# Q & A: Magnetism and gravity.

Q:
What are the two similarites between gravitational force and magnetic force? thank you.
- samuel Yip (age 12)
singapore
A:
Just about the only thing that you can say in a general way is that magnetism and gravity are similar to each other in that the attraction between two objects gets usually stronger as the distance between them gets smaller.

The gravitational force depends on the masses of the two objects, getting bigger as the masses get bigger. The magnetic force is a bit trickier: it depends on the details of what the atoms inside the material are doing, what their charges are, how fast they are moving etc.

(published on 10/22/2007)

## Follow-Up #1: What is gravity?

Q:
So no one really knows what gravity is? Other than the mass thing. Is there anymore scientific data the actually speculates what the true forces of gravity are? If gravity is a force, then there should be a way to counteract that force. If you counteract it then you can use it. I just can't help thinking that overcoming gravity will set us free.
- Ted (age 20)
Gastonia, NC US
A:

Words like "what gravity is" are very hard to pin down. We have very precise mathematical descriptions of gravity. Newton's description of it as a force caused by any mass works pretty well for many purposes. The modern theory, general relativity, treats gravity as a distortion of spacetime caused by both mass and momentum. It gives very precise and accurate predictions for all sorts of tests. We don't have some deeper knowledge of what other forces or anything else "really is".

I'm not sure what you mean by "counteracting" gravity. We sort of counteract it all the time. For example, if there was just gravity around I'd start falling quickly toward the middle of the earth. Thanks to other forces, I don't.

Mike W.

(published on 07/29/2013)