Cycles of Time

Cycles of Time: An Extraordinary New View of the Universe

Bodley Head 1st edition front cover
Author	Roger Penrose
Cover artist	Getty Images
Country	United Kingdom
Language	English
Subject	Science, Mathematics, Cosmology, Physics
Genre	Non-fiction
Publisher	Bodley Head (UK) Knopf (US)
Publication date	23 September 2010 May 3, 2011 (US)
Media type	Print (hardback)
Pages	288 pp.
ISBN
LC Class	QB991.C92 P46 2010
Preceded by	The Road to Reality
Followed by	Fashion, Faith, and Fantasy in the New Physics of the Universe

Cycles of Time: An Extraordinary New View of the Universe is a science book by mathematical physicist Roger Penrose published by The Bodley Head in 2010. The book outlines Penrose's Conformal Cyclic Cosmology (CCC) model, which is an extension of general relativity but opposed to the widely supported multidimensional string theories and cosmological inflation following the Big Bang.

Penrose examines implications of the Second Law of Thermodynamics and its inevitable march toward a maximum entropy state of the universe. Penrose illustrates entropy in terms of information state phase space (with 1 dimension for every degree of freedom) where particles end up moving through ever larger grains of this phase space from smaller grains over time due to random motion. He disagrees with Stephen Hawking's back-track over whether information is destroyed when matter enters black holes. Such information loss would non-trivially lower total entropy in the universe as the black holes wither away due to Hawking radiation, resulting in a loss in phase space degrees of freedom.

Penrose goes on further to state that over enormous scales of time (beyond 10¹⁰⁰ years), distance ceases to be meaningful as all mass breaks down into extremely red-shifted photon energy, whereupon time has no influence, and the universe continues to expand without event →∞. This period from Big Bang to infinite expansion Penrose defines as an aeon. The smooth “hairless” infinite oblivion of the previous aeon becomes the low-entropy Big Bang state of the next aeon cycle. Conformal geometry preserves the angles but not the distances of the previous aeon, allowing the new aeon universe to appear quite small at its inception as its phase space starts anew.