Wikipedia:Reference desk/Archives/Science/2010 April 6

= April 6 =

Terraforming Venus
The first problem for colonizing Venus would be the immense atmospheric pressure. Venus itself is slightly smaller than Earth, so I assume it isn't the increase in the solid mass that is causing the pressure? Is it simply the density of the atmosphere that causes the pressure? According to our article it's about 2.5 times thicker than our own. How might we reduce the size of its atmosphere? Could we somehow siphon it off into space? Perhaps we could transport it to Mars to help build an atmosphere there?

Next is the composition of the atmosphere. How might we dispose of all the harmful gases such as sulpher dioxide and hydrochloric acid? Then there's also the carbon dioxide. There is a huge selection of life from our planet that would be capable of converting this carbon dioxide into oxygen, but the problem is none of it can survive the extreme temperatures of Venus, which are caused by all that CO2. We're in a catch 22, we need to get rid of the CO2 to make the planet habitable, but we can't get rid of it until it is habitable. Not even hyperthermophiles could survive those temperatures. So what could we do? Apparently the temperature in the area from 52.5 to 54 km above the surface has temperatures of 20- 37 degrees Celcius, with pressure only slightly lower than that of Earth. We might grow plants in this area, but how could we suspend them at that altitude?

Then there's the massive amount of volcanic activity ready to undo any changes we make to the atmophere. Is there any way we could control this? I can't think of anything at all.

And finally there's the magnetic field. According to our article on the subject the only reason for the lack of a magnetic field on venus is the lack of convection in the mantle; i.e. the mantle and core are at comparable temperatures. How might we create a temperature difference? Nuclear weapons?--92.251.137.62 (talk) 00:08, 6 April 2010 (UTC)


 * I think we should wait until after Mars is fully terraformed to even think about doing Venus. They only part I can answer is that we could use blimps to hold plants in the upper atmosphere.  They could be black on top to absorb solar heating and could also be filled with lighter gases. StuRat (talk) 00:22, 6 April 2010 (UTC)
 * I think it might be an idea to merge the moon and mercury into mars to make it bigger so people don't have to adapt to life on earth.--92.251.137.62 (talk) 00:27, 6 April 2010 (UTC)
 * Do you know how much energy you would need to get the Moon and Mercury into Mars' orbit? And then you have the problem of merging them without just destroying them all. It is completely impractical. --Tango (talk) 00:44, 6 April 2010 (UTC)
 * I think it's obvious from the title that this is completely hypothetical and certainly won't be possible, never mind practical, for probably thousands of years. C'mon I'm sure you can use your imagination.--92.251.137.62 (talk) 00:50, 6 April 2010 (UTC)
 * Plus, taking the Moon away from the Earth could cause all kinds of nasty consequences for us here on Earth (like changing the Earth's rotation speed, messing up the magnetic field, major climate change, etc.) Definitely not a good idea, even if it was remotely possible. 24.23.197.43 (talk) 05:04, 6 April 2010 (UTC)
 * If you have the energy available to move the Moon into Mars' orbit, then you can easily deal with those problems. --Tango (talk) 15:17, 6 April 2010 (UTC)
 * If people are interested, moving the Moon from Earth's orbit to Mars' orbit, ignoring the Earth and Mars and just considering the Sun and Moon, would take the total energy produced by the Sun, emitted in all direction, for 16 hours. That is a ridiculous amount of energy. --Tango (talk) 15:27, 6 April 2010 (UTC)
 * Not that it matters, but I got 59 hours. Dragons flight (talk) 18:39, 6 April 2010 (UTC)
 * Same order of magnitude, so close enough! --Tango (talk) 21:47, 6 April 2010 (UTC)
 * While you might be able to fix the problems involved with removing the Moon, a much lower tech level could just skip the Moon itself and crash Mars's moons onto the surface and bring some of the larger asteroids from the (relatively) nearby asteroid belt in to add mass. No need to fsck up the Earth and expend huge amounts of energy to enable the Moon to escape Earth's gravity when you've got a whole asteroid belt to cherry pick. Hell, with the asteroid belt, you just have to decelerate an asteroid at the right time and the Sun's gravity will do the work for you. With the Moon, even with near perfect timing to maximize the use of a slingshot maneuver using the Earth's gravity you'd still be fighting the Sun the whole way. &mdash;ShadowRanger (talk 18:46, 6 April 2010 (UTC)
 * Moving closer to the Sun is no easier than moving further away. In one you have to accelerate the object and in the other you decelerate it, but that's the same thing as far as energy is concerned. Also, the total mass of the asteroid belt is only 4% that of the Moon (and Mars' moons don't add much to that). --Tango (talk) 21:47, 6 April 2010 (UTC)
 * See Terraforming of Venus. There are various ideas there on how to do it, but none of them particularly feasible, even assuming reasonable future technology. --Tango (talk) 00:44, 6 April 2010 (UTC)

seeing red
I happened to be on a path with a translucent green roof. After getting out of the path it seems that all that I look at have a tinge of red. The same thing happened when I was looking on an translucent orange window of a jeepney but it seems that other things I look at this time have a bluish tinge.--121.54.2.188 (talk) 01:49, 6 April 2010 (UTC)


 * See afterimage, or more generally, sensory adaptation. TenOfAllTrades(talk) 02:06, 6 April 2010 (UTC)


 * Your eyes have red, green and blue sensors - when you see a lot of one color, the brain dials down the output of sensor(s) that pick up that color. When you  step out into normal light, it takes a while for the brain to adjust - and hence, everything takes on a tinge which is complementary color of the one you'd been looking at before.  So in green light, your green sensors are dialled down.  When you step into white light, green is suppressed and everything is seen in red/blue only.  The color that is a mixture of red and blue is "magenta" - which is a reddish purple.  Orange (which is really dark yellow) is a mixture of red and green - so in yellow/orange light, the red and green sensors are suppressed - and when you enter white light, the blue sensors are the most active.  Hence, the colors you saw pretty much exactly fit the theory.  The effect fades over maybe 10 seconds as your eyes return to normal.


 * You can do an experiment to prove this. Click a couple of times on the image at right until it's only thing in your browser window - make the window full-screen.  Now, stare fixedly at the nose for a full 30 seconds - then immediately look at the blank part of the screen.  You should see a 'normal' colored  picture of our glorious leader.  This works because the picture at right is a colored "negative" of the desired image.  When our eyes start to shut down the blue sensors - we'll see flesh-tones. (You may need to quickly blink to see it a little better.)
 * SteveBaker (talk) 02:32, 6 April 2010 (UTC)


 * I read once that one reason for Scrubs (clothing) being green was to reduce the distraction of green afterimages from extended staring at brightly lit surgical procedures. Our article on scrubs does not mention that particular reason, might try to see if I can find a source later. Vespine (talk) 04:39, 6 April 2010 (UTC)


 * Oh! To contrast with all of that red blood splattered everywhere?! Well, it's possible I suppose.  So I suppose the reason all of the security guys on the Starship Enterprise wear red is to avoid this exact effect when massacring Romulans? SteveBaker (talk) 13:17, 6 April 2010 (UTC)


 * I think they are designed to contrast with blood, but so that you can tell if there's blood on your scrubs and change them before infecting other patients. Blood also shows up nicely against a traditional white nurse's uniform.  However, now they prefer patterned prints, which seem more designed to hide contamination than to make it obvious. StuRat (talk) 13:55, 6 April 2010 (UTC)

You can tell that white light stimulates blue sensory receptors more because when you are in bright light and go into a dim room, every thing has a bluish-violet tinge. --Cheminterest (talk) 20:29, 7 April 2010 (UTC)
 * Not really. There is actually a much more complicated reason for that...it's to do with the shift from 'Mesopic vision' to 'Scotopic vision' and an effect called the Purkinje effect.  This becomes a very complex topic once you really start digging into it.  But in normal light levels, our eyes are actually quite a bit less sensitive to blue than to red and green light...but our brains are good at compensating for that, so it's not something you generally notice.  But if you look at the image at right, you'll see that the blue patch looks much darker than the green...that's not an artifact of picture - or your computer screen - its your eyes!  SteveBaker (talk) 02:35, 8 April 2010 (UTC)

What causes color?
Color is clearly determined by what wavelengths of light are transmitted off an object, but why do things absorb certain wavelengths and reflect others? Why, for example, are crystals of copper sulfate pentahydrate brilliant blue (while its anhydrous form is white), rather than any other color (or colorless)? Color clearly depends to some extent on structure, as evidenced by the various allotropes of phosphorous or the copper sulfate example above, but then again, just loose nitrogen dioxide molecules floating around make a brown gas. On a related note, what would cause something like glass to be transparent and colorless? Thegreenj 02:20, 6 April 2010 (UTC)


 * The article on Transparency and translucency probably answers all of your questions. It is a pretty good introduction to the physical properties of color and light from what I can see.
 * Note of course, unstated above, is that it is the brain that translates wavelengths into what we call "colors" (which is a perceptual property, not a physical one). So to be perfectly consistent, you'd want to not say "brilliant blue" but "reflects EM waves in the (insert measurement) range." It's the brain that makes it "blue", based on its interpretation of signals from your eye hardware. (The brain could be wired differently—some animals can't distinguish between wavelengths that humans can, and can see some wavelengths that humans can't.) --Mr.98 (talk) 02:39, 6 April 2010 (UTC)


 * As for colors, each atom has a bunch of electrons at a small number of specific energy states (called quanta), Light hitting them causes them to change energy states, and when they return to the original state, they radiate photons at specific frequencies, or colors.   This is part of quantum mechanics. StuRat (talk) 13:30, 6 April 2010 (UTC)


 * A minor (but important) quibble &mdash; quanta (singular quantum) are discrete packets of energy (generally associated with transitions between energy levels), not the energy levels themselves. That is, photons are quanta of electromagnetic energy.  In a system that can be modelled as having discrete energy levels (as in the example of electrons bound to an atomic nucleus), one can describe the associated energy levels as quantized; the arrangement of electrons (which will determine the system's energy) can be described as its quantum state.  TenOfAllTrades(talk) 14:09, 6 April 2010 (UTC)

Thanks for the responses! One more follow-up question: are there models that can be used for theoretical predictions EM absorption/emission based on a molecular structure? Thegreenj 02:57, 7 April 2010 (UTC)


 * Yes, I believe there are. StuRat (talk) 10:39, 7 April 2010 (UTC)

What's the nasty stuff in coal ash?
Could someone who can read this paper please list the "minerals and leachable metals" it names as primary sources of toxicity? 99.25.114.26 (talk) 07:53, 6 April 2010 (UTC)
 * What is leachable is going to depend on what is in the coal and slag to start with. See Fly_ash, etc.--Aspro (talk) 08:15, 6 April 2010 (UTC)
 * Oh, great, you just happened to catch me reading up on coal-to-liquids technologies! Well, since these topics are closely related, I'll tell you what my source (Higman and van der Burgt) says about leachable toxic metals in coal ash.  Here's a comprehensive list of the toxic metals and their concentrations:


 * Arsenic, 2.1 ppm (volatile)


 * Boron, 35 ppm (relatively nontoxic)


 * Barium, 130 ppm (but not all of it is in leachable form)


 * Beryllium, 1.2 ppm


 * Cadmium, 0.07 ppm (volatile)


 * Cobalt, 3.5 ppm (somewhat radioactive; volatile if reduced)


 * Chromium, 7.0 ppm (only slightly leachable if reduced)


 * Copper, 9.2 ppm


 * Mercury, 0.13 ppm (volatile)


 * Manganese, 84 ppm (not very toxic)


 * Nickel, 10 ppm (volatile if reduced)


 * Lead, 14 ppm


 * Antimony, 0.57 ppm (may be volatile if reduced)


 * Selenium, 3.1 ppm (volatile)


 * Strontium, 316 ppm (radioactive)


 * Thorium, 8.4 ppm (slightly radioactive, nonleachable)


 * Uranium, 2.1 ppm (radioactive, practically nonleachable)


 * Vanadium, 17 ppm (partially leachable)


 * I should also mention that most coal-to-liquids processes are much better environmentally than conventional coal-fired power stations, because they produce little if any fly ash, and because the bottom ash comes out in the form of an inert non-leachable slag that traps all the toxic metals instead of spreading them far and wide. As for the volatile metals, instead of simply being dumped into the atmosphere as in a conventional power plant, they enter one or more of the gaseous byproduct streams, from where they can be scrubbed relatively easily.  Coal-to-liquids also allows the sulfur to be removed and recovered almost completely, because it's removed from the coal as H2S, which is readily scrubbed from the off-gas stream by a wide variety of methods, and can be converted to elemental sulfur, whereas in a conventional plant, it goes into the flue gases as SO2, which can only be recovered as calcium sulfate, a relatively low-value material.  24.23.197.43 (talk) 09:00, 6 April 2010 (UTC)


 * See also Polycyclic aromatic hydrocarbon, soot, and fly ash. 92.29.111.79 (talk) 22:42, 6 April 2010 (UTC)


 * Soot and PAHs are not metals and therefore are technically outside the scope of this discussion; however, they are indeed found in fly ash and are potentially harmful to human health. (Note also that coal-to-liquids technology allows these to be recycled to extinction, which is rarely if ever possible with conventional coal-burning technology.) 24.23.197.43 (talk) 01:17, 7 April 2010 (UTC)
 * The OP asks "What's the nasty stuff in coal ash?" 78.149.173.243 (talk) 15:06, 7 April 2010 (UTC)
 * True, but then he/she specifically asked about "minerals and leachable metals". FWiW 24.23.197.43 (talk) 05:31, 8 April 2010 (UTC)

2012-- mayan civilization
is the hoax about the end of earth in any scientific way correct? if its so what scientists are doing to save the earth?--Myownid420 (talk) 12:45, 6 April 2010 (UTC)
 * See Mesoamerican_Long_Count_calendar, which states "...stated that "We have no record or knowledge that [the Maya] would think the world would come to an end" in 2012. As well as 2012 phenomenon.  Dismas |(talk) 12:50, 6 April 2010 (UTC)
 * No, and consequently, not anything they don't do anyways. See http://www.2012hoax.org/ for detailed rebuttals of all the various doomsday fantasies. --Stephan Schulz (talk) 12:52, 6 April 2010 (UTC)


 * The Mayan clock has a whole bunch of cycles built into it. These are like the hands going around on a modern-day clock - or the cycles we have of months, years, decades, centuries and millenia.  For the Mayans, 2012 would be like the end of a millenium for us.  Of course, quite a few nut-jobs thought the world would end on Jan 1st 2000, but the Mayan calendar is even more attractive to those kinds of people because it's that little bit more obscure.  The Mayans didn't predict that the world would end - and even if they did, what the heck did they know that we don't?  The world (and the universe in general) are ruled by 'chaotic' (in the mathematical sense) systems.  Making any precise predictions (to within an accuracy of a single day) for more than a few tens of years into the future is essentially impossible - not just because we can't measure things that accurately - but also because the fundamental mathematics of chaos theory doesn't permit that kind of precision.


 * So the Earth doesn't need saving (well, not from the first cycle of the Mayan calendar ending). Hence, scientists aren't doing anything special because of it.  Now, can we all please go back to worrying about our lack of defense against killer asteroids, or the all-too-real certainty of disasters from global climate change and the certainty that we're about to run out of materials like copper that are essential to our present way of life?  If the general public spent half as long worrying about those things as they do about ridiculous nonsense like Mayan calendars, the world would be a much more secure place! SteveBaker (talk) 13:09, 6 April 2010 (UTC)


 * You might be interested in a similar discussion over at Wikiversity, which focuses on the "galactic alignment" around that date: . StuRat (talk) 13:10, 6 April 2010 (UTC)


 * That's nuts! Nothing else in our galaxy is remotely close enough to affect us - and any alignment would be tough to define given all of the speed-of-light issues involved.  Also, things move so incredibly slowly that if some grand alignment were happening in just a couple of years, we'd already be feeling whatever effect there is supposed to be.  "Galactic alignment" is a deeply stupid idea! SteveBaker (talk) 03:24, 7 April 2010 (UTC)


 * I don't think gravitational effects are relevant, it's meant to be some type of "sign from God that Armageddon is approaching". Not that I believe any of it, of course. StuRat (talk) 10:27, 7 April 2010 (UTC)


 * But given that assumption, what makes anyone imagine we'd get any warning? God could snap his/her/its' fingers/hooves/tentacles at any time and end the universe.  This is why we call unpredictable events "Acts of God". SteveBaker (talk) 20:23, 7 April 2010 (UTC)


 * Perhaps the god(s) are giving humanity time to repent ? In any case, various holy books talk about signs coming before the end, although I don't know of any that mention galactic alignment specifically. StuRat (talk) 15:19, 8 April 2010 (UTC)


 * Even assuming that global climate change is happening like they say and will lead to big disasters for the civilized nations somewhere down the road (and there is real dispute about both these claims), it's not nearly as immediate as the threat that global jihad poses to our freedom and our way of life. If the public spent more time worrying about that danger and less time about stuff that won't happen until many years from now, we would all be much safer. 24.23.197.43 (talk) 01:26, 7 April 2010 (UTC)


 * I really don't agree about that. Sure, the terrorists can make a lot of trouble - but I don't see them being able to produce world-wide "end-of-world" types of effects.  Even the worst-case scenario of them getting hold of a nuclear weapon would likely only take down one city - it would be tremendously upsetting and even somewhat disruptive - but life would go on in pretty much the same way elsewhere.  I would expect to see chaos on the scale of Hurricane Katherina...possibly more if it were NewYork, Washington or someplace like that - but it's not an end-of-world scenario.  Incidentally - if you still don't believe that Global climate change is real - you should maybe actually read that article you linked to. SteveBaker (talk) 03:24, 7 April 2010 (UTC)


 * Steve, according to the latest Rassmussen polls, most Americans disagree with you about global warming. As for global jihad, have you considered that if Pakistan decides to make a nuclear terrorist attack, they could blow up several atom bombs in different coastal cities at the same time Al-Qaida fashion and not only destroy several cities at the same time but also cripple our foreign commerce for up to several years, with devastating economic consequences?  No, it wouldn't be the end of the world, but pretty darn close to it.  Also, by "global jihad" I mean not just terrorism, but also "stealth jihad" (meaning efforts by Islamic organizations to pass Sharia-type laws in a number of Western nations, including the USA).  This is possibly an even bigger danger in the long run than ordinary terrorism, even of the mass-casualty variety. 24.23.197.43 (talk) 05:50, 8 April 2010 (UTC)
 * Sure and as I suggested below, Barack Obama or the Russian top brass could do far, far worse. Does it mean it makes sense for us to spend a lot of time worrying about such possibilities? Not really. Your claims of stealh jihad are even more nonsense without any evidence. And frankly, I don't really care what most Americans believe. Most Americans don't believe in evolution either despite the fact I can count on the fingers of my hand the number of biological scientists who actively dispute it. What most people believe clearly doesn't tell us much about reality. Nil Einne (talk) 16:11, 10 April 2010 (UTC)


 * Indeed many would argue people are already way too worried about 'global jihad' in comparison to the actual threat posed. And even without "end of world" type effects, you only need one or two major natural disasters or starvation in a few places for the number of deaths resulting from global warming to dwarf anything from 'global jihad' to now Nil Einne (talk) 07:57, 7 April 2010 (UTC)


 * Nil Einne, the danger from global jihad is not just people getting killed, but even more so the fact that the Islamics' ultimate goal is to eliminate secular democracy and replace it with totalitarian Islamic fundamentalism. See my reply to Steve Baker, just above your comment. 24.23.197.43 (talk) 05:50, 8 April 2010 (UTC)
 * There is little evidence for your claims that it's the goals of most let alone all people involved in 'global jihad', and little evidence there is significant risk so... Nil Einne (talk) 16:11, 10 April 2010 (UTC)
 * That's what the definition of jihad is -- a holy war for the purpose of spreading Islam. Did you just not know this, or are you purposely muddling the issue in order to minimize the threat of jihad?  (BTW, your user page says that you're from Malaisia, which is a majority Islamic country, so...) 24.23.197.43 (talk) 02:52, 11 April 2010 (UTC)


 * Obviously. 9/11 did not even make a blip on world-wide death rate. Katrina alone killed 1800+ people, nearly 2/3rds of the direct deaths toll of 9/11. The 2010 Haiti earthquake killed between 30 and 100 times more people than 9/11, and the 2004 Indian Ocean earthquake was of the same order of magnitude. Terrorists simply do not play in the same ballpark - it needs a evil empire to compete. --Stephan Schulz (talk) 12:33, 7 April 2010 (UTC)


 * Just because terrorists haven't killed millions yet, that doesn't mean that they won't some day be able to, with nuclear and biologic weapons. StuRat (talk) 15:11, 8 April 2010 (UTC)


 * Thanks for the common sense, StuRat -- this should be obvious to everyone, even someone as out of it as Stephan Schultz. Clear skies to you! 24.23.197.43 (talk) 00:13, 9 April 2010 (UTC)
 * Sure, and Barack Obama and the top brass in the US could go nuts and decide to take out the whole world in our foul swoop. That doesn't means we should spend all our time worrying about this possibility when there are far bigger problems to worry about Nil Einne (talk) 16:11, 10 April 2010 (UTC)
 * Sure, they could nuke the whole world, but the question is, why the bloody hell would they? There's no plausible motivation for them to do that, and you know it!  On the other hand, Ole Goatface would surely nuke everyone in America if he could, but fortunately he can't (thank God for that!) 24.23.197.43 (talk) 02:52, 11 April 2010 (UTC)


 * Stephan Schulz, how DARE you call my wonderful country an "evil empire", you stinking anti-American bastard?! If you don't agree that terrorism is a significant threat, you're welcome to say so and give whatever evidence you have to support your views, but don't you dare insult the best nation in the whole wide world, you son of a witch!  24.23.197.43 (talk) 05:50, 8 April 2010 (UTC)


 * I didn't. You deduced this from the links I gave. What does that tell you? --Stephan Schulz (talk) 06:21, 8 April 2010 (UTC)


 * Oh yes you did, you low-down liar -- the links clearly imply that (according to you) the USA is an "evil empire" because of the Iraq war! Don't you try to say one thing one day and deny you ever said it the next day, your statements are on public record here and smart people can see right through your obfuscation!  Now, get lost! 24.23.197.43 (talk) 08:05, 8 April 2010 (UTC)


 * "the links imply" - that's the point. --Stephan Schulz (talk) 08:16, 8 April 2010 (UTC)


 * That's rubbish and you know it -- the articles you linked merely state the claims re. the Iraq war, it's YOUR choice of words for the links that implies the conclusion (namely, that the USA is an "evil empire"). Stephen Schultz, you can try to bullshit everyone with your word games like some sleazy lawyer from a pulp-fiction novel, but over the past year or so I've learned to see right through your tricks!  And FYI, if you tried this kind of sophistry in an actual courtroom, I bet you all you want that you'd be disbarred before you can say "cat in the hat"! 24.23.197.43 (talk) 00:13, 9 April 2010 (UTC)


 * Uh, boy. Let me point out that in most religious traditions (the Mayans included, as best I can tell) the 'end of the world' is a 'human' event, not a 'world' event. It usually means a broad sea-change of some sort in the nature of human society.  Only the far fringe of religious ideology interprets the end of the world as a physical ending to the world.


 * Frankly (as an American) I am far more concerned about the actions of powerful nations than of terrorists and small nations. Even considering a world in which Pakistan, Iran, and North Korea have nuclear weapons, the maximum yield they could produce would (at best) kill a few million people and stir up a whole lot of drama - they do not have the resources to pose a serious threat to modern society.  Terrorists are even weaker, and despite their supposed goals are basically incapable of changing the social order directly.  however, the US, China, and Russia (for the short list) have the resources to make the world largely unfit for human life, either through warfare or through industrial and commercial pollution.


 * And IP-person: chill out the jingoistic crap. -- Ludwigs 2  15:58, 8 April 2010 (UTC)


 * First tell Stephan Schulz to quit his America-bashing crap, and then you can tell me to chill out the "jingoism", as you put it. He's the one who started this whole shouting match by calling our country an "evil empire" -- just check out his first comment in this section.  And BTW, you're wrong to worry about nuclear warfare between civilized nations like the US, China and Russia 'cause they're all smart enough to know better than to start a nuclear war among themselves (which is not the case for Iran and Pakistan). 24.23.197.43 (talk) 00:13, 9 April 2010 (UTC)
 * Ok listen, just because someone on here says something you disagree with doesn't give you a free pass to completely flip out.
 * That said, the claim that the US is an evil empire is pretty silly if you know anything about US politics. We may do things that are belligerent and harmful, but it's not intentional harm and it's not as if we've been profiting off these blunders.  These recent wars have cost the US hundreds of billions of dollars, thousands of lives, and were initiated at least with the expectation by those who supported them that they would make the world at large more safe.
 * But I laughed out loud when I read "the threat that global jihad poses to our freedom." Are you talking about how the terrorism obsessed are undermining the rule of law in the name of security?  Also do you seriously think that a poll of Americans provides evidence for or against the existence of human caused climate change?  Maybe Rasmussen can tell me about the Higgs boson too.  That would be much cheaper than this whole LHC thing. Rckrone (talk) 07:31, 9 April 2010 (UTC)
 * I've clarified this already in plain English, that by "jihad" I meant not just terrorism, but also "stealth jihad" (i.e. efforts by Islamic groups to lobby for Sharia-type laws in Western nations). Those efforts, not terrorism, are the main danger that Islam poses to freedom.  Can't you read simple English? 24.23.197.43 (talk) 04:55, 10 April 2010 (UTC)
 * Again please provide some evidence for your claims of this supposed risk due to 'stealth jihad', or stop talking such nonsense. Perhaps you really should have left when you said goodbye? Nil Einne (talk) 16:11, 10 April 2010 (UTC)
 * OK, I'm going by memory here, but this was in an accredited news source from Minnesota: a few years ago the Minneapolis city council made an ordinance that allowed Muslim taxi drivers to refuse service, at their discretion, to anyone who has any alcoholic beverage (whether open or not) on their person or in their luggage. That's just one example of "stealth jihad" in America; there may be others, but I don't happen to remember the details at this time.  I should say, though, that "stealth jihad" is currently more of a problem in western Europe than in America. 24.23.197.43 (talk) 01:40, 11 April 2010 (UTC)
 * As far as saying goodbye, Nil Einne, I've made up my mind that I will never answer any question from you again, even if it's in my area of expertise (which is organic chemistry). So if you want advice on how to clean that crusted-over rice cooker, you better ask someone else. 24.23.197.43 (talk) 01:44, 11 April 2010 (UTC)


 * Not to further inflame this ("evil empire" was tongue-in-cheek, as, I hope, most here recognized), but the recent wars have not cost the US hundreds of billions of dollars, they have cost the US government (and, by logical extension, the US taxpayer) hundreds of billions of dollars. By far the largest part of that money flows back into the US economy, buying MRE's, Apaches, Hummers, ammunition, paying soldiers, shipping supplies, and maintaining the whole logistic train of a modern army. This is almost certainly more than 90% of the effort. And while every dead, US or Iraqi, is one to many, even the most conservative estimates show 10 times more Iraqis dying - and the peer-reviewed Lancet studies show two orders of magnitude between US and Iraqis bodycounts. There are some tough questions about morality here. --Stephan Schulz (talk) 09:07, 9 April 2010 (UTC)
 * Foreign policy is not about morality, and it's not supposed to be -- it's all about advancing the interests of the nation and its people, and if this happens at the expense of some other nation, so be it. Read our Constitution, for Pete's sake -- it clearly states that the government is responsible to the American people and nobody else, it says absolutely nothing about any other nation having any rights that we're required to respect. 24.23.197.43 (talk) 04:55, 10 April 2010 (UTC)
 * That's a stupid, inhuman, unenlightened and counterproductive position to take. Luckily, most Americans don't share it. It's also, of course, wrong. The US constitution does not mention responsibility at all. But one of the other, even more fundamental founding documents states "We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness." Emphasis added for your benefit.  --Stephan Schulz (talk) 10:01, 10 April 2010 (UTC)
 * Stephan Schulz, are you an American citizen? Because if not, then you have no say regarding American foreign policy and cannot speak for "most Americans" (oh, you have every 1st Amendment right to bitch about it all you want, but if you're not an American citizen, then nobody here cares what you think).  BTW, the Rassmussen polls (and a bunch of other polls too) indicate that the majority of American citizens favor putting their own country first in international matters. 24.23.197.43 (talk) 01:31, 11 April 2010 (UTC)

Early Earth
Suppose I had a time machine and went back 100 million years on some continent. If I brought a sturdy tent, camping tools, minimal food and water to last a month and a couple of rifles and shotguns, do you think I would survive a month? --Reticuli88 (talk) 14:37, 6 April 2010 (UTC)


 * That would put you in the age of dinosaurs. Back then, the air was breathable, although somewhat higher in oxygen, I think.  The water in rivers and lakes should also be drinkable.  Food might be a bit of an issue, as none of the food we've bred for our consumption yet existed, and I think that was even before flowering plants, which provide much of our current diet.  I suppose you could shoot small dinos for food, until you ran out of ammo.  You'd also need some type of shelter than would keep you safe while you slept.  A tent wouldn't do it.  If you could find an empty cave, then you'd only have to defend one side, and perhaps you could rig alarm bells to ring if anything entered.  Shotguns and rifles might not kill an attacking dino quickly enough, so something more like a bazooka might be in order.  Or, a flamethrower might work.  It wouldn't kill quickly, but might be weird enough that it would make a dino back off.  Also, to protect against ambush predators, you might want a mask with eyes on the back of your head.  This is a technique they use in India to protect against tiger attacks.  One other thing to worry about would be disease.  You would probably carry back many diseases that the dinos would have no defense against, so they would die off like flies.  They might also have some disease which no longer exists and which you have no defense against.  So, you'd probably want to wear a full anti-contamination isolation suit. StuRat (talk) 14:48, 6 April 2010 (UTC)


 * Just FYI, flowering plants have fossil evidence going back 140 million years. So they would exist, and if you brought back your own flowering plants (time travel paradoxes be damned) there would be pollinators available to keep them alive and reproducing (assuming the pollinators recognized them as potential targets for feeding; pollinators and flowers evolved hand in hand, so 100 million year old pollinators might not recognize your plants). As you noted, agricultural crops generally would not exist in a usable form, so you'd have to fall back on the hunter/gatherer diet of fruit, nuts and berries supplemented with meat from hunting. &mdash;ShadowRanger (talk 15:40, 6 April 2010 (UTC)


 * If you are stupid enough to carry several guns (how many to you plan shooting at any one time?) but no ammunition, probably not. Apart from that, possibly. 100 million years ago the atmosphere had about 30% oxygen - safe to breathe, but fire will be a much higher risk. CO2 was probably 3-10 times more prevalent than today, but still a factor of 10 below where you would expect direct physiological effects. Avoid T-Rex and don't catch a fungal infection, I'd suggest. --Stephan Schulz (talk) 14:57, 6 April 2010 (UTC)


 * Interesting Stephan...what would happen bullet-wise if you shot a gun in 30% oxygen/different oxygen setups? Would it catch fire/have adverse affects? any idea? In terms of 'food' if you killed a pig size animal you could theoretically live on its meat for quite a number of months, assuming you can cook and store it in a way that it won't go off and make you ill. 194.221.133.226 (talk) 15:33, 6 April 2010 (UTC)


 * Perhaps the lubricating oil on the gun might catch fire. As for storing food so it won't spoil, how would they do that ? StuRat (talk) 15:50, 6 April 2010 (UTC)


 * Salt. However, I think we're missing the point here. OP seems to be bringing "food and water to last a month" with him.Rimush (talk) 15:53, 6 April 2010 (UTC)


 * "her" --Reticuli88 (talk) 15:59, 6 April 2010 (UTC)


 * (ec)Or using a smoker. Beyond that, the original poster was only interested in living there for a month and returning, not living off the land. She could arrive with a few cases of granola bars, beef jerky and vitamin pills and bypass the need for food acquisition. I think she mostly wanted to know whether a well-equipped, well-prepared human could survive the hazards of the time without excessive measures like breather masks or environmental suits. &mdash;ShadowRanger (talk 15:56, 6 April 2010 (UTC)


 * They said "minimal food and water", so I took that to mean just enough for emergencies. Also, would they bring bags of salt with them, or mine them once there ? StuRat (talk) 15:57, 6 April 2010 (UTC)


 * Actually, they said "minimal food and water to last a month". I take that to mean "the minimum amount of food and water to last a month", since any other interpretation is too subjective to be useful. &mdash;ShadowRanger (talk 15:58, 6 April 2010 (UTC)

Great answers, thanks! I did mean to bring enough food to survive but if I wanted to snack more, I imagined I would be eating some exotic fruit or hunting small dino game. I guess the fruit would not be possible. Wouldn't there be other predators to be afraid of besides T-Rexes? Would there be any side effects of breathing 30% more oxygen? Would the sky look different to me? Would the moon look larger? Would I smell the difference in the atmosphere? --Reticuli88 (talk) 16:07, 6 April 2010 (UTC)


 * A similar question was discussed before here . I think you'd absolutely want to bring some good vitamin suppliments along.  Who knows what important nutrients are missing in dinosaur meat.APL (talk) 16:30, 6 April 2010 (UTC)


 * As I noted earlier, fruit might exist (flowering plants and fruit frequently occur hand in hand). Of course, you'd have to figure out if it was poisonous or not. There would be numerous predators to deal with, though technically, no T-Rexes (they existed only for a few million years immediately preceding the extinction, not 100 million years ago). You'd probably be a bit light headed for a little while on arrival, but the increased oxygen is within human adaptive tolerances (oxygen toxicity of any sort doesn't seem to kick in until the atmosphere is 50% oxygen, and I believe it tops out around 30% historically). You wouldn't "smell" the difference in the atmospheric composition as far as the excess oxygen goes, though obviously smells produced by now extinct flora and fauna would likely be different. The increase oxygenation would speed decomposition too, so rotting material would smell more intensely, but stick around for shorter periods. Can't say what the sky or Moon would look like; technically, I believe the Moon was a little closer, but I doubt it would be particularly noticeable. &mdash;ShadowRanger (talk 16:23, 6 April 2010 (UTC)


 * Just a note; many modern "dangerous" animals are more scared of humans (and consequently more dangerous) due to evolutionary pressures (to wit; we killed and ate the ones that weren't afraid of us). While there were more predators in the period described, you'd probably be safe around the herbivores; they wouldn't know enough to consider you a threat. The predators might be a problem, but they wouldn't have any particular experience or instinct for dealing with humans; simple traps and your weapons would likely encourage them to seek easier prey. &mdash;ShadowRanger (talk 16:28, 6 April 2010 (UTC)


 * I would think you might tend to hyperventilate, when you exerted yourself, in an atmosphere with more oxygen and carbon dioxide. There were lots of other predators, like velociraptors, although those didn't actually appear until 75 million years ago.  Actually, even if it was around, a T-Rex might ignore you, if something bigger was on the menu.  BTW, the giant insects might be an annoyance.  The days would also be noticeably shorter.   StuRat (talk) 16:33, 6 April 2010 (UTC)
 * Velociraptors, were the size of a modern day chicken - really not that much to worry about! (That goddamn Jurassic Park movie has a lot to answer for!)  It seems possible that T-Rex was only a scavenger - although this is a controversial view - maybe not too much to be concerned about? SteveBaker (talk) 03:11, 7 April 2010 (UTC)


 * Don't forget to bring a supply of antibiotic pills, and you might as well start taking them immediately; there are presumably trillions of nasty germs that'll land on you from which you have no immunity, because they've died out by 2010. I don't have it at hand, but GURPS Time Travel is an RPG sourcebook that has lots of good information like this for the practical time traveler.  One sidebar helpfully tells the reader:  Stop reading the rest of this book for a minute, and memorize this formula, just in case you are sent way back in time at some point in your life:  75% saltpeter, 15% charcoal, and 10% sulfur.  Comet Tuttle (talk) 18:17, 6 April 2010 (UTC)
 * So, where do you find saltpeter? Memorizing the formula is only useful if you're in a well-labeled chemical supply closet.  You need to be able to locate and identify natural sources, understand how to process them, and have enough general understanding to improvise substitutes if necessary.  Nothing short of a solid understanding of chemistry and physics is sufficient to really re-manufacture modern conveniences - there's not simply "one formula to memorize".  Nimur (talk) 21:15, 6 April 2010 (UTC)


 * Nimur, I can see you are not exhibiting that "can-do" attitude that will allow you to adequately exploit your futuristic knowledge when you get catapulted back a thousand years. See Lord Kalvan of Otherwhen &mdash; and, in fact, the main character is a (part-time, I think) reference librarian, just like you and me.  Here's one link about naturally occurring saltpeter and speculation on how it was processed, and the quality of early black powder.  Comet Tuttle (talk) 23:01, 6 April 2010 (UTC)


 * Another good book to read, of course, is The Mysterious Island by Jules Verne. In it you can learn such useful skills as smelting iron from ore and making nitroglycerin from seal blubber, even if you're stranded on a strange island with nothing but the remains of a hot-air balloon and the glass face of a watch. Of course, you may have to adapt the nitroglycerin recipe; I don't think you're too likely to find seals 100 million years ago. —Bkell (talk) 02:54, 7 April 2010 (UTC)


 * A good precaution, but I'm not sure how problematic it would be in practice. The mammals of the time are so different from modern day humans that it would be a fairly uncommon disease that would pose a risk to you, and saurian diseases that can affect mammals are even less common. Granted, if you stay there too long, the germs you carry with you might have time to exchange genes with the local germs and "teach" the local germs how to interact with your biology, but I would think the biggest threats would be from pathogens that don't rely on adaptations to individual species' biology. For example, virtually no virus, and only extremely rare bacteria and monocellular parasites would pose a threat. Fungi and multicellular parasites would be much more likely to cause problems. &mdash;ShadowRanger (talk 18:26, 6 April 2010 (UTC)


 * Just as an aside, it is possible to survive almost anywhere for a month, if you import enough provisions. Antarctica, the middle of the ocean, outer space...  the real question is whether one would be able to survive for an indeterminate period of time (a condition which would force one to integrate oneself into the environment).  that's a much more difficult task to accomplish.  -- Ludwigs 2  18:52, 6 April 2010 (UTC)

Stu you wouldn't need a shoulder launcher missile weapon to deal with dinosaurs that could fit inside a cave. I think an M14 rifle would be of sufficient calibre to deal with them. For handling the larger dinosaurs you can use an RPO. A flamethrower would require insanely close range and run through ammunition ridiculously fast. An M107CQ carbine firing .50 BMG would be anotehr excellent weapon to bring with you if you could. So those three weapons in that order of preference would be my choice. Rather than sleeping in a cave, as caves are hard to find are chock full of poisonous spiders and snakes, I think a lined hole in the ground with overhead cover would be preferable.--92.251.159.250 (talk) 23:03, 6 April 2010 (UTC)


 * The flamethrower would also be useful for swarms of small predators. Most predators would back off with one blast from it, you wouldn't need to actually hit them.  They would think: "that thing is dangerous, I'm outta here". StuRat (talk) 01:34, 7 April 2010 (UTC)


 * An Abrams tank might be useful. It could tow the trailer with fuel and supplies. I expect T-Rex tastes a bit like chicken. Edison (talk) 23:21, 6 April 2010 (UTC)


 * Meh if you want to use something like that use an M1128 MGS. It's basically an APC with a tank gun on top, and 3 machine guns of various calibres attached to different spots. You could sleep inside and also carry provisions in the vehicle itself so you wouldn't have to risk yourself outside. I don't think we're allowed to bring vehicles however.--92.251.159.250 (talk) 23:36, 6 April 2010 (UTC)

As to the Moon, see Orbit of the Moon and Tidal acceleration. The Moon is currently receding by 38 mm/year, but the average rate over the last 620,000,000 years was only about 22 mm/year. So in the last 100,000,000 years it must have receded by somewhere between 2,200 and 3,800 km. It would look maybe 1% larger: as stated above, not enough to notice. The day would also be about 20 minutes shorter than now.

On the other hand, the proper motion of many of the stars over 100,000,000 years would be plenty noticeable. If you know what the constellations look like today, and had an opportunity to see the night sky without being eaten first, you would find the differences obvious; I suspect you would not find any recognizable constellations at all. And even if you did, you would also find the axis of the Earth pointing in a different direction due to axial precession (well, probably different; it might have rotated by an integer number of times and returned to the same place, just by chance). So if there was a pole star like Polaris today, it would be a different star for that reason. --Anonymous, 23:34 UTC, April 6, 2010.


 * If you were on the Earth either 100 million years ago or 100 thousand years ago, if you were in an area teaming with a lot of life, I think your senses would be bombarded with stimulation more so than most people generally experience today. Smells, sights and sounds would be a presence that we would only experience today if we planted ourselves amidst some large and largely undisturbed-by-mankind plot on the planet. Human activity, I think, has suppressed the imposition that all other forms of life would have on us. Bus stop (talk) 03:03, 7 April 2010 (UTC)


 * I think the biggest problem is likely to be food (unless you bring enough with you). We have no clue whether dinosaur meat would be edible - after all, there are plenty of reptiles with poisonous flesh.  I'd want to try to find a crocodilian of some kind to hunt - although 100 million years ago is a bit far back and you'd be looking for proto-crocodilians (Crurotarsi).  But those creatures appear to have changed relatively little over the intervening time - and since we know that Alligator meat is very edible (rather delicious, actually), that would be your best bet.  You might also want to hunt and eat mammals of that period - again, on the grounds that there are few (if any?) present day mammals with poisonous flesh.  Fruit and veg would be available - but again, how do you know what you can and can't eat?  Roots and nuts have similar problems.  You could certainly start taking chances on strange foods if you got desperate - but it's a hard risk to assess.  Hiding out from large carnivores might not be so hard - the ratio of carnivores to herbivores tends to be fairly constant over time - and you can certainly live for a long time in the wilds of modern day Earth without having problems with them.  I also suspect that you'd have little problem with bacterial/viral diseases.  Most diseases don't cross species very well - and nothing back then is evolved to infect humans.  Fungal problems might be a bigger issue - but if you can keep your feet dry and body clean - and take care to dress open wounds properly - you ought to be able to fend off that kind of attack for a month.  Water is just water - I don't see any special problems there either.  Overall, I think that anyone who could survive a month somewhere out in the wilds  of modern earth would have little additional problems 100 million years ago.  Just don't lose the spare batteries for your time machine...that might be bad! SteveBaker (talk) 03:07, 7 April 2010 (UTC)


 * If you were forced to try the local foods, I'd recommend some sort of methodical poison tests like described in this article . (And its references.).  It's far from a sure thing, but it would at least lessen the risks. APL (talk) 04:39, 7 April 2010 (UTC)


 * @Steve Baker - okay, so there are reptiles with poisonous flesh. But you're talking about dinosaurs. Are there any poisonous birds? --Polysylabic Pseudonym (talk) 08:36, 7 April 2010 (UTC)
 * Hooded Pitohui. --Sean 15:20, 7 April 2010 (UTC)
 * Dinosaurs are not birds. A small sub-group of them evolved into modern birds. But a lot of them were much more like modern reptiles than modern birds. APL (talk) 16:17, 7 April 2010 (UTC)
 * But they are all genetically closer to us than all current birds or reptiles. I think the chances are very good that nearly all dino-meat is going to be edible, just as nearly all bird-meat is. --Stephan Schulz (talk) 16:21, 7 April 2010 (UTC)
 * The seeds of the ginkgo biloba are edible, but bitter-tasting. ~ A H  1 (TCU) 03:41, 10 April 2010 (UTC)

Poles on a DC Motor
There seems to be many different types of DC Motors. Each has a different way/pattern to how the external poles are arranged. As the DC Motor ages the markings tend to disappear as does the manufacturers data plate. This condition leaves a DC motor without markings or data plate from which to identify the DC Motor. I have a very old possibly 1971 DC Motor in a old golf cart now used for pleasure as a Low-Speed_Vehicle(LSV)licensed for the streets. The wiring is in question and I want to know how I can know with certainty which DC Motor pole is used for what? How can I check the motor to make certain it is good? Thank You Norman pickett (talk) 15:22, 6 April 2010 (UTC)


 * Well, the obvious answer is to hook the positive and negative leads up one way, see if it works, and, if not, try the other way. Some motors will go backwards when hooked up at the reverse polarity.  Others will do nothing.  Are you afraid that hooking it up backwards could damage it ? StuRat (talk) 15:54, 6 April 2010 (UTC)
 * The plate on the motor may be illegible, but have you tried Googling on all the information you have on the cart (like make, model, chassis number etc.) There are a lot of  cart fanatics out there with wiring diagrams. There are also a lot of amps that can melt things if you get it wrong.  A meter should be able to identify which field winding is which. The poles to the commutator would (I imagine) cause the meter to  flicker unsteadily as you turned the rotor by hand.  The good thing is that at a 1970s machine  is unlikely to have any fancy electronic control circuits. On the bad side: it is sacrilege to use a golf cart for anything but the proper purpose and you may find a thunderbolt strikes you down the first time you take it out for a spin.--Aspro (talk) 16:50, 6 April 2010 (UTC)

Flaming globes of Sigmund - dreaming phenomenon
Often, a person awakening from a dream retains the memory of a striking sentence or phrase which impressed the dreamer as funny, profound, or otherwise significant. However, on later inspection, the phrase proves meaningless or absurd. The phenomenon is illustrated in the Seinfeld episode "The Heart Attack", in which Jerry awakens chuckling, scribbles "flaming globes of Sigmund" on a scrap of paper, and goes back to sleep convinced that he has composed a joke. In Jerry's case, he cannot remember the actual meaning of his scribblings the next day, though he retains a vague sense that they were important. In my case, I often awaken with a memory of specific words, which seem, in the immediate aftermath of awakening, to retain their meaning, only to lose it gradually as the morning wears on. The words remain, but the sense of meaning dissolves. Is there a scientific term for this kind of phenomenon? How prevalent is it? Has it been the subject of any notable research? L ANTZY T ALK 16:40, 6 April 2010 (UTC)


 * I attribute that to us thinking something is profound in a dream state, but, once we regain our ability to think logically, we know it's just gibberish. Something similar happens to people on some drugs and alcohol:  They think they are having profound thoughts, but, if they record them, they later realize they were total crap, once they sober up. StuRat (talk) 16:58, 6 April 2010 (UTC)
 * You may find a couple of our articles helpful. Take a look at Oneirology and Dream. 10draftsdeep (talk) 18:33, 6 April 2010 (UTC)


 * The term I've seen used is "dream amnesia" -- things that happen in dreams make it into short term memory but aren't consolidated into long term memory unless they receive attention shortly after awakening. The sense of familiarity is probably related to the tip of the tongue effect, and perhaps to Déjà vu. Looie496 (talk) 23:48, 6 April 2010 (UTC)


 * The article Psychedelic experience sheds some light on perceived importance in dreams, e.g. "Level 2" where "Vast increase in abstract thought becomes apparent as the natural brain filter is bypassed". Cuddlyable3 (talk) 18:30, 9 April 2010 (UTC)

Thymus vulgaris
Is Thymus vulgaris an annual? Googlemeister (talk) 18:30, 6 April 2010 (UTC)


 * This site says it's an evergreen. I've never been able to grow it more than about 2 years though. By the way, the picture in our article looks more like Rosemary (Rosmarinus officinalis) to me. --TammyMoet (talk) 18:42, 6 April 2010 (UTC)


 * I would call it (or WP calls it ) a Subshrub; err... so No I don't think so as it survives the winter. --Aspro (talk) 18:44, 6 April 2010 (UTC)
 * Did you read the article you linked to? It seems to contradict you - the second paragraph says the woody stem overwinters. --Tango (talk) 01:32, 7 April 2010 (UTC)


 * This site calls it a perennial: . StuRat (talk) 18:47, 6 April 2010 (UTC)
 * Yes it grows for many years and can layer new roots with new growth resulting. Graeme Bartlett (talk) 08:46, 7 April 2010 (UTC)

Another factoid for discussion...
'Whenever it has been established that a bird possesses the ability to count, it can usually only count up to as far as the number of eggs typically laid by its species per clutch, plus one'. I suppose that the wisdom behind this being that the only real use a bird has for counting objects is to determine if am egg has been taken or if nest parasite or another member of its species has laid an extra egg in its nest. Confirm/debunk? I'm trying to tie this in to something my grandmother once told me about a chicken's ability to count as related to the number of 'foreign' (i.e. from another hen, or a duck - as is/was done 'down on the farm') eggs that can safely be placed in with her clutch without her freaking out. It was something along the lines of 'she only counts the first seven, so if she already has seven eggs, you can add more and she won't notice - but if she has six and you add a seventh, she'll abandon the whole lot or start destroying eggs' - but I may be remembering that wrong (long time ago now). --Kurt Shaped Box (talk) 18:48, 6 April 2010 (UTC)


 * Our article Bird intelligence claims some birds have been shown to be able to count up to 3, 6, or possibly 8. It warns birds may be subitizing and not truly counting. Comet Tuttle (talk) 19:31, 6 April 2010 (UTC)


 * This statement sounds a lot like the premise behind rabbit math in the novel Watership Down. The main character's name is "Hrairoo", which is translated into English as "Fiver"; he was some number past 4 in his litter, and rabbits can only count up to 4; all numbers past that are "Hrair", which means "more than 4".  -- Jayron  32  20:20, 6 April 2010 (UTC)


 * I'd say that most birds also cannot recognize the eggs of other species of birds from their own. See brood parasite. ~ A H  1 (TCU) 03:38, 10 April 2010 (UTC)

what am I doing wrong with this acid base problem? (sodium acetate solution
> acidic pH?) ==

I have NO idea why I'm getting an acidic pH. I have pure sodium acetate solution and there is no external source of H+ except for water.

Firstly, this is being conducted at 80 C, so K_w is modified to 1.5 * 10^-13. Which shouldn't be too much of a hiccup.

[H+] = 1.5 * 10^-13 / [OH-]

Relying on the approximation, [OH-] = [AcOH].

so K@353K = 8 * 10^-5 = [AcO-][H+] / [AcOH] = (0.1-x) * (1.5 * 10^-13 / [x]) / (x) = (1.5 * 10^-14 - (1.5/x) * 10^-13) / x = 1.5x^-1 * 10^-14 – 1.5x^-2 * 10^-13 = 8 * 10^-5 0 = 8x^2 * 10^-5  - 1.5x * 10^-14  + 1.5 * 10^-13 0 = 5.33x^2 * 10^8 – 0.1x + 1 5.33x^2 * 10^8 = 0.1x – 1 (the last term is negligible) 5.33 * 10^8 x = 0.1 0.1 / (5.33 * 10^8) = x = 1.876 * 10^-10  = [OH-] pOH = 9.7267 pH = 12.824 – pOH = 3.097

The 353K water makes it slightly more acidic, but I should still get an alkaline solution, right?

John Riemann Soong (talk) 21:53, 6 April 2010 (UTC)


 * It would help if you annotated your equations. I'm not sure exactly (it's been a while since I did this) but your issue might be that you set up the equation wrong initially. The sodium(Na+) and the acetate (AcO-) presumably dissociate completely leaving whatever your molar concentration is of acetate in solution. The acetate, being a weak acid, starts grubbing for protons from the water and establishes an equilibrium between acetate (AcO-) and acetic acid (AcOH) and OH-. I think your equation should be set up with AcOH and OH- on the top and AcO- and H2O on the bottom. The pKb of acetate from sodium acetate is 9.25 btw. Hope someone will correct me if I am wrong... 152.16.15.144 (talk) 22:30, 6 April 2010 (UTC)


 * Well I kind of solved it a different way. (As in I found a correct answer another way.) But I'm using K_a, so I just modified the expression to use K_a. I defined H+ in terms OH-, and worked from there... I wonder why it doesn't work ... John Riemann Soong (talk) 23:46, 6 April 2010 (UTC)

do the effects of smoking ever go away? (smoking regular cigarettes like marlboros)
1. do the effects of smoking ever go away? specifically, you see pictures of healthy nonsmoker's as contrasted with all charred up smoker's lungs; if somebody stops smoking (say, after 5-6 years of smoking from 19-25), then presumably their lungs are between the two. Would they get back to totally healthy after a number of years? Or would the blackened tar and stuff stay in their lungs for the rest of their lives? 2. besides the black tar, what other symptoms do smokers develop that might stay with them? (e.g. yellow teeth, wrinkles, and so on) 3. how much of specifically the lung effect is present for a second hand smoker? would this disappear after a number of years? For someone who is not a smoker, but around smokers when they smoke, would the same lung effect be present? Would this disapear after a number of years if they were exclusively in nonsmoker areas? Thank you very much. Note: I am not asking for medical advice. 82.113.106.35 (talk) 21:53, 6 April 2010 (UTC)


 * This site should help with your first question. I think passive smoking has the same effects as direct smoking, just reduced. How severe those effects will be will, of course, depend on the level of exposure. --Tango (talk) 22:04, 6 April 2010 (UTC)
 * I cannot speak about the effects to one's lungs, but studies show that the effects to one's periodontium (in terms of how smoking effects wound healing, etc. in periodontal disease, implant placement) take 11 years to become statistically insignificant.  DRosenbach  ( Talk 03:53, 7 April 2010 (UTC)


 * The Surgeon General's report answers a couple of your questions. After about three years, the risk of heart attack falls to that of a never-smoker. It takes over 15 years of cessation for the risk of lung cancer death to fall to that of never-smokers. Axl  ¤  [Talk]  07:50, 8 April 2010 (UTC)

ex=paratrooper with back problem been put on tramadol for 8 years.........

 * I'm sorry, but this appears to be a request for medical advice, which we cannot legally provide. Please ask your doctor for more information. &mdash;ShadowRanger (talk 22:09, 6 April 2010 (UTC)


 * Actually, the concern is not that we "cannot legally provide" it; it is an ethical concern &mdash; what if we, anonymous people on the Internet, give you advice which you follow, and we're wrong, and your partner ends up screwing up his health more? You do need to consult a doctor about any medical advice, sorry.  Comet Tuttle (talk) 22:48, 6 April 2010 (UTC)


 * D'oh. Mixed up medical and legal advice. Though I suppose in both cases it's primarily a matter of ethics. Thanks for the reminder. &mdash;ShadowRanger (talk 15:58, 7 April 2010 (UTC)

Sodium bicarbonate
Is sodium from sodium bicarbonate (baking soda) as unhealthy as sodium from sodium chloride (salt)? --70.129.184.122 (talk) 22:12, 6 April 2010 (UTC)


 * Yes, insofar as when it reacts in your stomach, it produces NaCl, per this reaction diagram from the article:
 * NaHCO3 + HCl → NaCl + H2CO3
 * H2CO3 → H2O + CO2(g)


 * The amount of sodium per gram will be less than the amount per gram of NaCl though. &mdash;ShadowRanger (talk 22:15, 6 April 2010 (UTC)


 * Really, the Chloride doesn't matter at all: it's the Na+ ion that's bad for you, and the chloride's just along for the ride. Of course, baking soda does contain less sodium per mass (39% for salt vs. 27% for baking soda), and  most people consume a lot less baking soda than they do salt. Buddy431 (talk) 00:00, 7 April 2010 (UTC)


 * However, eating elemental metallic sodium would be a very bad idea. StuRat (talk)


 * OUCH!!! 24.23.197.43 (talk) 01:28, 7 April 2010 (UTC)


 * Acid + metal reaction...very bad idea. ~ A H  1 (TCU) 02:59, 7 April 2010 (UTC)


 * Yeah, I was pretty sure it wouldn't matter, but I figured illustrating that sodium bicarbonate becomes sodium chloride in your stomach would illustrate why. In other circumstances, ingestion of a particular element won't lead to digestion and absorption if the element in question is tightly bonded or otherwise indigestible (e.g. insoluble fiber contributes nothing to your nutritional needs, it just aids movement within the digestive system). Since sodium bicarbonate has a known reaction with your stomach's hydrochloric acid, and the result is salt, there is no doubt that it will be treated identically. &mdash;ShadowRanger (talk 15:50, 7 April 2010 (UTC)


 * Using yeast instead is not difficult, at least in a bread-machine. I sometimes add sultanas to the flour to get something cake-like. People must have made cakes with yeast before baking powder was invented. 78.149.173.243 (talk) 10:39, 7 April 2010 (UTC)


 * You still get sodium ions when you consume any soluble sodium salt. Sodium ions have the certain health effects (they are not necessarily bad, by the way), regardless of the anion, even though the anion may mitigate or augment the effects.--Cheminterest (talk) 20:37, 7 April 2010 (UTC)


 * Sodium ions per se are not harmful to human health -- indeed, they are essential for human cells to function properly. It's only when you consume too much sodium, or too much at one time, that it can become a health problem.  24.23.197.43 (talk) 05:55, 8 April 2010 (UTC)

Time and the Big Bang
Which frame of reference was chosen so that our recent estimations were considered? For instance, it took about less than 400,000 years for the decoupling event to have occurred after the Big Bang and the estimated age of the Universe is 13.75 billion years.--Email4mobile (talk) 22:32, 6 April 2010 (UTC)


 * I'm not sure what you're asking but it seems to me that the right answer to your question likely is the comoving frame with the galaxies. Read comoving coordinates. Dauto (talk) 02:28, 7 April 2010 (UTC)
 * Can I translate the phrase "comoving" as "Associated with movement"?--Email4mobile (talk) 12:19, 7 April 2010 (UTC)
 * It is, but that would not be helpful in the least. Click the link and read what it means. &mdash;ShadowRanger (talk 12:41, 7 April 2010 (UTC)
 * Yes, ShadowRanger, but I would like to translate this article into Arabic wiki. In this case I've to to give it a meaningful name.--Email4mobile (talk) 16:05, 7 April 2010 (UTC)
 * Ouch. Defining it without resorting to incredibly drawn out language seems tricky. I have no idea what Arabic speaking scientists would use to describe it; the problem is that any attempt to translate it directly will likely lack scientific precision. I suppose for lack of another option, you might try creating an article on the closest translation for "comoving frame" you can come up with and link it from your Arabic wikipedia article (and make it clear what the English equivalent is). If a bilingual English/Arabic speaking scientist can provide the proper terminology, the article could be renamed and the terminology corrected for scientific accuracy. Sorry I can't help more; my knowledge of Arabic comes from the few untranslated words in my hundred year old copy of the Thousand Nights and One Night (as it is titled for my edition), plus the overlap of my abysmal knowledge of Hebrew (a dozen words or so) with Arabic cognates (leaving only two Arabic words). &mdash;ShadowRanger (talk 16:21, 7 April 2010 (UTC)
 * lol, Shukran (means Thanks), ShadowRanger. Unfortunately, there is no Arabic wiki article containing the term comove yet but I will go ahead with the translation anyway. Someday an Arab scientist will give it the correct name. Have a nice time with Alf Laila wa Laila (Thousand Nights and One Night). --Email4mobile (talk) 16:51, 7 April 2010 (UTC)
 * In case it helps, "comoving" has the sense of "moving along with" something else, which I think is a little more specific than "associated with movement." You can think of a twig or leaf moving along with the water in a river.  -- Coneslayer (talk) 16:57, 7 April 2010 (UTC)
 * Yes, it really isn't a complicated idea. The times (like 400,000 years) are measured by clocks that are moving with roughly the same speed as the stuff around them. These days you have to average over a pretty large area (tens or hundreds of millions of light years) to get rid of local variations in speed. The early universe was much more uniform, though, as well as much denser, and you would immediately encounter a lot of resistance if you didn't "go with the flow". An easier way to figure out the right speed in the present-day universe is to look at the cosmic microwave background, which is still very uniform (because light doesn't clump together the way atoms do). If the microwave background looks blueshifted in one direction and redshifted in the opposite direction, then you're going too fast in the blueshifted direction. -- BenRG (talk) 19:12, 7 April 2010 (UTC)
 * If you ever need a dozen hundred year old Arabic slang words for genitalia, I'm your man. The translators of my edition were quite prudish. :-) &mdash;ShadowRanger (talk 18:44, 7 April 2010 (UTC)
 * Yes, Coneslayer. I went through the article and then understood it can be an alternative to "get/go along with" which has an equivalent single-word in Arabic. Thanks for all of you.--Email4mobile (talk) 18:09, 7 April 2010 (UTC)

discrepancies in attempting to isolate enthalpies/entropies of dissociation
At 293K, I am told the K_a for formic acid is 1.765 * 10^-4, but 1.768 * 10^-4 at 303K.

Using the simultaneous equations: ∆H – 293K*∆S = ∆G @ 293K = -R * 293K ln (1.765 * 10^-4)  (21054 J/mol) ∆H – 303K*∆S = ∆G @ 303K = -R * 303K ln (1.768 * 10^-4)  (21768 J/mol)

21054 J/mol – 21768 J/mol = -714 J/mol = (293-303)K * ∆S (714 J/mol / 10K) = 71.43 J/(mol*K) = ∆S

but, plugging back in: 21054 J/mol + 293K*71.43 (J/(mol*K)) = 41974 J/mol = ∆H and I get delta-H of 43400 J/mol at 303K. Uhhhh? John Riemann Soong (talk) 23:03, 6 April 2010 (UTC)


 * Try this instead. I am not sure what you did wrong, but if you reduce the simultaneous equations to a single equation, you should get


 * ∆G1 - ∆G2 = (T2 - T1)∆S, or simpler
 * ∆G293 - ∆G303 = (303-293)∆S or even simpler
 * ∆G293 - ∆G303 = 10*∆S


 * I get ∆G303 = 21756 J/mol, and ∆G293 = 21042. Sub those in, and I get


 * 21042 - 21756 = 10*∆S
 * -714 = 10*∆S
 * -71.4 J/molK = ∆S
 * Back to your initial two equations now,


 * ∆G293 = ∆H - 293*∆S
 * 21042 = ∆H - 293*(-71.4)
 * 21042 = ∆H - (-20920)
 * 122 J/mol = ∆H
 * and for the other temperature


 * ∆G303 = ∆H - 303*∆S
 * 21756 = ∆H - 303*(-71.4)
 * 21756 = ∆H - (-21634)
 * 122 J/mol = ∆H
 * Same answer. Near as I can tell, you dropped a - sign in your final step, so you added where you should have subtracted.  BTW, I charge $40.00 per hour for this sort of tutoring, so this coupled with the amine-buffer help below would normally cost you some serious coin... -- Jayron  32  04:26, 7 April 2010 (UTC)

Health hazards from living near a busy road
Is there any information available about how dangerous it is to live x metres from a busy road, in terms of reduced longevity and so on? I'm thinking of the traffic fume pollution, such as the particulates and Polycyclic aromatic hydrocarbons, and how these may decline (or not) with distance from the traffic. Thanks. 92.29.111.79 (talk) 23:17, 6 April 2010 (UTC)


 * There are also claims that long term exposure to the noise of a busy road can have a deleterious effect. --Tango (talk) 23:21, 6 April 2010 (UTC)


 * A quick googl search (living near an road health) netted me these, among others:, , , etc. I'd say yes, there is information available, though I'm not sure you'll find a direct x meters to nearest road vs. mean lifespan graph anywhere. Buddy431 (talk) 00:54, 7 April 2010 (UTC)


 * There's also the possibility of being hit by a car, the stress caused by having cars whip by, and, if the road has been there a long time, an accumulation of lead and toxins in the soil near the road, which is a problem if food is grown there. StuRat (talk) 00:59, 7 April 2010 (UTC)


 * See also noise pollution. ~ A H  1 (TCU) 02:52, 7 April 2010 (UTC)

Try this article. It has quite detailed information, and is not entirely intuitive. If you would like my interpretation of it, please ask. Axl ¤  [Talk]  22:05, 7 April 2010 (UTC)
 * Thanks. "For an increase in traffic intensity of 10,000 motor vehicles in 24 hours (motor vehicles/day) on the road nearest a subject's residence, the RR was 1.03 (95% CI, 1.00-1.08) for natural-cause mortality, 1.05 (0.99-1.12) for cardiovascular mortality, 1.10 (0.95-1.26) for respiratory mortality, 1.07 (0.96-1.19) for lung cancer mortality, and 1.00 (0.94-1.06) for noncardiopulmonary, non-lung cancer mortality. " Does the RR of 1.03 mean a 3% increase in mortality? Is it possible to esimate the reduced average longevitry please? 92.29.42.231 (talk) 10:15, 8 April 2010 (UTC)

" Does the RR of 1.03 mean a 3% increase in mortality? "


 * Yes.

" Is it possible to estimate the reduced average longevity please? "


 * There is a rather complex relationship between mortality rate and life expectancy. This website gives a nice summary. The article doesn't give enough infomation to calculate life expectancy. It took me quite a bit of digging around to find an estimate for life expectancy. This report from the Committee on the Medical Effects of Air Pollution, page 6, states "Estimate of effect in time-series studies based on a 1 microg/m3 reduction in annual mean PM10 assuming a coefficient of 0.075%, a loss of life expectancy of 2 to 6 months per death brought forward and a similar effect on all ages."


 * Axl ¤  [Talk]  09:41, 10 April 2010 (UTC)

calculating the %protonation of amine in an ammonium acetate like salt...
I have 0.32M formic acid solution (K_a = 1.765 * 10^-4). I then add 0.2 equivalents sodium hydroxide. I then add 0.32M of an amine (K_b = 8 * 10^-3).

How do I calculate the %protonation of the amine?

My current work: The 0.32M formic acid solution + 0.2 equiv NaOH is calculated to have pH 3.3156. A- / AH = 0.2529; e.g. there is 0.06459 M formate anions and 0.2554 M formic acid.

Ka for formic acid = [H+][HCOO-] / [HCOOH]

Kb for amine = [OH-][RNH3+] / [RNH2]

Ka_acid * Kb_amine = Kw [HCOO-][RNH3+] / [RNH2][HCOOH]

Now I'm stuck. John Riemann Soong (talk) 23:44, 6 April 2010 (UTC)


 * Back up a bit. The formic acid/NaOH is just a buffer; I assume you used the Henderson-Hasselbalch equation to calculate the pH.  At that pH, pOH = 14-3.3156 = 10.6048, so [OH-] = 10^-pOH = 2.48 * 10^-11.


 * Now, use the equation Kb = [RNH3+]*[OH-]/[RNH2], and subbing from the bottom line of the above table, you get 8 * 10^-3 = (x)*(2.48 * 10^-11 + x)/(0.32 - x). Solve for x. Plug the x value back into the bottom line of the above table to find the equilbrium concentrations of [RNH2] and [RNH3+], and % protonation is simply ratio of the equilibrium concentrations * 100, or [RNH3+]/[RNH2] * 100.  I hope that made sense.  This is much easier to teach when talking to someone in person... -- Jayron  32  03:57, 7 April 2010 (UTC)