Post on 21-May-2015
description
George Musser6 June 2009
The Matter of Time
http://www.cs.adelaide.edu.au/~paulc/physics/picasso.gif
1. How Physicists Visualize Time
Basic Model of Nature
The world at one
moment
The world a moment
later
Laws of physics
Spacetime
Spacetime
2. Time Is Special
Objectivity of Cause-Effect Relations
AB A
B
A B A B
A B
3. Our Experience of Time
Basic Mystery of Time
There’s a disconnect between time in physics and time in everyday life.
a. Arrow of time
The Arrow of Time
Scientific American, Jun 08
The Arrow of Time
Big Bang
Basic Mystery of Time
There’s a disconnect between time in physics and time in everyday life.
a. Arrow of timeb. Flow of time
Flow of Time
Basic Mystery of Time
There’s a disconnect between time in physics and time in everyday life.
a. Arrow of timeb. Flow of timec. Problem of frozen time
Resculpting Spacetime
Problem of Frozen Time
Space at one
moment
Space a moment
later
General relativity
EQUIVALENT
4. The Emergence of Time
The Fine Structure of Spacetime
American Scientist, Nov/Dec 91
Relational Time
t
5. Conclusion
Where Does Time Come From?
The everyday properties of time must emerge from physical time …
… which might itself emerge from deeper, timeless ingredients.
http://www.timereverse.com/brochure.asp (top); http://www.motivatedphotos.com/?id=6545 (bottom)
For More
For a copy of the slides, visit www.strings.musser.com
Backup Slides
Basic Model of Nature
Initial state
Final state
Statespace
Space and Time
Spacetime
http://casa.colorado.edu/~ajsh/sr/construction.html#grid
Each of us moves into the futureat his or her own pace.
The Arrow of Time
Fresh egg
Partially broken egg
Completely broken egg
Why did it begin here?
Where Life Fits Infood oxygen TLC
heat bodily waste
Does Time Matter At All?
Time present and time pastAre both perhaps present in time future,And time future contained in time past.If all time is eternally presentAll time is unredeemable.
—T. S. Eliot, Four Quartets
Emergence of Classical Spacetime
Scientific American, Jul 08
The Tree of
Physics
Mercury Nov/Dec 97
But that's a puzzle. The microscopic laws of physics,governing the behavior of individual objects, areperfectly reversible – they work equally well runningforwards and backwards in time.
Why is the collective behavior of macroscopic objectsirreversible, while the behavior of the individualconsitutents is perfectly reversible?
http://commons.wikimedia.org/wiki/File:Boeing_737-73V_-_EasyJet_Airline_-_G-EZJI_-_LEMD.jpg (top); http://upload.wikimedia.org/wikipedia/commons/6/60/CandlestickTelephones.jpg (bottom)
http://en.wikipedia.org/wiki/File:Arbor_Lake-Aerial.JPG (top); http://hoboken411.com/wp-content/uploads/2009/03/text-messaging-at-dinner.jpg (bottom)