secular
(occurring slowly over a long period of time)
The term secular, as used in astronomy, indicates changes happening
very slowly, i.e., the change takes a long period of time. It is
used to distinguish such a change from more rapid changes occurring
to the same object/system. Sometimes it is also meant to
imply a (long-term) non-periodic change, to distinguish it from an ongoing
(shorter-term) periodic change. The term is often used in the kinematics
of planets and their orbits: the Earth orbits the Sun
very regularly, but over thousands or millions of years, there
are changes in its orbit, termed secular. Some phrases:
- secular variation or secular motion
- secular evolution (phrase seen regarding slow changes in galaxies).
- "secular phenomena"
- "secular perturbation"
- "secular chaos"
- "secular acceleration"
- "secular drift"
The term is also used in time series analysis, with an analogous meaning.
(astronomy,dynamics,orbits,kinematics)
Further reading:
https://en.wikipedia.org/wiki/Secular_variation#Astronomy
https://www.britannica.com/science/secular-perturbation
https://astronomy.swin.edu.au/cosmos/s/Secular+Evolution
https://www.oxfordreference.com/view/10.1093/oi/authority.20110803100451674
Referenced by pages:
celestial mechanics
gravitational instability (GI)
instability region
Jacobi integral
Kozai mechanism (ZLK)
Laplace-Lagrange secular theory
orbital resonance
parallax
perturbation theory
quenched galaxy
Index