(Roughly) Daily

Posts Tagged ‘Physics

“A measurement is not an absolute thing, but only relates one entity to another”*…

 

kilogram

 

Until now, [the mass of the kilogram] has been defined by the granddaddy of all kilos: a golf ball-sized metal cylinder locked in a vault in France [a replica of which is pictured above]. For more than a century, it has been the one true kilogram upon which all others were based…

Made of a corrosion-resistant alloy of 90 percent platinum and 10 percent iridium , the international prototype kilo has rarely seen the light of day. Yet its role has been crucial, as the foundation for the globally accepted system for measuring mass upon which things like international trade depend.

Three different keys, kept in separate locations, are required to unlock the vault where the Grand K and six official copies — collectively known as ‘‘the heir and the spares’’ — are entombed together under glass bell-jars at the International Bureau of Weights and Measures, in Sevres on the western outskirts of Paris.

Founded by 17 nations in 1875 and known by its French initials, the BIPM is the guardian of the seven main units humanity uses to measure its world : the meter for length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin for temperature, the mole for the amount of a substance and the candela for luminous intensity.

Of the seven, the kilo is the last still based on a physical artifact, the Grand K. The meter, for example, used to be a meter-long metal bar but is now defined as the length that light travels in a vacuum in 1/299,792,458th of a second…

The metal kilo is being replaced by a definition based on Planck’s constant, which is part of one of the most celebrated equations in physics but also devilishly difficult to explain . Suffice to say that the update should, in time, spare nations the need to occasionally send their kilos back to Sevres for calibration against the Grand K. Scientists instead should be able to accurately calculate an exact kilo, without having to measure one precious lump of metal against another…

More of this weighty story at “The kilogram is changing. Weight, what?

* H.T. Pledge, Science since 1500

###

As we muse on measurement, we might send well-calibrated birthday greetings to August Kundt; he was born on this date in 1839.  An astronomer-turned-physicist, he developed a method to measure the velocity of sound in gases and solids using a closed glass tube (now known as a Kundt’s Tube).

AugustKundt source

We might also spare a thought for another physicist, Niels Bohr; he died on this date in 1962.  A Danish physicist and philosopher, Bohr was the first to apply quantum theory to the problem of atomic and molecular structure, creating the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete, and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another– a model the underlying principles of which remain valid.  And he developed the principle of complementarity: that items could be separately analyzed in terms of contradictory properties, e.g., particles behaving as a wave or a stream. His foundational contributions to understanding atomic structure and quantum theory won him the Nobel Prize in Physics in 1922.

 source

 

“The information revolution came without an instruction manual”*…

 

Machines

In my graduate seminar we’ve recently been thinking a bit about machines. Given that our focus has been on the 19th Century, attention has been directed toward ergodic machines (from the root ergon meaning work). Ergodic machines are machines that run on heat and energy. Such machines are essentially mechanical in nature. They deal with basic physical mechanics like levers and pulleys, and questions of mass, weight, and counter-balance. Ergodic machines adhere to the laws of motion and inertia, the conservation of energy, and the laws of thermodynamics governing heat, pressure, and energy…

Still, ergodic machines do not account for all machines. Informatic machines, those devices dominating contemporary life, have in many ways taken over from their 19th-century counterparts. Informatic machines have physical bodies, of course, and they frequently require electricity or other forms of power to operate. However the essence of the informatic machine is not found in motion, unrest, heat, or energy. The essence of the informatic machine is found in form, not energy or presence. From the perspective of philosophy, computers are therefore quite classical, even conservative. They follow that most basic law of Western idealism, that the formal determines the physical

The anti-computer has yet to be invented. But traces of it are found everywhere. Even Bitcoin, that most miserable invention, relies on an anti-computational infrastructure. In order to mine coins, one must expend energy. Hence these twenty-first-century machines are yoked to a nineteenth-century mandate: burn fuel to release value. Bitcoin may run on a computer but it is anti-computational at heart. Bitcoin only works because it is grounded in an anti-computer (energy). It is thus a digital machine made subsidiary to an analog foundation, a twenty-first-century future tied to a nineteenth-century past.

The encryption algorithms at the heart of Bitcoin are anti-computational as well. Cryptography deploys form as a weapon against form. Such is the magic of encryption. Encryption is a kind of structure that makes life difficult for other competing structures. Encryption does not promote frictionlessness, on the contrary it produces full and complete friction at all levels. Not the quotidian friction of everyday life, but a radical friction frustrating all expression. What used to be a marginal activity practiced by hackers — cracking password hashes — is now the basis of an entire infrastructure. Earn a buck by cracking hashes using “brute force.” Turn your computer into an anti-computer.

A friend of Marshall McLuhan’s, Father John Culkin, SJ, a Professor of Communication at Fordham University, observed that “we shape our tools and then our tools shape us” (though the quote is often attributed to McLuhan, who may in fact have inspired it).   Alexander R. Galloway ponders the tools that dominate our lives these days: “Anti-Computer.”

* “The central paradox of the machines that have made our lives so much brighter, quicker, longer and healthier is that they cannot teach us how to make the best use of them; the information revolution came without an instruction manual”  — Pico Iyer

###

As we muse on machines, we might spare a thought for James Clerk Maxwell; he died on this date in 1879.  a mathematician and and physicist, his work in uniting electricity, magnetism, and light– that’s to say, formulating the classical theory of electromagnetic radiation— is considered the “second great unification in physics” (after the first, realized by Isaac Newton), and laid the foundation for modern physics, starting the search for radio waves and paving the way for such fields as special relativity and quantum mechanics.  In the millennium poll – a survey of the 100 most prominent physicists at the turn of the 21st century – Maxwell was voted the third greatest physicist of all time, behind only Newton and Einstein.

225px-James_Clerk_Maxwell source

 

Written by LW

November 5, 2018 at 2:01 am

“If you think this Universe is bad, you should see some of the others”*…

 

copernicus

FIRST OF FOUR?: The first Copernican revolution moved the Earth out of the center of the solar system. The second recognized that there are many planets in our galaxy, and the third that there are many galaxies in the observable universe. Proving that our universe is one among many would represent a fourth Copernican revolution.

 

A challenge for 21st-century physics is to answer two questions. First, are there many “big bangs” rather than just one? Second—and this is even more interesting—if there are many, are they all governed by the same physics?

If we’re in a multiverse, it would imply a fourth and grandest Copernican revolution; we’ve had the Copernican revolution itself, then the realization that there are billions of planetary systems in our galaxy; then that there are billions of galaxies in our observable universe. But now that’s not all. The entire panorama that astronomers can observe could be a tiny part of the aftermath of “our” big bang, which is itself just one bang among a perhaps infinite ensemble.

At first sight, the concept of parallel universes might seem too arcane to have any practical impact. But it may (in one of its variants) actually offer the prospect of an entirely new kind of computer: the quantum computer, which can transcend the limits of even the fastest digital processor by, in effect, sharing the computational burden among a near infinity of parallel universes…

Cambridge physicist and Astronomer Royal Martin Rees suspects that our universe is one island in an archipelago: “The Fourth Copernican Revolution.”

* Philip K. Dick

###

As we find our place, we might recall that it was on this date in 1884 that 41 delegates from 25 nations, meeting in Washington, DC for the International Meridian Conference, adopted Greenwich as the universal meridian.  They also established that all longitude would be calculated both east and west from this meridian up to 180°.

PrimeMeridianThm source

 

Written by LW

October 13, 2018 at 1:01 am

“I’ve never seen contraptions with so many dials and knobs before”*…

 

control panels

Control room, Klingenberg Power Station, Berlin, 1928. Photos by E.O. Hoppé.

 

Just one selection from the plethora of “dials, toggles, buttons, and bulbs” at “Control Panel.”

* “Lampy,” in The Brave Little Toaster

###

As we twist and turn, we might spare a thought for Guillaume Amontons; he died on this date in 1705.  A physicist who made formative contributions to the understanding of friction, he was also an accomplished designer of scientific instruments– perhaps most notably, the air thermometer, which relies on increase in volume of a gas (rather than a liquid) with temperature.  His approach led to the emergence of the concept of “absolute zero.”

amonton thermometer source

Amontons source

 

Written by LW

October 10, 2018 at 10:01 pm

“There will be time, there will be time”*…

 

Infinity-Time1

Poets often think of time as a river, a free-flowing stream that carries us from the radiant morning of birth to the golden twilight of old age. It is the span that separates the delicate bud of spring from the lush flower of summer.

Physicists think of time in somewhat more practical terms. For them, time is a means of measuring change—an endless series of instants that, strung together like beads, turn an uncertain future into the present and the present into a definite past. The very concept of time allows researchers to calculate when a comet will round the sun or how a signal traverses a silicon chip. Each step in time provides a peek at the evolution of nature’s myriad phenomena.

In other words, time is a tool. In fact, it was the first scientific tool. Time can now be sliced into slivers as thin as one ten-trillionth of a second. But what is being sliced? Unlike mass and distance, time cannot be perceived by our physical senses. We don’t see, hear, smell, touch, or taste time. And yet we somehow measure it. As a cadre of theorists attempt to extend and refine the general theory of relativity, Einstein’s momentous law of gravitation, they have a problem with time. A big problem…

The crisis inside the physics of time: “Is It Time to Get Rid of Time?

See also: “Forget everything you know about time.”

[image above: source]

* T. S. Eliot

###

As we check our watches, we might say a grateful Happy Birthday to Winsor McCay, the cartoonist and animator, who was born on this date in 1867.  His two best-known creations are the pioneering comic strip Little Nemo in Slumberland, which ran from 1905 to 1914, and the animated cartoon Gertie the Dinosaur (1914),which set the standard for animators for decades to come.

Little Nemo… for a more legible image, click here

 

Written by LW

September 26, 2018 at 1:01 am

“All you can do is hope for a pattern to emerge”*…

 

smiling_baby_10-1024x576

If you construct a Lego model of the University of London’s Senate House – the building that inspired the Ministry of Truth in George Orwell’s novel Nineteen Eighty-Four – the Lego blocks themselves remain unchanged. Take apart the structure, reassemble the blocks in the shape of the Great Pyramid of Giza or the Eiffel Tower, and the shape, weight and colour of the blocks stay the same.

This approach, applied to the world at large, is known as atomism. It holds that everything in nature is made up of tiny, immutable parts. What we perceive as change and flux are just cogs turning in the machine of the Universe – a huge but ultimately comprehensible mechanism that is governed by universal laws and composed of smaller units. Trying to identify these units has been the focus of science and technology for centuries. Lab experiments pick out the constituents of systems and processes; factories assemble goods from parts composed of even smaller parts; and the Standard Model tells us about the fundamental entities of modern physics.

But when phenomena don’t conform to this compositional model, we find them hard to understand. Take something as simple as a smiling baby: it is difficult, perhaps impossible, to explain a baby’s beaming smile by looking at the behaviour of the constituent atoms of the child in question, let alone in terms of its subatomic particles such as gluons, neutrinos and electrons. It would be better to resort to developmental psychology, or even a narrative account (‘The father smiled at the baby, and the baby smiled back’). Perhaps a kind of fundamental transformation has occurred, producing some new feature or object that can’t be reduced to its parts.

The notion of emergence can help us to see what’s going on here. While atomism is all about burrowing down to basic building blocks, emergence looks upward and outward, to ask whether strange new phenomena might pop out when things get sufficiently large or complex…

Does everything in the world boil down to basic units – or can emergence explain how distinctive new things arise?  Paul Humphreys helps us understand at “Out of nowhere.”

[Image above: source]

* Chuck Palahniuk, Lullaby

###

As we forage for the fundamental, we might send insightful birthday greetings to Ernest Everett Just; he was born on this date in 1883.  A pioneering biologist, academic, and science writer, he contributed mightily to the understanding of cell division, the fertilization of egg cells, experimental parthenogenesis, hydration, cell division, dehydration in living cells, and the effect of ultra violet rays on egg cells.

An African-American, he had limited academic prospects on his graduation from Dartmouth, but was able to land a teaching spot at Howard University.  Just met  Frank R. Lillie, the head of the Department of Zoology at the University of Chicago and director of the Marine Biological Laboratory (MBL) at Woods Hole, Mass.  In 1909 Lillie invited Just to spend first one, then several summers at Woods Hole, where Just pioneered the study of whole cells under normal conditions (rather than simply breaking them apart in a laboratory setting).  In 1915, Just was awarded the first Spingarn Medal, the highest honor given by the NAACP.

But outside MBL, Just experienced discrimination.  Seeking more opportunity, he spent most of the 1930s in various European universities– until the outbreak of WW II hostilities caused him to return to the U.S. in late 1940.  He died of pancreatic cancer the next year.

Ernest_Everett_Just source

 

Written by LW

August 14, 2018 at 1:01 am

“The truth is not always beautiful, nor beautiful words the truth.”*…

 

42436513724_9f5ac89201_o

 

Does anyone who follows physics doubt it is in trouble? When I say physics, I don’t mean applied physics, material science or what Murray-Gell-Mann called “squalid-state physics.” I mean physics at its grandest, the effort to figure out reality. Where did the universe come from? What is it made of? What laws govern its behavior? And how probable is the universe? Are we here through sheer luck, or was our existence somehow inevitable?

In the 1980s Stephen Hawking and other big shots claimed that physics was on the verge of a “final theory,” or “theory of everything,” that could answer these big questions and solve the riddle of reality. I became a science writer in part because I believed their claims, but by the early 1990s I had become a skeptic. The leading contender for a theory of everything held that all of nature’s particles and forces, including gravity, stem from infinitesimal, stringy particles wriggling in nine or more dimensions.

The problem is that no conceivable experiment can detect the strings or extra dimensions…

John Horgan examines physicist Sabine Hossenfelder‘s claim that desire for beauty and other subjective biases have led physicists astray: “How Physics Lost Its Way.”

* Lao Tzu, Tao Te Ching

###

As we contemplate certainty, we might recall that it was on this date in 1595 that Johann Kepler (and here) published Mysterium cosmographicum (Mystery of the Cosmos), in which he described an invisible underlying structure determining the six known planets in their orbits.  Kepler thought as a mathematician, devising a structure based on only five convex regular solids; the path of each planet lay on a sphere separated from its neighbors by touching an inscribed polyhedron.

It was a beautiful, an elegant model– and one that fit the orbital data available at the time.  It was, nonetheless, wrong.

Detailed view of Kepler’s inner sphere

source

 

 

Written by LW

July 9, 2018 at 1:01 am

%d bloggers like this: