The Story of Astronomy by Peter Aughton Page B

translated into Arabic in the ninth century, but a Spanish version of his work did not appear until the 12th century. It was translated into Latin in the time of Frederick II of Denmark (reigned 1559–88) and thus became available to the majority of European scholars. In the early Middle Ages there was still much interest in astronomy, although there were few active observers. In the monasteries the primary task of the monks was to copy the gospels into Latin and other languages. They occasionally came across scientific manuscripts, however,and sometimes these were also copied. Toward the end of the first millennium we sometimes find chronicles of historical events. The
Anglo-Saxon Chronicle
is a good example: it contains copious references to astronomical events, and when an eclipse or a comet is mentioned it is usually possible to put an exact date to the sighting.
    Thus in the year 540:
“The Sun darkened on June 20th, and the stars showed fully nearly an hour past nine in the morning.”
In 678:
“there appeared the star called a comet, in August; and it shone for three months each morning like a beam of the Sun.”
The chronicle records that in 1066:
“it happened that all through England such a sign as the heavens was seen as no man had seen before. Some men said it was the star ‘Comet,’ that some men called the long-haired star. It appeared first on the eve of Letania maior, April 24th, and so shone all seven nights.”
Visions in the Sky
    The “long-haired star” was literally woven into the fabric of English history when it appeared prominently on the Bayeux Tapestry. Six hundred years later Edmond Halley identified the object as a comet that reappeared every 76 years. A new star appeared a few years before the comet. It was first seen on July 4, 1054, and it was so bright thatfor several months it was visible in broad daylight. Chinese astronomers recorded the event, but there is no mention of it in European records. Nine hundred years later it became identified with a remnant of a supernova (an exploding star) in the Crab Nebula, and for a time it became the most intriguing object in the whole of the night sky.
    Comets and exploding stars are rare events, but changes to the face of Moon are so uncommon that they are virtually unknown. One summer evening in 1178 five English monks were relaxing and staring at the night sky. There was a new Moon, and as they gazed at it they noticed something very strange. A great explosion appeared to be taking place on the Moon before their eyes. The monks knew that the face of the Moon never changed, and so they realized they had witnessed a very unusual event. They did not understand what had happened, but they felt that the event must be a message of some kind from the heavens. They decided to report their findings to a higher authority, and so they made their way to Canterbury where they gained an audience with the archbishop. They swore the truth of their story under oath, and we know a little about the event because it was recorded by the chronicler Gervase of Canterbury (
c
.1141–
c
.1210):
    There was a bright new Moon, and as usual in that phase its horns were tilted towards the east. Suddenly the upper horn split in two. From the mid point of the division, a flaming torch sprung up, spewing out fire, hot coals and sparks.
    The Moon is covered with craters—the result of being regularly struck by objects from space in its long history. It is probable that the monks actually witnessed a large object such as a meteorite striking the Moon. Recent research suggests that the crater named after Giordano Bruno may be the result of the impact witnessed in 1178. (The Earth has suffered similar attacks in the past, but over time the weather has worn all but the largest craters away so that they are far less obvious.)
A Treatise on the Astrolabe
    The Middle Ages are dotted with astronomical observations, but there are no radical new