Pythagoras added that at death the ethereal part of man freed from the chains of matter is conducted by Hermes Psychopompos, the Guide of Souls, into the region of the dead, where it remains in a state according to its merit until it is sent back to earth to inhabit another body. The object of rebirth is gradually to purify the soul by successive probations, until finally it shall be fitted to return to the immortal source whence it emanated. (5) The Earth and the Universe It is well-known that the ideas expressed by Plato in his _Timaeus_, the dialog which he named after his Pythagorean teacher, are derived almost entirely from Pythagorean sources. Therefore it is probable that Pythagoras taught about the earlier continents, which were destroyed alternately by fire and water, and in particular about the legends of Atlantis, including the account of an Atlantean invasion of Greece about 10,000 years B. C. before the Greeks lived in the Greek lands--an invasion which was repelled by the inhabitants of prehistoric Athens, who were akin to the ancient Egyptians. In regard to our solar system, Pythagoras knew not only that the earth is spherical, but also taught that the sun, likewise spherical, not the earth, is the center--a theory rediscovered more than 2000 years later by Copernicus and Galileo. Pythagoras also explained the obliquity of the ecliptic, the causes of eclipses, that the morning and evening star are the same, that the moon shines by light reflected from the sun, and that the Milky Way is composed of stars. He held that "the Universe has neither height nor depth but is infinite in extent," that there is a void outside the Universe into which the Universe breathes forth and from which it breathes in, and that the Universe is brought into being by the Deity and is perishable so far as its shape is concerned, for it is perceived by sense, is therefore material, but that (its Essence) will not be destroyed. Pythagoras declared that all nature is animate, for Soul is extended through the nature of all things and is mingled with them and he believed in one Deity, ruling and upholding all things. There is One Universal Soul diffused through all things--eternal, invisible, unchangeable; in essence like Truth, in substance resembling Light; not to be represented by any image; to be comprehended only by the _Nous_; not, as some conjecture, exterior to the Universe, but in itself entire, pervading the sphere which is the Universe.