“The Earth orbits the sun in a perfect circle.”

For centuries, the idea that celestial bodies, including Earth, journey around the sun in perfect circles was a deeply held belief. This misconception stemmed from ancient Greek philosophy, notably advanced by thinkers like Aristotle, who posited that the heavens were a realm of divine perfection, and therefore, only the most perfect geometric shape—the circle—could govern the movement of planets. This conviction was so strong that even Nicolaus Copernicus, who revolutionized astronomy (Deals) by placing the sun at the center of our solar system, still clung to the notion of circular planetary orbits.

The scientific understanding of planetary motion took a monumental leap in the early 17th century thanks to Johannes Kepler. Working with the incredibly precise astronomical observations meticulously collected by his mentor, Tycho Brahe, Kepler spent years trying to reconcile the data, particularly for Mars, with circular paths. He discovered that the observed movements simply did not fit. His brilliant insight, which shattered nearly two millennia of astronomical orthodoxy, was that planets actually travel in elongated, oval-shaped paths called ellipses, with the sun situated at one of the two focal points of that ellipse. This groundbreaking discovery became Kepler's First Law of Planetary Motion.

Despite this scientific evidence, the myth of a perfectly circular orbit persists for a few reasons. Visually, when depicted in many simplified diagrams, the Earth's orbit around the sun *appears* almost perfectly circular because its eccentricity—the measure of how much an orbit deviates from a perfect circle—is very small, about 0.017. If Earth's orbit were drawn to scale, it would be indistinguishable from a perfect circle to the naked eye. Furthermore, a perfect circle is a special case of an ellipse, and in the dynamic environment of space, even the slightest gravitational tug from other celestial bodies would nudge a perfectly circular orbit into a slightly elliptical one over time.