# Does the gravitational field of the Earth emanate from the surface of the Earth or from its center?

poldi2

Gravity is created by the entire mass of the planet, it behaves as though that mass was concentrated at the center.

Dale-E

Gravity is easily experienced, yet difficult to satisfactorily understand. With this Y!A,, 2 of your words are within my skill level to explain. 1. "field" refers to rows of ridges and valleys. Gravity, though slightly variable over the earth, does not present itself as a field to us. 2. "emanate" has to do with emergence. For there to be an emergence, there has to be a flow. That is where it gets sticky, ( no charge for the chuckle ). Gravity is part of us, not just out of the terrestrial ball. We are part of it.

Bill-M

Gravity emanates from all of the Earth's Mass. Everywhere.

Zardoz

From each individual point of mass. The net effect is toward Earth's center of mass — which is a bit tautological. You're holding onto an elephant's tail with one hand and a rhino's tail with the other. A shot is fired spooking the elephant and rhino into running away. The elephant is running to NNE with a 4 ton force. The rhino runs NWbyW with a 2 ton force. Question: What is the net force and direction? Answer: Elephino. (4.36 tons; N 0°0'6.05" E)

busterwasmycat

all mass attracts other mass. the center of the earth is only the effective net point of concentration of the attraction. Mass on the near side is closer so attracts more strongly than the mass on the far side at the same distance from center, so the one, added to the other, is the same as two times the center. the center is the "average" point for all when taken together. Same idea as add all the integers from 1 to 100 (1+2+3...+98+99+100) can be figured out by multiplying the biggest plus the smallest (100+1) times half the amount of numbers (50). This does not mean that 1,2,3, 48, 72, and 100 do not have different values. It means that you can look at the sum through the average. All those different values are not 50.5(=(100+1)/2), even though you can pretend that to make the calculation easier. When we calculate force using the center of mass, we are "pretending" that each value is the same as the average (because it is simpler). They are not, though. They just act that way.

Gray Bold

Dynamo theory suggests that convection in the outer core, combined with the Coriolis effect, gives rise to Earth's magnetic field. The solid inner core is too hot to hold a permanent magnetic field but probably acts to stabilize the magnetic field generated by the liquid outer core. The average magnetic field strength in Earth's outer core is estimated to be 25 Gauss (2.5 mT), 50 times stronger than the magnetic field at the surface.

Armchair Goddess #1

Based upon my mom's lettuce crisper from the 1950s that one swings in a circle to throw off the water, and on the principle of swinging a bucket rapidly with water in it that remains in the bucket, and also on the principle behind the carnival ride that is called the "Graviton," one could perhaps assume the gravitational field of the spinning (and also orbiting) planet Earth is created by a little thing called "centrifugal force" (and that generally mean a center (centrifugal) force, but you would also have to factor in the resistance that impacts as the spin occurs. The word "emanate" would make the answer "from its center."

billrussell42

it "emanates" from all of it. Each piece of earth, each atom, has a gravitational force, attraction, on every other atom in the universe. The forces of each atom of the earth add up to form the gravitational attraction we all feel. To something on the surface or higher, it appears like the force comes from the center, but that is just the vector sum of all the forces from all the atoms. If you dig down below the surface, you will find that the force of gravity goes down, as you get cancelation from the portion above you. And, it is the force each atom has on all others that holds the earth together and forms it into a sphere (or close to one).

Atarah Derek

Where is YOUR center of gravity located? At the center of your mass, correct? Why would a big marble floating in space be any different?