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An interesting little science fact

H

hjo3

Diamond Member
Did you know the force of gravity actually increases as you move deeper into the Earth up to a certain point? 3,550 miles from the core it's 1.02 Gs; 2,150 miles from the core it's 1.09 Gs. Wacky, huh?
 
yes i did... F = G m1m2/ R^2, where G = constant (don't remember value), m1 = mass 1, m2 = mass 2, r = distance between them
 
Originally posted by: tfcmasta97
... you expected what now?
Click to expand...
Most people would expect gravity to decrease as you move towards the center of the Earth... after all, at the core, it's effectively 0 G (or close to it).
 
Originally posted by: Fenixgoon
yes i did... F = G m1m2/ R^2, where G = constant (don't remember value), m1 = mass 1, m2 = mass 2, r = distance between them
Click to expand...


BZZZZZTT! Nice try, but no. He's talking about going INSIDE the earth.
 
Originally posted by: hjo3
Originally posted by: tfcmasta97
... you expected what now?
Click to expand...
Most people would expect gravity to decrease as you move towards the center of the Earth... after all, at the core, it's effectively 0 G (or close to it).
Click to expand...

Actually.. if you assume that the earth is a perfect sphere, there is 0 net force anywhere INSIDE the earth. Using F= Gm1m2/R^2, you gotta take into account that there's mass on all sides of you. Turns out that in a sphere with uniform mass distribution the mass1/R1^2 on one side perfectly counteracts the mass2/R2^2 on the other side of any point of reference within the sphere. Obviously, since the earth is not a perfectly uniform sphere (core, mantle, crust), this will not hold true.
 
Originally posted by: Random Variable
At some point the force of gravity will begin to decrease as you dig deeper because m1 will keep getting smaller and smaller.
Click to expand...

No. In "theory", once you're inside the "sphere" of earth, net gravitational force is 0. But as I mentioned in my previous post, since the earth is not a uniform sphere, this will not technically hold true. However, gravitational force does not uniformly decrease the further you go in. It's just not how physics works.
 
Actually, the REAL effect here is density. The earths core is far more dense, and thus gravitates more strongly, than the surounding rock. Thus, closer to the core, you get the greater density gravatational field, due to closeness, however, at some point, the gravity lost due to having less total mass counteracts that.
 
Originally posted by: Tick
Actually, the REAL effect here is density. The earths core is far more dense, and thus gravitates more strongly, than the surounding rock. Thus, closer to the core, you get the greater density gravatational field, due to closeness, however, at some point, the gravity lost due to having less total mass counteracts that.
Click to expand...

This is not to say that any other posts were wrong, just that they aren't relevant in this instance.
 
Originally posted by: Powermoloch
duh...of course...the more closer you get to the center...the higher it is...isn't it? same as for pressure and temperature.
Click to expand...
Pressure and temperature, sure -- gravity's different. 750 miles from the core it's only 0.45 Gs, for example.
 
Originally posted by: Connoisseur
Originally posted by: hjo3
Originally posted by: tfcmasta97
... you expected what now?
Click to expand...
Most people would expect gravity to decrease as you move towards the center of the Earth... after all, at the core, it's effectively 0 G (or close to it).
Click to expand...

Actually.. if you assume that the earth is a perfect sphere, there is 0 net force anywhere INSIDE the earth. Using F= Gm1m2/R^2, you gotta take into account that there's mass on all sides of you. Turns out that in a sphere with uniform mass distribution the mass1/R1^2 on one side perfectly counteracts the mass2/R2^2 on the other side of any point of reference within the sphere. Obviously, since the earth is not a perfectly uniform sphere (core, mantle, crust), this will not hold true.
Click to expand...


You are 100% wrong. There is force inside of a constant density sphere. Do the calculus yourself. It is only inside a spherical SHELL that there is no force.
 
Originally posted by: KillerCharlie
Originally posted by: Connoisseur
Originally posted by: hjo3
Originally posted by: tfcmasta97
... you expected what now?
Click to expand...
Most people would expect gravity to decrease as you move towards the center of the Earth... after all, at the core, it's effectively 0 G (or close to it).
Click to expand...

Actually.. if you assume that the earth is a perfect sphere, there is 0 net force anywhere INSIDE the earth. Using F= Gm1m2/R^2, you gotta take into account that there's mass on all sides of you. Turns out that in a sphere with uniform mass distribution the mass1/R1^2 on one side perfectly counteracts the mass2/R2^2 on the other side of any point of reference within the sphere. Obviously, since the earth is not a perfectly uniform sphere (core, mantle, crust), this will not hold true.
Click to expand...


You are 100% wrong. There is force inside of a constant density sphere. Do the calculus yourself. It is only inside a spherical SHELL that there is no force.
Click to expand...

I shoulda caught that. GJ.
 
Originally posted by: Connoisseur
Originally posted by: Random Variable
At some point the force of gravity will begin to decrease as you dig deeper because m1 will keep getting smaller and smaller.
Click to expand...

No. In "theory", once you're inside the "sphere" of earth, net gravitational force is 0. But as I mentioned in my previous post, since the earth is not a uniform sphere, this will not technically hold true. However, gravitational force does not uniformly decrease the further you go in. It's just not how physics works.
Click to expand...

I believe that principle applies to a hollow sphere.
 
Originally posted by: Tick
Originally posted by: Tick
Actually, the REAL effect here is density. The earths core is far more dense, and thus gravitates more strongly, than the surounding rock. Thus, closer to the core, you get the greater density gravatational field, due to closeness, however, at some point, the gravity lost due to having less total mass counteracts that.
Click to expand...

This is not to say that any other posts were wrong, just that they aren't relevant in this instance.
Click to expand...

Oh, come on... some of the other posts are wrong!
 
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