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# Time

### Lee Smolin goes further in his book Time Reborn, arguing that not only is change real, but that indeed time may be the only thing that’s real. At the other end of the spectrum, Julian Barbour argues in his book The End of Time not only that change is illusory, but that one can even describe physical reality without introducing the time concept at all.”

― Max Tegmark, Our Mathematical Universe: My Quest for the Ultimate Nature of Reality

## What is entropy?

### We know from everyday experience how energy spreads out – and how it doesn’t. This ice melting looks normal.

commons.wikimedia.org/wiki/File:Melting_icecubes.gif

### Water molecules move randomly in water – so by sheer chance, couldn’t they all come together to spontaneously form ice cubes? Yet this obviously never happens.

The following is from: Entropy Explained, With Sheep: From Melting Ice Cubes to a Mystery About Time, by Aatish Bhatia, https://aatishb.github.io/entropy/

## Related articles

The Quantum Thermodynamics Revolution

Time’s Arrow Traced to Quantum Source

## Learning Standards

2016 Massachusetts Science and Technology/Engineering Curriculum Framework

HS-PS3-2. Develop and use a model to illustrate that energy at the macroscopic scale can be accounted for as either motions of particles and objects or energy stored in fields.
Clarification Statements: Examples of phenomena at the macroscopic scale could include evaporation and condensation, the conversion of kinetic energy to thermal energy,

HS-PS3-4a. Provide evidence that when two objects of different temperature are in thermal contact within a closed system, the transfer of thermal energy from higher temperature objects to lower-temperature objects results in thermal equilibrium, or a more uniform energy distribution among the objects and that temperature changes
necessary to achieve thermal equilibrium depend on the specific heat values of the two substances. Energy changes should be described both quantitatively in a single phase (Q =m·c·∆T) and conceptually either in a single phase or during a phase change.

Next Generation Science Standards

HS-PS3-4. Plan and conduct an investigation to provide evidence that the transfer of thermal energy when two components of different temperature are combined within a closed system results in a more uniform energy distribution among the components in the system (second law of thermodynamics).

Influence of Science, Engineering and Technology on Society and the Natural World: Modern civilization depends on major technological systems. Engineers continuously modify these technological systems by applying scientific knowledge and engineering design practices to increase benefits while decreasing costs and risks. (HS-PS3-3)

Changes of energy and matter in a system can be described in terms of energy and matter flows into, out of, and within that system. (HS-PS3-3)

Energy cannot be created or destroyed—only moves between one place and another place, between objects and/or fields, or between systems. (HS-PS3-2)

AP Physics

7.B.2.1: The student is able to connect qualitatively the second law of thermodynamics in terms of the state function called entropy and how it (entropy) behaves in reversible and irreversible processes. [SP 7.1]
– AP Physics Course and Exam Description

## Further notes

“About Time: Einstein’s Unfinished Revolution” Paul Davies VERY GOOD.
“The End of Certainty” Ilya Prigogine

“World in Process” John A. Jungerman Description of the ideas of modern physics and cosmology; also connects those ideas to process thought.

“Travels in Four Dimensions: The Enigmas of Space and Time” Robin Le Poidevin

“Time’s Arrows Today: Recent Physical and Philosophical Work on the Direction of Time”
Steven Frederick Savitt, Cambridge University Press, 1995

“Time and History: Proceeding of the 28 International Ludwig Wittgenstein Symposium” by Friedrich Stadler

Introducing Time, Third Edition, Totem Books; New Ed edition (June 25, 2005) Craig Callender

“The Ontology of Time” L. Nathan Oaklander, Studies in Analytic Philosophy, Prometheus Books
http://www.prometheusbooks.com/catalog/book_1532.html

http://en.wikipedia.org/wiki/Arrow_of_time

http://en.wikipedia.org/wiki/Block_time

http://en.wikipedia.org/wiki/Presentism_%28philosophy_of_time%29

http://en.wikipedia.org/wiki/Eternalism_%28philosophy_of_time%29

http://en.wikipedia.org/wiki/Endurantism

http://en.wikipedia.org/wiki/Perdurantism

http://plato.stanford.edu/entries/change/

http://plato.stanford.edu/entries/spacetime-bebecome/

http://plato.stanford.edu/entries/causation-backwards/

http://plato.stanford.edu/entries/time-experience/

See post by Moving Finger, http://www.physicsforums.com/showthread.php?t=124119&highlight=time