The Purse of Eratosthenes

For about 10 years in the 1990s, I worked on assembling a collection of ancient coins worth about a day's wages from the towns and times of Greek philosophers. I was inspired by an episode of Carl Sagan's Cosmos, "Backbone of the Night." Although I discovered that I lack the passions of a true collector for rarity, condition, and completeness, I was rewarded with explorations in ancient history and the opportunity to learn enough classical Greek to do my own translations.

Drachmon from Kyrene c. 550 BCE Zeus Ammon and Silphium
(About the size of US 5-cent nickel)

I discovered the town of Cyrene (Kyrene), near what is today Benghazi. Eratosthenes of Cyrene was the third Librarian of Alexandria (from 245 BCE) after Zenodochus and Callimachus. Circumference by Nicholas Nicastro (St. Martins 2008) reviewed on this blog (here) is a modern biography of Eratosthenes and his works. He was also a grammarian and historian. His other mathematical work includes a "sieve" to find prime numbers.  His biography is on Wikipedia, of course: https://en.wikipedia.org/wiki/Eratosthenes  It is also repeated more succinctly here: 
http://www.math.wichita.edu/history/men/eratosthenes.html  
and more fully here:
http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Eratosthenes.html

The Hellenistic world was very much like our own time: held in tension by science and superstition, commerce and war, ecumenism and parochialism.

Kyrene was founded by Dorians from the island of Thera in 631 BCE. Its primary claim to fame was the presence of silphium. Silphium was discovered to prevent pregnancy. It was highly valued and eventually harvested to extinction, despite valiant attempts to cultivate it there and elsewhere. Not surprisingly, the history of Kyrene reflected many of the cultural trends of the times. Twice, it suffered from constitutional crises as factions in the assembly became gangs in the streets. Both times, the solution was to send to Athens for philosophers skilled at politics who created compromises. 

Obol or hemi-drachm. Demeter with Eagle killing snake.
(About half the size of a US dime.)

The town also was home to two women who married a Ptolemy: Berenike I and Berenike II. The constellation Coma Berenices was supposedly the hair  of Berenike II, offered to the gods for the safe return of Ptolemy III Euergetes from a war in Syria. "Veronica" is the latinized form of Berenike. 

Among the ancient philosophers, the Cyrenaics followed the teachings of Aristippos. The school was maintained and extended by his daughter, Arete, and her son, Aristippos. Though originally a student of Socrates, Aristippos asserted his own line of thought. He advocated seeking pleasure by adapting to circumstances. He gave up the safety of a city and traveled widely. To understand the consequences of that, remember that Diogenes the Cynic was captured by pirates and sold as a slave. It was not unusual for the times. There was no safety outside the city walls. Yet, the Alexandrians coined the word "cosmopolitan" for the universal citizen or citizen of the world, not tied to any one city, but comfortable anywhere.

Ptolemy II and Berenike I. Alexandria Mint.
(Bronze coin about the size of a US quarter)

Eratosthenes, the town of Kyrene, and the Library at Alexandria became a focus for my interests and one of the first articles I wrote about the numsimatics of the ancient world was “The Purse of Eratosthenes: the Coinage and Commerce of Cyrene,” The Celator, Vol. 8, no 1, (January 1994).  (Founded by Wayne G. Sayles, The Celator passed to a couple of other editors and publishers and then closed just a few years ago.)  

We quip and quote about the long run of history, which may or may not repeat itself to our doom. The fact is that the Library of Alexandria attracted savants from all across the Greek koinon ("union").  They developed their own distinct and universal dialect, in which, ultimately, the New Testament was written. When the house of Ptolemy fell on hard times, the library released many of its scholars to find their own ways. Rather than marking a nadir, it caused a secondary flourishing in the Hellenistic world as accumulated learning was cast to the winds to flourish wherever open minds were found.

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Anthropocene: bad name for a good thing

The Age of Man: humanity as a global culture; our cities a new environment, a new ecology, an invented eco-system.  It is inspiring.  But it is wrongly named. 

Recent articles from popular scientific literature delineate the problem.  “Is Civilization Natural?” by Adam Frank aired on NPR, September 26, 2014.  That is how I first learned the word in my car the following day.   

Reading the blog transcript, I followed the links and searched on my own.  I found a National Geographic story from 2011, “Enter the Anthropocene-Age of Man” by Elizabeth Kolbert.  In its January 2013 issue, Smithsonian Magazine asked rhetorically, “What is the Anthropocene; and are we in it?” by Joseph Stromberg. 

First, is the presence of human civilization remarkable in geologic time?  Second, if so, what is the proper name?  The second problem is only hinted at.  No one seems to have offered a better label.  As for the first, it depends on whom you ask. 

 

Earth from Space. Apollo 8.
No indication that it is inhabited.

According to National Geographic, the word “anthropocene” was invented spontaneously by Paul Crutzen, a Nobel laureate chemist. 

“The conference chairman kept referring to the Holocene, the epoch that began at the end of the last ice age, 11,500 years ago, and that—officially, at least—continues to this day. "'Let's stop it,'" Crutzen recalls blurting out. "'We are no longer in the Holocene. We are in the Anthropocene.' Well, it was quiet in the room for a while." When the group took a coffee break, the Anthropocene was the main topic of conversation.”

 In truth, Crutzen has been thinking about this for about 40 years.  His first listing in JSTOR is “SST’s – A Threat to the Earth’s Ozone Shield” in Ambio, vol. 1 no. 2, April 1972.  SST refers to the Concorde supersonic transport, a commercial experiment that ran for 27 years, from 1976 until 2003.  Only 100 were ordered, 20 built, and seven put into service.  When Crutzen wrote in 1972, they were four years in the future.

Crutzen continued to research atmospheric chemistry, and was honored with a Nobel prize, in 1995, along with Mario Molina, and F. Sherwood Rowland, for his work on ozone depletion.  But he is not a geologist.

The –cene words all mean “recent.”  From the Tertiary Period through the Quaternary Period, the Epochs are called (oldest first):  Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, and Holocene.  They mean: oldest recent, dawn of the recent, slightly recent, more recent, most recent, and wholly recent.  (Idaho Museum of Natural History here.)

 

Earth at Night
Evidence is where you find it.

Stratigraphers define geologic layers by the rocks, of course, but also, more accurately, and precisely by the fossils.  (See The Map that Changed the World reviewed here on NecessaryFacts.) Some stratigraphers were not happy with the neologism “anthropocene” that popped up in the scientific literature.  Others may have settled themselves to it. It depends on whom you ask.  

“Many stratigraphers (scientists who study rock layers) criticize the idea, saying clear-cut evidence for a new epoch simply isn’t there. “When you start naming geologic-time terms, you need to define what exactly the boundary is, where it appears in the rock strata,” says Whitney Autin, a stratigrapher at the SUNY College of Brockport, who suggests Anthropocene is more about pop culture than hard science. The crucial question, he says, is specifying exactly when human beings began to leave their mark on the planet: The atomic era, for instance, has left traces of radiation in soils around the globe, while deeper down in the rock strata, agriculture’s signature in Europe can be detected as far back as A.D. 900. The Anthopocene, Autin says, “provides eye-catching jargon, but from the geologic side, I need the bare bones facts that fit the code.”  (Smithsonian Magazine.)

“At first most of the scientists using the new geologic term were not geologists. [Dr. Jan] Zalasiewicz, [University of Leicester] who is one, found the discussions intriguing. "I noticed that Crutzen's term was appearing in the serious literature, without quotation marks and without a sense of irony," he says. In 2007 Zalasiewicz was serving as chairman of the Geological Society of London's Stratigraphy Commission. At a meeting he decided to ask his fellow stratigraphers what they thought of the Anthropocene. Twenty-one of 22 thought the concept had merit.” (National Geographic)

(See, also, “The Anthropocene: a new epoch of geological time?” by Jan Zalasiewicz, Mark Williams, Alan Haywood, and Michael Ellis. Philosophical Transactions: Mathematical, Physical and Engineering Sciences, Vol. 369, No. 1938, (13 March 2011), pp. 1056-1084, by The Royal Society.)

Geologic stages are shorter than epochs and they tend to be named after the places where the layers were first explored, even if similar layers are found elsewhere: Piacenzian, Gelasian, Calabrian …  But the margins of error are still given as ± 0.005 million years, which means ± 5000 years, the time span of the so-called Anthropocene. 

Geologic time is not the only long wave.  The 1954 reference Earth as a Planet, edited by Gerard P. Kuiper, has no index entries for humans, animals, or plants.  About halfway through the 744-page work, in a chapter by G. E. Hutchinson of Yale, "The Biochemistry of the Terrestrial Atmosphere", is this passage:  “The carbon cycle, as it is commonly understood in biology, consists of the photosynthetic reduction of CO2 by green plants and a certain number of purple and green bacteria and the subsequent respiratory release by plants, bacteria, and a to a less extent of animals, of Co2 to the atmosphere.” (p. 379).

Man is the measure of all things.  But measurements must be appropriate.  The Moon is 384,403 km away, center to center, even though we do not travel from the center to the center.  Knowing that in millimeters does not give you much more information. 

 

Stars that have been touched by our
television signals
http://zebu.uoregon.edu/1996/ph123/l16c.html

Anthropocene means “Man recent”.  It violates the rules of nomenclature and is gendered.  Why not call this the Gynocene?  The word “people” ultimately comes from a doubling for intensity of the first syllable of “poloi” which means “many.”  (Pepper is another example: achoo!)   Linguists who theorize a common source for all Afro-Asiatic languages use the word “Nostratic” ultimately from the Latin nos for “we” and, so, “nostras” for we-folks, countrymen, natives, etc.  Homo-words carry too many other meanings. We have enough problems with homo erectus.  Civilization may be sine qua non of who we are.  It is not clear when, measured by paleontology, we became rational and self-aware, versus just being smarter apes.  And those may be two different events.  The recent discovery of cave paintings  in Indonesia that are 40,000 years old and similar to equally old works in Europe suggests much, but answers little. 

We have been radiating electromagnetic signals into space since 1840.  Voyager 2 has been on an “interstellar mission” since 1990.  Even though the sun will expand and burn the planet, some of our descendants may witness that.  And, just as we know Paleozoic millimeter-sized plants from their fossils, they too, may have evidence of our having been here now.  

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Megacities

“Today there are more than 20 cities with over 10 million inhabitants. Some are sleek, modern, and hightech; others are filled with slums. BBC journalist Andrew Marr visits five megacities: one of the oldest (London), the fastest-growing (Dhaka, Bangladesh), the largest (Tokyo), one of the most dangerous (Mexico City), and one that considers itself the new world capital (Shanghai).” From Athena Learning and Acorn Online  I believe that these three one-hour episodes can open a door, if not to the right answers, then perhaps to the right questions.  Though I disagreed some of narrator Andrew Marr's opinions, the presentation was important and timely.  

Episode 1: Living in the City

The need to strike a balance between community and efficiency is nowhere more apparent than in megacities. Marr examines Shanghai’s bursting-at-the-seams growth and the isolation of Tokyo. He also spends the night in a Dhaka slum—and despite its crime, pollution, and congestion, finds Mexico City an overwhelmingly friendly and livable place.

Episode 2: Cities on the Edge

How do you protect a city of 20 million people? Some of the dangers of the megacities are natural—earthquakes, floods, typhoons—while others are manmade. Marr takes an evasive driving course in the kidnap capital of the world and volunteers for the London police’s riot unit. In Tokyo, situated on three of the world’s most unstable geological fault lines, he learns how locals have planned for disaster.

Episode 3: Sustaining the City

Highways, roads, rail lines, and subway systems are the arteries of the megacity—and just like human arteries, they can become dangerously clogged. Marr pedals a rickshaw taxi in Dhaka, flies with Mexico City’s airborne traffic cops, and rides a high-speed magnetic railroad in Shanghai. He also finds out what London’s fast-food obsession is doing to its Victorian-era sewers.

I do note that "mega" is relative.  Today over 300 cities have over one million inhabitants. We live on an urban planet. On May 23, 2007, the population of Earth crossed to 50% urban (ScienceDaily). Most of us live in cities.  Are megacities just very large towns or really huge villages; or do they have social structures with special functions different from their predecessors—if indeed, the village is the ancestor of the city.  It may not be.

Historically, cities seem to have blossomed all at once, even as other places have remained villages for 8,000 years.  Sumer and Babylon are gone, but Athens, Rome, London, Shanghai, Tokyo, and even New York, have long continuous histories of almost-uninterrupted growth. 

But even they are not unrelieved deserts of concrete and steel. For a graduate class in Remote Sensing (2010), I wrote a paper on agriculture within megacities.  Moreover, about half of us urbanites are in small cities of fewer than half a million inhabitants. Only about 12% of us live in one of the 28 megacities.  (Christian Science Monitor here and National Geographic here.)

“Ugne Saltenyte, an analyst at the market research firm Euromonitor, recently calculated that 24 percent of the world's population over 15 years of age and with the equivalent of a two-year degree or more is concentrated in the world's 100 largest cities (report here). These same 100 cities — Saltenyte is counting full metropolitan areas here — are home to just 11 percent of the world's total population.” Washington Post here.

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CIRCUMFERENCE

Democritus of Abdera posited the existence of atoms. Aristotle accurately described the embryology of the chick.  Aristarchus put the sun at the center of the planetary system.  Yet nothing like “science” existed before the Renaissance. When Eratosthenes measured the circumference of the Earth by comparing shadows at noon on the summer solstice, remarkable as it was, and enduring as it would prove to be, his work was singular: neither a test, nor a disproof; neither a challenge, nor an argument.  It simply was.  But what was it?

St. Martin's Press, 2008.

 Nicholas Nicastro wrote five historical novels (three of them set in ancient times) before taking on this thin biography.  The life and works of Eratosthenes are mostly lost to us, destroyed when the Great Library of Alexandria and smaller collections across the world were looted and their  books burned as Hellenistic civilization collapsed. What we know about him is second-hand from Strabo, Polybius, the 10^th century Suda, and similar sources.  Nicastro reconstructs as much as seemed relevant to the story here: how and why the librarian of Alexandria computed the size of the Earth as one element in his general geography.  In fact, Eratosthenes invented the word geography.

The Hellenistic world was very much like our own time: held in tension by science and superstition, commerce and war, ecumenism and parochialism.  Nicastro spans all of that because the known facts of the life and works of Eratosthenes are so few.  Much of the book is given over to calculations in various ancient stade measures (whence the modern "stadium").  Like many other technical reads for large audiences, the end notes are not keyed within the text.  Keep a bookmark there so that you can flip back and forth. 

Coin from Cyrene c. 480-435.
3.34 gr.  1.5 cm.
Zeus Ammon / Silphium.

Eratosthenes came from Cyrene, a city in what is today Libya near what is today Benghazi.  He studied philosophy in Athens before being appointed to the Great Library by Ptolemy III Euergetes.  Nicastro underscores the fact that contrary to our common opinions today, Athens was not a home to learning and philosophy until after its Golden Age and eventual downfall in the Peloponnesian Wars. Anaxagoras, Protagoras, and Socrates all had been tried for impiety.  Nicastro also argues that Eratosthenes probably did not travel to Siwa (Aswan) to see the sun overhead.  He might have sent an underling from the Museum to do that.  A single fragment letter from Archimedes to Eratosthenes suggests a long correspondence between the two.  

But Eratosthenes was more than a geometer.  Just as most of Newton’s writings were not about physics, so, too, did Eratosthenes mostly write on grammar, poetry, and history.  That was apparently the attraction for Nicastro. “[He] received a BA in English from Cornell University (1985), an MFA in filmmaking from New York University (1991), an M.A. in archaeology and a Ph.D. in psychology from Cornell (1996 and 2003).” (Wikipedia).  It takes one to know one.

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Ground Truth

Geographers who work with remote sensing data call "ground truth" the final empircal test.  You never know for sure what the instruments are telling you until and unless you go there with your own natural-born senses. 

Over lunch, a couple of months ago, one of my former geography professors told me that despite two years on this field project, one of the graduate assistants became lost when faced with a detour.  Always focused on the vehicle's GPS, the driver had no sense of geographic context.  This is not unsual.

Last month, my wife had a similar experience.  Returning to her apartment from the airport, she told the taxicab driver which turn to make.  Focused on the GPS, the driver insisted on the direct route. Faced with orange barrels, they had to go four blocks around and the difference was the driver's lost tip.  The tip was included; the driver just burned it up. 

This happened to me twice when I first came to Austin.  Eyes nailed on the GPS, drivers from two different companies drove in circles looking for addresses that I could see from the back seat.  They ignored my help - eventually, my pleas.  In the first case, after my meeting, I walked back to the motel, a direct backstreet distance of a quarter-mile that cost me $10 in a taxicab via the freeways, offramps, and access roads.  After the second incident, I decided that I will never take a taxicab in Austin again.  I would rather spend the time waiting for buses, reading a book, than to spend the money on drivers who do not know their city.

I drove a cab three times in the 70s and 80s.  The first time, I was new in town. I depended on the map, of course, but as Alfred Korzybski told us, the map is not the territory.  I made notes.  My third time, though I knew the town much better, I still started out with a fresh map in booklet form, which I annotated, drawing in new subdivisions as I discovered them.  I do not blame a driver for not knowing every street, but I do hold any person morally responsible to use their own senses.

In remote sensing, we learn six ways to create "yellow." 

• A direct radiation of 5600 angstroms.
• Reflection: all other wavelengths absorbed; yellow reflected.
• Full Red and Full Blue with No Green in an RGB display
• Full Yellow and No Cyan and No Magenta in a CMYK display
• Passing White light through a Yellow filter
• Refraction of White light at an appropriate angle

It is a prinicple of objectivism (and empiricism) that the senses cannot be fooled.  When you see an "optical illusion" the trick is in the mind, not the eye.  When you see yellow, yellow is what you see.  However, as the rationalists warn us, we do not necessarily know how the yellow was created.  For that, you need "ground truth."

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