Nicolaus Copernicus · Science

The Loops in the Sky

For centuries the planets’ baffling backward loops forced astronomers to bolt circle upon circle onto their models. Copernicus dissolved the mystery with a single insight: the loops are an illusion created by our own moving Earth.

What you'll be able to recall

You learned that the planets’ retrograde loops, which the old system explained with epicycles, fall out naturally from a moving Earth overtaking the slower outer planets - and that heliocentrism also fixes the true order and distances of the planets. In your own words, explain how a moving Earth turns retrograde motio…

Leads to Galileo Galilei.

epoché — a humanities education that remembers you.