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.

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Experience Sunset: James Turrell’s Skyspace at the Ringling Museum of Art

Imagine staring into a deep dark blue pool of calm water and getting lost in its depth.

Now imagine lying on your back on a floor of a museum and the ‘pool’ is the sky seen through a deftly designed 24-foot square ‘hole’ in the ceiling. Enter Skyspace and experience Joseph’s Coat by James Turrell at the Ringling Museum of Art in Sarasota, Florida.

Color photograph

James Turrell. Joseph’s Coat, 2011 © James Turrell, Photo by Giovanni Lunardi.

Turrell’s kinesthetic art is an invitation to experience energy in relation to light, sound, wind, and the canvas of a changing sky by quieting the mind and observing. Opening our senses and our consciousness to the world around and within us, while lying on a bench or the floor to experience the sky, allows and even encourages a transformation of one’s perception.

The brochure given at entry to the sunset experience states; “James Turrell wants you to be aware of your active participation in perception – and see yourself seeing.”

Entering the courtyard of Joseph’s Coat, a gallery lined with long wooden benches felt to me like any other indoor courtyard until I looked up. The ceiling thinned at the opening to the sky. If inverted it could be a sheer dropoff without ledge or dimension. The floor was a slightly inclined square with a perimeter of drains to carry rain away and which double as light tubes for the sunset show.

I placed my mat on the floor between benches and noticed the small-leafed vines that climbed the plaster walls forming elegant green pathways upward. The scent of jasmine vines wrapped around a pillar nearby enlivened the air and brought greenery to the sparse courtyard.

Turrell’s Skyspace draws us in just by looking up, and I found that it offered me a chance to pause, to listen, to feel and yes, to see. The experiential nature of his work including lying on one’s back and watching the sky change, especially brilliant at sunset, is a dance between an artist’s work and the viewer’s evocative experience: the powerful essence of art. There for an hour, relaxing on my mat, hearing my breath, I tried not to fidget. I became mesmerized watching the grey clouds pass over following a strong summer storm. A train whistle in the distance caught my attention, like a Tibetan gong just before meditation.

The post storm breezes moved the clouds quickly and constantly changed the sky as if lifting layer upon layer of veils to reveal finally, a blue sky. A bird, then another, darted through the air on a strong gust followed by a jet’s contrail that curiously, as if on tiptoe, entered the square and moved diagonally from upper right to lower left, thinly sketched as if with a fine-tipped brush, then slowly dissolved by the wind into a series of thick wavy lines. Soon the remaining thick grey clouds thinned to wisps, faded to lighter pink, then to salmon and coral and with the help of the LED lights subtly projected up from the floor and elsewhere I couldn’t discern, the walls changed color too.

Deep ocean – blue sky set in and from the deepest part of the pool, a star, then another glimmered at the edge of the ethereal canvas. Cream to green to red walls and deep dark sky descending. We were entering the night. Or, maybe the night was entering the dozen viewers on the floor and benches of the Skyspace.

“How is it,” I thought to myself, “That this dance is ongoing every millisecond of our lives, at night quietly swirling above us and around us as we work, love, play and sleep? Yet, we are not aware of it.”

The movement and realization of energy, of dynamic molecules, and the give and take of this seemingly innocuous hole to the sky gave me a chance to pause, to listen, to feel and breathe, and yes, to see.

Molecules and light beams, daylight and darkness, starlight and Self and Other. To stare into a pool of space within the dynamic nature of changing light, makes life art and all that is, the world beyond and within us, Art. Clearly, it is a glimpse of the ongoing creative process. I’m a relative newcomer to the art of Mr.Turrell but through my discovery, I am drawn back… or should I say, drawn in again and again.


One can experience Joseph’s Coat Skyspace every day that the Ringling Museum of Art is open and two nights each week for sunset viewing. Yoga mats are encouraged. Check with the museum for specific schedules and details.


By Pamela Erickson, GLIMPSE journal correspondent. Erickson is an author, artist and librarian who lives on the Florida Gulf Coast with her husband and pets. Having taught for over 30 years, she seeks writing as a form of reflection, exploration, conversation and solace. Her novel, Each Other, is available here.

Suomi Perspective-Check: Hi-Def View of Our Little Earth

Hi-Definition Composite Satellite Photograph of Earth, January 2012

Hi-Definition Composite Satellite Photograph of Earth, January 2012. Image Credit: NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring

(via NASA.gov, 1/25/2012)  “A ‘Blue Marble’ image of the Earth taken from the VIIRS instrument aboard NASA’s most recently launched Earth-observing satellite – Suomi NPP. This composite image uses a number of swaths of the Earth’s surface taken on January 4, 2012. The NPP satellite was renamed ‘Suomi NPP’ on January 24, 2012 to honor the late Verner E. Suomi of the University of Wisconsin.

Suomi NPP is NASA’s next Earth-observing research satellite. It is the first of a new generation of satellites that will observe many facets of our changing Earth. Suomi NPP is carrying five instruments on board. The biggest and most important instrument is The Visible/Infrared Imager Radiometer Suite or VIIRS.”

Is There Life on Gliese 581d?

Image courtesy of NASAblueshift

Forget men on mars; exoplanet Gliese 581d in the solar system neighboring ours may have conditions just right for supporting some forms of life. While the name doesn’t exactly roll off the tongue, French researchers made a pretty fascinating discovery about the planet. For a few years scientists have thought the planets orbiting the star Gliese 581 could support life, but until recently it was believed Gliese 581d was too cold. However, when the researchers simulated the atmospheric make-up of the planet, they found it rich in carbon dioxide, creating a warm enough climate to possibly support oceans and rainfall.

Though don’t get too excited (we’re looking at you, Lance Bass). The incredibly dense air on Gliese 581d makes for a red, murky atmosphere toxic to humans. It would also take roughly 300,000 years to reach the planet on a spacecraft. Visiting it may be out of the question for now, but it’s exciting and just a little scary to think about the vast and varying environments where life can exist.

The Ever More Accessible Space Oddity

Image courtesy of flickr.com member Tim Fields

While the never-ending slew of new technology that bombards us everyday can sometimes feel overwhelming, complicated, and unnecessary, every so often a product comes along that we at GLIMPSE simply love. Take for example, the SkyProdigy, a point-and-shoot telescope.

SkyProdigy is for people who would love to gaze at the stars but are hesitant to even touch a telescope for fear of breaking something very expensive. You just have to point it towards the sky, push a button, and voila! An incredible view of the moon or the North Star is at your fingertips.

While SkyProdigy doesn’t come out until July, it’s great that astronomy is being made more accessible. Citizen astronomers will love that they can now capture the stunning views their telescopes provide on their iPhones thanks to the ingenuity of the Magnilux Adapter. It seems it’s never been easier to add ‘amateur astronomer’ to your title.


Supernova Girl

Image courtesy of NASA, ESA, (STScI/AURA) and J. Green

Do you remember what you were doing when you were ten years old? Perhaps working through the complexities of long division or playing kickball at recess. Whatever kept you occupied, we think it’s safe to say you were not discovering a supernova, an intensely energetic explosion that occurs at the end of a star’s lifetime. Unless of course, you happen to be Kathryn Gray. Ten-year-old Gray is the youngest person to make such a discovery. With her father, an amateur astronomer, at her side she spotted the supernova 240 million light years away on New Year’s Eve. To find what NASA has deemed to be “one of the most energetic explosive events known,” astronomers use a computer program that compares different nighttime images of the sky taken from the same location. If there are any changes, there’s a good chance it’s a supernova. Most fully-grown astronomers search for thousands of hours before they discover the star. For Gray, it took fifteen minutes.

It’s quite impressive, awesome, and heartwarming to find such a young person interested in the sciences (and making history along the way). We at GLIMPSE are thrilled to see appreciators—at any age—of the art + science of seeing.

Allison Nonko

Mostly Sunny

Photo courtesy of NASA Goddard Space Flight Center

If you’re not a fan of the sub-zero temperatures the upcoming season bestows upon us, perhaps reading this NASA report about a giant eruption on the sun will warm you up. In August, an entire hemisphere of the sun exploded—NASA’s Solar Dynamics Observatory along with the STEREO spacecraft recorded the eruption in unbelievable detail. So what does it all mean? Well before this eruption, explosions on the sun’s surface were believed to be isolated incidents, independent of one another. But now scientists think all solar activity is interconnected. One solar physicist came to this staggering conclusion: “To predict eruptions…we have to know the surface magnetic field of practically the entire sun.” The surface area of the entire sun? Oh, about 2.3 trillion square miles. And the magnetic field is unbelievably complex, varies in strength across the sun’s surface, and extends far out into space. We have a feeling the collected thought bubble over all solar physicists’ heads right now reads ‘oy.’

Allison Nonko