First, no one predicts gravity will be someday the most important force in the universe. In fact, of the four fundamental forces, gravity is by far the weakest by orders of magnitude. There is nothing we know of that will change that. EM force is the second strongest, second only to the strong atomic force, and it's about 10^35 times stronger than gravity. [See source.]
EM and gravity are both force fields that behave like f = k/R^2, which means both forces (f) diminish according the 1/R^2 which is the distance between two sources of the force field. k is the proportionality constant. This means, for example, both EM and gravity forces will diminish to 1/4 their initial value if the distance between the two sources is doubled.
They are also similar in that both fields have infinite range and travel at the speed of light. Thus, if the Sun were to suddenly disappear, we'd see the sunlight go out the same time its pull of gavity on Earth disappears. Since R = 93 million miles and c = 186,000 mps, the time to snuff out Earth after the Sun disappears would be t = R/c = 93 X 10^6/186 X 10^3 = .5 X 10^3 seconds later. 500 seconds is not quite 9 minutes.
They differ in that electrical charges create the EM force field and masses create the gravitational force field. Even so, both fields diminish by the inverse of the square of the distances between the sources.
And of course they differ in that EM forces are carried by photons and gravitational forces might be carried by gravitons. But no one has observed a graviton to date; so it's still a hypothesis. Finally they differ in that EM forces can be attractive or repulsive; while gravitational forces are strictly attractive.
2007-12-12 14:04:05
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answer #1
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answered by oldprof 7
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Because they are both forces. On Earth, electromagnetism is a far more 'powerful' force than gravity.
Some predict that as the universe begins to contract - after it's done expanding from the big bang - that gravity will become the most important force in the universe
2007-12-12 13:36:54
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answer #3
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answered by massassaugi 1
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