Entropy should be redefined as “the distribution of potential over negative potential.”
Whether discussing what is over what may be, or thermal equilibrium, potential distribution describes it all!
Entropy: A little understood concept in physics [video]
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Re: Entropy: A little understood concept in physics [video]
#32I think the concept would be easier for me to understand if we talked about the inverse of entropy - i.e. some kind of measurement for the concentration of useful energy or "order". I think it would then be more intuitive to say that this measurement always decreases. Do we even have a word for the opposite of entropy?
Negentropy? This is a concept in information theory, but maybe also in physics.
Re: Entropy: A little understood concept in physics [video]
#33I think the concept would be easier for me to understand if we talked about the inverse of entropy - i.e. some kind of measurement for the concentration of useful energy or "order". I think it would then be more intuitive to say that this measurement always decreases. Do we even have a word for the opposite of entropy?
I find it intuitive to think of such “ordered” distributions as having a higher compression ratio. (Ie compare the file sizes of zipping a file with just ones or just zeros vs zipping a file with a uniform, random mixture of ones and zeros.)
Re: Entropy: A little understood concept in physics [video]
#34I think the concept would be easier for me to understand if we talked about the inverse of entropy - i.e. some kind of measurement for the concentration of useful energy or "order". I think it would then be more intuitive to say that this measurement always decreases. Do we even have a word for the opposite of entropy?
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Re: Entropy: A little understood concept in physics [video]
#35Earlier quoted context omitted.
Not really - look up “heat death” of the universe.
Heat death doesn’t mean “no heat” or that energy has depleted. It just means that energy is fully dispersed. All kg the hear exists, it’s just that no one place has any more than anywhere else, and so there is no longer any transfer of energy.
> so there is no longer any transfer of energy.
Ah, but there is.
The Second Law is a statistical law, not an absolute law. On long enough timescales, low-probability fluctuations in local entropy will allow for energy transfer. These fluctuations will also allow for the formation of structures. (Boltzmann himself was of the opinion that the low-entropy universe emerged from a higher-entropy background state. And indeed there's nothing in physics to rule out the emergence of Boltzmann Brains and even Boltzmann Galaxies from homogeneous and maximally entropic universes in "heat death." This is a philosophical problem of the highest order, because it implies that we're not necessarily going from "less likely to more likely states" as the video implies, but rather from a relatively deterministic state to a probabilistic state.)
Re: Entropy: A little understood concept in physics [video]
#36That's an excellent overall summary as he covers almost every aspect of the subject albeit in brief. It would be good if he produced a second video dealing with the low entropy of incoming energy from the sun and the higher entropy of radiated energy from earth and relate that to global warming. In all the debate over global warming little is talked about why say CO2 and other greenhouse gasses increase the earth's t…
The important part to understand is timescales. In a day, the Earth does absorb some energy. Of course it does, plants collect it, solar panels collect, the ocean and land collect it. The amount Earth collects is a tiny fraction of what it releases. That collection isn’t permanent though and is slowly released. Within a day, the Earth absorbs some energy, but over a long enough timescale, all of that energy is released again.
The Earth is taking on energy every day from the sun. If we didn’t release it all back, the earth would be warming much much faster. It only remains relatively cool because it releases almost as much as it receives.
Another important note is that long term energy is not only stored as heat on earth. It’s stored as potential energy in the atoms of cells in plants and animals. Think of how cold a gallon of gasoline is, yet how much energy it stores.
For an example think of hot asphalt from a summer day. It gets real hot all day and slowly cools down at night. Sometimes it can be pretty warm to stand on the road even if it’s a cool night.
Within the human timescale, the Earth is retaining some (tiny fraction) of heat. That tiny fraction of heat is a very small window of heat that life can tolerate. It’s not too much and not too little. If the earth were to retain just a tiny bit more, suddenly life can’t tolerate it. On the scale of the universe, the difference between those realities is minuscule, even though it’s enormous to us.
Re: Entropy: A little understood concept in physics [video]
#37I’d like to think of entropy in terms of randomness or rather uniqueness of elements/compounds within a system.
Re: Entropy: A little understood concept in physics [video]
#38Entropy only made sense when I learned it from the perspective of statistical thermodynamics. It's a very programmerly understanding, IMHO, and it's quite intuitive. EXCEPT that the language used is ridiculous: grand canonical ensemble indeed! Anyway, the idea that a system can be in some number of specific states, and that equilibrium is that unique situation where the number of possible specific states is at its maximum, really spoke to me.
Re: Entropy: A little understood concept in physics [video]
#39I think the concept would be easier for me to understand if we talked about the inverse of entropy - i.e. some kind of measurement for the concentration of useful energy or "order". I think it would then be more intuitive to say that this measurement always decreases. Do we even have a word for the opposite of entropy?
> Do we even have a word for the opposite of entropy?
I've always referred to the inverse as "information" or "order".
Re: Entropy: A little understood concept in physics [video]
#40Earlier quoted context omitted.
Heat death doesn’t mean “no heat” or that energy has depleted. It just means that energy is fully dispersed. All kg the hear exists, it’s just that no one place has any more than anywhere else, and so there is no longer any transfer of energy.
> so there is no longer any transfer of energy. Ah, but there is. The Second Law is a statistical law, not an absolute law. On long enough timescales, low-probability fluctuations in local entropy will allow for energy transfer. These fluctuations will also allow for the formation of structures. (Boltzmann himself was of the opinion that the low-entropy universe emerged from a higher-entropy background state. And ind…
Oh interesting, I didn’t know that