Quote(NOTE: No mention of "planet" other than the one on which the beings - human beings in this case - stand)
The planets are stars in this analysis--they are the "wandering stars" spoken of in the Letter to Pythocles;
QuoteThat some of the stars should wander in their course, if indeed it is the case that their movements are such, while others do not move in this manner, may be due to the reason that from the first as they moved in their circles they were so constrained by necessity that some of them move along the same regular orbit, and others along one which is associated with certain irregularities: or it may be that among the regions to which they are carried in some places there are regular tracts of air which urge them on successively in the same direction and provide flame for them regularly, while in other places the tracts are irregular, so that the aberrations which we observe result.
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τινὰ τῶν ἄστρων πλανᾶσθαι, εἰ οὕτω ταῖς κινήσεσι χρώμενα συμβαίνει, τινὰ δὲ ὁμαλῶς κινεῖσθαι, 177 [113] ἐνδέχεται μὲν καὶ παρὰ τὸ κύκλῳ κινούμενα ἐξ ἀρχῆς οὕτω κατηναγκάσθαι, ὥστε τὰ μὲν κατὰ τὴν αὐτὴν δίνην φέρεσθαι ὁμαλῆ οὖσαν, τὰ δὲ κατά τιν᾽ ἄλλην τισὶν ἀνωμαλίαις χρωμένην.
ἄστρων πλανᾶσθαι, astron planasthai, wandering stars. Planet means 'wanderer'.