Black Death Predated 'Small World' Effect, Say Network Theorists 168
KentuckyFC writes "Epidemiologists know that modern diseases can spread almost simultaneously in different parts of the planet because an individual who becomes infected in Hong Kong, for example, can infect friends in New York the following day. This is known as the small world effect. It is the same property that allows any individual to link to another individual anywhere in the world in just a few steps. But in the 14th century, the Black Death spread in a very different way, moving slowly across Europe at a rate of about 2 kilometers a day. Now network theorists have simulated this spread and say it is only possible if the number of long distances travelers in those days was vanishingly small. In other words, people in medieval society were linked almost exclusively to others nearby and so did not form a small world network. That raises an interesting question. If society in 14th century Europe was not a small world but today's society is, when did the change occur? The researchers say the finger of blame points to the invention of railways and steamships which allowed large numbers of people, and the diseases they carried, to travel long distances for the first time."
Re:interesting question (Score:5, Interesting)
The "Arab" traders were really a remarkable multi-ethnic amalgamation of Levantine and peninsular Arabs, Africans from the horn, Persians from the gulf, and Indians from the Arabian sea - Malabar Coast and Gujurat. There were also Genoans, Turks and Georgians from the Caucasus - with plenty of overlap by Chinese through the time of Kublai, under the Mongols.
This was the world of Sinbad, and the true inheritor of the great maritime civilizations in the Mediterranean - Tyre, Mycenae and Athens.
Worse Yet (Score:4, Interesting)
Passenger airline traffic has the potential to disperse a world wide plague more deadly than all past wars combined. It is another issue which is shrouded by deliberate blindness as the cure would be very disruptive.
Re:interesting question (Score:5, Interesting)
I think what we tend to forget is how much of a chore that travel was to people that were walking or traveling by wagon. My paternal grandmother grew up in a what was one of the last frontier areas in the central part of the United States, in the late 1890's the 50 mile wide strip of land in western Louisiana that was disputed territory with Spain prior to the Texas Independence in the 1830's , and remained virtually uninhabited until timber rush of the 1880's. The nearest city of any size was the river / ocean port city of Lake Charles 50 miles away by road or 75 miles indirectly by rail 10 miles away (post 1905). During this time the town she lived in was a booming timber mill town with a couple of thousand people, her father owned one of the two general stores in the town, and would travel to Lake Charles once every 4-6 weeks for supplies., this was usually done by wagon, taking 2 or 3 wagons which his children would help drive. This was a 2 day trip, the first day was spent traveling with the empty wagons to a point where there was a ferry that crossed into Lake Charles on the west bank of the Calcasieu river near the present day town of Moss Bluff, where they would camp out over night in the wagons. Early the following morning her father would take the wagons into to Lake Charles (which had a population of 7,000- 12,000 people at this time) to buy goods, leaving the kids at camp to fix food for the day's travel, and prepare the wagons., they would then set off traveling home with their loaded wagons by mid morning, arriving back home late in the evening. Needless to say such long distance travels were not common for many of the children of the community, and likely few of the adults as well, and this was around the turn of the 20's century, well into the age of steam engines, and around the birth of the automobile..
Re:Long distance travel (Score:5, Interesting)
Horses are expensive to maintain, and have a rough daily limit of about 30 miles. In comparison, a human walking at 3 mph can go the same distance in only 10 hours.
That's not comparable. The horse could do that forever (for example, see this US cavalry manual [ibiblio.org] which stipulates cavalry can go 35 miles a day, six days a week indefinitely - page 152) while the person would not be able to maintain that sort of pace for more than a few hours to a day unless they were in really good shape.
In comparison, typical indefinite marching rates for an army were about 10 miles a day [0catch.com] (both for roman legionaires and US soldiers).
It's very comparable. A human can keep up a 3mph walk forever as well. A 3mph pace is not hard for a human at all and without
a pack 30 miles a day would not be an issue for a human. 35 miles per day, six days a week indefinitely would not be a problem for
the average person either. I don't think a march with camp setup, etc... is comparable to what the original poster was talking about.
I think you underestimate what a human is capable of. When I was in college we went on a hike to the bottom of the grand canyon
for a week. None of us were in great shape, did any training, or probably near as fit as a peasant who worked all day in the field
every day yet we averaged about 20-25 miles a day for a week with heavy packs on rough terrain and making camp each night.
We obviously could have done alot more with a light pack. And again, we were not in shape, didn't train, and most had never even
been backpacking before. For endurance running a human is every bit as good as a single horse. The pony express used multiple
horses because horses are faster over short distances but over multiple days a human is actually faster. A good runner can do alot
more than 35 miles per day. This guy averaged over 50 miles a day for 40 days:
http://www.outsideonline.com/blog/outdoor-adventure/the-human-express-interview-with-karl-meltzer.html [outsideonline.com]
Here is one of many articles that states that humans can outrun every animal on the planet:
http://discovermagazine.com/2006/may/tramps-like-us [discovermagazine.com]