20170814 Reference #1
On this day in 1520, the Magellan Expedition continued a wait for favorable weather at Puerto San Julian.
For the first two months of this period, members of the crew transported supplies from the wreck of the Santiago. The distance overland was about 100 miles, and the journey took four days.
The voyage of exploration resumed on August 24, so there were three months of Southern wintry weather to endure.
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Google provides a "Quick Fact" about the port where the expedition spent the next three months:
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Puerto San Julián is a natural harbour in Patagonia in the Santa Cruz Province of Argentina located at 49°18′S 67°43′W. In the days of sailing ships it formed a stopping point, 180 km south of Puerto Deseado.Wikipedia
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I wondered what the weather might have been like in Magellan's time. It is likely that the expedition log books would have recorded the conditions that the crew endured during the layover, but assuming the weather is comparable today to what it was then, we have this report, from https://www.windfinder.com/webcams/puerto_san_julian
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Wind and weather webcams
Puerto San Julián
Maps Winds 23mph West Temperature 34°F
Report from local weather station at 8:00 am local time.
SUNRISE 8:41 SUNSET 18:30 LOCAL TIME 9:53 am (UTC -3) ELEVATION 62 m
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The purpose of following Ferdinand Magellan and his crew for the duration of their voyage of discovery, 497 years ago, is to secure an anchoring framework for evaluation of alternate futures that might come about in the near or far term.
Analog Magazine's current edition, for July/August 2017, includes a short story by Eve Warren that caught my eye. Ms. Warren presumes that settlement of Mars has succeeded, and that a second generation of native born citizens are succeeding in dealing with the environment. The story, entitled "Teamwork", features an interview of a native young person by a "presumably grizzled" old female military officer who "commands" the settlement.
The element of Ms. Warren's story that I am picking up on today is her mention of use of a means of generating a planetary magnetic field to protect the atmosphere and the biosphere from further predation by Solar radiation and particles. Ms. Warren may have thought of the mechanism herself, or she may be reflecting ideas developed by others, but since this is the first reference I have read to a specific solution, I thought it worth noting.
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When the robots had finished building the solenoid around the equator and radiation flowed around the planet rather than baking its surface, ...
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In thinking about how a permanent magnetic field might be established for Mars, I might have considered a solenoid, but Ms. Warren's depiction of the idea brings it into focus.
While the Earth's magnetic field is reported to be caused by movement of molten material in the interior of the planet, a constructed system on Mars could be optimized for efficiency, as part of a theme of least cost for construction and least cost for ongoing operation and maintenance.
In particular, it seems to me reasonable to suppose the designers might seek to reduce resistance to movement of electrons in the conductors of the "solenoid", and room temperature superconducting physics would certainly help.
(th)