NASA tells us that “Comets are cosmic snowballs of frozen gases, rock and dust roughly the size of a small town. When a comet's orbit brings it close to the sun, it heats up and spews dust and gases into a giant glowing head larger than most planets. The dust and gases form a tail that stretches away from the sun for millions of kilometers.” This image depicts Halley’s Comet (which is featured in the Bayeux Tapestry). Named for a famous scientist who predicted its return, Halley’s Comet takes about 76 years to orbit the Sun. Image credit: ESA / Max-Planck-Institute for Solar System Research.
Harold II was crowned king of England on the 6th of January, 1066 - soon after Edward the Confessor (Britain's next-to-last Anglo-Saxon King) died without children, leaving his succession in dispute. In the spring of that year, the Anglo-Saxon Chronicle (Part 5) records that a “comet-star” shone for a week:
A.D. 1066. ...Then was over all England such a token seen as no man ever saw before. Some men said that it was the comet-star, which others denominate the long-hair'd star. It appeared first on the eve called "Litania major", that is, on the eighth before the calends off May; and so shone all the week.
Some of the people took this as a bad omen: Maybe Harold wasn’t the rightful king after all?
The Bayeux Tapestry, a beautifully embroidered history completed in the eleventh century, memorializes this sense of awe and foreboding. In one panel (look at the bottom right), we see the “long-hair’d star” and this description: ISTI MIRANT STELLA - Latin for “They are seeing the star” (or "These [people] look in wonder at the star").
We also see the king’s attendant, who has rushed to tell Harold about the celestial sighting.
What do the pictures mean? Harold - according to the French perspective - knows he broke an oath to William, Duke of Normandy. He’d promised William to support his claim to the throne of England on the death of King Edward the Confessor (William’s distant cousin).
We know, of course, that the Duke of Normandy - William the Conqueror - did invade his neighbor to the north, defeating Harold and his exhausted troops in the 1066 Battle of Senlac Hill (near Hastings), thereafter becoming King William I. History - and the tapestry - record the events. (See the hand-embroidered tapestry “come alive” in narrated animation.)
We also know something else. Seven centuries later, Edmond Halley accurately predicted the return of a comet in 1758. His work, A Synopsis of the Astronomy of Comets, together with subsequent studies, led scientists to conclude the unusual star of 1066 was Halley’s Comet, making one of its rare appearances.
Throughout recorded history people were fascinated by (and fearful of) comets whenever they appeared in the sky. Around 300 B.C., Chinese astronomers compiled the "Mawangdui Silk" which depicts various comet forms and their associated disasters. Halley’s Comet became so closely associated with disasters that - it is said - Pope Calixtus III actually excommunicated its apparition in 1456.
Many comets appeared during the seventeenth century, and artists created images of them. Let’s look at a few examples.