The Illusion of Color in Astrophysics


Study on Colors in Astrophysics – Ongoing Research

Under specific atmospheric conditions and with the technological tools employed, stars or planets may appear to emit green or blue light to some observers. However, as illustrated in the accompanying diagram, this is often nothing more than an optical illusion. The blue region seen in the diagram is actually a medium gray, entirely desaturated. You can verify this by using Photoshop’s color picker tool (or an analogous method) to check the true color values.

This phenomenon raises interesting questions about how color perception in astrophysics can be influenced by both atmospheric effects and the limitations of observational tools. How much of what we “see” in the cosmos is truly the color of the objects themselves, and how much is a product of the interaction between light, our atmosphere, and the instruments we use to detect it?

The Architecture of Light

Colors, though fundamentally phenomena of light, are not merely superficial aspects of perception. They play a structural role in organizing visual elements. For example, applying contrasting colors to a series of repetitive graphic patterns—while varying their distribution—can dramatically alter how they are perceived. This demonstrates how color is not just an embellishment but an active force in shaping visual reality.


As Goethe put it, “Colors are the deeds and sufferings of light.” More than a sensory experience, they influence our perception of space, depth, and meaning, revealing the intricate dialogue between vision and cognition.

🔍 Explore more about the illusion of colors.

Reflections of the Self

The mirror stage, conceptualized by Lacan, occurs in humans between six and eighteen months of age. It is the moment when a child perceives a unified image of their body and recognizes themselves in the mirror—a process rooted in the imaginary dimension—often accompanied by a sense of jubilation. This stage marks the emergence of narcissistic identification with the self.

But what about animals? Do they recognize themselves as a tangible entity in a mirror, or does their reflection remain an enigma to them? Research suggests that self-recognition in a mirror is rare in the animal kingdom. While species such as great apes, dolphins, elephants, and some birds—like magpies—can pass the mirror test, most animals either ignore their reflection or react as if encountering another individual. This highlights fundamental differences in self-awareness across species.

Do Animals Recognize Themselves in a Mirror?

The Science of Light: From White to RGB

When a beam of white light, composed of three converging monochromatic sources—red, green, and blue—passes through a slit, it is decomposed into its constituent colors. This results in three distinct vertical bands—red, green, and blue—which are projected onto a screen.

If an obstacle, such as a vertical wooden rod, is placed before the slit, it partially blocks some of the light components. As a result, three vertical stripes—cyan, magenta, and yellow—appear at the location of the slit. These colors are the complements of the original light sources and emerge through subtractive color mixing:

  • Cyan appears where red is blocked.
  • Magenta appears where green is blocked.
  • Yellow appears where blue is blocked.

By moving the rod, one can control which complementary color passes through the slit. This complementary color then cancels out its corresponding primary color behind the slit. For example, if magenta passes through, it eliminates green from the screen.

The concept of additive color mixing can be confusing for those who aren’t familiar with artistic or design principles. This is because people are generally more accustomed to subtractive color mixing, which is how colors blend in the physical world, such as when mixing pigments like paints or inks. In contrast, the additive color model describes how light produces color.

The Soul of Books: A Journey from Bark to Pages

I must have been born in a library, for the love I hold for books is immeasurable. A book awakens all the senses in me: the visual pleasure, the tactile warmth, the scent of cinnamon or vanilla from old pages, the soft rustle of turning leaves, and even the taste… To me, no digital book will ever replace the presence of a real one, with its soul and essence.

But the journey from tablet to scroll, to codex, and finally to the modern book spans millennia. The codex, the direct ancestor of today’s book, introduced a revolutionary format—pages bound along one edge—laying the foundation for how we read and store knowledge today.

Books, as we recognize them, became widespread during the Middle Ages, largely due to Gutenberg’s invention of the printing press. However, the codex itself dates back much further. It was made of sheets folded multiple times, often twice, to form a bifolio. These bifolia were sewn together into gatherings, allowing for binding and, when needed, rebinding. The most common structure consisted of four bifolia—eight sheets, totaling sixteen pages—known in Latin as quaternio. This term later gave rise to quaderno in Italian, cahier in French, and quire in English. Interestingly, the Latin word codex originally meant a block of wood, a nod to the materials once used for writing.

Even the word book has deep roots—its Old English form, bōc, likely stems from the Germanic root bōk-, meaning beech. This isn’t just a linguistic coincidence; early writings may have been carved into beech wood. In Slavic languages, the word for “letter,” буква (bukva), shares this origin. In Russian, Serbian, and Macedonian, букварь (bukvar’) or буквар (bukvar) refers to a child’s first reading textbook.

Similarly, the Latin word liber, which gave rise to libro in Italian and livre in French, originally meant “bark,” reinforcing the deep connection between books and trees. The Greek root biblio, is believed to be derived from βύβλος (búblos), meaning “papyrus,” named after the ancient Phoenician city of Byblos, a major hub of the papyrus trade.

From carved wood and tree bark to bound pages and printed volumes, books have always been deeply rooted in nature—both in language and in form.

The ‘Sassy Sparkler’ Sea Worm: Nature’s Deep-Sea Light Show

While exploring the Chile Margin along South America’s coastline, researchers made a dazzling discovery with their robotic explorer, ROV SuBastian: the iridescent ‘sassy sparkler‘ sea worm.

At first glance, this deep-sea polychaete worm appears unremarkable with its bristly body. But as it moves, its shimmering bristles reflect light, creating a pink iridescent glow. The secret lies in nanoscale structures within the bristles that act like prisms, scattering light to produce shifting colors depending on the angle of view.

This optical illusion not only mesmerizes but also serves practical purposes. The worm’s changing hues help with camouflage, communication, and UV protection in the deep ocean.

Polychaetes like the ‘sassy sparkler’ play essential roles in marine ecosystems, thriving in extreme environments like hydrothermal vents and contributing to nutrient cycling in ocean depths.

Through the Eyes of Insects

The compound eye is nothing like the human eye, but we often misunderstand how insects see the world. In horror movies, their vision is depicted as a chaotic kaleidoscope. In reality, it’s much more refined—like viewing the world through a crystal-clear glass paperweight. 

What’s even more fascinating? Some insects have vibrant color patterns on their compound eyes that serve a purpose! These patterns act as filters, enhancing contrast to help them spot objects against colorful backgrounds or shielding their eyes from certain wavelengths of light.

Take the Deer Fly and Horse Fly, for example—both flaunt these functional designs. But the Green Lacewing (Chrysopidae) takes the crown for the wildest look. Its compound eyes create a diffraction pattern resembling a sheriff’s star, formed by the countless six-sided “ommatidia” that make up its eye structure.

The Wonders of Compound Eyes

Insect compound eyes are made up of thousands of tiny units called ‘ommatidia’, each acting like a mini-eye. This gives insects a near-panoramic view, perfect for spotting motion and environmental changes. Dragonflies, for example, have around 30,000 ommatidia per eye, making them masters of motion detection.

While human eyes, with their single lens and dense photoreceptors, excel at detail and depth, they lack the wide-field motion awareness of compound eyes. Insects also outshine us in speed, detecting rapid movements crucial for survival.

Many insects see ultraviolet light—something humans can’t. This unique vision aids in finding food, communication, and mating. Compound eyes are a brilliant mix of structure and function!

Gliding Patterns: The Anomalous Motion Illusion

Let your gaze wander across the image below. Do the shapes in the first and third rows seem to subtly shift leftward, while the second and fourth rows appear to glide rightward?

© Gianni A. Sarcone, Gliding Patterns, 1999

Now, let your gaze wander across the image below. Do the concentric circles appear to subtly counter-rotate?

© Gianni A. Sarcone, Counter-Rotating Circles, 1999

Why do these static images appear to move? This perceptual phenomenon, known as “anomalous motion” or “peripheral drift illusion”, results from the interplay of color contrast, luminance, and eye movements. It occurs due to a sawtooth luminance grating in the visual periphery, where a sequence of contrasting colors transitions from light to dark. The speed of the perceived motion is influenced by the frequency of microsaccadic eye movements.

In the 1990s, I began creating many of these fascinating images, experimenting with patterns and contrasts to bring this mesmerizing effect to life.

Fine art prints and merchandise of these mesmerizing pieces are available in my online gallery—a perfect addition to any space!

Mesmerizing Color-Changing Squid

Squids are basically the chameleons of the sea, and their secret weapon? Chromatophores—tiny skin cells that let them pull off some mind-blowing color changes. Whether it’s blending into a coral reef or throwing out some serious “back off” vibes, these little guys do it all. Right now, though, this squid seems to be saying: “Hey genius, put me back in the water before you turn me into calamari!”

Chromatophores of the Squid: How Do They Work?
Chromatophores are pigment-containing cells found in the skin of squids and other cephalopods. These cells expand and contract to display different colors, allowing the squid to blend into its surroundings, communicate with others, or signal threats. They play a vital role in the squid’s survival.