Sunday, October 4, 2015

Moon: Erastothenes

"Eratosthenes crater on the Moon" by Exoexo -
Taken with my telescope and mono web camera.
Previously published:
 Licensed under CC BY-SA 3.0 via Commons

Naming things is human
In the book of Genesis, Adam gives names and thus establishes identities to all things. Nameless thing somehow just does not exist in the same way as the one identified by a name.
Now the LORD God had formed out of the ground all the wild animals and all the birds in the sky. He brought them to the man to see what he would name them; and whatever the man called each living creature, that was its name.
Gen 2:19 NIV

Also the features of Moon visible to the naked eye have been named long ago by humans and are globally known by the rather poetic historical nomenclature given to them by the Europeans. The naming process continues today as experts notice new features by improved observation instruments such as those carried by Lunar probes.

One man has been particularly influential in naming the visible features of the Moon.
Giovanni Battista Riccioli (17 April 1598 – 25 June 1671) was an Italian astronomer and a Catholic priest in the Jesuit order. He is known, among other things, for his experiments with pendulums and with falling bodies, for his discussion of 126 arguments concerning the motion of the Earth, and for introducing the current scheme of lunar nomenclature.

Erastothenes Crater
One of the craters important to the study of the Moon has been named after the Greek genius Erastothenes.
Eratosthenes is a relatively deep lunar impact crater that lies on the boundary between the Mare Imbrium and Sinus Aestuum mare regions. It forms the western terminus of the Montes Apenninus mountain range. The crater has a well-defined circular rim, terracedinner wall, central mountain peaks, an irregular floor, and an outer rampart of ejecta. It lacks a ray system of its own, but is overlain by rays from the prominent crater Copernicus to the south-west.

It is named after Ancient Greek Astronomer, Eratosthenes of Cyrene, who estimated the diameter of the earth, and the distance to the moon and sun.

The Eratosthenian period in the lunar geological timescale is named after this crater, though it does not define the start of this time period. The crater is believed to have been formed about 3.2 billion years ago.

Erastothenes of Cyrene
Eratosthenes of Cyrene (Greek: Ἐρατοσθένης, c. 276 BC – c. 195/194 BC) was a Greek mathematician, geographer, poet,astronomer, and music theorist. He was a man of learning, becoming the chief librarian at the Library of Alexandria. He invented the discipline of geography, including the terminology used today.

He is best known for being the first person to calculate the circumference of the Earth, which he did by applying a measuring system using stadia, a standard unit of measure during that time period. His calculation was remarkably accurate. He was also the first to calculate the tilt of the Earth's axis (again with remarkable accuracy). Additionally, he may have accurately calculated the distance from the Earth to the Sun and invented the leap day. He created the first map of the world incorporating parallels and meridians, based on the available geographical knowledge of the era.

Eratosthenes was the founder of scientific chronology; he endeavored to revise the dates of the chief literary and political events from the conquest of Troy. In number theory, he introduced the sieve of Eratosthenes, an efficient method of identifying prime numbers.

Erastothenes was a friend of Archimedes, whose name was given to the largest crater on Mare Imbrium.

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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