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November 25, 2009

Mystery of Giordano Bruno Crater

There is a town called Canterbury about eighty kilometers to the southwest from capital city London. The town itself is designated World Heritage but another historical heritage site in town is Canterbury Cathedral. There in the Cathedral is preserved a chronicle of the Middle Ages written by Gervase who was an abbey of the Cathedral. On June 28, 1178 (June 8 in Julian calendar) of the chronicle is described very unusual incident.

Quote
“In this year, on the Sunday before the Feast of St. John the Baptist, after sunset when the moon had first become visible a marvelous phenomenon was witnessed by some five or more men who were sitting there facing the moon. Now there was a bright new moon, and as usual in that phase its horns were tilted toward the east; and suddenly the upper horn split in two. From the midpoint of this division a flaming torch sprang up, spewing out, over a considerable distance, fire, hot coals, and sparks. Meanwhile the body of the moon which was below writhed, as it were, in anxiety, and, to put it in the words of those who reported it to me and saw it with their own eyes, the moon throbbed like a wounded snake. Afterwards it resumed its proper state. This phenomenon was repeated a dozen times or more, the flame assuming various twisting shapes at random and then returning to normal. Then after these transformations the moon from horn to horn, that is along its whole length, took on a blackish appearance. The present writer was given this report by men who saw it with their own eyes, and are prepared to stake their honor on an oath that they have made no addition or falsification in the above narrative.”
Unquote

What does this description of the chronicle mean? A little more than thirty years earlier in 1976, Dr. Jack Hartung, an American planetary scientist, thought that this phenomenon was caused by impact of a gigantic meteorite which produced high temperature dusts and ejecta soared high above in the sky. Viewed in this light, high temperature dusts might have appeared like a flaming torch and low temperature dusts blocked the moonlight to have caused the horn look like split in two or made the moon look like as if throbbing. Dr. Hartung further continued his study to have come to the final conclusion that the meteorite impact site was Giordano Bruno Crater with 20km in diameter located at lunar latitude 36 degrees north and longitude 103 east. Certainly from this crater radially extend long rays, which made the crater look like a very fresh one indeed. However, there has been no evidence to back up this reasoning.

It was the camera division of “KAGUYA” lunar exploration team, who challenged to clear this problem. In the recently issued research paper, the science team of KAGUYA led by Dr. Morota of JAXA is carefully examining the images of Giordano Bruno Crater taken by terrain cameras installed onboard KAGUYA. As a result of studying land features formed of ejecta spewed out of the crater, presence of forty-nine craters, small though, was confirmed on top of the ejecta blanket. Judging from crater density, they concluded the crater is not so young as described in the Canterbury chronicle. Among the craters on moon, Giordano Bruno Crater must be, without any doubt, one of the most recently created craters, but its formation is estimated about five million years ago, therefore, KAGUYA science team concluded that the Crater in question is impossible to be related to the incident described in the Canterbury chronicle.

And then what was that extraordinary phenomenon observed at Canterbury in 1178? Its final answer would be left to future research. After all, however, isn’t it something interesting that Japanese lunar explorer has found a clue as to the mysterious phenomenon recorded in the chronicle of medieval Europe?

Please send your comments, if any, to pscolumn@planetary.or.jp

(Translated by The Planetary Society of Japan)

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