Caption: The authors measured the relative scale and spacing of the whirling brush strokes in van Gogh’s “The Starry Night,” along with variances in luminance of the paint, to see if the laws that apply in the physics of real skies apply in the artist’s depiction. The results suggest van Gogh had an innate understanding of atmospheric dynamics. He captured multiple dimensions of atmospheric physics with surprising accuracy. Credit: Yinxiang Ma
Vincent van Gogh’s painting “The Starry Night” depicts a swirling blue sky with yellow moon and stars. The sky is an explosion of colors and shapes, each star encapsulated in ripples of yellow, gleaming with light like reflections on water.
Van Gogh’s brushstrokes create an illusion of sky movement so convincing it led atmospheric scientists to wonder how closely it aligns with the physics of real skies. While the atmospheric motion in the painting cannot be measured, the brushstrokes can.
In an article published this week in Physics of Fluids, by AIP Publishing, researchers specializing in marine sciences and fluid dynamics in China and France analyzed van Gogh’s painting to uncover what they call the hidden turbulence in the painter’s depiction of the sky.
“The scale of the paint strokes played a crucial role,” author Yongxiang Huang said. “With a high-resolution digital picture, we were able to measure precisely the typical size of the brushstrokes and compare these to the scales expected from turbulence theories.”
To reveal hidden turbulence, the authors used brushstrokes in the painting like leaves swirling in a funnel of wind to examine the shape, energy, and scaling of atmospheric characteristics of the otherwise invisible atmosphere. They used the relative brightness, or luminance, of the varying paint colors as a stand-in for the kinetic energy of physical movement.
“It reveals a deep and intuitive understanding of natural phenomena,” Huang said. “Van Gogh’s precise representation of turbulence might be from studying the movement of clouds and the atmosphere or an innate sense of how to capture the dynamism of the sky.”
Their study examined the spatial scale of the painting’s 14 main whirling shapes to find out if they align with the cascading energy theory that describes the kinetic energy transfer from large- to small-scale turbulent flows in the atmosphere.
They discovered the overall picture aligns with Kolmogorov’s law, which predicts atmospheric movement and scale according to measured inertial energy. Drilling down to the microcosm within the paint strokes themselves, where relative brightness is diffused throughout the canvas, the researchers discovered an alignment with Batchelor’s scaling, which describes energy laws in small-scale, passive scalar turbulence following atmospheric movement.
Finding both scalings in one atmospheric system is rare, and it was a big driver for their research.
“Turbulence is believed to be one of the intrinsic properties of high Reynolds flows dominated by inertia, but recently, turbulence-like phenomena have been reported for different types of flow systems at a wide range of spatial scales, with low Reynolds numbers where viscosity is more dominant,” Huang said.
“It seems it is time to propose a new definition of turbulence to embrace more situations.”
Matthew Rozsa provides a more accessible description of the research in a September 20, 2024 article for Salon.com, Note: Links have been removed,
… one can look at “The Starry Night” and see a scientifically accurate representation of turbulent, cascading waters — a visual that may have directly inspired van Gogh before he transposed those dynamics into his iconic starry sky while painting in his mental asylum room in the French town of Saint-Rémy-de-Provence.
“Imagine you are standing on a bridge, and you watch the river flow. You will see swirls on the surface, and these swirls are not random.” Yongxiang Huang, lead author of the study, told CNN. “They arrange themselves in specific patterns, and these kinds of patterns can be predicted by physical laws.”
Scientists fascinated by van Gogh’s art are not limited to physicists. When researchers discovered a gecko that reminded them of the paintings of van Gogh, they gave it the scientific name Cnemaspis vangoghi. As a common terms, the authors suggested “van Gogh’s starry dwarf gecko.”
Here’s a link to and a citation for the paper,
Hidden turbulence in van Gogh’s The Starry Night by Yinxiang Ma (马寅翔), Wanting Cheng (程婉婷), Shidi Huang (黄仕迪), François G. Schmitt, Xin Lin (林昕), Yongxiang Huang (黄永祥). Physics of Fluids Volume 36, Issue 9 September 2024 DOI: https://doi.org/10.1063/5.0213627
Mark Lorch’s, Professor of Science Communication and Chemistry at the University of Hull (UK), April 29, 2024 essay on The Conversation (h/t April 30, 2024 news item on phys.org) provides an interesting account of the dangers associated with literature, Note: Links have been removed,
In our modern society, we rarely consider books to be dangerous items. However, certain books contain elements so hazardous that they require scrutiny before being placed on the shelves of public libraries, bookstores or even private homes.
The Poisonous Book Project [also known as, Poison Book Project], a collaborative research project between Winterthur Museum, Garden & Library and the University of Delaware, is dedicated to cataloguing such books. Their concern is not with the content written on the pages, but with the physical components of the books themselves — specifically, the colours of the covers.
The project recently influenced the decision to remove two books from the French national library. The reason? Their vibrant green cloth covers raised suspicions of containing arsenic.
This concern is rooted in historical practices in bookbinding. During the 19th century, as books began to be mass produced, bookbinders transitioned from using expensive leather covers to more affordable cloth items. To attract readers, these cloth covers were often dyed in bright, eye-catching colours.
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One popular pigment was Scheele’s green, named after Carl Wilhelm Scheele, a German-Swedish chemist who in 1775 discovered that a vivid green pigment could be produced from copper and arsenic. This dye was not only cheap to make, it was also more vibrant than the copper carbonate greens that had been used for over a century.
Scheele green eventually fell out of favour because it had a tendency to fade to black when it reacted with sulphur-based pollutants released from coal. But new dyes based on Scheele’s discovery, such as emerald and Paris green, proved to be much more durable. …
These pigments, however, had a significant drawback: they degraded easily, releasing poisonous and carcinogenic arsenic. The frequent reports of green candles poisoning children at Christmas parties, factory workers tasked with applying paint to ornaments convulsing and vomiting green water and warnings of poisonous ball dresses raised serious concerns about the safety of these green dyes.
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Green isn’t the only colour to worry about, however. Red is also of concern. The brilliant red pigment vermilion was formed from the mineral cinnabar, also known as mercury sulfide. This was a popular source of red paint dating back thousands of years. There is even evidence that neolithic artists suffered from mercury poisoning. Vermilion red sometimes appears on the marbled patterns on the inside of book covers.
Yellow has also caught the eye of the poisonous book project. In this case, the culprit is lead chromate. The bright yellow of lead chromate was a favourite with painters, not least Vincent van Gogh, who used it extensively in his most famous series of paintings: Sunflowers. For the Victorian-era bookbinders, lead chromate allowed them to create a range of colours from greens (achieved by mixing chrome yellow with Prussian blue) to yellows, oranges and browns.
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So what should you do if you come across a green cloth book from the 19th century? First, don’t be overly concerned. You would probably have to eat the entire book before you’d suffer from severe arsenic poisoning. However, casual exposure to copper acetoarsenite, the compound in the green pigment, can irritate the eyes, nose and throat.
It is more of a concern for folks who may regularly handle these books where frequent contact could result in more serious symptoms. Therefore, anyone who suspects they might be handling a Victorian-era book with an emerald green binding is advised to wear gloves and avoid touching their face. Then clean all surfaces afterwards.
Books are not usually thought of as hazardous objects, but you will want to be careful with these ones from the Melbourne Museum’s Rare Book Collection.
Poisonous heavy metals permeate their very fabric, and the last 150-odd years has done nothing to lessen their toxicity.
How did it happen though?
This is not some dastardly Name of the Rose-esque plot [a reference to Umberto Eco and his 1986 novel, The Name of the Rose] but rather a combination of fashion, vanity, and workers’ rights (or lack thereof) in the years following the Industrial Revolution.
And it has left a dangerous legacy for modern-day museums.
An immersive, 360° video of a painting versus a video of the actual location depicted in the painting elicit similar levels of “the sublime,” an experience closely associated with feelings of awe. Alice Chirico of Università Cattolica del Sacro Cuore di Milano, Italy, and colleagues present their findings in the open-access journal PLOS ONE on March 17, 2021.
For centuries, philosophers have debated the nature of the sublime, which can be thought of as an aesthetic experience evoked by stimuli that may be perceived as vast, powerful, or rare–such as a landscape or a storm. Psychologists often equate the sublime to awe, and to study it, many have used pictures or videos of natural scenes to induce the sublime in study participants.
Chirico and colleagues now report the first investigation into whether artistic and photorealistic representations of nature differ in evoking the sublime. They measured the emotional responses of 50 study participants before and after viewing immersive, 360° videos of Vincent Van Gogh’s The Starry Night and of Saint-Rémy-de-Provence, the natural location depicted in the painting.
Statistical analysis of the participants’ responses showed that both virtual-reality videos induced the sublime with similar intensity. However, they differed with regards to certain sub-dimensions of the sublime. For instance, the nature-based video evoked a greater sense of vastness and a greater perception of existential danger.
Moreover, while the videos elicited similar emotions, the nature-based video evoked feelings of fear and positive affect that were of significantly higher intensity than those elicited by the art-based video. Participants also reported a greater sense of being present in the nature-based video than in the art-based one.
These findings demonstrate the potential for virtual reality as a research tool to deepen understanding of the sublime and other complex phenomena. Because participants in this study were already familiar with The Starry Night, future work could explore how people’s prior acquaintance with stimuli might impact their experience of the sublime.
The authors add: “By using virtual reality, we provided the first empirical contribution to the enduring debate about whether nature or instead art is better at evoking the experience of the sublime. We found that both nature and art are effective elicitors, although they exhibit different nuances.”
Caption: Starry night Credit: Alice Chirico
Following on Starry night (the photo above), Vancouver’s Imagine Van Gogh opened on the weekend of March 20-21, 2021. Tickets have been selling quickly, they’ve attended hours and extended the show’s run to August 2021. You can find out more here in Vincent Plano’s March 17, 2021 article for the Daily Hive. His images are not particularly good but there are many of them, which gives you some idea about the show. Rebecca Bollwitt’s March 19, 2021 posting on Miss 604 offers fewer but better quality pictures.
Back to the sublime, here’s a link to and a citation for the paper,
From YouTube, Heijmans NV Published on Nov 12, 2014 Inspired by Vincent van Gogh’s work, the cycle path combines innovation and design with cultural heritage and tourism. The Van Gogh-Roosegaarde cycle path is being constructed by Heijmans from a design by Daan Roosegaarde and forms part of the Van Gogh cycle route in Brabant.
According to other sources, the path was inspired by van Gogh’s ‘Starry Night’. From a November 21, 2014 article by Elizabeth Montalbano for Design News (Note: A link has been removed),
The Dutch are known for their love of bicycling, and they’ve also long been early adopters of green-energy and smart-city technologies. So it seems fitting that a town in which painter Vincent van Gogh once lived has given him a very Dutch-like tribute — a bike path lit by a special smart paint in the style of the artist’s “Starry Night” painting.
Designed by artist Daan Roosegaarde of Studio Roosegaarde, the van Gogh-Roosegaarde bike path — in the Dutch town of Nuenen en Eindhoven, where van Gogh lived from 1883-1885 — is a kilometer long and features technologies developed as part of the Smart Highway project, a joint venture of the studio and Dutch infrastructure company Heijmans.
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A team of 12 designers and engineers worked on the project for eight months, while site production took 10 days. The opening of the path marked the official launch of the international van Gogh 2015 year.
The path uses stones painted with a smart coating that charges by the heat of the sun during the day and then glow at night for up to eight hours. When there is not enough sunlight during the day to charge the stones, the path can draw electricity from a solar panel installed nearby. There are also LEDs in the path that provides lighting.
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How does the technology work?
Despite my best efforts, I never did unearth a good technical explanation. There is some sort of photoluminescent powder or paint. I vote for a powder that’s been emulsified in a paint/coating. material. Somehow, this material is charged by sunlight and then at night glows with the help of a solar panel and light-emitting diodes (LEDs).
Here’s the clearest explanation I found; it’s from Dan Howarth’s November 12, 2014 article for dezeen.com (Note: A link has been removed), ,
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The surface of the Van Gogh-Roosegaarde Bicycle Path is coated with a special paint that uses energy gathered during the day to glow after dark.
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[Daan] Roosegaarde told Dezeen that this method of illumination is “more gentle to the eye and surrounding nature” that other lighting infrastructure, and creates a “connection with cultural history”.
A nearby solar panel is used to generate power to illuminate the coated surface, which was developed with infrastructure firm Heijmans. LEDs along the side of certain curves in the path cast extra light, meaning the path will still be partially lit if the weather has been too cloudy for the panel to charge the surface to its full brightness.
“It’s a new total system that is self-sufficient and practical, and just incredibly poetic,” said Roosegaarde.
The path is coated in photoluminescent paint that’s also embedded with small LEDs powered by nearby solar panels. The path essentially charges all day so that it can glow during the night, and it also has backup power in case it’s overcast.
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This October 30, 2012 article by Liat Clark for Wired.com provides a bit more detail about the powder/paint as Clark delves into the Roosegaarde Studo’s Smart Highway project (the cycle path made use of the same technology) ,
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The studio has developed a photo-luminising powder that will replace road markings – it charges up in sunlight, giving it up to 10 hours of glow-in-the-dark time come nightfall. “It’s like the glow in the dark paint you and I had when we were children,” designer Roosegaarde explained, “but we teamed up with a paint manufacturer and pushed the development. Now, it’s almost radioactive“. [perhaps not the wisest choice of hyperbole]
Special paint will also be used to paint markers like snowflakes across the road’s surface – when temperatures fall to a certain point, these images will become visible, indicating that the surface will likely be slippery. Roosegaarde says this technology has been around for years, on things like baby food – the studio has just upscaled it.
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Not everyone is in love
Shaunacy Ferro’s July 26, 2017 article for dentalfloss.com highlights a glow-in-the-dark path project for Singapore and a little criticism (Note: Links have been removed),
Glow-in-the-dark materials are no longer for toys. Photoluminescence can help cities feel safer at night, whether it’s part of a mural, a bike lane, or a highway. Glow-in-the-dark paths have been tested in several European cities (the above is a Van Gogh-inspired bike path by the Dutch artist Daan Roosegaarde) and in Texas, but now, the technology may be coming to Singapore. The city-state is currently developing a 15-mile greenway called the Rail Corridor, and it now has a glow-in-the-dark path, as Mashable reports.
The 328-foot stretch of glowing path is part of a test of multiple surface materials that might eventually be used throughout the park, depending on public opinion. In addition to the strontium aluminate-beaded [emphasis mine] path that glows at night, there are also three other 328-foot stretches of the path that are paved with fine gravel, cement aggregate, and part-grass/part-gravel. The glow-in-the-dark material embedded in the walkway absorbs UV light from the sun during the day and can emit light for up to eight hours once the sun goes down.
However, in practice, glow-in-the-dark paths can be less dazzling than they seem. [emphasis mine] Mashable’s reporter called the glowing effect on Singapore’s path “disappointingly feeble.” [emphasis mine] In 2014, a glowing highway-markings pilot by Studio Roosegaarde in the Netherlands revealed that the first road markings faded after exposure to heavy rains. [emphases mine] When it comes to glowing roads, the renderings tend to look better than the actual result, [emphasis mine] and there are still kinks to work out. (The studio worked the issue out eventually.) While a person walking or biking down Singapore’s glowing path might be able to tell that they were staying on the path better than if they were fumbling along dark pavement, it’s not the equivalent of a streetlight, for sure.
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Ferro had reported earlier on Studio Roosegaarde’s Smart Highway project in an October 23, 2014 article for Fast Company where Ferro first mentioned the rain problem (Note: Links have been removed),
Glowing Lanes is a collaboration between Dutch engineering company Heijmans and Daan Roosegaarde, a tech-loving artist and designer whose previous work includes Intimacy 2.0, a dress that becomes transparent when the wearer gets aroused. The glow-in-the-dark lane markers are intended to increase road visibility in a more energy-efficient way than traditional street lighting. Photoluminescent paint charges during the day and slowly emits light over the course of eight hours during the evening.
After a few technical challenges (an early version of the markers didn’t fare so well in the rain), the final system has been installed, and according to Studio Roosegaarde, the kinks have been worked out, and initial reports of the paint fading were “overstated.” [emphases mine]
“This was part of any normal learning process,” according to an email from the studio’s PR, and “now the project is ‘matured.’”
But not to the point where it’s no longer a novelty. According to the email from Studio Roosegaarde, the glowing highway caused a minor traffic jam last night as people rushed to look at it.
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… Roosegaarde has also been asked to create a smart highway design for Afsluitdijk–an almost 20-mile-long dike that connects North Holland to the province of Friesland across the water–and according to his studio, there are plans in the works to launch the glowing lanes in China and Japan as well.
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Comments
In the following excerpt, there’s a reference to strontium aluminate-coated materials, given the interview which follows this section, the project in Singapore did not use the photoluminescent paint developed by Roosegaarde Studio. I found this paint reference in a July 26, 2017 article by Yi Shu Ng for Mashable (h/t Ferro’s July 26, 2017 article) which notes the product’s ubiquity,
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The track glows because it’s got strontium aluminate compounds embedded in it — the chemical is commonly found in glow-in-the-dark products, which absorb ultraviolet light in the day, to emit luminescence at night.
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There are some inconsistencies in the reporting about the number of hours, eight hours or 10 hours, the bicycle path or smart highway remains lit after being charged. Given that this was a newish technology being used in a new application, the rain problem and other technical glitches were to be expected. I wish the writer had been a little less dismissive and that the studio had been a little more forthcoming about how they solved the problems. In any case, I dug further and this is what I got.
Interview
I’m not sure who answered the questions but this comes direct from Studio Roosegaarde,
Could you give me a capsule description of what’s happened since the path was opened in 2014/15? For example, How does the bike path look these days? Does it still glow? Don’t the bicycles on the path destroy the ‘Starry Night’ pattern over time? Do the stones have to be coated over and over again to maintain their solar charging capacities?
The Van Gogh Path is still working perfectly and is visited every night by couples, tourists and local people. The stones are inside the concrete so are still in place and will work for a minimum of 10 years. It is great to see we have created a place of wonder. It is the most published bicycle path in the world. We have even had children books published about it.
Are there more bike paths like the Van Gogh Path in other parts of Holland and/or elsewhere?
No, this is the only one. There have been some copycats in other countries.The Smart Highway project is still growing, and our recent Gates of Light is the next step of poetic and energy-neutral landscapes like the Van Gogh Path: https://www.studioroosegaarde.net/project/gates-of-light
How has your project evolved? And, have there been any unanticipated benefits and/or setbacks? Is there a change in the technology, I noticed you were investigating bioluminscence.
Yes, we are still developing new landscapes of the future. What we have learned from Van Gogh Path we have applied in new projects such as Glowing Nature: https://www.studioroosegaarde.net/project/glowing-nature We also do something new.
I was struck by how gentle the lighting is. I understand there has been some criticism about how much light the path radiates and I’m wondering about your thoughts on that.
Yes, since the path is a nature protected environment, normal LED lighting was not allowed. So the light is gentle but still visible, and sustainable.There are some bad copy-cats using cheap materials which don’t work well, like the one in Singapore. But we are happy that our path is still working.
Thank you to the folks at Studio Roosegaarde for taking the time to provide this interview. Here are links to Studio Roosegaarde and their industrial partner, Heijmans.
It has to be disconcerting to realize that your precious paintings are deteriorating day by day. In a June 22, 2017 posting titled ‘Art masterpieces are turning into soap‘,
A good art dealer can really clean up in today’s market, but not when some weird chemistry wreaks havoc on masterpieces [emphasis mine]. Art conservators started to notice microscopic pockmarks forming on the surfaces of treasured oil paintings that cause the images to look hazy. It turns out the marks are eruptions of paint caused, weirdly, by soap that forms via chemical reactions. Since you have no time to watch paint dry, we explain how paintings from Rembrandts to O’Keefes are threatened by their own compositions — and we don’t mean the imagery.
Here’s the video,
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Now, for the latest: canavases are deteriorating too. A May 23, 2018 news item on Nanowerk announces the latest research on the ‘canvas issue’ (Note: A link has been removed),
Paintings by Vincent van Gogh, Pablo Picasso and Johannes Vermeer have been delighting art lovers for years. But it turns out that these works of art might be their own worst enemy — the canvases they were painted on can deteriorate over time.
In an effort to combat this aging process, one group is reporting in ACS Applied Nano Materials (“Combined Nanocellulose/Nanosilica Approach for Multiscale Consolidation of Painting Canvases”) that nanomaterials can provide multiple layers of reinforcement.
One of the most important parts of a painting is the canvas, which is usually made from cellulose-based fibers. Over time, the canvas ages, resulting in discoloration, wrinkles, tears and moisture retention, all greatly affecting the artwork. To combat aging, painting conservators currently place a layer of adhesive and a lining on the back of a painting, but this treatment is invasive and difficult to reverse. In previous work, Romain Bordes and colleagues from Chalmers University of Technology, Sweden, investigated nanocellulose as a new way to strengthen painting canvases on their surfaces. In addition, together with Krzysztof Kolman, they showed that silica nanoparticles can strengthen individual paper and cotton fibers. So, they next wanted to combine these two methods to see if they could further strengthen aging canvas.
The team combined polyelectrolyte-treated silica nanoparticles (SNP) with cellulose nanofibrils (CNF) for a one-step treatment. The researchers first treated canvases with acid and oxidizing conditions to simulate aging. When they applied the SNP-CNF treatment, the SNP penetrated and strengthened the individual fibers of the canvas, making it stiffer compared to untreated materials. The CNF strengthened the surface of the canvas and increased the canvas’s flexibility. The team notes that this treatment could be a good alternative to conventional methods.
This image illustrating the researchers’ solution accompanies the article,
Courtesy: ACS
The European Union’s NanoRestART project was mentioned here before they’d put together this introductory video, which provides a good overview of the research,
For more details about the problems with contemporary and modern art, there’s my April 4, 2016 posting when the NanoRestART project was first mentioned here and there’s my Jan. 10, 2017 posting which details research into 3D-printed art and some of the questions raised by the use of 3D printing and other emerging technologies in the field of contemporary art.
I last wrote about ‘Woolly Thoughts” some years ago in a July 28, 2010 posting which focused on science knitting. Now, Alex Bellos has written an Oct. 3, 2016 posting for the Guardian about the ‘mathekniticians’ behind ‘Woolly Thoughts’,
In 1996 two British maths teachers active on an internet knitting forum were asked by a US yarn firm to design it an afghan.
“We were sent into a panic! We had no idea what an afghan was!” remembers Pat Ashforth, who with partner Steve Plummer is known in the crafts community for maths-inspired knits.
The couple soon discovered that an afghan was a knitted or crocheted blanket or throw. They produced four designs for the US firm, and it began a journey that has defined the rest of their lives.
Ashforth and Plummer decided that the afghan was the perfect canvas for expressing mathematical ideas – and since then they have devoted much of their time to producing as many as they can.
Together they have knitted and crocheted about 90 mathematical afghans (math-ghans?). Since each afghan takes about 100 hours to complete, this means the total time spent they have spent making them is about 9,000 hours (which adds up to 375 days – more than a year). And they have also made many other mathematical objects in wool.
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The couple met while teaching at a school in Luton. By 1999 they were both working at a school in Nelson, Lancashire, where they married in 2005. Originally the afghans were hung in their classrooms. “They were invaluable as a vehicle for talking about maths, says Ashforth. “Large, touchable, unbreakable items were perfect for encouraging group discussion. It is much easier for everyone to be looking at the same thing than for each individual to have their own separate book.”
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Not only are the images in the afghans mathematical, but the way they are made also involves mathematical thinking.
“We enjoy the challenge of seeing an idea then working out how it can be made into an afghan in a way that would be easy enough for anyone else to recreate. It is like trying to solve a puzzle and refining it to give the best possible solution.”
This is a great story from Bellos and it’s studded with images of the couple’s work.
Here are a few examples you won’t find embedded in Bellos’ posting,
Vincent: This illusion is based on Vincent Van Gogh’s Self-Portrait with Grey Felt Hat. The portrait was painted in 1887 and is in the Van Gogh Museum, Amsterdam. The colours in the illusion were chosen to reflect the impression of the painting but they are very subtle. If I was making it again I would choose slightly more contrasting colours for better definition of the face. Courtesy: Woolly Thoughts
QR Code: You have probably arrived at this page because you scanned the wall-hanging, or a photo of it, elsewhere. I have been thinking about knitting a large-scale QR code for several years. I wanted it to look as little like a QR code as possible, which is rather perverse as the whole purpose of a code is that people can instantly recognise it and scan it with a phone. Some of my ideas were very complicated and I could not be sure that they would work. Eventually I decided to try a simple version first. There may be others later. QR codes differentiate between light and dark so the actual colours don’t really matter. My first attempt, which I pulled undone, had many more colours than the final version. I thought it looked very messy so eventually settled for four dark, and four light, colours, on the principle of the ‘four-colour map theorem’. There is no pattern for this design. Courtesy: Woolly Thoughts
Mixed Mitrefours: All of the shapes are kites and are all exactly the same size. Four-sided shapes that are all the same will always fit together. This design is unusual because the kites are constructed in two different ways. You may see some 3D effects in the design. It seems to look different from each direction. Courtesy: Woolly Thoughts
You can find Woolly Thoughts here and the community and yarn/pattern database for knitters and crocheters where you can purchase the Woolly Thoughts patterns for a small cost, Ravelry can be found here.
This glowing reproduction of “The Starry Night” contains 65,536 pixels and is the width of a dime across. Credit: Ashwin Gopinath/Caltech
It may take you a few seconds (it did me) but it’s possible to see Van Gogh’s Starry Night in this image. A July 12, 2016 news item on ScienceDaily reveals more,
Using folded DNA [deoxyribonucleic acid] to precisely place glowing molecules within microscopic light resonators, researchers at Caltech have created one of the world’s smallest reproductions of Vincent van Gogh’s The Starry Night.
A July 12, 2016 Caltech news release (also on EurekAlert) by Richard Perkins, which originated the news item, provides more information about the image, DNA origami, and this latest research on coupling light emitters to photonic crystal cavities (Note: Links have been removed),
The monochrome image—just the width of a dime across—was a proof-of-concept project that demonstrated, for the first time, how the precision placement of DNA origami can be used to build chip-based devices like computer circuits at smaller scales than ever before.
DNA origami, developed 10 years ago by Caltech’s Paul Rothemund (BS ’94), is a technique that allows researchers to fold a long strand of DNA into any desired shape. The folded DNA then acts as a scaffold onto which researchers can attach and organize all kinds of nanometer-scale components, from fluorescent molecules to electrically conductive carbon nanotubes to drugs.
“Think of it a bit like the pegboards people use to organize tools in their garages, only in this case, the pegboard assembles itself from DNA strands and the tools likewise find their own positions,” says Rothemund, research professor of bioengineering, computing and mathematical sciences, and computation and neural systems. “It all happens in a test tube without human intervention, which is important because all of the parts are too small to manipulate efficiently, and we want to make billions of devices.”
The process has the potential to influence a variety of applications from drug delivery to the construction of nanoscale computers. But for many applications, organizing nanoscale components to create devices on DNA pegboards is not enough; the devices have to be wired together into larger circuits and need to have a way of communicating with larger-scale devices.
One early approach was to make electrodes first, and then scatter devices randomly on a surface, with the expectation that at least a few would land where desired, a method Rothemund describes as “spray and pray.”
In 2009, Rothemund and colleagues at IBM Research first described a technique through which DNA origami can be positioned at precise locations on surfaces using electron-beam lithography to etch sticky binding sites that have the same shape as the origami. For example, triangular sticky patches bind triangularly folded DNA.
Over the last seven years, Rothemund and Ashwin Gopinath, senior postdoctoral scholar in bioengineering at Caltech, have refined and extended this technique so that DNA shapes can be precisely positioned on almost any surface used in the manufacture of computer chips. In the Nature paper, they report the first application of the technique—using DNA origami to install fluorescent molecules into microscopic light sources.
“It’s like using DNA origami to screw molecular light bulbs into microscopic lamps,” Rothemund says.
In this case, the lamps are microfabricated structures called photonic crystal cavities (PCCs), which are tuned to resonate at a particular wavelength of light, much like a tuning fork vibrates with a particular pitch. Created within a thin glass-like membrane, a PCC takes the form of a bacterium-shaped defect within an otherwise perfect honeycomb of holes.
“Depending on the exact size and spacing of the holes, a particular wavelength of light reflects off the edge of the cavity and gets trapped inside,” says Gopinath, the lead author of the study. He built PCCs that are tuned to resonate at around 660 nanometers, the wavelength corresponding to a deep shade of the color red. Fluorescent molecules tuned to glow at a similar wavelength light up the lamps—provided they stick to exactly the right place within the PCC.
“A fluorescent molecule tuned to the same color as a PCC actually glows more brightly inside the cavity, but the strength of this coupling effect depends strongly on the molecule’s position within the cavity. A few tens of nanometers is the difference between the molecule glowing brightly, or not at all,” Gopinath says.
By moving DNA origami through the PCCs in 20-nanometer steps, the researchers found that they could map out a checkerboard pattern of hot and cold spots, where the molecular light bulbs either glowed weakly or strongly. As a result, they were able to use DNA origami to position fluorescent molecules to make lamps of varying intensity. Similar structures have been proposed to power quantum computers and for use in other optical applications that require many tiny light sources integrated together on a single chip.
“All previous work coupling light emitters to PCCs only successfully created a handful of working lamps, owing to the extraordinary difficulty of reproducibly controlling the number and position of emitters in a cavity,” Gopinath says. To prove their new technology, the researchers decided to scale-up and provide a visually compelling demonstration. By creating PCCs with different numbers of binding sites, Gopinath was able to reliably install any number from zero to seven DNA origami, allowing him to digitally control the brightness of each lamp. He treated each lamp as a pixel with one of eight different intensities, and produced an array of 65,536 of the PCC pixels (a 256 x 256 pixel grid) to create a reproduction of Van Gogh’s “The Starry Night.”
Now that the team can reliably combine molecules with PCCs, they are working to improve the light emitters. Currently, the fluorescent molecules last about 45 seconds before reacting with oxygen and “burning out,” and they emit a few shades of red rather than a single pure color. Solving both these problems will help with applications such as quantum computers.
“Aside from applications, there’s a lot of fundamental science to be done,” Gopinath says.
