Sunday, December 12, 2004

Wonders and portents

It is the morning of July 5, 1054 A.D. You wake to a thin crescent moon between the horns of Taurus the Bull, low in the eastern sky. And nearby -- wonder of wonders -- a brilliant new celestial object, apparently a star, but shining more brightly than any star you have ever seen, four times brighter than Venus, so bright that for the next several weeks it will be visible even in daylight.

The new star slowly fades. Within a few years it is gone.

The new star of 1054 was visible from pretty nearly every inhabited part of the globe. Chinese observers recorded it. Japanese and Arabs too. It is hard to imagine that anyone able to rise from their bed might have missed it.

We now know that the blazing light in the sky was a supernova -- the explosive death of a massive star too far away to have been previously visible to the unaided eye -- one of only a dozen or so of these rare celestial events that were recorded by human observers before the advent of telescopes.

Today, if we turn our telescopes to the place between the Bull's horns where the new star appeared, we see the shattered remnants of the progenitor star, still racing outwards, called (from its shape) the Crab Nebula.

It has always been something of a mystery why no European records of the supernova have been found. Surely so spectacular an event must have attracted wide notice, especially among a people obsessed with religious superstition. It was, after all, not so many years after the turn of the millennium, when many Christians expected the end of the world.

It turns out that the supernova may have a European record after all. I thank Gerry Wrixon, president of Ireland's University College Cork -- and a radio astronomer -- for drawing my attention to an article published in 1997 in Peritia, the journal of the Medieval Academy of Ireland.

Daniel McCarthy, a computer scientist, and Aidan Breen, a scholar of Celtic studies surveyed Irish monastic records from the coming of Christianity in the 5th century to the dissolution of the monasteries in the 16th century, compiling an inventory of astronomical and meteorological observations.

They found nearly 100 relevant notations, including observations of eclipses, comets, and extraordinary auroral displays. Two entries record clouds of dust (from Icelandic volcanos) that colored and obscured the sky. An annal entry in the year 1054 is interpreted by McCarthy and Breen as a record of the supernova.

The pertinent 1054 entry states: "A round tower of fire was seen in the air over Ros Ela on Sunday the feast of S. George for five hours of the day."

It takes a stretch of the imagination to connect this short passage with a supernova. The relevant part, according to McCarthy and Breen, is that something fiery was seen from a certain identifiable place for five hours in daylight.

Ros Ela is a townland near the ancient monastic site of Durrow, in County Westmeath, and the supernova would indeed have appeared over that place as observed from the monastery.

As for the "round tower of fire" and the spurious date (the feast of St. George is April 24), these appear to be later interpolations into the record for the sake of connecting the celestial event to the Coming of the Antichrist as predicted by Revelation.

The "tower of fire" presumably represents the scriptural "great star...blazing like a torch" (Revelation 8:10), and St. George would have been a logical warrior hero to confront the demon horde. The fanciful passage that follows the presumed reference to the supernova evokes an apocalyptic vision.

Slight evidence, indeed. But the Irish annalists proved themselves to be observant and generally accurate with their recordings of eclipses and comets, most of which can be checked using modern astronomical computation. It would have been puzzling if they failed to note what must have been the most spectacular apparition of all.

For the monks of 11th-century Ireland, these extraordinary celestial events were interesting primarily as apocalyptic signs and portents to be interpreted within a scriptural context.

Anticipation of the End Times has been a perennial preoccupation of certain superstitious Christians -- no less today than in the Middle Ages, as witnessed by the hugely popular Left Behind series of novels. Nature will never fail to provide omens and portents to a mind predisposed to believe.

Further Reading

Daniel McCarthy and Aidan Breen, Astronomical Observations in the Irish Annals and Their Motivation, Peritia: Journal of the Medieval Academy of Ireland, Volume II, 1997, pp. 1-43. The authors' discussion of the total solar eclipse of May 664 and its effect on the Synod of Whitby is exceedingly interesting for church history.

The most complete scholarly survey of historical supernovas is David H. Clark and F. Richard Stephenson, The Historical Supernovae (Pergamon, 1977). But for general reading, try Clark's more accessible Superstars: How Stellar Explosions Shape the Destiny of Our Universe.

You can watch a ten-second Hubble movie of the Crab Nebula here.

The best-selling books for adults in America are the apocalyptic Left Behind series by Tim LaHaye and Jerry Jenkins. They were brilliantly critiqued by New York Times columnist Nicholas D. Kristof, on November 24, 2004. The archived article, Apocalypse (Almost) Now, on the Times website is available by subscription only, but the column is not hard to find with Google. Kristof closes with this deal: "So I challenge the authors to a bet: if the events of the Apocalypse arrive in the next 10 years, then I'll donate $500 to the battle against the Antichrist; if it doesn't, you donate $500 to a charity of my choosing that fights poverty - and bigotry." Seems like a piddling offer to me. I'll make the same bet for my entire net worth. After all, if Jesus comes on a cloud of glory and casts me, my family, Kristof, Jews, Moslems, Hindus, Buddhists, and everyone else who is not a born-again Christian into the fires of everlasting torment, as LaHaye and Jenkins earnestly profess, I won't need money, will I?

For a few centuries after the arrival of Christianity in Ireland in the 5th century, Irish scholars were rather less superstitious about natural events that the annalists of the 11th century. See my Climbing Brandon: Science and Faith on Ireland's Holy Mountain (under Books).

Student Activities

  1. It's great fun to explore celestial events of the past and future with sky simulation software. The program I use is called Starry Night Pro, and with it I can see exactly what the morning sky looked like from Durrow in Ireland on the morning of July 5, 1054. A great investment for any school.
  2. What can you discover about the supernovas of 1577 and 1604? Why are they called Tycho's Supernova and Kepler's Supernova?
  3. We are overdue for a bright supernova on our side of the Milky Way Galaxy. Historical supernovas occurred about every 200 years on average, and the last was in 1604. It could happen tonight!
  4. When a star sheds some outer layers rather than blasts itself apart, it is called a nova. Novas are more common, but not as spectacular as supernovas. There has been only one conspicuous nova during my adult life. In August 1975 a new star blazed for one glorious evening in the constellation Cygnus, almost at bright as the nearby star Deneb -- like a feather plucked from the Swan's tail.

Discuss this essay and more over on the Science Musings Blog.