Installed sometime in 1997 - Latest update 26 Mar 2010.
Roger Penrose's Arrows Of Time (1)
2. Radiation - Non converging electromagnetic waves
3. Quantum - Heads and tails don't merge
4. Neutral Kaon - Disintegration rate rules out reversed time
5. Black Hole - No white holes
6. Universe - Collapsing universe would not reverse time
7. Entropy - Total entropy does not decrease
Other arrows of time
2. Cause precedes effect (finite transmission time)
Review of various viewpoints on time
Aristotle (384-322 BCE)
Archimedes (287?-212 BCE)
Saint Augustine (354--430)
Galileo Galilei (1564-1642)
Isaac Newton (1642-1727)
...the time variable does not appear explicitly in the mathematical formulation of the fundamental laws of physics. Indirectly, it is also associated with the fact that the laws of classical mechanics are reversible and do not distinguish between past and future. (2:20,21)
Newton assumed all forces acted at finite distances in an infinitely small time. This was indenspensible for the proof of his third law of equal action and reaction. (L. Brillouin, 4:107) Old classical mechanics assumed an absolute time, that corresponded to the idea that actions could be propagated at any distance instantaneously (meaning infinite velocity). (L. Brillouin, 4:108)
Of course the LAW OF INERTIA, which was also formulated by
Galileo and Newton, was thought by them to be an idealization, a
limiting law which was introduced only in order to get a simple
situation. Surely they thought that actual motions are irreversible, as
are all observable motions. Newton was very much concerned about
whether the orbits which he had calculated on the basis of the LAW
OF INERTIA were adequate approximations to the actual planetary
motions, which he thought were retarded by friction.
"We must...believe that there exists an even flow of time."
(Newton, as quoted by Gold) (3:188)
But at the same time he unwittingly introduced a paradox, by the fact
that the laws of dynamics which he formulated turned out to be
reversible in time. That was an unintended accident in his analysis.
But this did not worry people much because they still had the notion of
causality, implying a succession in time, namely that the effect follows
the cause. Yet even that possible basis for keeping an irreversibility of
the direction in the physical laws was undermined by Newton himself,
who introduced the force of gravity as an instantaneous action at a
distance. Surely he was aware of the paradoxical character of this
assumption, but he still insisted that it was the correct description of
the actual law of gravitation.
Joseph Lagrange (1736-1813)
Nicolas Carnot (1796-1832)
Rudolf Clausius (1822-1888)
[In this time frame people apparently began believing that Newton's approximations" of nature were "Laws" of nature and that nature was thus reversible. [rsf]
Physics was inconsistent: Newton's laws of motion were symmetrical, and the entropy law was asymmetrical to the direction of time. This difficulty was solved thanks to the illuminating work of many talented scientists,... (I. Szumilewicz) (4:182)
Ludwig Boltzmann (1844-1906)
Boltzmann believed that the two directions of time are indistinguishable. (2:6)
It is quite obvious that the Boltzmann equation, far from being a consequence of the laws of classical mechanics, is inconsistent with them. (Bergmann) (3:191)
Albert Einstein (1879-1955)
The Ritz and Einstein Agreement to Disagree (1909)
[PDF] Chapter 2 - The Time Arrow of Radiation - of H. D. Zeh's book,
The Physical Basis of the Direction of Time,
Prelim. 5th edn. (Mar-05):
Lewis (1930) [Winford Lewis (1878-1943)?]
Wheeler & Feynman
The dependence of the electromagnetic arrow of time on the thermodynamic arrow was a feature of the absorber theory formulated by Wheeler and Feynman (1945). In an attempt to produce a theory of charged elementary particles which avoided the difficulties that had beset previous theories of their interaction with electromagnetic fields, they introduced the hypothesis that every photon has an absorber as well as an emitter. In their theory an accelerated charged particle emits radiation equally into the past and future. In other words, retarded and advanced waves are generated symmetrically. If the radiation is confined to an opaque enclosure, so that all of it is absorbed, the waves striking the walls will cause the charged particles therein to radiate likewise into both the past and the future. Wheeler and Feynman showed that if the enclosure is fully opaque, the advanced waves emitted by the walls will just cancel those from the source particle and only the retarded waves will be left. ... Moreover, since all attempts to produce a quantum-mechanical version of the absorber theory lead to the same difficulties as previous theories of the interactions of charged particles with the electromagnetic field, there is no strong argument in its favour and in fact its original proponents have abandoned it. (2:341-342)
Levinson elaborates the idea.
"The Temple is to space as the Sabbath is to time."(7)
(1) Tony Rothman, Discover, Feb (1987).
(2) G. J. Whitrow, The Natural Philosophy of time, 2nd. ed. Clarendon Press, Oxford, (1984).
(3) Gold, T., The Nature of time, Cornell Univ. Press, (1967).
(4) J. Zeman, Time in Science and Philosophy, (1971).
(5) J.E. Hogarth, "Cosmological considerations of the absorber theory
(6) Encyclopedia Americana, Vol. 18, 502, (1960).
(7) A.J. Hershel, The Sabbath, p. 1; Levinson,
The Temple and the World, p. 298.
The Arrow of Electromagnetic Time and Generalized Absorber Theory
- John.G. Cramer.
Time's Arrow: Particles cannot go back to the future -
CERN Bulletin 47.98; 16 November 1998