Τῶν μὲν οὖν καλουμένων Πυθαγορείων φασί 15τινες ὁδὸν εἶναι ταύτην οἱ μὲν τῶν ἐκπεσόντων τινὸς ἀστέρων, κατὰ τὴν λεγομένην ἐπὶ Φαέθοντος φθοράν, οἱ δὲ τὸν ἥλιον τοῦτον τὸν κύκλον φέρεσθαί ποτέ φασιν· οἷον οὖν διακεκαῦσθαι τὸν τόπον τοῦτον ἤ τι τοιοῦτον ἄλλο πεπονθέναι πάθος ὑπὸ τῆς φορᾶς αὐτῶν.
Ἄτοπον δὲ τὸ μὴ συννοεῖν ὅτι εἴπερ τοῦτ᾿ ἦν 20τὸ αἴτιον, ἔδει καὶ τὸν τῶν ζῳδίων κύκλον οὕτως ἔχειν, καὶ μᾶλλον ἢ τὸν τοῦ γάλακτος· ἅπαντα γὰρ ἐν αὐτῷ φέρεται τὰ πλανώμενα καὶ οὐχ ὁ ἥλιος μόνος. δῆλος δ᾿ ἡμῖν ἅπας ὁ κύκλος· αἰεὶ γὰρ αὐτοῦ φανερὸν ἡμικύκλιον τῆς νυκτός. ἀλλὰ πεπονθὼς οὐδὲν φαίνεται τοιοῦτον, πλὴν εἴ τι 25συνάπτει μόριον αὐτοῦ πρὸς τὸν τοῦ γάλακτος κύκλον.
Οἱ δὲ περὶ Ἀναξαγόραν καὶ Δημόκριτον φῶς εἶναι τὸ γάλα λέγουσιν ἄστρων τινῶν· τὸν γὰρ ἥλιον ὑπὸ τὴν γῆν φερόμενον οὐχ ὁρᾶν ἔνια τῶν ἄστρων. ὅσα μὲν οὖν περιορᾶται ὑπ᾿ αὐτοῦ, τούτων μὲν οὐ φαίνεσθαι τὸ φῶς (κωλύεσθαι γὰρ ὑπὸ 30τῶν τοῦ ἡλίου ἀκτίνων)· ὅσοις δ᾿ ἀντιφράττει ἡ γῆ ὥστε μὴ ὁρᾶσθαι ὑπὸ τοῦ ἡλίου, τὸ τούτων οἰκεῖον φῶς εἶναί φασι τὸ γάλα. φανερὸν δ᾿ ὅτι
The so-called Pythagoreans give two explanations. A. Previous views: (1) the Pythagoreans; Some say that the Milky Way is the path taken by one of the stars at the time of the legendary fall of Phaethon: others say that it is the circle in which the sun once moved.a And the region is supposed to have been scorched or affected in some other such way as a result of the passage of these bodies. But it is absurd not to see that if this is the cause, the circle of the zodiac should also be so affected, indeed more so than the Milky Way: for all the planets, as well as the sun, move in it. But though the whole zodiac circle is visible to us (for we can see half of it at any time during the night) it shows no sign of being so affected, except when a part of it overlaps the Milky Way.
The schools of Anaxagorasb and Democritusc (2) Anaxagoras and Democritus; maintain that the Milky Way is the light of certain stars. The sun, they say, in its course beneath the earth, does not shine upon some of the stars; the light of those upon which the sun does shine is not visible to us, being obscured by its rays, while the Milky Way is the light peculiar to those stars which are screened from the sun’s light by the earth.d This
- aDiels 58 B 37 c. The second view is attributed also to Oenopides; Diels 41. 10 (Heath, Aristarchus, p. 133).
- bDiels 59 A 1 (ii. 6. 2); 42 (ii. 6. 31); 80.
- cIbid. 68 A 91.
- d“As we have seen, he (Anaxagoras) thought the sun to be smaller than the earth. Consequently, when the sun in its revolution passes below the earth, the shadow cast by the earth extends without limit. The trace of this shadow on the heavens is the Milky Way. The stars within this shadow are not interfered with by the light of the sun, and we therefore see them shining; those stars, on the other hand, which are outside the shadow are overpowered by the light of the sun, which shines on them even during the night, so that we cannot see them.” So Heath (Aristarchus, p. 83) summarizes this passage. What is not easy to understand is why, on Anaxagoras’ theory, we see any stars outside the Milky Way, if the light of stars outside it is “overpowered by the light of the sun.” Alex. 37. 24–27 implies that such stars owe their light to reflection from the sun. Anaxagoras was the first to discover that the moon owes its light to the sun (Heath, op. cit. p. 78); he may have held that the stars outside the Milky Way did too.