''Cycles of Time: An Extraordinary New View of the Universe'' is a science book by mathematical physicist

Roger Penrose Sir Roger Penrose (born 8 August 1931) is an English mathematician, mathematical physicist, Philosophy of science, philosopher of science and Nobel Prize in Physics, Nobel Laureate in Physics. He is Emeritus Rouse Ball Professor of Mathematics i ...

published by The Bodley Head in 2010. The book outlines Penrose's Conformal Cyclic Cosmology (CCC) model, which is an extension of

general relativity General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the differential geometry, geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of grav ...

but opposed to the widely supported multidimensional string theories and cosmological inflation following the

Big Bang The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models based on the Big Bang concept explain a broad range of phenomena, including th ...

Synopsis

Penrose examines implications of the Second Law of Thermodynamics and its inevitable march toward a maximum

entropy Entropy is a scientific concept, most commonly associated with states of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynamics, where it was first recognized, to the micros ...

state of the

universe The universe is all of space and time and their contents. It comprises all of existence, any fundamental interaction, physical process and physical constant, and therefore all forms of matter and energy, and the structures they form, from s ...

. Penrose illustrates entropy in terms of information state

phase space The phase space of a physical system is the set of all possible physical states of the system when described by a given parameterization. Each possible state corresponds uniquely to a point in the phase space. For mechanical systems, the p ...

(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 hole A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. Th ...

s. 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 Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physi ...

breaks down into extremely red-shifted

photon A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless particles that can ...

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. Penrose cites concentric rings found in the WMAP

cosmic microwave background The cosmic microwave background (CMB, CMBR), or relic radiation, is microwave radiation that fills all space in the observable universe. With a standard optical telescope, the background space between stars and galaxies is almost completely dar ...

survey as preliminary evidence for his model, as he predicted black hole collisions from the previous aeon would leave such structures due to ripples of gravitational waves.

Reception

Most nonexpert critics (nonscientists) have found the book a challenge to fully comprehend; a few such as '' Kirkus Reviews'' and Doug Johnstone for ''

The Scotsman ''The Scotsman'' is a Scottish compact (newspaper), compact newspaper and daily news website headquartered in Edinburgh. First established as a radical political paper in 1817, it began daily publication in 1855 and remained a broadsheet until ...

'' appreciate the against the grain innovative ideas Penrose puts forth. Manjit Kumar reviewing for ''

The Guardian ''The Guardian'' is a British daily newspaper. It was founded in Manchester in 1821 as ''The Manchester Guardian'' and changed its name in 1959, followed by a move to London. Along with its sister paper, ''The Guardian Weekly'', ''The Guardi ...

'' admires the Russian doll geometry play of the CCC concept, framing it as an idea of which M. C. Escher "would have approved". Graham Storrs for the ''New York Journal of Books'' concedes that this is not the book that an unambitious lay person should plunge into. The American fiction writer Anthony Doerr in ''

The Boston Globe ''The Boston Globe,'' also known locally as ''the Globe'', is an American daily newspaper founded and based in Boston, Massachusetts. The newspaper has won a total of 27 Pulitzer Prizes. ''The Boston Globe'' is the oldest and largest daily new ...

'' writes "Penrose has never shied away from including mathematics in his texts, and kudos to his publisher for honoring that wish. That said, the second half of ''Cycles of Time'' offers some seriously hard sledding"; "If you'll forgive a skiing metaphor, ''Cycles of Time'' is a black diamond of a book."

References

{{DEFAULTSORT:Cycles of Time (book) 2010 non-fiction books Cosmology books Information theory Popular physics books The Bodley Head books Works by Roger Penrose