Relativity, Cosmology, and Time

Time Reborn

In the "Time Reborn" by Lee Smolin, Vintage Canada, 2013, the author attributes the failure in contemporary physics to address certain problems such as the weird quantum interpretations, the unknowable initial condition of the universe, the inability to merge quantum theory with relativity, etc. to the degrading of time. Although we use clock to measure time daily, in the back of our mind there are always something with an eternal existence - be it the divine, or truth, or justice. For philosophers and physicists, it is the laws of nature that transcends time. Scientists work hard to "discover" the laws as if the regularities are always there, it is only our own ignorance that fails to comprehend. According to Lee Smolin such thinking may not be applicable to the scale of the universe. The laws of nature are evolving and by definition evolution must associate with time.

Figure 25 Time Reborn [view large image]

Thus, he asserts that time is absolute and essential in the new paradigm of physics especially on cosmology. The differences of this novel idea with the contemporary physics are summarized in the followings in the form of anti- vs pro- time dialogues.

• Nature of Time - The conventional wisdom considers time to be an illusion. Truth and reality are timeless. Physicists are not immune from this kind of thinking. The scientific laws can be applied to all time and space, so are the properties of certain parameters such as the mass of elementary particles, strength of the coupling constants, ... etc. The future is determined by the laws of physics. It is inconceivable to have such fundamental premises varied over space and time - the framework of physics will fall apart under such circumstance.
  
  On the other hand, the new paradigm takes time to be real and essential for the evolution of everything including scientific laws. What used to be considered as infallible truth is just one of the happenstances in a moment that is one of a succession of moments. Since the laws themselves evolve, the future is not totally predictable.


• Space and Geometry - Contemporary physics considers space and thus geometry as real. It provides a background scaffold upon which everything moves according to certain laws. It is here and everywhere irrespective of whether there is anything presence or absence in the foreground. General relativity relaxes the rule a little bit by allowing its generation with mass-energy density. In some theories, the universe is spatially infinite, which renders probabilistic predictions meaningless when outcomes from identical worlds are included.
  
  The new paradigm suggests that space (as we perceive it) is an emergent property arising from much smaller basic elements (see loop quantum gravity for a pre-absolute time version). In this new concept, the apparent space is defined by turning off most connections between things (more connections means higher dimension), and nothing means no space. The universe is spatially finite. Probabilities are ordinary relative frequencies.


• Beginning of Time - The standard cosmology defines the initial singularity as the beginning time and is inexplicable.
  
  The new paradigm identifies the Big Bang with the Big Bounce in one of its cosmic cycles. The event can be explained by the history of the universe before it.


• Cosmological Models - In some cosmological models such as the "Eternal Inflation", our observable universe is one of an infinite collection of simultaneously existing but unobservable universes.
  
  In the new paradigm, our universe is at a stage in a succession of eras of one universe. Fossils, or remnants, of previous eras may be observed in cosmological data.


• Complexity and the End - The observed complexity and order of our universe is a random accident due to a rare statistical fluctuation. It will end in an equilibrium state (heat death), in which matter and energy are uniformly distributed throughout the universe and nothing ever happens except rare random fluctuations, which would dissipate quickly constructing nothing.
  
  In the time-bound picture, the universe runs process for breeding novel phenomena and creating states of organization, which will forever renew itself to ever higher complexity. The universe would re-cycle itself but there is no end.


• Quantum Theory - It is a remarkably successful theory in contemporary physics, only its interpretation is still a controversial subject.
  
  Quantum theory is considered to be incomplete. New theory at higher level will replace probability with more intuitive interpretation.

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