Gravity

Gravity

You sometimes speak of gravity as essential and inherent to matter. Pray do not ascribe that notion to me, for the cause of gravity is what I do not pretend to know, and therefore would take more time to consider of it.  — Sir Isaac Newton

Letter to Dr. Bentley (17 Jan 1692). In Four Letters from Sir Isaac Newton to Doctor Bentley (1756), 20. 

Gravity is one the four fundamental forces. Every single interaction that can be observed taking place in the universe can be described by one of four types of interactions; the other three categories being electromagnetism, weak interaction, and strong interaction. These forces, or fundamental interactions, of physics are the ways in which individual particles interact with each other. The chart below shows the relative strength, range, and particle associated with each force: (Angela)

Fundamental Forces |

Name | Relative

Strength | Range

(meters) | Particle |

Strong | 1 | 2x10-15 | Gluon |

Electromagnetic | 10-3 | infinity | Photon |

Weak | 10-16 | 10-18 | Boson |

Gravitational | 10-41 | infinity | Graviton |

The strong interaction is responsible for holding nuclei of atoms together. It is the strongest of the forces, but it has a very short range of order 1013 centimeters. It is basically attractive, but can be effectively repulsive in some circumstances. The next strongest force is the electromagnetic force. This force is responsible for electric and magnetic effects such as the repulsion between like electrical charges or the interaction of bar magnets. It has an infinite range, and acts only between pieces of matter carrying electrical charge. The third strongest forces is the rightly named the weak force. This forces has a very short range ,and is responsible for radioactive decay and neutrino interactions. (The Fundamental forces of Nature) The last and weakest of these forces is gravity.

Gravity is the force responsible for keeping the planets in orbit around the sun...