r/Solar_System

credit - soph_astro

The sun isn’t always the exact center of our solar system. ☀️

In this Space Oddity, Erika Hamden explains what the barycenter of the solar system is, and how it may not always be inside of the Sun itself. The variations in the barycenter can be explained by the large masses of the outer giant planets!

*Orb: On the Movements of the Earth* is a Japanese animated series centered on the proof of the heliocentric theory.

While it does not strictly adhere to historical facts, the characters are portrayed with a compelling sense of realism.

In the series, there is a scene featuring Count Piast, an elderly astronomer who has dedicated his life to proving the geocentric theory. He catches a glimpse of Venus in a "full" phase—an impossibility under the geocentric model—and, desperate to refute that memory, asks Ogzy, a young man with exceptional eyesight, to conduct an observation.

Count Piast had seen Venus fully illuminated just once. Despite his desire to deny it, he could not resist the urge to verify the truth.

The scene where Ogzy observes Venus in this full phase leaves a powerful impression.

However, I did not fully grasp why a fully illuminated Venus would disprove the geocentric theory.

I recently found the following simulation sites demonstrating how Venus appears, which helped me understand the concept.

●UNIVERSITY of NEBRASKA–LINCOLN

Venus's movement and appearance based on the geocentric theory

https://astro.unl.edu/classaction/animations/renaissance/ptolemaic.html

Venus's movement and appearance based on the heliocentric theory

https://astro.unl.edu/classaction/animations/renaissance/venusphases.html

Intrigued by the phases of Venus, I created a tool to observe them.

It is based on an astronomical clock app that utilizes the *Wadokei* (traditional Japanese clock) system—a timekeeping method rooted in the sun's movement.

It uses Apple Watch complications to display the times when Venus is visible, as well as its size and current phase.

Wadokei57 Astronomical clock

https://apps.apple.com/us/app/wadokei57-astronomical-clock/id6748839654

In addition to showing Venus's phases, apparent size, and rise/set times, the app features a diagrammatic view displaying the relative positions and distances of the Sun, Venus, and Earth.

An update including the Venus complication is currently under review, and I expect it to be released soon.