Would the universe turn out the same way twice?

[why06]

<p>So imagine we turned back our clock to the very beginning of time. Now all the initial conditions of our universe are the same as our present one was. Would that universe be a carbon-copy of our own universe. Or would it play out differently due to some sort of advanced probability that goes deeper than anything we have ever imagined. </p><p>If the universe does turn out the same. It must be a Newtonian Universe where everything is predictable</p><p>If the universe turns out different then that would imply that nothing can be assumed or predicted with a 100% certainty. </p> <div class="Discussion_UserSignature"> <div>________________________________________ <br /></div><div><ul><li><font color="#008000"><em>your move...</em></font></li></ul></div> </div>

 

[UFmbutler]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>So imagine we turned back our clock to the very beginning of time. Now all the initial conditions of our universe are the same as our present one was. Would that universe be a carbon-copy of our own universe. Or would it play out differently due to some sort of advanced probability that goes deeper than anything we have ever imagined. If the universe does turn out the same. It must be a Newtonian Universe where everything is predictableIf the universe turns out different then that would imply that nothing can be assumed or predicted with a 100% certainty. <br /> Posted by why06</DIV></p><p>It's difficult to believe that it would turn out the same.&nbsp; I would think it would be very similar, but since the structure of the universe relies quite a bit on the random motion of particles(extremely small anisotropies in the CMB for example), it's very difficult to believe it would be exactly the same.&nbsp;&nbsp;&nbsp; </p> <div class="Discussion_UserSignature"> </div>

 

[DrRocket]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>It's difficult to believe that it would turn out the same.&nbsp; I would think it would be very similar, but since the structure of the universe relies quite a bit on the random motion of particles(extremely small anisotropies in the CMB for example), it's very difficult to believe it would be exactly the same.&nbsp;&nbsp;&nbsp; <br />Posted by UFmbutler</DIV></p><p>I don't think anyone really knows.&nbsp; It is unlikely that the specific state of the universe would be precisely the same at a given point in time (if there is meaning to a specific point in time given the vagaries of general relativity).&nbsp; But there are many distinct states that are in practice indistinguishable from one another.&nbsp; It might well be that the universe would evolve in a series of states that is practically indistinguishable from those in which it has actually evolved.</p><p>The differences might be important on a small scale to a specific interested observer.&nbsp; But to an outside and disinterested observer the differences might well be insignificant.<br /></p> <div class="Discussion_UserSignature"> </div>

 

[derekmcd]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>So imagine we turned back our clock to the very beginning of time. Now all the initial conditions of our universe are the same as our present one was. Would that universe be a carbon-copy of our own universe. Or would it play out differently due to some sort of advanced probability that goes deeper than anything we have ever imagined. If the universe does turn out the same. It must be a Newtonian Universe where everything is predictableIf the universe turns out different then that would imply that nothing can be assumed or predicted with a 100% certainty. <br /> Posted by why06</DIV></p><p>I can't really think of any rational reason that the laws of physics would be any different that what we know (or don't know) today.&nbsp; With that said, I think even minor perturbation in the very first moments of the universe could have wide ranging effects that would certainly change the make-up of the universe.&nbsp; This wouldn't be a change in physics, just a change in structure.</p><p>Your guess is as good as mine...&nbsp;</p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[coeptus]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>So imagine we turned back our clock to the very beginning of time. Now all the initial conditions of our universe are the same as our present one was. Would that universe be a carbon-copy of our own universe. Or would it play out differently due to some sort of advanced probability that goes deeper than anything we have ever imagined. If the universe does turn out the same. It must be a Newtonian Universe where everything is predictableIf the universe turns out different then that would imply that nothing can be assumed or predicted with a 100% certainty. <br /> Posted by why06</DIV></p><p>&nbsp;</p><p>The new universe would be entirely and totally identical except you would have properly punctuated your second to the last sentence with a period.</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p><img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-wink.gif" border="0" alt="Wink" title="Wink" /></p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p><font color="#ff00ff">If not for bad Pluck, I'd have no Pluck at all . . .</font></p><p> </p><p><font color="#0000ff">This is your vogon, posting under coeptus, and trying IE and Firefox  to see if either is faster with fewer misloads.  Erf !!</font></p><p> </p><p> </p><p> </p> </div>

 

[centsworth_II]

<p><font color="#333399"><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I can't really think of any rational reason that the laws of physics would be any different that what we know (or don't know) today.<br /> Posted by derekmcd</DIV><br /></font>I'm surprised by this statement.&nbsp; Of course no-one knows why the physical laws would be different, but no-one knows why they would be the same either. A popular notion is that other universes may exist with different physical laws. You are not a fan of this idea?</p><p>The origin of the physical laws and why they are exactly the way they are is a very hot topic in the intelligent design debate.&nbsp; If there is only one universe and the physical laws of that universe could have been no different than what they are, the fact that they just happen to be right for life is very curious. I personally find the multiverse idea intellectually satisfying.&nbsp; Doesn't mean it's right though.</p> <div class="Discussion_UserSignature"> </div>

 

[derekmcd]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I'm surprised by this statement.&nbsp; Of course no-one knows why the physical laws would be different, but no-one knows why they would be the same either. A popular notion is that other universes may exist with different physical laws. You are not a fan of this idea?The origin of the physical laws and why they are exactly the way they are is a very hot topic in the intelligent design debate.&nbsp; If there is only one universe and the physical laws of that universe could have been no different than what they are, the fact that they just happen to be right for life is very curious. I personally find the multiverse idea intellectually satisfying.&nbsp; Doesn't mean it's right though. <br /> Posted by centsworth_II</DIV></p><p>Well, Why06 stipulated that the initial conditions are the same in his scenario.&nbsp; I see no reason why fundamental constants such as the gravitation constant, speed of light, planck's constant, etc should be any different.&nbsp;</p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[centsworth_II]

<p><font color="#333399"><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Well, Why06 stipulated that the initial conditions are the same in his scenario.<br /> Posted by derekmcd</DIV></font></p><p>It's hard to know what "<font color="#000000">initial conditions" means in this case.&nbsp; But if you look at the initial condition as a quantum superposition that can collapse in any number of ways, then there is no guarantee that it will collapse the same way even if the beginning superposition state is the same.&nbsp; &nbsp; </font></p> <div class="Discussion_UserSignature"> </div>