BDanielMayfield wrote: ↑
Sun Sep 06, 2020 11:50 am
The explanation's link to 1054 AD's first paragraph says this:
On July 4, 1054 A.D., Chinese astronomers noted a "guest star" in the constellation Taurus; Simon Mitton lists 5 independent preserved Far-East records of this event (one of 75 authentic guest stars - novae and supernovae, excluding comets - systematically recorded by Chinese astronomers between 532 B.C. and 1064 A.D., according to Simon Mitton). This star became about 4 times brighter than Venus in its brightest light, or about mag -6, and was visible in daylight for 23 days.
Therefore astronomers are quite confident we know exactly when the Supernova that created the Crab Nebula occurred. However, the above link also says this:
Strangely enough, it seems that at least almost no records of European or Arab observations of the supernova have survived to modern times.
Surely a "new star" so bright it could be seen during the day would have been noted in Europe, north Africa and the Middle East. I'm guessing we can thank
blame the Crusades and the Dark Ages for this glaring omission from western history.
Not the Crusades. They didn't begin until 1095. It's hard to say what the explanation is because this is the beginning of the High Middle Ages when Europe is beginning to recover, and in addition, the Muslim world was in its golden age of art and science, with some of the most famous Arab astronomers working during this time. One possibility is that, because of the scientific understanding of the time (a geocentric universe which is perfect, eternal and unchanging, thanks to Aristotle), something like that would be less likely to be noticed for what it was. This happened more than once in history. The planet Uranus was observed multiple times before William Herschel "discovered" it. However, it was marked down on earlier star charts variously as a comet (seen as a meteorological event) or simply a star that hadn't been noticed before. Why? Because they knew how many planets there were. The idea that there could be more was ludicrous.
But other supernovae were recorded in Europe. In 1006, there was a supernova that was observed around the entire planet. We have sources from nearly every continent. A few hundred years later, Tycho Brahe and Johannes Kepler were both fortunate enough to observe supernovae.
But it could also simply be the vagaries of what gets preserved. We have original texts going back thousands of years, but we also have lists of works written by famous philosophers that we've never been able to read because, for whatever reason, those didn't get preserved. For example, we actually don't have Aristotle's works. We have the equivalent of lecture notes. We know that he published works, but they didn't get preserved. That makes historians wonder if we really know what Aristotle said in his philosophy or if we have someone else's interpretation of what he said. Such are the frustrations of history.
There's your mini lecture for Sunday morning.