## Saturday, October 09, 2010

### Prague Astronomical Clock: 600th birthday

The Prague Orloj celebrates its 600th birthday these days.

It was completed by clockmaker Nicholas of Kadaň (the town is translated as Capenhagen into Lumo English but only Czech speakers will understand this pun haha - although some clever non-speakers may figure out what's the Czech word for Copenhagen, too) in 1410. Because of the anniversary, the tourists may look into the interior of the gadget now.

These days, the Japanese may produce a replica just for \$1 million and put it into the replica of the whole Old Town Square City Hall in Seoul, South Korea. However, I still find it remarkable that people were able to build similar contrived mechanical devices in the early 15th century, well before the Scientific Revolution.

The Scientific Revolution has changed many things and it has made the progress going but we must realize that the people were not quite incapable morons before it started. Their elite - top 1% of people - arguably knew more about astronomy than the current elites - and maybe even the TRF community - know these days. And they could make 12 disciples of Jesus Christ walk along complicated paths every hour, too. ;-)

They understood geometry well - something that has been inherited from the ancient Greeks. And they understood some kind of mechanics - something you could call Aristotelian mechanics. That's a small perturbation of statics - or perturbation of geometry - which is valid whenever the velocities are really small. A principle of this Aristotelian mechanics says that it's very hard to move anything, and even if you succeed, it stops abruptly unless you keep on working.

In this sense, the Aristotelian mechanics was a science about perfectly inefficient machines. ;-) But because the folks still knew that a heavier object will beat a lighter one on a scale, and that pendulums could work, and a few other things, they could still build many interesting engines.

Meanwhile, in 1410, Mr John Huss was near his top abilities as a critic of the Catholic hypocrisy and other moral defects. He was burned at stake 5 years later, in 1415. It's surely not true that everyone had to be a Dark Ages bigot in the early 15th century. Of course, in Italy and elsewhere, renaissance was already underway. However, Copernicus was only born in 1473, i.e. 63 years after the completion of Orloj.

A night projection showing the history of the Orloj. It starts with global warming and sea level rise, continues with Hussism, a Czech victory in an undetermined war, Peter Parléř's stone work, thermonuclear blast, pictures by Joseph Mánes who made the calendar pretty in the 19th century, detonation on 10/10/10 that gets the skull and the blood out of the stone, and so on. ;-)