One of the forces of nature. It is an attractive force exerted between two or more particles all of which have mass.
- Discovered by Isaac Newton around 1690, who stated the law of gravity:
- "Every mass in the Universe attracts every other with a force proportional to the product of their masses and inversely proportional to their distance of separation squared".
Despite being the weakest force of nature, gravity shapes the universe on the largest of scales. It is long range, i.e. it extends from a mass to infinity. It is an unsaturated force, that is, the more masses that aggregate together the greater the force (unlike the short range forces in a drop of liquid that remain unchanged no matter how large the drop). Unlike electromagnetism, gravity only attracts: it does not repel. General relativity is the best theory to explain the effects of gravity.
- Further reading:
- Advanced Physics for You, , Nelson Thornes