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Posts Tagged ‘Alan Turing

“Nothing happens until something moves”*…

 

Universe

 

What determines our fate? To the Stoic Greek philosophers, fate is the external product of divine will, ‘the thread of your destiny’. To transcendentalists such as Henry David Thoreau, it is an inward matter of self-determination, of ‘what a man thinks of himself’. To modern cosmologists, fate is something else entirely: a sweeping, impersonal physical process that can be boiled down into a single, momentous number known as the Hubble Constant.

The Hubble Constant can be defined simply as the rate at which the Universe is expanding, a measure of how quickly the space between galaxies is stretching apart. The slightest interpretation exposes a web of complexity encased within that seeming simplicity, however. Extrapolating the expansion process backward implies that all the galaxies we can observe originated together at some point in the past – emerging from a Big Bang – and that the Universe has a finite age. Extrapolating forward presents two starkly opposed futures, either an endless era of expansion and dissipation or an eventual turnabout that will wipe out the current order and begin the process anew.

That’s a lot of emotional and intellectual weight resting on one small number…

How scientists pinned a single number on all of existence: “Fate of the Universe.”

[Readers might remember that the Big Bang wasn’t always an accepted paradigm— and that on-going research continues to surface challenges.]

* Albert Einstein

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As we center ourselves, we might spare a thought for Kurt Friedrich Gödel; he died on this date in 1978.  A  logician, mathematician, and philosopher, he is considered (along with Aristotle, Alfred Tarski— whose birthday this also is– and Gottlob Frege) to be one of the most important logicians in history.  Gödel had an immense impact upon scientific and philosophical thinking in the 20th century.  He is, perhaps, best remembered for his Incompleteness Theorems, which led to (among other important results) Alan Turing’s insights into computational theory.

Kurt Gödel’s achievement in modern logic is singular and monumental – indeed it is more than a monument, it is a landmark which will remain visible far in space and time. … The subject of logic has certainly completely changed its nature and possibilities with Gödel’s achievement.                  — John von Neumann

kurt_gödel source

 

“Encryption works”*…

 

SIGSALY-1943

A SIGSALY terminal in 1943

 

During World War II, a British-American team that included Claude Shannon and Alan Turing created the first digitally scrambled, wireless phone known as SIGSALY…

Declassified only in 1976, it was a joint effort of Bell Labs and Britain’s Government Code and Cipher School at Bletchley Park, north of London. It had a scientific pedigree rivaling that of the Manhattan Project, for the British-American team included not only Shannon but also Alan Turing. They were building a system known as SIGSALY. That was not an acronym, just a random string of letters to confuse the Germans, should they learn of it.

SIGSALY was the first digitally scrambled, wireless phone. Each SIGSALY terminal was a room-sized, 55-ton computer with an iso­lation booth for the user and an air-conditioning system to prevent its banks of vacuum tubes from melting down. It was a way for Al­lied leaders to talk openly, confident that the enemy could not eavesdrop. The Allies built one SIGSALY at the Pentagon for Roo­sevelt and another in the basement of Selfridges department store for Churchill. Others were established for Field Marshal Mont­gomery in North Africa and General MacArthur in Guam. SIGSALY used the only cryptographic system that is known to be uncrackable, the ‘onetime pad.’ In a onetime pad, the ‘key’ used for scrambling and decoding a message is random. Traditionally, this key consisted of a block of random letters or numbers on a pad of paper. The encoded message therefore is random and contains none of the telltale patterns by which cryptograms can be deciphered. The problem with the onetime pad is that the key must be delivered by courier to everyone using the system, a challenge in wartime.

SIGSALY encoded voice rather than a written message. Its key was a vinyl LP record of random ‘white noise.’ ‘Adding’ this noise to Roosevelt’s voice produced an indecipherable hiss. The only way to recover Roosevelt’s words was to ‘subtract’ the same key noise from an identical vinyl record. After pressing the exact number of key records needed, the master was destroyed and the LPs distrib­uted by trusted couriers to the SIGSALY terminals. It was vitally important that the SIGSALY phonographs play at precisely the same speed and in sync. Were one phonograph slightly off, the out­put was abruptly replaced by noise.

Alan Turing cracked the German ‘Enigma’ cipher, allowing the Allies to eavesdrop on the German command’s messages. The point of SIGSALY was to ensure that the Germans couldn’t do the same. Part of Shannon’s job was to prove that the system was indeed im­possible for anyone lacking a key to crack. Without that mathemat­ical assurance, the Allied commanders could not have spoken freely. SIGSALY put several other of Shannon’s ideas into practice for the first time, among them some relating to pulse code modulation. AT&T patented and commercialized many of Shannon’s ideas in the postwar years…

The first wireless “phone”: an excerpt from William Poundstone’s Fortune’s Formula, via Delancey Place.

* Edward Snowden

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As we keep a secret, we might recall that it was on this date in 1909 that Thomas M. Flaherty filed for the first U.S. patent for a “Signal for Crossings”– a traffic signal.  His signal used a large horizontal arrow pivoted on a post, which turned to indicate the right of way direction, and was activated by an electric solenoid operated by a policeman beside the road.

Flaherty’s was the first U.S. application for a traffic signal design, later issued as No. 991,964 on May 9, 1911. But though it was filed first, it was not the first patent actually issued for a traffic signal: Ernest E. Sirrine filed a different design seven months after Flaherty; but his patent was issued earlier, and thus he held the first U.S. patent for a “Street Traffic System.”

 source (and larger version)

 

Written by LW

September 24, 2018 at 1:01 am

Coded references…

Readers will recall the role that Alan Turing and the team at Bletchley Park played in cracking the German Enigma code; some analysts and historians reckon that their work may have shortened World War Two by “not less than two years.”

That code was generated by– and thus cracking it turned on deconstructing and understanding– an Enigma Machine.

source

Understandably, there were few such machines ever built.  And equally understandable, those that survive are extremely expensive collectables.  But readers need fear not!  Now, thanks to our friends at Instructables, one can convert a “Kid’s Game to an Enigma Machine“:

Step-by-step instructions at Instructables.

Readers might also want to visit Cabinet Magazine‘s wonderful “How to Make Anything Signify Anything,” a profile of American code breaker (and code maker) William Friedman:

By the time he retired from the National Security Agency in 1955, Friedman had served for more than thirty years as his government’s chief cryptographer, and—as leader of the team that broke the Japanese PURPLE code in World War II, co-inventor of the US Army’s best cipher machine, author of the papers that gave the field its mathematical foundations, and coiner of the very term cryptanalysis—he had arguably become the most important code-breaker in modern history.

As we reach for our decoder rings, we might recall that it was on this date in 1884 that the states of Alabama, Georgia, Illinois, Indiana, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee and Virginia, with (at least) 50 tornadoes.  Known as “The Enigma Outbreak,” it did an estimated a total of $3–4 million in tornado damage (in 1884 dollars; plus an unknown amount of flood and other damage), destroying over 10,000 structures.

Photo: © D. Burgess / NOAA (source)

 

 

Knowing what’s unknowable…

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We’ve known for quite awhile that there’s a limit to what we can know…  Werner Heisenberg discovered that improved precision regarding, say, an object’s position inevitably degraded the level of certainty of its momentum. Kurt Gödel showed that within any formal mathematical system advanced enough to be useful, it is impossible to use the system to prove every true statement that it contains. And Alan Turing demonstrated that one cannot, in general, determine if a computer algorithm is going to halt.

Now David Wolpert, a physicist working as a computer scientist at NASA Ames, has elaborated on that limit.  As Scientific American reports, Wolpert’s work show’s that

…the universe lies beyond the grasp of any intellect, no matter how powerful, that could exist within the universe. Specifically, during the past two years, he has been refining a proof that no matter what laws of physics govern a universe, there are inevitably facts about the universe that its inhabitants cannot learn by experiment or predict with a computation. Philippe M. Binder, a physicist at the University of Hawaii at Hilo, suggests that the theory implies researchers seeking unified laws cannot hope for anything better than a “theory of almost everything.”

Wolpert proves that in any such system of universes, quantities exist that cannot be ascertained by any inference device inside the system. Thus, the “demon” hypothesized by Pierre-Simon Laplace in the early 1800s (give the demon the exact positions and velocities of every particle in the universe, and it will compute the future state of the universe) is stymied if the demon must be a part of the universe.

Researchers have proved results about the incomputability of specific physical systems before. Wolpert points out that his result is far more general, in that it makes virtually no assumptions about the laws of physics and it requires no limits on the computational power of the inference device other than it must exist within the universe in question. In addition, the result applies not only to predictions of a physical system’s future state but also to observations of a present state and examining a record of a past state.

The theorem’s proof, similar to the results of Gödel’s incompleteness theorem and Turing’s halting problem, relies on a variant of the liar’s paradox—ask Laplace’s demon to predict the following yes/no fact about the future state of the universe: “Will the universe not be one in which your answer to this question is yes?” For the demon, seeking a true yes/no answer is like trying to determine the truth of “This statement is false.” Knowing the exact current state of the entire universe, knowing all the laws governing the universe and having unlimited computing power is no help to the demon in saying truthfully what its answer will be.

Read the full story here.

As we reconcile ourselves to incompleteness, we might console ourselves that it was on this date in 1929 that the Hollywood Sign was officially dedicated in the hills above Hollywood, Los Angeles. It originally read “Hollywoodland ,” but the four last letters were dropped after renovation in 1949.  Recently threatened with demolition for want of maintenance funds, the icon was saved by a donation from Hugh Hefner.

The sign in it’s original form, as seen from Beachwood Canyon (source)

Take two, and I promise that you won’t feel like calling me in the morning…

From the good folks at Pill Talk, a reminder that today’s illicit drugs were yesterday’s featured pharmaceuticals…  From Black Beauties marketed as a weight loss aid to Bayer’s ad for Heroin (“the sedative for coughs”), readers can see them all here.  (And for more on Heroin’s companion in the Bayer catalog, aspirin, see the almanac portion of the post here.)

As we realize that we still have our coughs but don’t really care, we might remark that today is the birthday of not one but two extraordinary mathematicians:  Gottfried Wilhelm Leibniz (1646; variants on his date of birth due to calendar changes), the German  philosopher, scientist, mathematician, diplomat, librarian, lawyer, co-inventor, with Newton, of The Calculus, and “hero” of Neal Stephenson’s Baroque Trilogy…  and  Alan Turing (1912), British mathematician, computer science pioneer (inventor of the Turing Machine, creator of “the Turing Test” and inspiration for “The Turing Prize”) and cryptographer (leading member of the team that cracked the Enigma code during WWII).   Go figure…

Liebnitz (source: UNC)

Turing (source: Univ. of Birmingham)

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