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Is the rate of gravity in Kansas the same as it is in Pakistan? Is it different at the equator than say in anartica? Is gravity the same in the marianas trench or on kilamanjaro?
Also has it always been constant over the millions of years? Is/has there been a trend?
Is there anyway to measure this other than taking emperical observations?
I have no idea but was pondering the question, forgive me I'm an international studies undergrad
No, gravitational pull is not uniform across the earth.
first issue, you have mountains and valleys that distort gravitational pull based on your distance to the earth's center.
second issue, even if the earth were a smooth (equipotential) geoid, then you still have different densities of the earth's composition that distort gravitational pull.
third issue, even using a theoretical "smooth earth" that was of uniform density, the earth is still shaped like a geoid, not a sphere, so your distance to the center varies based on your position on the geoid.
Gravity depends on mass and there are extremely miniscule differences at different geographic points on the Earth's surface; as explained by the previous poster. If mass stays constant, than gravity does too; unless mass is added or subtracted from the system.
The Earth's mass has changed through time, so therefore, so has it's gravitational "pull". This can result from collisions and accretions from other celestial bodies etcetera; as well as any material being ejected from any collisions.
I can not figure out what your questions have to do with International studies ?
Back to your questions, only the last one I can answer.
Q: will it continue ?
A : Who knows !
I thought the question could be a possible no brainer, so I wanted to indicate that what i study is not a hard science. I wish i had a talent for astronomy or physics though! Back to the question at hand...
So it is fairly uniform and there are miniscule differences. Has a determined scientist or organization gone out and measured these differences? I'm just curious or is all that there is to be said and done about gravity already been dealt with?
LOL...gravity is the LEAST understood of the 4 fundamental forces...it is "carried" by a hypothetical particle called a graviton, which has yet to be observed. However, as mentioned we understand most of the force and the miniscule differences that were discussed are of NO consequence in calculations involving the Earth/Moon system...the solar system, galactic interactions etc.
To answer another poster...gravity is here to stay...it is a FUNDAMENTAL FORCE...it will be around until the "end of time and/or the end of the universe/multiverse"...so I'd say it's gonna be here forever, since universes are constantly created and gravity will be a force in many/most of them.
IF we understood GRAVITY as well as the WEAK; STRONG and ELECTROMAGNETIC FORCES...we would have the elusive THEORY OF EVERYTHING and the world would be a COMPLETELY CHANGED and technologically different place...think anti-gravity...floating cities etc. WE DO NOT understand it to that extent....YET.
To the OP...PLEASE read ALL the provided links...otherwise you will NOT understand what we are talking about. ;-) AND HARRY CHICKPEA...WE do NOT understand GRAVITY NEARLY AS WELL, as the 3 OTHER FUNDAMENTAL FORCES; otherwise as mentioned, we would be FAR MORE TECHNOLOGICALLY ADVANCED by having a THEORY OF EVERYTHING! WE still have a LOT to learn! ;-)
Last edited by PITTSTON2SARASOTA; 03-17-2010 at 08:04 PM..
For 20 years my career's primary function was to accurately provide Latitude and Longitude data; to a mobile satellite launch platform. One of the many things that we monitored and mapped was the gravity fields.We have tried to form a computer map of the earth to describe it's geoid shape, and from that math-model to determine where the center of gravity should be; but it never is. We have maps called: Vertical Deflections, which describe the North-South deflection and the East-West deflection, or how far away from the 'center-of-gravity' the local gravity really is.
When you travel up, to the surface of the water, the water appears to be flat and level with the horizon. But it is an illusion.
Anywhere on the earth's crust that lies a deposit of some extra heavy mass, there will be a local gravity vortex. Stuff will be drawn toward that spot. The surface of the oceans will build up a lump over that spot.
If you were sailing along approaching that lump, you would still experience 'vertical' and looking around you would still see that your horizon is still at approx 90degrees out there in all directions. But really you would be climbing a slope up onto that lump.
Then consider that the earth's crust is thin and fragmented. It floats on top of a liquid mass. The liquid mass is spinning.
A drop of water falling through the air will form itself into a shape, as it fights with the air. Stop it from falling and it will form a different shape. If the only gravity it felt was from it's own mass, then it would be a sphere. Now spin that liquid mass, centrifugal force alone will draw out the equator and squat the sphere out to form a geoid. Give it a fragmented crust and it is still a spinning liquid mass.
The liquid inside the earth is likely not a pure element, but a mixture of things. Some of those things are heavier, they will have more mass, more gravity. So as this liquid mass is spinning there will be globs of heavier material floating in there, which will effect the gravity that we experience up on the fragmented crust.
I'll go along with the idea that it is not as well understood as other forces, but IMO time is equally, if not less understood. The OP question didn't appear to be about the more theoretical aspects, but more about gravity in relationship with earth sciences, hence the flip answer. Interesting info in the thread though.
There is a common illusion of gravity; which is that I can 'feel' my local vertical, I can point 'down' and I can say that in that direction is the center of the planet. In doing so I have defined a vector pointing 'down'.
You can do likewise, in fact millions of us all around the planet can do this, each of us defining our own local vertical vector pointing 'down', and we can all assume that all of these vectors will point toward a mutual spot somewhere.
The idea that all of these vectors should all be pointing at the same spot, creates the illusion.
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