Broca's Brain: Reflections on the Romance of Science by Carl Sagan

Author:Carl Sagan [Sagan, Carl]
Language: eng
Format: azw3, mobi
ISBN: 9780307800992
Publisher: Random House Publishing Group
Published: 2011-07-06T04:00:00+00:00

CHAPTER 11

A PLANET

NAMED GEORGE

And teach me how

To name the bigger light, and how the less,

That burn by day and night …

WILLIAM SHAKESPEARE,

The Tempest, Act I, Scene 2

“Of course they answer to their names?” the Gnat remarked carelessly.

“I never knew them to do it,” [said Alice.]

“What’s the use of their having names,” said the Gnat, “if they won’t answer to them?”

LEWIS CARROLL,

Through the Looking Glass

THERE IS ON the Moon a small impact crater called Galilei. It is about 9 miles across, roughly the size of the Elizabeth, New Jersey, greater metropolitan area, and is so small that a fair-sized telescope is required to see it at all. Near the center of that side of the Moon which is perpetually turned toward the Earth is a splendid ancient battered ruin of a crater, 115 miles across, called Ptolemaeus; it is easily seen with an inexpensive set of field glasses and can even be made out, by persons of keen eyesight, with the naked eye.

Ptolemy (second century A.D.) was the principal advocate of the view that our planet is immovable and at the center of the universe; he imagined that the Sun and the planets circled the Earth once daily, imbedded in swift crystalline spheres. Galileo (1564–1642), on the other hand, was a leading supporter of the Copernican view that it is the Sun which is at the center of the solar system and that the Earth is one of many planets revolving around it. Moreover, it was Galileo who, by observing the crescent phase of Venus, provided the first convincing observational evidence in favor of the Copernican view. It was Galileo who first called attention to the existence of craters on our natural satellite. Why, then, is crater Ptolemaeus so much more prominent on the Moon than crater Galileo?

The convention of naming lunar craters was established by Johannes Höwelcke, known by his Latinized name of Hevelius. A brewer and town politician in Danzig, Hevelius devoted a great deal of time to lunar cartography, publishing a famous book, Selenographia, in 1647. Having hand-etched the copper plates used for printing his maps of the telescopic appearance of the Moon, Hevelius was faced with the question of what to name the features depicted. Some proposed naming them after Biblical personages; others advocated philosophers and scientists. Hevelius felt that there was no logical connection between the features on the Moon and the patriarchs and prophets of thousands of years earlier, and he was also concerned that there might be substantial controversy about which philosophers and scientists—particularly if they were still alive—to honor. Taking a more prudent course, he named the prominent lunar mountains and valleys after comparable terrestrial features: as a result we have lunar Apennines, Pyrenees, Caucasus, Juras and Atlas mountains and even an Alpine valley. These names are still in use.

Galileo’s impression was that the dark, flat areas on the moon were seas, real watery oceans, and that the bright and rougher regions densely studded with craters were continents. These maria (Latin for “seas”)

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