Why Is There More Mass But Less Gravity At The Equator?

Textbook explanations conveniently disregard this part of the calculation of the surface gravity at the equator. There is more mass between a body and the Earth's center due to the equatorial bulge and yet a lower force of gravitational attraction. This is completely counter-intuitive. Even Brian Cox mentions this anomaly in the TV programme 'What On Earth Is Wrong With Gravity?'. Does anyone agree that this is bizarre?

 

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A Growing Earth Theory hypothesis:

Mass accretion aka meteorite impacts at the biggest possible target on the Earth, i.e it's widest point, the diameter/equator.

However it's not just the equator that shows gravitational anomaly. All impact sites show gravitational anomaly.

How do you find a crater under kilometers of ice? You use gravity sensing satellites, like NASA's two GRACE satellites, which are so sensitive they can measure the gravitational effect of heavy rainfall.

http://www.sciencedaily.com/releases/2006/06/060601174729.htm

Or not...:idea:

 

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Because it is further away from the Earth's centre of mass.

 

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I'm not convinced by this statement. The assumption of a center of mass is a convenient solution for mathematics, but reality is another thing altogether. Your answer does take into account a mechanism for gravity, which is always going to be your downfall.

 

The earth is spinning, so the centripetal acceleration decreases the apparent gravity at the equator the most, and zero at the poles.

 

The Earth's surface is approximated by the equipotential ellipsoid of a rotating, self-gravitating fluid. For such an ellipsoid, the equatorial bulge is at the same potential as the poles, but the force of gravity is related to the rate of change of that potential and as the bulge is further away, the rate of change is smaller and therefore so is the gravity.

 

...which is why NASA built a launch platform on the Florida Peninsula instead of Pennsylvania, and why Russian and Chinese launches use more fuel per ton launched.

 

Partially correct. That the Earth is spinning also makes the Earth's take on the shape of an oblate spheroid.

To elaborate: The Earth's surface is very close to an equipotential surface of the combined gravitational and centripetal (pseudo) forces; the mean sea level is exactly an equipotential surface.

 

I'm suggesting that either positrons, or antimatter in general, or something else is causing gravity because our electrons are clearly negatively charged.

Herndon believes the core is a nuclear reactor however Tassos has said the core is not a heat engine.

Perhaps there is something more mysterious going on as suggested by Owen and Corliss and others.

"The geological and geophysical implications of such Earth expansion are so profound that most geologists and geophysicists shy away from them. In order to fit with the reconstruction that seems to be required, the volume of the Earth was only 51 per cent of its present value, and the surface area 64 per cent of that of the present day, 200 million years ago. Established theory says that the Earth's interior is stable, an inner core of nickel iron surrounded by an outer layer that behaves like a fluid. Perhaps we are completely wrong and the inner core is in some state nobody has yet imagined, a state that is undergoing a transition from a high-density state to a lower density state, and pushing out the crust, the skin of the Earth, as it expands." -- Hugh Owen, geophysicist, 1984

 

Suggesting the core may be made of something completely new and unthought of sounds similar to my theory. It's worth considering for sure.

 

You don't have theory. OIM has pyschoceramics and strawman arguments.

No, it is not.

 

Hardnose cynic.

 

Equators centripedal force makes gravity "feel" slightly less at the equator verse the poles, this also is why the earth bulges at the equator slightly, there is not increase mass in the bulge rather density of the rock has been reduced ever so slightly because it not being crushed down as hard as at the poles.

 

ElecticFetus, this is nonsense. Centrifugal force at the equator would suggest an increase in density of the material, with the lighter matter being pushed towards the poles. The Moon dosen't spin like the Earth, but it also has flattening and a lower surface gravity at the equator. Therefore the centrifugal force argument for the Earth is unvalidated.

 

No the lighter material would be pushed towards the equator, bubbles and balloons fly up not down, so lighter rock would move towards the point of least gravity by simple act of buoyancy. The Moon experiences less gravity at its earthward facing equator because its closer to the earth and thus the earth negates a little of its gravity, this is why it has ancient lava seas on the earth facing side and barely any on the other side.

 

No, no. The centripetal force of the crust reacting against the centrifugal force of the liquid mantle is greater at the equator. The bubbles would migrate away from this high pressure zone to the poles, just like a washing machine in spin.

 

That would be if the centrifugal force was stronger than gravity, which it isn't by a long shot, instead the process is reversed with the lower density going toward the bulge and the high density going towards the poles, because gravity is "weaker" at the bulge, not stronger as would be the case if the earth were in fact a centrifuge.

 

Because gravity increases proportionately to the mass involved, but decreases proportionately to the square of the distance involved. At the equator, there may be more mass between you and the center of the Earth, but there's also more distance, because of the bulging, and the increased distance has a bigger effect than the increased pass.

If you take a planet, and double its mass, but without changing its size, its surface gravity doubles. If you also double its radius at the same time you double the mass, surface gravity is lower than it was before. If you triple its mass and "only" double its size gravity still gets weaker at the surface.

 

It still seems odd. It's like saying that if the Earth is scaled larger, then it's surface gravity is reduced. That's nonsense.