2009/8/24 Oleg Goldshmidt <[email protected]>: > I'll bite - it's OT, but too much fun to skip... ;-) > > 2009/8/24 Shachar Shemesh <[email protected]>: > >> As a side note - does that prove that our universe only has three >> dimensions? > > Technically, no, though many philosophers (as opposed to physicists or > mathematicians) will say it does. The number of dimensions does not > follow from R^-2, but if you live in a 3D world then R^-2 follows... > ;-) > > I have not checked every statement on > http://en.wikipedia.org/wiki/Spacetime#Privileged_character_of_3.2B1_spacetime, > but it does have useful pointers that I'd myself recommend. > [disclosure: I *am* a physicist]. > > The R^-2 character of gravity is arguably even more important than > radiation, but the mathematical reason is the same. > > If you are interested in proving that our world is 3D then probably > the most important set of physical/anthropic arguments that "derive" > N=3 from the observable universe was proposed by Ehrenfest (and Weyl: > Ehrenfest concentrated on gravity and Weyl on electromagnetism) in the > early 20ies - a reference is in the Wikipedia article above. > > For those interested in an in-depth discussion of why the Universe is > what it is I recommend "The Anthropic Cosmological Principle" by > Barrow & Tipler (see the reference in the Wikipedia link) - it's big, > but real fun to read, IMHO. Unfortunately, I don't have a copy and I > can't recall from memory how much background it assumes. >
Oleg, I understood that the universe has 11 or so dimensions, and that 5 or six can even be measured. But the wikipedia article that you link to claims only 3+1. I have googled a bit but found only very technical explanations, or baby facts with no explanations. Can you sum it up for someone who is familiar with relativity, but is not a physicist? Thanks. -- Dotan Cohen http://what-is-what.com http://gibberish.co.il _______________________________________________ Linux-il mailing list [email protected] http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
