However, some experts note the same illusory phenomenon happens to the sun as well as constellations. (Plait, 2008) (Simanek, 2002)
The "experts" hail from astronomy and astrophysics, geometry and mathematics, philosophy and psychology, physics and light-wave science (as in electromagnetic spectrum visible light), and, of course, NASA (the National Aeronautic Space Administration). Some who try to explain the Illusion say and have said they're not experts as much as they are admirers of moonrises and moonlit nights. They noticed the Illusion phenomenon and thoughtfully pondered it. They've invested time and energy toward solving the mystery. So, in some explanations trying to account for the Moon Illusion, besides intellectual calculations, often there are emotional components, akin to "Beauty is in the eyes of the beholder."
Explanations are centuries old as well as comparatively new. They run the gamut in-between. Champions of various ideas don't usually have adversarial confrontations. Rather, ongoing dialogs center around this theory compared to that theory. Some theories proffer physical rationale and/or geometry. Others theories propose, "It's all in your head!"
The website named "Sandlot Science" asserts that about 85% of people are able to see the Illusion. The interesting questions are, "What about the other 15% Why don't they see it" Some mathematics-based explanations purport that the moon is always the same size. Thus, the 15% merely see reality. The other 85% are playing tricks on themselves. Nonetheless, for anyone in the 15% who has not seen the Illusion and is curious to see what 85% of their fellow Earthlings see, this link to SandlotScience.com has an interactive graphic display showing the Illusion phenomenon. http://www.sandlotscience.com/Moonillusion/Moon_Illusion_Demo.htm
The moon's size may be exaggerated somewhat in Sandlot's simulation. Near the horizon it is 150% of the size that it is high in the sky (the top right corner of the simulation). Then again, maybe 150% is not stretched quite as much as a fish story about the size of one that got away. During some nights, people report seeing the moon bigger on the horizon than on other nights. Why is that Science-minded people notice that this is often true about summer nights.
Here is one physical theory. Air is hotter in summer. Heat radiates from Earth's surface after sunset. It permeates upward. In the summer this happens on roads, in deserts and elsewhere depending on how cooked a surface gets from the sun beating down on it. To the human eye it looks like shimmering heat waves rippling upward from the baked surface. The shimmer and ripple effect is distortion caused by heat. Heat wave distortion rippling around the image of hot objects makes them look larger than on normal days when heat waves aren't visible. Air is a fluid. Light refracts in fluid. Heat coursing in a fluid can distort appearances of objects seen through the fluid. Because of the rippling nature of the heat waves, an object's appearance ripples a little bit to the left, a little bit to the right, a little bit up, and a bit downward. Ergo, visibly the object's image enlarges perceptibly in all directions. The image shimmers