Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
Bunned. James Bunned.

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.

user:
pass:
register,


                                                                                                                                       

Gravity Reduction Device

A method of reducing the effects of gravity
  (+3, -15)(+3, -15)(+3, -15)
(+3, -15)
  [vote for,
against]

Even as a newbie, I am aware that theories are frowned on in the HB however my gravity reduction device somewhat depends on an alternative theory of gravity so bear with me while I give an outline of this theory.

I have scoured the internet for something similar to this theory without any luck which means that it is 1. naive and stoopid, 2. discredited and discounted so long ago that nobody even bothers mentioning it anymore or 3. a new theory (seems unlikely but your inputs would be much appreciated). The gravity map recently produced by ESA (see link) gave me some confidence though that it may be correct or at least have some relevance.

My theory is that gravity is an entity at the centre of all the large bodies of mass in the universe. This gravity entity has some peculiar properties in that the gravity molecules attract all mass except other gravity molecules which they repel however the force of repulsion is lower than the force of attraction which leads to this large collection of gravity molecules effectively trapped at the centre of a planet or star. The attraction force of this gravity is consumable. In other words, a given quantity of gravity can only attract so much mass before it's attractive force is diminshed to the point where the remaining force of attraction is too weak to support any more mass. This is, of course, different to the three generally accepted theories of gravity: 1. Relativity 2. that gravity is present in all mass in some form or 3. String theory or variants thereof all of which have their own anomalies that don't quite add up.

This theory supports the generally observed interactions of planets and stars and would suggest that as a star sheds mass through the expulsion of energy the gravitational force of the star would increase to the point where the star could implode in on itself. It suggests that as the earth gains mass from the sun that the gravitational pull of the earth will diminish causing the moon, for example, to move further away from the earth.

In more detail it would also suggest that the amount of gravity at any given point on the earth's surface would be dependent on the amount of mass below that point. The more mass there is the less gravity there would be (gravity being consumable). Therefore my gravity reduction device is to build a 1m x 1m x 10,000m high column of lead (lead being readily available, at least more so than the truly heavy elements). A cubic metre of lead weighs approx 12 tonnes. Below each square meter of earth there is approximately 12,000,000 tonnes of mass. The column would therefore add 120,000 tonnes of mass to that one square metre and therefore above the column there should be a one percent reduction in gravity.

The_Saint, Dec 26 2009

ESA Goce http://www.esa.int/...ALS/GOCE/index.html
[The_Saint, Dec 26 2009]

Map of Gravity at Earth's Surface http://en.wikipedia...ography_and_geology
More density = more gravity [sninctown, Dec 26 2009]

A relevant xkcd webcomic http://xkcd.com/675/
What's more likely -- that I have uncovered fundamental flaws in this field that no one in it has ever thought about, or that I need to read a little more? Hint: it's the one that involves less work. [sninctown, Dec 26 2009]

GOCE map of gravity http://news.bbc.co....ci/tech/8408957.stm
[The_Saint, Dec 26 2009]

More from xkcd http://xkcd.com/681/
and a big SETI-style shout to Randall, just in case this was a message to us [lurch, Dec 29 2009]

[link]






       I suspect that, if you're contending that extra mass reduces gravity by sort of mopping it up, you're going to find that reality barges in and starts arguing with you.   

       Also, you *are* aware of the experiments that were done to measure the gravitational constant, many many decades ago, aren't you?
MaxwellBuchanan, Dec 26 2009
  

       Wouldn't it be easier to tunnel beneath a mountain, and measure the gravity at the peak and in the tunnel? Or, measure the gravity at the bottom of a very deep mine gallery?   

       Awaiting calculations on the market value of the lead, and what proportion of world reserves it represents.
pocmloc, Dec 26 2009
  

       // if you're contending that extra mass reduces gravity by sort of mopping it up// - I am.   

       // experiments that were done to measure the gravitational constant // - I am aware of these however they would still be valid. Placing two objects near each other would create a sort of gravity channel since they would 'consume' gravity where they were placed and between them would be proportionately a greater amount of gravity causing them to move together.   

       // Awaiting calculations on the market value of the lead, and what proportion of world reserves it represents.// About $2,400 per tonne. I can't find exact numbers on reserves but it looks to be about 200 million tonnes.
The_Saint, Dec 26 2009
  

       Look up "mascon".   

       You appear to be of the mindset which, once convinced of something, takes all data to support your theory. You could stand under a blue sky, and claim its blueness is proof - Proof - PROOF! that the sky is red.   

       Gravity is *not* consumable. Many, many phenomena would act differently if it were.
lurch, Dec 26 2009
  

       // Look up "mascon".// - But this is exactly the point. It is assumed that there must be a concentration of mass below the basins on the moon since the gravitational pull is greater at these points however these are assumptions. They could equally (and more obviously) show that there is less mass at these points therefore the corresponding increase in gravity.   

       And no, my mindset is very different to what you describe.
The_Saint, Dec 26 2009
  

       Imagine a sphere of matter. Quantify its gravity. Cover sphere with another layer of equal mass. By standard theory, gravity has increased; by your theory, diminished. Correct?
lurch, Dec 26 2009
  

       // By standard theory, gravity has increased; by your theory, diminished. Correct? // - Correct.
The_Saint, Dec 26 2009
  

       So, if I take a 300 lb. lead ball, and encase it in 300 lb. of lead, the resulting gravitational force should be less than that of 300 lb. of lead?
lurch, Dec 26 2009
  

       That needs a bit of explanation. I am suggesting that the lead ball has no gravitational force of its own therefore encasing it in another 300 lb of lead will have no effect on anything else. But I possibly misunderstood.
The_Saint, Dec 26 2009
  

       What property, then, would imbue an object with gravity? Given that it would not be a property of mass? Just a caprice of the universe as to whether "gravitational molecules" had decided to inhabit the poor thing?
lurch, Dec 26 2009
  

       Not sure I get your point. Nothing would imbue an object with gravity. Gravity would be an entity on its own that would attract all mass. There would be no requirement for an object to have any gravitational force or molecules of its own.
The_Saint, Dec 26 2009
  

       Why, then, does the actual force of gravity, by observation and measurement, follow the equation: F = G *M1*M2/r^2   

       'twould seem a pity to throw away something that works so well in favor of something that doesn't agree with observation.
lurch, Dec 26 2009
  

       //Gravity would be an entity on its own that would attract all mass// How come everything is not all in the same place then?
pocmloc, Dec 26 2009
  

       // How come everything is not all in the same place then// I dunno, but it would make it easier to find my specs.
AbsintheWithoutLeave, Dec 26 2009
  

       // 'twould seem a pity to throw away something that works so well in favor of something that doesn't agree with observation // Observation doesn't follow existing gravity theory which is why theorists come up with ever more elaborate dark matter, one dimensional strings, 11 dimensions, etc. Basic observation would suggest that gravity would be strongest at the equator and weakest at the poles (being generally accepted that there is more mass at the equator) however the converse is true. Basic observation would suggestion that the moon should be drawing ever close to the earth but the converse is true.   

       // How come everything is not all in the same place then?// - This is one of the anomalies of current gravity theory but with this theory the gravity molecules would repel each other and gravity would be consumable which would provide an explanation.
The_Saint, Dec 26 2009
  

       [The Saint] You'll get all kinds of brickbats over the coming days, so let's cut to the chase.   

       (A) Does your theory make predictions that are in line with observations? In particular, as lurch was getting at, why do objects appear to have a content of "gravitational molecules" proportional to their mass?   

       (B) Does it make any predictions beyond the data on which it is based? and   

       (C) Is it testable?   

       (D) Do you think we should replace the cumbersome notation of "gravitational molecules" with something more concise, such as "phlogiston"?
MaxwellBuchanan, Dec 26 2009
  

       Thanks [MaxwellBuchanan], to answer:   

       A: Yes but remember that a lot of observations rely on the received wisdom that gravity is present in all matter. The example of mascon referred to earlier is one such. When it was determined that there was more gravity above certain lunar basins there could only be one explanation if gravity was present in all matter and that was that there must be dense matter below the basins. It has never actually been proven either way but becomes fact following assumption. In terms of the general movement of the stars, the planets and the universe in general then yes, my theory does make predictions in line with observation.   

       B. Not exactly but it does suggest different outcomes than received wisdom would suggest. An example would be that the earth, which is gaining mass, would eventually have a much lower gravitational force possibly leading to the loss of the atmosphere and becoming a dead planet.   

       C. Yes. The ESA GOCE project is, in effect, testing this theory by mapping gravity across the planet. It has shown that there is greater gravity above the poles than at the equator. A simple experiment though would be to weigh a lump of something and then place a dense object underneath it to see if the weight of the object increases or decreases but this requires some fairly sophisticated scales to be accurate.   

       D. Ooh, unfair.
The_Saint, Dec 26 2009
  

       Would this work with something which was dense but was not lead? For example, would granite work?
MaxwellBuchanan, Dec 26 2009
  

       Yes, I would expect the outcome to be relative to the density of the object.
The_Saint, Dec 26 2009
  

       (A) Well, then, the experiment has already been done, surely? The average alp is mostly granite. According to your theory, then, gravity ought to be weaker on top of it (and, in particular, weaker than expected given the greater distance from the centre of the earth). Yet such is not the case.   

       (ii) Also, under your theory, how is it ensured that all bodies contain a quantity of "gravitational molecules" which is proportional to their inertial mass? And how do you make your lead tower free of such "gravitational molecules"?
MaxwellBuchanan, Dec 26 2009
  

       The lunar mascons also show up as positive deviations in inertial moment. That would be negative if they were areas of lower, rather than higher, density.   

       Also, on earth, magma plumes (such as the Hawaiian Islands, Yellowstone, south end of the Red Sea) have been identified by satellite path deviation as having positive gravitational anomalies. That these areas are also of increased density is confirmed by seismic studies, and (particularly in the case of the Hawaiian Islands) direct sampling.   

       Some of the studies referred to on Wikipedia and what-not are pay-to-view, but I can probably get you a copy if you'd be interested. (One of them has "Sagan, C." as a co-author - I'm interested in that one myself!)
lurch, Dec 26 2009
  

       The Goce map suggests otherwise. Gravity is shown as being weaker above the alps and stronger above the Netherlands. The same is true over the Andes where gravity is weaker and then stronger above the hinterland behind the Andes.   

       On the second point, the 'gravitational molecules' would, by default, want to be a the centre of the mass they are attracting. A 'gravitational molecule' could not exist at the edges of this mass since it would then attract the mass back around it (would move back to the centre).
The_Saint, Dec 26 2009
  

       Perhaps I didn't make my second point clearly. What I meant was, how is it ensured that an object with ten times more inertial mass also contains ten times more gravitational molecules?   

       (Also, as an aside, why call them 'molecules'?)
MaxwellBuchanan, Dec 26 2009
  

       Where is the gravitational map you're looking at? (I spent an hour trying to get something from the GOCE site; two had no units of measure, one had the UOM printed in white on top of the (white) antarctic ice cap. Grrr...)   

       Of the ones I have found, they're all "corrected" data: one being "difference from geoid" (but doesn't say *which* geoid), another "difference from previously measured values" (which is just showing off the higher resolution, but the data points are meaningless without knowing what the previous values were.)
lurch, Dec 26 2009
  

       [saint], if you build a lead column sunk into the Earth, there will be an increase in gravitational force due to the increased density. See links. So, I think this is bad science.
sninctown, Dec 26 2009
  

       [sninc] Thesaint is arguing for a different model.
MaxwellBuchanan, Dec 26 2009
  

       [MaxwellBuchanan] still not sure I understand your second point however I'll give it a go. I also don't know why I started calling them molecules, perhaps you were right with phlogistons so I'll now call them g-phlogistons.   

       Assume a starting point of a mix of g-phlogistons and assorted mass scattered through the universe by an unknown event. The g-phlogistons attract a definitive amount of mass but repel each other. The g-phlogistons are individually surrounded by the mass they have attracted and the resulting bodies collide to the extent that the g-phlogistons are brought together (snooker ball effect) and are then trapped by the accumulated mass. 2 g-phlogistons can support twice as much mass as 1. Collisions continue growing the bodies in size until the bodies reach a state of equilibrium where collisions are unlikely but they are in a semi-perpetual state of attraction and repulsion. In other words each body still has sufficient residual gravity to attract other bodies around it but not enough to overcome the repulsion between the two cores of g-phlogistons. The fact that some bodies may have grown larger than others as the result of collisions would be accidental.   

       [lurch] I will put up a link to a full map I found on the BBC website. Can you expand on the lunar mascons.
The_Saint, Dec 26 2009
  

       I dunno, thesaint, it seems like a kooky idea to me. I guess if I had to put my finger on it, I'm worried about this idea that your g-things are distributed uniformly with respect to mass as you describe. I'd be happier if the g- things were somehow inextricably linked to mass.   

       An example: you might argue that all bodies in the universe should have an equal proportion of heavy elements for a similar[ish] reason.   

       Also, you have a problem of divisibility/unification. You need to consider what happens when you join/split bodies. Your g-things will have to behave in a very odd way to have the same additive properties as gravitational mass is observed to have. (They will also have to be able to move freely through any mass, at the speed of light, by the way.)
MaxwellBuchanan, Dec 26 2009
  

       I think we should call them G-strings.
DenholmRicshaw, Dec 26 2009
  

       I'm calling farce.
WcW, Dec 26 2009
  

       Under your model, since your gravitational entities repel each other, the formation of a black hole, neutron star, or pulsar would be impossible.
lurch, Dec 26 2009
  

       Why would a black hole, neutron star or pulsar become impossible? My theory suggests that they are absolute outcomes of a star shedding its mass to the point where the core of gravity becomes so strong that the star implodes in on itself.
The_Saint, Dec 26 2009
  

       So under that special case, the g-whatsits no longer repel?   

       The GOCE maps shown in the bbc news link are some of the ones I was complaining about. Note that neither one of them gives any units of measure. Nor does it explain exactly what it is measuring. (I kind of have a suspicion that it's rate-of-change: if there's a spot of increased gravity, the map is showing an increase in geopotential approaching the spot, and then a decrease after crossing it. Hence the bands along the Andes, etc; the red-dot/blue-dot effect at Sandwich Islands, Yellowstone...) The lower map does specify that it's difference compared to the EIGEN-5C map, which is a potpourri of data from GRACE, LAGEOS, surface gravimetry, GPS levelling, and mathematical smoothing. Urf.   

       I'll try to find (I think it's in one of the papers I mentioned) about the lunar mascon / inertial moment thing. It affects orbital mechanics going around the moon - the point at the center of a circular orbit around the moon is not the geometric center of the moon.
lurch, Dec 26 2009
  

       [The Saint] The current gravitational model perfectly describes and predicts gravity. It does match up with every observation made (I'll grant "dark matter" is needed to explain stellar/galactic movements, but dark matter is much more probable than the basic theory being wrong). So that much of your statement is wrong.   

       What current gravitational theory doesn't do, and the main reason for the new theoretical frameworks, is explain why it works the way it does. Since your theory cannot predict the behavior of two masses, nor explain that behavior, and the existing theory can do one of the two, which do you think is better?   

       also   

       Why does "basic observation suggest that the moon should be drawing ever close [sic] to the earth" Gravitational theory says it should remain constant without outside forces. Atmospheric braking is negligible, nothing else is in play. The only outside force is the transfer of rotational inertia, which tends to move it away.
MechE, Dec 27 2009
  

       [MechE] Which of the current gravitational models are you referring to. String theory is not an enhancement to relativity, it is an alternative theory. Gravity is one of the last great unknowns.   

       // your theory cannot predict the behavior of two masses, nor explain that behavior // I may not have got to the point of quantifying in numeric terms but it absolutely does predict and explain behaviour.   

       With regard to the moon, all things are not remaining equal. The earth is gaining mass which should mean an increase in gravitational pull on the moon. Admittedly there are a number of other factors that come into play.
The_Saint, Dec 27 2009
  

       "Does this theory make my mass look big ?"
FlyingToaster, Dec 27 2009
  

       // The more mass there is the less gravity there would be //   

       Obvious contradiction.
Inyuki, Dec 27 2009
  

       [The Saint] Again, there is only one gravitational theory in terms of the behavior of mass in the observable range and it results in the equation [lurch] mentions above. The unsettled bits deal with why this is the case, not what happens.   

       If I use a sensitive meter to measure the gravitational field of a lump of material, then machine half the material away, I will get a reading half as strong (assuming equal distance). Unless you're telling me that the machining removes half of your "gravity molecules" in which case every particle must have it's own "gravity molecule", which makes it indistinguishable from the current theory, except that it adds an unnecessary actor. In which case, see William for a shave.   

       Oh, and using the GOCE map to support your theory is untenable, since it uses meters that depend on the current understanding of gravity to get it's data.
MechE, Dec 27 2009
  

       // nothing else is in play //   

       Actually, tidal drag is slowing your Moon down. Some of the energy to move the oceans up and down is coming from the kinetic energy of the Earth-Moon system (there are Solar tides as well, hence the "Spring" and "Neap" tides).   

       If you would like it speeded up again, we can offer you a fixed price for the job.
8th of 7, Dec 27 2009
  

       [marked-for-deletion] Bad science. The behavior of gravity is well established, and doesn't resemble your theory in the slightest.
ldischler, Dec 27 2009
  

       Gravity Behaving Badly then?
blissmiss, Dec 27 2009
  

       What y'all think - should we lobby for "xkcd675" to be a reason for [MFD]?
lurch, Dec 27 2009
  

       Clearly I need to deal with a bit of scepticism.   

       Firstly MFD for bad science is bollocks. Claiming that the behaviour of gravity is well established suggests you wouldn't know bad science if it bit you on the bum, married your daughter and smoked your pipe.   

       [MechE] I am proposing that your lump of material has no gravitational component of its own, molecules or otherwise. I am not aware of any sensitive instruments that can measure the gravitational component of a lump of material other than in relation to the gravity of earth as a whole. My theory accounts for this as noted earlier - "// experiments that were done to measure the gravitational constant // - I am aware of these however they would still be valid. Placing two objects near each other would create a sort of gravity channel since they would 'consume' gravity where they were placed and between them would be proportionately a greater amount of gravity causing them to move together."   

       Using the GOCE map is tenable. To clarify one aspect: I am not suggesting that there is not a relationship between mass and gravity however conventional wisdom dictates that gravity is relative to mass. This is itself a theory without proof. Part of what I am proposing is a contra view that mass is relative to gravity. Semantics but important semantics. It doesn't mean that everything changes but it may solve some of the anomalies that exist as shown by the GOCE map.
The_Saint, Dec 27 2009
  

       I had you figured the first time around. The sky is *blue*, kid.   

       //I am not aware of any sensitive instruments that can measure the gravitational component of a lump of material other than in relation to the gravity of earth as a whole.//   

       Go READ the Cavendish torsion-balance experiment. That's EXACTLY what it does.   

       Which brings up a point: which texts and studies have you read already? (Besides the pretty-colored GOCE map, which you haven't yet realized doesn't even give units of measure)
lurch, Dec 27 2009
  

       The Cavendish torsion-balance experiment demonstrated clearly that two objects would move towards each other. As I have stated before, under this theory placing two objects near each other would create a sort of gravity channel since they would 'consume' gravity where they were placed and between them would be proportionately a greater amount of gravity causing them to move together.
The_Saint, Dec 27 2009
  

       Really? Show math, please.   

       (BTW - the Cavendish experiment has been repeated many, many times. The sensitivity is great enough to show variances far smaller than local place-to-place differences in gravity. If, as you say, the device were just consuming local gravity, the local variance would show up as variances in the measured force. It doesn't. It was *looked for* - particularly by skeptics who weren't sure that the resulting quantity should be called the *universal* gravitational constant.)
lurch, Dec 27 2009
  

       [marked-for-tagline]   

       "Really? Show math, please."
normzone, Dec 27 2009
  

       // Really? Show math, please. // - Bear with me, this is going to take a few days if I am going to pull this off.
The_Saint, Dec 27 2009
  

       //Bear with me, this is going to take a few days// - you mean to say, after claiming a method and theory, you still need to develop a math framework for it? You've been telling us how the numbers are going to fall out - how do you know?   

       Oh, well, if you want to "study to the test", as it were, we might as well show you what the test questions are going to be.   

       Your math framework will be checked against the following situations, where the standard model is known good:
1) an apple falling from a tree
2) the moon orbiting the earth
3) negative gravitational anomaly when going down a mine shaft (it's a trap! :)
4) the precession of the orbit of Mercury (Newtonian gravity fails on this one, but is rescued by relativity. This is actually beyond my math level, but if you're willing to put out the work, then I will do likewise)
5) Spacecraft velocity anomaly (Again, standard gravity fails here. Your chance to shine.)
  

       (This is a substantially higher level of rigor than is normally required on the HB. Usually there's just an increase in the level of insults until everybody gets bored and wanders off.)   

       <edit>Oops, I forgot one of the canonical tests - by your permission, to be added as number 0:
0) two balls of different masses, dropped simultaneously from a balcony on an architecturally unsound tower</edit>
lurch, Dec 28 2009
  

       I am getting rigors just from the prospect of a real mathematic duel! The Champion, Gravity (in the silver trunks) as represented by the good lurch, vs the daughter-marrying pipe smoking Gphlogravicity (in the silver Speedo) as represented by the dubious Saint. Go Go, Gphlo! Bite that bum!
bungston, Dec 28 2009
  

       //I am not suggesting that there is not a relationship between mass and gravity//   

       No, just suggesting that, however perfectly correlating they happen to be; it is more likely that they have nothing to do with each other and that their merely coincidental relationship is really a mysterious and as yet discovered particle that can occupy the same space as mass and both attract and repel like mysterious and as yet discovered particles.   

       Occam does not approve.   

       Oh, and you can't stack that much lead. It wouldn't support it'self.
MikeD, Dec 28 2009
  

       Not to mention that the mass required to reduce gravity by 1 percent would be closer to 4E13 tonnes at 5,000 meters. Put that in a solid sphere with a 5000 m radius, and you'd need a material 7 times as dense as lead. That's with normal gravity. With the gravity of this theory, the "gravity reduction device" doesn't work at all, as the "gravity entity" of the lead would have been lost to the earth's core long ago. Not that it matters, as the invention was obviously included just to avoid an MFD for theory.
ldischler, Dec 28 2009
  

       For the record, I think this is idea is whacko. But I defend his right to be whacko.   

       (To be truthful, TheSaint, I think you've been too quick to dismiss possibilities [1] and [2] in the second para of your idea.)   

       And, in any case, it is extremely good fun and good mental excercise to work out the numbers, and see how far you can get with something like this. So, go for it.
MaxwellBuchanan, Dec 28 2009
  

       [bungston] - //Gravity (in the silver trunks) as represented by the good lurch// - Actually, my kids jokingly refer to me as "Ogg, beloved of Gravity" - not because I champion its cause, more for the sheer magnitude of potential energy I represent when standing on top of a stair. :)
lurch, Dec 28 2009
  

       /the sheer magnitude of potential energy I represent when standing on top of a stair./   

       This scenario might be substituted for the tired old apple and tree currently scheduled for round 1. Perhaps one large stair instead of many, to keep things clean. There could be a tarp at the bottom for the same reason.
bungston, Dec 28 2009
  

       //might be substituted// - thanks, but no - 1 and 2 need to be together as stated, as they are the original "answers pretty closely" Newtonian pair.
lurch, Dec 29 2009
  

       [The Saint] Please discuss my comment on machining away half the material from a lump in relation to the torsion balance meter results. What causes the balance to respond less to the machined mass under your theory.   

       It appears that your theory says it should respond more as there is less mass to take up the gravity located at the center of the mass.   

       I firmly agree with MFD bad science.
MechE, Dec 29 2009
  

       A new theory can't say that measured facts don't exist or are wrong but it can make those facts be seen in a different light or in a new perspective.   

       Is 'consume' the right word? How about displace.   

       It would be great leap(probably into the unknown) to gain understanding of gravity's tiny incremental how.   

       Or you could just find a new fact.
wjt, Dec 29 2009
  

       Sadly I am going to have to concede on this one, option 1 it is. Having done some fairly lengthy investigations of the maths and the science I have to conclude that gravity is relative to mass and accept the bad science verdict.
The_Saint, Dec 29 2009
  

       Ah well. It was fun.
MaxwellBuchanan, Dec 29 2009
  

       //Sadly// - don't be. They say a person learns something new every day, but the fact is it is only rarely that a person tackles a problem, wrestles it into submission, and comes away with a better understanding in spite of preconceptions: those days are to be cherished.
lurch, Dec 29 2009
  

       So gravity's "mass relativistic how" is still an abstracted black box, then?   

       My kiddish "how" is not really that satisfied.
wjt, Dec 30 2009
  
      
[annotate]
  


 

back: main index

business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle