Gravity

Gravitation is a natural phenomenon by which objects with mass attract one another.<ref name="Does Gravity Travel at the Speed of Light?">Does Gravity Travel at the Speed of Light?, UCR Mathematics. 1998. Retrieved 3 July 2008</ref> In everyday life, gravitation is most commonly thought of as the agency which lends weight to objects with mass. 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.

Modern physics describes gravitation using the general theory of relativity. Newton's law of universal gravitation provides an excellent approximation for most calculations.

The terms gravitation and gravity are mostly interchangeable in everyday use, but a distinction may be made in scientific usage. "Gravitation" is a general term describing the phenomenon responsible for keeping the Earth and the other planets in their orbits around the Sun; for keeping the Moon in its orbit around the Earth, for the formation of tides; for convection (by which hot fluids rise); for heating the interiors of forming stars and planets to very high temperatures; and for various other phenomena that we observe. "Gravity", on the other hand, is described as the theoretical force responsible for the apparent attraction between a mass and the Earth.<ref>http://alex.edfac.usyd.edu.au/Methods/Science/studentwork/MassoftheEarth/gravitationandgravity.htm</ref> In general relativity, gravitation is defined as the curvature of spacetime which governs the motion of inertial objects.

Notes:

I can't imagine anything more important that.

External Links:

• http://science.howstuffworks.com/question232.htm - howstuffworks!
• http://www.geocities.com/Paris/6502/impact.html - java gravity simulator