Wikipedia:Reference desk/Archives/Science/2010 May 24

= May 24 =

OIL SPILLS
Technically aren't asphalt highways just oil spills mixed with dirt? 71.100.3.228 (talk) 02:26, 24 May 2010 (UTC)
 * No. Part of the definition of "spill" is that it is accidental. Also, asphalt is a specific component of crude oil, rather than crude oil itself. --Tango (talk) 02:32, 24 May 2010 (UTC)


 * That's right &mdash; fractional distillation is used to separate crude oil into things like gasoline, kerosene, and asphalt. But then the asphalt is indeed mixed with dirt; our asphalt article, in its Rolled asphalt concrete section, states that an asphalt highway is actually only 5% asphalt itself, and 95% "aggregates", meaning gravel, sand, and stones.  Comet Tuttle (talk) 06:56, 24 May 2010 (UTC)


 * Roads and urbanization are a different form of habitat destruction than oil spills. They definitely all  involve introduction of non-natural (or at least, non-local) materials into the environment, often significantly altering the local ecosystem.  However, unlike oil spills, roads have a measurable benefit - improving the quality of life for humans - so there is at least some level of tradeoff to consider.  Nimur (talk) 14:43, 24 May 2010 (UTC)


 * Asphalt is not a liquid, so it doesn't have the same effects that the liquid crude oil has on birds, fish, etc. --Chemicalinterest (talk) 14:55, 24 May 2010 (UTC)
 * Roads are also confined to discrete areas; their destruction is intense, but it covers only a fraction of land area. Roads generally do not move on their own, so animals have some hope of avoiding their hazard. Oil spills on water can spread widely and uncontrollably. Sea birds and other animals have trouble avoiding oil slicks. However, note that motor vehicles can drip appreciable amounts of engine oil onto road surfaces, which tends to run off during rain storms, thereby polluting the runoff. A busy roadway thus functions like a low-level oil spill that continues indefinitely. A widespread shift to battery electric vehicles and bicycles instead of the current dominance of internal combustion engine vehicles would greatly reduce oil pollution on road surfaces. --Teratornis (talk) 19:40, 24 May 2010 (UTC)
 * Well, if you're advocating some kind of worldwide mandate to ban automobiles and force everyone to use bicycles or glorified golf carts, then we will veto it in the United Nations before you can say "oil spill". This kind of change is absolutely out of the question for civilized, industrialized nations -- what about the eighteen-wheeler trucks that take merchandise from the warehouse to the local neighborhood store?  A much better way would be to implement more frequent, more stringent and consistent mechanical inspection requirements for motor vehicles to make sure they don't drip motor oil all over the place -- this would achieve substantially the same result, but without nationwide economic upheaval that your proposal would cause. 67.170.215.166 (talk) 06:38, 25 May 2010 (UTC)
 * There are electric cars available today that are not remotely similar to golf carts &mdash; they have highway performance that matches up quite nicely with gasoline-powered cars. Range is a bit of a problem &mdash; the Chevy Volt has a nice interim solution, with a gasoline engine that doesn't kick in until it's needed, which except on long trips, it usually won't be.
 * The big problem with them, at the moment, is price. Hopefully that will come down.
 * But of course if/when that happens, if they're going to be our transportation solution for large numbers of people, then we're going to need a lot more generating capacity. I suspect the only realistic way of getting that much capacity, without producing lots of greenhouse gases, is to build a lot of nuclear plants.  Unfortunately it takes upwards of a decade to get a nuclear plant on-line.  That's why I think we need to get some in the pipeline starting now.  --Trovatore (talk) 22:01, 25 May 2010 (UTC)
 * Excellent idea, why don't we write Congress and demand more nuclear reactors? 67.170.215.166 (talk) 01:41, 26 May 2010 (UTC)

acetone
does acetone evaporate like alcohol or does it leave a residue? can u use it on food surfaces? —Preceding unsigned comment added by Tom12350 (talk • contribs) 03:37, 24 May 2010 (UTC)
 * Yes, it evaporates very quickly, maybe not as quickly as most alcohols though. No, I would never use it on anything that would ever contact food. Beach drifter (talk) 03:44, 24 May 2010 (UTC)
 * After a little reading, it appears to be hardly toxic at all. I still see no reason you would need to use it in the kitchen. Beach drifter (talk) 03:47, 24 May 2010 (UTC)

can i use it on a plastic counter top, and a particle board kitchen table with a wood looking plastic/ vinyl vanear  —Preceding unsigned comment added by Tom12350 (talk • contribs) 04:11, 24 May 2010 (UTC)


 * It's a solvent, so plastic-based and printed food surfaces might get damaged, or colors from packaging transfer. What would you intend to use it for? FT2 (Talk 04:12, 24 May 2010 (UTC)
 * There are lots of products specifically designed for this use, visit your local supermarket. Vespine (talk) 04:50, 24 May 2010 (UTC)


 * No. Don't use it on those - it will dissolve them, then evaporate, leaving an impossible to clean mess. Not really a mess - more like a mushy smear of the veneer. It's pretty non-toxic though (it's actually legal as a food additive!), and does not leave any residue behind, so in that regard it's safe in the kitchen. I use acetone to remove stickers. But you have to work VERY fast, it evaporates very quickly - even the open bottle will evaporate. Put the acetone on a tissue, and rub the sticker - don't put the acetone on the sticker, it will dissolve the glue, then run, leaving a bigger sticky spot than when you started. Ideally have a second person to cap the bottle in between putting some on the tissue. Acetone is probably the fastest evaporating solvent commonly available. Ariel. (talk) 05:32, 24 May 2010 (UTC)
 * A little WD-40 will remove stickers as well and there's no bottle to close. Dismas |(talk) 08:10, 24 May 2010 (UTC)
 * You dont' want to use that stuff in the kitchen, though, it leaves a mess and it can be toxic if ingested. 67.170.215.166 (talk) 06:43, 25 May 2010 (UTC)
 * How much are you using?! Do you lick your counter clean?!  I doubt any reasonable person would A) use so much WD-40 as to be a health hazard and B) just let WD-40 sit on their counter after cleaning off sticker residue and then use that spot to make a sandwich.  Dismas |(talk) 08:06, 25 May 2010 (UTC)
 * I'd rather not use any petroleum distillates in my kitchen, unless absolutely necessary. 67.170.215.166 (talk) 01:57, 26 May 2010 (UTC)

how will plastic-based and printed food surfaces get damage if they use it in labs to clean plastic labware? will it help if i dilute it 50-50 w/water? —Preceding unsigned comment added by Tom12350 (talk • contribs) 06:13, 24 May 2010 (UTC)


 * Not every plastic is the same, some will be totally unaffected, others will dissolve into goo - there are a LOT of different kinds of plastic. I don't know what water will do, probably it will slow down the dissolving. Ariel. (talk) 08:08, 24 May 2010 (UTC)

arent there only 7 kinds of plastic? —Preceding unsigned comment added by Tom12350 (talk • contribs) 08:41, 24 May 2010 (UTC)
 * Category:Plastics. 212.219.39.146 (talk) 08:47, 24 May 2010 (UTC)
 * There are many more! I used acetone in the lab and I saw somebody cleaning a keyboard. The Grey keys like Strg And Alt got very soft and the printed letters vanished, the other white keys showed no problem and ended up very clean.--Stone (talk) 09:37, 24 May 2010 (UTC)
 * While there are seven classifications in the Resin identification code, the seventh is "other", and would include everything from ABS to nylon to teflon to polycarbonate. -- 174.24.200.38 (talk) 04:38, 25 May 2010 (UTC)

The better cleaning agent for you might be, what other people use for disinfection, it is a mixture of 70% isopropanol and water.--Stone (talk) 09:37, 24 May 2010 (UTC)

i already tried that. will it help if i dilute acetone 50-50 w/water? —Preceding unsigned comment added by Tom12350 (talk • contribs) 10:49, 24 May 2010 (UTC)


 * That would slow its evaporation, but it would also slow its cleaning abilities, so there would be no net difference. You can put it in a spray bottle, not a mist one, a squirt one. --Chemicalinterest (talk) 11:02, 24 May 2010 (UTC)

i dont understand. if i dilute it wont it be less corrosive? —Preceding unsigned comment added by Tom12350 (talk • contribs) 11:14, 24 May 2010 (UTC)
 * Yes diluting it will make it less likely to damage the plastic. Alchohol is a better choice though if you have it. What are you cleaning?87.102.85.123 (talk) 11:47, 24 May 2010 (UTC)


 * I used to be a follower of the "throwing assorted chemical compounds on a surface makes it cleaner" school of thought, I must admit, but a lot of 'em will ruin your crap if you aren't careful. The way I see it, just because something kills bacteria and viruses doesn't mean it's safe for you to eat. It's not that antiseptics and antibac soap are actually making the surface cleaner on a microscopic scale - they're simply poisons designed to kill microbes instead of humans. Which is why you're supposed to wipe away the disinfectant before you eat off something you use it on. In the same vein, just because something is caustic doesn't mean it's necessarily going to clean whatever you put it on. And if its effects are 75% "creating a goopy catastrophe" and 25% "cleaning the surface", no matter how much you dilute it you're still going to get three times as much goop as cleaning action. ZigSaw 11:46, 24 May 2010 (UTC)
 * I don't understand why you are so intent on using acetone in your kitchen. Did you get a hold of an industrial quantity and just trying to use it on EVERYTHING? Lol… if you absolutely insist on using it, at least try rub some on the least conspicuous spot first and leave it for a few minutes and rub it again, see if it damages the surface before making a mess of it.. My know it all uncle once used to clean his fancy hi fi with metho, one day he decided that acetone might be a better idea and it melted the face of the LCD display making a matted mess you couldn't even see through, he was gutted. Vespine (talk) 23:13, 24 May 2010 (UTC)

Crystal Violet
Hi there :) My name is Elin and I'm from Sweden. Right now I'm writing an assay about terraforming in astrobiology with chemistry and biology as "main subjects". I'm now stuck on gram staining and I really need to know how crystal violet is produced. When I read this article: http://en.wikipedia.org/wiki/Crystal_violet, I don't quite get the production. Mostly it's because I don't understand everything that is written, for example I don't get if it's ment that it is redox (gain) or oxidation (loss) that happens when you oxidize the compund in the second prodction step. And what about the last step? Is that the final step to get crystal violet, or is it a step to produce something else since it says "Hydrolysis of crystal violet gives the carbinol"? And what is a leuco? I've written about the first two steps, but I've left out what I've asked about (the oxidize-question, leuco and the third step). I feel like I should bring more to the table in order to get a higher grade and it would be sad if difficulties with language should stop me from getting the grade that I need. Please try and explain clearly and detailed. I don't mean that I want it to be simple, just that i'm thankful if you explain a lot since I don't understand all english words. Thanks a lot! /Elin —Preceding unsigned comment added by Ailithey (talk • contribs) 08:56, 24 May 2010 (UTC)


 * The leuco (white or colourless) form is oxidized with oxygen. The carbinol is a alcohol derived from methanol by substituting the hydrogen by something different, here the central C-OH is attached to three 4-dimethylaminopheny substituents.--Stone (talk) 09:46, 24 May 2010 (UTC)


 * The German article Kristallviolett has a better image what happens.--Stone (talk) 09:49, 24 May 2010 (UTC)


 * Gentian violet and Crystal_violet are the same substance, but the Gentian violet is about the medical use!--Stone (talk) 09:53, 24 May 2010 (UTC)

Thanks a lot, I'm starting to get it. But if you look at the article http://en.wikipedia.org/wiki/Crystal_violet, I still don't really get the production. The ast step says this: A typical oxidizing agent is manganese dioxide. Hydrolysis of crystal violet gives the carbinol: [C(C6H4N(CH3)2)3]Cl + H2O → HOC(C6H4N(CH3)2)3 + HCl Is this step part of the production of crystal violet? Do you get crystal violet by following all three steps, or is the last step the formula for the production of a carbinol? —Preceding unsigned comment added by Ailithey (talk • contribs) 10:38, 24 May 2010 (UTC)
 * The article was a bit confusing - I've changed it to avoid confusion - http://en.wikipedia.org/w/index.php?title=Crystal_violet&oldid=363908374
 * It should be clear now. The last step was not part of production. 87.102.85.123 (talk) 12:06, 24 May 2010 (UTC)

center of mass
why does objects rotate around it's centre of mass ..? I mean as a example, when we throw a rod (something like that) in the air holding at the edge,we can see it rotates around its CM.dany (talk) 13:19, 24 May 2010 (UTC)


 * Try to imagine an object that does not rotate around its CoM. Then that would mean that the CoM of the object would rotate around some point (inside or outside of the body). Therefore the CoM would be accelerating toward the point of rotation (centripetal acceleration). That would require an external force. Count Iblis (talk) 14:06, 24 May 2010 (UTC)


 * When an object is forced to rotate around something other than its center of mass by an external force, the object will precess, and if it continues to rotate for a long enough time (e.g., low friction or low damping), it will eventually change its rotation through a precession so that the rotation aligns with its principle axes. Nimur (talk) 14:48, 24 May 2010 (UTC)


 * You mean principal axes. lets mantain the principle of spelling words correctly. Dauto (talk) 16:18, 24 May 2010 (UTC)
 * Let's punctuate our contractions correctly, and capitalize the first word in each sentence. --Teratornis (talk) 19:25, 24 May 2010 (UTC)
 * lets not. Dauto (talk) 02:27, 25 May 2010 (UTC)


 * Let's envision your example of the thrown rod. The center of mass will follow a parabolic path  back to Earth, and in that respect the rod will act as if all its mass is located at the center of mass. In addition, the rod can have rotation around one or several axes, but the center of mass will still follow the same parabola.  If it didn't, it would act like a thrown marble rippling up and down instead of following a parabola back toward earth.  That would require energy instead of just gravity.Overjive (talk) 03:16, 26 May 2010 (UTC)  —Preceding unsigned comment added by Overjive (talk • contribs)

aching muscles = laughing reflex?
Yesterday I played in an action cricket tournament. Being the most unfit person ever, today my muscles are all exacting their revenge on me and I could hardly roll myself out of bed this morning. Funny thing is, I discovered that whenever I move (and stretch some of my sore muscles) I get this urge to laugh for no apparent reason. Even thinking about it now makes me giggle. Is this a known thing or am I the only one? Could it be related to tickling (I'm VERY ticklish and laugh uncontrollably when people try to tickle me, even before they've made any contact)? I tried Googling but I'm getting false hits about laughing so much your muscles ache. Zunaid 16:28, 24 May 2010 (UTC)
 * The Delayed onset muscle soreness article does not mention this effect. You could ask on that article's talk page if you get no help here. --Teratornis (talk) 19:30, 24 May 2010 (UTC)
 * You evidently have an easily-triggered laugh reflex, so perhaps the pain in your muscles triggers this by reminding you of the fact that you find the situation amusing.   D b f i r s   06:57, 25 May 2010 (UTC)

Sodium hypochlorite and Sodium acetate
I mixed solutions of sodium hypochlorite and sodium acetate together. Is the hypochlorite strong enough to oxidize the acetate ion? I noticed some gas being produced (not much), but otherwise there was no indication of a reaction. Thanks. --Chemicalinterest (talk) 17:19, 24 May 2010 (UTC)
 * (edit conflict with below) Oxidize it to what? Peracetic acid?  Usually that's done with hydrogen peroxide, but hypochlorite isn't that much weaker of an oxidizing agent than peroxide, so I suppose it could.  Even with hydrogen peroxide, the equilibrium still lies to the left, so it makes sense that only a little, if any acetic acid would be oxidized. Buddy431 (talk) 20:40, 24 May 2010 (UTC)


 * Did you look on a standard reduction potential table? We've linked them before, and there are many of them out there on the internet and in books as well; the numbers should tell you if it is possible for hypochlorite to oxidize acetate.  The only possible products are the chloride ion and carbon dioxide, so if hypochlorite DID oxidize acetate, you'd get some bubbles.  -- Jayron  32  20:31, 24 May 2010 (UTC)
 * The standard reduction table here doesn't have acetic acid, so no beans. And why do you say only that Chloride and CO2 are the only products?  It could only be reduced to chloride gas (a weaker oxidizing agent than the hypochlorite), which could be the bubbles observed. Buddy431 (talk) 20:42, 24 May 2010 (UTC)
 * Chloride gas doesn't exist, but hydrogen chloride might. --Chemicalinterest (talk) 21:06, 24 May 2010 (UTC)
 * I meant chlorine gas. Hydrogen chloride would stay in solution. Buddy431 (talk) 22:35, 24 May 2010 (UTC)


 * Doubtful. Chlorine gas disproportionates to hypochlorite and chloride in any basic solution, see Chlorine_bleach.  Cl2 may be an isolatable intermediate, but I think that spontaneously, the chloride ion ends up being the lowest-energy product here.  Consider that the Eo for the reduction of chlorine gas is highly positive itself... -- Jayron  32  21:03, 24 May 2010 (UTC)
 * It's not clear what the reaction would be here:
 * Acetate oxidise to CO2 - can't find potentials either - note - acetic acid is quite resistant to oxidation - it's used as a solvent in many oxidation reaction.
 * Peroxide - maybe?
 * Reaction to form a chloroacetate - this seems quite likely - chlorite would be reduced in this reaction - so I suppose acetate must be oxidised. I'm fairly certain this reaction will go, don't know how fast.
 * There are simple tests to see if a reaction has happened - such as add chlorite to excess acetate, let it react, then add iodide - if chlorite remains iodine will be produced (visible), as a control compare with the control reaction (chlorite + water . no acetate) 77.86.125.207 (talk) 18:33, 25 May 2010 (UTC)

Special Relativity
One of the implications of Einstein's Theory of relativity is- If two observers are in relative motion, they will not, in general, agree as to whether two events are simultaneous. If one observer finds them to be, the other, in general, will not. Now I read this example in Halliday/Resnick, Fundamentals of Physics. Two observers Sally and Sam stand in two long spaceships. They are stationed a the midpoint of the two ships. The relative velocity of ssSally with respect to ssSam is v separating along a common x axis. They are stuck by two meteorites just when they were crossing each other, one setting off a red flare and the other blue, leaving marks at R and B on ssSam and R' and B' on ssSally. Let us suppose that Sam and Sally are positioned right in the middle of R and B and R' and B'. Sam receives the two light waves at the same time and gave the following explanation. Sam: Light from event red and light from event blue reached me at the same time. From the marks on my spaceship, I find that i was standing halfway between the two sources. Therefore, event red and event blue were simultaneous events. Sally and the expanding wavefront from event red are moving towards each other, while she and the expanding wavefront from event blue are moving in the same direction. Thus, light from event red reaches her before light from event blue. Her explanation goes as follows. Sally: Light from event red reached me before light from event blue did. From the marks on my spaceship, I find that i too was standing halfway between the two sources. Therefore, the events were not simultaneous. These reports do not agree. Nevertheless, both observers are correct.

My question goes as follows: If we observe the two spaceships from a third inertial reference frame, we will discover that the two events occurred simultaneously as they occurred at a unique instant when the two spaceships coincided on the x-axis. Does that mean Sally's explanation was wrong? If that is so, is the first postulate of the Theory of Special Relativity contradicted? Please explain the validity of Sally's explanation in this light. --Lightfreak (talk) 18:20, 24 May 2010 (UTC)


 * You said that Sam is equidistant from R and B and saw light from the two flares at the same time. That means that the two collisions were simultaneous in the rest frame of Sam, so your third inertial frame is the same as the rest frame of Sam. There is no unique instant when the spaceships cross because they have length; it takes a while for them to pass each other completely. There is a unique instant in a unique inertial frame when the ships occupy the same range of x coordinates, but the collisions didn't happen at that instant. (One of them may have, but not both.)


 * I don't think there's much insight to be gained into special relativity by looking at different reference frames. It's like checking that 5+5+5 = 3+3+3+3+3 and 7+7+7+7 = 4+4+4+4+4+4+4 and so on. What you really want to understand is why multiplication is commutative in the first place; then you don't have to try all the special cases. The best way to understand this problem is to draw a spacetime diagram showing all of the events. -- BenRG (talk) 18:51, 24 May 2010 (UTC)

What is the point of a lawn?
Besides the aesthetic aspect, is there any coherent reason to constantly trim, weed, fertilise and reseed the part of your property with nothing built on it? I can understand preventing erosion, but wouldn't regular old wild weeds do that? Does anything horrible happen when grass gets too long? It seems to me that a ludicrous amount of money goes into herbicides, mowers/gas, fertilizers and all kinds of ugly side effects of fighting natural selection to get a "good-looking lawn". Unless there's some benefit I'm not seeing... ZigSaw 20:36, 24 May 2010 (UTC)


 * Small animals, some of which may be pests, can hide in tall grass. Jc3s5h (talk) 20:41, 24 May 2010 (UTC)


 * I figured lawns were a sign of the wealthy being able to afford land and to manicure it as well. As well as for aesthetic purposes, lawns provided ample grounds for one's "constitution" I suppose. More recently, lawns are smaller and part of the package when you buy a nice house. It's probably more for aesthetic purposes now than it ever was, because most lawns (at least around where I live) are so small, you can't even play Badminton on them. Backyards usually allow for a single sport and maybe that's it... barbecues and other activities are restrained to a porch. I know that with my family's country estate, we have no "lawn", because it's all overgrown and wild and absolutely beautiful. (According to lawn, it's still a lawn.) Of course, lawns at, like, Versailles, are simply ostentatious but stunning. –  Ker αun oςc op ia◁ galaxies  20:43, 24 May 2010 (UTC)


 * There's nothing wrong with doing things for aesthetic purposes. You either do something because you want to adhere to cultural norms, or you do it specifically to fuck with cultural norms.  So, either you maintain a lawn because its expected, and your culture tells you it looks good, or you let it grow wild because you want to intentionally go against those norms.  Either position is equally valid, and both have as much weight.  It comes down to personal aesthetic choice and little else.  -- Jayron  32  20:52, 24 May 2010 (UTC)


 * Kids and pets can play on them. They are pleasant places to sit or snooze with a beer and a good book.  Grass is basically outdoor carpeting.  If you don't have grass then you have...what?
 * Nothing - you live in an apartment with no outdoor space.
 * Dirt - which you can't lie on and isn't comfortable to walk on - and is unusable for days after rain.
 * Xeriscape - less work but also uncomfortable to lie on. Also, doesn't naturally absorb dog poop and is hopeless for little kids to kick a ball around on.
 * Concrete - ugly, also not very useful for all the reasons above.
 * If you want extra space beyond your indoor living space, a garden...and therefore a "carpeted" garden is the way to go. Grass is the natural choice because unlike most other plants it's evolved to survive being grazed by herbivores - and can therefore be mowed to keep its height in check and to maintain the density needed.
 * Having said all that - my house is situated out in woodland and my kid is old enough not to need to go out and play in it - so we mostly have wild grass which doesn't grow too long because of the dense trees - and doesn't get mowed because we don't live someplace where we have to conform to social norms with manicured grass.
 * SteveBaker (talk) 21:05, 24 May 2010 (UTC)


 * This probably goes back to the rise of surburban life - in the 20th century - before then people didn't have lawns - they either lived in towns (with almost certainly no garden at all) or in the countryside.. Lawns did exist prior to surburbanisation - notably common land such as the village green; the lawns would be 'mowed' mostly by sheep - which do a very good job.
 * The rise of surburban life meant that everyone got their own miniature village green - called a garden. (along with a miniature mock tudor mansion - or 'semi').
 * That is basically the origin of the grass lawn. Basically people now imitate the cutting sheep once did using lawnmowers. Strange behaviour but true. If you don't believe me ask on the humanities desk. Obviously grass is good for playing on. Doh, I just found out all this is at lawn, nobody will read it anyway. 87.102.85.123 (talk) 21:39, 24 May 2010 (UTC)
 * We do have a History of the lawn article: they appear to date from before the 20th century: the first lawnmower (as opposed to a scythe) was invented in 1827. Buddy431 (talk) 22:28, 24 May 2010 (UTC)

As mentioned above by many, having a lawn at the backyard is actually quite nice. I just want to point out that you don't really need to use herbicides, fertilisers or gas to have a nice lawn. I don't use any of that and still am quite happy with my lawn. Dauto (talk) 03:19, 25 May 2010 (UTC)
 * Some lawns have just the right amount of moisture from ground water and sun to only require mowing. Other lawns require watering and mowing. Other lawns require so many things that its better to zero-scape. If you use mulch to zero-scape then it will retain moisture and and allow the zero-scape plantings to thrive. The problem is when neighbors want to dictate whether you have grass or zeroscaping and constantly yap to the police. You should have the right to have any kind of "lawn" your heart desires that is affordable and not a hazard to others. Some people though claim that zeroscaping hampers firefighters and attracts venomous or disease carrying creatures. If the economy gets any worse though even fancy dancy bank lawns might be used to grow tomatoes. 71.100.8.229 (talk) 20:52, 25 May 2010 (UTC)
 * (That's xeriscaping, not zero-scaping, by the way.) —Bkell (talk) 17:24, 26 May 2010 (UTC)

It's because lush, green grassland would have been a sign of plenty to our very distant ancestors. Food, water, and good visibility to protect against preditors. Even our eyes are structured to process horizontal objects more readily than vertical. It's a comfort factor that is bolstered by other social and cultural points raised above. 24.130.145.253 (talk) 04:33, 26 May 2010 (UTC)


 * I recommend this from The New Yorker: Turf War: Americans can’t live without their lawns—but how long can they live with them? (by Elizabeth Kolbert). Mathew5000 (talk) 09:40, 16 July 2011 (UTC)

Old Testament
Old Testament states "Adam has lived 930 years".How this can be explained? Real today's years, or possible short years of the old time? Does the length of years,as days,may be variable? Today 1 year=365 days, but billion years ago 1 year=15 days for example?TASDELEN (talk) 21:13, 24 May 2010 (UTC)


 * There's no evidence such intervals have changed that much in Earth's history. 67.243.7.245 (talk) 21:32, 24 May 2010 (UTC)


 * In scientific terms, it is explained by pointing out that many cultures have myths that are not scientifically accurate. Anything other than that is sheer interpretation. Creationists and others who are decidedly not scientific (in that they take their conclusions as givens and then work backwards from there) usually say things like "God let him live that long" and "since the time of the Flood people have been more and more sickly and sinful and degraded" and things of that nature. See e.g. Answers in Genesis, a young-earth creationist ministry. But there is absolutely zero scientific evidence for this and it is entirely implausible from a truly scientific standpoint. AIG happily distorts scientific evidence to fit its very literal interpretation of the Bible. Frankly I think (as a nonreligious person) that such analytical attempts miss out on the entire point of the Bible, which was not meant to be considered a science textbook. But that's a personal opinion, to be sure. --Mr.98 (talk) 21:34, 24 May 2010 (UTC)


 * (edit conflict with above x2) Look at this article we have: Longevity myths. Some scholars argue that people inflate the lifespans of their important patriarchs and elders (sociological/anthropological reasons I guess, I'm not in this field, so I can't discuss that aspect any more). Note that most (i.e. all) non-religious scholars do not believe that there was a literal single first human (named Adam or otherwise). Buddy431 (talk) 21:37, 24 May 2010 (UTC)


 * (ECx3) I don't know why this is on the science desk since the obvious scientific answer is it's all nonsense, but AFAIK it's generally held by those who believe in those parts of the bible literally that human age was significantly reduced after the great flood. E.g.     . The reason for this is obviously something those who do believe in such things can't agree on, since it isn't really discussed in the bible but it's either thought of as a result of direct action by god (punishment or whatever), the problems/consequences that resulted from flood or the way humans have lived since then (see the earlier links some of which include discussion). Not to do with changes in the length of years AFAIK. Nil Einne (talk) 21:38, 24 May 2010 (UTC)


 * Not sure where you got a billion years from, neither creationists nor evolutionists would try to argue that anything like first humans were around a billion years ago. For some actual science, a DAY is determined by how fast the Earth spins on its own axis, a YEAR is determined by how long the Earth takes to orbit the sun. Days and years are independent of each other, a planet can have a long day and a short year, or a long year and a short day, there is no correlation. For example, in the Moon's orbit around the Earth, Moon days and years are actually equal, they are both one Earth month. We're less interested in length of days for the time being. As for years, the orbital period of any object around a much more massive object, like the Earth around the Sun is directly determined by the distance between the objects. This means: how far the Earth is from the Sun. The further apart the objects are the longer the orbital year. Mercury is only 0.4 of the distance from the Sun to the Earth and it has a year of about 88 days, Venus is 0.7 of the distance from the sun to the earth, it has a year of 224 days. Earth obviously takes 365 days to orbit the sun, Mars is 1.5 the distance from the Sun to the Earth and it has a year of 780 days. So for the earth to have a shorter year it would have to be closer to the Sun. There's no evidence that the Earth shuffled around or changed places since the formation of the solar system, there may have been some catastrophic events which changed the year a bit, but there's some decent evidence that the Earth has been at least in the Habitable zone, since life arose anyway. Vespine (talk) 22:42, 24 May 2010 (UTC)


 * So just for completeness, for Earth's year to be 15 days, it would have to be 0.15AU away from the Sun, that's a third of the distance to Mercury which is already a hot Sun scorched rock with any hope of an atmosphere blasted away long ago, quite certainly incapable of harbouring any life. So we can be pretty certain that at no stage during evolution of life was the Earth's year as short as 15 days. Going by the habitable zone link I gave above, I think shortest possible year that the Earth with life could have is about 345 days. Vespine (talk) 23:01, 24 May 2010 (UTC)


 * The explanation that I am familiar with is the confusion between the lunar month and the solar year that has occurred before the stories of the Bereyschitt (Book of Genesis) were written down. I think this is the explanation Zenon Kosidowski gave in his "Biblical stories" (Russ. transl. from Polish: Библейские сказания) book. Kosidowski is almost certainly not the first one to come up with it, though; I do not know who is. Our Longevity myths article mentions this explanation, too. --Dr Dima (talk) 22:46, 24 May 2010 (UTC)


 * So that means he lived 930 months which would be 77.5 years, that's much more believable, while still being very old for the time. Vespine (talk) 23:04, 24 May 2010 (UTC)


 * According to http://multilingualbible.com/genesis/5-9.htm, Enos (or Enosh) fathered a son at the age of 90 years. According to http://multilingualbible.com/genesis/5-12.htm, Kenan fathered a son at the age of 70 years.  If a "year" was a month, then 90 "years" meant 7 years and 6 months, and 70 "years" meant 5 years and 10 months. -- Wavelength (talk) 23:22, 24 May 2010 (UTC)


 * We may have ended up with some ages in months and others in years. Hunter/gatherers tend to use months, while farmers tend to use years, with herders using a bit of each.  Since society of the time had a mixture of farmers and herders, they may have gone back and forth between the two systems.  And just as we often omit the word "years" when giving our age, so do those who give their ages in months.  Also realize that many books of the Bible were told, retold, written, rewritten, compiled together from multiple accounts, etc., to make the final text.  This method results in rather poor quality control and many inconsistencies.  This was also common to other books from antiquity, such as the Odyssey and Iliad.StuRat (talk) 00:27, 25 May 2010 (UTC)


 * So Enos fathered a son at 90 years old even though he died about 15 years before? (905 months = 75.4166667 years) I never knew the bible discussed sperm preservation and artificial insemination (well not counting the virgin Mary). And to think some Christians are opposed to these sort of things despite having the clear approval of god! Nil Einne (talk) 08:39, 25 May 2010 (UTC)


 * There were also likely many mistakes in the Bible, such as confusing two people with the same name, or maybe people just lying about their ages. But a large portion of the ages seems to be around 12 times what would normally be expected, so confusion over months and years is the most likely explanation for most of this. StuRat (talk) 02:37, 26 May 2010 (UTC)


 * Five months equaled 150 days, according to http://multilingualbible.com/genesis/7-11.htm, http://multilingualbible.com/genesis/7-24.htm, http://multilingualbible.com/genesis/8-3.htm, and http://multilingualbible.com/genesis/8-4.htm. -- Wavelength (talk) 23:46, 24 May 2010 (UTC)


 * The modern practice of observing nature, making written records, and thinking freely and critically are recent developments. Galileo Galilei is considered to be the father of this scientific approach to thinking, and he did not do his ground-breaking work until the early 1600s.  Prior to Galileo’s new approach to thinking, myth, superstition and intuition were all that was available.  People were illiterate and favourite stories were passed by word-of-mouth from parents to children, generation after generation, gathering embellishment along the way.  The ancient scriptures, including the Bible, were written by men in that era of myth, superstition and intuition.  We should not be surprised when we find things in these ancient scriptures that are not believable.   These things should be ignored.  Dolphin  ( t ) 23:50, 24 May 2010 (UTC)


 * That is not true. Schliemann found Troy based on the Iliad record. Archaeological sites in modern Israel, Palestinian Autonomy, and Jordan are too numerous to even start to mention, and match very well the Biblical record, at least in their location (see e.g. Temple Mount, Tel Megiddo, Tel Hazor, Tel Be'er Sheva). Timelines are far more fuzzy, as expected for the events that took place several hundred years before being written down. Regarding month / year confusion, I recall Kosidowski speaking specifically about people's ages; it may have something to do with how the human age used to be specified 3000-4000 years ago. The day and the month of the Great Flood are indeed specified, as Wavelength has mentioned; but that does not mean that Noah's age is accurately recorded. --Dr Dima (talk) 00:08, 25 May 2010 (UTC)


 * I didn't imply that everything found in ancient scriptures is incorrect or unsound. My view is that when we find things in these ancient scriptures that are not believable, we should not believe them.  See Scientific scepticism.  The alternative, to which User:TASDELEN alludes, is that the things in the ancient scriptures must be correct and therefore we need to construct an explanation that makes them believable.  Dolphin  ( t ) 04:38, 25 May 2010 (UTC)

As someone who believes in the literal truth of the Bible, I'm rather confused by the idea that "most non-religious scholars do not believe that there was a literal single first human" — wouldn't standard evolutionary theory hold that there was a point at which one organism reached the point that it would be classified as Homo sapiens? Nyttend (talk) 05:44, 25 May 2010 (UTC)


 * Not really, we have a Most recent common ancestor also Mitochondrial Eve and Y-chromosomal Adam. I don't think you could really pinpoint the origin or Homo Sapiens to one individual. Even if we are commonly descended through ONE of the individuals, there were thousands of other very similar individuals in the same species which just happen not have surviving descendants today. Vespine (talk) 05:55, 25 May 2010 (UTC)


 * Not really. Speciation is a much more fuzzy and fluid concept. We don't really have a hard-and-fast definition of what makes one group of living things a distinct species. Some of the stuff is really obvious (for example, dogs are different than cats), but at the edges it becomes quite fuzzy. For every aspect of the standard "textbook" definition of distinct species, there are exceptions which are common enough to make the definition problematic. There is the Mitochondrial Eve, often cited as the ancestor of all modern humans, but that doesn't make her a single individual which was a unique species different from the other members of her community. After all, she had to be able to mate with the members of her community to have viable offspring; which would make her the same species as those other members. At a temporally zoomed-out view, we can say that the first modern humans developed sometime around, say 200,000 years ago. But its not like on Monday there were no humans, and on Tuesday there suddenly was one. AT any given point, there are a population of fully interbreedable individuals; that is usually the common definition of a species; when two populations drift genetically apart to the point where they are no longer able to produce viable offspring with each other, we generally hold that they are now different species. But its not a binary state; if we go back to the time when the populations became seperated, they likely would be considered the same species for many thousands of years before genetic drift causes them to differentiate. There isn't a single individual which represents the new species. -- Jayron  32  05:57, 25 May 2010 (UTC)
 * Postscript: Found a good link for Nyttend which discusses in more detail what I was trying to explain above. See Species problem.  -- Jayron  32  06:10, 25 May 2010 (UTC)
 * See also ring species (and linear species), where there are a number of different communities of a species, each community is slightly genetically different. Each one can breed with its neighbours, but not with the neighbour's neighbour's. If the community in the middle were to be wiped out, then there would be two unique species, albeit very similar to each other. CS Miller (talk) 11:50, 25 May 2010 (UTC)

Vespine says: "I think shortest possible year that the Earth with life could have is about 345 days". Then, if the velocity of the light has a fixed value, the definition of light-year distance should be changed to be "light-day" or 1000 LD distance, as " Days and years are independent of each other, a planet can have a long day and a short year, or a long year and a short day, there is no correlation...".I understand 1 Earth's day length is innate,is constant while 1 Earth's year length is variable. So, the distance of the Earth to the Sun is variable.GOD has not placed the planets at a fixed distance and let them orbit the Sun at these fixed distances, on a fixed elliptical orbit as said Kepler in 1609.TASDELEN (talk) 10:30, 25 May 2010 (UTC)
 * Nice and reasonable comments!
 * Sorry I'm struggling to understand what you mean by all of that.. Barring any cataclysmic events, these days both the year and the day of the Earth are quite stable. See Stability of the solar system. I was referring to the period during the formation of the Earth or when there might have been other cataclysmic events, not in the recent or even not so recent past. Vespine (talk) 11:43, 25 May 2010 (UTC)


 * I meant the non Stability of the solar system; because,as you say,"I think shortest possible year that the Earth with life could have is about 345 days".So, 1 year may be=to 345 days, in an older time. Then ligth-year distance, at that old time should be = actual measurement*345/365; which is impossible.This why "the non-stability" should be considered. TASDELEN (talk) 14:04, 25 May 2010 (UTC)


 * No, TASDELEN, you seem to have have misunderstood some of the earlier discussions. Neither the Earth's day length nor its year length are "innately fixed" so you can't define one variable as a constant and then compare another independent variable to it. The only constant is the second, because we have (now) defined it according to another fixed value based on the invariable properties of light and independent of anything to do with the Earth's motions. We extend the defined second to a defined year by simple multiplication, and the light-year is based on that, not on any derivitive of the actually variable day length and/or year length.
 * The length of the day (defined as noon to noon) varies slightly through the year due to the eccentricity of the Earth's orbit around the sun: its average over the year depends (mostly) on the speed of the Earth's rotation on its axis. This has been gradually slowing since the formation of the Moon around 4.5 billion years ago, due to tidal acceleration (which both slows the Earth's rotation and moves the Moon further away), so as one tracks further back in time the days were shorter and there were more of them in the year, and also the months were slightly shorter (because the Moon was closer and orbited the Earth faster): "620 million years ago: the day was 21.9±0.4 hours, and there were 13.1±0.1 synodic months/year and 400±7 solar days/year", as that last linked article says. However, these changes are very long term, and the day and month lengths a mere few thousand years ago when the accounts preserved in the bible were formulated would not be noticeably different from today's.
 * The Earth's orbit, and consequently the length of the Earth's year also varies slightly over very long periods due to several factors, but not by any amount significant for everyday purposes (like measuring lifespans) over historical periods; nonetheless we no longer ultimately define any scientific measurements relative to the actual year, but instead to a year derived from the independently defined second. Vespine was alluding to a purely theoretical situation where the Earth would have fewer days (of the current length) in the year by virtue of orbiting closer to the Sun in accordance with Kepler's third law; increased insolation due to the simple inverse-square law would clearly place a lower limit on the proximity, and hence the number of days in the year, for which habitability would be possible.
 * None of this conflicts with the well-known fact that in the very long term the stability of the Solar System is not assured, as illuminated by Chaos theory. 87.81.230.195 (talk) 14:49, 25 May 2010 (UTC)


 * Note that a light-year is the distance which light travels in a vacuum in one Julian year (astronomy) which is 31,557,600 SI seconds (with each second defined as "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom"). This measure of time is not dependent on the length of sidereal year which is not even now precisely equal to the Julian year (astronomy). 124.157.249.129 (talk) 15:05, 25 May 2010 (UTC)


 * When I say "innate=constant", I consider Newton's total energy expression: Etot=Ekin+Epot=Ct, where Ekin=1/2*m*Vr^2+1/2*I*w^2. All V=Velocity related values are evaluated according the new second. So, 1/2*I*w^2 is constant, was (innate), today or 4 billion years ago and this represent what we call "day" in Newton's expression. 1 year is the time for 1 cycle of the Earth around the SUN. Practically, we say this time is 365 days. Year's lengths are "not innate" but variable according the distance of the planet to the SUN.(Kepler's period law). As a possibility of 1 year=345 days is considered, I say "light-year" distance has no sense, but ligth-second distance should be defined. Say 3600*second=1 day=innate=Constant. Then we must use Ligth-day or 1000LD distance in astronomy; not ligth-year. Now, coming back to our Adam's 930 years living, it seems that this is possible if we agree on "variable year lengths". Suppose the human life is 100 fictive Earth's years, today. 100 Earth's years=36500 today's Earth's days. If we were living on Saturn, according Kepler's period law, we will live only ....Saturn's years. Are there any old Earth's periods, where Adam has lived 930 cycles corresponding to today's 100 cycles of the Earth around the SUN? That may explain Adam's and others long life. And probably Adam (homo sapiens) has lived at a period where 930*P=36500 fictive days.Then P=39 days/ a cycle. Mathematically this is possible, but physically it looks impossible. Is it really impossible? TASDELEN (talk) 18:53, 25 May 2010 (UTC)


 * No, there has never been a time when the Earth revolved around the Sun 9.3 times faster than it does now (which would require it to orbit only about 30 million miles from the Sun, closer than Mercury). In any era that Homo sapiens has existed (no further back than 1.5 million years using the most generous definitions) the year length has been very close to today's value, so shorter actual years cannot in any way explain the Bible's supposed lifespan values. The fact that in the remote past the Earths axial spin was faster, so that there were more but shorter days in the year, is quite irrelevant to this question, as is the way we define the distance we choose to call a light year (which you have misunderstood, please re-read 124.157.249.129's correct explanation above). 87.81.230.195 (talk) 21:24, 25 May 2010 (UTC)


 * Most certainly, people back then were not thinking about velocity of photons or even the rotation of the Earth. Most of the stories where these "timing problems" are present are set in a time when people were not much more than hunter-gatherers. How could they measure years and moths? How could anyone of us, without extensive knowledge of astronomy and without the help of the organized society around us know the exact month we are in or your exact age? Especially in a region without observable change of seasons? How could you measure time frames longer than the day based on things that really interest you? Maybe after the harvest seasons of certain plants? Migration patterns of certain animals you hunt? A year could mean pretty much anything, and most stories before the time of Moses are probably set many centuries apart from each other. Besides this, many people assume the language, way of thinking and memes were exactly the same as today. It's like if you write down that you've seen dozens of something, and many centuries later someone reads it, looks up what "dozen" could have meant, does a research about the things you've seen, discovers that their number was not exactly divisible by 12, and reaches the conclusion that you were a big liar. --131.188.3.21 (talk) 22:39, 25 May 2010 (UTC)


 * Numerology was common. A lot of the age spans are probably numerological.  Clearly, for example, the 500/600 year motif in the story of Noah is numerological.  Also, there are probably clues embedded for the use of ancient scholars but hidden from the common people; for example, the math indicates that Noah's father (Lamech) and grandfather (Methuseleh) both died the year of the (fictional) flood, circa 1656 years after creation ... perhaps masking via allegory a more ancient historical story of a dynastic rivalry.  (The preceding is from memory; a detail or two may be wrong.)  Perhaps, too, "sacred" science was encoded.  The oldest figure is Methesuleh; Methuseleh's age, if expressed in lunar months (circa 27.321 days) rather than years, equals the number of years necessary for the equinoxes to precess exactly one degree.  Of course, we presume this figure was unknown to the authors. 63.17.33.231 (talk) 11:44, 26 May 2010 (UTC)


 * Yes,User:Dolphin51.I want to believe to the Old Testament citations on ages,and I am searching a mathematical model to explain these sentences.I am Muslim=very good Christian of the time of Jesus=believer of Mooses= from the religion of Abraham= God religion.I am sure a mathematical relation should exist between the ages and the periods of the Earth around the SUN.I don't think the periods were constant since the existence of the Earth.A new theory? TASDELEN (talk) 19:03, 26 May 2010 (UTC)


 * A correction: 3600seconds*24hours*365,25days= 1Julian year. When (365,25) is a fixed value, the light-year distance has a fixed value. If, or when a year was 345 days will the ligth-year mean the same distance ? Of course, not. Then, ligth-year definition is inappropriate to measure astronomical distances; while I*w^2 is constant, is innate (any question?). This why, I propose the use of light-day or 1000LD distances for astronomical measurements.Otherwise we should agree that from the existence of the Earth until its collision with the SUN (end of the Earth) years have 365,25 days.And in this case never a collision will occur,as 365,25 is the period of 1 cycle of the Earth around the SUN.Periods should change,should go bigger and then diminue (within 5-6 billion cycles) with time. TASDELEN (talk) 20:54, 26 May 2010 (UTC)
 * So, I think most people on the science ref desk will not agree with you. It is a fallacy in science to START with a conclusion and then try to fit reality to your conclusion. Yes we agree there are issues using ANY reference point. Even our galactic co-ordinate system has problems with drift over long periods of time. It doesn't matter WHAT you use as a point of reference, it is an issue that needs to be taken into account and scientists understand that, that's all there is to it. Scientists aren't going to change the astronomical scale so that it fits better with an account from the bible. That's not to say it will never change, but I guarantee that won't be that reason. I think this discussion has gone on long enough already. Vespine (talk) 02:11, 27 May 2010 (UTC)


 * I think,I find a math which fit the physics: Newton's law F*dt=m*dv. From this physical law, I will deduct Bible's "Adam 930 years of age". Will this reasoning be a fallacy? You will decide.

F*dt=m*dv means  F*r*dt=m*r*dv ( energy conservation equation). So, we write

1/2*m*Vr^2+m*gr*r+1/2*I*w^2=m*r*dVr (total energy with g variable;and Vr=radial velocity) This is a differential equation

dr^2+K*dt^2=2*r*d(dr) with solution

r=-a*t*(t*tmax)+K where K=2*gr*r+I*w^2/m=-a^2*tmax^2/(1+4*a)

On Cartesian, the graph of (r) is a parabola.

On Polar this graph is a cardioidal looking spiral: billions of spirals. Expanding then after compressing; with a max.point, only one max.point.

This is the shape of the orbits. No sign of ellipse, no sign of aphelion, no sign of perihelion.A new theory for "orbits" !!!!. Expansion and compression of the spiral ring's amplitude means "variable cycling period".In this concern,the creation of the Earth is due to a "small bang" of the SUN which ejected the planets and other celestial bodies of the Solar system.The "variable cycling periods" is due to the constant,innate, I*w^2.That means Vp perpandicular to Vr is "invariable". Then,"Adam's 930 cycles" may fit a period of P*930=36500 days (considering today's 100 cycles for Adam life).That is P=39 days/a cycle.And this period existed 4 344 656 600 cycles ago,approximately.According this evaluations "homo sapiens" should have existed so long time ago.TASDELEN (talk) 07:41, 27 May 2010 (UTC)
 * So instead of taking the knowledge we have of how long a human can live and turning it on its head to fit your conclusion, you're going to take all of cosmology and turn it on its head instead? Why bother? Just say Adam lived 930 years, you only have to break one rule then instead of rewriting the entire solar system; and God did it anyway, so what's the problem? You seem exhibit very little faith for someone trying so hard to reconcile God's "actions". I've said about all i have to say on this subject, if you want to debate this subject more I suggest you seek out one of the many discussion forums around the internet as a more appropriate place for these kinds of discussion. If you have any more specific questions about planetary orbits or something else sciency, feel free to start a new section and ask away.  Vespine (talk) 00:45, 28 May 2010 (UTC)


 * ThanksVespine. Your's "There's no evidence that the Earth shuffled around or changed places since the formation of the solar system, there may have been some catastrophic events which changed the year a bit, but there's some decent evidence that the Earth has been at least in the Habitable zone, since life arose anyway" is a canonic sentence. As an alternative, I proposed Newton's F*dt=m*dv which gives r=-a*t*(t*tmax)+K (may be wrong!) from where I evaluated mathematically (not physically) the age of ADAM. That means "Earth is changing places" is a non-canonic statement, and it is difficult to change the perception of the community with such reasoning.It was nice to communicate with you.Thanks again. TASDELEN (talk) 21:22, 28 May 2010 (UTC)


 * I think we have shown elsewhere that your mis-derivation of "spiral orbits" (in contradiction of Kepler's laws and the observations of Tycho Brahe) just don't make sense, so they cannot explain varying "years". There is quite a lot of science that it is worth challenging, but I don't think you have the remotest hope of creating a new mathematics of orbital motion.  Too many mathematicians have understood the derivation, and too many observations have confirmed that they are valid.  Sorry.    D b f i r s   15:32, 29 May 2010 (UTC)

You have shown nothing. You did not considered my derivations.(even they may be mis-derivations). You did not pointed out the false steps of my derivations. You just copy-pasted ellipse article from WİKİ, as a proof. According me Wiki's proof of orbital motion is wrong, since Vp perpandicular velocity to Vr (radial velocity) is asumed to be variable, and I say constant. If you prove that Vp velocity is variable, then Newton's energy conservation expression should be refused. You are refusing Newton's F*dt=m*dv. Sorry. TASDELEN (talk) 18:59, 29 May 2010 (UTC)
 * No, D b f i r s  

No Tango.The statement (1/2*m*Vr^2+m*gr*r+1/2*I*w^2=m*r*dVr) is correct as it is the energy conservation expression. With the following correction (K/dt^2=m*gr*r+1/2*I*w^2) we write: 1/2*m*(dr/dt)^2+K/dt^2=m*r*d(dr/dt)/dt which is,after simplification:
 * And I copy-paste the following discussion paragraph,for your control:

r'^2+2*K/m/dt^2=2*r*r" a differential equation (with all the terms of the same size,same order) having the solution:

r=-a*t^2+a*t*tmax+K where K=-a*tmax^2/4=Constant.In fact:

dr/dt=r'=-2*a*t+a*tmax

d(dr/dt)/dt=r"=-2*a

r'^2=4*a^2t^2-4*a^2*t*tmax+a^2*tmax^2

2*r*r"=-4*a*(-a*t^2+a*t*tmax+K)=4*a^2*t^2-4*a^2*t*tmax-4*a*K which is ending by:

4*a^2t^2-4*a^2*t*tmax+a^2*tmax^2+000000=4*a^2*t^2-4*a^2*t*tmax-4*a*K and after simplification

a^2*tmax^2=-4*a*K and K=-a*tmax^2/4 (as I have posed=Constant).

All this has one meaning: [r=-a*t*(t*tmax)+K] and the graph of this equation is a spiral on Polar plane.Not an ellipse.I think Kepler's laws of planetary motion#Derivation from Newton's laws should be revised for (Derivation) and should not be copy-pasted as icon. I insist: either Newton's law indicates my solution or the solution of Zunaid. I need mathematical proofs, confirmations, and not discouraging sentences like they don't have a grasp of English. What about your Turkish? Meanwhile, a difficult question about Kepler's area law: do you believe to the derivations on Wiki? Is Vp perpandicular velocity to Vr (radial velocity) variable or constant? Wiki says: variable. I say constant. Thanks.TASDELEN (talk) 13:10, 28 May 2010 (UTC).TASDELEN (talk) 08:10, 30 May 2010 (UTC)


 * No comments from Wiki administrators? Which administrators are refusing Newton's law of F*dt=m*dv? No one ? Very good, then consider please Wiki's derivations correctness about the orbital motion of the planets: see if Vp is constant or not. According me Vradial is variable, Vperpandicular is constant. And a simple proof of this is as follows:

V^2=Vr^2+Vp^2 (Vorbital^2=Vradial^2+Vperpandicular^2)

1/2*m*V^2+m*gr*r+1/2*I*w^2=Ct (total energy equation with variable g,and innate I*w^2)

(Vr1^2+Vp1^2)+2*m*gr1*r1=(Vr2^2+Vp2^2)+2*m*gr2*r2 (equality at#1 and #2 position)

Vp doesn't change the equality of the energy conservation equation,So

Vr1^2+2*m*gr1*r1=Vr2^2+2*m*gr2*r2 and this means  Vp1=Vp2=Vpn=Ct

And saying so, dVp/dt=0

Wiki says d(r*Vp)/dt=0 and deducts "areas equality laws". Wiki is wrong. Administrators should comment this math. The orbit of the planets is a spiral situated on a paraboloid surface along the trajectory of the Sun in its galaxy, expanding and then compressing.For this look please to some galaxies photos from Nasa. New theory on cosmology !!!!No reference,no back ground,but Newton's laws derivations.TASDELEN (talk) 22:01, 31 May 2010 (UTC)

TDS
Say one has a geophysical electric log with data for SP, short number (16), long number (64), and what one wants to do is to calculate/estimate the TDS (Total dissolved solids) -- water quality -- from that data. How does one go about doing that? Killiondude (talk) 22:14, 24 May 2010 (UTC)


 * This link may be of some help, although it points out that it can be used in this way provided that the analysis is tied closely to local water chemistry measurements. Mikenorton (talk) 19:32, 25 May 2010 (UTC)
 * Thanks! Killiondude (talk) 19:11, 26 May 2010 (UTC)