A Bit of Astronomical History & its People

A short time ago in a galaxy quite close by...the Earth was flat. Flat and square. Then it became flat and round, like a DVD. Along came the Greeks who wanted to know just what was going on with all they could see around them as well as what was up in the sky. How did everything move? Nobody had done much work before them on this, so it wasn't surprising that they made some mistakes - but at least they had a go...

Aristotle

One of the greatest philosophers was Aristotle. He got to work on the flat Earth thus: he commented on the fact that ships disappear over the horizon, and come back! They do not fall off the world as some earlier people believed. The world must be curved. Other 'proof' was the heights that certain stars reached in the sky depending on your latitude on the Earth. Eclipses gave the game away too, for the shadow of the Earth on the Moon always appeared round - that can only happen if the Earth is a sphere.

So the Earth became ball shaped. What about the movements of everything we see in the sky? - the Sun, Moon, Stars (some of which moved themselves). These moving stars are, of course, the planets. The word 'planet' comes from the Greek word 'Planetos' meaning wanderer, for this is what they did amongst the fixed background stars.

The Earth was, of course, the centre of the Universe. The Greeks reasoned that 'we cannot feel the ground moving'. They were also perfectionists and believed circles and spheres to be perfection, so Aristotle claimed the Earth was surrounded by these heavenly objects all moving within these perfect spheres. They had it all sewn up.

Ptolemy

A later Greek, Ptolemy, constructed this Earth-centred model to account for all the movements you could see in the sky. It was a complicated array of wheels within wheels that did indeed allow you to calculate fairly well where the heavenly bodies would be for any particular date. It was jolly complicated, but it needed to be because it was wrong, and it needed so many movements to correct for this Earth-centred view. This is how it remained for about 1,500 years... During these years there was some astronomy done. The Arabs were refining observations of star positions, while giving them names. Indeed many of the star names we know today come from this time. The Renaissance of Astronomy started in Europe in the 1500's.

Copernicus

One man, a lawyer, priest, doctor and an astronomer, named Nicolas Copernicus, was one of the first to look closely at the Earth-centred Universe. And did his ideas cause a great deal of fuss and bother! For after careful study of the heavens, he was to challenge the very teachings of the church concerning the movement of the heavens - not a good thing to do.

Because Copernicus was a great thinker, and even though he was a priest, he wasn't simply prepared to accept traditional teachings that the Earth was at the centre of the Universe. This all came about when he looked into night sky to see the planets in the wrong place. They were wrong because calculations made at the time, the ones originally based on the system of Ptolemy, said they should be somewhere else. Something wasn't right in space-land.

Brainy Copernicus decided the calculations needed adjusting, they were far too complicated anyway. He worked out that if the Sun were placed at the centre of the Universe then things would be much happier all round. He tried his new method calculating the new positions of the planets. Unfortunately, they still weren't exactly where they should have been, but it was much better and he had a nice cup of tea to celebrate.

The reason they weren't in exactly the right place was because he still believed that the planets moved around the Sun in perfect circles, which of course they do not. However, he was on the right track, not that he was entirely happy about letting the world, well particularly the church, know about his 'naughty' views.

Why was all this so bad? Well, 400 years ago, when the church was very rich and powerful, you may well have been executed for disagreeing with traditional views of the Universe. Copernicus knew his revelations would cause an upset and so he didn't allow his book, On the Revolutions of Heavenly Bodies, to be published until the day he died in 1543.

Now scientists had something to get their teeth into, not that everyone agreed with the Copernican theory. Three years after Copernicus died a baby was born who was to become the last of the great pre-telescope observers. Tycho Brahe was his name. He continued to believe the Earth was at the centre of everything, but his precise observations led to a refining of the Greek view with an 'interesting' combination of movements: the Moon went around the Earth, while the planets moved around the Sun, but this also moved around us. So, Tycho was not going to upset anybody. However, his observations led a superb mathematician, Johannes Kepler, down the road that was to lead to scientific theory overcoming religious non-scientific teachings.

Kepler

Initially Kepler's Universe was built of geometric shapes forming the basis for the gaps between the planets. Later, using Tycho Brahe's observations, the true nature of the heavens became apparent. Those perfect circles made way for elliptical orbits, which allowed the positions and movements of every planet to be calculated with 'ease'. From the early 1600's Kepler published three famous 'laws' which continued to erode the religious view. Which Kepler's laws were being published one further gentleman in Italy was to cause further upsets to the church's view, and the last place you wanted to cause trouble was right in the heart of the church.

Galileo

Galileo Galilei was one of the first to use a telescope to seriously study the sky. What he saw was to change his beliefs in the heavens. Far from the Moon, Sun and planets being perfect spheres, they were rugged, marked and spotty!

The Moon showed Galileo mountains and craters, the Sun had dark spots that moved and changed shape, Jupiter was seen with tiny moons in orbit around it, and Venus showed phases that were just not possible with the Ptolemy Universe.

Now, Galileo was Italy's leading astronomy authority. What he saw convinced him of the Copernican system, which did not please the church. To them he was like a traitor in the backyard. Galileo published his observations Italian, not Latin, which made matters worse. This meant everyone could read it, not just the important people. His book said of his ideas, 'People who couldn't see this were stupid'. A bad move that eventually lead to house arrest, and this is where he lived out the rest of his days. But the cat was out of the bag and with everyone making telescopes and seeing for themselves what Galileo had seen science was beginning to show that religion could not wipe-out or ignore knowledge any longer.

© Anton Vamplew 2008