The Eternity of the Universe in tōtō [in total] as a boundless plane; periodically “the playground of numberless Universes incessantly manifesting and disappearing,” called “the manifesting stars,” and the “sparks of Eternity.” “The Eternity of the Pilgrim” is like a wink of the Eye of Self-Existence . “The appearance and disappearance of Worlds is like a regular tidal ebb of flux and reflux.” This second assertion of the Secret Doctrine is the absolute universality of that law of periodicity, of flux and reflux, ebb and flow, which physical science has observed and recorded in all departments of nature. An alternation such as that of Day and Night, Life and Death, Sleeping and Waking, is a fact so common, so perfectly universal and without exception, that it is easy to comprehend that in it we see one of the absolutely fundamental laws of the universe.
The Secret Doctrine Book i page 17 H.P. Blavatsky