Markus Schwarz wrote:
The problem for the Greeks was that they had few means to test their hypotheses. And since they couldn't back up their hypotheses with (much) observational evidence, and since the most influential thinkers of their day believed in a geocentric universe created and ruled by gods, the world views of these pioneers were forgotten for many centuries.
I am no historian, but from what I have read the observational evidence at the time of the ancient Greeks did favour a geocentric model (see second paragraph of the Wikipedia article
Also, the modern view is that the debate, whether geocentrism or heliocentrism is correct, is now obsolete. Both coordinate systems can be used to describe the motion of the planets; it just so happens that the coordinate system where the Sun is at the center allows for a relatively easy description of planetary motion. My colleagues were to surprised to learn that but this is indeed what general relativity tells us (see here
Certainly neither the geocentric or the heliocentric model is correct. The Sun is not at the exact center of the solar system, and the solar system is definitely not at the center of the universe! (The center of the universe, coincidentally - as Chris has pointed out - is more likely the exact moment of the Big Bang, since everything has been flowing out of that.)
But I think it can definitely be argued that as far as the solar system is concerned, the heliocentric model is a far better description of it than the geocentric one. Certainly that is true if we consider the motion of all the planets in the solar system. (I'm not saying that a geocentric world view can't be mathematically constructed, but doing such a thing seems pointless to me. After all, we know that planets are born out of the protoplanetary disks that surround newborn stars - so how reasonable is it to say that the star is orbiting the disk, rather than the other way round?)
So the reason why Aristarchos and the others didn't win out is that they didn't have enough political clout. Those who preferred the heliocentric universe, made and ruled by gods, were simply stronger and therefore had their way.
Why did the heliocentric model win in Renaissance Europe? I'm just speculating, obviously, but I think it has to do with the fact that Isaac Newton first and foremost was a mathematician, and early 17th century England - poised on the threshold of ever greater power, and eventually on world domination - probably realized the value of a superb mathematician, whose mathematical formulas could solve so many mechanical and engineering problems for them, thus making them ever more invincible.
The heliocentric model had already gained credibility, thanks to Johannes Kepler (and Tycho Brahe). Using Brahe's superb observations of the solar system, Kepler was able to mathematically prove that the planets follow elliptical orbits. The world likely didn't change much right away due to Kepler's breakthrough, but Newton could apply his celestial mechanics to show why
planets follow elliptical paths. Besides, Newton's cosmology was also acceptable from a religious point of view. Rather than dethroning God, Newton turned the deity into the omnipotent clockmaker of the universe. In England, those in power probably liked the idea of a god that had given them a lot of leeway by constructing the clock-universe and winding it up, but had then opted to stay in the background to allow enterprising and clever people (like themselves) to explore and conquer their world.
Moral: You don't necessarily win because you are right, but because powerful people like your ideas.