Up in the Air

Was a solar cycle factor in Jamestown cannibalism?

May 19, 2013 

Daniel B. Caton is a physics and astronomy professor and director of observatories at Appalachian State University.

Cannibalism in Jamestown colony! The recent news of evidence of human skulls with scrape marks that anthropologists know are from tools suggests that times were so desperate in the winter of 1609-1610 that the last survivors resorted to the worst of crimes.

That winter fell in the middle of the Little Ice Age, an unusually cold period lasting from around 1350 to the dawn of the industrial age – around 1850. After that, human-caused climate change added the famous “hockey stick” spike to the current global temperatures graph, masking the natural effects, perhaps forever. The Little Ice Age was a brutal time, with crop-killing springs, summer frosts and deadly winters. A couple of successive failed growing seasons, and you were dead.

Meanwhile, Galileo was about to turn his telescope to the heavens in 1610. That work would include some of the first telescopic observations of sunspots, areas on the sun that are 1,000 or more degrees cooler than the rest of the sun’s surface and thus appear dark by contrast.

After a few decades, though, the spots disappeared for half a century, until about 1700 – a period called the Maunder Minimum, and centered in the middle of the Little Ice Age. This was not a lack of data – there were observers looking – but a lack of spots. We will never know what the sunspot count was in that fatal winter of 1610, before the invention of the telescope. But there were only a couple of normal 11-year sunspot cycles observed before the MM period began. That Jamestown winter could have been a low-count year.

Warmer times on Earth coincident with the sun’s being covered with cool spots seem paradoxical. But the sun’s output may be less when spot-free for reasons not yet understood.

Only recently, with spacecraft observations, have we learned that the output of the sun varies more than previously thought and that interactions of varying solar ultraviolet light with Earth’s atmosphere may affect our weather in subtle ways.

But we have no idea why it happens at all!

Solar physics is messy stuff, with trying to model the hydrodynamics of gases that interact with varying magnetic fields. Indeed, the cause of the basic 11-year sunspot cycle itself is still debated.

Could we have another Maunder Minimum? Maybe so, the current cycle, Cycle 24, started late and looks to be approaching the lowest peak since Cycle 14 in 1906.

And frosts can still kill crops, which we and our feed animals depend on.

Piece of scalp, anyone?

Daniel B. Caton is a physics and astronomy professor and director of observatories at Appalachian State University. Email: catondb@appstate.edu. More on this month’s column: www.upintheair.info.

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