Posts Tagged ‘Oresme’

Earth’s Core Is Younger Than Its Crust

May 30, 2016

Inner parts of the Earth are younger than the surface by an appreciable amount. Richard Feynman made this point first. But he underestimated the effect by a factor of 100 times! As the Danes who just discovered that put it: “The pedagogical value of this discussion is to show students that any number or observation, no matter who brought it forward, must be critically examined”.

Local Time is a theory invented by Poincaré, to make sense of Lorentz’s work. Local Time became famous when Einstein, a German, advertised it, and was himself advertised by Kaiser nationalists such as Max Planck. A gravitational field slows down (Local) Time. (The proof is easy.)

Notice that the core itself has no gravitation. So actually the slowing down of light clocks is a function of depth. Local time really slows down.

Local time, as given by light clocks, has to be the same as local time given by the weak force (radioactive decay). If not, one could tell absolute motion easily from the inside the bowels of the ship lab. That would contradict the Principle of Relativity.

I have argued for decades that the Cosmic Background Radiation gave an absolute frame. However, the situation is a bit more subtle than that. Galileo argued that a laboratory in the bowels of a ship cannot provide an indication of motion (as long as one does look outside!)

I recently dug around and found the argument came initially from bishop Oresme, a student and collaborator of Buridan. Both were major philosophers, mathematicians and physicists of the Fourteenth Century in Paris. Oresme considered the principle of relativity self-obvious (to “intelligent” persons). However that was as long as one was in the bowels of a ship, and not looking at heavenly bodies. Oresme explicitly said. Because Oresme argued the diurnal motion of Earth around itself could not be detected inside a lab (many centuries later, five centuries later, more exactly, that turned out to be false: consider Foucault’s pendulum, 1851 CE).

So can we find a sort of Foucault pendulum for absolute linear motion? General Relativity insists on what Newton already knew: the Earth falls around the Sun. Can we detect this rotation inside a mine, 2 kilometers down? In theory, yes: the CBR will slow down the Earth sometimes, and push it, at other times. A supersensitive accelerometer could detect that.

Nor can we do away with the likes of a CBR like reference frame. The simple fact that there are galactic clusters all around and they generate the gravitational field defines a state of rest relative to it.

The formalism of Quantum Physics already has an absolute time for all to see. That absolute time is what enables the non-local effects.

So is physics finished? No. Will the philosophical approach help? Of course (roll over, Feynman, go back to your faulty computations!). It took 32 years for physicists to realize that the potential was on the right side of the De Broglie-Schrodinger equation of 1924… That provided immediately with (the idea for) an experimental confirmation, the Bohm-Aharanov effect…
Patrice Ayme’

ianmillerblog

There was a rather interesting announcement recently: three Danes calculated that the centre of the earth is 2.5 years younger than the crust ( U I Uggerhøj et al. The young centre of the Earth, European Journal of Physics (2016). DOI: 10.1088/0143-0807/37/3/035602 ). The concept is that from general relativity, the gravitational field of earth warps the fabric of space-time, thus slowing down time. This asserts that space-time is something more than a calculating aid and it brings up a certain logic problem. First, what is time and how do we measure it? The usual answer to the question or measurement is that we use a clock, and a clock is anything that has a change over a predictable period of time, as determined by some reference clock. One entity that can be used as a clock is radioactive decay and according to general relativity, that clock at the core…

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BURIDAN: Momentum, Force, Inertia, Middle Ages…

March 20, 2016

When did mechanics and calculus of the Seventeenth Century start? Well, around 1350 CE, in Paris, thanks to the genius Buridan, and his students.

WHAT’S MASS? It is not an easy question. An answer for inertial mass was given seven centuries ago. Astoundingly, it’s still the foundation of our most modern physics. Let me explain. (And the thinker who suggested this, Buridan, used this new mechanics to suggest that the Earth turned around the Sun, and generally planets went into circular orbits; thanks to Catholic terror, most physicists, let alone the Plebs, have any inkling of this: religious terror works!)

Momentum, force, and inertial mass were defined from trajectory deviation, first. This, I will show below, is incredibly modern (the idea is found in Riemann ~ 1860 CE, as I explained within the text of “Quantum Trumps Spacetime”). This was all in Buridan’s work, in the Fourteenth Century (14C).  Jean Buridan postulated the notion of motive force, inventing a notion he named impetus… which is exactly momentum (= mv). Consider this, from Buridan’s Quaestiones super libros De generatione et corruptione Aristotelis:

When a mover sets a body in motion he implants into it a certain impetus, that is, a certain force enabling a body to move in the direction in which the mover starts it, be it upwards, downwards, sidewards, or in a circle. The implanted impetus increases in the same ratio as the velocity. It is because of this impetus that a stone moves on after the thrower has ceased moving it. But because of the resistance of the air (and also because of the gravity of the stone) which strives to move it in the opposite direction to the motion caused by the impetus, the latter will weaken all the time. Therefore the motion of the stone will be gradually slower, and finally the impetus is so diminished or destroyed that the gravity of the stone prevails and moves the stone towards its natural place. In my opinion one can accept this explanation because the other explanations prove to be false whereas all phenomena agree with this one

 In 14 C, In The Late Middle Ages, Buridan Defined Momentum And Force By Considering Deviation Of Particle Trajectory

In 14 C, In The Late Middle Ages, Buridan Defined Momentum And Force By Considering Deviation Of Particle Trajectory

Buridan writes an explicit formula:  impetus = weight x velocity. Just a word of the modernity of it all: the idea translates directly into defining force(s) with changes of distance between geodesics (in differential manifold theory). Also Buridan launches the vector theory of force (the impetus goes in the direction of the force imparted)… and the force of gravity. (Buridan identifies implicitly gravitational and inertial mass, another correct assumption.)

Buridan states that impetus = weight x velocity (modern momentum). All the predecessors of Buridan thought one needed a force to keep on moving, but Buridan did not. Famous predecessors such as Hibat Allah Abu’l-Barakat al-Baghdaadi, who modified Avicenna’s theory, which followed John Philoponus believed in inertia NOT. They all followed Aristotle, who believed all and any motion died away, if no force was applied. (Not to say no Muslim ever invented anything scientific: the Uzbek ibn-Musa al-Khowarizmi crucially put the finishing touch on the zero, which he partly got from India, in the Ninth Century.)

Buridan’s pupil Dominicus de Clavasio in his 1357 De Caelo, pointed out that this extended to gravity:

“When something moves a stone by violence, in addition to imposing on it an actual force, it impresses in it a certain impetus. In the same way gravity not only gives motion itself to a moving body, but also gives it a motive power and an impetus, …”.

Buridan knew celestial bodies were moving from inertia: “God, when He created the world, moved each of the celestial orbs as He pleased, and in moving them he impressed in them impetuses which moved them without his having to move them any more…And those impetuses which he impressed in the celestial bodies were not decreased or corrupted afterwards, because there was no inclination of the celestial bodies for other movements. Nor was there resistance which would be corruptive or repressive of that impetus.”

By definition, inertial mass is what resists an applied force. The greater the resistance to a force, the greater the inertial mass of what it is applied to.

Buridan invented the tunnel thought experiment (and thus, the idea of thought experiments). If a tunnel were bored through the center of the Earth and a heavy body dropped into it, what would happen to it? Well, Buridan gave the correct answer, repeated as a good parrot by Galileo… nearly three centuries later:

Galileo Galilei expressed this fundamental principle of his dynamics in his 1632 Dialogo:

The heavy falling body acquires sufficient impetus [in falling from a given height] to carry it back to an equal height.

Buridan had many students: Buridan’s thought was pursued up by his pupil Albert of Saxony (1316–1390), by Poles such as John Cantius, and the Oxford Calculators Nicole Oresme pioneered the practice of demonstrating laws of motion in the form of graphs (equations weren’t available yet); some of these are now known as central and basic theorems of calculus (like the theorem of the mean, guessed in Oxford, proven by Oresme)

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Buridan’s Revolution:

Buridan introduced p = mv, called it “impetus” and stated that it did not change if no force was applied. Thus Buridan buried the complete idiocy known as Aristotle’s physics. (That Aristotle could be a complete idiot at the mental retard level is philosophically, and historically capital, as Aristotle set in place the leadership system through celebrities, which we enjoy to this day).

Buridan’s Inertia Law is known as Newton’s First Law (because Buridan was from Paris, while Newton demonstrates the superiority of the English born three centuries later by attributing to him what Isaac did not discover).

More generally Newton asserted clearly his Second Law: dp/dt = F (where  F is the Force, by definition). It’s an axiom. (Weirdly the Second Law implies the First…)

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Force = Deviation From Trajectory:

This is Buridan’s idea. It was taken over again by Bernhard Riemann, in the early 1860s (five centuries after Buridan’s death). In modern mathematical parlance, force is depicted by geodesic deviation. It’s this idea which is at the triple core of Einstein’s theory (with the idea that gravitation/spacetime is a field, and that it’s Newton’s theory, in first order).

So this is ultramodern: the idea got carried over in “Gauge Theories”, and, because there are several forces, there are many dimensions.

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Thought Experiment Often Precedes Experiment: 

Yesterday I bought a (2015) book by a (British academic) historian of science. In it, the honorably paid professional asserted modern science started with Tycho in 1572. Tycho, a Count set his student Kepler onto the refined study of the orbit of Mars. Both Tycho and Kepler were 5 star scientists (differently from, say Copernicus or Einstein, both of whom too little inclined to quote their sources). So they were, because, differently from, say, Obama, they had strong personalities. Great ideas come from great emotions. Tycho believed the Ancients had lied. And he was right, they had lied about the orbits of the planets: observations with the same instruments gave different results from the ones the Ancients had claimed.

The preceding shows that this trite notion is profoundly false; the scientific revolution was launched by Buridan and his students (among them Oresme, Albert of Saxony), contemporaries and predecessors (including Gerard de Bruxelles and the Oxford Calculators). Some of their work on basic kinematics, the exponential and the mean theorem of calculus was erroneously attributed to Galileo or Newton, centuries later.

To believe everything got invented around the seventeenth century is not to understand how the human mind works. Experience has to be preceded by thought-experiment (even Einstein understood that). Buridan and his contemporaries did the preliminary thinking (while others were making clocks and hydraulic presses). All of this would become immensely easier after the invention of algebra and Descartes’ analytic geometry, true.

So let’s have a loving and admirative thought for Buridan, the main author of the scientific revolution, whose reputation, and WISDOM was destroyed by the (TERRORIST) CATHOLIC STATE: Buridan’s astronomical reputation was destroyed by the Catho-fascists, more than a century after his death. That’s why the heliocentric system is attributed to an abbot from a rich family (Copernicus), instead of the master physicist said abbot was forced to read as a student.

Studying the history of science, and mathematics uncovers the fundamental axioms, in the natural order given by their obviousness.

Determining which ideas came first, and why is not about determining who is the brightest child, or most impressive bully in the courtyard. In 1907, Einstein made a big deal that he, Albert, was the discoverer of Energy = Mass (“E = mcc”). A careful inspection shows that this either reflects dishonesty, or misunderstanding on his part. Or both. I will address this soon, as I keep on studying mass and momentum.

Buridan put momentum at the core of physics, and thought-measured if dynamically. Momentum is still at the core: photons have momentum, but not mass.

It’s important to realize that many of the latest ideas in physics (all of “Gauge Theories”)  rest on an idea invented in Paris seven centuries ago. Not to slight it, or to heap contempt on all the noble Nobels. But, surely, the time has come for really new ideas!

Patrice Ayme’