They are just conglomerations of ordinary atoms of air or fire--it does not matter which. They are not even very large--only about as large as they look, or perhaps smaller, since most fires tend to look bigger at a distance. They are not at all certainly everlasting. It is quite likely that the sun comes to an end every day, and a new one rises in the morning. All kinds of explanations are possible, and none certain. Μόνον ὁ μῦθος ἀπέστω. In any case, as you value your life and your reason, do not begin making myths about them! On other lines came what might have been the effective protest of real Science, when Aristarchus of Samos (250 B. C.) argued that the earth was not really the centre of the universe, but revolved round the Sun. But his hypothesis did not account for the phenomena as completely as the current theory with its 'Epicycles'; his fellow astronomers were against him; Cleanthes the Stoic denounced him for 'disturbing the Hearth of the Universe', and his heresy made little headway.[141:1] The planets in their seven spheres surrounding the earth continued to be objects of adoration. They had their special gods or guiding spirits assigned them. Their ordered movements through space, it was held, produce a vast and eternal harmony. It is beautiful beyond all earthly music, this Music of the Spheres, beyond all human dreams of what music might be. The only pity is that--except for a few individuals in trances--nobody has ever heard it. Circumstances seem always to be unfavourable. It may be that we are too far off, though, considering the vastness of the orchestra, this seems improbable. More likely we are merely deaf to it because it never stops and we have been in the middle of it since we first drew breath.[142:1] The planets also become Elements in the Kosmos, _Stoicheia_. It is significant that in Hellenistic theology the word Stoicheion, Element, gets to mean a Daemon--as Megathos, Greatness, means an Angel.[142:2] But behold a mystery! The word _Stoicheia_, 'elementa', had long been used for the Greek A B C, and in particular for the seven vowels α ε η ι ο υ ω. That is no chance, no mere coincidence. The vowels are the mystic signs of the Planets; they have control over the planets. Hence strange prayers and magic formulae innumerable. Even the way of reckoning time changed under the influence of the Planets. Instead of the old division of the month into three periods of nine days, we find gradually establishing itself the week of seven days with each day named after its planet, Sun, Moon, Ares, Hermes, Zeus, Aphrodite, Kronos. The history of the Planet week is given by Dio Cassius, xxxvii. 18, in his account of the Jewish campaign of Pompeius. But it was not the Jewish week. The Jews scorned such idolatrous and polytheistic proceedings. It was the old week of Babylon, the original home of astronomy and planet-worship.[143:1]