The ancient Greeks observed that the positions of ascending and descending nodes at which the Moon passes through the fixed plane of the Earth's orbit around the Sun, the ecliptic, decrease, i.e. orbit the Earth in the opposite direction to the Moon, in such a rate that the cycle of that regression amounts almost exactly 18.6 Earth's years. In other words, if the Moon, during the spring or autumn equinox, when viewed from stationary point on Earth, ascends at a certain position on the east horizon, describes the curve of his path and descends at another particular point on the west horizon, it would take 18.6 years for this trajectory to be repeated. In past centuries, developing lunar theory, many famous mathematicians and astronomers have dealt with described problem (Newton, Clairaut, D'Alembert, Euler, Laplace, Damoiseau, Plana, Poisson, Hansen, De Pontécoulant, J. Herschel, Airy, Delaunay, G.W. Hill, E.W. Brown) indicating its inherent difficulty and the theoretical and practical importance.
The background sound is Simphonies of planets recorded by NASA Voyager.
Loading more stuff…
Hmm…it looks like things are taking a while to load. Try again?