The Lord
set the earth on its foundations; it can never be moved. (Psalm 104:5)
Singh,
pp
20,
describes 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
these 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, these 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 fifth 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
these 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 this ‘accurate proposal’ quite plainly disappear for the next fifteen
hundred 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 partly to blame initially; the very idea of the Sun being at the centre of
the universe just ‘seemed ridiculous’
to most people. Add to this, 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 that 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! This decision was
obviously taken on a windless day!
However, far be it for me to interject
.
2.
The Greeks 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’ – then 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 – that 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 these, 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’.
These five non-compliant bodies would present
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 that 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 this conundrum! Slowly but
surely, a complex answer began to evolve.
The final solution to this 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. This 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.
(Of course - there's more to that story as well)
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, that 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.
Once a scholar always a scholar - a great read - thanks :-) Alf
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