From: (Tony Smith) Sender: (Yaneer Bar-Yam) To: complex-science Date: Wed, 06 Aug 2008 23:27:43 -0400 Message-ID: X-Original-Return-Path: Received: from [203.10.110.77] (HELO mail.netspace.net.au) by necsi.org (CommuniGate Pro SMTP 4.0.6) with ESMTP id 22508011 for complex-science@necsi.org; Wed, 06 Aug 2008 02:03:13 -0400 Received: from [10.0.1.198] (dsl-202-45-117-50-static.VIC.netspace.net.au [202.45.117.50]) by mail.netspace.net.au (Postfix) with ESMTP id 21E633771C9 for ; Wed, 6 Aug 2008 16:03:09 +1000 (EST) X-Original-Message-Id: <458DFEEE-E9D9-445C-82AF-5DCD9DD1BEA2@meme.com.au> X-Original-To: "(John McCrone)" In-Reply-To: Content-Type: multipart/alternative; boundary=Apple-Mail-35--822784451 Mime-Version: 1.0 (Apple Message framework v926) Subject: Isolated Universe? [was Re: How to avoid mis-interpreting ...] X-Original-Date: Wed, 6 Aug 2008 16:03:04 +1000 References: X-Mailer: Apple Mail (2.926) --Apple-Mail-35--822784451 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit On 06/08/2008, at 2:02 PM, (Sungchul Ji) wrote: > *The Universe by definition doesn't even have any boundary and hence > cannot exchange any matter or energy with it. I'm starting to see that reflexive acceptance of the assumption that such a definition is in any way related to the world we find ourselves in might be contributing significantly to lack of progress in understanding the bigger picture. At any moment, our cosmos can be seen as bound by various event horizons: the Big Bang at the Hubble radius and many black holes within. Those event horizons are all very porous, but each in one direction, the CMB flux entering from (near) the Big Bang horizon and anything that strays too close exiting through the black hole horizons. In 'Three Roads to Quantum Gravity', Lee Smolin argues that we can't know anything beyond these event horizons, then goes on to propose an evolutionary scenario connecting the two (a scenario I have some sympathy for but which I still doubt is yet sufficient to give us a full explanation for conservative physics by natural means). But the inference relevant here from Smolin's first point is that we should not use fact of the Big Bang to jump to a conclusion that even the complete "Universe" (for want of a better word) produced by the Big Bang is even bound, let alone Closed or Isolated in the sense Sung uses for clearly confined systems. I don't want to take this any further for now. It is just that I have developed an allergy to the reflexive assumption that local truths can be safely applied to global considerations. There is not even a way to get evidence as to whether they can or cannot. Tony Smith Complex Systems Researcher Meme Media Melbourne, Australia http://www.meme.com.au/ --Apple-Mail-35--822784451 Content-Type: text/html; charset=US-ASCII Content-Transfer-Encoding: quoted-printable
On 06/08/2008, at = 2:02 PM, (Sungchul Ji) wrote:

*The Universe by definition = doesn't even have any boundary and hence
cannot exchange any matter = or energy with it.

I'm starting to = see that reflexive acceptance of the assumption that such a definition = is in any way related to the world we find ourselves in might be = contributing significantly to lack of progress in understanding the = bigger picture.

At any moment, our cosmos can = be seen as bound by various event horizons: the Big Bang at the Hubble = radius and many black holes within. Those event horizons are all very = porous, but each in one direction, the CMB flux entering from (near) the = Big Bang horizon and anything that strays too close exiting through the = black hole horizons.

In 'Three Roads to Quantum = Gravity', Lee Smolin argues that we can't know anything beyond these = event horizons, then goes on to propose an evolutionary scenario = connecting the two (a scenario I have some sympathy for but which I = still doubt is yet sufficient to give us a full explanation for = conservative physics by natural means). But the inference relevant here = from Smolin's first point is that we should not use fact of the Big Bang = to jump to a conclusion that even the complete "Universe" (for want of a = better word) produced by the Big Bang is even bound, let alone Closed or = Isolated in the sense Sung uses for clearly confined = systems.

I don't want to take this any further = for now. It is just that I have developed an allergy to the reflexive = assumption that local truths can be safely applied to global = considerations. There is not even a way to get evidence as to whether = they can or cannot.




Tony Smith

Complex Systems = Researcher

Meme = Media

Melbourne, Australia

http://www.meme.com.au/

=

= --Apple-Mail-35--822784451--