Chapter 6 - Coming Full Circle

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        Chapter 6 - Coming Full Circle

 

The Lord set the earth on its foundations; it can never be moved.

(Psalm 104:5)

                     

 

Whilst the subject of this chapter may seem familiar, the logic behind the ideas may not be as obvious.  Our modern conceit ensures ‘we know’ how the universe is structured and are confident in our summation because our technology and scientific know-how supports our theories beyond a shadow of doubt. 

Singh, pp 20, described how our ancestors studied the sky by night and day to determine changes in weather patterns, measure time, and confirm directions.  The ground on which they stood stayed firm under feet and the heavens passed overhead in an endless and ‘fairly predictable’ procession; consequently, they assumed the Earth was the centre of the ‘known universe’ and the heavens revolved around it and them.

 

Notwithstanding those early, Earth-centred assumptions, there were a few early thinkers who quite accurately proposed a heliocentric (sun-centred) ‘universe’.  Whilst the idea of our solar system as just a tiny part of the greater universe was still a long way off, those early heliocentric proposals were uncannily correct.   Here we can observe yet another perfect example of human knowledge and ideas being built upon �" handed down �" and developed over several generations.   The earliest recognition for presenting a ‘true’ heliocentric model goes to Aristarchus of Samos (310 BC-230 BC); however, it is acknowledged that his proposals were based on the ideas of those who had gone before him. 

 

Philolaus of Croton (approx 470 BC�"385 BC) a pupil of the Pythagorean school, in the 5^th century BC, was possibly the first to suggest the Earth orbited the Sun.  In the following century, Heraclides of Pontus (approx 387 BC-312 BC) developed those ideas even further.  For his efforts, he was publically ridiculed, labelled crazy and given the nickname of Paradoxolog �" ‘the maker of paradoxes’. 

 

 

Whilst there is some disparity about the dates given from various sources, it is clear that Aristarchus was born about the time of Heraclides’ passing.  Naturally, any of the aforementioned characters are worth further investigation if the reader is so inclined.  It goes without saying; their lives were a rich mosaic of mathematical and philosophical thought.  Truly �" no man is an island!

 

Having established a viable and reasonably accurate model of a heliocentric ‘universe’ what happened to change that model?  Why did such an ‘accurate proposal’ quite plainly disappear for the next 1,500 years, until resurrected in the early 1500s by Nicolaus Copernicus, and later, in the face of severe religious persecution, brought to the fore by Galileo Galilei?

 

Change doesn’t occur easily in the human intellect �" egocentrism rules �" and the majority, especially if supported by religious or mystical factions in society, tends to hold sway against even the most persuasive scientific arguments.  It appears our old companion �" common sense �" was initially partly to blame; the very idea of the Sun being at the centre of the universe just ‘seemed ridiculous’ to most people.  Add to that, the ‘fact’ that the heliocentric model did not stand up to rudimentary scientific analysis and did not appear to reflect reality.  Three very specific criticisms appear to have been levelled:

 

1.    The Greeks reasoned - if the Earth moved rapidly through space �" they would feel a great continuous wind pressure blowing against them.  The Earth, they concluded must be motionless!   That decision was obviously taken on a windless day!  However, far be it for me to interject. 

2.    The Greek’s inability to appreciate the effects of gravity in the sense that, to them, everything naturally moved towards the centre of the universe.  Apples fell from trees, stars were seen to ‘fall’ from the sky, and so, as everything ‘fell to earth’, it followed Earth MUST be the centre of the universe.  If the Sun were at the centre of the universe, it was fairly obvious to the ancient Greeks, everything would ‘fly up’ and off in the direction of the Sun.

 

3.    The third reason given is more understandable in that a lack of instrumentation or technology rather hindered the Greek ability to identify any shift in the positions of the stars.  The stellar parallax �" as it is more familiarly now understood - indeed could not be detected with the naked eye, simply because of the vast distances involved.

(See: http://onlinedictionary.datasegment.com/word/stellar+parallax)

 

There were however, five celestial bodies that seemed to defy the observations at point 3 above, and those, as we now know, were the five known planets:  Mercury, Venus, Mars, Jupiter and Saturn.  For those who love trivia, the word ‘planet’, originated from the Greek, planetes­, meaning, ‘wanderer’.  Those five non-compliant bodies presented problems that would eventually be overcome by sheer human resourcefulness, or determination to appear correct at any price!  Quite simply, one of the core issues in the heliocentric debate was; if the heavens orbit in circles around the Sun, then it followed there would be an obvious predictability in the patterns produced in the cosmos.  The patterns did not appear to concur with the hypothesis.

 

Over the course of several centuries many astronomers and mathematicians contemplated the conundrum!   Slowly but surely, a complex answer began to evolve.  The final solution to the problem became associated with the astronomer, Claudius Ptolemy (AD 90-c. AD 168).  Ptolemy’s, astronomical paper on the intricate movements of the stars and planetary paths, the Almagest, is known as one of the most significant scientific documents in human history.  So powerful was Ptolemy’s argument, it held sway from its origins in Hellenistic Alexandria, into the Byzantine and Islamic cultures and on into Western Europe through the Middle-Ages and early Renaissance up until the time of Copernicus! 

 

One glance at a model of the Ptolemaic system reveals a system so complex as to be almost unbelievable.  Part of the problem that had to be overcome was caused by Mars and the outer planets, which, to observers on Earth, appeared to move sometimes ahead, at other times stop completely, and yet again at other times, to move backwards. 

That apparent anomaly was simply a result of Earth’s position within the solar system and our respective orbits around the Sun.  However, to make the ‘mathematical facts’ fit the geocentric model; Ptolemy devised a complex, but workable solution, known as the epicycle!                         (See: http://www.thefreedictionary.com/epicycle)

 

The analogy provided for this model compares to a wild fairground waltzer ride, in which the passenger is locked into a cradle joined to a long arm. Whilst the cradled passenger follows a small ‘circular orbit’ the longer arm at the same time describes its own much larger ‘orbit’.  This complex arrangement complied with the demands created by the Earth-centred model and satisfied both science and religion at that time.

 

Of course, such blatant manipulation of reality is not the sole province of the ancients; in more modern times, Einstein’s cosmological constant was an equally blatant mathematical mirage designed to suit the ‘required populist truth’.  Luckily for Einstein, he got to make amends for his moment of weakness in his rush to comply with the wishes of the ill-informed majority.

 

As for the Ptolemaic system, the only tweak required to commit it to the garbage bin of magnificent human mirages was a slight adjustment to orbital physics.  The most basic mistake made in the first place by those who anticipated the heliocentric model, was to base their assumptions on perfect 360° ‘divine circles’.  In doing this, those heavenly bodies that wandered the night skies and should have had predictable orbits, were not where they were supposed to be at the appointed season!  In fact, if the orbits are based upon the true elliptical paths taken by the planets in our solar system, then we know with certainty, those objects will unfailingly appear at the predicted times.

 

 

Refs:

Encyclopedia, W. T. F. (2011, March 1). Almagest. Retrieved April 4, 2011, from Wikipedia: http://en.wikipedia.org/wiki/Almagest.

Encyclopedia, W. T. F. (2011). Aristarchus of samos. Retrieved April 5, 2011, from Wikipedia: http://en.wikipedia.org/wiki/Aristarchus_of_Samos.

Encyclopedia, W. T. F. (2011, March 1). Ptolomy. Retrieved April 4, 2011, from Wikipedia: http://en.wikipedia.org/wiki/Ptolemy.

Singh, S. (2005). Big bang. London: Harper Perennial.

Stamatellos, G. (1997). Philolaus of croton. Retrieved April 5, 2011, from philosophy.gr: http://www.philosophy.gr/presocratics/philolaus.htm.