(Last edited: Saturday, 30 September 2023, 10:29 PM)

Image/Video/Audio: Image/Video/Audio Source: Newton, I. (1687, January 1). Isaac Newton's diagram from the 'Principia' of 1687 (Book 3, Proposition 25, at p.434). wikimedia commons. https://commons.wikimedia.org/wiki/File:096-newt1687-figp434.jpg

Short Definition:

Lunar Theory is the
measurement and prediction of the movements of the moon as a method
of a priori deduction with the principles of the laws of gravity. For
the first time in the modern era, Isaac Newton mentioned in his book
Principia in 1687 that the motion of the moon could be calculated
mathematically by the law of gravity.

Detailed Definition:

Lunar theory, the theory
that the movements of the moon can be calculated by gravitational
laws, put forward by Isaac Newton in 1687, is a cumulative result of
moon observations that found their roots in ancient Babylonian, Greek
and Arabian geography. In his book, Newton's Principia, he made the
first inferences about how the gravitational motion of the Earth and
Moon towards the sun could be measured mathematically. With the
development of technology, especially after the 1960s, lunar theory
has been retested with the help of automatic digital computation and
modern observational data-types. With computer-assisted algebra, new
analytical developments have been experienced, and new analytical
theories have been created.

‘’These views, however,
are due to a lack of understanding of the close relation that exists
between the kinematical model of Horrocks, and the dynamical lunar
theory of Newton.’’