Well, owing to the humungus response to my previous post regarding the ancient Greeks (1 comment hehehee) I thought doing another one would be appropriate owing to the fact of over whelming fan mail!

Right, the ancient Greek for today will be an astronomer named Hipparchus. Now the ancient Greeks were pre-occupied with mathematics, the subject, they thought, could answer literally everything, no matter what the problem, a mathematical solution could and would be found to solve it. An ardent supporter of mathematics being the universal panacea was a Greek philosopher Pythagoras, he saw it in music, and envisaged everything being described in terms of mathematical formulae. Spheres and circles of course would be the ideal candidates, readily 3 dimensional and the Moon being right above in the night sky, and local (astronomically speaking) was a perfect body to make mathematical calculations for purposes of measuring distance, so he set about measuring the distance between the Earth and the Moon. This however proved a nightmare! Pythagoras's original conception of how harmonious mathematics would be turned out imperfect numbers in his calculations, the numbers were not the simple ones he imagined would be at the root of everything.

As with all things, you may not discover the very thing you had set out to, but end up discovering something entirely different yet equally important! Enter Hipparchus, he noted that there were several observable facts that did not fall into the category of simple mathematical explanation. One of these was the obvious flaw in the so-called perfect composition of the night sky, he observed that not all stars that shone kept the same regular position as the vast majority did. These 'wandering stars' actually seemed to move independantly to the rest and actually double backed on themselves and would accasionally be brighter or darker in their light intensity. A clue to what Hipparchus was seeing still exists today in our description of the universe, the Greek word for 'wanderer' (planetos) gave rise to the name we still use, he thought he was observing stars, but in fact what he was looking at was a planet, probably Venus, or maybe Mars in a particular close orbit to Earth, and in those ancient times there were probably 5 planets visible to the naked eye.

Painstaking observations enabled the Greeks to plot the courses the planets took, and so duly noted that the paths the planets took were curved, so could they be segments of circles? After this discovery by Hipparchus, It was Plato who encouraged the schools of philosophy to explain how and why these 'wanderers' were adopting an erratic circular path?

Hipparchus had not set out to identify mathematics as a futile vocation, he was just interested in what those odd things were doing in the night sky and thus, discovered the planets. They were already there of course and had been for eons, but his keen nightly observations paved the way for future generations of ancient Greeks to further unravel the puzzle of the cosmos using such techniques as mathematics to prove the universe had a symmetry to it, and so ends another ancient tale of discovery…see you.

With science and religion dominating our perception of life, death, love, and the universe, do any of us really consider where these time immune concepts originated? Whether you are religiously or scientifically minded the ancient Greeks began a multitude of studies that are still in practice today. It was the ancient Greeks who began philosophical, scientific, and theological studies in order to explain the unexplainable when looking at the night sky.

One such ancient Greek, a mathmetician named Eratosthenes pondered the significance of the universe and his place in it, he would gaze (it is said) at the night sky and after a while he would notice things which unknown to him at the time was destined to shape our modern-day understanding of our planet as a sphere. The ancient Greeks as a whole noticed that the night sky, as seen from Samos and from Alexandria had the same stars but where in a different position? It is not noted how they traversed the distances between the two places to make these observations, but the ancient Greeks were great sailors, so we can assume they did drawings from one place and the other then made comparisons.

This story claims… Eratosthenes noticed that a stick, when planted in the ground would cast different shadows at different times of the day, and with the sun directly overhead would cast virtually no shadow at all, and at dusk or dawn the shadow would be at its longest. Eratosthenes observed two sticks of equal length one in Aswan and one in Alexandria at the same time of day, it is also unclear how he did this but maybe a friend helped him with his studies, or maybe Eratosthenes himself visited both places and made observations at the same time of day but on different days, whichever it was is not that important but what is important where his findings. He noticed that the two shadows cast by the sticks, at the same time of day, were of different lengths!

Now at this point, Eratosthenes considered what this revelation meant for his research and gained a remarkable insight. The two sticks had been carefully placed upright, and at right angles to the Earth, so if the Earth was flat as it was percieved to be in the ancient world, he reasoned that the two sticks would be parallel to each other, and since the sun is so far away, the rays of light travelling to each stick would also be parallel, so if the Earth was indeed flat, both shadows would be the same length at any one time of day, but this was not the case. This was simple elementary geometry in action, if the sun, on a flat Earth, was shining directly over one stick and casting no shadow, you would expect the same outcome with the other stick, and so cast no shadow? But on the other stick Eratosthenes recorded that a very clear shadow had been cast. His further studies showed that the two sticks would always cast different length shadows at any given time of day.

These findings were pointing at only one possible answer, and Eratosthenes concluded that although the two sticks were both at right angles to the Earth's surface, they were not parallel to each other, and that could only happen if the Earth's surface was curved. To be fair, the Greeks had long suspected the Earth's surface to be round, and Eratosthenes experiment did much to prove this theory.

Apart from all the other things the ancient Greeks began, reasoning through mathematics and logic would prove timeless for mankind, the quest for a greater understanding of the universe had begun, and Eratosthenes could be considered a pioneer, he had established a template for investigation, a basic method that science could apply in its geometrical studies. Eratosthenes did many more things with 'Euclid's' mathematical elementary geometry but above all he had proven beyond reasonable doubt that our planet, our home, was indeed round.

Another Greek tale later…JDA.