A Brief History of Time (II)

2010.04.21

To Whom It May Concern:
Another week has passed. I should be completed with my book. The entire eleven chapters of A Brief History of Time: from the big bang to black holes need to be completed. From the last letter of 2010.04.14, I have completed minimal reading…again. I think this week I took a step backward compared to my previous progress. Then again, I did not have much time to read my book. It was a very busy weekend. And of course my weekday nights are hectic. Nevertheless – I still accomplished some reading.

In 340BCE ., Greek philosophers (namely Aristotle) started in depth studies of astronomy. Prior this time, most studies concerning the sky and space was astrology based. Now Greek philosophers started studying the round shape of the earth (and other heavenly bodies) and the patterns of their orbits. Although some predictions were incorrect, it was the first major step in understanding more about the universe in this scientific perspective.

By the second century C.E., the set of observations thus far were compiled into their complete cosmological model. The earth stands stationary in the center of the universe. Surrounding it orbit in circles that carry the moon, the sun, the stars, and the five known planets at the time: Mercury, Venus, Mars, Jupiter, and Saturn. For some reason, ancient scientists think that for some reason –mystical, religious, or imaginative – that the earth was the center of the universe. The outer-most orbit consists of “fixed stars” – which always stay in the same position relative to each other but which rotate together across the sky as a whole. Beyond these fixed stars remained a mystery. It was by far beyond the observational power of the most advanced technology at the time.

However, Ptolemy (who added the final touches of that cosmologic model) recognized that the model was flawed. In order to predict the positions of the heavenly bodies correctly, it had to be assumed that the moon followed a circular orbit while somehow bringing it twice as close to the earth as at other times. Therefore, the moon technically could not form a circular orbit for his calculations. On top of that, the moon ought to have appeared twice as large as it did other times.

Albeit flawed, this model was adopted by the Christian church as the structure of the universe – as it was in accordance with the writings. The outer “fixed stars” sphere also allowed room for the Christian church to fix ‘heaven’ and ‘hell’.

For the most part, this flawed model was accepted. In 1514, Polish priest Nicholas Copernicus suggested that the sun was stationary and the center of the universe. Consequently, the earth and the planets moved in circular orbits around the sun and the moons (or other smaller bodies) can orbit other planets. This theory accounts for the fact that the visible moons of Jupiter did not regularly orbit the earth, but orbited in an irregular (and somehow complicated) patter around the sun.

In sum, what does that tell me? Regardless of how many times a theory is proposed, it is still possible that it requires modification or discarding altogether. We can only assume what are the patterns and forces of nature, and even after numerous years of observation, there is still more to discover about our universe.