# Aristarchus Homeschool Lesson

In this Aristarchus Homeschool Lesson, you will learn about Aristotle’s geocentric model of the universe and why Aristarchus did not think it was correct. Aristarchus was a scientist ahead of his time. His heliocentric theory, that the earth was not the centre of the universe, and that rather the earth orbited the sun, would not be accepted as truth for many years.

### Aristarchus Homeschool Lesson:

#### Resources

This was yesterday’s lesson from Dr Wile’s excellent curriculum, Scientists of the Ancient World. We started this book a while back, and then stopped when Charlotte’s health got bad. I’m tentatively picking it up again during our morning meeting.

#### Biography

Aristarchus (310-230 BC) is a lesser well known astronomer, Ancient Greek scientist and mathematician. From Ionia, he was a student of Strato of Lampsacus, the bulk of whose education was at Alexandria. Known as Aristarchus of Samos, he postulated the revolutionary theory of a heliocentric solar system. This went against the highly thought of Aristotle, who believed our solar system to be geocentric. He also believed that the stars in our universe were in fact far away stars, influenced by Anaxagoras who went before him. However, he had no means to prove his hypothesis, as telescopes were not as powerful as they are now.

#### Heliocentric verses Geocentric

Aristotle was absolute in his belief that the earth was the centre of the universe. His geocentric model showed the earth at the centre whilst the sun and planets rotated around it. Ptolemy back him up in this assertion:

Aristarchus refuted this. Measuring the sun and moon in comparison to the earth (incorrectly, as it turned out), he hypothesised that the earth, and the rest of the planets, orbited the sun. On realising the comparative size of the sun, he concluded that the much smaller earth was far more likely to orbit the sun, rather than the huge sun orbiting a small earth.