this are there in the UK? ASDA's own brand and Domestos both seem to contain other things I don't want. I know I can buy tablets but their price iswell above their value considering the cost of household bleach. — Preceding unsigned comment added by 2.216.135.118 (talk) 11:13, 19 June 2011 (UTC)

Not a good idea. Depending on the production process there may be impurities in the bleach on a toxic level when you eat or drink the water. Why don't you use a pressure cooker instead? 5BYv8cUJ (talk) 11:40, 19 June 2011 (UTC)

If it's not a good idea, why is it recommended [here], [here], [here], [here], [here] etc...? Also, a pressure cooker is heavy, requires fuel and necessitates a long cool down period and a small bottle of bleach is/does not. 2.216.135.118 (talk) 12:49, 19 June 2011 (UTC)

If you are willing to pay for the more expensive food grade stuff then it's save. I interpreted your question the way that you intended to use normal household bleach that is intended for bleaching clothes etc. Also, in an emergency, for example a cholera outbreak, using household bleach might probably be less of a risk than drinking contaminated water. 5BYv8cUJ (talk) 13:00, 19 June 2011 (UTC)

I think you're looking for sodium metabisulphite. A proprietary brand of this is Milton, or you could try Asda's own brand equivalent. You will find this in the nappy cleaning section. Another place to look is in a home-brew shop, who will sell this as a sterilising agent. --TammyMoet (talk) 11:42, 19 June 2011 (UTC)

Thanks, but I'm looking to disinfect water for drinking rather than equipment. 2.216.135.118 (talk) 12:49, 19 June 2011 (UTC)

If it is for use when camping etc., then chlorine tablets is the easiest way carry it. Such as can be seen here: http://www.lifesystems.co.uk/psec/water_purification/water_chlorine.htm --Aspro (talk) 13:13, 19 June 2011 (UTC)

You can buy water purification tablets at any decent outdoor shop. They are specially designed for purifying water for drinking, so are probably a better choice than household bleach. --Tango (talk) 15:11, 19 June 2011 (UTC)

I never allow bleach within yards of drinking water or any crockery because I can taste it at an extremely low concentration. Use Aspro's & Tango's suggestion instead. Dbfirs 16:10, 19 June 2011 (UTC)

This is a surprising question, as all tap water in the UK is safe to drink, and indeed better quality than bottled water according to studies. If you want to purify water from a stream while out camping, then why not go to a camping or outdoor shop and buy some water purification tablets? 92.29.112.168 (talk) 18:39, 19 June 2011 (UTC)

The OP refers to North American websites, so I assume purification is required for water in that continent. The advice given refers to use of bleach in an emergency. I would prefer to find a spring or small spring-fed stream so that I could drink the water without any treatment, but I realise that this will not be possible in some areas. The human stomach is very acidic, and will kill most bacteria, and the gut will adapt to cope with many others, but water with a high bacterial content (especially some strains of E Coli) would certainly be safer after treatment, and I suppose I would learn to tolerate the taste of bleach in an emergency if the only source of water was polluted. A mixture of dilute pure sodium hypochlorite and salt (such as Milton fluid), or Campden tablets (as mentioned above) is safer than common household bleach and less unpleasant. I regularly drink untreated water from clean streams without any ill effect, and not quite all of the tap water in the UK is treated. Dbfirs 20:44, 19 June 2011 (UTC)

Tap water in North America is safe to drink and requires no further purification (I've been drinking tap water myself on many occasions and never experienced any ill effects). The websites refer to purifying water in an emergency situation (e.g. earthquake, flood, hurricane, etc.) when tap water may be unavailable or contaminated. -- An American ultranationalist 67.169.177.176 (talk) 00:52, 20 June 2011 (UTC)

Isn't Mexico part of North America? Googlemeister (talk) 13:19, 20 June 2011 (UTC)

Sorry, I didn't intend any criticism of North American treated tap water. I'm sure it is just as safe as UK "mains" water. I suspect that, as in the UK, there are areas with private supplies that are untreated. I've been drinking untreated water all my life without any ill effects. Dbfirs 07:01, 20 June 2011 (UTC)

By "private supplies" you mean your stereotypical water-well with a hand-pump on top, dontcha? In that case, chlorine tablets might indeed be needed, depending on the quality of the groundwater. 67.169.177.176 (talk) 10:16, 20 June 2011 (UTC)

BTW, if your intent was to italicize your text, the proper command for this is two single quotes one after another, like this: ''Your text'', rather than a double quote. 67.169.177.176 (talk) 10:20, 20 June 2011 (UTC)

No, I put "mains" in quotes because I wasn't sure whether Americans talk about "mains" water and "mains" electricity. Dbfirs 18:51, 20 June 2011 (UTC)

We have water mains, but I don't know what we Americans call the electrical analog. Googlemeister (talk) 20:16, 20 June 2011 (UTC)

The power grid (although this term is usually used to denote only the high-voltage lines). 67.169.177.176 (talk) 21:03, 20 June 2011 (UTC)

Thanks, I was evidently confusing the systems and I didn't need quotes at all for water mains. Do you have "mains gas" on your side of the pond? Dbfirs 06:29, 21 June 2011 (UTC)

Yes, "gas mains" is the proper term. 67.169.177.176 (talk) 11:04, 21 June 2011 (UTC)

Would it work to use chlorine to kill the bacteria, and then use a filter (as with a Brita pitcher) to trap the chlorine? ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:29, 20 June 2011 (UTC)

Activated carbon is pretty effective at removing chlorine. 67.169.177.176 (talk) 04:17, 20 June 2011 (UTC)

Bad Rupture

If someone was said to suffer from a "bad rupture" in the latter part of the 19th century - what is the exact medical term today? Apparently this person had the problem for some 2 years and there was not then (or was just new) a cure for it. Also it appears it was not life threatening, however painful. He was cured of the problem by 1900 and henceforth lived a normal life. Guesses?--Doug Coldwell ^talk 12:34, 19 June 2011 (UTC)

According to Rupture this would be Abdominal hernia. 5BYv8cUJ (talk) 12:51, 19 June 2011 (UTC)

Like The only cure for hernia is surgery. μηδείς (talk) 02:22, 20 June 2011 (UTC)

What's with the "Like"? Are we now rating our own responses? Bielle (talk) 03:37, 20 June 2011 (UTC)

Is there a matching "thumbs down"? I couldn't find one. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:42, 20 June 2011 (UTC)

In the old days (and maybe still) they used a Truss (medicine) to deal with a hernia. Not a cure, just a "keep it under control" kind of thing. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:27, 20 June 2011 (UTC)

They no longer use this because surgery is much safer now than it was back then. 67.169.177.176 (talk) 04:20, 20 June 2011 (UTC)

Yes, still. Until either surgery or death. An abdominal; hernia is a quite morbid condition. μηδείς (talk) 03:46, 20 June 2011 (UTC)

Using Nuclear Warheads for Electricity Generation

Have there been any efforts (theoretical or otherwise) to capture the energy released from a nuclear detonation and use it to produce electric power? I know that a) it's not possible (even in theory) to convert all the energy released into electricity, or even most of it as a practical matter; and b) even if you could convert, there's no easy way to store that amount of power. But couldn't you use the energy to electrolyse a bunch of water and store the hydrogen (say), or immerse the warhead in a cavern full of water and capture the steam? 24.215.229.69 (talk) 13:05, 19 June 2011 (UTC)

I don't think it has been attempted the way you described it. But the easiest way to use nuclear warheads to generate electricity is to take the nuclear fuel out and feed it into a nuclear power plant, possibly after some reprocessing. 5BYv8cUJ (talk) 13:16, 19 June 2011 (UTC)

The weapons grade uranium from South Africa's decommissioned nuclear warheads was diluted down to the concentration needed for fuel rods for the Koeberg nuclear power station. The South Africans only had 6 warheads so I'm not sure if it's a feasible for converting much larger arsenals such as the US, Russia, and China have. Their warheads are also based on plutonium which is more complicated to use as a reactor fuel. Roger (talk) 13:29, 19 June 2011 (UTC)

See Megatons to Megawatts. --Mr.98 (talk) 15:53, 19 June 2011 (UTC)

There used to be lots of mad ideas like this, for instance cutting canals or other engineering works using nuclear weapons. I think it was associated in black an white films with a stentorian voice and a huge flashing glowing giant and electricity for everyone for free and mums happily ironing shirts in bungalow houses across the nation. It would only be really worthwhile in energy terms compared to a nuclear power station if you used hydrogen bombs and no I don't think I want it thanks very much. Dmcq (talk) 13:17, 19 June 2011 (UTC)

The use of nuclear explosions for constructive purposes was explored by Operation Plowshare in the United States, and Nuclear Explosions for the National Economy (or sometimes just "Project #7") in the USSR. See additionally our article on peaceful nuclear explosions. While (as far as I know) none of these programs contemplated the direct generation of electricity from the heat and pressure of a nuclear detonation, several projects (under consideration or actually carried out) involved oil, gas, or coal recovery, the creation of natural gas storage caverns, or the creation of canals and reservoirs for hydroelectric generation. TenOfAllTrades(talk) 13:34, 19 June 2011 (UTC)

Project Gnome cross section — note "power and isotope recovery" channels above the nuclear explosion

Yes, this was directly considered during the Cold War by the United States. Project Gnome was a 1961 nuclear test carried out in part to investigate turning water into steam with a nuclear weapon, for the point of electricity generation. A later project, code-named PACER, investigated using H-bombs to heat liquid substances who could then have their heat extracted off and turned into power. A variation of the PACER idea became the germ for the development of inertial confinement fusion at Lawrence Livermore (i.e. try to shrink the secondary to a size where you don't need an atomic bomb to start fusion reactions, use a laser instead) in the early 1960s. The main arguments against a bomb-electricity scheme as far as I know are that the engineering would be pretty tough (especially when you factor in the radioactivity), the capital costs would be extraordinarily high, the fuel costs are extremely high (bombs aren't cheap), and the political fallout (hyuk yuk) would be immense. --Mr.98 (talk) 15:46, 19 June 2011 (UTC)

Such ideas were quashed as soon as the long-term effects of radioactivity on people became fully known. Thus, any nuclear reactions must be fully contained, as in a nuclear reactor, to prevent radiation from contaminating large areas.

You might also be interested in Project Orion, a proposal to use nuclear bombs for spacecraft propulsion. This would have the advantage of leaving all the radioactive debris in space. StuRat (talk) 16:01, 19 June 2011 (UTC)

I think they wanted to uses nuclears also for launching the ship, so there would have been a good deal of fallout on earth. And, if the ships are not constructed in space (or on the moon), how else would it be possible to get ships of the proposed size into orbit? 5BYv8cUJ (talk) 16:09, 19 June 2011 (UTC)

There are some variations of Orion that require nuclear detonations (a lot of them) for takeoff, and some which would use chemical rockets for takeoff (either as a whole or parts that would be later assembled). I recall seeing an animation someone had done once showing how one would take off with the bombs — it's a bunch of exponentially bigger and bigger bombs, a whole bunch of them. I can't find it right now, though. --Mr.98 (talk) 16:26, 19 June 2011 (UTC)

It is incorrect that "such ideas were quashed as soon as the long-term effects of radioactivity on people became fully known." They were fully known in the 1960s and 1970s, when the main investigations into these technologies took place. All of the designs proposed would have been made to fully contain the explosions underground, and the radioactive byproducts (e.g. radioactive water or flibe), which the US had a pretty good track record of doing by that point, with a few notable exceptions. There are a lot of things that stopped those programs, but new knowledge about the results of nuclear explosives was not one of them. --Mr.98 (talk) 16:26, 19 June 2011 (UTC)

Public attitudes in the US shifted away from nukes about the time of the Three Mile Island accident in 1979. Prior to that, most people believed the government's assurances that nukes were safe. Afterwards, it became politically impossible even to start a nuclear power plant in the US, much less do something as risky as detonating nuclear bombs to generate power. So, while scientists may have known about the risks of radioactivity earlier, the public didn't fully appreciate them, at that time. (The earlier images of people watching nuclear detonations, with sunglasses on, shows they weren't much concerned.) StuRat (talk) 18:51, 19 June 2011 (UTC)

I wonder if the Partial Test Ban Treaty was also a factor - although it excluded underground tests, according to the article it was initially negotiated with an eye toward it possibly being a Comprehensive Test Ban Treaty like what was adopted much later. Any project that relied on periodic underground nuclear detonations would have blown a hole, so to speak, in those negotiations. Wnt (talk) 19:53, 19 June 2011 (UTC)

StuRat, you're a bit wrong about your chronology. Public opinion turned away from atmospheric nuclear testing by 1963. That's why the PTB was pushed through, why Linus Pauling got the Nobel Peace Prize, etc. etc. etc.; TMI had nothing to do with that. What you see starting around 1981-82 is an increased fear of nuclear war (what some historians called "Cold War II", with Reagan and all that), but that's well after this sort of research had stopped. The types of photos you are talking about are 1. from the 1950s, and 2. only of people who are actually in the nuclear establishment (who have different opinions on nukes, generally, from that of the general public). Even by the 1950s the fallout issue was known publicly (the Castle Bravo incident publicized that for the first major time) and you start getting all of the "fallout is bad" push back (Godzilla, Them!, and many, many other mutated-monster movies, plus "fallout clouds killing everyone" lit and films); by the early 1960s you can find all sorts of discussions of fallout in really general interest periodicals like Readers' Digest and the like. The definitive book on this subject (which is an excellent book, by the way — a really quite fun read) is Spencer Weart's Nuclear Fear: A History of Images (Harvard University Press, 1988). Pretty good beach reading, if you ask me...

Wnt — the PTB played a role but not in quite the way you mean. It was because of the PTB that they started heavy investment in underground testing, which is exactly the kind of research that makes you able to do things like Project Gnome and PACER and other of these approaches. So I would see the PTB as actually a spur to this sort of research, and I don't think it's a coincidence that all of the projects on this front start around the same time the PTB was being debated. CTBT is much much later, but certainly it would affect any current work in this direction. The US gov't had no problem with underground testing, though, between 1963 and 1992, and tested literally hundreds of nuclear weapons during that time, some of which for "civilian" purposes. --Mr.98 (talk) 13:24, 20 June 2011 (UTC)

I remember there was once a discussion here on the ref desk about using a nuke to contain the Deepwater Horizon oil leak. AFAIK there had been some experiments of this kind carried out in Russia, but that idea never got off the ground. 67.169.177.176 (talk) 00:58, 20 June 2011 (UTC)

I hear that as well but immediately attributed that to media sensationalism. Who ever heard of stopping a leaking pipe by blowing up the end of the pipe that is leaking? Googlemeister (talk) 13:17, 20 June 2011 (UTC)

Red Adair, for one. 75.41.110.200 (talk) 16:36, 20 June 2011 (UTC)

Red used explosions to blow out the fires on a burning well, not to stop the leak. Fire wasn't really that much of an issue with the BP leak 5,000 ft underwater. Googlemeister (talk) 16:40, 20 June 2011 (UTC)

plant breathing at night and fresh morning air

If plants release CO2 at night then why morning air is called Oxygen rich and fresh air, it should be carbon dioxide rich.!!!! — Preceding unsigned comment added by 117.200.51.144 (talk) 14:47, 19 June 2011 (UTC)

I've never heard morning air called "oxygen rich". The CO2 and oxygen levels in the atmosphere don't vary all that much between day and night (there is a variation, but not enough to make any difference to anything). --Tango (talk) 15:18, 19 June 2011 (UTC)

Morning air is fresher because of the smaller amount of pollutants present, not because it has more oxygen. Dauto (talk) 15:43, 19 June 2011 (UTC)

And the reduced pollutants are due to factories and cars being used less at night, as well as dew removing particulates from the air. StuRat (talk) 18:54, 19 June 2011 (UTC)

This all sounds like nonsense. Can we have refs or links? μηδείς (talk) 02:25, 20 June 2011 (UTC)

What sounds like nonsense? Dauto (talk) 05:26, 20 June 2011 (UTC)

Agreed. I'm not going to provide links to prove the obvious, like that fewer cars are on the road overnight. If there's a specific item in question, then tell me. StuRat (talk) 16:25, 20 June 2011 (UTC)

A good deal of the "freshness" of the early morning air also has to do with the fact that a lot of harmful chemicals in the air are created by photochemical processes; for instance, tropospheric ozone is formed by myriad reactions that, for the most part, can only take place with the aid of the sun. -RunningOnBrains^(talk) 16:46, 20 June 2011 (UTC)

It might be a matter of perception. To me, if the morning air smells "fresher", it's just because it's cooler. That coolness might have some impact on the ability of smells to permeate. Warmer air often seems "smellier" than cooler air. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:25, 20 June 2011 (UTC)

With the help of Biotechnology study, How form (made) optimer?

Sir I take admission in Bsc Biotechnology. I want to cure cancer disease with the help of optimer. I little know about optimer , I think when we collide proton in optimer and proton get more energy. This energy damage carcinogenic cells which cause cancer because some types of cancer cause with the help of UV radition ,when we fall radiation on UV radition lot of energy produce and cancerious cell are damage, but one problem is create i don't know, how i produce rdiation ,how i form optimer, how i collide proton ? I am 12th class student , I think so but not any practice in this work. I know you help me and solve my problem.... — Preceding unsigned comment added by Chauhan jassi (talk • contribs) 15:14, 19 June 2011 (UTC)

If we knew how to cure cancer, we wouldn't be wasting our time on the Wikipedia Reference Desk! It's clear you don't enough about to subject to even get started on your idea, so I suggest you continue studying. After your BSc (and maybe a masters) you can apply for a PhD position and then you can do research into your idea. --Tango (talk) 15:23, 19 June 2011 (UTC)

(ec) I suggest reading Radiation therapy for a start. 5BYv8cUJ (talk) 15:24, 19 June 2011 (UTC)

And radiation therapy doesn't so much cure cancer as treat it. That is, certain types of cancers can be reduced, but only at the cost of damaging the surrounding tissue. A more promising "cure", IMHO, is to use genetic engineering to create viruses that can penetrate each cell, identify the cancerous ones by comparing their DNA with a template (taken from your cancer cells earlier), and destroy those which match. This might be a few decades away, but has the potential to be a 100% cure, as this could eliminate cancer cells anywhere in the body, regardless of the surrounding tissue, and including cancer that has metastasised. StuRat (talk) 18:59, 19 June 2011 (UTC)

Use the flu to cure cancer... interesting idea. BTW, I think this idea is actually at the clinical testing stage right now. 67.169.177.176 (talk) 01:05, 20 June 2011 (UTC)

Perhaps some early version of it is, but not the way I envisage it, with each virus quickly programmed to go after a particular section of cancer DNA (or RNA) marker extracted from the patient's cancer cells (during a biopsy). I can't see a "one size fits all" cancer cure, as there are many different varieties of cancer, and I wouldn't expect a single virus to be able to distinguish all cancers from all healthy cells, in all patents. Also, a "safety" needs to be built into the virus, so it can't replicate outside the lab, to prevent it from accidentally spreading. What kind of safety mechanism ? Perhaps it needs some raw ingredient to replicate which isn't found inside humans. Another advantage of this safety would be that you could control the rate at which the cancer is killed, by slowly administering the virus. For some large cancer masses, it might not be good to kill them all at once, as that could result in necrosis. StuRat (talk) 01:15, 20 June 2011 (UTC)

But your "virus" would have to be able to separate the DNA strings to compare them with a template. Probably it would be easier to hold the template against the RNA. 5BYv8cUJ (talk) 19:12, 19 June 2011 (UTC)

There is an "Optimer Pharmaceuticals" but its products sound like conventional drugs. I found mention of a computer program in a 1995 paper OptiMer but that isn't it either. I'm not aware of "optimer" as a biological term, though certainly it could have been a good coinage for something like an aptamer or other oligonucleotide used for treatment.

The original poster should note that DNA damage such as thymine dimers can cause cancer. Yet radiation therapy and many chemotherapy drugs such as cisplatin damage the DNA to (possibly) cure cancer. Thus, for a person without cancer to take anti-cancer drugs would usually increase his risk of cancer. The reason for this paradox is that cancer cells happen to develop mutations in such a way as to reproduce rapidly, leaving DNA constantly busy and vulnerable, without regard to the usual cellular safety mechanisms. Therefore, they are not ready to stop and wait when DNA damage is found, and can be driven to the point where damage becomes so severe that remaining safety features in place cause the cell to self-destruct.

I think the "protons" refer to proton therapy, a form of hadron therapy, a form of particle therapy, a form of radiation therapy. The chief benefit of this treatment appears to be to greatly increase the price. Wnt (talk) 20:12, 19 June 2011 (UTC)

June 20

Species of bird

What species of bird is in this picture? http://www.flickr.com/photos/dephisticate/5749045210/in/photostream Thank you--Hoangquan hientrang (talk) 01:06, 20 June 2011 (UTC)

It is definitely a cuculiform, most certainly a cuculid, although which species I know not. μηδείς (talk) 02:33, 20 June 2011 (UTC)

This suggests Guira guira. Ghmyrtle (talk) 12:34, 20 June 2011 (UTC)

Bug ID

This is it - sorry for the bad focus

I have found a number of green insects on the underside of the strawberry leaves in my garden in Washington, USA. Sorry for the really bad focus, but it's the best I could do. They are often found (as this one was) in the middle of some bubbly slime (ewwww). The eyes appear red or orange. Any help with the ID? Thanks - CT2011 (talk) 03:15, 20 June 2011 (UTC)

Leaf aphid, maybe? I googled [green bug strawberries]. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:19, 20 June 2011 (UTC)

Definitely not an aphid which has a much more cylindrical body and finer legs and aphids are not found in a 'bubble bath'. This looks very much like the larva of any one of many species of the so-called froghopper which forms a small pod of foam around itself for protection and is commonly referred to as cuckoo-spit, frog spit, snake spit, spittlebug and so on. Richard Avery (talk) 06:17, 20 June 2011 (UTC)

It kind of looks like a wingless cicada, but it's too small for that. Plasmic Physics (talk) 06:56, 20 June 2011 (UTC)

I'd agree with Richard - I think it's a froghopper. --TammyMoet (talk) 12:50, 20 June 2011 (UTC)

Thank you Richard Avery and TammyMoet for the informed answers - and I'm glad to hear the slime is just a bunch of sap. CT2011 (talk) 16:16, 20 June 2011 (UTC)

Lab management

Can anyone recommend some resources related to the organization / implementation of a microbiology project? Working in the lab, especially with multiple people on one bench, it has been difficult coordinating our experiments in a way that allows us to be thoroughly repeatable without being completely bogged down in documentation. Thanks, 68.231.149.156 (talk) 04:20, 20 June 2011 (UTC)

You're going to have to be a bit more specific about the problem you're hoping to solve. Do you have multiple people on one bench because of space constraints, or is it multiple people working on the same project on different shifts, or intermittently? Or multiple people using the same instruments, each for their own independent projects? Or what?

When you talk about coordinating the experiments to be thoroughly repeatable, do you mean that several people are each doing the same assay independently? Do different people perform different steps of an extended task? Are you generally performing the same assays over and over, or are there relatively few repeats of the same task before moving on to something else?

Are there issues with cross-contamination between assays or projects because of shared reagents, space, or equipment?

Ultimately, you can't avoid documentation if you want multiple people to do the same complex task over and over, reproducibly. Bite the bullet, write the SOP, and create a checklist to be used every time anyone runs through a given protocol. (Make sure there's a checkbox for each step, and a blank to fill in for each required measurement. Ten or fifteen minutes of paperwork feels like being "bogged down in documentation" until it saves you thousands of dollars in reagents and a week of repeating experiments trying to track down where a project went wrong.) TenOfAllTrades(talk) 14:19, 20 June 2011 (UTC)

Might I suggest a video camera ? You can record the experiment, and state the steps explicitly while performing them, rather than try to remember them and document them later. This should save time and effort. StuRat (talk) 16:20, 20 June 2011 (UTC)

Effects of bilateral seperation on humans.

From The Disasters of War by Goya. Do not attempt this experiment at home. Cuddlyable3 (talk) 15:32, 20 June 2011 (UTC)

If sufficient medical technology was present, what effects would it have on a human to be cute in half bilaterally? For this specific question I'd like to assume the medical technology can keep both seperate halves alive.

Ever since reading about folks who actually had the connective hemisphere nerves severed (with good cause obviously), I have been unable to let it go. So, let me see if i can sum up...We know that half a brain can (at times) still be utilized by a functioning human. What would happen if a bilateral split occured with the two hemispheres undamaged (but seperated by space,) and the person kept alive?

Specificly, would it display systems like sentience, consciousness, awareness, identity...etc. And how would one half interact with the other half? Would one person basically become two seperate people, or... Or I dont know what and Id really like to know. A quick summing up because of the confusing nature: Both seperated sides would need to be kept alive (by medical technology if necessary) and seperate from its 'twin' by space. The two are both alive, but can no longer interact as if they were a single being. Would they be emotionless? Develop seperate personalities? And what would happen to the personal identity of the seperated human, again assuming both sides could be kept alive and posessed one of the hemispheres of the brain. If clarification is needed further, feel free to ask. Its pretty confusing to try and write it all out. 74.128.56.194 (talk) 07:19, 20 June 2011 (UTC)

Do you want to just split the brain hemispheres apart or cut the entire body in half? I believe you meant just the brain, but please clarify. --Ouro (blah blah) 07:22, 20 June 2011 (UTC)

No, he means the entire body, as indicated in the lead sentence. You can't split the brain stem, that will cause some problems. Plasmic Physics (talk) 08:17, 20 June 2011 (UTC)

In that case, it doesn't matter what kind of medical technology is used -- the experiment will be invariably fatal for the subject. 67.169.177.176 (talk) 10:24, 20 June 2011 (UTC)

On the other hand, splitting the brain hemispheres apart is survivable, and can lead to some interesting psychological consequences. For further information, you might be interested in reading Stanislaus Lem's novel Peace on Earth (what the **** -- no article about this world-famous sci-fi author?!), which describes an astronaut who had received this kind of injury while on a space mission. 67.169.177.176 (talk) 10:30, 20 June 2011 (UTC)

He's under Stanisław Lem (also redirected from Stanislau Lem). AndrewWTaylor (talk) 10:33, 20 June 2011 (UTC)

Redirect created. Tevildo (talk) 17:03, 20 June 2011 (UTC)

I suspect what the OP is getting at is that if it were possible to create two separate, sentient humans from one, then the theory of the individual "soul" goes out the window. The closest thing to this I can think of is the Hensel Twins, except they have individual heads, so they are already two distinct entities. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:49, 20 June 2011 (UTC)

"I suspect what the OP is getting at is that if it were possible to create two separate, sentient humans from one, then the theory of the individual 'soul' goes out the window." That's right: and since identical twins don't share a soul (one can be evil, after all), despite having been a single person (fertilized egg, the religious definition of commencement of personhood), the concept of soul has been disproved. QED. --188.28.194.120 (talk) 20:44, 20 June 2011 (UTC) p.s. a christian mathematician could save the concept of a soul by laborious machinations: however, it would be at the expense of having any recourse against an early abortion, which would have to become as moral as the use of a condom.

Twins, especially identical twins, often have kind of a "psychic" connection (or "intuitive", of you prefer) and that's certainly true of the Hensel Twins; they do "share a soul" at least to some extent. However, they each have fully-developed brains, and distinct personalities and identities. Even forgetting splitting the entire body, does a complete split of the brain turn one person into two? ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:59, 20 June 2011 (UTC)

I think an interesting question is whether it is possible to make two people out of one—by any surgical procedure, "people" being defined much as it is defined now—having consciousness and a sense of self. Bus stop (talk) 11:19, 20 June 2011 (UTC)

Well a person only has 1 heart, and a half a heart will not do to keep a person alive. And how would they share 1 digestive system? Does person A get the stomach and person B get the small intestine? I suppose you could give each person a half length small intestine and that might work, but the stomach is not going to be dividable. Googlemeister (talk) 13:12, 20 June 2011 (UTC)

If a face transplant is possible then perhaps almost anything is possible. Dividing a stomach and reconstructing the material into two discrete stomachs may be possible. I find this as repugnant as anyone else, but it is just an interesting psychological question—can two people be made out of one? If so, their psychological histories would divide from the time they were separated. The main issue would focus on the brain, probably, as that is thought of as the seat of consciousness and a sense of self. Bus stop (talk) 13:55, 20 June 2011 (UTC)

This is an important exercise in philosophy, but I would recommend against jumping to conclusions. If a soul can be split, that doesn't mean it doesn't exist; it only argues against a few very rigid dogmas (and those holding them, if sufficiently dogged, can choose to ignore the odd conclusions drawn from them, without facing the possibility of scientific disproof).

Naturally the concept of atman, perhaps the most fundamental and important notion of the soul, is most consistent with a soul that is fungible, capable of being split and joined, existing in grey matter without specific individuality. But one can also consider the development of souls changing in a sort of spiritual development. Certain religions speak of Adam and Eve, created and split by God, living in a perfect paradise, from which all other people are made, sharing in the hopes and faults of their spirits; in a sense, then, all souls can be viewed as being split from a single predecessor. The idea remains mysterious, little affected by the progress of science; yet, with the approaching possibility of actually making and conducting many experiments with implications of this type, it will not be possible to simply ignore or idly guess at the issues. Wnt (talk) 23:03, 20 June 2011 (UTC)

We have an article on the Split brain syndrome, which is very interesting. There is certainly the interesting question to what extent we in general have two, not one, separate selves or consciousnesses, and in what ways these are and are not integrated into our usual everyday sense of a unified "self." WikiDao ☯ 18:38, 20 June 2011 (UTC)

Split brain shows that some stimuli and cognitive functions reside in different hemispheres of the brain from each other. Split brain syndrome is not split personality syndrome so I don't think SBS is enlightening for separate selves. Googlemeister (talk) 20:14, 20 June 2011 (UTC)

See also our Dual brain theory article, which, true, does not discuss the implications on sense of "self". That the two hemispheres can operate as two distinct "selves" when surgically separated suggests that they may also do so in some way when normally connected. Where is your sense of self located? One hemisphere alone seems sufficient to have a sense of self, and we have two: why don't we, or even split-brain patients, experience a dual sense of self? How do two separate but interconnected (half-)brains result in our usual everyday unified sense of self? WikiDao ☯ 21:34, 20 June 2011 (UTC)

Googlemeister: the OP has predetermined that the split halves be preserved on life support, indicating that any organs that were split, are replaced with machinery like a (cardiopulmonary bypass). Plasmic Physics (talk) 07:21, 21 June 2011 (UTC)

What about the catastrophic blood loss inherent in this operation? 67.169.177.176 (talk) 11:06, 21 June 2011 (UTC)

That and cardiopulminary bypass is not recommended for more then 6 hours though according to our article they are sometimes on it a few hours more then that. Also, it would be most inconvinient for a concious person as if either of your blood lines come out, you are going to bleed to death pretty quick if you don't reconnect. Googlemeister (talk) 13:20, 21 June 2011 (UTC)

Digital camera trouble

I've carried my Canon Digital IXUS 70 over 3 to 5 continents, including hikes through Kata Tjuta, up Angels Landing, a hot air balloon ride, cycle tours, and snowboarding in the Alps, usually storing it in an outer pocket for easy reach. After only a couple of years of this excellent treatment, it has developed a problem. Images show a darkish spot in the lower middle of the image. The spot seems to become more diffuse with wide angle focus, and more defined if zoomed in. See below. Does this seem familiar to anyone? Is there something that can be reasonably done to fix this? And is this a science, a computer, or a misc question?

Zoomed

Wide angle

Thanks! --Stephan Schulz (talk) 08:20, 20 June 2011 (UTC)

What you are seeing is dust on the lens elements, or on the sensor. Every time you move the lens in and out, air is drawn into the device, like bellows. I presume you have cleaned the front of the lens? If so, there is little that can be done other than trying to blow compressed air into the camera (which might damage it further). If you could disassemble the camera, you could clean the dust out, but on such a small camera, this is not really possible. I would suggest contacting a Canon service centre. If it was my camera, I would take compressed air and try to blow it through the gaps in the lens mechanisms. I can not suggest this to you though, as it could damage the camera. Zzubnik (talk) 09:07, 20 June 2011 (UTC)

I thought it was something like that. If it's the sensor, shouldn't it be invariant under zooming? There are some screws I might try to take it apart, and I certainly can get a can of compressed air. As it is, the camera is nearly unusable for my purposes, so I cannot lose much. Thanks! --Stephan Schulz (talk) 09:20, 20 June 2011 (UTC)

On reflection, you are 100% correct. It must be in the elements of the lens. I've taken a few cameras like this apart before, and as you can imagine, it's not always easy to get them back together! I did find the page listed below which shows disassembly of one of these cameras. Good luck, and please let me know how you get on :)

http://www.bomaus.net/index.php?option=com_content&view=article&id=54:canon-ixus-70-lens-error&catid=12:projects&Itemid=29

Zzubnik (talk) —Preceding undated comment added 09:44, 20 June 2011 (UTC).

It doesn't have to be on a lens element. There's probably a fixed low-pass filter, IR filter, or at least a clear protective layer of material between the lens assembly and the sensor itself. (It's relatively unlikely that there's actually anything right on the sensor chip proper; stuff that we'd say is on the sensor is actually going to be sitting on one of these layers just above.) If you have a little bit of schmutz on one of these protective/filter layers, you can still get the effect shown. At higher zoom factors and at smaller apertures, light rays striking the sensor will be coming in more parallel to one another than when you're shooting wide-angle shots or with wide-open aperture. So a little bit of crud just in front of the sensor will look darker and sharper under high-zoom, small-aperture conditions than it will at low-zoom, large-aperture.

That said, for your purposes it doesn't really matter precisely where in the optical train the crud is located; this isn't a dSLR where you can pop the lens off and (gently!) blow out the interior with air. As some of the other responses have noted, if you're comfortable with taking your camera apart (and running a very real risk of needing to buy a replacement, or seriously degrading the alignment and focus of your optics) then you can try disasssembling it to carefully blow out the dust from the accessible interior surfaces. Note that unless you do this very carefully under very clean conditions, you may end up just moving the dust around, or introducing new and interesting contaminants.

If you contact Canon, they should be able to point you to a service center that can do the cleaning; I'm not sure how the likely price will compare to a replacement camera. If you have a local, trustworthy camera shop you might consider arranging the service through them. While few, if any, shops are going to do anything besides box the camera up and send it to Canon on your behalf, the good ones will have seen the problem before and be able to give you some idea of how likely a successful fix is. TenOfAllTrades(talk) 13:42, 20 June 2011 (UTC)

Of course one of the biggest risks in taking the lens assembly apart is that you'll just get more dust in there. Even in places where there is not a lot of noticeable dust, the stuff gets everywhere. One trick I learned from applying screen protectors is, if possible, set up your work space in your bathroom and run the shower hot for a few minutes to get condensation in the air. Then wait for it to mostly dissipate before you take the camera apart, that should get rid of most of the dust. It's a good idea to take the towels and stuff out first and also don't wear wool or old clothes which might be dusty, synthetic or new cotton clothes tend to be less dusty. Vespine (talk) 01:24, 21 June 2011 (UTC)

Septic tank

how do i design a soak away pit/septic tank on a residential drive way; i need the structural details.remmy ogabi — Preceding unsigned comment added by Morbrasintegratedconcepts (talk • contribs) 11:07, 20 June 2011 (UTC) . I added the title to this question. Cuddlyable3 (talk) 11:20, 20 June 2011 (UTC)

To start with, a soakaway is completely different from a septic tank. Have you read the articles? Whatever it is you wish to build will be subject to varying local regulations so we cannot supply plans that will satisfy them all. Talk to your local water regulator or a builder.--Shantavira|^{feed me} 12:04, 20 June 2011 (UTC)

I'm going to assume that you need to dispose of water run-off from your driveway, not toilet waste. For that, perhaps you could dig a trench on either side, parallel to the edge of the driveway, and fill it with gravel. This will allow water to run down and fill the trenches, from which it can then slowly soak into the ground. The gravel is mainly to make it safe, so you don't fall into the trenches or get you car stuck in one, but also prevents the sides of the trench from collapsing. Note that you don't want these trenches close to your house, as then water might soak into the basement, or too close to the driveway, as then the driveway edges might be undermined and collapse. I'm not sure what the proper offsets are, however. StuRat (talk) 16:10, 20 June 2011 (UTC)

There are those grass paver things you can cover your driveway with- is that what you meant? You can find many of them online through Google. If this is homework for an engineering course, then you need to know the standard assumption for vehicle weight that a driveway has to be constructed for, you have to know which kind of plastic to use and what its strength is, and you have to work out how to design the modules so that they will meet the requirements for driveways. Itsmejudith (talk) 16:28, 20 June 2011 (UTC)

Laptop on the lap and heating

If I put my laptop on my lap, will that dissipate heat faster than on a table? (provider that table is colder than my lap and not considering the possibility of burning my skin). Quest09 (talk) 12:05, 20 June 2011 (UTC)

That depends on the relative thermal conductivities of your lap and the table, as well as on temperature differences. I'm always careful to position my laptop so that air vents are kept clear, and I rely on fan cooling, not conduction to my lap. It is possible to purchase cooling pads (powered from USB) to cool the underside of laptops, but I'm slightly suspicious of the logic in using extra power (and hence generating more heat) to try to reduce heating. You could use a pad of frozen peas from your freezer, taking care to avoid obstructing air vents, but it's not a solution I would particularly recommend. If you have an overheating problem then check that the cooling fan is working efficiently & not obstructed by dust etc. Dbfirs 12:43, 20 June 2011 (UTC)

These things look good for placing a laptop computer on. The "frozen peas" mention above made me think of this. Bus stop (talk) 13:09, 20 June 2011 (UTC)

If your lap top is over heating, it might be caused by excess dust in the fan which often can be cleaned with a Gas duster. Dauto (talk) 14:16, 20 June 2011 (UTC)

I'd be wary of putting a laptop on anything at near-freezing temperatures - you could cause condensation inside the case, and short something out. Instead, make sure the laptop is dust-free, and rely on air cooling. AndyTheGrump (talk) 14:34, 20 June 2011 (UTC)

Don't take me wrong. I think the pea bag idea is whacky too. But it wont cause any condensation inside the computer, rest assured. Dauto (talk) 16:45, 20 June 2011 (UTC)

Ironically, your lap is probably about the worst place for your laptop. People do not conduct heat very well, and are also too warm. A chunk of metal or glass underneath it on a table will conduct heat away much better. Alternatively, you might use an external fan, pointed at the hottest spots on the laptop, with it up on blocks to allow air flow underneath. StuRat (talk) 16:02, 20 June 2011 (UTC)

A lot of manufactures find lousy places to put the fan exhaust ports. A human lap can easily block them depending on the bagginess of the clothing and in some cases, how big the user's legs are. Sir William Matthew Flinders Petrie | Say Shalom! 16:04, 20 June 2011 (UTC)

Depending on certain details of the OP, there may be other side effects to consider. ;) Wnt (talk) 23:07, 20 June 2011 (UTC)

Truly dedicated computer geeks won't care. :) ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:32, 21 June 2011 (UTC)

In that they don't use them anyway ? StuRat (talk) 08:05, 21 June 2011 (UTC)

WLAN signal strength varies, distance the same

Why does the signal strength of my WLAN get stronger or weaker, even if I am not moving? (I suppose the router is not moving around). Quest09 (talk) 12:17, 20 June 2011 (UTC)

Many things could cause interference and thus signal loss: other computers, people between you and the router, etc. 88.8.78.155 (talk) 14:36, 20 June 2011 (UTC)

Also, the "algorithm" that actually shows you the signal strength is just an "estimate" which is calculated using various factors, like signal to noise ratio, which isn't just "absolute signal strength". So it's possible that the displayed strength you are shown changes without any appreciable variance in the actual absolute signal strength. Vespine (talk) 01:00, 21 June 2011 (UTC)

Why are some hair products for men only?

Some hair products are advertised as for men only. Just for Men (hair coloring product), minoxidil (for hair loss). They are applied topically. Why can't women use these products? — Preceding unsigned comment added by 173.49.19.207 (talk) 12:37, 20 June 2011 (UTC)

I suppose woman with a normal hormonal balance do not need minoxidil. The other cases might be just a marketing trick. The cosmetic industry is infamous for its bogus claims.Quest09 (talk) 12:49, 20 June 2011 (UTC)

"Just for Men" hair coloring is a marketing gimmick. It's not different in any appreciable way from comparable products for women; its manufacturer just wanted to be able to sell hair dye to men. Similarly, minoxidil is used to treat baldness in both men and women. You may be thinking of it as male-only product just because baldness is far common in men than in women. TenOfAllTrades(talk) 13:11, 20 June 2011 (UTC)

Products containing finasteride, which is teratogenic, should not be used by women of child-bearing age because of a strong risk of birth defects. — Preceding unsigned comment added by 148.177.1.210 (talk) 13:18, 20 June 2011 (UTC)

Finasteride + minoxidil are medicine (nothing to do with cosmetics). "Just for men" is a cosmetic product (nothing to do with medicine). I do not believe cosmetics could cause any harm (or even have a lasting effect) either in men or woman. You can put the label "Just for men" on everything that you want. 88.8.78.155 (talk) 13:24, 20 June 2011 (UTC)

You probably didn't mean to suggest this, but just for the record, cosmetics clearly can cause harm and can have lasting effects (lead-based Kohl, for example). If you have concerns about using these products, read the small print and check with a medical professional. 130.88.134.136 (talk) 14:25, 20 June 2011 (UTC)

Do they even use kohl anymore? I thought it was phased out a long time ago. 67.169.177.176 (talk) 21:10, 20 June 2011 (UTC)

OK, I reformulate: cosmetics are developed with the intention of not having any effect (thus not going thru any mandatory FDA expensive and long approval process). 88.8.78.155 (talk) 14:35, 20 June 2011 (UTC)

Men's hair needs tough strong stuff for all the tough things it gets up to in the day like playing football in the bar and getting that job, women's hair needs soft and gentle things to help it raise the children, have orgasms in waterfalls, and wander through meadows picking wild flowers. DuncanHill (talk) 14:28, 20 June 2011 (UTC)

Men's hair has to reflect the reality of surviving on foreign planets, while women's hair only has to reflect moonlight. Bus stop (talk) 15:25, 20 June 2011 (UTC)

While the same hair dye could work for both men and women, there are some differences which justify different product lines:

1) Women demand more color options.

2) Women have more tolerance for spending long periods of time with foul-smelling chemicals on their heads.

3) Men sometimes have facial hair which they would like to dye dark colors (if women have facial hair, they usually want to remove it or bleach it). A different technique is needed for dying facial hair, using a brush to apply it, instead of a squeeze bottle.

4) Women often have more hair, so need more dye per application.

So, it's not purely marketing, there are legit reasons to have two separate product lines. StuRat (talk) 15:42, 20 June 2011 (UTC)

i SWEAR BY gRECIAN pLUS fOAM. yOU JUST USE IT LIKE MOUSSE. lEAVES IN A LITTLE GREY, VERY SIMPLE, BUT NOT THE LOOK MOST WOMAN WANT. — Preceding unsigned comment added by 71.251.129.30 (talk) 20:49, 20 June 2011 (UTC)

Yes, but I've heard it causes damage to that part of the brain which controls the use of the CAPS LOCK key. StuRat (talk) 08:02, 21 June 2011 (UTC)

Well, Grecian Formula does contain heavy metals (Lead in the US, Bismuth in Canada and Europe). While probably safe "when used as directed" by men, I imagine they may have a harder time passing approval if it was marketed to reproductive-age women. - 174.31.219.218 (talk) 16:16, 21 June 2011 (UTC)

Lead#Health_effects says that lead poisoning generally occurs either by ingestion or by inhalation of lead dust, and that skin absorption of lead is negligible. So cosmetics that contain lead are not a health hazard when used as directed, either for men or for women. 67.169.177.176 (talk) 20:19, 21 June 2011 (UTC)

Blue whiting glowing in the dark

I have observed that Blue whiting's fishbones (and some flesh), glows in the dark. Why is it like that? Does that happen with many fish?88.8.78.155 (talk) 13:06, 20 June 2011 (UTC)

This sounds like a type of bioluminescence. Normally, bioluminescence i sa type of chemiluminescence, that it it is caused by a chemical reaction, normally between a pair of enzymes which when they interact, produce the light. In a long dead (and presumably cooked) fish, such enzymes are likely deactivated, and what you describe (glowing in the dark) sounds more like a type of fluorescence or phosphorescence, though the distinction between the two is largely quantum mechanical in nature, phosphorescence generally persists a lot longer, so it is usually the source of something "glowing in the dark". As for what the phosphorescente substance is in blue whiting, I'm not sure, but hopefully those links will give you some background reading on related phenomena. --Jayron32 14:20, 20 June 2011 (UTC)

The fishbones were not cooked. In the mean time, I think maybe it was not the fish, but some bacteria in the fish which were glowing. I'll check the next time I buy fish - of this or other type. 88.8.78.155 (talk) 14:26, 20 June 2011 (UTC)

Bones do contain phosphorus, so perhaps some form of that is causing the phosphorescence. StuRat (talk) 15:52, 20 June 2011 (UTC)

To clarify, bones contain calcium phosphate, not elemental phosphorus. 67.169.177.176 (talk) 21:12, 20 June 2011 (UTC)

Strange Fish

Opsanus tau, probably not the fish in question

What is this strange fish caught in a crab trap in the Hudson River? https://picasaweb.google.com/100877348058812847095/Piermont#5620005527927467298 Sesquepedalia 14:39, 20 June 2011 (UTC) — Preceding unsigned comment added by Sesquepedalia (talk • contribs)

Why in God's name are you fishing in the Hudson? That question asked, I am not sure what it is, and I'm a pretty avid fisher. Sir William Matthew Flinders Petrie | Say Shalom! 15:38, 20 June 2011 (UTC)

Some kind of monkfish? Wrong shape for a flounder which do live there. 75.41.110.200 (talk) 16:26, 20 June 2011 (UTC)

The caption says oyster cracker which is another name for the Oyster toadfish but our pictures of that fish look much uglier. 75.41.110.200 (talk) 16:29, 20 June 2011 (UTC)

Actually, the caption says "oyster crusher", not "cracker", and the fish is not Opsanus tau (pictured) which I think looks prettier, not uglier, but is probably in the same toadfish family.μηδείς (talk) 20:44, 20 June 2011 (UTC)

Sorry, oyster cracker/oyster crusher were listed as alternate names on another website. Oyster crusher is also the name of an unrelated animal, the Port Jackson Shark. 75.41.110.200 (talk) 21:23, 20 June 2011 (UTC)

typhoons in Russia

All typhoon tracks from 1980-2005; none hit Kamchatka.

How frequently do typhoons hit the Kamchatka peninsula? Googlemeister (talk) 16:39, 20 June 2011 (UTC)

Very rarely. A few have gotten close in the past 30 years, but as you can see in the image at right, even those were quite weak. It seems like it may have been hit in 1954 and 1955, but there is very little information available (not surprising from before the end of the Cold War).-RunningOnBrains^(talk) 17:03, 20 June 2011 (UTC)

Ooh! A Jackson Pollock! {The poster formerly known as 87.81.230.195} 90.201.110.44 (talk) 17:59, 20 June 2011 (UTC)

Typhoons "feed" off of warm water. Without it, they loose their energy and fade away (which is why they never go far inland). The Kamchatka peninsula isn't exactly known for warm, tropical water, so typhoons have to use the energy they have already gathered up to get that far north, which usually isn't sufficient unless you have a really warm summer and a really large typhoon. --T H F S W (T · C · E) 19:23, 20 June 2011 (UTC)

I understand that, but then Nova Scotia isn't known for that either and it gets hit by a hurricane every now and again. Googlemeister (talk) 20:04, 20 June 2011 (UTC)

It should be noted that the diagram above does show a few storms tracking over Russia, if not Kamchatka specifically. Several seem to track over, or close to, Primorsky Krai and at least 3-4 appear to make a direct hit on Vladivostok. --Jayron32 19:53, 20 June 2011 (UTC)

And I think Nova Scotia is closer to tropical regions than the Kamchatka peninsula. --T H F S W (T · C · E) 23:41, 20 June 2011 (UTC)

It's clearly not impossible; as I said, from maps it appears that it was hit twice in the 50s. Hurricane Faith in the Atlantic was a hurricane as far as 62 degrees north, and the southern end of Kamchatka is only 51 North. It's not a common event, but it can happen.-RunningOnBrains^(talk) 00:29, 21 June 2011 (UTC)

Reynolds number for different constrictions

Constriction at the end of a tube

Hello, I'm interested in calculating the Reynolds number for constrictions of different sizes and shapes but all similar to that in the diagram to the side. Since I don't have any background in physics, I'm having a difficult time understanding the equations in the WP article. I'm basically after an equation in which I can plug in variables for different constrictions. The constrictions are either hollow circular, elliptical, or rectangular prisms. The fluid is air, which has a kinematic viscosity of about 0.15 cm²/s according to one of my sources. As I've certainly given too little information about this to completely solve my problem, perhaps you could ask me what else you need to know to make feasible a general equation for different constrictions. I really appreciate the help.--el Aprel (^facta-_facienda) 21:15, 20 June 2011 (UTC)

The flow before and after the constriction will have different Reynolds numbers given by the first equation in the article you linked. Dauto (talk) 02:00, 21 June 2011 (UTC)

Dormancy breaking

Is there any article that lists seeds and required kinds of dormancy breaking? I only found Seed dormancy and Wikipedia:NOTHOWTO. 5BYv8cUJ (talk) 21:28, 20 June 2011 (UTC)

Scarification and the other terms given at Seed#Inducing_germination may be useful search terms to find this information on the internet. E.g. http://www.google.co.uk/#&q=scarification+seeds 2.97.210.205 (talk) 11:58, 21 June 2011 (UTC)

Thank you for your help. 5BYv8cUJ (talk) 18:17, 21 June 2011 (UTC)

I've found Scarification (botany) but it dosnt tell you much. 92.29.113.106 (talk) 23:05, 21 June 2011 (UTC)

I take it then that the answer to my original question is "NO" and "BECAUSE". No, there is no article that lists different kind of seeds together with their required kind of dormancy breaking, because (people here are afraid that) this could violate Wikipedia:NOTHOWTO. 5BYv8cUJ (talk) 18:17, 21 June 2011 (UTC)

It might also be because, assuming it wouldn't be wikiheresy, no one who has the necessary knowledge and interest has yet been moved to compile the data and write an article. {The poster formerly known as 87.81.230.195} 90.201.110.203 (talk) 18:52, 21 June 2011 (UTC)

And even more so if doing that would result in the work being censored removed because of pre-emptive fear for wikeipedian wrongdoing. 5BYv8cUJ (talk) 19:18, 21 June 2011 (UTC)

June 21

Is there an estimate available for the fraction of the Earth's mass that is dark matter?

Also, what about the fraction of stars made of dark matter? If a hefty fraction, wouldn't it greatly change the way stars work? Thanks, Rich Peterson24.7.28.186 (talk) 05:17, 21 June 2011 (UTC)

Although the total mass of dark matter is estimated to be nearly five times as much as the mass of normal matter in the universe, most of it is thought to exist outside planets and stars. I suppose it is a matter of opinion whether the billions of neutrinos passing through the earth make up part of the earth's mass, but I think it would be a very small proportion. Perhaps an expert can make a calculation? Dbfirs 06:21, 21 June 2011 (UTC)

That's right. The fraction of mass composed of dark matter is negligible. Dauto (talk) 06:51, 21 June 2011 (UTC)

Rarer than the total amount of ununoctium present in the whole earth? Plasmic Physics (talk) 06:59, 21 June 2011 (UTC)

Not that rare. But read dark star for an interesting speculative possibility that dark matter played an important role on the behavior of the very first stars of the universe. The OP's instinct that dark matter might change the way stars work is correct for these stars (If they turn out to actually exist). Dark matter plays little role on the behavior of regular stars like the sun. Dauto (talk) 07:06, 21 June 2011 (UTC)

Also read dark matter#Indirect detection experiments where the possibility of measuring dark matter trapped within the earth or the sun is briefly mentioned. Dauto (talk) 07:16, 21 June 2011 (UTC)

I was under the impression that the phrase "dark matter" is simply a term used as a catch-all label for "that which we cannot observe/identify/explain" much like "terra incognita" was used on old maps. Roger (talk) 07:19, 21 June 2011 (UTC)

Whilst the term was invented for this "missing mass" we didn't know anything about, since significant research has been done it's more like a known unknown. 'Dark' is a useful word because it implies we can't observe it, or at least technology-wise, it is difficult to directly observe. There are other 'dark' things theorised, Dark energy, Dark fluid and Dark flow for example. Since we have little idea of what dark matter actually is, then it may well have more than one constituent part, so 'dark matter' can be consider a grouping of sorts, but it seems to be a useful and well defined one. Grandiose (me, talk, contribs) 07:25, 21 June 2011 (UTC)

Here I get a density of 0.3–0.39 GeV/cm³. Multiplied by the volume of the Earth that's 2–3 kg, or 3–4 million kg in the volume of the Sun. In either case, that's about one part per septillion. It would be a bit odd to include that mass in the "composition" of the Earth/Sun, because the dark matter is a gas of rapidly moving, barely-interacting particles (like neutrinos, which are one component of it), and there just happens to be that much of it passing through the Earth/Sun at any given time. -- BenRG (talk) 08:19, 21 June 2011 (UTC)

The content of the link reads "Error 404 - Not Found". Do you need a login there?

BenRG probably meant this [14] - it looks like he hand-typed the URL and missed out the 'r' in 'dark'. CS Miller (talk) 12:58, 21 June 2011 (UTC)

Thank you. 5BYv8cUJ (talk) 14:06, 21 June 2011 (UTC)

I copied and pasted it. I have no idea how that happened. (Now fixed.) -- BenRG (talk) 20:36, 21 June 2011 (UTC)

Dark matter is subject to gravitation, so one would expect it to aggregate inside stars and planets. With this, it should be possible to calculate some limits on its temperature (the stuff (to avoid the word "particle") would have to be faster than the escape velocity, and with some nifty observations it should be possible to calculate a lower limit for the interaction probability dart to normal matter and dark to dark matter, too, but I havn't seen anything yet. 5BYv8cUJ (talk) 11:52, 21 June 2011 (UTC)

Unlike ordinary matter, dark matter cannot cool (radiatively), therefore it is not expected to aggregate, at least not to anything like the density contrast represented by stars and planets. Dark matter is distributed like a tenuous gas with very little, if any, self-interaction. --Wrongfilter (talk) 14:14, 21 June 2011 (UTC)

I'm not thinking of density but of gravitation. The article linked states a speed of 300km/s, this is far less than the escape velocity of the sun, so the dark matter would be trapped in the gravity well. With ever so small interactions it would start to aggregate. Might well be the aggregation is too small to detect, but from the principle I don't see what's wrong with that. 5BYv8cUJ (talk) 14:52, 21 June 2011 (UTC)

Yes, that sort of calculation is routinely done. Just as an example, read the abstract of that paper. Dauto (talk) 14:58, 21 June 2011 (UTC)

Thank you. And I see that as long as the results are negative they won't appear in the headlines, and so people like me wouldn't notice this sort of research at all. 5BYv8cUJ (talk) 15:31, 21 June 2011 (UTC)

Any average particle speed like 300km/s is given at infinity, where the escape velocity is zero. The particles will speed up as they approach a gravitating object and slow down as they leave, always exceeding the local escape velocity. Some kind of dissipative interaction (i.e., friction) is always necessary for capture. Frictional effects on dark matter are small but nonzero, so some capture is expected, but not a lot. -- BenRG (talk) 20:36, 21 June 2011 (UTC)

I see your point. A particle moving at 300km/s (not really matter what direction) would be accelerated towards a gravity well and thus gain more speed to overcome the escape velocity. Are there any mathematical models that account for that? 5BYv8cUJ (talk) 20:54, 21 June 2011 (UTC)

As Dauto points out, this is a standard problem (could be a homework problem for astrophysics students). The DM particles have some scattering cross-section for interactions with nuclei, so you can calculate the capute rate by the Earth. For the typical DM masses that one considers, these then settle in the Earth's core. They then get into thermal equilibrium with the Earth's core, which then allows you to compute the self-annihilation rate. This then yields a differential equation for the total DM content of the Earth (capture minus self annihilation is the increase per unit time). On the very long term you would then get a dynamical equilibrium between self-annihilation and capture. However, in case of the Earth that would take hunderds of billions of years (for the typical cross-sections that are assumed for DM).

The Sun captures so much more DM than the Earth, that the self annihilation signal from the Sun (in the form of neutrinos) is expected to be larger than from the Earth. Count Iblis (talk) 15:40, 21 June 2011 (UTC)

Primary 5 Science

What will be the coloured water level in the tube that is inserted into a enclosed tank topped soda lime which a mouse is in it? And explain why? — Preceding unsigned comment added by 220.255.1.83 (talk) 07:46, 21 June 2011 (UTC)

Please do your own homework.

Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know.

Also, you're obviously missing some numbers. You can't get numbers out of a calculation without first putting some numbers in. StuRat (talk) 07:58, 21 June 2011 (UTC)

Sounds like this old riddle: "If a car is driving west at 50 miles per hour, what time is it in Chicago?" ←Baseball Bugs ^{What's up, Doc?} carrots→ 08:44, 21 June 2011 (UTC)

Are you about 10 years old? (That's about right for Primary 5 in the Scottish education system), but this seems far harder than questions for 10 year-olds. Anyway, the mouse will breathe in oxygen and exhale (breathe out) carbon dioxide. The carbon dioxide is then absorbed by the soda water, reducing the volume of air. Assuming the coloured water is part of a manometer then the liquid will move towards the tank. You will need to know

1. The mouse's rate of oxygen consumption
2. How long the experiment is running for

From this you can calculate how much oxygen the mouse has used. Divide this by the volume of air in the tank to determine the percentage of air used, and thus the pressure drop in the tank. Assuming the other end of the the manometer is sealed, then it is simple to work out how much the coloured water will move.

If you don't know how much oxygen the mouse uses, then it can be calculated if you know its basal metabolic rate, and assume that its burning glucose.

If you get stuck, tell us how far you've got and we can help you further. CS Miller (talk) 11:51, 21 June 2011 (UTC)

Atmospheric content of nitric oxide

Does anybody know where I can find an exhaustive list of Earth's atmospheric content? Specifically I have had some trouble finding information of the average content of nitric oxide aka nitrogen monoxide aka NO. Does anybody know the value or where to find it?

cheers. Denito (talk) 08:57, 21 June 2011 (UTC)

You may be interested to look at [15] and [16] only released in the last week. Also Atmosphere of Earth gives some information. But not NO. nitric oxide is oxidised in air to nitrogen dioxide which is listed. Graeme Bartlett (talk) 11:13, 21 June 2011 (UTC)

metastasis

6cm adenocarcinoma in bile duct, grown for almost 5.5 years. What is the probability that the cancer cells have metastasized? — Preceding unsigned comment added by 199.224.149.10 (talk) 10:13, 21 June 2011 (UTC)

If that's a request for medical advice, we're not allowed to answer it. If it's a homework question... we're not supposed to answer it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 10:31, 21 June 2011 (UTC)

Any 2011 news on the 2000 year-old Judean date palm?

I havnt been able to find any 2011 news, only blog posts that refer to information of years earlier. Is there any 2011 news yet? Has it flowered, or is it male? 2.97.210.205 (talk) 12:20, 21 June 2011 (UTC)

Our article which you linked to includes information from 2010 which is not years earlier. A quick search easily finds [17] with comments from 2010 suggesting the sex is undetermined. It also suggests your best bet may be to just contact the person involved. I was suprised that they didn't just try to determine the sex genetically but from [18] and [19] it seems the Sex-determination system in date palms is only beginning to be understood. If you do contact the person involved you may want to consider suggesting they get in touch with the team studying the sex determination system in date palms as it would seem both would be interested in each other's work but it's possible they may not be aware of each other. Nil Einne (talk) 14:56, 21 June 2011 (UTC)

"Our article which you linked to includes information from 2010 which is not years earlier". Who said it wasnt? You first link links to something dated 2009. 2.101.2.152 (talk) 17:21, 21 June 2011 (UTC)

How does a dry "dead" seed come to life?

I assume that the seed is not metabolising at all, yet somehow it awakens. Animal cells never do this. 2.97.210.205 (talk) 12:22, 21 June 2011 (UTC)

There is an article on germination. And animals can do similar things, see Tardigrade. 5BYv8cUJ (talk) 12:30, 21 June 2011 (UTC)

I don't know the answer, but some animals do this too. Look at http://en.wikipedia.org/wiki/Cryptobiosis and http://en.wikipedia.org/wiki/Anhydrosis Zzubnik (talk) 12:33, 21 June 2011 (UTC)

Seeds can be alive or dead. A seed's probability of being able to germinate diminishes with time, but it depends on how it's kept. Cold storage will keep individual seeds alive longer. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:52, 21 June 2011 (UTC)

I can think of two different concepts of "alive or dead". One is that alive means having an active metabolism, the second is having the potential for having an active metabolism (when water is present, for example). 5BYv8cUJ (talk) 20:45, 21 June 2011 (UTC)

A live seed can sprout under the right conditions. A dead seed cannot sprout under any conditions. That's the difference. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:12, 21 June 2011 (UTC)

I'm wondering how on a molecular level a dessicated cell can restart its 'machinery'. 92.29.113.106 (talk) 23:09, 21 June 2011 (UTC)

comets

Have any retrograde orbit comets been observed? As in a comet which goes around the sun in the opposite direction that earth does within roughly 30deg of inclination of earth's orbit? I would like to clarify that I am speaking only in terms of periodic comets. Googlemeister (talk) 14:57, 21 June 2011 (UTC)

Quite a few. Halley's Comet is on a retrograde orbit, for instance. Its inclination is 162.3°, so I guess that conforms to your constraint (180° would be exactly retrograde). See also Retrograde motion. --Wrongfilter (talk) 15:41, 21 June 2011 (UTC)

So what causes the retrograde orbits of comets when all planets and moons in the solar system, as well as the vast majority of asteroids have a standard orbit that I assume is caused by the formation of these objects from the sun? Is the material from comets not from this system? Googlemeister (talk) 19:15, 21 June 2011 (UTC)

Possibly, though quite likely complex gravitational interactions working on a comet over many millions of years, coupled with an already eccentric orbit, could alter such an orbit to do strange things. These things are literally unpredictable given the number of gravitational interactions that a comet has to contend with during its lifetime. (not just hard to calculate, but literally impossible, see n-body problem). --Jayron32 20:23, 21 June 2011 (UTC)

You might be interested in the articles Scattered disk and Oort cloud for the origins of many long-period comets. 67.169.177.176 (talk) 20:26, 21 June 2011 (UTC)

And also the article Centaur (minor planet). 67.169.177.176 (talk) 20:27, 21 June 2011 (UTC)

spin altering

http://www.sciencedaily.com/releases/2011/06/110605132431.htm 'because photons at the right frequency make the antiatom's spin flip up or down.' why do photons at the right frequency make the antiatom's spin flip up or down? — Preceding unsigned comment added by 82.38.96.241 (talk) 20:37, 21 June 2011 (UTC)

Photons, when treated as a particle, are carriers of spin. You can read about spin and how it participates in atomic interactions. When a photon and an atom "interact", there is often a transfer of energy, momentum, and spin. One such interaction causes a change of the atom's spin (or, changes the spin of one or more electrons around the atom). In simple quantum interactions, the spin can only take one of two possible values; this is usually notated "up" and "down." In more complicated quantum mechanical systems, the spin can take on other values. Nimur (talk) 21:22, 21 June 2011 (UTC)

Bugonia, bee mimics

I am currently doing research for the bugonia article. One of the sources has a theory that the so-called bees were actually flies that looked remarkably similar to bees, possibly Eristalis tenax. It seems the author did not know the technical term for Batesian mimicry. So I was wondering where I could find a more comprehensive list of species meeting these critera:

• looks like a bee
• lays it's eggs in carrion
• widespread in the ancient Mediterranean region
• has a maturation time of approximately 10 days, or
• has a maturation time of approximately 30 days, or
• has a maturation time of approximately 10 days on a 20 day old corpse

Thanks! Craig Pemberton (talk) 21:33, 21 June 2011 (UTC)

I am not aware of any species that meets your criteria that is not a hoverfly. Many species of hoverfly are common in their ranges. However, even the ancients may have noticed that bees have four wings, whereas all dipterans have two. If you have access, you can probably find some good articles by searching for 'syrphidae' in a biological review journal, such as entomological review. There may be a few bee-looking hymenopteran saprotrophs, but I can't readily find any indication of such. SemanticMantis (talk) 22:27, 21 June 2011 (UTC)

Habitable planet/moon pair.

I know this has been asked here before, but I want to add some things to it.

Would it be possible for both elements of a planet/moon system (probably more like a double-planet system in this case) to be capable of supporting human life? When this question was asked before, I think the asker (for lack of a better term) intended for both bodies to be more or less Earth like, but let's say the worlds were each on opposite extremes of the habitability spectrum. So the primary body would be a large terrestrial planet but still capable of supporting human life comfortably, while the smaller object would be a barely habitable Mars-sized planet with a thicker atmosphere. Probably the only way such a system could exist is through capture, or maybe through co-accretion, but then again, I'm no expert.

I guess my question then is: can a two-planet system consisting of two (relatively) large "Earthlike" planets exist naturally?

EDIT: added signature. 70.246.235.69 (talk) 21:42, 21 June 2011 (UTC)

Foil pan heat conductivity of a disposable grill

How good can the foil pan of a disposable grill conduct heat? Would it work better if it were better of worse heat conductor? Wikiweek (talk) 22:15, 21 June 2011 (UTC)

Irish hurricanes

Is it even possible for a hurricane to hit Ireland I know we get tail ends but is it possible for full blown tropical hurricanes to hit Ireland. The reason I ask this because of the warm current of the gulf stream should enough to keep a hurricane going. --109.78.92.74 (talk) 23:00, 21 June 2011 (UTC)

None has ever done so. The nearest is Hurricane Debbie (1961), which was downgraded to a tropical storm before it hit Ireland. European windstorm lists other major storms. We can only speculate about what weather might result from the changing climate. -- Finlay McWalter ☻ Talk 23:10, 21 June 2011 (UTC)

Why can I see clearly when I wear two pairs of glasses?

Why can I see clearly when I wear two pairs of my own prescription glasses, one on top of the other? Shouldn't the outer pair distort the correction produced by the inner pair? I think that if a person with perfect vision wore my glasses, his own vision would be blurred. So if one pair corrects my vision, shouldn't the second pair blur it? --82.31.133.165 (talk) 23:32, 21 June 2011 (UTC)