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View Full Version : New Map Of Gravity On Earth.

HerpsNAO
07-14-2010, 07:37 PM
Note the gravity on Iceland where there is tons of volcanic activity and the mid atlantic ridge.

http://gajitz.com/getting-kind-of-heavy-worlds-first-map-of-earths-gravity/

moosecakes4all
07-14-2010, 07:41 PM
Good post! Thanks for sharing that.

07-14-2010, 08:08 PM
Very neat stuff, nice post!

HerpsNAO
07-14-2010, 08:52 PM
bamp

Hardcore_D00d
07-14-2010, 08:57 PM
brb training in 100x gravity like goku

AC33
07-14-2010, 08:58 PM
Wonder how much difference we're talking about here in terms of something like the weight of an object. Would a 100lb object in Iceland for example, weigh less in South India? If so by how much? Saw this map in a BBC article before and couldn't really get much out of it. Any misc physicists care to put there 2 cents in?

HerpsNAO
07-15-2010, 09:32 AM
Wonder how much difference we're talking about here in terms of something like the weight of an object. Would a 100lb object in Iceland for example, weigh less in South India? If so by how much? Saw this map in a BBC article before and couldn't really get much out of it. Any misc physicists care to put there 2 cents in?

No clue.

V1984
07-15-2010, 09:50 AM
No clue.

Acceleration due to gravity (on average on Earth) is 9.81 m/s. The acceleration due to gravity will be inversely proportional to the square of the distance between the center of the earth and an object. This means that the higher you go, the weaker gravity becomes. If object A is twice as far from the center of the Earth as object B, object A will only experience a quarter of the gravity of object B. The gravity on Mount Everest, for example, would be weaker than the gravity at sea level. The gravity on the International Space Station (which is in the Thermosphere, way above the Earth) has a much lower acceleration due to gravity. Basically, the gravitational pull you'll experience is stronger the closer you are to the Earth's center of mass. I'm no expert, so someone can correct me if I'm wrong, but this is the way I understand it.

telega C 33
07-15-2010, 10:14 AM
brb going to india so i can dunk

elephino
07-15-2010, 10:19 AM
Yeah, apparently, you'd lose almost 1% of your weight due to Gravity fluctuations between England and India. So you could lose a whopping two pounds if you weighed 200.

Your mass, on the other hand, would remain the same :)

reyalp
07-15-2010, 10:19 AM
I'm no expert, so someone can correct me if I'm wrong, but this is the way I understand it.

Why just the center of the earth? Wouldn't there be pull from the mass past the center?

V1984
07-15-2010, 10:33 AM
Why just the center of the earth? Wouldn't there be pull from the mass past the center?

That's just one of the properties of gravitation; you use the center of mass of an object. The center of mass may not be in the exact physical center of the object. To get the force of attraction between two objects, you'd use F = G(m1 + m2) / r^2.

F is the gravitational force, m1 is mass 1, m2 is mass2, r is the radius between the separation of the two masses.

http://en.wikipedia.org/wiki/Center_of_mass

I also don't want to make this more complicated, but this is all using Newton's law of universal gravitation, which we have found to be incorrect. Newton's law of universal gravitation was replaced by general relativity, established in the early 1900's by Einstein.

Discov3ry
07-15-2010, 12:15 PM
Physics brahs, why is the unit in the legend expressed as 'metres' (meters)?

Moh7
07-15-2010, 12:21 PM
Physics brahs, why is the unit in the legend expressed as 'metres' (meters)?

probably cause its a french graph or something

edit: wait... my physics teacher said something about the spelling but i forgot..

Discov3ry
07-15-2010, 12:51 PM
probably cause its a french graph or something

edit: wait... my physics teacher said something about the spelling but i forgot..

The spelling makes sense, if its French, then they probably used British english 'metres' instead of American english 'meters' but why meters damnit!

I wonder if two identical humans who lived in Iceland and India all their lives were to have different body growth: bone density, height, muscles strenght etc due to difference in gravity?

4nicate
07-15-2010, 12:58 PM
brb training in 100x gravity like goku

Exactly what I was thinking...

xToXiCxk23
07-15-2010, 01:07 PM
brb starting a business that garauntees weight loss while traveling the world :)

V1984
07-15-2010, 01:29 PM
The spelling makes sense, if its French, then they probably used British english 'metres' instead of American english 'meters' but why meters damnit!

I wonder if two identical humans who lived in Iceland and India all their lives were to have different body growth: bone density, height, muscles strenght etc due to difference in gravity?

Well, the difference in gravitational pull between sea level and a mountain is there, but is very small: "... gravity does indeed change with altitude. The gravitational force above the Earth's surface is proportional to 1/R2, where R is your distance from the center of the Earth. The radius of the Earth at the equator is 6,378 kilometers, so let's say you were on a mountain at the equator that was 5 kilometers high (around 16,400 feet). You would then be 6,383 kilometers from the Earth's center, and the gravitational force would have decreased by a factor of (6,378 / 6,383)2 = 0.9984. So the difference is less than 0.2%."

http://curious.astro.cornell.edu/question.php?number=465