Ancient and ArchaeologyÌý permalink
weight on the world
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Message 1.Ìý
Posted by brushstroke (U14041781) on Monday, 3rd August 2009
i just wondered if it had ever been "roughly calculated how much weight man has placed upon the world in the form of buildings etc:"
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Message 2
Posted by Nik (U1777139) on Monday, 3rd August 2009
lets do it now... but first we have to define some things:
First we cannot add weight on the earth unless we use extra terrestrial materials. Then if referring only to the weight of the buildings (and lately machines) we have built so far in our 300,000 years of existence we really have again to define what is in and what is out: Do we include the surface buildings or the subterranean ones too? Are underwater structures included (port protection for example). Do we calculate only the buildings currently above the surface or all those that have existed in history and prehistory - note that billions of those ancient ones have retaken the form of common raw materials by now or reused directly in later constructions (so we will be calculating the same weight multiple times!).
Heheh... I find this simply amusing. But of what use that would be? -
Message 3
Posted by brushstroke (U14041781) on Tuesday, 4th August 2009
i understand that we can,t add weight,like if you mix a cubic metre of concrete the seperate materials should weigh the same weight as the cubic metre weighs when mixed, but what about say every ton of coal that is burned surely its end weight is reduced
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Message 4
Posted by Stoggler (U1647829) on Tuesday, 4th August 2009
but what about say every ton of coal that is burned surely its end weight is reducedÌý
In terms of the weight on earth, it's still unchanged. When burning coal, you end up with ashes which of course weigh something. Add to that all the particulates released into the atmosphere in the process of burning and you end up with the same mass as before the burning commenced, the only difference is that the chemical process of burning has resulted in seperating the elements that made up the coal. -
Message 5
Posted by Andrew Host (U1683626) on Tuesday, 4th August 2009
Presumably it's fractionally lighter thanks to the expensive toys we've shot into orbit and beyond...
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Message 6
Posted by islanddawn (U7379884) on Tuesday, 4th August 2009
I don't think we've added much at all. It is not like we are importing products from another planet to add to the original weight of the earth.
The stone we build with, the clay for the bricks, tiles etc, the sand for the cement and glass, the wood from the trees, the minerals we mine to make iron or whatever were all here and adding their weight in their original forms. All we have done is altered that form into something we can use, not added anything extra to what was already here.
If anything it is probably man and animal who have increased the weight placed on the earth as our populations have multiplied tenfold, unlike our natural resources. -
Message 7
Posted by PaulRyckier (U1753522) on Tuesday, 4th August 2009
Re: Message 6.
Islanddown and now I forgot your name. I remember it was with an è? Hmm...Thérèse???
Therese, you forgot the water in our populations...98% I learned at school...or was it 89%...and the rest are ashes...remember the bible...you are made from ashes and to ashes you will return...also heard at school...
Couldn't resist to tease some old friend.
Warm regards to the one down on that Greek island.
Paul. -
Message 8
Posted by TwinProbe (U4077936) on Tuesday, 4th August 2009
Hi id,
You're teasing brushstroke right? The earth is a closed system within which mass is conserved, whether you make concrete or babies.
Andrew rightly points out a highly insignificant way in which the mass of the system is reduced; similar permanent losses of light gases will occur from the atmosphere into space. The good news is that the mass of the earth is increased by bombardment with extraterrestrial meteoroids to the tune of 10^7 to 10^9 kg/year.
But fascinating though this is, is it history?
TP -
Message 9
Posted by islanddawn (U7379884) on Tuesday, 4th August 2009
And here I was thinking that I was being subtle!
You're right TP, it ain't history. -
Message 10
Posted by PaulRyckier (U1753522) on Tuesday, 4th August 2009
Addendum to message 7 and re: message 9.
Therese,
I now just see that it is "islanddawn" instead of "islanddown". Utmost excuses, the "down to a Greek island" was therefore inconvenient. I hope to make it again "good" with this splendid photograph of an "island dawn":
Hope that Andrew allows this small aside between two "still" I hope old friends.
Warm regards,
Paul. -
Message 11
Posted by englishvote (U5473482) on Tuesday, 4th August 2009
Andrew
Presumably it's fractionally lighter thanks to the expensive toys we've shot into orbit and beyond...
Ìý
Being a bit harsh there aren’t we Andrew?
The history of space exploration is worthy of more than just being dismissed as toys, isn’t it? After all where would the Â鶹ԼÅÄ internet pages be without satellites? -
Message 12
Posted by Frank Parker (U7843825) on Tuesday, 4th August 2009
Presumably it's fractionally lighter thanks to the expensive toys we've shot into orbit and beyond...
Ìý Being overly pedantic I would say that the bits that are in orbit are still subject to Earth gravity (so not a loss). So it's only the bits "beyond" that reduce the Earth's total mass - and yes, it's physics, not history!
(Heavens, I can foresee someone pointing out that the moon is in orbit round the Earth so maybe I'm wrong??) -
Message 13
Posted by Frank Parker (U7843825) on Tuesday, 4th August 2009
Of course, we could modify the question slightly and ask what has been the impact of moving stuff around - all that steel, for example, that was contained within ores deep underground and is now in skyscrapers on the other side of the planet - presumably that moves the location of the Earth's centre of gravity by a whisker or two!
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Message 14
Posted by brushstroke (U14041781) on Tuesday, 4th August 2009
ah now we are getting to the point i was hoping to get to,we here all this talk about a few degrees temperature rise could make all this difference in global warming,could the rising water levels in the future have any bearing on the weight distribution on the planet
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Message 15
Posted by TwinProbe (U4077936) on Wednesday, 5th August 2009
Hi brushstroke,
I don't know where this thread is going and i think you might be more up-front about 'the point you were hoping to get to', and why, and what it has to do with history.
The tectonic plates on which continents sit 'float' on semi-liquid magma. If ice accumulates on the land masses then the increased weight means that they are pushed further into the magma. If the ice melts the weight is removed and, over thousands of years, the land rises again, with the result that the local sea level appears to fall. So that today Scotland is rising following the melting of its ice sheet at the end of the last period of glaciation.
If there is global warming then the ice sheets over the arctic and antarctic will melt. The north pole is over an ocean but those areas where major ice accumulation is over land will rise. The overall effect on sea level is more complicated (too complicated for me in fact); there will be thermal expansion of sea water as it warms and (as I believe a less significant factor) the melting ice will contribute to the total volume of the oceans.
Despite these changes the overall mass of the earth will be unaffected for reasons already stated.
TP -
Message 16
Posted by Andrew Host (U1683626) on Wednesday, 5th August 2009
Hi englishvote,
Ha ha yes - I was in a flippant mood yesterday!
Andrew -
Message 17
Posted by an ex-nordmann - it has ceased to exist (U3472955) on Wednesday, 5th August 2009
Building weight is not a constant in any case. Just take London as an example.
Hampton Court, for instance, is known to have become almost a ton lighter in 1547 on the occasion of Henry VIII's demise, though this was temporarily reversed in the late 19th century whenever his descendant Victoria visited it.
The Old Bailey in London is also subject to huge oscillation in tonnage dependent as it is on the weight of the evidence being presented on any given day.
Broadcasting House in Portland Place received a double whammy in weight gain when it abandoned the Light Programme in 1967 and later became home to several thousand heavy metal records, a library full of weighty discussion programmes and occasionally even Melvyn Bragg.
The Houses of Parliament, it is claimed, carry much less weight than in years gone by, though in recent months have become home apparently to the nation's weight of expectation regarding the government's handling of the current credit crisis. The government's predilection for white elephants can only accelerate this particular phase of tonnage-growth, one feels.
And of course this is all before one even considers the ambiguous value which can be ascribed to schools, police stations and government offices, the denizens of each being in regular receipt of London Weighting, but the actual tonnage of which is the subject of perennial dispute. -
Message 18
Posted by Andrew Host (U1683626) on Wednesday, 5th August 2009
Overall the upshot is that humans are good at moving stuff about but the extra-terrestrial stuff - until recently - requires rather more cosmic forces.
Is there any kind of estimate of the amount of material accrued on the planet via comets, meteors etc?
Moreover - and to tie this more firmly into the A&A theme - are there any examples of said materials being being discovered/identified/revered in ancient cultures?
Andrew -
Message 19
Posted by Andrew Host (U1683626) on Wednesday, 5th August 2009
Hi TP,
Overlooked your message 8... -
Message 20
Posted by an ex-nordmann - it has ceased to exist (U3472955) on Wednesday, 5th August 2009
The Black Stone sitting at the core of the devotional Ka'ba in Mecca is by tradition regarded as a meteorite. No testing is allowed to verify things one way or the other but the more likely explanation of its origin based on observational evidence is that it is glass, probably indeed from meteorite impact.
Classical Greece and Rome was littered (literally) with devotional meteorite fragments. The Temple of Apollo in Delphi, for example, reputedly contained one such, the Greeks having believed that the stone was cast down by Zeus (or Cronos). Prior to that it had undergone a rather fanciful existence. Rhea, understandably fed up that Cronos kept devouring their children every time they were born, decided to substitute baby Zeus with the stone, which the old codger duly scoffed up. After Cronos was dethroned he disgorged the stone in a fit of pique and either threw it himself in his rage or else Zeus threw it down as he saw it as a competitor, depending on who was telling the story.
One of the loony emperor Elagabalus's day jobs prior to 218CE had been guardian of a conical black stone in Emesa in Syria, a meteorite which had long been revered by believers in El-Gabal, and which he duly promoted to god upon his own advancement. Much to the locals chagrin he even built a temple to house it on the Palatine. Neither the stone nor Elagabalus survived much longer.
Closer to home, a fragment of a standing stone which tradition places at the centre of the religious cult which St Patrick traditionally stamped out through the christian tactic of massacring its priests while they worshipped round it, and which ended up being stored as an object of christian veneration in a nearby church, was recently tested and shown to be of meteoric origin. -
Message 21
Posted by islanddawn (U7379884) on Wednesday, 5th August 2009
Dear Paul,
If spelling my name wrong means you are going to send such lovely photographs then you must feel free to do it more often. But to tell the truth I didn't even notice the misspelling, I really must see about getting a new pair of glasses!
However I do feel that if Nordmann can cope with being called Norman (on such a regular basis) by our Greek friend Nik, the occasional Islanddown should not too much of a problem.
All the best
Therese. -
Message 22
Posted by Nik (U1777139) on Thursday, 6th August 2009
Hehehe... I think Nordmann knows he has called me so many names so calling him out of speed Norman is not something he will complain about ... greetings to all.
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Message 23
Posted by Mutatis_Mutandis (U8620894) on Saturday, 8th August 2009
Well, there is also such a thing as the energy-mass equivalence: E=mc^2.
Among other things, this translates in a mass deficit in exothermic reactions. When you perform an reaction that releases energy, the end product is slightly lighter than the sum of the starting materials, after it has released the excess heat into the environment. The total mass of the planet would not change by this -- unless it radiates some of the energy into space. And that it probably does, for most of the energy we use gets finally converted into heat and radiates out. We store some small fraction of the energy by e.g. lifting things to higher places, but most of our activities could be described as attempts to heat up the universe.
We probably have made the planet lighter by this process. We extract fuels (fossil and nuclear) from the crust and burn them on the surface, where part of the stored energy gets lost into space. This results in a small mass loss. It is a tiny fraction, but assuming that we are burning about 8 billion tons of carbon fuels every year and we get roughly 40 MJ per kilogram out of it, then the energy release would be equivalent to a mass of 3.5 ton per year. Another estimate is that global energy consumption now is about 5E+20 Joule/year from all sources, which would be equivalent to over 5 tons.
Of course we also have external influences, especially from the sun: Due to the greenhouse effect, we are retaining more energy on the planet than it otherwise would. However, this seems to have comparatively small impact on its mass. As a very rough estimate I find that an increase of the temperature of the atmosphere by 1 degree Celsius makes the planet around 60 tons heavier. -
Message 24
Posted by Mutatis_Mutandis (U8620894) on Saturday, 8th August 2009
> As a very rough estimate I find that an
> increase of the temperature of the atmosphere
> by 1 degree Celsius makes the planet around
> 60 tons heavier.
Oops... And that is not a comparatively small impact of course, but one that reduces the human contribution to a relatively small factor. -
Message 25
Posted by PaulRyckier (U1753522) on Saturday, 8th August 2009
Re: Message 23 and 24.
Mutatis Mutandis,
I wasn't expecting less (weight) from you.
Kind regards and with esteem,
Paul.
PS: An admirer...
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