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Posts Tagged ‘Physics

“When physicists say ‘we don’t understand what’s going on here,’ they really, really mean it”*…

 

Theoretical physicists and cosmologists deal with the biggest questions, like “Why are we here?” “When did the universe begin?” and “How?” Another questions that bugs them, and likely has bugged you, is “What happened before the Big Bang?”

To be perfectly clear, we can’t definitively answer this question—but we can speculate wildly, with the help of theoretical physicist Sean Carroll from the California Institute of Technology. Carroll gave a talk last month at the bi-annual meeting of the American Astronomical Society in Grapevine, Texas, where he walked through several pre-Bang possibilities that would result in a universe like ours…

Consider the options at: “What Was Our Universe Like Before the Big Bang?

* Theoretical physicist Peter Woit, Columbia University

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As we scrutinize the singularity, we might spare a thought for E. E. Barnard; he died on this date in 1923. Recognized as a gifted observational astronomer, he is probably best known for his discovery of the high proper motion of Barnard’s Star in 1916, which is named in his honor.  But, drawing on his experience as a photographer’s assistant in his adolescence (and building on the work of John William Draper), Barnard also contributed mightily to the development of celestial photography.

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Written by LW

February 6, 2017 at 1:01 am

“For, after all, how do we know that two and two make four?”*…

 

“The teaching of Logic or Dialetics” from a collection of scientific, philosophical and poetic writings, French, 13th century; Bibliotheque Sainte-Genevieve, Paris, France. Photo by Bridgeman

Is logical thinking a way to discover or to debate? The answers from philosophy and mathematics define human knowledge..

The history of logic should be of interest to anyone with aspirations to thinking that is correct, or at least reasonable. This story illustrates different approaches to intellectual enquiry and human cognition more generally. Reflecting on the history of logic forces us to reflect on what it means to be a reasonable cognitive agent, to think properly. Is it to engage in discussions with others? Is it to think for ourselves? Is it to perform calculations?…

The rise and fall and rise of logic: “What is logic?

* George Orwell, 1984

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As we ruminate on reason, we might send enlightened birthday greetings to Benjamin Franklin; he was born on this date in 1706.  One of the Founding Fathers of the United States, Franklin was a renowned polymath: a leading author, printer, political theorist, politician, freemason, postmaster, scientist, inventor, civic activist, statesman, and diplomat. As a scientist, he was a major figure in the American Enlightenment and the history of physics for his discoveries and theories regarding electricity. As an inventor, he is known for the lightning rod, bifocals, and the Franklin stove, among other innovations.  And as a social entrepreneur (who grasped the fact that by united effort a community could have amenities which only the wealthy few can afford for themselves), he helped establish several institutions people now take for granted: a fire company (1736), a library (1731), an insurance company (1752), an academy (the University of Pennsylvania, 1751), a hospital (1751), and the U.S. Postal Service (starting as postmaster of the Colonies in 1753, then becoming U.S. Postmaster during the Revolution).  In most cases these foundations were the first of their kind in North America.

In a Franklin could be merged the virtues of Puritanism without its defects, the illumination of the Enlightenment without its heat.

– Henry Steele Commager

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Written by LW

January 17, 2017 at 1:01 am

“There is nothing more wonderful than a list, instrument of wondrous hypotyposis”*…

 

Da Vinci would carry around a notebook, where he would write and draw anything that moved him. “It is useful,” Leonardo once wrote, to “constantly observe, note, and consider.” Buried in one of these books, dating back to around the 1490s, is a to-do list. And what a to-do list…

Check it out (if not off) at “Leonardo Da Vinci’s To Do List (Circa 1490) Is Much Cooler Than Yours.”

* Umberto Eco, The Name of the Rose

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As we prioritize prioritization, we might spare a thought for Erwin Rudolf Josef Alexander Schrödinger; he died on this date in 1961.  A physicist best remembered in his field for his contributions to the development of quantum mechanics (e.g., the Schrödinger equation), and more generally for his “Schrödinger’s cat thought experiment– a critique of the Copenhagen interpretation of quantum mechanics– he also wrote on philosophy and theoretical biology.  Indeed, both James Watson, and independently, Francis Crick, co-discoverers of the structure of DNA, credited Schrödinger’s What is Life? (1944), with its theoretical description of how the storage of genetic information might work, as an inspiration.

It seems plain and self-evident, yet it needs to be said: the isolated knowledge obtained by a group of specialists in a narrow field has in itself no value whatsoever, but only in its synthesis with all the rest of knowledge and only inasmuch as it really contributes in this synthesis toward answering the demand, “Who are we?”

– from Science and Humanism, 1951

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Written by LW

January 4, 2017 at 1:01 am

“Time is the longest distance between two places”*…

 

In quantum mechanics, time is universal and absolute; its steady ticks dictate the evolving entanglements between particles. But in general relativity (Albert Einstein’s theory of gravity), time is relative and dynamical, a dimension that’s inextricably interwoven with directions x, y and z into a four-dimensional “space-time” fabric. The fabric warps under the weight of matter, causing nearby stuff to fall toward it (this is gravity), and slowing the passage of time relative to clocks far away. Or hop in a rocket and use fuel rather than gravity to accelerate through space, and time dilates; you age less than someone who stayed at home.

Unifying quantum mechanics and general relativity requires reconciling their absolute and relative notions of time. Recently, a promising burst of research on quantum gravity has provided an outline of what the reconciliation might look like — as well as insights on the true nature of time…

The effort to unify quantum mechanics and general relativity means reconciling totally different notions of time; catch up on the state of play at “Quantum Gravity’s Time Problem.”

* Tennessee Williams, The Glass Menagerie

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As we set our watches, we might send carefully-calculated birthday greetings to Gabrielle-Émilie Le Tonnelier de Breteuil, Marquise du Châtelet, the French mathematician and physicist who is probably (if unfairly) better known as Voltaire’s mistress; she was born on this date in 1706.  Fascinated by the work of Newton and Leibniz, she dressed as a man to frequent the cafes where the scientific discussions of the time were held.  Her major work was a translation of Newton’s Principia, for which Voltaire wrote the preface; it was published a decade after her death, and was for many years the only translation of the Principia into French.

Judge me for my own merits, or lack of them, but do not look upon me as a mere appendage to this great general or that great scholar, this star that shines at the court of France or that famed author. I am in my own right a whole person, responsible to myself alone for all that I am, all that I say, all that I do. it may be that there are metaphysicians and philosophers whose learning is greater than mine, although I have not met them. Yet, they are but frail humans, too, and have their faults; so, when I add the sum total of my graces, I confess I am inferior to no one.
– Mme du Châtelet to Frederick the Great of Prussia

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Written by LW

December 17, 2016 at 1:01 am

“Nothing puzzles me more than time and space; and yet nothing troubles me less”…

 

Time crystals– crystals that break both spacial and temporal symmetry– were first predicted by Nobel laureate Frank Wilczek in 2012… and were widely deemed amusing, but impossible (e.g., here).  Now researchers have created time crystals for the first time and say they could one day be used as quantum memories… and might help reconcile Quantum Mechanics with the Theory of Relativity.

Bend your mind at “Physicists Create World’s First Time Crystal,” also here and here (source of the photo above).

* Charles Lamb

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As we ponder Einstein’s insistence that time is an illusion, we might send well-structured birthday greetings to Pierre-Gilles de Gennes; he was born on this date in 1932.  A French physicist, he was awarded the 1991 Nobel Prize for Physics for “discovering that methods developed for studying order phenomena in simple systems can be generalized to more complex forms of matter, in particular to liquid crystals and polymers.”  He described mathematically how, for example, magnetic dipoles, long molecules or molecule chains can under certain conditions form ordered states, and what happens when they pass from an ordered to a disordered state.  Such changes of order occur when, for example, a heated magnet changes from a state in which all the small atomic magnets are lined up in parallel to a disordered state in which the magnets are randomly oriented.  Later, he was concerned with the physical chemistry of adhesion.

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Written by LW

October 24, 2016 at 1:01 am

“in this case there were three determinate states the cat could be in: these being Alive, Dead, and Bloody Furious”*…

 

Of all the bizarre facets of quantum theory, few seem stranger than those captured by Erwin Schrödinger’s famous fable about the cat that is neither alive nor dead. It describes a cat locked inside a windowless box, along with some radioactive material. If the radioactive material happens to decay, then a device releases a hammer, which smashes a vial of poison, which kills the cat. If no radioactivity is detected, the cat lives. Schrödinger dreamt up this gruesome scenario to mock what he considered a ludicrous feature of quantum theory. According to proponents of the theory, before anyone opened the box to check on the cat, the cat was neither alive nor dead; it existed in a strange, quintessentially quantum state of alive-and-dead.

Today, in our LOLcats-saturated world, Schrödinger’s strange little tale is often played for laughs, with a tone more zany than somber. It has also become the standard bearer for a host of quandaries in philosophy and physics. In Schrödinger’s own time, Niels Bohr and Werner Heisenberg proclaimed that hybrid states like the one the cat was supposed to be in were a fundamental feature of nature. Others, like Einstein, insisted that nature must choose: alive or dead, but not both.

Although Schrödinger’s cat flourishes as a meme to this day, discussions tend to overlook one key dimension of the fable: the environment in which Schrödinger conceived it in the first place. It’s no coincidence that, in the face of a looming World War, genocide, and the dismantling of German intellectual life, Schrödinger’s thoughts turned to poison, death, and destruction. Schrödinger’s cat, then, should remind us of more than the beguiling strangeness of quantum mechanics. It also reminds us that scientists are, like the rest of us, humans who feel—and fear…

More of this sad story at “How Einstein and Schrödinger Conspired to Kill a Cat.”

* Terry Patchett

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As we refrain from lifting the box’s lid, we might spare a thought for Charles Babbage; he died on this date in 1871.  A mathematician, philosopher, inventor and mechanical engineer, Babbage is best remembered for originating the concept of a programmable computer.  Anxious to eliminate inaccuracies in mathematical tables. By 1822, he built small calculating machine able to compute squares (1822).  He then produced prototypes of portions of a larger Difference Engine. (Georg and Edvard Schuetz later constructed the first working devices to the same design which were successful in limited applications.)  In 1833 he began his programmable Analytical Machine (AKA, the Analytical Engine), the forerunner of modern computers, with coding help from Ada Lovelace, who created an algorithm for the Analytical Machine to calculate a sequence of Bernoulli numbers— for which she is remembered as the first computer programmer.

Babbage’s other inventions include the cowcatcher, the dynamometer, the standard railroad gauge, uniform postal rates, occulting lights for lighthouses, Greenwich time signals, and the heliograph opthalmoscope.  He was also passionate about cyphers and lock-picking.

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“There is not a discovery in science, however revolutionary, however sparkling with insight, that does not arise out of what went before”*…

 

Analysis of an ancient codebreaking tablet has revealed that Babylonian astronomers had calculated the movements of Jupiter using an early form of geometric calculus some 1,400 years before we thought the technique was invented by the Europeans.

This means that these ancient Mesopotamian astronomers had not only figured out how to predict Jupiter’s paths more than 1,000 years before the first telescopes existed, but they were using mathematical techniques that would form the foundations of modern calculus as we now know it…

Look more closely at the foundations of modern calculus at “This ancient Babylonian map of Jupiter just changed history as we know it.”  And read the Science article reporting the findings here.

* Isaac Asimov

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As we calculate the differential, we might send radiant birthday greetings to James Alfred Van Allen; he was born on this date in 1914.   A space scientist who learned to miniaturize electronics during World War II, he was instrumental in establishing the field of magnetospheric research in space, and led the scientific community for the inclusion of scientific research instruments on space satellites.  The Van Allen radiation belts were named after him, following their discovery by his Geiger–Müller tube instruments in 1958 on the Explorer 1, Explorer 3, and Pioneer 3 satellites during the International Geophysical Year.

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Written by LW

September 7, 2016 at 1:01 am

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