e=mc2

[Taylor Norris]

Re: e=mc2

Gravity doesn't move, it moves things.

Right?

http://en.wikipedia.org/wiki/Gravity

Gravitation is a natural phenomenon by which objects with mass attract one another[1]. In everyday life, gravitation is most commonly thought of as the agency which lends weight to any object. Gravitation compels dispersed matter to coalesce, thus it accounts for the very existence of the Earth, the Sun, and most of the macroscopic objects in the universe.

[day_for_night]

Re: e=mc2

Gravity doesn't move, it moves things.

Right?

well, its like you have a bed sheet thats pulled tight on all sides. and then you drop a couple marbles on the sheets, one representing the sun, one the earth.

each would create their own depression in the sheet, representing their amount of mass. the suns would be exponentially 'deeper' than the earths, as its way bigger.

in kamals example, he asks what would happen if you instantly took the marble representing the sun off the sheet (ie. the sun instantly no longer existed)...you would think the earth, which is held in place by the sun's gravity, would instantly go spinning off its orbit. but it wouldn't, it would take approximately 8 minutes before we would know the sun was no longer there from a gravitational perspective, because thats how long it takes light to reach earth...ie. gravity can't be 'faster' than light. (even though it doesn't move).


edit: read here... http://en.wikipedia.org/wiki/Speed_of_gravity