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.

Eat Your Carrots! The Chemistry of Vision

 

18th-century hand-colored etching of woman pushing wheelbarrow full of carrots.

“Sandwich Carrots-Dainty Sandwich Carrots.” Hand-colored etching. Gillray, James, 1756-1815, engraver. Published by H. Humphrey, 1796 Dec 3d, London.
Image courtesy of Library of Congress.

You’ve probably heard the old adage about eating carrots for good vision. Well, there is some truth to it. Carrots contain a high concentration of β-carotene which gets broken down in the intestines to form the aldehyde (hydrocarbon) form of vitamin A, cis-retinal. Vision deteriorates in the absence of vitamin A because cis-retinal is trafficked along the protein, opsin, to produce electrochemical signals from light.

Our retinas perceive light in tiny particles called photons. As soon as these photons hit the retina, they isomerize cis-retinal to trans-retinal.  Trans-retinal then bonds to opsin to form rhodopsin. Rhodopsin is a purple pigment in the photoreceptor cells of the retina that reads blue-green light. This is the first step of the phototransduction cycle where photon energy is transferred to a series of signaling and diffusing protein complexes.

Retinal isomerism drawn with ChemDraw

Mutated forms of rhodopsin will be folded and transported differently and could lead to deteriorated vision or blindness. In more rare cases, mutations can cause rhodopsin to be constantly activated, even in the absence of light. Hypersensitivity, autoimmune disorders, and mutations can all cause rod cells in the retina to undergo apoptosis or cellular self-destruction. This sort of degradation of the retina will ultimately lead to deteriorated vision and eventually blindness.

The absorbance of cis-retinal is optimized at approximately 100 nanometers less than rhodopsin and it is a very rigid molecule because of the arrangement of its double bonds. Thanks to isomerism, we can see in color as opposed to ultraviolet! As all of the above demonstrates, our ability to see involves a series of complicated and precisely regulated bio-chemical processes, and carrots play their role.

We will be exploring more about vision loss and blindness in the upcoming GLIMPSE issue 10, Blindness. In the meantime, let us know your thoughts, research, questions, or experiences related to the topic.

If you’re interested in the chemistry of vision and why we perceive the section of the electromagnetic spectrum that we do, you might also be interested in GLIMPSE, issue 4, Color, and the article on “Human Potential for Tetrachromacy” by Kimberley A. Jameson and the online supplementary article.

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Myya McGregory is the GLIMPSE 2012 Science Writing Intern. She is a junior double-majoring in chemistry and economics at Williams College. She enjoys music, dance, and literature.

Study Imaging Science at MIT for $0 a day

Digital refocusing is a computational photography technique that allows one to change the focus point in an image after capture, using additional data collected through camera enhancements such as a coded aperture mask. (Image by Prof. Ramesh Raskar.)

September’s here, and it’s time to put the thinking cap back on. No need to enroll or pay tuition…or to do homework. Official students, garage tinkerers, lifelong learners, and the generally curious can learn about the latest in imaging technology from the MIT Professor Ramesh Raskar. Now available via MIT’s (visionary) Open Courseware site:

“Computational Camera and Photography” http://ocw.mit.edu/courses/media-arts-and-sciences/mas-531-computational-camera-and-photography-fall-2009

Thanks, Massachusetts Institute of Technology and Professor Raskar, for sharing your knowledge with everyone that’s interested!

Check out more DIY MIT courses here:

http://ocw.mit.edu/courses/

Hmmmm… imaging technology not your thing?

How about:

“Film as Visual and Literary Mythmaking?”

Or

“Laboratory in Visual Cognition?”

Or….

Mama Don’t Take My Polaroid Away

Much like the American singer/songwriter Paul Simon who crooned nostalgic over visual technology in his 1970s hit “Kodachrome,” Austrian entrepreneur Florian Kaps is making his own case for keeping the Polaroid camera alive in today’s visual market.

Wall Street Journal writer Eric Felten in “It’s Baaaaack! But Polaroid Film Was Just Lucky” describes Kaps’ tenacious journey to save the Polaroid from utter oblivion—from begging the junk men not to destroy the last functioning Polaroid factory machines outside of Amsterdam while he vigorously raised money to save them, to putting together a team of scientists to come up with a new sepia-toned black-and-white film that could be used in standard Polaroid cameras (the arcane chemicals originally used to run in the machines could no longer be produced).

What’s resulted from Kaps’ valiant efforts to preserve a medium that we often associate with the psychedelic, saturated ’60s (although it was invented in 1929) is The Impossible Project. It’s a website that allows individuals around the world to peruse and purchase classic Polaroid cameras with modern twists, and also a wide variety of analog instant film.

The Glimpse team gives kudos to Kaps for preserving a nearly extinct perspective, and for keeping the dialogue between new and old visual technology alive and well.

Above image titled “Enschede5.” ©The Impossible Project

Finding the stars through the light pollution

Courtesy of C. Mayhew & R. Simmon (NASA/GSFC), NOAA/ NGDC, DMSP Digital Archive

It’s a breathtaking sight, looking down at a glowing Earth. An ominous one, too.

For those of us living inside the glow who can only look upward, the brilliant stars are becoming less so.  They’re fading behind streetlights and porchlights and lamplights and headlights. And in Glimpse‘s forthcoming Cosmos issue, Scott Kardel wants them back.

Kardel spends his days (and starry nights) at Palomar Observatory, where astronomers dodge terrestrial lights to capture cosmic ones.  Stay tuned for “Dimming the Lights” in March 2010 for reasons why not to be scared of the dark.

(The Cosmos issue  scheduled for blastoff! in 5..4…3…)

From Our Internal Organs to the Cosmos

Congratulations to this year’s Nobel prize in physics recipients!

Congratulations to this year’s Nobel prize in physics recipients!

On Tuesday Oct. 6, 2009 at 11:45 am, the recipients of the 2009 Nobel Prize in Physics were announced at The Royal Swedish Academy of Sciences in Stockholm. One half of the prize was awarded to Charles K. Kao for his research in glass fiber optics, and the other half of the prize was evenly divided between Willard S. Boyle and George E. Smith for their invention of the charge-coupled device, or CCD.
In 1966 with his college George A. Hockham at Standard Telecommunication Laboratories, Kao proposed a solution for the then thought implausible transmission of long range information technology. They suggested that impure glass particles inhibited long range light transmissions in optical fibers. By chemically purifying the glass with fused quartz and fused silica, Kao purposed a method of extracting an ultra-thin fiber thread that would carry at least 1% of light over the distance of 1 kilometer. Today this glass fiber optics technology is fused with our everyday lives and employed in various forms (like the internet), allowing for instantaneous transnational and global cable communication. 
In 1969, Willard S. Boyle and George E. Smith of Bell Laboratories were drafting a proposal for an electronic information storage device. What they discovered instead was a light transmission technology, a digital image sensor, based on Albert Einstein’s theory of the photoelectric effect. When particles of light enter the light sensitive silicone plates, the CCD, electrons in the photocells emit at equal proportions as the incoming light, transferring the incoming optical image into a digital one in the form of pixels; opening the door for even more novel inventions like pixelated digicams, 96 megapixel images of outer planets on the Hubble telescope, and internet porn. The image above shows the CCD faceplates of the primary digital imaging telescope at Salon Digital Sky Survey.
For more information about the 2009 Nobel laureates visit the Nobel prize website.

On Tuesday Oct. 6, 2009 at 11:45 am, the recipients of the 2009 Nobel Prize in Physics were announced at The Royal Swedish Academy of Sciences in Stockholm. One half of the prize was awarded to Charles K. Kao for his research in glass fiber optics, and the other half of the prize was evenly divided between Willard S. Boyle and George E. Smith for their invention of the charge-coupled device, or CCD.

In 1966 with his college George A. Hockham at Standard Telecommunication Laboratories, Kao proposed a solution for the then thought implausible transmission of long range information technology. They suggested that impure glass particles inhibited long range light transmissions in optical fibers.  By chemically purifying the glass with fused quartz and fused silica, Kao purposed a method of extracting an ultra-thin fiber thread that would carry at least 1% of light over the distance of 1 kilometer. Today this glass fiber optics technology is fused with our everyday lives and employed in various forms (like the internet), allowing for instantaneous transnational and global cable communication. 

In 1969, Willard S. Boyle and George E. Smith of Bell Laboratories discovered the CCD while drafting the proposal for a technological information storage device. What they came up with instead was a light transmission technology, a digital image sensor, based on Albert Einstein’s theory of the photoelectric effect. When particles of light enter the light sensitive silicone plates, the CCD, electrons in the photocells emit at equal proportions as the incoming light, transferring the incoming optical image into a digital one in the form of pixels; opening the door for even more novel inventions like pixelated digicams, 96 megapixel images of outer planets on the Hubble telescope, and internet porn. The image above is of a star formation called the Orion Nebula. It was taken by the Advanced Camera for Surveys (ACS) on NASA’s Hubble Space Telescope in 2006.

For more information about the 2009 Nobel laureates visit the Nobel prize website.