Yes, but we should be careful here.

Aristarchus had an incredible idea that was well ahead of its time, but he didn't reach the conclusion of heliocentrism based on careful calculations or observations. Quite the opposite; He fully supported the Ancient Greek model of epicycle orbits of the known planets, and like Copernicus many hundreds of years later, was attempting to map the epicycular orbits of the planets onto the perfect Platonic solids.

His reasoning that the Sun was at the centre of the Universe was the result of the same thought process that all Ancient Greek natural philosophers engaged in; What was the cosmic hierarchical order of the five basic elements (Earth, water, air, fire, and quintessence)?

All of them had concluded that quintessence was at the top of the hierarchy, and so it surrounded and permeated all things. It was the crystalline medium of the Cosmos in which the fixed stars were embedded.

The disagreements came from deciding the order from there. The Aristotelean School put Earth next, so the Earth was given the dominant position in the Cosmos. Thales of Miletus also placed the Earth at the centre, but that was because he believed the Earth was composed almost entirely of water, and water was the second in the hierarchy after quintessence. Aristarchus placed fire as the next below quintessence, and so he concluded the Sun was at the centre of the Cosmos.

We must understand that Ancient Greek natural philosophers largely did not conclude results through careful measurement or practical demonstration, but instead took existing models and modified them to fit their own personal biases and conclusions. The epicycle model of the Solar System was particularly useful in these regards because if the movement of the planets didn't match one's predetermined conclusions, one could merely posit that there were greater or fewer epicycular movements of the planets when they dipped below the horizon, the Ancient Greeks being unable to view their orbital paths from the Southern Hemisphere.

The reason you've learned about and remembered the times when the Ancient Greek natural philosophers did use careful measurements and practical demonstrations, like Archimedes weighing King Hieron's crown, or Eratosthenes measuring the circumference of the Earth, is because those discoveries were the exception to the rule.

ITT: people repeating incorrect pop-history.

Copernicus was a well-regarded astronomer in his time, a minor clergy member (a canon), published his book with Church permission and dedicated it to the Pope.

Galileo is a bit more complex: he was originally left to do whatever he bloody well liked with his theories, until he started trying to perform his own theology, which the Church wasn't cool with. The Pope interceded on his behalf, told him to just stick to the science, and in response Galileo wrote him into his book as "Simplicio", literally calling him a dumbass in public. Something he actually did for several other of his powerful political allies.

So basically, act like an arrogant dickwad with zero political common sense in the cutthroat world of 17th century Italian politics, and you might just get placed under house arrest for the rest of your life.

Burn the witch!

Dude was in the know

Reposting an old comment of mine about the Greeks and heliocentrism:

> They "figured it out" but couldn't prove it. The hypothesis had three main issues that weren't solved until scientific knowledge caught up with astronomy:

> 1) Parallax. If the Earth moves around the Sun, then the stars should appear to move back and forth every six months, the same way that a stationary object appears to move when you move your head side-to-side. In fact the stars do show this behavior, but because they're so far away, it's unnoticeable without a telescope. The ancient Greeks believed the stars to be relatively close to Earth, so the parallax should've been much more apparent. Accepting heliocentrism would've meant accepting that the universe was far larger than they thought - they weren't ready to accept that.

> 2) Inertia. The ancient Greeks did not believe that an object in motion will remain in motion. They believed in the concepts of natural motion and disturbed motion, which, among other ideas, posited that force was proportional to velocity. So if the Earth is moving, why do flying birds not slow down and get left behind?

> 3) How can the Earth move? Again, this comes down to the ancient idea of natural motion. In their system of natural philosophy, heavy objects naturally fall to the ground. A heavy object in motion slows down and stops. Earth is the heaviest thing there is - it is literally the element of heaviness. So how can it be in motion? What force is moving the Earth?

> For these reasons heliocentrism was abandoned for 1500 years. It wasn't sacrilegious or anything; it was just deemed to be an interesting hypothesis that didn't stand up to scrutiny.

This cannot be true! I am the centre of the universe, burn him..

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I first learned this from the Junior Woodchucks Guidebook.

Read title as "Samoa" at first

And he wasn't called a blasphemous heretic like Copernicus was?

He wasn't the first to propose a Heliocentric model. Indian astronomers did that in the 8th and 9th Centuries BC.

BC

If the truths about the solar system that this guy discovered in the third century BC had been recorded & maintained and taught throughout the centuries, mankind would have been a lot further ahead in our understanding of our place in the universe.

But instead some religion decided to start teaching everyone that the Earth was the center of the universe and it took centuries for scientists & religions to straighten all that out again.