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tisdag 14 januari 2014

What Science is Ready for Retirement?

The Edge web site hosts a collection of 173 articles on the theme What Science is Ready for Retirement? including the following highlights in my view:
  • Anton Zeilinger: There is No Reality in the Quantum World
  • Alan Gut: The Universe Began In A State Of Extraodinarily Low Entropy
  • Kai Krause: The Uncertainty Principle
  • Bruce Parker: Entropy
  • Frank Tipler: String Theory
  • David Deutsch: Quantum Jumps
  • Andrew Lih: Calculus
  • Matt Ridley: Malthusianism
  • Lee Smolin: The Big Bang was the First Moment of Time
  • Freean Dyson: The Collapse of the Wave Function
  • Haim Hariri: The Discovery of the Higgs particle Closes a Chapter in Particle Physics
  • Max Tegmark: Infinity
  • Frank Wilczek: Mind versus Matter
What I could add is for example
  • relativity theory
  • multidimensional linear Schrödinger equation
  • statistical mechanics
  • statistical interpretation of quantum mechanics
  • Kutta-Zhukovsky lift theory for flight
  • Prandtl boundary layer theory for drag.
  • Contemporary physics has lost contact with physical reality. Mysticism and fancy has resulted in quite irrational notions being proposed to account for the physical Universe. This conference is a return to rational physics in terms that are comprehensible to any educated person, not just a small group of specialists.
See further Kritische Stimmen zur Relativitätstheori where some of my own critical work is presented. 

onsdag 24 april 2013

Time Is Real

Not Even Wrong reports in Time Reborn that
  • Lee Smolin’s new book, Time Reborn, is out today. For more about the ideas in the book, see video of a talk here, and an interview here.
The talk is summarized as follows:
  • What is time? Is our perception of time passing an illusion which hides a deeper, timeless reality? Or is it real, indeed, the most real aspect of our experience of the world? Einstein said that "the distinction between past, present, and future is only a stubbornly persistent illusion," and many contemporary theorists agree that time emerges from a more fundamental timeless quantum universe. But, in recent cosmological speculation, this timeless picture of nature seems to have reached a dead end, populated by infinite numbers of imagined unobservable universes. 
  • In his talk, Lee Smolin explains why he changed his mind about the nature of time. Like many fellow theorists, he used to believe time is an illusion, but he now embraces the view that time is real and everything else, including the laws of nature, evolves. Drawing from his new book, Time Reborn, Smolin explains how the great unsolved problems in physics and cosmology may be solved by adopting the view of a real time. then he will go beyond physics to explain how our view of time affects how we think of everything from our personal and family lives to how we face major problems such as climate change and economic crisis. In a world in which time is real, the future is open and there is an essential role for human agency and imagination in envisioning and shaping a good future.
This is in the line of my own ideas exposed in The Clock and the Arrow and Many-Minds Relativity.
Time is real, while the reality of the rest can be debated.

torsdag 20 december 2012

The Arrow of Time and Another New Year

As the year 2012 is now coming to an end it is maybe again time to contemplate the irreversibility of the world and our lives in particular. A clock can be made to tick backwards, but not our lives. A clock is reversible but our life is irreversible. Why? Why is there an arrow of time pointing from past to future?

The standard answer you hear is that by the 2nd law of thermodynamics the entropy always increases and increasing entropy is what defines the direction of time. If you say that you don't understand, then you are in good company: The clever mathematician John von Neumann pointed out that referring to entropy is a secure way of winning any argument, because nobody knows what entropy is. So, refereeing to increase of entropy as the definition of increase of time, says nothing.

If you are interested in understanding irreversibility and why you get older as time passes, you may get wiser by browsing The Clock and the Arrow: A Brief Theory of Time, where a new approach is explored based on an idea of finite precision computation.

The basic idea is illustrated in the picture above showing two sawlike structures on top of each other, which can slide with respect to each other one way, but not the other.  Why?

Because, what happens pulling the top structure to the right with a certain force F, assuming the bottom structure is fixed, is that the top structure moves right while being lifted up,  and the speed of motion is then determined by the power supplied and the weight of the top structure.

But motion to the left is impossible, because an infinite power would required to lift the top structure
the saw-teeth depth in zero time.

Why is then our lives like a saw gliding on top of another always to the right, towards an inescapable end without possibility to return? This is what the Clock and Arrow book seeks to explain. Take a look if you feel you want to know.

måndag 21 februari 2011

The Mystery of the 2nd Law Eliminated

One of the many common mysterious explanations of the concept of entropy as "measure of disorder". Very mysterious indeed, or do claim that you understand and can explain?

The 2nd Law of Thermodynamics has remained a mystery ever since it was formulated in the mid 19th century by Carnot, Clausius and Lord Kelvin.

The 2nd Law in its conventional formulation involves the concept of entropy S and the 2nd Law states that the entropy of a closed system can only increase in time, never decrease, that is
  • dS/dt > 0 (or dS/dt = 0)
where dS/dt is the time derivative of S.

The trouble with this formulation is that quantity denoted by S and named entropy, does not seem to have a well defined physical meaning as expressed by von Neumann to Shannon:
  • No one knows what entropy is, so if you in a debate use this concept, you will always have an advantage.
So the 2nd Law says that the entropy cannot decrease, but since "no one knows what entropy is", the statement of the 2nd Law is mysterious. Now, science based on mystery is not science, but all efforts to give entropy a clear physical meaning have failed.

The question then comes up if there is a formulation of the 2nd Law without the mysterious concept of entropy, a formulation involving only understood concepts?

Yes, there is an alternative formulation presented in the new book Computational Thermodynamics in terms of kinetic energy K, heat energy E, work W and turbulent dissipation D, which takes the following principal form without exterior forcing:
  • dK/dt = W − D,
  • dE/dt = − W + D,
  • D > 0,
where the condition D > 0 replaces the condition dS/dt > 0. The advantage of this formulation is that turbulent dissipation D with its sign D > 0 (or D = 0) is a physical concept which can be

We see that the 2nd Law expresses an irreversible transfer of kinetic energy into heat energy, while the total energy
  • TE = E + K
remains constant, as is seen by summing the two equations to get:
  • dTE/dt= dE/dt + dK/dt = 0.
We see that the work W transforms heat energy into kinetic energy or kinetic energy into heat energy depending on the sign of W:
  • In expansion with W positive, heat energy transforms into kinetic energy,
  • In compression with W negative, kinetic energy transforms into heat energy.
On the other hand, since D > 0 (or D = 0), turbulent dissipation can only transform kinetic energy into heat energy, and not heat energy into kinetic energy.

When you rub your hands they get warm, but you cannot get your hands rubbing by only heating them. Motion can generate heat by friction, but heat cannot generate motion by an inverse process of friction.

In the book you will discover a mathematical explanation of this familiar experience based on a concept of finite precision computation, which represents a new way of viewing physics as a form of analog computation of finite precision which can be simulated by digital computation.

So if you don't like to live with mysteries, take a look in the book see if you get the message.

If you want to get the message expressed in less technical form, you are invited to browse the
dialog between Mat and Phil in the likewise new book The Clock and the Arrow: A Brief Theory of Time exhibiting the connection between the 2nd Law and the Arrow of Time, that is why we get older and never younger.