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2018 ; 5
(4
): 172187
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Success of sky-polarimetric Viking navigation: revealing the chance Viking
sailors could reach Greenland from Norway
#MMPMID29765673
Száz D
; Horváth G
R Soc Open Sci
2018[Apr]; 5
(4
): 172187
PMID29765673
show ga
According to a famous hypothesis, Viking sailors could navigate along the
latitude between Norway and Greenland by means of sky polarization in cloudy
weather using a sun compass and sunstone crystals. Using data measured in earlier
atmospheric optical and psychophysical experiments, here we determine the success
rate of this sky-polarimetric Viking navigation. Simulating 1000 voyages between
Norway and Greenland with varying cloudiness at summer solstice and spring
equinox, we revealed the chance with which Viking sailors could reach Greenland
under the varying weather conditions of a 3-week-long journey as a function of
the navigation periodicity ?t if they analysed sky polarization with calcite,
cordierite or tourmaline sunstones. Examples of voyage routes are also presented.
Our results show that the sky-polarimetric navigation is surprisingly successful
on both days of the spring equinox and summer solstice even under cloudy
conditions if the navigator determined the north direction periodically at least
once in every 3?h, independently of the type of sunstone used for the analysis of
sky polarization. This explains why the Vikings could rule the Atlantic Ocean for
300 years and could reach North America without a magnetic compass. Our findings
suggest that it is not only the navigation periodicity in itself that is
important for higher navigation success rates, but also the distribution of times
when the navigation procedure carried out is as symmetrical as possible with
respect to the time point of real noon.
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