# The Naked Scientists Forum

### Author Topic: Where is gravity greater?  (Read 1946 times)

#### Jon Francis

• Jr. Member
• Posts: 28
##### Where is gravity greater?
« on: 19/08/2010 00:49:11 »
If it was possible to bore a tunnel to the centre of Earth would gravity be stronger there than on the surface of the planet?

#### RD

• Neilep Level Member
• Posts: 8128
• Thanked: 53 times
##### Where is gravity greater?
« Reply #1 on: 19/08/2010 01:31:22 »
At the centre of a truly symmetrical sphere the gravitational forces would cancel out: no net force...

Quote
Isaac Newton proved the shell theorem saying that:

1. A spherically symmetric body affects external objects gravitationally as though all of its mass were concentrated at a point at its centre.
2. If the body is a spherically symmetric shell (i.e. a hollow ball), no gravitational force is exerted by the shell on any object inside, regardless of the object's location within the shell.
3. Inside a solid sphere of constant density the gravitational force varies linearly with distance from the centre, becoming zero at the centre of mass.
http://en.wikipedia.org/wiki/Shell_theorem
« Last Edit: 19/08/2010 01:35:11 by RD »

#### The Naked Scientists Forum

##### Where is gravity greater?
« Reply #1 on: 19/08/2010 01:31:22 »