What is entropy? A measure of just how little we know
quantamagazine.org
What is entropy? A measure of just how little we know
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Re: What is entropy? A measure of just how little we know
#2> As physicists have worked to unite seemingly disparate fields over the past century, they have cast entropy in a new light — turning the microscope back on the seer and shifting the notion of disorder to one of ignorance. Entropy is seen not as a property intrinsic to a system but as one that’s relative to an observer who interacts with that system.
Maybe I have the benefit of giant shoulders, but this seems like a fairly mundane observation. High-entropy states are those macrostates which have many corresponding microstates. The classification of several microstates into the same macrostate, is this not a distinctly observer-centred function?
I.e. if I consider 5 or 6 to be essentially the same outcome of the die, then that will be a more probable (higher-entropy) outcome. But that's just due to my classification, not inherent to the system!
Re: What is entropy? A measure of just how little we know
#3http://www.thelastquestion.net/ - in case someone missed it somehow
Re: What is entropy? A measure of just how little we know
#4Entropy, a measure of freedom in a contained environment.
Re: What is entropy? A measure of just how little we know
#5> As physicists have worked to unite seemingly disparate fields over the past century, they have cast entropy in a new light — turning the microscope back on the seer and shifting the notion of disorder to one of ignorance. Entropy is seen not as a property intrinsic to a system but as one that’s relative to an observer who interacts with that system. Maybe I have the benefit of giant shoulders, but this seems like a…
In physics the requirement for a valid changing the frame of reference is, that the laws of physics transform according to the transformation.
Every observer should discover the same fundamental laws when performing experiments and using the scientific method.
To stay in your analogy, saying 5 and 6 are the same would only work if the rules of the game you play could transform in such a way that an observer making a distinction between the two would arrive at the correctly transformed rules in his frame of reference.
Given that we have things like neutron stars, black holes and other objects that are at the same time objects of quantum physics and general relativity, the statement feels pretty fundamental to me, to a degree even that I wonder if it might be phrased to strongly.
Re: What is entropy? A measure of just how little we know
#6http://www.thelastquestion.net/ - in case someone missed it somehow
Wow.
When did we take the turn from sci-fi like that to the ever dystopian laments we read today.
Re: What is entropy? A measure of just how little we know
#7http://www.thelastquestion.net/ - in case someone missed it somehow
This is my favorite Isaac Asimov story and the reason I started reading him.
Re: What is entropy? A measure of just how little we know
#8> As physicists have worked to unite seemingly disparate fields over the past century, they have cast entropy in a new light — turning the microscope back on the seer and shifting the notion of disorder to one of ignorance. Entropy is seen not as a property intrinsic to a system but as one that’s relative to an observer who interacts with that system. Maybe I have the benefit of giant shoulders, but this seems like a…
> mundane observation
What makes an observation mundane? I think what you said is insightful and demonstrates intelligence. I don't think it's at all obvious to the masses of students that have poured over introductory physics textbooks. In fact, it seems to me that often entropy is taught poorly and that very few people understood it well but that we are beginning to correct that. I point to the heaps of popsci magazines, documentaries and YouTube videos failing to do anything but confuse the public as additional evidence.
Re: What is entropy? A measure of just how little we know
#9> As physicists have worked to unite seemingly disparate fields over the past century, they have cast entropy in a new light — turning the microscope back on the seer and shifting the notion of disorder to one of ignorance. Entropy is seen not as a property intrinsic to a system but as one that’s relative to an observer who interacts with that system. Maybe I have the benefit of giant shoulders, but this seems like a…
In physics the requirement for a valid changing the frame of reference is, that the laws of physics transform according to the transformation. Every observer should discover the same fundamental laws when performing experiments and using the scientific method. To stay in your analogy, saying 5 and 6 are the same would only work if the rules of the game you play could transform in such a way that an observer making a…
I think you may have misunderstood the OP's point - the entropy you calculate for a system depends on how you factor the system into micro and macro states. This doesn't really have anything to do with changes of reference frame - in practice it's more about limitations on the kinds of measurements you can make of the system.
(you can't measure the individual states of all the particles in a body of gas, for instance, so you factor it into macrostate variables like pressure/temperature/volume and such)
Re: What is entropy? A measure of just how little we know
#10A related thread from earlier this year,
https://news.ycombinator.com/item?id=41037981 ("What Is Entropy? (johncarlosbaez.wordpress.com)", 209 comments)