81–90 of 298 posts
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Think minimum description length. Low entropy states require fewer terms to fully describe than high entropy states. This is an objective property of the system.
“Number of terms” is a human language construct.
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Think minimum description length. Low entropy states require fewer terms to fully describe than high entropy states. This is an objective property of the system.
You're thinking of information entropy, which is not the same concept as entropy in physics. An ice cube in a warm room can be described using a minimum description length as "ice cube in a warm room" (or a crystal structure inside a fluid space), but if you wait until the heat death of the universe, you just have "a warm room" (a smooth fluid space), which will have an even shorter mdl. Von Neuman should never have…
Because there are an infinite number of microstates (all the particles are interchangeable) that lead to the same macrostate: nothing happening for ever!
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Please communicate in full sentences with me. I can only guess that your objection is something about probabilities. A microstate has a probability independent of my knowledge of the system just like the probability of having a royal flush doesn't change after drawing five cards. The probability of me ending the game with a royal flush might, but that is not what we mean by these probabilities.
The same microstate will have different probabilities depending on what are the constraints or measurements used in _your_ description of the system. If you choose to describe the system using its microstate - and you know it - there are no probabilities anywhere. You can of course know something and choose to ignore it - the entropy is still a reflection of the uncertainty (actual or for the sake of a lower-resoluti…
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Virtual particles and related effects are actually widely accepted and experimentally proven (at least partially). Current physics wouldn't really work without them, or at least something that looks the same. https://en.wikipedia.org/wiki/Casimir_effect https://en.wikipedia.org/wiki/Zero-point_energy https://en.wikipedia.org/wiki/Virtual_particle https://en.wikipedia.org/wiki/Hawking_radiation The gist of it is, that…
The Wikipedia article that you quote is quite explicit that, while virtual particles are a widely accepted mathematical tool, they're actual existence of elements of reality is very much not widely accepted, and definitely nowhere close to "experimentally verified". It's in fact considered impossible to verify experimentally, even in principle. Note that there are many very widely used physical theories that include…
What is proven is that e.g. vacuum energy / zero point energy exists (not actually in the StarGate sense of extractable energy, just that the lowest energy state of any physical system isn't zero), and that the Casimir effect exists. Vacuum energy directly leads to virtual particles through pair production (which is a proven mechanism, at high energies, for low energies we do suspect that there isn't a cutoff there), and also influences e.g. high-energy cosmic rays leading to an observed high-energy cutoff (although there are other possible explanations for that cutoff and lack of very-high-energy cosmic rays). The Casimir effect is most easily explained by virtual particles and vaccum energy.
In Hawking radiation, the idea is actually that virtual particles through interaction with the gravity of the black hole become real particles. The event horizon actually makes those wave functions collapse such that real particles start to exist. Hawking radiation hasn't been observed yet, however.
[1] non-Kopenhagen QM has the same consequences, it's just even harder to explain actually.
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Think minimum description length. Low entropy states require fewer terms to fully describe than high entropy states. This is an objective property of the system.
You're thinking of information entropy, which is not the same concept as entropy in physics. An ice cube in a warm room can be described using a minimum description length as "ice cube in a warm room" (or a crystal structure inside a fluid space), but if you wait until the heat death of the universe, you just have "a warm room" (a smooth fluid space), which will have an even shorter mdl. Von Neuman should never have…
[1] https://en.wikipedia.org/wiki/Entropy_in_thermodynamics_and_...
We all know that life on Earth gets it's energy from the Sun. But we also know that's an approximation we tell kids, really life gets low entropy photons from the Sun, does it's thing, and then emits high entropy infrared waste heat. Energy is conserved, while entropy increases. But where did the Sun got it's low entropy photons to start with? From gravity, empty uniform space has low entropy, which got "scooped up"…
But where did the Sun got it's low entropy photons to start with? From gravity, empty uniform space has low entropy, which got "scooped up" as the Sun formed. From the Big Bang originally. We don’t know what caused the Big Bang.
"It's turtles all the way down."
"There’s some kind of gas or some thermal system out there that we can’t see directly" - The Ether is back on the menu boys
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Isn't that how equations get solved? Pretty much anything known entered through such placeholder, it's just that equations could be connected more easily. It's not like Higgs field is something you can directly observe
Maybe, (I don't know), but it's easy to accidentally come up with a theory of "mysterious stuff" that appears to explain something, but neither constrains your expectation nor provides predictions. Phlogiston is the classic example. https://www.lesswrong.com/posts/RgkqLqkg8vLhsYpfh/fake-causa...
You find some un-identified variables.
Form some hypothesis, try to narrow it down.
Sometimes it is a discovery, new particle, and sometimes it is nothing.
But that is how science works.
At some point in time, everything was an unknown, and people had to work with unknowns.
This whole movement from the 'right' that all science has to know the answers ahead of time in order to justify spending money, is hindering progress. How can you know the results are worthwhile, in order to justify funding, before doing the research to know the results?
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> there are far more ways for a system to be disordered than ordered I'm a complete layman when it comes to physics, so forgive me if this is naive — but aren't "ordered" and "disordered" concepts tied to human perception or cognition? It always seemed to me that we call something "ordered" when we can find a pattern in it, and "disordered" when we can't. Different people or cultures might be able to recognize patter…
You only hear these terms in layman explanations. Physics has precise definitions for these things. When we say "ordered", we mean that a particular macrostate has only few possible microstates. Check this Wikipedia article for a quick overview: https://en.wikipedia.org/wiki/Microstate_(statistical_mechan... Details can be found in any textbook on statistical mechanics.
If the coins were of different color and you took that into account, then it wouldn't work.
It's not intuitive to me what gravity has to do with entropy though, as it's classically just a force and completely reversible (unlike entropy)? Ie if you saw a video of undisturbed objects only affected by gravity, you couldn't tell if the video was reversed.