On Tue, Jul 31, 2012 at 2:30 PM, meekerdb <[email protected]> wrote:
> On 7/31/2012 10:48 AM, Alberto G. Corona wrote: > > "The problem is to explain also why the entropy of the early universe was > so low. If you just accept that this is the case and also don't bother > about the very distant future, there is no problem. But if you assume that > time goes on from the infinite distant past and/or to the infinite distant > future, you have a problem, because smaller local low entropy states are > then more likely than the whole observable universe being in some low > entropy state." > > That make me think about the people that try to discover the whys of the > arrow of time by taking concepts like "beginning of the universe". That > presuposses the arrow of time that he is trying to demonstrate how it > arises in the first place. this is a circular reasoning. > > > No, it's not circular. Beginning is just the low entropy state. > > > All that he can demonstrate empirically is that it follows entropy, an > then, he is puzzled by the fact that entropy was so low at the "beginning" > > > The interesting question is why there is there uniformity in the different > 'arrows of time'. > Brent, You may enjoy these musings on that question: http://www.sidis.net/ANIMContents.htm I don't know how accurate it is, but it was written by someone regarded as one of the smartest of people from recent history. In any event, I found it quite interesting, and would be interested to hear other's thoughts about his ideas. Jason > Why does the local increase in thermodynamic entropy match the expansion > of the universe? Why does the radiation AoT match the quantum branching of > MWI? > > > > but if we take the idea of a block universe shaped as a four dimensional > bell with a singularity in the left ( see the figure that I linked), there > is no arrow of time here. is our life that goes along very short segments > from left to right in the middle of this figure. what we do is to > extrapolate this sort segment to the whole figure. But this is not right. > first, time is local, according with general relativity. How we extrapolate > it? by assuming that time progress in the universe in the direction that > we perceive causality, that is, in the direction of entropy increase. > > but even so, there is not a single arrow of time where entropy > increases. there are infinite lines of entropy increase/arrows of time > departin from the singularity, which diverge radially trough the bell and > extend to the right in the figure. > > If i´m right, the existence of a gradient of entropy and, thus the > existence of a singularity with maximum entropy somewhere, at a point which > we consider "origin of the universe", is a pre-requisite for natural > selection and life. Natural selection (as I said before) select "good > correlations" which deal with macroscopical events, to design life and > observers. That is why we see this universe with such unavoidable notion of > beginning and not other in other ways. > > A boltzman brain is just a curiosity, unless the bolzman fluctionation > create not a single brain but a local portion of the universe that develop > in a way that maintain intellgent beings. In this case, it > is indistinguishable if the universe is or not the product of a boltzman > fluctuation. > > > The problem is that statistical mechanical estimates of probabilities > favor the random occurrence of the curiosity over the universe. > > Brent > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/everything-list?hl=en. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/everything-list?hl=en.
