Interactive sky-geometry demo explains why a nearly full Moon can appear to point upward after sunset

A blogger explores the lunar terminator paradox, where the Moon’s illuminated side can appear to point upward even after the Sun has set. Using a custom visualization, he shows the effect comes from viewing the Moon from below as it rises, revealing more of the shadowed lower edge.

The post highlights how intuitive flat-sky reasoning often fails for celestial geometry, especially when observers ignore perspective on the spherical sky. Simple interactive models can make astronomy concepts more accessible by turning a puzzling optical illusion into a clear viewpoint effect.