Sunday, October 11, 2015

Moon: Autolycos

Autolycus (bottom) and Aristillus (top) from Apollo 15 Mapping camera.
James Stuby based on NASA image - Wikimedia

Autolycos Crater
Autolycus is a lunar impact crater that is located in the southeast part of Mare Imbrium. West of the formation is Archimedes, a formation more than double the size of Autolycus. Just to the north is Aristillus, and the outer ramparts of these two craters overlap in the intermediate stretch of the lunar mare.

The rim of Autolycus is somewhat irregular, although generally circular overall. It has a small outer rampart and an irregular interior with no central peak. It possesses a light ray system that extends for a distance of over 400 kilometers. Due to its rays, Autolycus is mapped as part of the Copernican System. Some of the ray material appears to overlay the flooded floor of Archimedes, and thus Autolycus is older than Archimedes. Aristillus (to the north), however, has rays that overlay both Autolycus and Archimedes, and thus it is the youngest of the three craters.

Autolycos of Pitane
Autolycus of Pitane (Greek: Αὐτόλυκος ὁ Πιταναῖος; c. 360 – c. 290 BC) was a Greek astronomer, mathematician, and geographer. Autolycus was born in Pitane, a town of Aeolis within Ionia, Asia Minor. Of his personal life nothing is known, although he was a contemporary of Aristotle and his works seem to have been completed in Athens within the years 335 BC and 300 BC.

On the Moving Sphere is believed to be the oldest mathematical treatise from ancient Greece that is completely preserved. All Greek mathematical works prior to Autolycus' Spheres are taken from later summaries, commentaries, or descriptions of the works. One reason for its survival is that it had originally been a part of a widely used collection called Little Astronomy, which was preserved by translation into Arabic in the 9th century. In Europe, it was lost, but was brought back during the crusades in the 12th century, and translated back into Latin. In his Sphere, Autolycus studied the characteristics and movement of a sphere.

In astronomy, Autolycus studied the relationship between the rising and the setting of the celestial bodies in his treatise in two books entitled On Risings and Settings. The second book is actually an expansion of his first book and of higher quality. He wrote that "any star which rises and sets always rises and sets at the same point in the horizon." Autolycus relied heavily on Eudoxus' astronomy and was a strong supporter of Eudoxus' theory of homocentric spheres.

Excerpts from Wiki texts have been incorporated into the blog as kinds of abstracts for reader's convenience. By clicking the links much more can be learned about these subjects.

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