29 Apr 05
I'm wondering why it is that generally, but especially during Carnivals or other big celebrations in cities, people don't tend to gather in the same place at the same time. Or perhaps they do but on the whole distribution seems to be relatively even. A friend told me that it was probably connected to the phenomenon which stops air molecules from gathering in one spot, thus preventing us from choking to death. Am I missing the obvious?
01 May 05
Originally posted by agoekjianthe second law of thermodynamics (aka: entropy) applied to crouds, nothing more.
I'm wondering why it is that generally, but especially during Carnivals or other big celebrations in cities, people don't tend to gather in the same place at the same time. Or perhaps they do but on the whole distribution seems to be relatively even. A friend told me that it was probably connected to the phenomenon which stops air molecules from gathering in one spot, thus preventing us from choking to death. Am I missing the obvious?
question: in more direct application, can entropy be dified?
the second law of thermodynamics is not really a 'law' per se, so is it possible to intentionaly and repeatedly reverse it?
07 May 05
Originally posted by fearlessleaderThis is the subject of Asimov's short story - "The Last Question". As the end of the universe draws nearer, the most sophisticated computer on earth is asked how to save humanity with the following question - Can the second law of thermodynamics be reversed?
the second law of thermodynamics (aka: entropy) applied to crouds, nothing more.
question: in more direct application, can entropy be dified?61
the second law of thermodynamics is not really a 'law' per se, so is it possible to intentionaly and repeatedly reverse it?
Apparently he thought it the best story he wrote.
07 May 05
Originally posted by agoekjianWith the possible exception of 'The Holmes-Ginsbook Device', it is the best story he wrote.
This is the subject of Asimov's short story - "The Last Question". As the end of the universe draws nearer, the most sophisticated computer on earth is asked how to save humanity with the following question - Can the second law of thermodynamics be reversed?
Apparently he thought it the best story he wrote.
07 May 05
Originally posted by agoekjianAt that point the computer is no longer on Earth.
This is the subject of Asimov's short story - "The Last Question". As the end of the universe draws nearer, the most sophisticated computer on earth is asked how to save humanity with the following question - Can the second law of thermodynamics be reversed?
Apparently he thought it the best story he wrote.
It is a pretty clever story.
07 May 05
Originally posted by agoekjianIf you look at the planet from space, humans are not randomly distributed. More are in cities than elsewhere, for example.
I'm wondering why it is that generally, but especially during Carnivals or other big celebrations in cities, people don't tend to gather in the same place at the same time. Or perhaps they do but on the whole distribution seems to be relatively even. A friend told me that it was probably connected to the phenomenon which stops air molecules from gathering in one spot, thus preventing us from choking to death. Am I missing the obvious?
If you look at a big celebration, people are also not randomly distributed. People will be more likely to be at a bar, near the stage, near the rides, near the food, etc.
There are similar processes going on with the people and the air molecules. However the laws of physics which describe why air particles are evenly distributed assume a homogenous environment. If there were some sort of factor like a hole to a vacuum on one side of a box then the air particles would not be evenly distributed. Similarly, humans encounter many things in their environment which affect how the humans will move, keeping them from moving completely randomly.
07 May 05
Originally posted by fearlessleaderNo, as far as I know, the 2nd Law cannot be defied. Entropy will increase in a closed system, period. The only way to decrease entropy is to increase it even more somewhere else.
the second law of thermodynamics (aka: entropy) applied to crouds, nothing more.
question: in more direct application, can entropy be dified?
the second law of thermodynamics is not really a 'law' per se, so is it possible to intentionaly and repeatedly reverse it?
07 May 05
Originally posted by AThousandYounghttp://prola.aps.org/abstract/PRA/v39/i10/p5378_1?qid=862748786df953f8&qseq=1&show=10
No, as far as I know, the 2nd Law cannot be defied. Entropy will increase in a closed system, period. The only way to decrease entropy is to increase it even more somewhere else.
maybe heat death isn't inevitable after all...
09 May 05
Originally posted by richjohnsoninteresting article...but wouldn't the Maxwell 'Demon' have to be able to get around that pesky Heisenberg Uncertainty Principle in order to determine when exactly to operate his shutter?
http://prola.aps.org/abstract/PRA/v39/i10/p5378_1?qid=862748786df953f8&qseq=1&show=10
maybe heat death isn't inevitable after all...
My feeling is that if you propose something that ends up violating the second law, then it's time to scrap that proposition and propose something else.
09 May 05
Originally posted by davegageI tend to agree with you, but some recent experiments have shown that the second law may be violated on a microscopic scale, which may have some interesting implications for nanotechnology.
interesting article...but wouldn't the Maxwell 'Demon' have to be able to get around that pesky Heisenberg Uncertainty Principle in order to determine when exactly to operate his shutter?
My feeling is that if you propose something that ends up violating the second law, then it's time to scrap that proposition and propose something else.
See:
http://www.aip.org/enews/physnews/2002/split/598-1.html
http://prola.aps.org/searchabstract/PRL/v89/i5/e050601?qid=36507ec175959a75&qseq=1&show=10
19 May 05
Originally posted by davegagecan you give a better explination of maxwell's demon?
interesting article...but wouldn't the Maxwell 'Demon' have to be able to get around that pesky Heisenberg Uncertainty Principle in order to determine when exactly to operate his shutter?
My feeling is that if you propose something that ends up violating the second law, then it's time to scrap that proposition and propose something else.