The Dark Ages - Were They Darker Than We Imagined

As we approach the end of the Second Millennium, a review of ancient history is not what you would normally expect to read in the pages of Universe. Indeed, except for reflecting on the AD 837 apparition of Halley's Comet (when it should have been as bright as Venus and would have moved through 60 degrees of sky in one day as it passed just 0.03 AU from Earth - three times closer than Hyakutake in 1996), you may well wonder what we could learn from any astronomical events that occurred more than a thousand years ago.

Any history text will say that the Dark Ages refers to the period after the fall of the Roman Empire in the middle of the 1st Millennium (it was not sponsored by the International Dark Sky Association). It was a time when European civilisation stagnated - even that term is a generous description of the living standards and social setting of the next few centuries. In a broader sense, however, "Dark Ages" can be applied to a few eras of social upheaval over the last several thousand years, which fits in nicely with what you're about to read - stay with me, as the possible astronomical implications will soon become apparent.

Physical Aspects Of The Dark Ages

Let's first look at the onset of "the" Dark Ages in the sixth century AD. The Roman Empire was finished, nothing was happening in the sciences, and worse was happening in nature. The Italian historian Flavius Cassiodorus wrote about conditions that he experienced during the year AD 536 :

"The Sun...seems to have lost its wonted light, and appears of a bluish colour. We marvel to see no shadows of our bodies at noon, to feel the mighty vigour of the Sun's heat wasted into feebleness, and the phenomena which accompany an eclipse prolonged through almost a whole year. We have had a summer without heat. The crops have been chilled by north winds, [and] the rain is denied."

Other writers of the time described similar conditions :

Procopius : "...during this year a most dread portent took place. For the Sun gave forth its light without brightness...and it seemed exceedingly like the Sun in eclipse, for the beams it shed were not clear."

Lydus : "The Sun became dim...for nearly the whole year...so that the fruits were killed at an unseasonable time."

Michael the Syrian : "The Sun became dark and its darkness lasted for eighteen months. Each day it shone for about four hours, and still this light was only a feeble shadow...the fruits did not ripen and the wine tasted like sour grapes."

Was this a local phenomenon? According to the book "Volcanoes of the World", Dr. Timothy Bratton has noted that there was a small eruption of the volcano Mt. Vesuvius in AD 536. Could this be the cause? It may well have contributed to the scene (although the eruption was much smaller than the big one of AD 79), but it can not really account for the similar conditions that were experienced around the world.

In China, "the stars were lost from view for three months". Records indicate that the light from the Sun dimmed, the expected rains did not eventuate, and snow was seen in the middle of summer. Famine was widespread, and in the midst of the turmoil, the Emperor abandoned the capital.

Bad luck tends to get bunched together, and thus came the plague. The Justinian Plague, named after the Byzantine Emperor of the time, is reported to have begun in central Asia, spread into Egypt, and then made its way through Europe. By some accounts, it was as bad as the Black Death which "plagued" Europe in the Middle Ages.

A Different Branch Of The Picture

Mike Baillie is Professor of Palaeoecology at Queens University, Belfast, Northern Ireland. He is an authority on tree rings and their use in dating ancient events (every year, a tree adds a "ring" to its trunk as it grows - good years are represented by thick rings while bad years are represented by thin rings). He conducted a complete (and continuous) review of annual global tree growth patterns over the last 5,000 years and found that there were five major environmental shocks that were witnessed worldwide. These shocks were reflected in the ring widths being very thin. Wanting to know more, he turned to human historical records, and found that the years in question (between 2354 and 2345 BC, 1628 and 1623 BC, 1159 and 1141 BC, 208 and 204 BC, and AD 536 and 545) all corresponded with "dark ages" in civilisation.

The minimal growth of trees around 2350 BC has been associated in the past with the eruption of a volcano in Iceland. Yet, the period in question is also associated with floods,