Abram, With General Relativity, time is so geometrical that you can make it circular. (Cf the Gödel's solutions to Einstein's GR Equation, which gives hope to some to build a time machine, and even infinite computers!).

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Give me just a sufficiently massive cylinder ... Bruno On 06 Jan 2009, at 12:51, Bruno Marchal wrote: > > Abram, > > I agree with Brent. In relativity theory space and time are > intermingled in a geometrical way to give the Minkowski structure. > Actually you can make it into an Euclidian space by introducing an > imaginary time t' = sqr(-1)*t = it. The metrics becomes dx^2 + dy^2 + > dz^2 + dt'^2. > In quantum mechanics the possible position of an object on a line > gives > rise to an hermitian space: it is infinite dimensional, but there is > still a geometrical structure, with notions akin to angles and > distances. Of course mathematician have far more general notion of > dimensional spaces, some of which have nothing to do with geometry. In > physics metrics play always some role somewhere though. > > Bruno > > > Le 06-janv.-09, à 02:59, Brent Meeker a écrit : > >> >> Abram Demski wrote: >>> Thomas, >>> >>> If time is merely an additional space dimension, why do we >>> experience >>> "moving" in it always and only in one direction? Why do we remember >>> the past and not the future? Could a being move in some spatial >>> dimension in the same way we move through time, and in doing so >>> treat >>> time more like we treat space? Et cetera. >>> >>> To my knowledge, modern physics treats many things as "dimensions": >>> not just time and space, but also forces such as electromagnetism. >>> This does not imply that such things are spatial in nature. A >>> dimension is just a variable. Unless you think there is something >>> particularly spatial about time? >> >> There is something spatial about time, duration is measured along >> paths in >> space. Coordinate time is mixed with space by Lorentz symmetries. >> But it's >> still different from space. Lee Smolin and Fotini Markopolo have >> argued that >> time must be considered fundamental (no block universe). >> >> Brent >> >> >>> >> > http://iridia.ulb.ac.be/~marchal/ > > > > http://iridia.ulb.ac.be/~marchal/ --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to everything-l...@googlegroups.com To unsubscribe from this group, send email to everything-list+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/everything-list?hl=en -~----------~----~----~----~------~----~------~--~---