That's interesting about the "giant star" hypothesis. I never knew that, and it makes sense based on what Kepler knew at the time. Today, we know that the appa

That's interesting about the "giant star" hypothesis. I never knew that, and it makes sense based on what Kepler knew at the time. Today, we know that the apparent size of stars is an illusion due to diffraction. In principle, even if stars actually were infinitesimal points of light, they would still appear as disks in optical instruments. Smaller apertures (like our eyes) make the disks larger. Only in recent decades with special techniques can we resolve the actual apparent size of a star.