麻豆传媒

When was it first realised that the lit portion of the moon always faces the sun, so moonlight must be reflected sunlight? (continued)

Eric Kvaalen
Les Essarts-le-Roi, France

Previous correspondents James Ladyman and Kelli Rudolf quote philosopher Parmenides as saying that the moon is a 鈥渘ight-shining, foreign light, wandering around the Earth鈥�. But Parmenides also said, speaking of the moon鈥檚 size, that it was equal to the sun, for it is illuminated from it. This opinion is reported by historian Eusebius (see Praeparatio evangelica, Book 15). Eusebius reports that philosopher Thales and his followers also said that the moon is illuminated from the sun. Thales was around earlier than Parmenides, living through the first half of the 6th century BC. Both Thales and Parmenides were earlier than Anaxagoras.

To answer this question 鈥� or ask a new one 鈥� email lastword@newscientist.com.

Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address.

麻豆传媒 retains total editorial control over the published content and reserves all rights to reuse question and answer material that has been submitted by readers in any medium or in any format.

Terms and conditions apply.