Emeritus professor Don McCready debates moon illusion on BBC
Released: November 21, 2006
Have you ever noticed that the moon seems larger in size when it is near the horizon than when it is high in the sky? Some people judge it to be as much as twice as large, but the average estimate is 50 - 75 percent larger. The so-called "moon illusion" has perplexed people since earliest historical times.
University of Wisconsin-Whitewater Emeritus Pyschology Professor Don McCready has spent a great deal of time studying this phenomenon. McCready was recently approached by the British Broadcasting Company (BBC) to be involved in their weekly radio program, "More or Less."
McCready offers a nontraditional explanation of the moon illusion first presented in 1983 and has since been defending his view on the topic. He believes that there is a difference between perceived linear size and perceived angular size of the moon. This makes the horizon moon have a larger perceived angular size than the moon at its highest point. He debated this viewpoint with the New York University Emeritus Psychology Professor Lloyd Kaufman and Helen Ross, author of the book, "The Mystery of The Moon Illusion."
"The new theory on the moon illusion is gradually getting more support," McCready explained. "The standard viewpoint taught in schools and found in textbooks uses one word for the perceived size of the moon when in actuality angular size and linear size are two different things."
Since retiring from UW-Whitewater in 1992, McCready has spent much of his time researching the new viewpoint of the moon illusion. In 1999, he constructed his own Web site dedicated to his research. He kept the site updated until 2004 when he decided to end his research on the moon and became a full-time artist. Painting has been a passion for McCready and his wife for years and now he can allow more time for his craft.
Nearing the age of 80, McCready cannot live without his computer. He has formed two Web sites: one dedicated to moon illusion research and one that displays his artwork.
To get more information on McCready's moon illusion viewpoint, visit http://facstaff.uww.edu/mccreadd. To view his and his wife's professional quality portraits and landscapes, visit http://www.mccreadyart.com.- Mike Varga,vargama04@uww.edu
