The Guardian reports that recent scientific experiments confirm the use of Icelandic spar (a type of calcite) may have enabled the vikings to navigate without a compass even in cloudy weather. Apparently this stone is described in an Icelandic legend about a sailor called Sigurd, who used such a stone on a cloudy day to orient his ship. This may explain how the vikings were able to sail to America even in polar gloom. An interesting side point of the research is that, apparently, even a single cannon on an Elizabethan ship held enough iron to interfere with a compass, and sunstones may have been used by navigators to avoid this effect 4 centuries after the end of the viking era.

Of course the vikings knew nothing about the polarization of light or even the scientific processes by which instruments are calibrated and used. How did they discover this “magic” property, how did they believe it worked, and what did it tell them about the world around them? This kind of solution to complex navigation problems fascinates me as an example of science in an era when many phenomena of the natural world must surely have been seen as magic. Probably, the vikings had worked out sophisticated navigation techniques without any understanding of the nature of the heavens or the earth. It’s interesting to think about how far such science takes people before it breaks down or its contradictions force its adherents to find modern science. How do these processes work…?