*World of Earth Science*. ©2005-2006 Thomson Gale, a part of the Thomson Corporation. All rights reserved.

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## Gravity and the Gravitational Field

Geophysicists utilize slight variations in gravitational force to characterize the mass of subsurface features. Particularly useful in **petroleum** exploration, subtle gravitational field differences can help identify solid subsurface plutonic bodies or fluid filled reservoirs.

1n 1687, English physicist **Sir Isaac Newton** (1642–1727) published a law of universal gravitation in his important and influential work *Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy)*. In its simplest form, Newton's law of universal gravitation states that bodies with mass attract each other with a force that varies directly as the product of their masses and inversely as the square of the distance between them. This mathematically elegant law, however, offered a remarkably reasoned and profound insight into the mechanics of the natural world because it revealed a cosmos bound together by the mutual gravitational attraction of its constituent particles. Moreover, along with Newton's...

This section contains 1,137 words(approx. 4 pages at 300 words per page) |