## Posts Tagged ‘**second law of thermodynamics**’

## “Visualization gives you answers to questions you didn’t know you had”*…

Physical representations of data have existed for thousands of years. The List of Physical Visualizations (and the accompanying Gallery) collect illustrative examples, e.g…

5500 BC – Mesopotamian Clay Tokens

The earliest data visualizations were likely physical: built by arranging stones or pebbles, and later, clay tokens. According to an eminent archaeologist (Schmandt-Besserat, 1999):

“Whereas words consist of immaterial sounds, the tokens were concrete, solid, tangible artifacts, which could be handled, arranged and rearranged at will. For instance, the tokens could be ordered in special columns according to types of merchandise, entries and expenditures; donors or recipients. The token system thus encouraged manipulating data by abstracting all possible variables. (Harth 1983. 19) […] No doubt patterning, the presentation of data in a particular configuration, was developed to highlight special items (Luria 1976. 20).”Clay tokens suggest that physical objects were used to externalize information, support visual thinking and enhance cognition way before paper and writing were invented…

There are 370 entries (so far). Browse them at List of Physical Visualizations (@dataphys)

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**As we celebrate the concrete,** we might carefully-calculated birthday greetings to Rolf Landauer; he was born on this date in 1927. A physicist, he made a number important contributions in a range of areas: the thermodynamics of information processing, condensed matter physics, and the conductivity of disordered media.

He is probably best remembered for “Landauer’s Principle,” which described the energy used during a computer’s operation. Whenever the machine is resetting for another computation, bits are flushed from the computer’s memory, and in that electronic operation, a certain amount of energy is lost (a simple logical consequence of the second law of thermodynamics). Thus, when information is erased, there is an inevitable “thermodynamic cost of forgetting,” which governs the development of more energy-efficient computers. The maximum entropy of a bounded physical system is finite– so while most engineers dealt with practical limitations of compacting ever more circuitry onto tiny chips, Landauer considered the theoretical limit: if technology improved indefinitely, how soon will it run into the insuperable barriers set by nature?

A so-called logically reversible computation, in which no information is erased, may in principle be carried out without releasing any heat. This has led to considerable interest in the study of reversible computing. Indeed, without reversible computing, increases in the number of computations per joule of energy dissipated must eventually come to a halt. If Koomey‘s law continues to hold, the limit implied by Landauer’s principle would be reached around the year 2050.

## “No structure, even an artificial one, enjoys the process of entropy. It is the ultimate fate of everything, and everything resists it.”*…

A 19th-century thought experiment that motivates physicists– and information scientists– still…

The universe bets on disorder. Imagine, for example, dropping a thimbleful of red dye into a swimming pool. All of those dye molecules are going to slowly spread throughout the water.

Physicists quantify this tendency to spread by counting the number of possible ways the dye molecules can be arranged. There’s one possible state where the molecules are crowded into the thimble. There’s another where, say, the molecules settle in a tidy clump at the pool’s bottom. But there are uncountable billions of permutations where the molecules spread out in different ways throughout the water. If the universe chooses from all the possible states at random, you can bet that it’s going to end up with one of the vast set of disordered possibilities.

Seen in this way, the inexorable rise in entropy, or disorder, as quantified by the second law of thermodynamics, takes on an almost mathematical certainty. So of course physicists are constantly trying to break it.

One almost did. A thought experiment devised by the Scottish physicist James Clerk Maxwell in 1867 stumped scientists for 115 years. And even after a solution was found, physicists have continued to use “Maxwell’s demon” to push the laws of the universe to their limits…

A thorny thought experiment has been turned into a real experiment—one that physicists use to probe the physics of information: “How Maxwell’s Demon Continues to Startle Scientists,” from Jonathan O’Callaghan (@Astro_Jonny)

* Philip K. Dick

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**As we reconsider the random,** we might send carefully-calculated birthday greetings to Félix Édouard Justin Émile Borel; he was born on this date in 1871. A mathematician (and politician, who served as French Minister of the Navy), he is remembered for his foundational work in measure theory and probability. He published a number of research papers on game theory and was the first to define games of strategy.

But Borel may be best remembered for a thought experiment he introduced in one of his books, proposing that a monkey hitting keys at random on a typewriter keyboard will – with absolute certainty – eventually type every book in France’s Bibliothèque Nationale de France. This is now popularly known as the infinite monkey theorem.

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