Wikipedia:Reference desk/Archives/Science/2008 October 19

= October 19 =

nigilism
a foreign friend referred in passing to 'nigilism' - what could she have meant? —Preceding unsigned comment added by 79.122.55.76 (talk) 00:45, 19 October 2008 (UTC)
 * or niginism or something similar. I first thought she was trying to say "nihilism" but no...  —Preceding unsigned comment added by 79.122.55.76 (talk) 00:47, 19 October 2008 (UTC)
 * COuld you provide more context to the conversation? If we knew what she or you were discussing at the time, it might help figure out what she was trying to say... --Jayron32. talk . contribs 00:54, 19 October 2008 (UTC)
 * Google book search for "nigilism" produced 25 hits:. Seems to come from Russian literature, in the character of Bazarof introduced in 1861 by Turgenief. Too turgid for me to follow: . Some of the hits are bad optical character reading of "nihilism" and it seems to be nothing more than a quirky Russian spelling of same, per, which says nigilism=nihilism " g in Russian doing service for h."  Edison (talk) 01:07, 19 October 2008 (UTC)
 * I think you're right on. In Russian Cyrillic the concept is spelled "Нигилизм" which can be romanized to "Nigilizm" 02:40, 19 October 2008 (UTC)
 * Weren't inhabitants of parts of the Soviet Union in WW2 under the impression that they were being persecuted and killed by "Gitler?" See "Re: Gooray for Gollywood". AGoogle search shows that a number of persons apparently from non-English speaking backgrounds spell the name in English "Adolf Gitler."Edison (talk) 04:08, 19 October 2008 (UTC)


 * 'h' in loanwords often becomes 'g' in Russian; I guess this is because some other Slavic languages regularly have /h/ where Russian has /g/ – see e.g. Ukrainian city-names with –hrad vs Russian –grad. —Tamfang (talk) 20:39, 19 October 2008 (UTC)


 * My brain is niggling at me, and has asked me to mention that it's surprised the Russians didn't have a word such as ничевизм (nichevizm), from ничего (pron. nichevó, meaning "nothing"). --  JackofOz (talk) 07:03, 20 October 2008 (UTC)
 * Do give my regards to your brain. —Tamfang (talk) 05:17, 25 August 2023 (UTC)
 * Just as another example, there's Ibraham Petrovich Gannibal, the "black slave" of Peter the Great. Gannibal/Hannibal was an ancestor of Pushkin. - Nunh-huh 07:44, 20 October 2008 (UTC)
 * I suppose this should more likely be at the Linguistics desk...but anyway, as noted, Russian has no letter directly corresponding to our H. Although it's typically Г (for example, О. Генри, the writer O. Henry), it's occasionally something else: for example, hobbit becomes Хоббит.  Nyttend (talk) 17:15, 22 October 2008 (UTC)

Skin condition photos
I added some old photos to Erythema multiforme. However, this photo shows what is meant by Erythema multiforme target lesion, and the target lesion do not appear to be in either photo set in the Erythema multiforme article. If you have a chance, would you take a stab at identifying the skin conditions in the photos in the Erythema multiforme article so that the photos can be placed in the correct skin condition article. Thanks. -- Suntag  ☼  01:37, 19 October 2008 (UTC)
 * This seems closer for the first set having three photos. -- Suntag  ☼  01:56, 19 October 2008 (UTC)

Dream On! Dream On! Dream until your dreams come ... on a small video monitor?

 * http://www.telegraph.co.uk/earth/main.jhtml?view=DETAILS&grid=&xml=/earth/2008/10/17/scidream117.xml
 * Black and white TV generation have monochrome dreams
 * By Richard Alleyne, Science Correspondent
 * Last Updated: 5:01pm BST 17/10/2008


 * While almost all under 25s dream in colour, thousands of over 55s, all of whom were brought up with black and white sets, often dream in monchrome - even now. ...

This is funny, however, ...


 * why wouldn't people have commercials inserted in their dreams?
 * why don't people dream in flat-colored pencil outlines thanks to all the animations they have seen during childhood?
 * why don't people have silent movie dreams, i.e., scratched frames, exaggerated moves, flash cards ...?
 * why don't people have radio drama dreams?
 * why don't people have "pulp fiction dreams," i.e., a text-based dream printed on cheap and lousy paper?

Tell you the truth. I have had a dream with a commercial in it. I could not recall the dream itself. While I was dreaming, a man interrupted my dream with a book commercial. I returned to the dream after the sponsor of my dream has done his spamming. I woke up feeling really bad about it. My dream has a commercial in it but I could not get any money. It was the only time some greedy book seller in the Twilight Zone stole air time from me. -- Toytoy (talk) 01:50, 19 October 2008 (UTC)
 * I know I used to dream about Pokemon, in a visual style resembling the cartoon, back when I watched it. But my dreams are often a jumble of "live action" images, spoken words, and more surreal/artistic imagery, often with some books/TV images/online content integrated into the dream. So all I can really conclude is that, yes, the media we're exposed to gradually creeps into our subconscious minds just as much as any "real world" influence. 69.107.248.192 (talk) 02:58, 22 October 2008 (UTC)
 * Wouldn't this mean that before TV humans didn't have dreams?203.59.155.251 (talk) 03:16, 19 October 2008 (UTC)
 * More likely that TV sometimes influences our dreams now, whereas before TV people sometimes dreamed about what they heard on the radio, or the Sheriff of Nottingham, or the sabretooth tiger they killed the day before. Astronaut (talk) 07:16, 19 October 2008 (UTC)


 * I expect that before the existence of telly, radio, printing or gossip, that we all dreamt in cave paintings.  Sp in ni ng  Spark  14:09, 19 October 2008 (UTC)


 * I've dreamt a dream was a book I was reading, and that it was a film I was watching. I've dreamt I was in a Philip K. Dick short story. I think all those types of dream are possible. I even had sepia dreams when I was small and reading a lot of old picture books. 79.66.121.198 (talk) 15:25, 19 October 2008 (UTC)


 * When my bed faced a window, I once woke up from/through a dream in which the window (a pale rectangle) was a website. —Tamfang (talk) 20:31, 19 October 2008 (UTC)


 * I suspect observer bias. Let's suppose that we have always had some dreams in color and some in monochrome.  It's possible that before the era of television and film, nobody thought very much about whether there was color or not.  Things naturally tend to look monochromatic in dim light because the 'cone' cells in our eyes that detect color don't work well in low light levels and our 'rod' cells - that work well in low light levels - don't produce color information.  This is so ingrained into us that very few people even realise that it's happening.  So it's possible that before we saw monochromatic-in-full-daylight scenes in the movies and early model TV's - we'd have simply interpreted monochromatic dreams as happening in low light conditions.  When monochrome TV's appeared, we had this other interpretation thrust upon us - resulting in reports of seeing dreams in monochrome - then when that period went away and we all started seeing monochrome only in dim light again - that we'd go back to reporting monochromatic dreams as not being unusual - just like we don't report dim-light vision as being unusual.


 * SteveBaker (talk) 13:11, 20 October 2008 (UTC)

Is there evidence to suggest that the Black and White ness isn't age correlated? That would seem to be the simplest assumption to make, 137.108.145.10 (talk) 13:43, 20 October 2008 (UTC)


 * Monochrome images were available before the invention of BW photos and TV. Charcoal sketches are monochrome. However, if you were an ordinary poor farmer 100 years ago, you could have seen no art at all. -- Toytoy (talk) 09:23, 21 October 2008 (UTC)

Genetic mutation- Double tail gourami
I was at the pet store today looking at the fish for sale. I noticed in one of the tanks a dwarf gourami with a true split tail (double tail). It looks like a split tail betta splendens. Ive looked online for some information on genetic mutations of the gourami but havent found anything. I was curious what causes this and if there is any information available to breeding true split tail gourami.

http://en.wikipedia.org/wiki/Gourami —Preceding unsigned comment added by 69.45.184.77 (talk) 06:34, 19 October 2008 (UTC)


 * This finds double tail betta females and possibly others. If it's what you're looking for, specialised aquariums might be able to help. Julia Rossi (talk) 22:20, 19 October 2008 (UTC)

Ultimate fate of the universe
I tried pointing this out at Talk:Ultimate fate of the universe, but I received no response, so I'll repeat it here.

The graph from the section "Role of the shape of the universe" shows the accelerating universe as a sinusoidal curve, with "Now" on the inflection point. In my opinion, it seems more likely that an accelerating universe would be concave all the way along, with a constantly rising gradient. Axl ¤  [Talk]  09:01, 19 October 2008 (UTC)


 * I don't think the shape of the curve is quite right, but the inflection is. If you assume a cosmological constant version of dark energy then the curve should decelleration due to gravity initially until dark energy starts to dominate and only then does it start to accelerate.  As I recall, that transition was a few billion years ago more or less.  Dragons flight (talk) 09:25, 19 October 2008 (UTC)


 * The correct ΛCDM curve is roughly $$a(t) \propto (\sinh (t / \mbox{11 Gyr}))^{2/3}$$. The curve in that diagram has the right general shape, but it's not drawn very accurately. -- BenRG (talk) 14:14, 19 October 2008 (UTC)


 * I've replaced the image with an svg version so I could implement your maths if you like. However, I don't really see too much point as it's just a diagram and not meant to be that accurate. Durand101 (talk) 18:12, 16 January 2009 (UTC)

Gibbs free energy
ΔG0=RTlogeK

The K used here is the equilibrium constant. But there is a problem in knowing that is it Kp or Kc

If we use either of the constants the values come out to be different. Please Explain. —Preceding unsigned comment added by 122.173.65.66 (talk) 14:41, 19 October 2008 (UTC)


 * You will have to refresh my memory as to what the "p" and "c" subscripts mean (constant pressure and ??), but I believe the real equation is ΔG=RTln(Q), which takes into account concentrations of the reactants and products. Under standard conditions (superscript °), then that would mean various things (concentrations of reactants are 1 molar, STP).  This calculation of ΔG is for the instant at the beginning of the reaction.  Once the reaction starts to proceed, ΔG will change (due to mass action and Le Chatelier's principle) until it reaches zero - equilibrium. --Bennybp (talk) 20:05, 19 October 2008 (UTC)
 * Kc is the constant for concentration. —Cyclonenim (talk · contribs · email) 22:17, 19 October 2008 (UTC)


 * ΔG0 is the instantaneous free energy change at the start of a reaction, at standard conditions (273K, 1 atm, 1 molar concentrations) and constant pressure, whose equilibrium constant is K. K is generally assumed to be unitless and calculated from the "activity" of the compounds involved.  Since actvity is not directly measureable, a "surrogate" which can be measured is often used.  Kc is the equilibrium constant as calculated from molar concentrations (aqueous solutions or gasses) and Kp is the same constant as calculated from pressures.  For gases, Kc = Kp divided by (RT)Δn, where Δn is teh number of moles of gas that changes in the balnced reaction.  --Jayron32. talk . contribs  22:38, 19 October 2008 (UTC)

The shape of the orbit of the Moon over the Earth
Imagine a line from the centre of the moon to the centre of the earth. At the surface of the earth, this line forms a dot which moves with the rotating orbit of the moon, and the rotation of the earth. If this moving dot was plotted on a stationary globe, what shape would it make? Some sort of spiral? Thanks 78.149.192.49 (talk) 17:40, 19 October 2008 (UTC)
 * Hm. This may be a start for you: Orbit of the Moon.  From that, it appears that there are some rather complex motions to consider.  If you picture the moon's orbit as a big coin, the coin is at an angle to the earth's equator (called inclination) and that coin is itself "wobbling" (called precession).  The wobbling is in two different planes (parallel to and perpendicular to the ecliptic).  The periods of these two precessions is quite short, 8.5 years for one and 18.6 years for the other.  Not sure what this means for the overall pattern you are looking for, but if you can wrap your head around all of that (the article is more detailed) then there ya go.  --Jayron32. talk . contribs  18:19, 19 October 2008 (UTC)
 * If you unwrap the earth into a typical rectangular Mercator projection map - the path of the moon would be (more or less) a series of overlapping sine-waves. SteveBaker (talk) 12:56, 20 October 2008 (UTC)
 * Similar to the map that is always in the background during film scenes set in mission control. That was my first thought, but I'm a little unsure how the fact that the Earth's rotation is orders of magnitude faster than the orbit (with an artificial satellite it's usually the other way around) would affect that. I think that it would still, technically, be overlapping sine-waves, but the wavelength would be extremely long so the wave goes all the way round the Earth 28 days per period (ish, I'm not sure exactly which definition of lunar month we need). Therefore what you would actually see is basically a series of straight lines across the surface of the Earth (well, straight as in constant latitude, whether they are actually straight lines depends on the choice of projection). --Tango (talk) 13:12, 20 October 2008 (UTC)
 * Actually, it probably wouldn't be all that different. The absolute motion of the moon around the center-of-mass of the earth (the Month) is not what is relevent here, its the relative motion of the moon to the earth's surface, which is still about a 24 hour period.  The question is kinda vague, since the picture is different whether one wants to know what the pattern would look like projected on the real map of the earth OR a theoretically static earth.  The two wavepatterns would look very different, since one takes into account the earth's day-rotation, while the other only takes into account the moon's month-revolution.  --Jayron32. talk . contribs  13:54, 20 October 2008 (UTC)
 * While the longitude of the point goes in a roughly daily cycle, the latitude will go in a monthly cycle since the Earth's rotation doesn't affect where the moon is in relation to the plane of the Earth's equator. I think the OP's question was quite clear, since it specifically mentioned the rotation of the Earth, so the reference to a static Earth refers to a co-rotating frame of reference rather than actually stopping the Earth moving. --Tango (talk) 14:49, 20 October 2008 (UTC)

Thanks. So how far north or south from the equator would the dot go? I assume that at the poles, the moon is never directly overhead. 78.149.175.26 (talk) 14:11, 20 October 2008 (UTC)
 * The Moon's orbital inclination relative to the Earth's equator is (according to the infobox on Moon) "between 18.29° and 28.58°". That means the dot will never go north of 28.58°N or south of 28.58°S (and will rarely get even that far from the equator, I'm not sure precisely what determines the inclination at any given time, but the difference is almost exactly twice the inclination from the ecliptic which suggests to me that it's probably an annual cycle). --Tango (talk) 14:49, 20 October 2008 (UTC)
 * Earth's equator to the ecliptic is constant ~23&deg;; Moon's orbit to the ecliptic is constant ~5&deg;. As the Moon's orbit precesses, the 5&deg; sometimes adds to the 23&deg; and sometimes partially cancels it, resulting in the numbers you see, as you apparently guessed; though there's no annual cycle to it. —Tamfang (talk) 02:40, 21 October 2008 (UTC)
 * Ah, that makes sense. Thanks! --Tango (talk) 14:32, 21 October 2008 (UTC)

Thanks again. What prompted these questions - and what really interests me - is the track of the moon in the sky over time. Where I habitually sit, I see the moon through the window pass in an arc across the night sky during the evening. I think the centre of the curve of the arc is to the south. As the nights go by, this arc gets lower and lower in the sky. I can only see a small part of the sky through the window. I'm wondering what the track of the position of the moon would look like overall. A few nights ago I went out of the house and was surprised to see the moon in the north-east or east of the sky, I think. I'm also wondering if the moon is capable of being in any part of the sky (from my point of view) or in just some of it. If in just some of it, then how does the moon get into position to draw the arcs I have described? 78.147.35.151 (talk) 21:39, 20 October 2008 (UTC)
 * The track of the moon in the sky from a fixed point on Earth is quite a different matter to the track on Earth of the point below the moon. The moon will follow a similar path along the sky as the Sun, rising in the east and setting in the west once a day. It will never stray more than about 5 degrees from the ecliptic (the path travelled by the Sun, where that is depends on the time of year and your latitude). I suppose you are in the northern hemisphere, so the moon is getting lower and lower in the sky for the same reason the sun is - it's getting into winter. That's caused by the Earth's axis being tilted with respect to the Sun's/Moon's orbit (the sun's and moon's orbits are at pretty much the same angle (only 5 degs different), so the tilt is pretty similar). --Tango (talk) 22:02, 20 October 2008 (UTC)

Thanks, but I have to disagree with the moon getting lower in the sky with the seasons - it seems to happen about every month, not every year. And in the small part of the sky I see out of the window, the moon is more or less full. I wish there was some nice freeware software somewhere that could show what I have described. 78.151.133.172 (talk) 22:55, 20 October 2008 (UTC)
 * There is excellent astronomical software available for free that allows you to pick a point on the Earth and a time and see exactly what the night sky should look like, you can then fast forward and see what changes. I have Celestia installed on my computer, although I haven't used it in a while, and found it quite good. There are plenty of alternatives, though. When you see the moon lower in the sky, it could simply be because it's at a different point in it's path across the night sky - it will rise and set at different times each night. --Tango (talk) 14:31, 21 October 2008 (UTC)

Helicopter under a bridge?
This question has one foot in the Entertainment Desk, but it's the science side I'm asking about.

Last night I watched Terminator 2 (a documentary that hasn't been made yet:) and in one scene a helicopter flies under a fair-sized road bridge, six-lane overpass type. Now I know they built a real polyalloy cyborg for the movie, but is the helicopter shot faked? Helicopters generate downwash, so the air has to come from somewhere, seems to me having a bridge deck just over the rotor would seriously disrupt the aerodynamics - lifting the 'copter as it ate away the air above it and causing it to hit the bridge deck above.

Is it actually possible to fly a 'copter under a bridge, let's say an 80-foot span-breadth with 30-foot clearance? Thanks! Franamax (talk) 20:30, 19 October 2008 (UTC)


 * I know that they regularly fly helicopters under the Golden Gate Bridge, but that is several hundred feet high. I don't know what the lower limit would be. --71.106.183.17 (talk) 20:38, 19 October 2008 (UTC)


 * Even if the scene in the movie is possible, I cannot imagine it would be legal in the US. So the filmmakers would certainly have used special effects to simulate it.  At least it's not as obviously impossible as the helicopter scene in the 1996 "Mission: Impossible" movie.  --Anonymous, 22:12 UTC, October 19, 2008.


 * I don't remember that scene in the movie. Is it particularly spectacular? Is a big deal made of the fact that they flew a 'copter under a bridge? If not, they probably wouldn't have wasted special effects on it. Anyway, I think pretty much anything is legal if you get it approved for movie-making purposes. --Masamage ♫ 03:59, 20 October 2008 (UTC)


 * Mission Impossible scene - helicopter flies into Channel Tunnel in pursuit of high speed train to which it has rather carelessly become tethered. Gandalf61 (talk) 09:30, 20 October 2008 (UTC)


 * Sorry, I meant the Terminator scene. --Masamage ♫ 21:23, 20 October 2008 (UTC)


 * It's not obvious to me that this would be illegal, for the same reason I doubt there is any law that says don't use a bullwhip on high voltage electrical wires. It is so incredibly dumb and unusual that quite possibly no one has wasted the time required to write a law addressing it.  Dragons flight (talk) 09:36, 20 October 2008 (UTC)
 * I'm assuming in any case that the stunt would be legal. They presumably got the highway below blocked off to film, and (almost) anything is possible in movie-shoot areas (punch buggy alert, but watch the chase scene in Bullit). I'm asking physics-wise two cases: could you fly a helicopter at speed under a bridge with the parameters I described (confined space longer than it is high, 100'L x 50'W x 30'H)? And could you even edge a helicopter into that space and traverse it? We're talking a light 'copter like the ones they rent to movie companies or use for traffic reports, and no, it wasn't that spectacular of a scene. Similar to flying into the Chunnel (although that's much less likely, how would they get it back out?) - is it physically possible to perform such a maneuver? Franamax (talk) 10:50, 20 October 2008 (UTC)
 * There are probably laws about how close you can fly to solid objects, but there's no reason they couldn't have gotten permission from the relevant authorities. --Tango (talk) 10:56, 20 October 2008 (UTC)


 * The Wikipedia page Stunt seems to suggest this is genuine, but it's very vague. The page says "The killer robot T-1000 flies a helicopter in a freeway chase after a S.W.A.T. van driven by The Terminator and at one point flies under an overpass. As if to prove the stunt was done for real, the pilot attempts a second underpass, but flies away at the last second."  There is no cite for this claim. --Maltelauridsbrigge (talk) 11:50, 20 October 2008 (UTC)


 * I'd also mention "The Italian Job" (the recent remake - not the 1960's original) where there is a helicopter inside a warehouse chopping up a poor-defenseless MINI Cooper.


 * The problem is that the rotors are sucking air from above the helicopter and pushing it downwards to support it's weight. When you get close up to the underside of a bridge or other enclosed structure, that sucking causes an increase in lift - which forces the helicopter closer to the bridge and that in turn causes an even more powerful upward force.  This positive feedback effect makes flying under covered areas quite hazardous.  Flying quickly under a narrow structure like a bridge is reasonably OK because you aren't under the bridge for more than a couple of seconds - but hovering under a bridge, or inside a building or (god forbid) inside a railway tunnel - would be very hazardous indeed.


 * We can get an estimate of "how close is close?" by noting that the ground effect occurs at about one to one-and-a-half times the rotor disk diameter. Below this height, the extra pressure caused by the ground interacting with the downward-moving air column dramatically increases the efficiency of the rotors.  So when a helicopter comes in to land, it's like it hits this soft cushion at about one rotor-diameter above the ground.  That's really convenient - and the lower you go, the stronger the effect.   So I would guess that if you flew under a structure at a low enough height that there was at least (say) two rotor diameters of air between the top of the helicopter and the underside of the structure - then you'd barely notice that there was a problem.  But if you got within (say) one rotor diameter of the structure, it would go badly wrong quite quickly.   If the pilot was expecting this to happen, he could probably throttle back or reduce the collective pitch to cut the helicopter's lift - but unlike coming in to land where the negative feedback gives you a gentle cushioning effect that makes landing easy - the positive feedback sucking you upwards would be like a magnet pulling you where the closer you get, the more pull there would be.  Flying the helicopter accurately under those circumstances would be exceedingly difficult.


 * So flying 100' below the golden gate bridge with a 30' diameter helicopter is no problem whatever - but the flying-though-the-rail-tunnel thing in Mission Impossible is...Impossible.


 * SteveBaker (talk) 12:50, 20 October 2008 (UTC)


 * It says above that helicopters are regularly flown under the Golden Gate Bridge. Is this legal?


 * (I do not consider that I'm asking for legal advice here. I'm just seeking factual information about the law. Also, for the record, I'm not planning to make any such flight.)


 * If it is legal, do the applicable laws cover what size of helicopters may be used? After all, there are helicopters and then there are HELICOPTERS.


 * Similar question for fixed wing aircraft. Piper Cubs good? Concordes not good? Where is the line drawn?  Thanks, Wanderer57 (talk) 17:36, 20 October 2008 (UTC)


 * Yep - it's a similar deal. There isn't a hard line - but the bigger the wing the greater the effect.  When I was a flight simulator designer, it was a moderately well-kept secret that we deliberately put invisible walls under all of the bridges in our 3D graphic simulations so that if a pilot tried to fly under a bridge in the simulator, they'd crash 100% of the time.  The instructors who taught military fighter jocks using our simulators wanted it this way because they didn't want to encourage fighter pilots to practice flying under bridges in the simulator and then go and do something stupid in the real world once they'd gotten the hang of it.  They assumed the pilot would try it a few times in the simulator - conclude that it was just WAY too difficult and give up on the idea! SteveBaker (talk) 14:10, 21 October 2008 (UTC)


 * As far as the law part of it, I had a look through FAA flight rules. They're pretty dense but I think I found 500-foot minimum altitude in there (except TOL of course). There was an exception for helicopters and they had to be operated in a "safe manner" below the limit altitude. I suppose that would mean that you would need to file your operating plan and if it said "flying under a few bridges today" they might ask you in for a chat. Have a read through those regs and see if you can find anything better. I couldn't find where they defined Class A - D airspaces for example. Now that I think of it, maybe Sikorsky's website would have something for 'copters. Franamax (talk) 17:37, 21 October 2008 (UTC)


 * Well, at least on a smaller scale, clearly this is not impossible, as this YouTube video shows us. I don't recall the T2 scene exactly, but I believe the bridge was wider in that. -- Captain Disdain (talk) 08:16, 21 October 2008 (UTC)


 * He's under the bridge for less than a second - and it's not even as wide as the rotor disk - so the upward force effect would be pretty limited given the momentum of the helicopter. He's gotta be much more concerned over the turbulence from the vertical side-walls - which can also create aerodynamic mayhem with helicopters when you get that close to them.  You can see he's manouvering very slowly and carefully...and stunt pilots have a lot of experience with flying in odd situations like that. SteveBaker (talk) 14:10, 21 October 2008 (UTC)


 * The T2 scene had the 'copter filling maybe half the space under the overpass and flying through for several seconds. Against a black background, now that I try to recall. And flying over the second (higher and less broad) bridge makes no sense at all, I mean it's a Terminator fer-gawd's-sake, why would it chicken out? Franamax (talk) 17:46, 21 October 2008 (UTC)

Carbon-neutrality of paper waste
Does paper waste contribute to global warming, or is it an offsetting factor? Most paper waste is put in landfills and does not biodegrade over the short term. This would suggest that paper waste reduces the amount of carbon in the atmosphere, and thus offsets global warming. On the other hand, energy must be consumed in order to convert the wood into paper and to transport the timber, paper products, and waste paper. What is the net effect? John M Baker (talk) 20:55, 19 October 2008 (UTC)
 * Assuming the paper is produced from wood produced in sustainable forestry, the carbon content in the paper itself will be neutral, since new trees are absorbing carbon where the old trees were cut down. To the extent that the waste paper conributes to production of methane in the landfill (where the methane is not captured from the dump), the paper will contribute in the short term (10-20 years) to global warming since methane is a much more potent heat-trapping gas than CO2. And to the extent that the waste paper could have been diverted to a recycling stream, it will also contribute to global warming, since more energy is required to make paper from virgin wood than from recycled, and the net effect will generally be to cause increased consumption of fossil fuels. Franamax (talk) 21:23, 19 October 2008 (UTC)
 * Are we sure that most waste paper is sent to landfill? Collection and recycling of waste paper is advanced compared to many other forms of recycling. Note that one of the uses of recycled paper is cellulose fibre insulation for buildings - environmentally benign. Itsmejudith (talk) 21:29, 19 October 2008 (UTC)

Responses to the points made so far:
 * As to the sustainable forestry point: Yes, cutting the tree down is itself a carbon-neutral act, since a new tree will be planted in its place.  It's after the tree is cut down that carbon is affected.
 * Waste paper in landfills generally does not produce methane over short periods of time, perhaps not for millennia. Newspapers from landfills a half century ago remain readable.  My source is Rathje & Murphy, Rubbish!:  The Archaeology of Garbage (which I recommend as an excellent read, as well as being enormously informative).
 * My question really asks about carbon-neutrality in absolute terms, and not in comparison to some other, perhaps superior, method of disposal, such as recycling. That said, I am intrigued by the comparison to a recycling stream.  Are the incremental carbon savings from recycling greater than the amount of carbon removed from the atmosphere by burial in a landfill?  That seems intuitively unlikely, but I'm prepared to be influenced by actual facts.  Of course, there are reasons other than global warming to favor recycling.
 * I don't have statistics on disposition of waste paper, but I think most is sent to landfills. Recycling would also have favorable carbon effects, while other methods of disposition, such as incineration, generally would have unfavorable effects.  I don't know which of these effects predominates.  John M Baker (talk) 22:04, 19 October 2008 (UTC)
 * Hmm, those are some cogent points. To a certain extent, you are suggesting cutting down whole trees and burying them to sequester their carbon (not that you're saying that, but extend the argument that way...). I have no statistics on buried paper conversion by bacteria, you're right about reading old newspapers, whether that applies to non-chlorine-bleached vegetable-ink modern newsprint, I dunno. Certainly in my area, the majority of paper goes to the blue-boxes, either newsprint or cardboard/fine-paper. Of course by observation, people aren't able to recognize the pictures and words asking them not to throw in their waxed-paper milk cartons (or pizza boxes with the pizza still in them, or their old VCR in the paper bin) - so I can't estimate how much "recycled paper" gets rejected at the plant and sent to landfill. We would need to look at the energy balance - new paper vs recycled. We will always be using more new pieces of paper, how much (presumably carbon-intensive) energy do we expend to produce virgin vs. recycled material? How does that balance with the putative benefit of burying carbon for some millenia? I've got no good numbers on that and it's an interesting question. For comparison though, why don't we just cut down trees and bury them? Franamax (talk) 00:57, 20 October 2008 (UTC)
 * One minor point. I would wager that household use of paper probably pales to office/commercial use of paper. My experience in that field suggests that office workers do a very poor job of separating their recyclables leading to a great deal of supposedly recyclable goods getting dumpstered. Matt Deres (talk) 13:42, 20 October 2008 (UTC)
 * And dang, I missed a point - incineration works out, give or take 10-100 years, to be not that bad. In the case of clean incineration and efficient use of the energy, as in combined cycles of incineration to produce steam for power generation combined with district heating schemes (I'm thinking Sweden and Denmark especially), again fossil fuel use is reduced in proportion. Given a sustainable forestry scheme, the carbon is directly recycled - again, need to consider here the energy balance between producing the finished good and incinerating it (and having enough burnable material to sustain an incineration scheme). Franamax (talk) 01:06, 20 October 2008 (UTC)


 * Burying paper cut from a managed forest should be a net carbon win. Burying trees would also be a win - providing the energy you consume in doing so is small enough.  Of course nature has been solving the carbon problem by burying trees for a very long time - and that's been working out pretty well, right up to the point where humans started digging them up again (as coal) and burning them.  I very much doubt that deliberately cutting down trees in order to bury them is a good idea - it's probably better to simply leave the forest alone and let it bury its own trees - thereby saving all of the fuel and manpower needed to cut and bury.  Using wood to build houses is a net carbon win - but only so long as the total number of houses increases over time.  As soon as you reach some kind of market saturation where old houses are demolished in order to make new ones, the question becomes one of what you do with the refuse coming from the demolition of old houses.  If you bury it - then you're still winning the carbon battle - but if you burn them it's a break-even thing.


 * The underlying problem is that for the earth to reach equilibrium, we have to bury carbon at a rate equal to the rate that we dig it up and burn it. Since coal is essentially dead trees with all of the non-carbon squeezed out of them - it would take many tons of modern tree burial to cover every ton of coal dug.  When you look at the numbers - a typical mid-sized power station consumes 10,000 tons of coal per day - and consider the number of acres of trees that would represent... says that around 50% of the mass of a tree is carbon.  says that around 500 trees per acre is typical for a managed forest and that turns out to be about 8 tons per acre. So to compensate for the carbon created by just one medium-sized coal fired power station, you need to chop down, bury and replant 1250 acres of managed forest every single day.  The fastest growing trees can be cut and replanted every 10 years - the slowest, every 60 years - so to sustainably cover the carbon from one powerstation requires at the very least, 1250x356x10 or about 4 million acres of managed forest - and at the worst 1250x356x60 or about 24 million acres.  In the whole of the USA, there are about 600,000,000 acres of managed forest - which (if you buried every single tree they grew) would cancel out the carbon emissions from between 25 and 150 medium sized power plants.  Sadly, there are over 600 of those plants in the USA - so even if you eventually buried every single piece of wood and paper we ever used - you'd only be saving between a 4% and 25% of the carbon we're producing from coal power plants alone.


 * However, there are faster-growing plants than trees. So if we were serious about this, we could grow (for example) saw-grass - and perhaps reach the break-even point that way.  But the idea of turning over all of the managed forests in the USA for the entirely non-productive growing and burying of plants seems like an economic non-starter.  Replacing the coal fired power stations with nuclear power and using just a few of those 600 million acres for the intensive storage of nuclear waste seems like a much simpler proposition. SteveBaker (talk) 12:32, 20 October 2008 (UTC)


 * Yes, it's true that cutting and burying trees is a form of carbon sequestration, and one that is being taken seriously; Dyson, for example, has written about genetically engineered carbon-eating trees. My question, however, is about paper waste that would be generated in any case.  John M Baker (talk) 14:51, 20 October 2008 (UTC)
 * Going by this, pulping waste paper saves 5-7GJ/ton compared to virgin pulp. Using 57 lb carbon/MBTU for coal energy and a very ragged envelope back gives me 342 lb. carbon saved by recycling one ton of paper, versus 1000 lb. sequestered by burial (using Steve's 50% ratio). This would look like an argument for throwing the paper away. However I'm not sure on the energy intensity for coal, i.e. the conversion efficiency from primary energy to usable energy. If the efficiency is 30%, it's a wash. If it's 50%, you could feel good about throwing paper into the trash. Additionally, this depends on the assumption that all the carbon in the paper will in fact be sequestered, and this suggests that it actually supports methane production, so you're going to get a lot of it back out again over a period of 30 or so years . Maybe Steve has a better calculator than me. Franamax (talk) 22:39, 20 October 2008 (UTC)


 * No - I agree. It's a tricky thing.  So long as the energy cost of recycling 'old' paper is less than the energy cost of cutting down (and replanting) a tree and making 'new' paper - then recycling makes sense.  Remember that ultimately, the paper gets buried in a landfill one way or the other whether you recycle or not because recycled paper often goes into products that can't easily be re-recycled and therefore get buried.  If recycling was perfect and no new trees needed to be harvested ever again - then we'd have to balance whatever new use all that land was put to against the 'sequestration' of the carbon in the paper in landfills.  But if they are left as natural forests then they'll sequester carbon and eventually make coal all by themselves.  (We need to contact some landfill operators and advise them to rename their businesses "Waste sequestration" - it makes them sound like really 'green' businesses!)
 * And given the longevity of some items in landfills (see the archaeology point above), they could also use "Preserving Our Nation's Heritage". :) Franamax (talk) 17:27, 21 October 2008 (UTC)
 * "Future historic artifact repository". Yeah - I think we're on to something! SteveBaker (talk) 00:34, 22 October 2008 (UTC)

Extremely interesting discussion. While all participants have my thanks, I note that there in fact was no answer seriously comparing the carbon sequestered by waste paper in landfills with the carbon expelled into the atmosphere in connection with the production, use, and disposal of the paper (although Franamax did point out that landfills may not be all that effective at carbon sequestration). It sounds like it might be an interesting area for research. John M Baker (talk) 00:32, 23 October 2008 (UTC)