ivan77 Posted October 17, 2004 Share Posted October 17, 2004 I am slightly confused by this issue, as i understand just before the big bang there was a state of very low entropy which over time to the present day increased (because of the bang). My question is how can there be ordered structures like galaxies ,planets and humans if entropy is supposed to increase over time. I know that its obvious gravity is responsible for matter coming together in stars etc but i dont know the full reason for the argument of entropy increasing with time. Link to comment Share on other sites More sharing options...
fuhrerkeebs Posted October 17, 2004 Share Posted October 17, 2004 Because entropy is allowed to decrease in local, open systems, such as a galaxy, or a planet. Link to comment Share on other sites More sharing options...
ivan77 Posted October 17, 2004 Author Share Posted October 17, 2004 Would u care to elaborate on that point, why is entropy only allowed to decrease in local regions of space? Link to comment Share on other sites More sharing options...
[Tycho?] Posted October 17, 2004 Share Posted October 17, 2004 The net entropy of a system always increases. It can decrease in some places, as long as it increases by a bunch in another area. Link to comment Share on other sites More sharing options...
Ophiolite Posted October 18, 2004 Share Posted October 18, 2004 I find it interesting that it is only because of 'local' exceptions that planets formed, life evolved, and we can figure out the principles of thermodynamics. As to why such exceptions should proceed in this way, I lean with those who feel there are several levels of self-organising characteristics inherent in matter. [i have to go now. There is a crowd at the castle gates,with torches, chanting 'weak anthropic principle', over and over.] Link to comment Share on other sites More sharing options...
granDODyssey Posted October 27, 2004 Share Posted October 27, 2004 the crude example is.... if you regard your study room or bed room as a closed system, the entropy(disorder) of your room has some inital value...say...like you put your belongings ( books , cloths ) in neat and orderly fashion...so the entropy will be initally low... and let's say there is a big bang in your room and everything get scattered around...and the entropy get higher.... In hoping that you will lower the "higher entroy" by placing "things" back to their places..., something unexpected happened that....although you may have succeeded in "ordering" your belongings, you have had to exert some force to accomplish the work as well. That means you lower the room's entropy, by the price of increasing it in your own body. (like your muscles contract <= your cells burn carbs <= molecules breaks down <=...etc.) so the overall entropy of a system is always increasing.... Link to comment Share on other sites More sharing options...
Sorcerer Posted October 27, 2004 Share Posted October 27, 2004 I always used to tell my mum it was futile, it will just get messy again.... never thought to use thermodynamics to argue the point though. Link to comment Share on other sites More sharing options...
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