Can building big buildings make the world lop sided?
Discussion
I was pondering this the other evening. Firstly, I’m no physicist and I did start thinking about this after enjoying some wine.
Take somewhere like Manhattan, HK or Dubai. They have got loads of tall heavy buildings in one place. Clearly the materials for those buildings came from somewhere else. Does such a high concentration of weight in a given area (and the removal of a broadly similar amount of weight elsewhere) have an impact on the earth’s position (ie does it rotate slightly under the weight)
If I were to put a football in a bowl of water and press down in one place, the ball would rotate in the direction of the force being applied. Does / can the same happen to the earth?
Take somewhere like Manhattan, HK or Dubai. They have got loads of tall heavy buildings in one place. Clearly the materials for those buildings came from somewhere else. Does such a high concentration of weight in a given area (and the removal of a broadly similar amount of weight elsewhere) have an impact on the earth’s position (ie does it rotate slightly under the weight)
If I were to put a football in a bowl of water and press down in one place, the ball would rotate in the direction of the force being applied. Does / can the same happen to the earth?
It is thought that the Tibetan Plateau is still bouncing back up, along with parts of the Antarctic and the Arctic where the ice sheets are thinning.
The Earth is probably lop-sided anyway, as the land masses are unevenly distributed around the globe.
A few buildings are comparatively insignificant in the Grand Scheme of Things.
Alternatively, too many tall buildings too close to one edge of the Flat Earth could cause it to overbalance and slide off the back of the Giant Turtle.
We should be careful.
The Earth is probably lop-sided anyway, as the land masses are unevenly distributed around the globe.
A few buildings are comparatively insignificant in the Grand Scheme of Things.
Alternatively, too many tall buildings too close to one edge of the Flat Earth could cause it to overbalance and slide off the back of the Giant Turtle.
We should be careful.
romeodelta said:
I looked this up once as I had the same thought and concluded the theory is sound, but the effect is negligible due to the overall mass of the earth.
Interesting question though.
This is correct. The mass of the Earth is 6,000,000,000,000,000,000,000 tonnes.Interesting question though.
A skyscraper has a mass of 500,000 tonnes.
So 12 skyscrapers would still be only 1/1,000,000,000,000,000 of the earth. My maths may be faulty (!) but the general concept is about right.
Try scaling that to sticking a coin to a football. It would have to be a small fraction of a coin.
Same concept though is sending spacecraft up, all their mass came from the earth, so we are actually altering the earth's orbit round the sun by reducing its mass. That's what's causing climate change I reckon, not all the CO2 nonsense. So let us keep using our petrol cars ...
M4cruiser said:
Same concept though is sending spacecraft up, all their mass came from the earth, so we are actually altering the earth's orbit round the sun by reducing its mass. That's what's causing climate change I reckon, not all the CO2 nonsense. So let us keep using our petrol cars ...
When doing your spacecraft maths, don’t forget to count for Meteorite Flux (the total mass of extraterrestrial objects that strike the Earth). This is currently about 10^7 to 10^9 kg/year.The earth is a big molten droplet with a thin skin of solid scum on the surface. Any localised mass pushes the skin lower as it essentially floats on the liquid beneath.
The mass of a large city miniscule compared to a good sized mountain range and if you accept the old story the earth, even with it mountains, is comparably as smooth as a bowling ball.
The mass of a large city miniscule compared to a good sized mountain range and if you accept the old story the earth, even with it mountains, is comparably as smooth as a bowling ball.
schmalex said:
I was pondering this the other evening. Firstly, I’m no physicist and I did start thinking about this after enjoying some wine.
Take somewhere like Manhattan, HK or Dubai. They have got loads of tall heavy buildings in one place. Clearly the materials for those buildings came from somewhere else. Does such a high concentration of weight in a given area (and the removal of a broadly similar amount of weight elsewhere) have an impact on the earth’s position (ie does it rotate slightly under the weight)
If I were to put a football in a bowl of water and press down in one place, the ball would rotate in the direction of the force being applied. Does / can the same happen to the earth?
Not sure if serious....Take somewhere like Manhattan, HK or Dubai. They have got loads of tall heavy buildings in one place. Clearly the materials for those buildings came from somewhere else. Does such a high concentration of weight in a given area (and the removal of a broadly similar amount of weight elsewhere) have an impact on the earth’s position (ie does it rotate slightly under the weight)
If I were to put a football in a bowl of water and press down in one place, the ball would rotate in the direction of the force being applied. Does / can the same happen to the earth?
Have you considered a mountain range is much bigger and heavier than any city. And they also move and change due to plate techtonics and volcanism.
Back an envelope calculation, using some else's estimation of the mass of Manhattan
Mass of the Earth (kg) - 5.972 * (10^24)
Mass of Manhattan (kg) - 1.136 * (10^11)
Mean radius of the Earth (m) - 6371000
I reckon, using point masses, the centre of mass of the two is 1.2 * (10^-7) metres from the centre of mass of the Earth i.e. a tenth of a micron, or the cube root of sod all.
Ayahuasca said:
If the Earth were reduced to the size of a billiard ball, it’s surface - in spite of all the mountains, deep oceans and tall buildings, would be smoother than a billiard ball.
I think I read that on PH, so it must be true.
I saw it on a BBC TV programme about science - I think it is probably trueI think I read that on PH, so it must be true.
To the Op's question - no
What I think is interesting but irrelevant, if you are at the top of a tall building your velocity is higher than if you are at the bottom. (Your angular velocity is the same though).
Is this why its windier at the top of a tall building?
I
The earth is already 'lopsided' - it is an oblate spheroid.
relative to the surface area and mass of, say, the pyrenees, alps, rockies or any other significant geological feature, a building makes no difference whatsoever. Consider the mass of water moving in and out with the tide - again, significantly more mass moving about than digging up some iron to build a tower. The impact is lost in the statistical noise before it can be measured and so can be rearded as though it did not exist.
relative to the surface area and mass of, say, the pyrenees, alps, rockies or any other significant geological feature, a building makes no difference whatsoever. Consider the mass of water moving in and out with the tide - again, significantly more mass moving about than digging up some iron to build a tower. The impact is lost in the statistical noise before it can be measured and so can be rearded as though it did not exist.
glenrobbo said:
It is thought that the Tibetan Plateau is still bouncing back up, along with parts of the Antarctic and the Arctic where the ice sheets are thinning.
The Earth is probably lop-sided anyway, as the land masses are unevenly distributed around the globe.
A few buildings are comparatively insignificant in the Grand Scheme of Things.
Alternatively, too many tall buildings too close to one edge of the Flat Earth could cause it to overbalance and slide off the back of the Giant Turtle.
We should be careful.
With any luck the circumfence should stop that. The Earth is probably lop-sided anyway, as the land masses are unevenly distributed around the globe.
A few buildings are comparatively insignificant in the Grand Scheme of Things.
Alternatively, too many tall buildings too close to one edge of the Flat Earth could cause it to overbalance and slide off the back of the Giant Turtle.
We should be careful.
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