Understanding Gravity

There are many different ways to visualize how gravity functions. However, one of the best way I have found to visualize gravity is with strings and using the center of mass. Gravity is the weakest force of the four fundamental forces, however, it works over an infinite amount of distance. I put this in perspective by assuming every object, especially celestial objects, are connected by a long string— regardless of distance. So, every object, even if it’s at a minuscule scale, is being pulled towards one another. If we think about this in terms of a clump of objects, such as a galaxy, I visualize it more as a tug-of-war between two galaxies. The heavier galaxy is going to win but they both will still be pulled to each other.

The center of mass comes into effect when two massive bodies are close enough together that the force of gravity is strong enough to cause a noticeable physical reaction. If two bodies are approximately the same mass, are connected by an invisible string, and close enough for the force of gravity to cause a noticeable effect, they will begin to orbit each other. Because the two bodies are equal size, neither are winning the tug-of-war so, they will orbit around the middle of the two of them. Likewise, if one of the celestial objects is twice the mass of the other, the larger massed object will have a smaller tighter orbit around the center of mass as the lighter one. If we have a scenario where one object is significantly heavier than the other (such that M>>m) then the heavier object will have such a small and tight orbit that it is nearly undetectable, while the smaller object seems to orbit around the larger one (such as the earth and the sun). There are examples of these as can be seen here. This is the fundamental way that I view gravity.