Does something have to be moving in order to have gravity?

Question

i just wanna know

Answer 1

No, it just has to have mass. It doesn't have to be moving.

Answer 2

The problem with living in the universe that we do is it's impossible for us to tell if something isolated in the middle of nowhere is actually moving. We gauge whether or not we are moving, relative to another object.

While I'm sitting here typing this I'm not going anywhere relative to the room I'm in, but I'm actually on a planet hurling around the sun, which is hurling around the galaxy, which is hurling around something else at amazing speeds.

We know that gravity is related to the mass of an object and for all practical purposes in a general physics course, the object will have the same amount of gravity whether it's moving relative to something or not.

You may have heard that an object with mass can't reach light speed because the faster it goes, it's mass increases and so it'd take an infinite amount of energy to reach light speed. This increase in mass is often reffered to as relativistic mass...in actuallity, the mass doesn't actually increase but the momentum changes. Then we get into arguments about the speed of gravity.

So I'll say, no, to the best of our definition of moving, something does not have to be moving to have gravity.

Answer 3

In order to have gravity? Gravity is everywhere on Earth. You can't go to Starbucks and order a Venti Gravity Mocha. Gravity is like the air we breath. It's there. So your answer is no.

Answer 4

People get confused about this b/c they hear "If the earth stopped spinning we'd all fly off".

a) mass creates gravity not spin.
b) We would NOT fly off the earth if it stopped. You need to go 17,000 mph to leave earth and the earth is spinning about 700 mph (where I am anyway, it's about 1000 mph at the equator) So we would all just fly to the east very quickly (and probably die) until we ground to a halt.
c) If the earth spun fast enough, it would counteract gravity and we WOULD fly off. Just like a merry-go-round at the park.

Answer 5

How could you tell it was moving, if there's no absolute frame of reference.

Mass creates gravity, and gravity is equivalent to acceleration for most practical purposes.

Answer 6

Gravity is another way of expressing the gravitational force. This force exists in all objects that have MASS. It is not dependent on motion.

Answer 7

maybe he means the earth. the earth is spinning at 67,000 mph and we are all moving with it. i'm interested too, does the earth's spinning cause the gravity ?

Answer 8

Does your car float away when you arent using it?

Answer 9

umm... no... is your computer floating away right now??

Answer 10

No it doesn't.