"Gravity is self-evident"

Viani

I thought everything needed evidence. What supporting evidence exists to prove that Gravity exists?

First one to answer wins a Pinkie Point.

Sredni Vashtar

Some scientists did an experiment over a century ago involving two enormous, extremely heavy metal spheres suspended in an empty tower in the middle of an open field. Observing them over a fairly long period of time, the scientists observed that the spheres pulled toward each other very, very slowly, to a very tiny degree. This and several other studies ultimately proved that all objects have some degree of gravity, but that only very massive objects have enough gravity to effect changes in their environments in a noticeable way.

Viani

+10 PP for also pointing me in the right direction

Odradek

IJBM: People confusing the force that gives weight to objects with "things falling down".

One is the easily observable result of the other hard to observe thing.

Sredni Vashtar

Yeah, yeah, weight is not mass, et cetera, et cetera. I know that. But mass is the propagator of gravity, so getting into the minutiae of it seems inappropriate.

Bee

^^^^ Heck of a lot earlier than that.  Newton's law of universal gravitation was laid out since the late 1600's.

About a century later, the gravitational constant G was measured by Cavendish using a torsion balance -- basically, a hanging beam with lead weights on either end, with the gravitational force exerted on one of the weights calculated by measuring the balance's twist angle against the torsion constant of the wire it hung from.

EDIT: It was 1798.

Sredni Vashtar

I was aware of Newton's law, but I could not recall when the Cavendish experiment was conducted. I assumed that it was in the late 18th or early 19th century, so I just said over a century and left it at that.

Previous Calica

This isn't gravity, but one of the most interesting scientific stories to me is that of stellar aberration; extensive data sets were collected to detect parallax, one of the consequences of heliocentrism, but instead found motion roughly 90 degrees off; it turns out that this is an effect of the speed of light and the motion of the earth compared to the Sun and the rest of the stars, so they found evidence of heliocentrism in a completely unexpected way.