Galileo’s illusion solved by New York vision researchers

Portrait of Galileo Galilei, 1605-1607, by Domenico Tintoretto. Image courtesy of Wikimedia Foundation.

Portrait of Galileo Galilei, 1605-1607, by Domenico Tintoretto. Image courtesy of Wikimedia Foundation.

It was 1632, and the father of modern astronomy was perplexed as to why Venus, when observed by “naked” eye, would appear substantially larger than Jupiter, which was actually four times larger than Venus. He knew that Venus’ exaggerated size must have something to do with it’s halo, or “radiant crown” as he described it, and that this halo must have something to do with his eyes, and not the celestial objects themselves. Observations via telescope presented a more accurate visual representation of the mathematically-verifiable proportions of the planets.

Almost 400 years later, Neuroscientists Susana Martinez-Conde and Stephen L. Macknik, eloquently explain the January 2014 published findings of the State University of New York’s vision researchers Jens Kremkow, Jose Manuel Alonso and Qasim Zaidi:

By examining the responses of neurons in the visual system of the brain—to both light stimuli and dark stimuli—the neuroscientists discovered that, whereas dark stimuli result in a faithful neural response that accurately represents their size, light stimuli on the contrary result in non-linear and exaggerated responses that make the stimulus look larger. So white spots on a black background look bigger than same-sized black spots on white background, and Galileo’s glowing moons are not really as big as they might appear to the unaided eye.

These now-isolated differences in how our photoreceptors operate also explain why it is easier to read black text on a white page, than to read white text on a black page, a topic of interest to our typographer and font designer friends.

Do you love Galileo as much as we do? Check out the GLIMPSE Cosmos issue, available in our archives.


GLIMPSE journal is an interdisciplinary supercollider of works that examine the functions, processes, and effects of vision and its implications for being, knowing, and constructing our world(s). Each theme-focused issue features articles, visual essays, interviews, and reviews spanning the physical sciences, social sciences, arts and humanities. GLIMPSE contributors are leading and emerging scholars, researchers, scientists and artists from around the world. Some of our contributors are independent thinkers and doers with no formal institutional affiliations, and others are affiliated with the most respected research institutions in the world. Read all about them.

We ♥ Typography

Image courtesy of flickr.com member Brenda Starr

For those who like to see the procedure behind the product (How It’s Made, anyone?), you just might love this essay. Type designer (and GLIMPSE Helvetica film discussion panelist) David Jonathan Ross wrote about his thought-process behind a few typefaces he created. Ross explores the impact and importance of each letter’s relationship with thick and thin strokes, writing with a passion that makes it truly enjoyable to read.

For me, the relationship of thicks and thins is more abstract. While stroke and gesture are interesting subjects, what fascinates me is how any thick/thin relationship can define the vocabulary of shapes in a typeface, and how those shapes can in turn produce unexpected textures and rhythms of black and white. This fascination has served as the jumping off point for three of my typefaces, each one approaching stress and contrast in a different way.

Ross’s essay is featured on the blog “I Love Typography.” You can read the rest of his piece here.

Allison Nonko