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Poll

What do you think about Earth gravitation anomaly?

Simple, it can be answered.
6 (75%)
It doesn't make sense.
0 (0%)
We need a different gravity theory.
1 (12.5%)
What is it?
1 (12.5%)

Total Members Voted: 8

Voting closed: 24/03/2012 15:32:55

Author Topic: Earth Gravity anomaly  (Read 16235 times)

Offline Sprool

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Re: Earth Gravity anomaly
« Reply #25 on: 07/03/2012 12:24:28 »
All the gravitational anomolies I can see are adequately explained by the differnces in density of the underlying rocks, into the deeper mantle and in the crustal region. That is my 2c worth - hotspots exist in the crust due to the underlying geology and laying rise to plate tectonics. Together with this are the differnces in mass and density of the underlying rocks since the crust and mantle are not homogeneous.
« Last Edit: 07/03/2012 12:27:12 by Sprool »
 

Offline Phractality

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Re: Earth Gravity anomaly
« Reply #26 on: 08/03/2012 04:32:45 »
Hot stuff rises relative to the same stuff which is colder. That's why you get convection currents when heating a pot of water. If you have cold oil on top of the hot water, the oil doesn't sink because, even when cold, it's still less dense than hot water.

The mass that is gained by heating material is a tiny fraction of the mass the material would have at absolute zero. The material expands millions of times more than the increase of mass.

The continental plates are floating higher on the mantle than the oceanic plates because the continents are less dense. Mountains also rise higher if they are made of less dense rock. So higher elevations don't necessarily mean more mass below you; it may just mean that the continental plate material is lighter and thicker.

The Earth may have originally solidified more uniformly, with all the dense stuff in the middle and only light stuff near the surface. Later, it is widely believed that a Mars-size planet collided with Earth, shattering it into millions of pieces. The pieces then recombined to form today's Earth and the moon. That cataclysm would have ended up with some denser parts near the surface and some lighter parts deep within.
 

Offline Sprool

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Re: Earth Gravity anomaly
« Reply #27 on: 08/03/2012 12:14:37 »
THere is also geological theory of salt domes - large chambers of less dense rock bouyant in the mantle causing uplift above them, that can explain some apparent disparities between mountain masses and local gravitational field. Sometimes the field is stronger than average, sometimes less, depending on the local geology.
 

The Naked Scientists Forum

Re: Earth Gravity anomaly
« Reply #27 on: 08/03/2012 12:14:37 »

 

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