Secularity
Article
In astronomy, secular phenomena are changes that develop gradually over very long timescales rather than repeating as short, obvious periodic cycles. The word secular is used in the sense of age-long or long-term.
Examples include slow changes in planetary orbital elements, the gradual acceleration or deceleration of rotations, tidal evolution, stellar evolution, and long-period perturbations in celestial systems.
A secular variation may appear approximately linear over a limited interval, even though the complete system is governed by more complex dynamics. Some secular effects are accompanied by smaller periodic oscillations.
Studying secular changes requires long observational records, precise historical data, and dynamical modelling. These effects are important when predicting planetary positions, eclipse timing, satellite motion, and the long-term stability of the Solar System.
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- Source / publisher: Wikipedia
- URL type: WWW
- Credits: Wikipedia
- URL: https://en.wikipedia.org/wiki/Secular_phenomena