F is the force of attraction between M, object 1 and m, object 2 with a distance of r from each other's center of gravity. Where G is the universal gravitational constant and ~=6.67e-11 Kgm^2/s^2
F=GMm/r^2 - I think you can derive almost every other equation that involves gravity with this little guy.
1.)The natural force of attraction exerted by a celestial body, such as Earth, upon objects at or near its surface, tending to draw them toward the center of the body.
2.)The natural force of attraction between any two massive bodies, which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Gravity exerts its influence on all matter in our universe, every single bit of matter has some (usually so close to zero that it doesnt matter) force acting on it from every other bit of matter.
Gravity is easier to accept than evolution because we can test and observe it first hand, furthermore it's a universal LAW, not a theory. I think Newton derived his gravity laws from his laws of motion, but I might be mistaken. Now.. you get into the quantum theory of gravity and some of the theory of relativity and it's not so cut and dry

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By the way, as time passes, I think we will find more and more evidence to support evolution, and probably a naturalistic explaination of how life originated that can be proven to the extent that the Earth's age and such are, but I think people will still ignore the evidence for at least a few more generations. (can anyone find the run-on sentence?)