Sunday, August 20, 2017

Some Anti-Fairy Tales

An anti-fairy tale, also called anti-tale, is a fairy tale which, unlike an ordinary one, has a tragic, rather than a happy ending, with the antagonists winning and the protagonists losing at the end of the story. Whereas fairy tales paint a magical, utopian world, anti-fairy tales paint a dark world of nastiness and cruelty. Such stories incorporate horror, black comedy, mean-spirited practical jokes on innocent characters, sudden and often cruel plot twists, and biting satire. The term (German: Antimärchen) was introduced by Andrè Jolles  in his Einfache Formen (1930).

Examples of anti-fairy tales include "The Fisherman and His Wife" and "The Swineherd". The term is also used to refer to remakes of traditional "happy" fairy tales into "unhappy" ones. The Shrek film series, which parodies and satirises fairy tales, includes several elements of anti-fairy tales such as the deaths of heroic characters and scatalogical humour.

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Example: The Fisherman and his Wife


There is a poor fisherman who lives with his wife in a hovel by the sea. One day the fisherman catches a golden flounder, which claims to be an enchanted prince, and begs to be set free. The fisherman kindly releases it. When his wife hears the story, she says he ought to have had the flounder grant him a wish, and insists that he go back and ask the flounder to grant her wish for a nice house.

The fisherman returns to the shore but is uneasy when he finds that the sea seems to becoming turbid, as it was so clear before. He makes up a rhyme to summon the flounder, and it grants the wife's wish. The fisherman is pleased with his new wealth, but the wife is not and demands more -- that her husband go back and wish that he be made a king. Reluctantly, he does, and gets his wish. But again and again, his wife sends him back to ask for more and more. The fisherman knows this is wrong but there is no reasoning with his wife. He says they should not annoy the flounder, and be content with what they have been given, but his wife is not content. Each time, the flounder grants the wishes, but each time the sea grows more and more fierce.

Eventually, the wife goes too far when she wishes to command the sun, moon and heavens, and become equal to God. When that final wish is made, the flounder undoes all the wishes, and returns the fisherman and his wife to their hovel. And with that, the sea becomes calm once more.

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Example: The Willful Child


Once upon a time there was a child who was willful and would not do what her mother wished. For this reason, God had no pleasure in her, and let her become ill. No doctor could do her any good, and in a short time the child lay on her deathbed. When she had been lowered into her grave, and the earth was spread over her, all at once her little arm came out again and reached upward. And when they had pushed it back in the ground and spread fresh earth over it, it was all to no purpose, for the arm always came out again. Then the mother herself was obliged to go to the grave and strike the arm with a rod. When she had done that, the arm was drawn in, and at last the child had to rest beneath the ground. And everything went back to normal.

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Example: Frau Trude


A willful little girl will not obey her parents and, having taken it into her head that she wants to see Frau Trude, goes in spite of all their warnings. She arrives terrified, and Frau Trude questions her. She tells of seeing a black man on her steps (a collier, says Frau Trude), a green man (a huntsman), a red man (a butcher), and, looking through her window, the devil instead of Frau Trude.

Frau Trude says she saw the witch in her proper attire, and that she had been waiting for the girl. She turned her into a block of wood and threw her onto the fire, and then warmed herself by it, commenting on how bright the block made the fire.

Saturday, August 19, 2017

Carnot, Father of Thermodynamics

Nicolas Léonard Sadi Carnot (1 June 1796 – 24 August 1832) was a French military engineer and physicist, often described as the "father of thermodynamics". In his only publication, the 1824 monograph Reflections on the Motive Power of Fire, Carnot gave the first successful theory of the maximum efficiency of heat engines. Carnot's work attracted little attention during his lifetime, but it was later used by Rudolf Clausius and Lord Kelvin to formalize the second law of thermodynamics and define the concept of entropy.

                                                              Sadi Carnot at age 17
Reflections on the Motive Power of Fire


When Carnot began working on his book, steam engines had achieved widely recognized economic and industrial importance, but there had been no real scientific study of them. Newcomen had invented the first piston-operated steam engine over a century before, in 1712; some 50 years after that, James Watt made his celebrated improvements, which were responsible for greatly increasing the efficiency and practicality of steam engines. Compound engines (engines with more than one stage of expansion) had already been invented, and there was even a crude form of internal-combustion engine, with which Carnot was familiar and which he described in some detail in his book. Although there existed some intuitive understanding of the workings of engines, scientific theory for their operation was almost nonexistent. In 1824 the principle of conservation of energy was still poorly developed and controversial, and an exact formulation of the first law of thermodynamics was still more than a decade away; the mechanical equivalence of heat would not be formulated for another two decades. The prevalent theory of heat was the caloric theory, which regarded heat as a sort of weightless and invisible fluid that flowed when out of equilibrium.

Engineers in Carnot's time had tried, by means such as highly pressurized steam and the use of fluids, to improve the efficiency of engines. In these early stages of engine development, the efficiency of a typical engine — the useful work it was able to do when a given quantity of fuel was burned — was only 3%.

Carnot cycle

Carnot wanted to answer two questions about the operation of heat engines: "Is the work available from a heat source potentially unbounded?" and "Can heat engines in principle be improved by replacing the steam with some other working fluid or gas?" He attempted to answer these in a memoir, published as a popular work in 1824 when he was only 28 years old. It was entitled Réflexions sur la Puissance Motrice du Feu ("Reflections on the Motive Power of Fire"). The book was plainly intended to cover a rather wide range of topics about heat engines in a rather popular fashion; equations were kept to a minimum and called for little more than simple algebra and arithmetic, except occasionally in the footnotes, where he indulged in a few arguments involving some calculus. He discussed the relative merits of air and steam as working fluids, the merits of various aspects of steam engine design, and even included some ideas of his own regarding possible improvements of the practical nature. The most important part of the book was devoted to an abstract presentation of an idealized engine that could be used to understand and clarify the fundamental principles that are generally applied to all heat engines, independent of their design.

Perhaps the most important contribution Carnot made to thermodynamics was his abstraction of the essential features of the steam engine, as they were known in his day, into a more general and idealized heat engine. This resulted in a model thermodynamic system upon which exact calculations could be made, and avoided the complications introduced by many of the crude features of the contemporary steam engine. By idealizing the engine, he could arrive at clear and indisputable answers to his original two questions.

He showed that the efficiency of this idealized engine is a function only of the two temperatures of the reservoirs between which it operates. He did not, however, give the exact form of the function, which was later shown to be (T1T2)/T1, where T1 is the absolute temperature of the hotter reservoir. (Note: This equation probably came from Kelvin.) No thermal engine operating any other cycle can be more efficient, given the same operating temperatures.

The Carnot cycle is the most efficient possible engine, not only because of the (trivial) absence of friction and other incidental wasteful processes; the main reason is that it assumes no conduction of heat between parts of the engine at different temperatures. Carnot knew that the conduction of heat between bodies at different temperatures is a wasteful and irreversible process, which must be eliminated if the heat engine is to achieve maximum efficiency.

Regarding the second point, he also was quite certain that the maximum efficiency attainable did not depend upon the exact nature of the working fluid. He stated this for emphasis as a general proposition:

The motive power of heat is independent of the agents employed to realize it; its quantity is fixed solely by the temperatures of the bodies between which is effected, finally, the transfer of caloric.

— Carnot 1890, p. 68

For his "motive power of heat", we would today say "the efficiency of a reversible heat engine", and rather than "transfer of caloric" we would say "the reversible transfer of entropy ∆S" or "the reversible transfer of heat at a given temperature Q/T". He knew intuitively that his engine would have the maximum efficiency, but was unable to state what that efficiency would be.

He concluded:

The production of motive power is therefore due in steam engines not to actual consumption of caloric but to its transportation from a warm body to a cold body.

— Carnot 1960, p. 7


In the fall of caloric, motive power evidently increases with the difference of temperature between the warm and cold bodies, but we do not know whether it is proportional to this difference.

— Carnot 1960, p. 15

In an idealized model, the caloric transported from a hot to a cold body by a frictionless heat engine that lacks of conductive heat flow, driven by a difference of temperature, yielding work, could also be used to transport the caloric back to the hot body by reversing the motion of the engine consuming the same amount of work, a concept subsequently known as thermodynamic reversibility. Carnot further postulated that no caloric is lost during the operation of his idealized engine. The process being completely reversible, executed by this kind of heat engine is the most efficient possible process. The assumption that heat conduction driven by a temperature difference cannot exist, so that no caloric is lost by the engine, guided him to design the Carnot-cycle to be operated by his idealized engine. The cycle is consequently composed of adiabatic processes where no heat/caloric ∆S = 0 flows and isothermal processes where heat is transferred ∆S > 0 but no temperature difference ∆T = 0 exist. The proof of the existence of a maximum efficiency for heat engines is as follows:

As the cycle named after him doesn't waste caloric, the reversible engine has to use this cycle. Imagine now two large bodies, a hot and a cold one. He postulates now the existence of a heat machine with a greater efficiency. We couple now two idealized machine but of different efficiencies and connect them to the same hot and the same cold body. The first and less efficient one lets a constant amount of entropy ∆S = Q/T flow from hot to cold during each cycle, yielding an amount of work denoted W. If we use now this work to power the other more efficient machine, it would, using the amount of work W gained during each cycle by the first machine, make an amount of entropy ∆S' > ∆S flow from the cold to the hot body. The net effect is a flow of ∆S' − ∆S ≠ 0 of entropy from the cold to the hot body, while no net work is done. Consequently, the cold body is cooled down and the hot body rises in temperature. As the difference of temperature rises now the yielding of work by the first is greater in the successive cycles and due to the second engine difference in temperature of the two bodies stretches by each cycle even more. In the end this set of machines would be a perpetuum mobile that cannot exist. This proves that the assumption of the existence of a more efficient engine was wrong so that an heat engine that operates the Carnot cycle must be the most efficient one. This means that a frictionless heat engine that lacks of conductive heat flow driven by a difference of temperature shows maximum possible efficiency.

He concludes further that the choice of the working fluid, its density or the volume occupied by it cannot change this maximum efficiency. Using the equivalence of any working gas used in heat engines he deduced that the difference in the specific heat of a gas measured at constant pressure and at constant volume must be constant for all gases. By comparing the operation of his hypothetical heat engines for two different volumes occupied by the same amount of working gas he correctly deduces the relation between entropy and volume for an isothermal process:

Reception and Philosophical Views

Carnot's book received very little attention from his contemporaries. The only reference to it within a few years after its publication was in a review in the periodical Revue Encyclopédique, which was a journal that covered a wide range of topics in literature. The impact of the work had only become apparent once it was modernized by Émile Clapeyron in 1834 and then further elaborated upon by Clausius and Kelvin, who together derived from it the concept of entropy and the second law of thermodynamics.

On Carnot's religious views, he was a Philosophical theist. As a deist, he believed in divine causality, stating that "what to an ignorant man is chance, cannot be chance to one better instructed," but he did not believe in divine punishment. He criticized established religion, though at the same time spoke in favor of "the belief in an all-powerful Being, who loves us and watches over us."

He was a reader of Blaise Pascal, Molière and Jean de La Fontaine.

Death and Ultimate Reputation

Carnot died during a cholera epidemic in 1832, at the age of 36. (Asimov 1982, p. 332) Because of the contagious nature of cholera, many of Carnot's belongings and writings were buried together with him after his death. As a consequence, only a handful of his scientific writings survived.

After the publication of Reflections on the Motive Power of Fire, the book quickly went out of print and for some time was very difficult to obtain. Kelvin, for one, had a difficult time getting a copy of Carnot's book. In 1890 an English translation of the book was published by R. H. Thurston; this version has been reprinted in recent decades by Dover and by Peter Smith, most recently by Dover in 2005. Some of Carnot's posthumous manuscripts have also been translated into English.

Carnot published his book in the heyday of steam engines. His theory explained why steam engines using superheated steam were better because of the higher temperature of the consequent hot reservoir. Carnot's theories and efforts did not immediately help improve the efficiency of steam engines; his theories only helped to explain why one existing practice was superior to others. It was only towards the end of the nineteenth century that Carnot's ideas, namely that a heat engine can be made more efficient if the temperature of its hot reservoir is increased, were put into practice. Carnot's book did, however, eventually have a real impact on the design of practical engines. Rudolf Diesel, for example, used Carnot's theories to design the diesel engine, in which the temperature of the hot reservoir is much higher than that of a steam engine, resulting in an engine which is more efficient.

Friday, August 18, 2017

The "Bone Wars": Marsh vs Cope

The Bone Wars, also known as the "Great Dinosaur Rush", was a period of intense and ruthlessly competitive fossil hunting and discovery during the Gilded Age of American history, marked by a heated rivalry between Edward Drinker Cope (of the Academy of Natural Sciences in Philadelphia) and Othniel Charles Marsh (of the Peabody Museum of Natural History at Yale). Each of the two paleontologists used underhanded methods to try to outdo the other in the field, resorting to bribery, theft, and destruction of bones. Each scientist also sought to ruin his rival's reputation and cut off his funding using attacks in scientific publications.

                                                   Marsh (left) and Cope (right)

Their search for fossils led them west to rich bone beds in Colorado, Nebraska, and Wyoming. From 1877 to 1892, both paleontologists used their wealth and influence to finance their own expeditions and to procure services and dinosaur bones from fossil hunters. By the end of the Bone Wars, both men had exhausted their funds in the pursuit of paleontological supremacy.

Cope and Marsh were financially and socially ruined by their attempts to outcompete and disgrace each other, but their contributions to science and the field of paleontology were massive, and provided substantial material for further work—both scientists left behind many unopened boxes of fossils after their deaths. The efforts of the two men led to over 136 new species of dinosaurs being discovered and described. The products of the Bone Wars resulted in an increase in knowledge of prehistoric life, and sparked the public's interest in dinosaurs, leading to continued fossil excavation in North America in the decades to follow. Several historical books and fictional adaptations have been published about this period of intense fossil-hunting activity.


At one time, Cope and Marsh were amicable. They met in Berlin in 1864 and spent several days together. They even named species after each other. Over time their relations soured due in part to their strong personalities. Cope was known to be pugnacious and possessed a quick temper; Marsh was slower, more methodical, and introverted. Both were quarrelsome and distrustful. Their differences also extended into the scientific realm as Cope was a firm supporter of Neo-Lamarckism while Marsh supported Charles Darwin's theory of evolution by natural selection. Even at the best of times both men were inclined to look down on each other subtly. As one observer put it, "The patrician Edward may have considered Marsh not quite a gentleman. The academic Othniel probably regarded Cope as not quite a professional."

Cope and Marsh came from very different backgrounds. Cope was born into a wealthy and influential Quaker family based in Philadelphia. Although his father wanted his son to work as a farmer, Cope distinguished himself as a naturalist. In 1864, already a member of the Academy of Natural Sciences, Cope became a professor of zoology at Haverford College and joined Ferdinand Hayden on his expeditions west. In contrast, Marsh would have grown up poor, the son of a struggling family in Lockport, New York, had it not been for the benefaction of his uncle, philanthropist George Peabody. Marsh persuaded his uncle to build the Peabody Museum of Natural History, placing Marsh as head of the museum. Combined with the inheritance he received from Peabody upon his death in 1869, Marsh was financially comfortable (although, partly because of Peabody's stern views on marriage, Marsh would remain a lifelong bachelor).

On one occasion, the two scientists had gone on a fossil-collecting expedition to Cope's marl pits in New Jersey, where William Parker Foulke had discovered the holotype specimen of Hadrosaurus foulkii, described by the paleontologist Joseph Leidy (under whom Cope had studied comparative anatomy); this was one of the first American dinosaur finds, and the pits were still rich with fossils. Though the two parted amicably, Marsh secretly bribed the pit operators to divert future fossil finds to him, instead of Cope. The two began attacking each other in papers and publications, and their personal relations deteriorated. Marsh humiliated Cope by pointing out his reconstruction of the plesiosaur Elasmosaurus was flawed, with the head placed where the tail should have been (or so he claimed, 20 years later; it was Leidy who published the correction shortly afterwards). Cope, in turn, began collecting in what Marsh considered his private bone-hunting turf in Kansas and in Wyoming, further damaging their relationship

Personal Disputes

While Cope and Marsh dueled for fossils in the American West, they also tried their best to ruin each other's professional credibility. Humiliated by his error in reconstructing the plesiosaur Elasmosaurus, Cope tried to cover up his mistake by purchasing every copy he could find of the journal it was published in. Marsh, meanwhile, made sure to publicize the story. Cope's own rapid and prodigious output of scientific papers meant that Marsh had no difficulty in finding occasional errors to lambast Cope with. Marsh himself was not infallible; he put the wrong skull on a skeleton of Apatosaurus and declared it a new genus, Brontosaurus.

By the late 1880s, public attention to the fighting between Cope and Marsh faded, drawn to international stories rather than the "Wild West". Thanks to John Wesley Powell, head of the U.S. Geological Survey, and Marsh's contacts with the rich and powerful in Washington, Marsh was placed at the head of the consolidated government survey and was happy to be out of the sensationalist spotlight. Cope was much less well-off, having spent most of his money purchasing The American Naturalist, and had a hard time finding employment thanks to Marsh's allies in higher education and Cope's own temperament. Cope began investing in gold and silver prospects in the West, and braved malarial mosquitos and harsh weather to search for fossils himself. Due to setbacks in mining and a lack of support from the federal government, Cope's financial situation steadily deteriorated, to the point that his fossil collection was his only significant asset. Marsh, meanwhile, alienated even his loyal assistants, including Williston, with his refusal to share his conclusions drawn from their findings, and his continually lax and infrequent payment schedule.

Cope's chance to exploit Marsh's vulnerabilities came in 1884, when Congress began to investigate the proceedings of the consolidated geological survey. Cope had become friends with Henry Fairfield Osborn, then a professor of anatomy at Princeton University. Osborn was like Marsh in many ways, slow and methodical, but would prove a damaging influence on Marsh. Cope searched for disgruntled workers who would speak out against Powell and the Survey. For the moment, Powell and Marsh were able to successfully refute Cope's charges, and his allegations did not reach the mainstream press. Osborn seemed reluctant to step up his campaign against Marsh, so Cope turned to another ally he had mentioned to Osborn—a "newspaper man from New York" named William Hosea Ballou. Despite setbacks in trying to oust Marsh from his presidency of the National Academy of Sciences, Cope received a tremendous financial boost after the University of Pennsylvania offered him a teaching job.

Thursday, August 17, 2017

The Zen Koan

A kōan is a story, dialogue, question, or statement, which is used in Zen practice to provoke the "great doubt" and test a student's progress in Zen practice.

Doctrinal Background

The popular western understanding sees kōan as referring to an unanswerable question or a meaningless statement. However, in Zen practice, a kōan is not meaningless, and not a riddle or a puzzle. Teachers do expect students to present an appropriate response when asked about a kōan.

Koans are also understood as pointers to an unmediated "Pure Consciousness", devoid of cognitive activity. Victor Hori criticizes this understanding:

[A] pure consciousness without concepts, if there could be such a thing, would be a booming, buzzing confusion, a sensory field of flashes of light, unidentifiable sounds, ambiguous shapes, color patches without significance. This is not the consciousness of the enlightened Zen master.

According to Hori, a central theme of many koans is the 'identity of opposites':

[K]oan after koan explores the theme of nonduality. Hakuin's well-known koan, "Two hands clap and there is a sound, what is the sound of one hand?" is clearly about two and one. The koan asks, you know what duality is, now what is nonduality? In "What is your original face before your mother and father were born?" the phrase "father and mother" alludes to duality. This is obvious to someone versed in the Chinese tradition, where so much philosophical thought is presented in the imagery of paired opposites. The phrase "your original face" alludes to the original nonduality.

Comparable statements are: "Look at the flower and the flower also looks"; "Guest and host interchange

Koan Practice

Study of kōan literature is common to all schools of Zen, though with varying emphases and curriculae. The Rinzai-school uses extensive koan-curricula, checking questions, and jakogo ("capping phrases", quotations from Chinese poetry) in its use of koans. The Sanbo Kyodan, and its western derivates of Taizan Maezumi and the White Plum Asanga, also use koan-curricula, but have omitted the use of capping phrases. In Chinese Chán and Korean Seon, the emphasis is on Hua Tou, the study of one koan throughout one's lifetime. In Japanese Soto-Zen, the use of koans has been abandoned since the late eighteenth and nineteenth century.

Hua-tou or breakthrough-koan

In the Rinzai-school, the Sanbo Kyodan, and the White Plum Asanga, koan practice starts with the assignment of a hosshi or "break-through koan", usually the mu-koan or "the sound of one hand clapping". In Chinese Chán and Korean Seon, various koan can be used for the hua-tou practice.

Students are instructed to concentrate on the "word-head", like the phrase "mu". In the Wumenguan (Mumonkan), public case #1 ("Zhaozhou's Dog"), Wumen (Mumon) wrote:

... concentrate yourself into this 'Wú' ... making your whole body one great inquiry. Day and night work intently at it. Do not attempt nihilistic or dualistic interpretations."

Arousing this great inquiry or "Great Doubt" is an essential element of kōan practice. It builds up "strong internal pressure (gidan), never stopping knocking from within at the door of [the] mind, demanding to be resolved". To illustrate the enormous concentration required in kōan meditation, Zen Master Wumen commented,

It is like swallowing a red-hot iron ball. You try to vomit it out, but you can't.

Analysing the koan for its literal meaning won't lead to insight, though understanding the context from which koans emerged can make them more intelligible. For example, when a monk asked Zhaozhou (Joshu) "does a dog have Buddha-nature or not?", the monk was referring to the understanding of the teachings on Buddha-nature, which were understood in the Chinese context of absolute and relative reality.


The continuous pondering of the break-through koan (shokan) or Hua Tou, "word head", leads to kensho, an initial insight into "seeing the (Buddha-)nature.

The aim of the break-through koan is to see the "nonduality of subject and object":

The monk himself in his seeking is the koan. Realization of this is the insight; the response to the koan [...] Subject and object - this is two hands clapping. When the monk realizes that the koan is not merely an object of consciousness but is also he himself as the activity of seeking an answer to the koan, then subject and object are no longer separate and distinct [...] This is one hand clapping.

Various accounts can be found which describe this "becoming one" and the resulting breakthrough:

I was dead tired. That evening when I tried to settle down to sleep, the instant I laid my head on the pillow, I saw: "Ah, this outbreath is Mu!" Then: the in-breath too is Mu!" Next breath, too: Mu! Next breath: Mu, Mu! "Mu, a whole sequence of Mu! Croak, croak; meow, meow - these too are Mu! The bedding, the wall, the column, the sliding-door - these too are Mu! This, that and everything is Mu! Ha ha! Ha ha ha ha Ha! that roshi is a rascal! He's always tricking people with his 'Mu, Mu, Mu'!...

But the use of the mu-koan has also been criticised. According to AMA Samy, the main aim is merely to "'become one' with the koan". Showing to have 'become one' with the first koan is enough to pass the first koan. According to Samy, this is not equal to prajna:

The one-pointed, non-intellectual concentration on the hua-t’ou (or Mu) is a pressure-cooker tactics, a reduction to a technique which can produce some psychic experiences. These methods and techniques are forced efforts which can even run on auto-pilot. They can produce experiences but not prajana wisdom. Some speak of ‘investigating’ the hua-t’ou, but it is rather a matter of concentration, which sometimes can provide insights, yet no more than that.

Testing insight - or learning responses

Sassho – Checking questions

Teachers may probe students about their kōan practice using sassho, "checking questions" to validate their satori (understanding) or kensho (seeing the nature). For the mu-koan and the clapping hand-koan there are twenty to a hundred checking questions, depending on the teaching lineage. The checking questions serve to deepen the insight of the student, but also to test his or her understanding.

Those checking questions, and their answers, are part of a standardised set of questions and answers. Students are learning a "ritual performance", learning how to behave and response in specific ways, learning "clever repartees, ritualized language and gestures and be submissive to the master’s diktat and arbitration."

Jakugo – Capping phrases

In the Rinzai-school, passing a koan and the checking questions has to be supplemented by jakugo, "capping phrases", citations of Chinese poetry to demonstrate the insight. Students can use collections of those citations, instead of composing poetry themselves.[

Afterword by the Blog Author

In occidental thought and logical argumentation, the koan is sometimes regarded as an insult used to derail honest intellectual inquiry.  If a student asks an honest question and receives a koan as the response by the instructor, this technique is a deal breaker that terminates honest inquiry and discussion.  The westerner would only use this approach to introduce an as yet unproven (though also not disproven) conjecture.  Thus the koan provides an example of a sharp distinction between occidental and oriental epistemology. 

Wednesday, August 16, 2017

Physics and Math Genius Poincare

Jules Henri Poincaré (29 April 1854 – 17 July 1912) was a French mathematician, theoretical physicist, engineer, and philosopher of science. He is often described as a polymath, and in mathematics as The Last Universalist by Eric Temple Bell, since he excelled in all fields of the discipline as it existed during his lifetime.


As a mathematician and physicist, he made many original fundamental contributions to pure and applied mathematics, mathematical physics, and celestial mechanics. He was responsible for formulating the Poincaré conjecture, which was one of the most famous unsolved problems in mathematics until it was solved in 2002–2003 by Grigori Perelman. In his research on the three-body problem, Poincaré became the first person to discover a chaotic deterministic system which laid the foundations of modern chaos theory. He is also considered to be one of the founders of the field of topology.

Poincaré made clear the importance of paying attention to the invariance of laws of physics under different transformations, and was the first to present the Lorentz transformations in their modern symmetrical form. Poincaré discovered the remaining relativistic velocity transformations and recorded them in a letter to Dutch physicist Hendrik Lorentz (1853–1928) in 1905. Thus he obtained perfect invariance of all of Maxwell's equations, an important step in the formulation of the theory of special relativity. In 1905, Poincaré first proposed gravitational waves (ondes gravifiques) emanating from a body and propagating at the speed of light as being required by the Lorentz transformations.

The Poincaré group used in physics and mathematics was named after him.



  • Oscar II, King of Sweden's mathematical competition (1887)
  • Foreign member of the Royal Netherlands Academy of Arts and Sciences (1897)
  • American Philosophical Society 1899
  • Gold Medal of the Royal Astronomical Society of London (1900)
  • Bolyai Prize in 1905
  • Matteucci Medal 1905
  • French Academy of Sciences 1906
  • Académie française 1909
  • Bruce Medal (1911)

Named after him

  • Institut Henri Poincaré (mathematics and theoretical physics center)
  • Poincaré Prize (Mathematical Physics International Prize)
  • Annales Henri Poincaré (Scientific Journal)
  • Poincaré Seminar (nicknamed "Bourbaphy")
  • The crater Poincaré on the Moon
  • Asteroid 2021 Poincaré

Henri Poincaré did not receive the Nobel Prize in Physics, but he had influential advocates like Henri Becquerel or committee member Gösta Mittag-Leffler. The nomination archive reveals that Poincaré received a total of 51 nominations between 1904 and 1912, the year of his death. Of the 58 nominations for the 1910 Nobel Prize, 34 named Poincaré.  Nominators included Nobel laureates Hendrik Lorentz and Pieter Zeeman (both of 1902), Marie Curie (of 1903), Albert Michelson (of 1907), Gabriel Lippmann (of 1908) and Guglielmo Marconi (of 1909).

The fact that renowned theoretical physicists like Poincaré, Boltzmann or Gibbs were not awarded the Nobel Prize is seen as evidence that the Nobel committee had more regard for experimentation than theory. In Poincaré's case, several of those who nominated him pointed out that the greatest problem was to name a specific discovery, invention, or technique.

Tuesday, August 15, 2017

Detecting Cancer with Sugar

Scientists from the University of Würzburg have synthesized a complex sugar molecule which specifically binds to the tumor protein Galectin-1. This could help to recognize tumors at an early stage and to combat them in a targeted manner.

University of Wurzburg, August 14, 2017 -- Galectins are a family of proteins that have become a promising source of cancer research in recent years. A representative thereof is galectin-1. It sits on the surface of all human cells; on tumor cells, however, it occurs in enormous quantities. This makes it an interesting target for diagnostics and therapy.

"Among other things, it is known that galectin-1 hides the tumor cells from the immune system," explains Professor Jürgen Seibel of the Institute of Organic Chemistry at the Julius-Maximilians-Universität (JMU) Würzburg in Bavaria, Germany. Recent studies have shown that when Galectin-1 is blocked, the immune system can recognize the tumor and attack it with T cells.

Sugar molecule with docking station

No wonder, therefore, that galectin-1 has become a major focus of research. Seibel and his colleague Dr. Clemens Grimm is interested in a very specific section of this protein, the so-called carbohydrate recognition domain. They have now designed a complex sugar molecule that fits perfectly into this domain, as the scientists report in journal "ChemBioChem".

"We have equipped the sugar molecule with a docking site, for example, to connect it with a fluorescent dye or an drug," says Seibel. In addition, the scientists have described the binding of their molecule to galectin-1 with high-resolution X-ray structure analyzes.

"Our findings can serve the development of high-affinity ligands of the protein Galectin-1 and thus of new drugs," said Clemens Grimm.

Quick test for Galectin-1 in progress

Now the JMU scientists are working on a rapid test for the detection of galectin-1. It is designed to enable early detection of tumors such as neuroblastoma. For the future, Seibel's team would like to expand the sugar molecules into a kind of shuttle system that allows pharmaceutical agents to be transported directly to the tumors.

Monday, August 14, 2017

Is the Internet Growing Dark?

The Darkening Web is a new book by Alexander Klimburg about the under-reported fight over the control and power of the internet and cyberspace.  Below are some remarks and reviews available on

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"A chilling but well-informed and readable tour of cyber interdependence. Anyone interested in our growing global vulnerabilities should read this book.”
—Joseph S. Nye, Jr., author of The Future of Power

No single invention of the last half century has changed the way we live now as much as the Internet. Alexander Klimburg was a member of the generation for whom it was a utopian ideal turned reality: a place where ideas, information, and knowledge could be shared and new freedoms found and enjoyed. Two decades later, the future isn’t so bright any more: increasingly, the Internet is used as a weapon and a means of domination by states eager to exploit or curtail global connectivity in order to further their national interests.

Klimburg is a leading voice in the conversation on the implications of this dangerous shift, and in The Darkening Web, he explains why we underestimate the consequences of states’ ambitions to project power in cyberspace at our peril: Not only have hacking and cyber operations fundamentally changed the nature of political conflict—ensnaring states in a struggle to maintain a precarious peace that could rapidly collapse into all-out war—but the rise of covert influencing and information warfare has enabled these same global powers to create and disseminate their own distorted versions of reality in which anything is possible. At stake are not only our personal data or the electrical grid, but the Internet as we know it today—and with it the very existence of open and democratic societies.

Blending anecdote with argument, Klimburg brings us face-to-face with the range of threats the struggle for cyberspace presents, from an apocalyptic scenario of debilitated civilian infrastructure to a 1984-like erosion of privacy and freedom of expression. Focusing on different approaches to cyber-conflict in the US, Russia and China, he reveals the extent to which the battle for control of the Internet is as complex and perilous as the one surrounding nuclear weapons during the Cold War—and quite possibly as dangerous for humanity as a whole.

Authoritative, thought-provoking, and compellingly argued, The Darkening Web makes clear that the debate about the different aspirations for cyberspace is nothing short of a war over our global values.

Editorial Reviews

The Darkening Web provides a sweeping yet nuanced overview of how we got to where we are online, with ample backstory… A thoughtful framework for assessing developments in this fast-moving area…Ultimately, Klimburg concludes, the battle for a free Internet ‘is nothing less than the struggle for the heart of modern democratic society.’”—Nature 

“Exhaustively researched. . . . A complex, fascinating book. . . . Indispensable reading for anyone keen to understand what lies ahead as cyberspace displaces conventional battlefields as the preferred venue for resolving conflict.”—The Toronto Star

“A dark but riveting account of how competition between nations threatens the future of the Internet. Klimburg provides a broad overview of the technical and political underpinnings of the Internet and reveals how many of them are being eroded by short-sightedness and national pride. A must-read.”—Jeff Moss, founder of Black Hat and DEF CON conferences

“A compelling and authoritative book that will shape the conversation about the intersection of the Internet and foreign policy.”—Bruce Schneier, author of Data and Goliath

“At a time of rising focus on threats to the internet, Alexander Klimburg introduces much needed clarity and precision into such concepts as cyber war and information security. This book is indispensable—not only for national security officials formulating policies on cyber conflict, cyber crime and cyber governance, but for any reader seeking a strong grounding in this critically important material and what it means for our global future.”—Michael Chertoff, former U.S. Secretary of Homeland Security

“Alexander Klimburg provides a chilling but well-informed and readable tour of cyber interdependence. Anyone interested in our growing global vulnerabilities should read this book.”—Joseph S. Nye, Jr., University Distinguished Service Professor at Harvard University and author of The Future of Power

“Klimburg is exceedingly qualified to write about cyberspace as a new field of war. . . . The dark side of cyberspace is a daunting subject, but Klimburg’s narrative is very accessible, and frankly, this is all far too important to ignore.”—Booklist 

“A very frightening book. . . . Reading it is well worth the effort. Recommended for anyone interested in international affairs.”Library Journal

“An excellent primer on cyberwarfare. . . . A chilling portrait of the emergence of cyberspace as a domain for political conflict.”—Publishers Weekly

“Klimburg delivers an urgent warning that civil libertarians and cybernauts alike will want to heed.” – Kirkus Reviews

About the Author

Alexander Klimburg is a program director at The Hague Centre for Strategic Studies, a nonresident senior fellow at the Atlantic Council, and an associate and former fellow at the Belfer Center of the Harvard Kennedy School. He has acted as an advisor to a number of governments and international organizations on cybersecurity strategy and internet governance, and has participated in various national, international, NATO and EU policy groups. He splits his time between Boston, Vienna and The Hague.

Sunday, August 13, 2017

A Summary on Populism

Populism is a mode of political communication that is centred around contrasts between the "common man" or "the people" and a real or imagined group of "privileged elites", traditionally scapegoating or making a folk devil of the latter. Populists can fall anywhere on the traditional left–right political spectrum of politics, and can often be characterised as centrist where populists portray both bourgeois capitalists and socialist organizers as unfairly dominating the political sphere.

Political parties and politicians often use the terms populist and populism as pejoratives against their opponents. Such a view sees populism as demagogy, merely appearing to empathize with the public through rhetoric or unrealistic proposals in order to increase appeal across the political spectrum.

Populism is most common in democratic nations. Political scientist Cas Mudde wrote that "Many observers have noted that populism is inherent to representative democracy; after all, do populists not juxtapose 'the pure people' against 'the corrupt elite'?"

Authoritarianism and Populism

Scholars have argued that populist elements have sometimes appeared in authoritarian movements. Conspiracist scapegoating employed by various populist movements can create "a seedbed for fascism."

National Socialist populism interacted with and facilitated fascism in interwar Germany. In this case, distressed middle–class populists mobilized their anger against the government and big business during the pre-Nazi Weimar period. The Nazis "parasitized the forms and themes of the populists and moved their constituencies far to the right through ideological appeals involving demagoguery, scapegoating, and conspiracism."

According to Fritzsche:

The Nazis expressed the populist yearnings of middle–class constituents and at the same time advocated a strong and resolutely anti-Marxist mobilization...Against "unnaturally" divisive parties and querulous organized interest groups, National Socialists cast themselves as representatives of the commonwealth, of an allegedly betrayed and neglected German public...Breaking social barriers of status and caste, and celebrating at least rhetorically the populist ideal of the people's community...

At the turn of the 21st century, the pink tide spreading over Latin America was "prone to populism and authoritarianism". Steven Levitsky and James Loxton, as well as Raúl Madrid, stated that Venezuelan president Hugo Chávez and his regional allies used populism to achieve their dominance and later established authoritarian regimes when they were empowered. Such actions, Weyland argues, proves that "Populism, understood as a strategy for winning and exerting state power, inherently stands in tension with democracy and the value that it places upon pluralism, open debate, and fair competition".

In a The New York Times piece following the 2017 Venezuelan constitutional crisis, it was stated that:

Populism is a path that, at its outset, can look and feel democratic. But, followed to its logical conclusion, it can lead to democratic backsliding or even outright authoritarianism.

Populism in the U.S.

There have been several versions of a populist movement in the United States. The terminology was inspired by the Populist Party of the 1890s. This was the party of the early 1890s which Midwestern and Southern farmers and some labor unions denounced a system whereby "the fruits of the toil of millions are boldly stolen to build up colossal fortunes for a few." The term "populist" re-emerged in the 1950s when historian Richard Hofstadter and sociologist Daniel Bell compared the anti-elitism of the 1890s Populists with that of Joseph McCarthy. Although not all academics accepted the comparison between the left-wing, anti-big business Populists and the right-wing, anti-communist McCarthyites, the term "populist" nonetheless came to be applied to both left-wing and right-wing groups that blamed elites for the problems facing the country.

Other early populist political parties in the United States included the Greenback Party, the Progressive Party of 1912 led by Theodore Roosevelt, the Progressive Party of 1924 led by Robert M. La Follette, Sr., and the Share Our Wealth movement of Huey Long in 1933–1935.

Lynn Frazier, three-term Governor of North Dakota, led the Nonpartisan League in a right-wing populist movement that gained control of North Dakota's lower house and won 79% of the popular vote in North Dakota's gubernatorial election of 1916. Campaigning as Republicans against Democrats who were supported by intellectuals and liberal reformers espousing collectivist and corporate farming, the NPL gained a large share of the rural and agrarian vote. There have also been left-wing leaders of populist movements such as Free Silver advocate William Jennings Bryan and consumer protection advocate Ralph Nader. They campaigned against the power of large corporations such as national banks and auto companies, as presidential candidates for the Democratic Party and Green Party, respectively.

Populism remains a force in modern US politics. The media have identified numerous populist candidates in recent years. The third-party presidential campaigns of billionaire Ross Perot in 1992 and 1996 have been perceived as populist. The 1996, 2000, 2004, and the 2008 presidential campaigns of Ralph Nader had a strong populist cast. The 2004 and 2008 Democratic presidential candidate John Edwards has been described by many (and by himself) as a "one economic community, one commonwealth" populist.

From its beginnings in early 2009, the Tea Party movement has used populist rhetoric, particularly in areas and states where Democrats are in power. Boyer et al. states:

The Tea Party's name, large outdoor rallies, populist rhetoric, and use of patriotic symbols (notably, the "Don't Tread On Me" Gadsen Flag, which emerged as the movement's standard) tapped into the historical legacy of the Antifederalist movement of the 1780s.

In a recent example of populist movements, participants in the Occupy movement chose the slogan "We are the 99%". The Occupy leadership used the phrase "the 1%" to refer to the 1% of Americans who are most wealthy. The Occupy movement believed that the 1% was creating economic instability and undermining the social safety nets implemented during the New Deal. Political science professors Joe Lowndes and Dorian Warren were among those to pose the question, "Is Occupy Wall Street a Populist Movement?" They both concluded that it was the "first major populist movement on the U.S left since the 1930s."

The 2016 presidential election saw a wave of populist sentiment in the campaigns of Bernie Sanders (as a self-described "democratic socialist") and Donald Trump, with both candidates running on anti-establishment platforms in the Democratic and Republican parties, respectively. Both campaigns appealed to criticize free trade deals such as the North American Free Trade Agreement and the Trans-Pacific Partnership. Their movements coincided with a similar trend of populism in Europe. Ultimately, Trump was elected President of the United States, defeating the Democratic candidate Hillary Clinton.

Saturday, August 12, 2017

Violent Rally in Charlottesville

The Unite the Right rally was a militant gathering of alt-right, neo-Nazi, white nationalist, and far-right groups in Charlottesville, Virginia, on August 11 and 12, 2017. The participants protested the removal of Confederate monuments and memorials from public spaces, specifically the Robert Edward Lee Sculpture in Emancipation Park.

Speakers scheduled to appear included Tim Treadstone, David Duke, Richard Spencer, Mike Enoch, and League of the South founder Michael Hill. Speakers claimed that Jews are ruining the West, and hailed Donald Trump and Adolf Hitler. During the rally, David Duke stated that the rally intended to fulfill the "promises of Donald Trump." During the rally, a car plowed into a crowd of counter-protesters, killing a woman and injuring 19 others, five critically. At least 19 people were injured in "street brawls" and other violence at the rally. A police helicopter monitoring the response to the rally violence crashed, killing the two troopers on board.

Witnesses described the violence as having originated from white nationalists.


On May 15, 2017, a similar protest occurred against the city's plans to remove a statue of Confederate General Robert E. Lee from a downtown park, which was led by Richard Spencer. The event involved protesters holding torches near the statue. That same night, a candlelight counter-protest took place which included Black Lives Matter supporters.

The rally occurred when the University of Virginia was between its summer and fall semesters. On August 4, University of Virginia President Teresa Sullivan sent an e-mail to students and faculty, which said, "I urge students and all UVA community members to avoid the August 12 rally and avoid physical confrontation generally. There is a credible risk of violence at this event, and your safety is my foremost concern."

Following the Rally

In an address later in the day following the rally, Virginia Governor Terry McAuliffe, flanked by Charlottesville mayor Michael Signer, and Charlottesville's police chief, directly addressed the "white supremacists and Nazis who came into Charlottesville today," stating: "Our message is plain and simple: Go home. You are not wanted in this great commonwealth. Shame on you. You pretend that you are patriots, but you are anything but patriots. ...We are stronger than you... You will not succeed. There is no place for you here."

Signer said he was disgusted that white supremacists came to his town and faulted President Donald Trump for inflaming racial tensions during his 2016 campaign, stating: "I'm not going to make any bones about it. I place the blame for a lot of what you're seeing in America today right at the doorstep of the White House and the people around the president."

Following the rally, UVA president Teresa A. Sullivan condemned the "senseless violence" at the rally and asked university community members to help protect "The safety and well-being of all members of our community... by staying off the streets tonight as our public safety officials work to maintain order and offer assistance to those who are in need."

Trump responded by saying: "We all must be united & condemn all that hate stands for. There is no place for this kind of violence in America. Let's come together as one!" He added that he condemned "in the strongest possible terms" what he called an "egregious display of hatred, bigotry and violence on many sides. On many sides." Trump added that "What is vital now is a swift restoration of law and order."

Trump did not specifically denounce white nationalists or white supremacists, and his "many sides" comment was criticized as insufficient by both Democratic and Republican members of Congress. The Congressional Black Caucus stated that that Trump's "false equivalency, dog whistles are sad. White supremacy is to blame." Republican Senators Ted Cruz, Cory Gardner, Chuck Grassley, Orrin Hatch, John McCain, Rob Portman, and Marco Rubio all called upon Trump to specifically condemn white supremacists and neo-Nazis; Gardner stated: "Mr. President – we must call evil by its name. These were white supremacists and this was domestic terrorism." Virginia Attorney General Mark Herring stated: "The violence, chaos, and apparent loss of life in Charlottesville is not the fault of 'many sides.' It is racists and white supremacists."

Former Ku Klux Klan Klan leader David Duke wrote in response that Trump should "take a good look in the mirror & remember it was White Americans who put you in the presidency, not radical leftists." The website Daily Stormer, which promoted the rally, praised Trump's response, writing "He didn't attack us. He just said the nation should come together. Nothing specific against us.”


Friday, August 11, 2017

Most Boring Movie Ever?

Baa Baa Land is a 2017 slow cinema film produced by Calm that features no human actors, dialogue or narrative. Written and produced by Peter Freedman, and shot and edited by Garth Thomas, the American-financed, British-made film will premiere at the Prince Charles Cinema in London's West End during September 2017.

                                                                       movie poster

The film is an example of "slow cinema", an art cinema technique that focuses on long takes, minimalism, and often very little to no narrative or dialogue. The film has no plot and is described as the "dullest movie ever made" by producer Peter Freedman. It features "hundreds" of sheep simply standing in fields with very little additional action; each shot lasts between 30 minutes to over 60 minutes.

Baa Baa Land's length of eight hours has led some to call it the nineteenth longest film of all time, the same length as Andy Warhol's 1967 film The Imitation of Christ and five minutes shorter than Empire. Executive producer Michael Acton Smith does not expect Baa Baa Land to "break box-office records", though expects that there may be a significant niche audience for the title. It is intended and expected to put people to sleep, and has been described as "the ultimate insomnia cure.”


Baa Baa Land was produced by the founders of Calm, an app designed to facilitate meditation and relaxation. It was filmed at the Layer Marney lamb and sheep farm near Tiptree in Essex, United Kingdom. The idea for a film where the only actors are sheep was conceived by producer Peter Freedman, and the film was directed, shot and edited by art film director Garth Thomas on a "modest budget".


Thursday, August 10, 2017

Models of Galactic Wind

Galactic Winds Push Researchers to
Probe Galaxies at Unprecedented Scale
Supercomputers Required for such Massive Models
By Jonathan Hines, August 8, 2017

Oak Ridge National Laboratory -- When astronomers peer into the universe, what they see often exceeds the limits of human understanding. Such is the case with low-mass galaxies—galaxies a fraction of the size of our own Milky Way.
These small, faint systems made up of millions or billions of stars, dust, and gas constitute the most common type of galaxy observed in the universe. But according to astrophysicists’ most advanced models, low-mass galaxies should contain many more stars than they appear to contain.

A leading theory for this discrepancy hinges on the fountain-like outflows of gas observed exiting some galaxies. These outflows are driven by the life and death of stars, specifically stellar winds and supernova explosions, which collectively give rise to a phenomenon known as “galactic wind.” As star activity expels gas into intergalactic space, galaxies lose precious raw material to make new stars. The physics and forces at play during this process, however, remain something of a mystery.

To better understand how galactic wind affects star formation in galaxies, a two-person team led by the University of California, Santa Cruz, turned to high-performance computing at the Oak Ridge Leadership Computing Facility (OLCF), a US Department of Energy (DOE) Office of Science User Facility located at DOE’s Oak Ridge National Laboratory (ORNL). Specifically, UC Santa Cruz astrophysicist Brant Robertson and University of Arizona graduate student Evan Schneider (now a Hubble Fellow at Princeton University), scaled up their Cholla hydrodynamics code on the OLCF’s Cray XK7 Titan supercomputer to create highly detailed simulations of galactic wind.

“The process of generating galactic winds is something that requires exquisite resolution over a large volume to understand—much better resolution than other cosmological simulations that model populations of galaxies,” Robertson said. “This is something you really need a machine like Titan to do.”
After earning an allocation on Titan through DOE’s INCITE program, Robertson and Schneider started small, simulating a hot, supernova-driven wind colliding with a cool cloud of gas across 300 light years of space. (A light year equals the distance light travels in 1 year.) The results allowed the team to rule out a potential mechanism for galactic wind.

Now the team is setting its sights higher, aiming to generate nearly a trillion-cell simulation of an entire galaxy, which would be the largest simulation of a galaxy ever. Beyond breaking records, Robertson and Schneider are striving to uncover new details about galactic wind and the forces that regulate galaxies, insights that could improve our understanding of low-mass galaxies, dark matter, and the evolution of the universe.
A density projection derived from a preliminary full-galaxy simulation of galactic winds being driven by a hot outflow in a starburst galaxy. The top panel looks “down-the-barrel” of the outflow, while the bottom panel shows the disk galaxy at the edge.
Credit: Evan Schneider, Princeton University

Simulating cold clouds

About 12 million light years from Earth resides one of the Milky Way’s closest neighbors, a disk galaxy called Messier 82 (M82). Smaller than the Milky Way, M82’s cigar shape underscores a volatile personality. The galaxy produces new stars about five times faster than our own galaxy’s rate of star production. This star-making frenzy gives rise to galactic wind that pushes out more gas than the system keeps in, leading astronomers to estimate that M82 will run out of fuel in just 8 million years.
Analyzing images from NASA’s Hubble Space Telescope, scientists can observe this slow-developing exodus of gas and dust. Data gathered from such observations can help Robertson and Schneider gauge if they are on the right track when simulating galactic wind.

“With galaxies like M82, you see a lot of cold material at large radius that’s flowing out very fast. We wanted to see, if you took a realistic cloud of cold gas and hit it with a hot, fast-flowing, supernova-driven outflow, if you could accelerate that cold material to velocities like what are observed,” Robertson said.
Answering this question in high resolution required an efficient code that could solve the problem based on well-known physics, such as the motion of liquids. Robertson and Schneider developed Cholla to carry out hydrodynamics calculations entirely on GPUs, highly parallelized accelerators that excel at simple number crunching, thus achieving high-resolution results.

In Titan, a 27-petaflop system containing more than 18,000 GPUs, Cholla found its match. After testing the code on a GPU cluster at the University of Arizona, Robertson and Schneider benchmarked Cholla under two small OLCF Director’s Discretionary awards before letting the code loose under INCITE. In test runs, the code has maintained scaling across more than 16,000 GPUs.
“We can use all of Titan,” Robertson said, “which is kind of amazing because the vast majority of the power of that system is in GPUs.”

The pairing of code and computer gave Robertson and Schneider the tools needed to produce high-fidelity simulations of gas clouds measuring more than 15 light years in diameter. Furthermore, the team can zoom in on parts of the simulation to study phases and properties of galactic wind in isolation. This capability helped the team to rule out a theory that posited cold clouds close to the galaxy’s center could be pushed out by fast-moving, hot wind from supernovas.
“The answer is it isn’t possible,” Robertson said. “The hot wind actually shreds the clouds and the clouds become sheared and very narrow. They’re like little ribbons that are very difficult to push on.”

Galactic goals

Having proven Cholla’s computing chops, Robertson and Schneider are now planning a full-galaxy simulation about 10 to 20 times larger than their previous effort. Expanding the size of the simulation will allow the team to test an alternate theory for the emergence of galactic wind in disk galaxies like M82. The theory suggests that clouds of cold gas condense out of the hot outflow as they expand and cool.
“That’s something that’s been posited in analytical models but not tested in simulation,” Robertson said. “You have to model the whole galaxy to capture this process because the dynamics of the outflows are such that you need a global simulation of the disk.”

The full-galaxy simulation will likely be composed of hundreds of billions of cells representing more than 30,000 light years of space. To cover this expanse, the team must sacrifice resolution. It can rely on its detailed gas cloud simulations, however, to bridge scales and inform unresolved physics within the larger simulation.
“That’s what’s interesting about doing these simulations at widely different scales,” Robertson said. “We can calibrate after the fact to inform ourselves in how we might be getting the story wrong with the coarser, larger simulation.”

Related Publication:  Evan E. Schneider and Brant E. Robertson, “Hydrodynamical Coupling of Mass and Momentum in Multiphase Galactic Winds.” The Astrophysical Journal 834, no. 2 (2017): 144,