Is gravity a force or........?

Question

Is gravity a force or is it the pressure of the atmosphere that keeps us on the ground? If it is a force ,how is it created?

Answer 1

While it's commonly banded about as a force, the problem with the currently 'accepted' standard model is that forces are mediated by exchange particles. For three of the four fundamental forces (the strong interactions, weak interactions and electromagnetic interactions) these exchange particles have been observed (or at least their effects have been), in the gluon (Strong) photon (electromag) and W and Z bosons (weak interactions). However, the hypothesized particle for gravity, the imaginitively titled 'graviton' has yet to be observed.

Therefore it is currently a contentious issue wether gravity is a force or not, despite the obvious force of attraction between bodies with mass.

Answer 2

Gravity is a force and exists where ever matter exists. We have a mass and the earth also has a mass. So, we attract each other and the force is governed by the formula,

F = M1 X M2 / r^2 where M1 and M2 are the masses of the two objects and r is the distance between their centres of gravity. Since the mass of the earth is very large compared to our own mass, the gravitational force exerted by us on the earth by us is negligible and we feel the force exerted on us by the earth. Atmospheric pressure has no connection with gravity. Even moon has gravity though much less than earth (1/6th) though moon has no atmosphere.

Answer 3

According to Newton's Law of Gravitation, every object in the universe exerts force in every other object by virtue of its mass. This force is called gravitational force. Thus all objects having mass exert and experience gravitational force.

Now to your second question. The atmosphere that you see around us is a result of intense gravitational force of the earth. The gravitational force pulls the molecules of gases towards the earth. Had there been no gravity then all the gases in the atmosphere would have escaped in the universe. Also hydrogen is the most abundant gas in the universe. It is just because hydrogen is the lightest gas and so can easily escape from gravitational field of all massive bodies.

So it is ultimately the gravitational pull that is keeping us on the earth...

Answer 4

Good answer from The One...

Also consider that gravity is actually a very weak force. Compare gravitational force to magnetic force - you can take a magnet off of your fridge, hold it above a pin, and overcome the Earth's gravitational pull down on the pin. Gravity needs incredible mass over a large scale.

Answer 5

The view of Einstein's General Relativity is that gravity is the curvature of space-time that occurs in the presence of matter and/or energy. Gravity is not itself a force but the application of force is one of the effects of gravity. Gravity holds astronauts in orbit but they feel no force. The space station is orbiting the earth but no force is required to hold it in orbit. It is coasting in a straight line through curved space-time. Jump out of an airplane and you feel no force during freefall (except air resistance). Force is not applied until you hit the deck.

Think of a truck. A truck is not a force but if it runs you over you will have force applied to you. Don't try this at home.

Answer 6

Hi,

gravity, as the other answerers have stated, is a force. Studied by Sir Isaac Newton, who (traditionally) was struck (quite literally) by a thought after an apple reputedly fell on his head. He wondered why anything should fall...

...He studied for many years before coming up with his 'Laws of motion' theory.

Atmosphere has nothing to do with gravity, nor does pressure. There is an attraction (assumed to be magnetic) between any object and surrounding objects.

In larger objects, like stars, planets and moons, etc. this attraction can be measured and it is this attraction that stops our moon from flying off into space as it 'whizzes' round us, and stops us from doing the same as we 'whizz' round our sun.

Scientists are able to measure how some bodies are moving apart, or are moving closer to each other as a result of other bodies exerting their own gravitational pull on them. If you imagine our own solar system with a number of flying objects circling the central sun (and remaining relatively stable) then imagine that there are countless other, much larger, stars exerting 'pull' which affects our own sun's gravity, and ours. The problem becomes a huge mathmatical problem that only computers can begin to handle.

Good question, though.

BobSpain

Answer 7

Gravity is not a 'force' in the conventional sense. Think of it more as an effect that we experience when space time is warped by the presence of a massive lump of matter, eg a planet

Answer 8

It is the gravitational force and not the atmospheric pressure that keeps us on the ground. As light is formed by photons ,similarly, gravity is formed by gravitones.

Answer 9

It is a force, the weight of the atmosphere does add a little to the effect, i suppose.

There are oodles of scientists around the world trying to find out how gravity works, we don't really understand it yet.

We know a lot about it and can accurately predict it but we can't quite pin the tail on the gravitational donkey as to why it happens. Current theory is that it is the bi-product of the Earth existing in space-time.

If the Earth wasn't there then the space-time would be even and 'un-stressed'. If you then squeeze a planey into that space then the space-time has to be forced out of the way, squeezing space-time tightly around the planet. This squeezing of space-time is thought to result in gravity.

Answer 10

Ever thing in this world has a property of gravitational force and this force is directly proportional to the mass of the body.

So larger is the mass, larger is the gravitational pull by that body.

It means that however small the size of anything , will have a gravitational pull of its own.

Like when you take a jump, earth pulls you towards itself and you pull earth towards yourself !!!!
But as your mass is much much less than that of earth, the pull by your body will be negligible.......