E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Sun and Moon Falling.
By the old heralds the arms of royal houses were not emblazoned by colours, but by sun, moon, and stars. Thus, instead of or (gold), a royal coat has the sun; instead of argent (silver), the moon; instead of the other five heraldic colours, one of the other five ancient planets. In connection with this idea, read Matt. xxiv. 29: Immediately after the tribulation of those days shall the sun be darkened, and the moon shall not give her light, and the stars shall fall from heaven, and the powers of the heavens shall be shaken. (See PLANETS.)