Moon Illusion - Science News F rom Science News, Vol. Assumes New Sizes People have long noted that a full moon seems to shrink and expand in size depending on its heavenly position. A moon looks larger near the horizon than perched high in the sky, although its distance from Earth remains the same.
Scientists have yet to unravel the so-called moon illusion.
Experiments now indicate that a horizon moon grows larger because it lies near visual markers of depth and distance on Earth s landscape that make it look much farther away than a higher moon. Psychologist Lloyd Kaufman of Long Island University in Brookville, N.Y., and his son, physicist James H. Kaufman of the IBM Almaden Research Center in San Jose, Calif., conducted the new research. Since 1960, he has championed a theory that the brain automatically estimates distances to objects and then interprets their size accordingly. Similarly, he argues, visual cues on the terrain leading to a horizon moon indicate that it lies at a vast distance from the observer. This distance estimation inflates its perceived size.