what is gravity?

Question

i know gravity is an acctractive force between masses, but why!? why are masses attracted to each other?

Answer 1

What is gravity?
Gravity is a force pulling together all matter (which is anything you can physically touch). The more matter, the more gravity, so things that have a lot of matter such as planets and moons and stars pull more strongly.

Mass is how we measure the amount of matter in something. The more massive something is, the more of a gravitational pull it exerts. As we walk on the surface of the Earth, it pulls on us, and we pull back. But since the Earth is so much more massive than we are, the pull from us is not strong enough to move the Earth, while the pull from the Earth can make us fall flat on our faces.

In addition to depending on the amount of mass, gravity also depends on how far you are from something. This is why we are stuck to the surface of the Earth instead of being pulled off into the Sun, which has many more times the gravity of the Earth.

Answer 2

You have to go back to the big bang for that one.

Super Grand Unified Theories, or Gauge theories postulate that at the moment of the big bang, the universe was infinitely small and infinitely dense and the pressure that had consequently built up caused the big bang, which threw all the energy outward (and therefore all matter).

As energy is neither created nor destroyed, but mereley changes form, the universe began to evolve from this big bang event.

There are four fundemental forces at work in the universe: gravity, strong nuclear, weak and electomagnetic. In the earliest millisseconds after the big bang, all four were as one, but gravity separated from the others first. It is the weakest of the fundemental forces and therefore cn only exert influence on objects of mass. This might sound a bit backward, but think how much energy it takes to keep the subatomic particles together inside an atom (or how much energy is released when they are split - a nuclear explosion) and gravity is the opposite of that - it is a relatively weak attraction between pretty big things.

However, gravity still originates from the initial force that held everything tightly together, so it still has an attractive force, albeit a weak one when compared to the force that holds very small particles together.

Of course, this is just a highbrow way of saying, "they just are", because nobody can tell you why they were all so tightly packed before the big bang...

Answer 3

The real answer is that what you know about gravity already is as much as is recognized by all of science as being true. Which is to say that even most PhD scientists can only tell you about gravity being an inherent attraction between two masses. There are some people attempting to explain the idea better using something called "Super String Theory" This is a field which is growing but is still in its infantile stages. If you want to learn more search for "The Elegant Universe" by Nova. It is a documentary that was shown on PBS.

Answer 4

Physicists don't know the answer to this question. The law of gravity as we know it is based on observations. Some of the closest explanations for the cause of gravity if from Einstein's General Theory of Relativity that relates the warping of space to the distribution of matter and energy (the warping of space is manifested as a gravitational field) and also from variations of string theory. Relativity doesn't explain gravity at the quantum level however. String Theory is the only theory that I have heard of that has actually "predicted" a gravitational force between masses.

Answer 5

The force of gravity is a particular form of energy. Stephen Hawking in “A Brief History of Time,” page 92, paragraph 3, states; “Like light, gravitational waves carry energy away from the objects that emit them.” The equation for this kind of energy is found in the physics trilogy: E = mc2, m = E/c2, and c2 = E/m. The last is that for a field of physical time, or that of a field of gravity.

The reason this force acts as it does is found in its speed and what it is composed of. Of its speed because it acts as a time sink (similar to a heat sink in mechanics) that attracts mass and energy toward accelerating to its speed, in the direction which the lines of gravitational force originated.

The direct answer to your question lies in what mass is composed of. It is composed of electromagnetic energy. This first forms into electrons and these into larger mass. The speed of the electromagnetic energy never decreases in speed even when formed into mass. It overlaps its own frequency by completing an arc of more than 360 degrees and overlaps its own frequency, thus it remains bonded. Gravitational waves in passing through a mass thus composed, creates a physical time potential that were a passing mass to ignore, it would exceed the speed of light.

http://360.yahoo.com/noddarc there are two short writings at this location "Magnetism and Gravity" and "The Problem and Repair of Relativity." Click on "view blog" then on "list view" and scroll down.

Answer 6

Check out Einstein's theory of General Relativity. He reckons that space is curved by the presence of matter. In the case of large bodies such as a star or planet this causes a substantial curvature of the space that the body 'sits' in. Imagine a football lying on a stretched piece of fabric and it makes an indentation in the fabric.
As objects move in a straight line through space (unless a force of some sort is applied), when it meets a curve in space caused by the presence of a large object, it will follow the curve and tend to appear to fall towards the larger object.

Answer 7

http://uk.answers.yahoo.com/question/index;_ylt=AscmjRnHbY1_dVtWvIa3Z7YgBgx.?qid=20070301051200AAy7rLw&show=7#profile-info-38f8f08b4ee720d6af2aaf6540db5648aa

Loads of stuff in the above link, but basically is a molecular attraction directly proportional to the objects mass, it is one of the weakest forces though,when compared to the energy store in molecular bonding and the fact we defeat gravity every second of our lives, compared to controlling a nuclear reaction.

ALSO - it has nothing to do with the earth spinning, everything create a gravitational force, whether it moves or spins or stay perfectly still, a apple in your hand has a gravitational pull, but you wont feel it is too small.

Or in our case, imagine we are zooming past the sun, but its is pulling us towards it and we just keep zooming around and around it instead. These forces are balanced, although we are loosing a very very very small amount of speed over the years.

So us and the other planets are held by our sun and we move around it, other stays hold there planets in place. Imagine spinning a ball on a piece string around with your hand, we are the ball held by the pull of the sun (your hand) , with gravity the string. If gravity stopped, or you cut the string we go shooting off into space !!!

Answer 8

Newton's falling apple is conventional to college toddlers for a protracted time. yet Archimedes's discovery of buoyancy tension is additionally the only. in view that weight and buoyancy tension are canceling out one yet another. Many others weren't being credited for discovery of gravity, yet who comprehend what?

Answer 9

As i know there is no anwser on why, gravitiy exists, the theory of relativity from einstein tries to explain gravity as a result of deformation of space/time, but why gravity, or electricity, or the two core forces, exist, is not known yet. It is difficult enougth to understand how they work, and today i think, not many people anymore think about the why.

Answer 10

gravity is the inherent property of a body by which it is attracted to
to any other body. It is present between all atoms in the universe and follows the inverse square law.