the word circada appears in two very distinct locations.

Aurora (mythology)
https://en.m.wikipedia.org/wiki/Aurora_mythology

Frankish (mythology)
https://en.m.wikipedia.org/wiki/Frankish_mythology

something to do with..

Rta
https://en.m.wikipedia.org/wiki/Ṛta

Aurora & Tetahertz Gap =RED
..

Local Interstellar Cloud
https://en.m.wikipedia.org/wiki/Local_Interstellar_Cloud

Secular Variation
https://en.m.wikipedia.org/wiki/Secular_variation

Jumping-Jupiter Scenario
https://en.m.wikipedia.org/wiki/Jumping-Jupiter_scenario

In the solar system secular phenomena create variations in the orbits of the Moon and the planets. The solar emission spectrum and the solar wind are undergoing secular trends due to migration through the galactic plane, leading to effects that may impact on climate and cause extinction events.