Monday, June 30, 2014

Adolf Furtwängler and Photographic Archeology

Adolf Furtwängler
(1853 - 1907)
On June 30, 1853, German archaeologist and historian Adolf Furtwängler was born. He revolutionized archeological science with his use of photography for documentation. His use of photography in research supplanted the use of drawings because a camera gives objective reproduction with more accuracy, which enabled fragments to be scrutinized, even when they were miles apart.

Adolf Furtwängler grew up in a very educated family. His father was a classical scholar and schoolmaster. And also Adolf Furtwängler studied at the University of Leipzig and published his dissertation on "Eros in der Vasenmalerei". In the following years, he worked in Italy and Greece, financially supported by the German Archeological Institute and was able to join Heinrich Schliemann’s excavations at Olympia. He completed his habilitation in 1878 under Reinhard Kekulé in Bonn. In 1879 he published together with his colleague Georg Loeschcke, "Mykenische Thongefäße", a complete publication of the Mycennean pottery finds on Aegina, which was not only a valuable chronology but the first corpus of pottery finds in archaeology. This groundbreaking study established the difference between Mycenaean and Geometric pottery and contributed to the developing technique of identifying archaeological strata.

As his reputation grew, Furtwängler received several job offers and was appointed assistant director at the Royal Museums of Berlin and as a privatdozent at the University of Berlin. In 1885, Furtwängler's two-volume "Beschreibung der Vasensammlung im Antiquarium" (Writings on Vase Paining in Antiquity) appeared, a book describing over four thousand objects in a manner still emulated today. In the following years, Furtwängler published numerous brilliant works, he issued a study on Greek gems and their inscriptions, renewed the excavations at the temple of Aphaia in Aigina, and began issuing a corpus of Greek vases along with Karl W. Reichhold. Furtwängler also embarked on writing a history of ancient art, but contracted a case of dysentery in Aigina and died at age 54, cutting short a brilliant career. His students formed the most eminent of the next generation of classical art historians and archaeologists including Ludwig Curtius, Oskar Waldhauer, Georg Lippold, and Eduard Schmidt.

In his active working years, photography was already widely established, but it was not used very often in scientific documentations. Most archeologists still relied on detailed drawings, however, a truly accurate and objective reproduction was only possible with a camera. Inspired by Johannes Overbeck, Furtwänger also began using photographs. His work "Masterpieces of Greek Sculpture" contained numerous large format images and Furtwängler managed to establish the art of photography in archeology. Photography enabled fragments to be compared closely, even when they were miles apart. Perhaps the most famous example of Furtwängler's use of photography to reconstruct a statue, and identify it with descriptions by ancient authors, was the Athena which three authors say Pheidias cast in bronze for the islanders of Lemnos to dedicate on the Athenian Acropolis in the mid-5th century. Furtwängler was able to demonstrate that a marble head in Bologna belonged to a marble body in Dresden. The plaster cast in Oxford unites the two. Furtwängler concluded that the whole corresponded to descriptions by Pausanias and others of the 'fair' Athena who wore no helmet. The principal problem besetting the study of Greek sculpture was not the fragmentary condition but the lack of originals. Although ancient sources named famous sculptors and mentioned, or even described their work, most of the examples known to the 19th century were copies.

At yovisto, you may be interested in a short video lecture on the History of Photography.



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Sunday, June 29, 2014

Rembert Dodoens and the Love for Botanical Science

Rembert Dodoens (1516-1585)
On June 29, 1516, Flemish physician and botanist Rembert Dodoens (Dodonaeus) was born. His seminal work Stirpium historiae pemptades sex sive libri XXX (1583) is considered one of the foremost botanical works of the late 16th century. He divided plants into 26 groups and introduced many new families.

Rembert Dodoens was born under the name Rembert Van Joenckema in Mechelen, Spanish Netherlands, today Flanders, Belgium. Later, he changed it to Dodoens (“son of Dodo”), Dodo being a form of the first name of his father, Denis Van Joenckema. The name was latinized into Dodonaeus, from which the French, who were ignorant of its origins, further transformed it into Dodonée. Dodoens studied at the municipal college of Mechelen and went from there to the University of Louvain in 1530, where he studied medicine, cosmography and geography. According to the custom of the time, Dodoens then traveled extensively. Between 1535 and 1546 he was in Italy, Germany, and France. After these Wanderjahren he returned to Mechelen.

In 1548 Dodoens published a first book on cosmography, while in the same year he became one of the three municipal physicians of Mechelen. During this time Dodoens composed a treatise on physiology (published later) and began his botanical works. In the beginning of the sixteenth century, it was still believed that no plants existed other than those described by Dioscorides in his Materia medica of the first century AD. The great progress of natural sciences in the sixteenth century was helped by the discovery of printing and by the use of wood-block illustrations. Dodoens was a follower of the leading botanists of his time: Otto Brunfels and Sprengel, the “German fathers of botany,” as well as Jerome Bock and Leonhard Fuchs. In 1552, Dodoens’ first botanical work De frugum historia was published, a short treatise on cereals, vegetables, and fodders. In 1554, Dodoens also published, as Cruydeboek, a Dutch version of Leonard Fuchs' De stirpium historia, a national herbarium devoted to species indigenous to the Flemish provinces with 715 images. The merit of this book was that rather than proceeding by alphabetical order, as Fuchs had done, Dodoens grouped the plants according to their properties and their reciprocal affinities. Dodoens treated in detail especially the medicinal herbs, which made this work, in the eyes of many, a pharmacopoeia. The book was translated first into French in 1557 by Charles de L'Ecluse (Histoire des Plantes), into English (via L'Ecluse) in 1578 by Henry Lyte (A new herbal, or historie of plants), and later into Latin in 1583. In his times, it was the most translated book after the Bible.

Dodonea viscosa,  named in honor of Rembert Dodoens
Dodoens turned down a chair at the University of Leuven in 1557. In 1574 he left Mechelen for Vienna, where he had been appointed physician to the emperor Maximilian II. In Cologne, he published in one volume a dissertation on wine and medical observations (1980) and synoptic tables on physiology (1581). Then, he went to Antwerp, where in 1582 he supervised the printing of his Stirpium historiae pemptades sex sive libri XXX. In this elaborate treatise, Dodoens’ most important scientific work, he divided plants into twentysix groups and introduced many new families, adding a wealth of illustration. He then became professor in medicine at the University of Leiden in 1582, and remained there until his death. Dodoens is commemorated in the plant genus Dodonaea, which was named after him by Carolus Linnaeus.

At yovisto, you can learn more about botany in the video lecture on 'Human Livelihoods Depend on Wild Flowers: Kew’s Millennium Seed Bank explained'.


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Saturday, June 28, 2014

Maria Goeppert Mayer and the Nuclear Shell Model

Maria Goeppert Mayer (1906-1972)
On June 28, 1906, German-born Physicist Maria Goeppert Mayer was born. She was awarded the Nobel Prize in Physics for proposing the nuclear shell model of the atomic nucleus. She was the second female Nobel laureate in physics, after Marie Curie.

Maria Goeppert was born in Kattowitz, a city in Prussia, the only child of Friedrich Goeppert and his wife Maria. At age 4, she moved with her family to Göttingen when her father was appointed as the professor of pediatrics at the University of Göttingen. Goeppert was educated at the Höhere Technische Schule in Göttingen, a school for middle-class girls who aspired to higher education. In 1921, she entered the Frauenstudium, a private high school run by suffragettes that aimed to prepare girls for university. This school closed its doors during the economic inflation, but the teachers continued to give instructions to the pupils. Maria Goeppert finally took the abitur examination in Hannover, in 1924, being examined by teachers she had never seen in her life.

In the Spring of 1924, Goeppert entered the University of Göttingen, where she studied mathematics. A purported shortage of women mathematics teachers for schools for girls led to an upsurge of women studying mathematics at a time of high unemployment, and there was even a famous female professor of mathematics at Göttingen, Emmy Noether. But, most girls were only interested in qualifying for their teaching certificate and not in scientifc research. But, soon Maria Goeppert found herself more attracted to physics than to mathematics. This was the time when quantum mechanics was young and exciting. Thus Goeppert chose to pursue a Ph.D. in theoretical physics. In her 1930 doctoral thesis she worked out the theory of possible two-photon absorption by atoms. There were three Nobel Prize winners on the doctoral committee, Max Born, James Franck and Adolf Windaus. Nobel Laureate Eugene Wigner later described the thesis as "a masterpiece of clarity and concreteness".

At the time, the chances of experimentally verifying her thesis seemed remote, but the development of the laser permitted the first experimental verification in 1961 when two-photon-excited fluorescence was detected in a europium-doped crystal. To honor her fundamental contribution to this area, the unit for the two-photon absorption cross section is named the Goeppert Mayer (GM) unit. Shortly before she had met Joseph Edward Mayer, an American Rockefeller fellow working with James Franck. In 1930 she went with him to the Johns Hopkins University in Baltimore. This was the time of the depression, and no university would think of employing the wife of a professor. But she kept working, just for the fun of doing physics. There was little interest in quantum mechanics at Johns Hopkins, but Goeppert Mayer worked with Karl Herzfeld, collaborating on a number of papers. In 1939, Mayer took up a position at Columbia University, where the chairman of the Physics Department, George Pegram, arranged for Goeppert Mayer to have an office, but again she received no salary. Nevertheless, she had the chance to work together with physicist Enrico Fermi. In December 1941, Goeppert Mayer took up her first paid professional position, teaching science part-time at Sarah Lawrence College, and soon after she joined the Manhattan Project, where she researched the chemical and thermodynamic properties of uranium hexafluoride and investigated the possibility of separating isotopes by photochemical reactions. In February 1945, Goeppert Mayer decided to join Edward Teller's research group at the Los Alamos Laboratory.

In the late 1940s, Goeppert Mayer developed a mathematical model for the structure of nuclear shells, which she published in 1950. Her model explained why certain numbers of nucleons in an atomic nucleus result in particularly stable configurations. These numbers are what Eugene Wigner called magic numbers. Three German scientists, Otto Haxel, J. Hans D. Jensen, and Hans Suess, were also working on solving the same problem, and arrived at the same conclusion independently. In 1963, Goeppert Mayer, Jensen, and Wigner shared the Nobel Prize for Physics "for their discoveries concerning nuclear shell structure." She was the second female Nobel laureate in physics, after Marie Curie.

At yovisto you may enjoy the video 'The three lives of Marie Curie' by Dr. Serge Plattard.




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Friday, June 27, 2014

Sophie Germain and the Chladni Experiment

Sophie Germain
(1776 – 1831)
On June 27, 1831, French mathematician, physicist, and philosopher Marie-Sophie Germain passed away. She is best known for her work in number theory and contributions to the applied mathematics of acoustics and elasticity. Her work on Fermat's Last Theorem provided a foundation for mathematicians exploring the subject for hundreds of years after. Because of prejudice against her gender, she was unable to make a career out of mathematics, but she worked independently throughout her life.

There is not much known about Sophie Germain's early life. Many historians believe that she was the daughter of a pretty wealthy silk merchant while others assume, her father used to be a goldsmith. Clear is however, that she was born in 1776 in Paris. When the French Revolution started in France, Germain was 13 years old and it is widely assumed that she had to stay inside due to safety reasons and that she spent a lot of time in her father's library to keep herself entertained. Among the books that attracted her interest the most was apparently J. E. Montucla's "L'Histoire des Mathématiques". Next to mathematics, the young woman also started to teach herself in Greek and Latin in order to understand the works of Newton and Euler. Furtherly, it is believed that Germain studied "Le Calcul Différentiel" by Jacques Antoine-Joseph Cousin, who highly encouraged her in her studies during a visit. However, it is widely assumed that Gemain had lots of trouble convincing her parents from her new passions, who first did not approve her studies and apparently even took away her materials until realizing that she was really serious about it.

When the École Polytechnique opened, Sophie Germain was about 18 years old and of course, as a woman not allowed to attend any courses. However, she managed to study the lecture notes and started sending own works to the faculty member Joseph Louis Lagrange under the name of a former student. When Lagrange requested a meeting with the student, her real identity was revealed and luckily, the scientist became her mentor, impressed by Germain's brilliance. Soon, she started corresponding with Adrien-Marie Legendre in order to discuss number theory and later on also elasticity. Also the well established mathematician published some of her work in a later edition of the "Théorie des Nombres". In this period, Sophie Germain also started corresponding with Gauss who admired her courage and intelligence.

However, at some point, Gauss and Germain's correspondence stopped and she became more and more interested in the Ernst Chladni and his experiments. The German scientist is probably best known for his research on vibrating plates and the calculation of the speed of sound for different gases. Germain heard of a contest sponsored by the Paris Academy of Sciences concerning Chladni's experiments with vibrating metal plates and the goal was "to give the mathematical theory of the vibration of an elastic surface and to compare the theory to experimental evidence". Lagrange then commented that a solution to the problem would require the invention of a new branch of analysis and thus, Germain became the only person to enter the competition. After having submitted her paper in 1811, Germain did not win the prize even though "the experiments presented ingenious results". After two more extensions of the competition, Germain consulted the judge Denis Poisson, who shortly after published his own research results on elasticity, not mentioning Germain's help in any sentence. When Sophie Germain submitted her third work on the topic in 1816, she became the first woman to win a prize from the Paris Academy of Sciences even though the judges were again not completely satisfied as her method was not believed to be accurate enough and relied on incorrect equations from Euler. However, even though she had won the prize, Germain was still not able to attend the Academy's sessions as a woman until two years later, the befriended Joseph Fourier acquired tickets for her.

At yovisto, you may be interested in a video demonstration of the Chladni Experiments by Harvard University.



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Thursday, June 26, 2014

Lyman Spitzer and the Space Telescope

Lyman Spitzer (1914-1997)
photo: NASA
On June 26, 1914, American theoretical physicist, astronomer and mountaineer Lyman Strong Spitzer was born. Researching in star formation and plasma physics, he is probably best known for being the first to conceive the idea of telescopes operating in outer space. Thus, he is also the namesake of NASA's Spitzer Space Telescope.

Well mountaineer and astronomer at the same time, I guess we never had a fellow like Lyman Spitzer up to now. As a mountaineer, he made the first ascent of Mount Thor with David Morton in 1965. Never heard of Mount Thor or Thor's Peak? Well, it is part of the Baffin Mountains in Canada with an elevation of 1,675m. It features the Earth's greatest vertical drop of 1,250m, with the cliff overhanging at an average angle of 15 degrees from vertical. Despite its remoteness, this feature makes the mountain a popular rock climbing site. But, let's focus on Spitzer and his scientific work.

Lyman Spitzer was born to a Presbyterian family in Toledo, Ohio, the son of Lyman Strong Spitzer and Blanche Carey. Spitzer graduated from Scott High School, then attended Phillips Academy in 1929 and went on to Yale College, where he graduated in 1935 being a member of Skull and Bones. During a year of study at Cambridge University, he was influenced by Arthur Eddington and the young Subrahmanyan Chandrasekhar. Returning to the U.S., Spitzer earned his MA from Princeton University in 1937 and his PhD in 1938, under the direction of Henry Norris Russell.

Spitzer was just beginning his career when he published a short paper in 1946 — more than a decade before the launch of the first satellite. He proposed the development of a large, space-based observatory that would not be hindered by Earth's atmospheric distortion and span a broad range of wavelengths. According to a new theory in Spitzer's day, stars were powered by nuclear fusion. Calculations showed that our sun could burn for billions of years this way. But more massive stars would burn for only a few hundred million years. So, Spitzer theorized that stars were being created in the modern era, and that the intergalactic medium, a dark and mysterious place, held the reservoir of matter to create new stars. Scientists found evidence of this matter with large, ground-based optical telescopes. Yet the proof, Spitzer knew, would be found in the ultraviolet observations of young, hot stars. The Earth’s atmosphere blocks most ultraviolet radiation, so to observe these hot stars, scientists needed to send a UV detector above at least most of the atmosphere.

Spitzer continued to write seminal theoretical papers. Sounding rockets were piercing the atmosphere with X-ray and ultraviolet detectors, and a balloon carried an optical telescope above most of the atmosphere, as Spitzer had hoped. The showpiece of Spitzer's own space astronomy work at Princeton was NASA's Copernicus Orbiting Astronomical Observatory, launched in 1972. Spitzer was the principal investigator for this ultraviolet telescope. Copernicus did indeed find evidence of hot, young stars in dense clouds that block optical light but not all the ultraviolet light, and made many other key findings. The success of Copernicus helped secure Hubble's funding as well as Spitzer's legacy. By the 1970s, the astronomy community gave the "large space telescope" high priority in a major report, which led NASA to begin a Phase A study of a 3-meter telescope in 1973. More importantly, Spitzer helped convince Congress to fund the project, which ultimately became the 2.4-meter Hubble Space Telescope. Spitzer was instrumental in the design and development of the Hubble Space Telescope. Even after Hubble's launch in 1990, Spitzer remained deeply involved in the program. Not only did he make some important astronomical observations with the telescope that was essentially his brainchild, but he also spent a great deal of time — right up until the end of his life in 1997 — analyzing Hubble data.

At yovisto you can learn more the Hubble Space telescope based on Lyman Spitzer's idea. Observations made by the Hubble Space Telescope over the last two decades have given us significant new insights into our Universe.

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Wednesday, June 25, 2014

Hermann Oberth's Dream of Space Travel

Dr. von Braun and Professor Hermann Oberth are honored by the Berlin Technical University
1963
On June 25, 1894, Austro-Hungarian-born German physicist and engineer Hermann Oberth was born. He was the first, who when thinking about the possibility of spaceships grabbed a slide-rule and presented mathematically analyzed concepts and designs.

Maybe you have already heard of the 'Oberth Effect'. In interplanetary spaceflight, the Oberth effect is used in a powered flyby where the application of an impulse, typically from a rocket engine, close to a gravitational body can result in a higher change in kinetic energy and final speed. The effect is named after Hermann Oberth, who one of the founding fathers of rocketry and astronautics. Already in his youth, Hermann Oberth was highly influenced by the works of Jules Verne and increased his interests in rocket science and aeronautics ever since. He attempted a mathematical prove, that Jules Verne's "method" of shooting astronauts to the moon with a canon would not be possible and he came to realize that a journey to the moon could only be achieved with extremely powerful rockets. However, Oberth enrolled at the University of Munich studying medicine. In 1914, he joined the first World War and returned to the university in 1918. During the war, he designed his first rocket powered with ethanol and oxygen. One year later, he began his studies of physics and finished his dissertation on rockets, which was declined because there were no experts who could even evaluate his work. However, his work was published anyway in 1923 and faced a great success. In his work, Oberth published a description of all elements needed to create fuel for multistage rockets.

In 1927, the German amateur rocket association "Verein für Raumschiffahrt" was established. Hermann Oberth became a member and managed to network with numerous engineers interested in rocket technologies. The works of Oberth and his colleagues including Wernher von Braun, Ernst Stuhlinger, Helmut Gröttrup, and Walter Thiel in this period formed the foundations of rocket engineering and are considered the very early milestones in space flight. Oberth received the German citizenship in 1939 and worked under the name Fritz Hann at the Army Research Center in Pennemünde, Germany. There, he was also involved in the V2-Program. When the war was over, Oberth worked on several rocket-engineering projects in Switzerland, the USA and Germany. In this period, Oberth was involved in writing the study, "The Development of Space Technology in the Next Ten Years" and published his ideas on a lunar exploration vehicle, a "lunar catapult", and on "muffled" helicopters and airplanes. In 1960, Oberth returned to the USA as a technical consultant on the Atlas rocket program.

At yovisto, you may be interested in a historical documentation on Hermann Oberth and Wernher von Braun's achievements in rocketry and astronautics.



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Tuesday, June 24, 2014

Martin Perl and the Tau

Martin Lewis Perl (*1927)
photo: nobelprize.org
On June 24, 1927, American physicist and Nobel Laureate Martin Lewis Perl was born. He is best known for his discovery of the tau lepton, a subatomic massive particle with a negative charge. The tau, which he found in the mid-1970s, was the first evidence of a third "generation" of fundamental particles.

The tau lepton (τ, also called the tau particle, tauon or simply tau) is an elementary particle similar to the electron, with negative electric charge and a spin of 1⁄2, but with 3477 times the mass. Together with the electron, the muon, and the three neutrinos, it is classified as a lepton. Two main classes of leptons exist: charged leptons (also known as the electron-like leptons), and neutral leptons (better known as neutrinos). Charged leptons can combine with other particles to form various composite particles such as atoms and positronium, while neutrinos rarely interact with anything, and are consequently rarely observed. Tau leptons have a very short lifetime of 2.9×10−13 s and a mass of 1776.82 MeV/c2 (compared to 105.7 MeV/c2 for muons and 0.511 MeV/c2 for electrons). Since their interactions are very similar to those of the electron, a tau can be thought of as a much heavier version of the electron. Because of their greater mass, tau particles do not emit as much bremsstrahlung radiation as electrons; consequently they are potentially highly penetrating, much more so than electrons. However, because of their short lifetime, the range of the tau is mainly set by their decay length, which is too small for bremsstrahlung to be noticeable: their penetrating power appears only at ultra high energy.

Let's take a look on the discovery of the Tau and the man who succeeded to find it. Martin Perl was born on June 24, 1927 in New York City, New York to a family of Jewish emigrants to the US from the Polish area of Russia. Perl is a 1948 chemical engineering graduate of Brooklyn Polytechnic Institute. After graduation, he worked for the General Electric Company, as a chemical engineer in a factory producing electron vacuum tubes. To learn about how the electron tubes worked, Perl signed up for courses in atomic physics and advanced calculus at Union College in Schenectady, New York, which led to his growing interest in physics, and eventually to becoming a graduate student in physics in 1950.

Martin Perl received his Ph.D. from Columbia University in 1955, where his thesis described measurements of the nuclear quadrupole moment of sodium, using the atomic beam resonance method that his advisor Isaac I. Rabi had won the Nobel Prize in Phyics for in 1944. Perl spent 8 years at the University of Michigan, where he worked on the physics of strong interactions, using bubble chambers and spark chambers to study the scattering of pions and later neutrons on protons. Seeking a simpler interaction mechanism to study, Perl started to consider electron and muon interactions. He had the opportunity to start planning experimental work in this area when he moved in 1963 to the Stanford Linear Accelerator Center (SLAC), then being built in California. He was particularly interested in understanding the muon: why it should interact almost exactly like the electron but be 206.8 times heavier, and why it should decay through the route that it does. Perl chose to look for answers to these questions in experiments on high-energy charged leptons. In addition, he considered the possibility of finding a third generation of lepton through electron-positron collisions.

The tau was finally detected in a series of experiments between 1974 and 1977 by Perl with his colleagues at the SLAC-LBL group. They were able to collide electrons and positrons at higher energies than had previously been possible, initially at up to 4.8 GeV and eventually at 8 GeV, energies high enough to lead to the production of a tau/antitau pair. Because of the very short lifetime of the tau, these particles decayed within a few millimetres of the collision. Hence Perl and his coworkers did not detect the tau directly, but rather discovered anomalous events where they detected either an electron and a muon, or a positron and an antimuon. The symbol τ that was chosen for tau was derived from the Greek τρίτον (triton, meaning "third" in English), since it was the third charged lepton discovered. Martin Perl won the Nobel Prize in 1995 jointly with Frederick Reines. The prize was awarded "for pioneering experimental contributions to lepton physics". Perl received half "for the discovery of the tau lepton" while Reines received his share "for the detection of the neutrino"

At yovisto, you may learn more about particle physics in the inside tour of the world` biggest supercollider LCH at the CERN research institute, given by physicist Brian Cox.



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Monday, June 23, 2014

Deodat de Dolomieu and the Love for Rocks

Déodat de Dolomieu
(1750 – 1801
On June 23, 1750, French geologist Déodat Gratet de Dolomieu was born. He is best known for his field research in mineralogy. The mineral and the rock dolomite and the largest summital crater on the Piton de la Fournaise volcano were named after him.

Déodat de Dolomieu grew up in the Alps of southeastern France and showed early interest in his surrounding nature. However, he started a military career when he was only 12 years old and even fought a duel, killing a fellow member of the Maltese Order in later years. Soon, the young Dolomieu became known as highly attracted to women, especially among the nobility. He was made a corresponding member of the Royal Academy of Sciences and played a significant role in the intellectual progress of France. De Dolomieu spent much of his time collecting minerals and visiting mining areas and categorizing geological data across Europe. He had a great interest in volcanoes, but was soon convinced, that water played a major role in shaping the surface of the Earth through a series of prehistoric, catastrophic events.

During one of his voyages to the Alps of Tyrol, De Dolomieu discovered a calcareous rock which, unlike limestone, did not effervesce with weak hydrochloric acid. The geologist published his findings in the French science magazine "Journal de Physique" in 1791 and one year later, the rock was given the name dolomite by the Swiss chemist Nicolas-Théodore de Saussure. Still, De Dolomieu was not the first to describe the mineral, earlier descriptions came from Linnaeus, who was the first to note the fact that this rock resembled limestone but does not effervesce with dilute acid. In the meantime, Dolomieu advanced in rank in the Knights of Malta and was promoted to Commander in 1780. In the same year, he retired from active military service, partly due to the fact that his liberal political leanings which were unpopular among the conservative nobility, ruling the Order. From then on, De Dolomieu devoted all his life to science and traveling.

Around 1795, De Dolomieu accepted the position of Professor of Natural Sciences at the École Centrale Paris and started to write the mineralogical section of the Encyclopédie Méthodique. In the following year, he was appointed Inspector of Mines and Professor at the École Nationale Supérieure des Mines de Paris, where his portrait is still displayed in the library. His extensive mineral collection is today housed at the Muséum National d'Histoire Naturelle of Paris. Only three years after his career as professor started, De Dolomieu had developed a great international reputation and he was considered as one of the most important geologists of his time.

Napoleon Bonaparte, whom De Dolomieu supported since the beginning of the French Revolution, invited the scientist to join the expedition accompanying Bonaparte's invasion of Egypt, as part of the natural history and physics section of the Institut d'Égypte. Unfortunately for him, De Dolomieu fell ill and was forced to return home, but when his ship got caught in a heavy storm, he sought refuge in Italy, where he was then considered a prisoner of war. The imprisonment of a world-famous scientist, under such bad conditions, was abhorrent to the intellectual community of Europe. He was released in 1801 and immediately intended to resume his scientific studies, but due to heavy illnesses resulting from the imprisonment, Déodat de Dolomieu died on 28 November of the same year.

At yovisto, you may be interested in a video lecture by John merriman, who talks about Napoleon Bonaparte and the French Revolution, that highly influenced Deodat de Dolomieu thoughout his lifetime.



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Sunday, June 22, 2014

The Discovery of Charon

Artist's concept of Charon seen from the surface of Pluto
On June 22, 1978, US astronomer John Christy discovered Charon, the largest moon of Pluto. Although there was a discussion after the reclassification of Pluto as a dwarf, Charon is not in the list of dwarf planets currently recognized by the IAU.

On June 22, John Christy had examined the magnified images of the former planet Pluto, taken with the 61-inch Flagstaff telescope two months prior. He noticed a periodically appearing elongation, which was confirmed shortly after. During subsequent studies, it was determined that the bulge was due to a smaller accompanying body. Also, it was noticed that the periodicity of the bulge corresponded to Pluto's rotation period. Between 1985 and 1990, Pluto and Charon entered a five-year period of mutual eclipses and transits and all doubts about Charon could be abolished. A few weeks after the United States Naval Observatory astronomer James Christy had discovered Pluto's largest moon, Charon, his achievement was officially announced by the International Astronomical Union.

Charon is half a big as Pluto and it is assumed that its surface consists mostly of water ice. Also, scientists believe that Charon has no atmosphere. However, there are several theories on Charon's internal structure. It is believed that Charon was created by a giant impact into Pluto's icy mantle and that it therefore consists of an icy body, containing less rock by proportion than its partner Pluto. One theory suggests, that Charon has a rocky core and an icy mantle, others believe Charon to be of uniform composition throughout.

Pluto and Charon are considered gravitationally locked, which means that each object keeps the same face towards the other. Due to the fact that neither object orbits the other, many scientists argued that Charon should be considered as a dwarf planet itself, however, the International Astronomical Union stated that Charon is considered to be just a satellite of Pluto.

A side view of the Pluto-Charon system
Image: Stephanie Hoover

At yovisto, you may be interested in a video lecture on 'Pluto, Eris and the Dwarf Planets of the Outer Solar System' by Professor Mike Brown.



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Saturday, June 21, 2014

Franz Kruckenberg's Schienenzeppelin

Kruckenberg's Schienenzeppelin
Image: Franz Jansen
On 21 June 1931, Franz Kruckenberg's Schienenzeppelin (rail zeppelin) set a new world railway speed record of 230.2 km/h (143.0 mph) on the Berlin–Hamburg line between Karstädt and Dergenthin, which was not surpassed by any other rail vehicle until 1954.

The famous Schienenzeppelin was anticipated by the design of the Aerowagon, an experimental high-speed railcar fitted with an aircraft engine and propeller traction. The railcar from germany was built in 1930 near Hannover by Franz Kruckenberg and finished in fall of the same year. It was about 15m long and had two axles. Originally, the railcar had two conjoined BMW petrol aircraft engines powering a four bladed propeller. The body of the Schienenzeppelin was streamlined, having a great resemblance to the era's popular Zeppelin airships, and it was built of aluminum in aircraft style to reduce weight. The railcar could carry up to 40 passengers and its interior was designed in Bauhaus-style. On May 10, 1931 the railcar reached speeds of 200 km/h for the first time and this achievement was reported across the German media immediately. The great success on June 21 was achieved with Kruckenberg steering the rail zeppelin himself and afterwards, the vehicle was displayed in Berlin.

In 1932 Kruckenberg began a new project with the rail car involving significant modifications. It was given a completely new front end while the rear axle remained as it was. The aircraft engine was still used, but the power transmission was hydraulic through two Föttinger Fluid Drives for both directions of travel. Also, a pointed fairing was installed in place of the propeller. Kruckenberg completed this design in November 1932. During test drives in 1933, the new railway reached speeds of 180 km/h. Even though, Kruckenberg's designs never really went into 'mass' production, his designs found their way into later DRG railcar designs. His last version of the rail vehicle was produced in 1934 and it was sold to the Deutsche Reichsbahn (German Imperial Railway) and dismantled in in order to re-use its material for military purposes.

Unfortunately, the use of propellers in crowded railway stations was found too dangerous and due to its construction, it would have been difficult to pull additional wagons to form a train. Furthermore, Safety concerns have been associated with running high-speed railcars on old track network, with the inadvisability of reversing the vehicle, and with operating a propeller in close proximity to passengers.

The famous Schienenzeppelin in Berlin
Image: German Federal Archive


At yovisto, you may be interested in a historic video documentation on Kruckenberg's Schienenzeppelin.



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Friday, June 20, 2014

Gerald Hawkins and the Secret of Stonehenge

Stonehenge, photo: wikipedia
On June 20, 1928, English astronomer and author Gerald Stanley Hawkins was born. He is best known for his work in the field of archaeoastronomy. In 1965 he published an analysis of Stonehenge in which he was the first to propose its purpose as an ancient astronomical observatory used to predict movements of sun and stars.

Gerald Hawkins was born in Great Yarmouth and studied physics and mathematics at the University of Nottingham. In 1952 he took a PhD in radio astronomy, studying under Sir Bernard Lovell at the University of Manchester. In 1957 Hawkins became professor of astronomy and chairman of the department at Boston University in the United States. He wrote widely on numerous subjects, including tektites, meteors and the steady-state universe theory. Hawkins first saw Stonehenge in 1953, when working at nearby Larkhill camp. One of the most famous sites in the world, Stonehenge is the remains of a ring of standing stones set within earthworks. It is in the middle of the most dense complex of Neolithic and Bronze Age monuments in England and was built anywhere from 3000 BC to 2000 BC. Hawkins had read that the monument was aligned on midsummer sunrise, a fact first noted by William Stukeley in the 18th century, and made much of by Sir Norman Lockyer in 1906.

Hawkins applied the technological resources of the university to studying the astronomical alignments of ancient megalithic sites. He fed the positions of standing stones and other features at Stonehenge into an early IBM 7090 computer and used the mainframe to model sun and moon movements. This was at a time when computers were rare and glamorous. Asking that age's technological wonder to decipher the ancient world's icon was - according to The Guardian "a gesture of timely genius". The journal Nature published Hawkins's first results in 1963 and in his 1965 book, Stonehenge Decoded, Hawkins argued that the various features at the monument were arranged in such a way as to predict a variety of astronomical events. The computer, Hawkins argued, showed Stonehenge to be a neolithic "computer-observatory" for predicting eclipses of the sun and moon. All over the world, newspapers praised Hawkins and his computer for rewriting prehistory. Stone-age savages were revealed as skilled scientists.

By interpreting Stonehenge as a giant prehistoric observatory, Hawkins' work re-assessed what had previously been seen as a primitive temple. The archaeological community was no so happy with Hawkins' interpretation. His theories were criticized by such noted historians as Richard Atkinson, who denounced the book as being "...tendentious, arrogant, slipshod, and unconvincing". Atkinson himself had directed excavations at Stonehenge for the Ministry of Works between 1950 and 1964. Unfortunately because of an extremely heavy administrative burden arising from service on many committees throughout his career the written reports of the excavations at Stonehenge were not complete before his retirement.

However, Hawkins' book was a commercial success. It was especially popular amongst the members of 1960s counter culture, who found that it followed a similar "wisdom of the ancients" line explored by Alexander Thom, a Scottish engineer most famous for his theory of the Megalithic yard, categorization of stone circles and his studies of Stonehenge and other archaeological sites. Hawkins' theories still inform popular opinion of Stonehenge although archaeologists are cautious to accept them. Many scholars accept that the importance of astronomical alignment and large complexes being planned and constructed to fulfill cosmology has been demonstrated at other prehistoric sites, such as the Snake Mound and Cahokia in the United States.

Hawkins later examined the Nazca lines in Peru, and concluded there was not enough evidence to support an astronomical explanation for them. He also studied the temple of Amun at Karnak. He continued to study Stonehenge up until his death in 2003.

At yovisto you can learn more about Stonehenge in the lecture of Prof. Jeanne Willette from Otis College of Art and Design on "Stonehenge"



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Thursday, June 19, 2014

Ernst Boris Chain and his Research on Antibiotics

Sir Ernst Boris Chain (1906-1979)
On June 19, 1906, German-born British biochemist and Nobel Laureate Sir Ernst Boris Chain was born. He is best known for being one of the founders of chemical and medical research on antibiotics, esp. on Penicillinum.
"Science, as long as it limits itself to the descriptive study of the laws of nature, has no moral or ethical quality and this applies to the physical as well as the biological sciences." (Sir Ernst Boris Chain, in 'Social Responsibility and the Scientist', New Scientist, 22 October 1970, 166.)
Ernst Boris Chain was born in Berlin, the son of Margarete (née Eisner) and Michael Chain, a Russian-born Jewish immigrant who became a chemical engineer and built a successful chemical plant. The death of Michael Chain in 1919, coupled with the collapse of the post-World War I German economy, depleted the family's income so much that Margarete Chain had to open up her home as a guesthouse. One of Chain's primary interests during his youth was music, and for a while it seemed that he would embark on a career as a concert pianist. Ernest B. Chain was educated at the Luisengymnasium, Berlin, where he soon became interested in chemistry, stimulated by visits to his father's laboratory and factory. He next attended the Friedrich-Wilhelm University, Berlin, where he graduated in chemistry in 1930. He was from an early age interested in biochemistry and after graduation he worked for three years at the Charité Hospital, Berlin, on enzyme research.

After the Nazis came to power, Chain knew that he, being Jewish, would no longer be safe in Germany. He left Germany and moved to England, arriving on 2 April 1933 with ₤10 in his pocket. Geneticist and physiologist J.B.S Haldane helped him obtain a position at University College Hospital, London. He began working on phospholipids (a major component of all major biological membranes) as a PhD student at Fitzwilliam House, Cambridge University under the direction of Sir Frederick Gowland Hopkins. In 1935, he accepted a job at Oxford University as a lecturer in pathology. During this time he worked on a range of research topics, including snake venoms, tumor metabolism, lysozymes, and biochemistry techniques.

In 1939, he joined Howard Florey to investigate natural antibacterial agents produced by microorganisms - among them penicillin. This led him and Florey to revisit the work of Alexander Fleming, who had described penicillin nine years earlier. They mistakenly thought these substances were all enzymes like lysozyme. While Florey and Chain were assembling grants to support their research, work was begun on penicillin. Chain and Florey went on to discover penicillin's therapeutic action and its chemical composition. He also theorized the structure of penicillin, which was confirmed by X-ray crystallography done by Dorothy Hodgkin. For this research, Chain, Florey, and Fleming received the Nobel Prize in 1945. Chain, along with another chemist, Edward Penley Abraham, worked out a successful technique for purifying and concentrating penicillin. The keys seemed to lie in controlling the pH of the “juice,” reducing the sample’s temperature, and evaporating the product over and over (essentially freeze-drying it). In this early process many gallons of mold broth were used to produce an amount just large enough to cover a fingernail. This excruciatingly inefficient process was later improved on by Norman Heatley — another biochemist on the research team assembled by Florey — and a succession of other scientists.

Towards the end of World War II, Chain learned his mother and sister had perished in the war. Soon after World War II, Chain moved to Rome, to work at the Istituto Superiore di Sanità (Superior Institute of Health). There, he productively combined a biochemical research department and a fermentation pilot plant. In 1957 a consulting relationship with a group of scientists from the Beecham Group, who came to Rome especially to benefit from Chain’s biochemical insights and the facilities there, resulted in the isolation of the atomic groupings central to the penicillin molecule. He returned to Britain in 1964 as the founder and head of the biochemistry department at Imperial College London, where he stayed until his retirement, specializing in fermentation technologies. In honor of his scientific achievements he was knighted soon after in 1969. Always a person of many interests and projects, in his later life, his Jewish identity became increasingly important to him. He became a member of the board of governors of the Weizmann Institute of Science in 1954, and later a member of the executive council. His views were expressed most clearly in his speech ‘Why I am a Jew’ given at the World Jewish Congress Conference of Intellectuals in 1965.

At yovisto you can learn more about infectious diseases and the importance of penicillin from a lecture by Dr. Lucy Shapiro from Berkeley on 'Emerging Infectious Diseases and Global Health'.



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If you like the daily blog posts of yovisto about the history of science, please support us by clicking on the amazon links and making your next amazon purchase via our offered links. Nevertheless, please do also support your local (real world) bookstore at the corner of the street.