Timeline for Where does information go if thermodynamic death?
Current License: CC BY-SA 3.0
16 events
| when toggle format | what | by | license | comment | |
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| Feb 24, 2015 at 20:10 | comment | added | Harry Johnston | @Aron: as John said, that is still an open question. Hawking conceded the bet, but that doesn't prove anything about the actual physics, or necessarily mean that everybody else agrees. | |
| Feb 24, 2015 at 18:55 | comment | added | Criticizing Israel not allowed | @Dims AFAIK, thermodynamics is a probabilistic thing - there are very few states which will decrease in entropy if you evolve them, but the vast majority (think 99.99999% with a million 9's) won't. If you take the current state of the universe, and evolve it backwards, you will get a state with less entropy - but only because the current state is one of those rare ones that was created by evolving forwards from a low-entropy state. If you evolve any randomly chosen state backwards, you won't decrease entropy (with more certainty than the Earth not suddenly exploding). | |
| Feb 24, 2015 at 13:50 | comment | added | Aron | @JohnRennie okay..black hole evaporation. There was a very famous bet between a Steven Hawking and Kip Thorn on this very matter. The result was Kip won, and information does indeed leak out of a black hole. Also information loss IS entropy increasing. | |
| Feb 24, 2015 at 11:34 | comment | added | John Rennie | @Aron: OK, but the point is that if the system involves black hole evaporation the process is fundamentally irreversible regardless of whatever the circumstances. That is the point of the question, and that's the question I answered. | |
| Feb 24, 2015 at 11:27 | comment | added | Aron | The point is that each reversible reaction yields more information. That information is the step to reverse that reaction. Thus as long as you keep all the information you can recombine it in reverse with the system to yield the original state. Its a bit of a cop out...the reaction is reversible until you lose the thing to reverse it... | |
| Feb 24, 2015 at 11:20 | comment | added | Aron | @lemon not with infinite (or enough) informational storage. The difference is important in a question on entropy and information theory. | |
| Feb 24, 2015 at 11:20 | comment | added | John Rennie | Increasing entropy <> information loss. You get back the egg trajectory by measuring the positions and velocities of all the air molecules and tracing them back to when they hit the egg and transferred momentum to it. Obviously impractible, but doable in principle. | |
| Feb 24, 2015 at 11:19 | comment | added | lemon | @Aron I don't see how your comment contradicts what I said. At worst I was unclear with the word 'system', but I am correct that more heat is expended in restoring the 'cooled teapot' back to its warmer state. | |
| Feb 24, 2015 at 11:18 | comment | added | Aron | Information IS lost. That is how we know we are going forward in time. Entropy increases. For example.. Your egg. How do you de-evolve the system to give you the height at which it fell? What if the egg reached terminal velocity during its decent? Your answer is patently false. | |
| Feb 24, 2015 at 11:12 | comment | added | John Rennie | @Aron: just out of curiousity, why did you downvote my answer? You object to Lemon's comment, but what has that to do with my answer? I think Dim's comment about the second law is a good one, but this is being dealt with in a separate question. | |
| Feb 24, 2015 at 11:04 | comment | added | Aron | @lemon I disagree with your analysis. The point of Maxwell's Daemon is that it can reverse a system, simply by opening and closing a door. The informational analysis of Maxwell's Daemon is that as the system evolves, more information needs to be stored, until eventually, Maxwell's Daemon must delete information (assuming finite information storage). The process of informational deletion is synonymous to increase of entropy and the arrow of time. | |
| Feb 24, 2015 at 9:46 | comment | added | Dims | Still not clear for me, but the answer is probably correct. | |
| Feb 24, 2015 at 9:44 | vote | accept | Dims | ||
| Feb 24, 2015 at 9:31 | comment | added | lemon | @Dims Yes but you would have to put even more heat into the system to restore the original state, so the laws of thermodynamics would not be violated. | |
| Feb 24, 2015 at 9:26 | comment | added | Dims | What about thermodynamics law? The same reasoning can be applied to violate it: if I have cooled teapot, I can trace molecules movements back and reverse heat it (with the help om Maxwell Daemon, of course). I.e. collect heat back again. | |
| Feb 24, 2015 at 9:03 | history | answered | John Rennie | CC BY-SA 3.0 |