Observations of a blown mind

Posts tagged “Cosmos

Science and early Christianity

Over the last thousand years Christianity has adopted many things from other religions, but it also took from science too.

A Spherical Harmony

The earliest ancient civilizations all shared the same fundamental view of the universe; that our earth lay at the centre. The characteristically inventive Sumerians of what we now call Iraq; the Amorite dynasty that founded the Babylonians; and also the North East African civilisation of the ancient Egyptians; all these ancient civilizations had the Sun, Moon, stars, and planets revolving around us. The specific explanations varied from society to society, but the viewpoint that came to dominate the minds of Europeans was established by successive generations of the ancient Greek philosophers. Though I say “ancient greeks”  they were in reality learned philosophers who lived across many centuries with their theories of the cosmos being somewhat refined over a time period scanning more than six hundred years.

Te first known idea of the stars being fixed to a sphere, or hemisphere, rotating around the earth is attributed to Anaximenes of Miletus, who lived in the 6th century BC. Like his predecessors, Anaximenes was preoccupied with cosmology, searching for the world’s origin in which he is most known for his assertion that air is the most basic and originary material and the source of all things. While empirical evidence was essential in Anaximenes’ work, the less evidentiary notions of the divine remained apparent as well. Perhaps in line with early Greek literature that rendered air as the soul, as in the ‘breath of life,’ Anaximenes relates air with god and the divine, according to the accounts of Aetius. The qualities of air, that has similar attributes as the qualities of Anaximander’s aperion, are those of the divine and the eternal. It is posited, by Aetius and later by Cicero, that there is a strong correlation between the notion of air as an originary principle element and the notion of air and breath as the divine and eternal substance of the soul and of god.

In the 6th century, Anaximenes of Miletus, saw the Earth as a kind of flat disc, or a flat-topped cylinder that floated like a cork in the air. Pythagoras of Samos – the same Pythagoras whose theory we use today to calculate the area of a triangle – changed the disc to a globe then placing it at the centre of concentric spheres, one for the Sun, the Moon and each of the planets, with the other stars ‘fixed’ at the furthest distance. For Pythagoras, the physical distances separating the spheres was of great importance, even seeing the seven planetary spheres (Moon and Sun included) and the shpere of the stars being separated in the same seven ratios as those of the musical scale. It was this particular notion that gave us the concept of the “harmony of the spheres” that was to resonate for two milennia.

The model that later became fixed stemmed from a proposition laid down by the philospher and methematician Plato circa.  400 BC. For Plato, the circle was the perfect form and he was totally convinced that the Sun and the Moon revolved around a spherical Earth in circular orbits. Plato’s students were left with the challenge of  creating a model that explained his philosophy. Eudoxus of Cnidus offered an ingenious solution of multiple concentric spheres. The orbit of our Moon illustrates this idea; to explain its apparent movement through the heavens the Moon needed three spheres; one rotating every day in order to explain the rising and setting; a second rotating every month in order to explain the movement through the zodiac (movement against the stars); and a third rotating monthly on a slightly different axis in order to explain its variation in latitude. To see Eudoxus solution click here.

The problem that was obvious to the ancient astronomers was that planets behaved in a strange fashion, sometimes they were closer, sometimes farther away from Earth, sometimes speeding up and sometimes slowing down or even appearing to travel backwards. The word “planet” comes from the Ancient Greek word for “wonder”. Our friend Eudoxus required 27 concentric spheres to explain the movements in the heavens, but that was later refined by his contemporary, the great philosopher Aristotle, in to a model of greater perfection. In an attempt to make sense of what was observed, he placed 55 concentric spheres around the Earth, each responsible for a specific movement of the heavenly bodies, always though in the perfect eternal motion of a circle, as they passed through the substance out there that he called the “aether”. At the furthest extremities he placed the “Unmoved Mover”, or the force that centuries later came to represent the all-powerful Christian God.

All this could have, and should have, been rendered irrelevant had the ideas of Aristarchus, also of Samos, caught on some 200 years later! Essentially he had it all worked out. He placed the Sun at the centre of the cosmos, with the Earth and other planets circling it, in the same order as we know them today.

Image credit Wikipedia Commons

Image credit Wikipedia Commons

But his theories did not stand up to the withering logic of the time. He was unpicking the established teachings of the great Aristotle and Plato. Yet it didn’t gain kudos because it seemed so self-evidently wrong. If indeed the Earth were moving through space, why would an object thrown upwards come straight back down? Surely it would land at a distance away as the ground the individual were standing on moved through space. So, the common sense of the time indicated that Aristotle had it right.