The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but: ‘That’s funny...’
—Isaac Asimov
Horace Walpole coined the word serendipity in a letter to Horace Mann. The two men had become friends during Walpole’s Grand Tour of Europe in 1739. Walpole returned to England a year later while Mann remained in Florence as Britain’s permanent envoy, a position he secured with assistance from Walpole’s father. The two men never met again but corresponded for forty-six years.
In one of his letters, Walpole wrote:
I once read a silly fairy tale, The Three Princes of Serendip. As their highnesses traveled they were always making discoveries, by accidents and sagacity, of things they were not in quest for: for instance, one of them discovered that a mule blind of the right eye had traveled the same road lately, because the grass was eaten only on the left side where it was worse than on the right — now do you understand serendipity?
The Travels and Adventures of the Three Princes of Serendip first appeared in a fourteenth century Persian poem by Amir Khusrau. The mule that Walpole recalled from childhood had actually been a one-eyed lame camel, driven by a woman and laden with bags of butter and honey. Given these clues, the prince deduced the path the lost camel had taken. The camel was found, the princes richly rewarded. The tale was translated from Persian to Italian in 1557, from Italian to French in 1619, and then to English in 1721. The story of the wayward one-eyed camel may be traced back to the sixth century Talmud, the princes replaced by Jewish slaves, the butter and honey, by wine and oil.
The Abecedary
A is for the first aniline dye, stumbled upon in 1856 by the 18-year-old English chemist Henry Perkin whose German tutor asked him to synthesize quinine from coal tar. Perkin ended up with a dirty brown sludge. After cleaning his beaker with alcohol, he noticed that the sludge had turned purple. Patented and marketed as Perkin’s Mauve, it was exhibited publicly by Empress Eugénie thereby becoming highly fashionable and making Perkin rich. His tutor synthesized another aniline dye, magenta, and helped to create the huge German dye industry. Sir William Henry Perkin was knighted in 1906 and quinine itself was first synthesized in 1944, just in time for its use in World War II. Mauve was not alone among serendipitous synthetic dyes: Prussian blue was accidentally hit upon in 1706, Scheele’s Green in 1775, Monastral blue in 1927, Pyrrole red in 1974, and Yin Mn blue in 2009. Serendipity comes in many colors.
B is for Botox. The powerful toxin produced by botulism bacteria was introduced to medicine by Alan B. Scott. His experimental drug, a form of the toxin later called Botox, was approved in 1989 for treating eye muscle problems, but often found off-label targets such as migraine headache or urinary incontinence. Its bonanza application arose by chance when Jean Carruthers saw her patient’s facial wrinkles vanish after treating her with Botox. For years she and her husband explored the many cosmetic applications of Botox. Once approved for such purposes, Botox became a multi-billion dollar drug, but the Carrothers had neglected to patent its cosmetic use.
C is for Cisplatin, the trade name for a chemical first synthesized in 1844 and called Peyrone’s salt. A century later, the American chemist Barnett Rosenberg set out to explore the effect of electricity on bacterial growth by sending electric currents through media containing live bacteria. Noticing that the cells stopped dividing, Rosenberg hoped that electricity might be used to treat cancer, but the suppression of cell division had resulted from a compound produced at their platinum electrodes. Rosenberg identified Peyrone’s salt as the most effective such platinum compound. Cisplatin arrived at clinics in 1978 to treat testicular and ovarian cancers. It is often used off label for other cancers. Cisplatin, along with several other platinum-based drugs, account for about forty percent of all effective chemotherapeutic agents.
D is for Dynamite, devised by Alfred Nobel in 1867. Two decades earlier, Ascanio Sobrero had created the liquid explosive nitroglycerine. Due to its instability, he could find no practical use for it. Nobel sought a material that could absorb nitroglycerine thereby yielding a stable solid that could safely be shaped, transported and triggered. He tried many materials – sawdust, cement, charcoal – but with no success. The serendipity of Nobel’s discovery lay in his fortuitous use of sand from dunes near his lab as his absorbent material – not the sand of ocean beaches nor that used to make concrete or fill children’s sandboxes, but kieselguhr, a diatomaceous earth made of ancient fossilized organisms. You can buy it as a health food or an insecticide and it gave rise to Nobel’s prize-creating discovery. Incidentally, symptoms often reported by nitroglycerine workers led to its serendipitous use to treat angina. Late in life Nobel was prescribed nitroglycerine pills for heart disease.
E is for chemical elements discovered more or less by chance. Nine of the prenuclear ninety-two elements qualify: Helium, Phosphorus, Oxygen, Argon, Iodine, Yttrium, Lanthanum, Praseodymium and Neodymium. Three more are found among the twenty-six transuranic elements: Neptunium, Einsteinium and Fermium. Phosphorus was discovered by alchemist Hennig Brand in 1669. He found it by distilling urine in quest of the Philosopher’s Stone. Three centuries later phosphorus bombs helped destroy his hometown of Hamburg. Lanthanum and didymium were chanced upon in 1840 when Carl Mosander tried to purify cerium. Both were regarded as elements and included in Mendeleev’s Table, but forty-five years later Carl von Weisbach was amazed to find didymium to be an alloy of two new elements, which he named Praseodymium and Neodymium.
F is for fission of the nuclear sort. Enrico Fermi’s Nobel Prize was awarded in part “for his demonstrations of the existence of new radioactive elements.” Believing he had produced elements ninety-three and ninety-four, Fermi named them Ausenium and Hesperium. He was wrong. Fermi had misinterpreted his own observations. After attending the Nobel ceremonies in Stockholm, Fermi and his family emigrated to the United States. Upon arriving in New York, Fermi learned that Hahn, Meitner and Strassmann had performed an experiment much like his own, but had found their results puzzling. Having fled Germany for Sweden, Meitner and her nephew Otto Frisch coined the phrase “nuclear fission” for what Hahn had observed but not understood. Fermi constructed the world’s first nuclear reactor in 1942 and became associate director of the Los Alamos National Laboratory in 1944, the same year Hahn won the Nobel Prize “for his discovery of the fission of heavy atomic nuclei.” Had Fermi not made his serendipitous error in 1934, the Nazis might have built a nuclear bomb in time to win World War II.
G is for Gamma ray bursts. When the US, UK, and USSR signed the 1963 Limited Test Ban Treaty banning nuclear tests in the atmosphere or in space, the U.S. Air Force began launching ever more sensitive VELA satellites to detect Soviet violations of the treaty. None were seen. In 1967, Vela 3 and Vela 4 observed puzzling flashes of Gamma rays coming from the heavens above, not the Soviet Union below. Vela spotted many more such events, but the anomalous data were of no interest to the military. When the data were made public, astrophysicists realized that Vela’s puzzling events, now called Gamma ray bursts, originated in galaxies billions of light-years away. They release far more energy in a few seconds than our sun will produce in its lifetime. Other than quasars and black hole mergers, no other cosmic cataclysms are as powerful.
H is for Helicobacter pylori. Doctors once believed that peptic ulcers and gastritis were due to stress or diet. In the early 1980s, Dr. Robin Warren saw that the severity of his patients’ disease was correlated with the number of curiously corkscrewed bacteria found in their stomachs. He and Barry Marshall set out to culture the novel bacteria. This they could not do until they accidentally left a biopsy sample in an incubator over a long Easter weekend. Serendipity taught them that H. pylori grew very slowly. Once they were cultured, Marshall, whether by accident or design, ate some and soon developed gastritis. The two doctors shared the 2005 Nobel Prize for “their discovery of Helicobacter pylori and its role in gastritis and peptic ulcer disease.”
I is for Infrared radiation. William Herschel left Germany for England in 1757 to pursue a career in music and his hobby of astronomy. After composing twenty-four symphonies, Hershel’s career and his hobby switched places and he became England’s most famous astronomer and telescope builder. In 1800, he briefly turned his attention to a puzzling question in physics: which color of sunlight carries the most heat? Using a prism, he allowed different colors to fall upon an array of thermometers. He was amazed to find that a thermometer he had carelessly left past the red end of the spectrum displayed the highest temperature. His lucky accident revealed the invisible form of light we call infrared. One year later, Johann Ritter, inspired by Herschel’s discovery, sought and found another invisible form of radiation, one lying beyond the violet end of the spectrum. Much later, radio waves and microwaves were found beyond infrared; and X-rays and Gamma rays beyond ultraviolet.
J is for Jumping genes and the revolutionary work of Barbara McClintock. In the 1940s, genes were believed to have fixed locations on their chromosomes. McClintock was surprised to discover that the patterns of colored kernels on corn cobs do not always follow predictable Mendelian inheritance patterns. She concluded that genes could jump about on their chromosomes during meiosis. Her discovery was not widely accepted until the 1970s, when it was found that most organisms have genes that jump. Biologists call them transposons and have learned the important roles they play in evolution and oncogenesis. Barbara McClintock earned the National Medal of Science in 1970, the Wolf Prize in 1981 and the 1983 Nobel Prize for “her discovery of mobile genetic elements.”
K is for Kevlar, accidentally created in 1965 by Dupont chemist Stephanie Kwolek. While trying to develop a lighter alternative to steel, she created a cloudy water-like fluid. When she finally convinced a co-worker to spin her fluid, its liquid portion evaporated and the remaining material polymerized into liquid crystal fibers five times stronger than steel. These fibers are woven into belts, ropes or fabrics. Named Kevlar by Dupont, it is widely used for tires, body armor, and other protective gear. Kwolek’s awards include the National Medal of Technology and Invention, the Perkin and Lavoisier Medals, and inclusion in the National Women’s Hall of Fame.
L is for the psychedelic drug LSD first synthesized by the Swiss chemist Albert Hofmann in 1938 as he was searching for a respiratory restorative. Because it elicited little interest, he ignored his new chemical for years. On April 19, 1943, while re-synthesizing LSD, he accidentally ate some of it. Feeling a bit woozy, he asked his laboratory assistant to accompany him as he bicycled home. During his ride he experienced the world’s first LSD trip. The drug was explored for possible therapeutic use, but its widespread abuse led the FDA to classify it an illegal hallucinogen. It remains accessible legally only for LSD-assisted clinical trials. Habitual trippers celebrate April 19 as their own psychedelic holiday, Bicycle Day. Hofmann won the Scheele award for his discovery in 1971, the same year that the United Nations declared his drug to be illegal everywhere.
M is for Microwave ovens, invented at Raytheon by Percy Spenser, a self-taught engineer working on radar technology. While using a live source of microwave radiation, he was surprised to find that a candy bar in his pocket had melted. He was sufficiently intrigued by the effect to figure out how to use microwaves to cook eggs, make tea, or pop popcorn. The microwave oven was patented by Spenser and Raytheon in 1945. The first clumsy and costly models were marketed in 1947, but by 2024 the global microwave oven market value had surged past $13 billion.
N is for Neoprene, the first widely used synthetic rubber, discovered accidentally by Arnold Collins while he was working with Wallace Carothers at DuPont. Carothers’ group was searching for a substitute for natural rubber; and after learning of Father Julius Nieland’s creation of small acetylene polymers, Carothers focused his group’s attention on acetylene-based polymers. He tried to synthesize the linear trimer divinyl-acetylene but obtained a contaminated result. He charged Collins with purifying the highly reactive fluid. Collins managed to extract a small sample of an unknown liquid contaminant, which he placed in a sealed test tube. Soon afterward Collins found the liquid to have congealed into a small ball which bounced. The novel liquid was chlorophene, which had self-polymerized into polychlorophene, what we know as neoprene – a synthetic rubber in use for almost a century in gaskets, gloves, washers, wetsuits, hoses, and home insulation.
O is for Ozempic, trade name for semaglutide. Developed and marketed by Novo Nordisk, it was approved in 2017 for treating diabetes. When many doctors began prescribing Ozempic off-label for its serendipitous side effect of promoting weight loss, Novo Nordisk produced a formulation of semaglutide – Wegovy – adapted specifically for weight management. The development of semaglutide depended on two other bits of serendipity: the creative use of gila monster venom and sexually dimorphic fish. Ozempic and Wegovy became and remain multi-billion dollar drugs. The 2025 Breakthrough Prize in Life Sciences was awarded to five of semaglutide’s developers.
P is for Pulsars, discovered in 1967 by Jocelyn Bell, then a doctoral student under Anthony Hewish. While measuring quasars, she discovered a rapidly pulsating radio source. Hewish initially dismissed her claim, but by the year’s end she had spotted four such puzzling sources, now known as pulsars. Her serendipitous discovery was published in 1968 as ‘A New Rapidly Pulsating Radio Source’ by A. Hewish, J. Bell, et al. But what were these sources? Astronomer Thomas Gold discovered the answer in 1969: they were rotating neutron stars. Hewish won half the 1974 Nobel Prize for “his decisive role in the discovery of pulsars.” It was a prize that Jocelyn Bell Burnell surely deserved to share. In 2018, she won the Special Breakthrough Prize in Fundamental Physics, donating the £3 million award to the Institute of Physics to support graduate education in science. Dame Jocelyn Bell Burnell currently serves as rector of Brunel University and Professorial Fellow at Oxford.
Q is for Quantum Dots (Qdots). The 2023 Nobel Prize was shared by Moungi Bawendi, Louis Brus, and Alexie Yekimov “for the discovery and synthesis of quantum dots,” nanoparticles with unique and useful optical and electronic properties. In 1982, Yekimov created quantum dots as colloids in glass. Unlike his co-laureates, he denies any trace of serendipity in his work. Later that year Brus, working at Bell Labs on the possible uses of semiconductors as catalysts, accidentally produced Qdots as colloids in a liquid medium. Unable to repeat his success, the idea struck him that the old medium, now depleted, may have been oxidized. With a fresh supply, he could reliably resynthesize the Qdot colloid. Bawendi also claimed a serendipitous boost when he noticed a Qdot solution changing color overnight. Qdots lie in the domain between quantum and classical physics, having extensive applications in healthcare, lighting, energy, and display technologies.
R is for Radioactivity. Months after the discovery of X-rays, Henry Becquerel conjectured that luminescent compounds emit X-rays as well as light upon being exposed to sunlight. To test his idea, he placed some luminescent crystals atop a photographic plate that had been wrapped in black paper so that light could not reach it. On a sunny day, he placed this setup outdoors in the sun. After a few hours, he unwrapped the plate in a darkroom and developed it. The plate revealed an image of the crystals even though no light had reached the plate. He announced to the French Academy that he had confirmed his hypothesis. Being a careful scientist, Becquerel tried to repeat his experiment. He prepared a fresh setup and stored it in a dark desk drawer to await another sunny day. After several cloudy days, he retrieved his setup and developed the plate. He was astonished to find that the plate again showed an image of the crystals. Becquerel realized that his luminescent crystals, which happened to be a uranium compound, emit a novel form of penetrating radiation which has nothing to do with sunlight, X-rays or luminescence. Retracting his week-old error, he announced his revised discovery to the Academy on March 1, 1896. Marie Curie showed that the novel radiation emerged spontaneously from uranium and thorium atoms. She named the effect radioactivity. Becquerel’s finding was multiply serendipitous: what if he had not kept his setup together for those dark days nor developed the hidden plate? What if he had used a different luminescent material or if the Paris sky had cleared?
S is for synthetic sweeteners, a subject rife with serendipity for nearly a century:
1879: Constantin Fahlberg, working with coal tar derivatives, returns home for dinner to find the sweet taste of Saccharin on his fingers!
1937: While Michael Sveda was working with an antipyretic drug he retrieved his lit cigarette from the lab bench and noticed the sweet taste of cyclamates.
1965: James Schlatter, seeking a new anti-ulcer medication blended two amino acids and, for reasons unknown, tasted the mix and found it sweet. It was Aspartame, now known as Equal.
1967: Karl Clauss, working on novel chemicals tasted one as he was cleaning a spill from his shirt. He had discovered acesulfane-K, now found in Coke, Pepsi, and Dr. Pepper-Zero.
1976: Shashikant Phadnis, searching for new uses of sucrose, was asked to test a novel compound: on tasting what he tested, he discovered Sucralose.
2000: Neotame and Advantame were developed without serendipity. Both are far sweeter than their predecessors. Will one of them win the Synthetic Sweetener Sweepstakes?
T is for Trinitrotoluene. German chemist Julius Wilbrand discovered the yellow powder in 1863 and marketed it as a fabric dye. Another German chemist, Carl Haussermann, discovered its explosive properties in 1892. TNT had many advantages as a filling for artillery shells. The German army adopted it in 1902, the British in 1907, the Americans in 1916. One year later a cargo boat laden with explosives for the French military set out from New York City en route to Bordeaux. On stopping in Halifax, the boat exploded in the largest man-made explosion prior to 1945. About 90 percent of its cargo was picric acid, the very sensitive but obsolescent predecessor of TNT. The explosion killed about 2,000 Canadians and injured 9,000 more.
U is for Uranus, spotted by chance in 1781 by William Herschel (yes, him again!) as he was compiling a stellar atlas. He thought it more likely to be a comet than a planet, but further observations and calculations by Johann Bode and others proved it to be the seventh planet. Bode named it Uranus while Herschel favored Georgium sidus. Not until 1850 did Bode decisively win the contest. Meanwhile, Uranus’ orbit was found to depart from Newtonian predictions. A failure of Newton’s laws? John Couch Adams in England and Urbain Leverrier in France each showed how the gravitational influence of an eighth planet could resolve the discrepancy. They explained where and when to search for it. Neptune was duly discovered in 1845 and Newton’s laws confirmed. Four years later, Le Verrier found a significant discrepancy in Mercury’s orbit, a puzzle that remained a problem until the advent of Albert Einstein’s general theory of relativity.
V is for Viagra (sildenafil), which was discovered at Pfizer in 1989 and intended to treat angina and hypertension. Welshmen enrolled in early clinical trials were seen to turn on their stomachs whenever nurses passed their beds. One nurse realized that the men were embarrassed by their erections. Pfizer wisely chose Viagra as the trade name, with ‘vi’ from virile or vigorous and ‘agra’ from the rushing waters of Niagara Falls. It was approved for the treatment of erectile dysfunction in 1998.
W is for the Whitehead manifold, one of many accidental discoveries in mathematics. Oxford mathematician J.H.C. Whitehead announced his proof of the Poincaré’s conjecture in 1934. A year later, he found the fatal flaw in his reasoning and retracted his proof. Instead, he had discovered something he was not looking for and was widely believed not to exist: a contractible 3-dimensional non-Euclidean space. Now known as the Whitehead manifold, its existence revealed the fascinating but unexpected complexity of geometric topology. Poincaré’s conjecture was demonstrated by the reclusive Russian mathematician Grigori Perelman, one year shy of a century after it had been proposed.
X is for Xenon, one of the six noble (or rare) gases. In 1939, Captain Albert Behnke, while studying the breathing problems of deep-sea divers, accidentally discovered xenon’s anesthetic property. It is now a favored anesthetic for some high-risk patients. In 1962, British Chemist Neil Bartlett found platinum hexafluoride to be an oxidizing agent so powerful that it steals electrons from oxygen molecules. Noticing that oxygen’s ionization potential was nearly that of xenon, he realized that PtF6 might react with xenon, even though he had been taught that noble gases are entirely inert. It did react, yielding a red-orange powder. Bartlett had succeeded in synthesizing the world’s first stable noble gas compound, xenon hexafluoroplatinate Xe[PtF6], a feat generations of chemistry students had been taught was impossible. Hundreds of noble gas compounds have been created since, most of them stable only at very low temperatures. Noble gas solids have potential applications for quantum computers and sensors. Krypton fluoride lasers are already used for deep-ultraviolet photolithography, xenon tetrafluoride for dry etching silicon microchips.
Y is for the yellow fever vaccine created by Max Thieler, for which he won the 1951 Nobel Prize. His discovery was a classic instance of serendipity. His decade-long journey to attenuate the virus causing yellow Fever, involved passing the virus from one animal or animal tissue to another. After 176 passages, Thieler was met with the sudden and surprising appearance of a fully attenuated mutant virus, Thieler’s 17D strain. After another hundred or so serial passages, Thieler became convinced that his ultimate variant of the 17D strain was perfectly safe, stable and effective. His vaccine was released in 1937 and remains widely used. A single dose generally provides lifelong immunity.
Z is for Zymurgy, the study of fermentation with ‘zym’ from the Greek for yeast. Louis Pasteur, the first zymurgist, claimed in 1857 that sucrose is anaerobically converted into ethanol and CO2 by living yeast cells. Wilhelm Kuhne coined the word enzyme in 1878 for biological agents that catalyze chemical reactions whether inside or outside living cells. It was then uncertain whether fermentation was caused by living yeast cells as Pasteur had insisted or by cell-free enzymes that living yeast cells produce. In 1897, Eduard Buchner tried to extract materials from yeast for his own immunological research. He compressed a quantity of finely ground yeast cells to obtain a cell-free extract, using sugar to preserve it as we use sugar to preserve fruit. Buchner was amazed when his extract began to bubble! He realized that his cell-free yeast extract ferments sucrose into alcohol and carbon dioxide. Pasteur had been mistaken.
