Foster Running Economy Sports Med 2007

Gravity is a fundamental force of nature that causes objects with mass or energy to be attracted to one another. It is responsible for phenomena such as the falling of objects to Earth, the orbits of planets around the Sun, and the formation of galaxies. Sir Isaac Newton first described gravity mathematically with his Law of Universal Gravitation, stating that the attractive force (F) between two objects is directly proportional to the product of their masses (m1 and m2) and inversely proportional to the square of the distance (r) between their centers, represented by the formula:

F = G \frac{m1 m2}{r^2}

where G is the gravitational constant (6.674 \times 10^{-11} N(m/kg)^2). Later, Albert Einstein's theory of General Relativity provided a more accurate and comprehensive understanding of gravity, describing it not as a force, but as a curvature of spacetime caused by the presence of mass and energy. This theory explains phenomena like gravitational lensing and the existence of black holes.