How certain is entropy?

>>7835509
Entropy is not solid at all its just like quantum mechanics as its a great model as far as the math goes and accurately predicts the real world but it makes no sense from a cause and effect standpoint

>>7835518
But then if it's so vague, why don't we have a lot of technologies supposedly ruled out by entropy?
For example, simultaneously lighting and cooling something by having electrons go up energy levels from infrared absorbtion then drop to their lowest energy level again emitting a visible photon in the process.

>>7835522
Laser cooling exists

Entropy is empirical. Theoretically there's no reason why something couldn't reorganize itself or time move in opposite direction. It just doesn't happen

>>7835509
>>7835509
What are any observed violations of the law of entropy?

>>7835530
Laser cooling doesn't violate entropy, and is entirely unrelated although pretty cool.

>>7835531
I know of none.

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>>7835530
Hey, one thing that confuses me about laser cooling...
This part of the Wikipedia article.
If there is no net change in momentum of the atom over time, how does cooling occur?

>>7835539
The laser incoming is preferantially absorbed from a specific direction. But it is emitted in a random direction. Overall this produces a reduction in momentum.

Please consider changing your major to gender studies or african american studies - you may be able to cope better intellectually with them. Clearly physics is beyond you.

>>7835556
That's a silly explanation, you just said what the Wikipedia article said as if it would clarify.
Although I just suddenly realised why it does work, right... I forgot that the atom would have no net change in momentum for a single emission if it emitted the photon so that it kept going in the direction it was going when absorbed, and all other emission directions would slow the atom down.

Also, I never knew there were such things as African American studies. Seeing a white guy in one would be funny.

Imagine a particle called a Mootron. When two Mootrons collide, they form a particle called Fred, conserving the same energy and momentum. Entropy decreased.
Also imagine that Mootrons are blue, and Fred is a talking beaver. Imagination is fun.

>>7835565
Is pretty common to see the whites, gays,feminazi in these classes because a braindead 9 y.o with downs could pass the classes.

I took an upper level class in gender studies. Showed up for tests. 3 hour final took 15 minutes. Didn't read at all. Made up b.s. about white male guilt and how were all special snowflakes.

>>7835565
My older sister took African studies, and she's not a SJW.
Idk why.

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>>7836087
>African studies:
Looks critically at African history, nation building, language standardization, the transformation of colonial states into puppet states, the anatomy of a dictatorship and hundreds of other complex, fascinating topics.

>African-American studies
An unstoppable sperg machine shouting "We are relevant to American culture! Muh Equiano! Muh Booker T!"

One of these things is a worthy field of study, the other is SJW fodder.

>>7836122
African studies actually sounds really interesting.
I'd consider taking them, except I'd be surprised if my university does them and I wouldn't have the time anyway.
I do have a vested interest in such a topic, one day I want to use the poverty of Africa to be able to mass-employ to do landscaping to make large areas of land more habitable, creating some sort of mini-state that's still legally part of the surrounding territory although completely different and with me dominating financially.

We've kinda gotten derailed though.

>>7835518
>but it makes no sense from a cause and effect standpoint

No, the action of entropy is just the tendency for likely things to happen. 7 is a more likely roll of two dice than 11, because there are more ways for two dice to make 7 than 11. It also has higher entropy for the same reason. Ain't mysterious.

>>7836551
But I've heard entropy explained as "the more free energy there is in the universe, the less entropy there is, and there is no way to lower the total entropy in the universe"; with free energy meaning any energy that can cause something to happen. e.g. hot water and cold water can create convection and thus has free energy, but warm water although it contains energy has no free energy when isolated.

>>7836968
That's because motion on quantum level is probabilistic

Both explanations are compatible

>>7837256
Entropy seems to dominate in systems that have no probability though too.
Almost all number sequences diverge or converge for example.

>>7837267
Convergence has nothing to do with entropy

>>7836551
That would be a perfect example if it weren't for the one major difference between dice and say the positions of a group of water molecules
If you roll a one to 10^99999 the laws of physics still work but in the case of the water the laws of physics are broken (conservation of energy)

>>7835509
wan wan

>>7835509
>we say the second law of thermodynamics in inviolable
You forget one huge exception: local entropy may increase or decrease. This insight was the underlying reason why the discovery of chemical oscillators resulted in a Nobel Prize.

>>7836517
>do landscaping to make large areas of land more habitable
Not needed, there are already huge amounts of prime land waiting for someone to start farming. Namibia alone could feed the entire African continent. The problems are entirely non-technical but still very real.

>>7835556
No need to be a smarmy faggot.

>>7835577
This story is made up

>>7838291
I know that local entropy may increase or decrease, but I'm more interested in decreasing global entropy.
Interesting stuff about Namibia though. Is this one of those cases where the government gives huge freebies to goons, resulting in huge amounts of land that are unused?

>>7839206
Decreasing global entropy would appear to violate known laws of physics. Perhaps, just perhaps, a Big Crunch would reset the whole thing.

As for Namibia, the whole continent is just a collection of rivalry. State borders mean little, place grid lines for ethnicities over Africa and it looks like you put a mosquito net over it. Quite a lot of groups hate each others and a fellow student from Africa told me about it. It is politically incorrect (everything is always the fault of whites, remember?) so you never hear about it on the news. So if one group is starving to death it is perfectly fine with many of their neighbours.

Also look up a resource map of Africa: you will find the continent has everything, except from functioning infrastructure and industry, of course. It is interesting to see how China handles this.

>>7839269
>decreasing global entropy would appear to violate known laws of physics
That's the point of this thread, that decreasing global entropy does violate laws of physics in the most obvious cases but it may be that the laws being violated have nothing to do with entropy(entropy decrease usually means a potential energy increase), and so a more subtle case where a decrease in global entropy does not violate the law of conservation of energy may be perfectly valid.

The only example though I can think of where entropy decreases but energy definitely doesn't change one jot is having two photons interact with an electron simultaneously and cause that electron to spit them out as a single higher energy photon.

>>7839206
this happens naturally over very long periods of time if man isnt fucking things up. (think of oil and coal building up geologically. top soils getting deeper due to natural processes. also metal rich volcanic intrusions form naturally.)

but the increase in entropy of the sun more than makes up for local decreases.

>>7839323
That's because our laws of entropy work very well on a large scale.
This topic is about whether or not singular interactions on the very small scale must not be able to decrease global entropy, because if they were able to decrease global entropy then one could presumably make a device that decreases its own entropy (expelling heat as light for example) at no cost to global entropy.

>>7839348
youre talking about perpetual motion machines...

>>7839453
A classical perpetual motion machine is obviously invalid because a portion of motion is converted to waste heat and so if it can move forever it generates infinite energy.

A perpetual motion machine that converts waste heat to motion is entirely valid if you've got a means of violating entropy.

>>7835509
If we could create a machine such that it could cause a universe wide decrease in entropy, such as a heat pump which takes heat from a cold reservoir and transfer it to a hot one without energy input, we could then couple it with a good old heat engine and create a perpetual motion machine. This is contradictory to our observation of the universe. I know it's not satisfying, but some things in physics have to be a posteriori.

As for why could a system not spontaneously reorganize itself to have lower entropy without violating these laws through quantum shenanigans, I don't think anyone has an answer, but perhaps that is the mechanism which creates something out of nothing, anon. Remember, nothing is real.

>>7839548
Mind actually reading the OP?
I explicitly say something along the lines of "entropy violation may be possible as long as it creates no potential energy".
Taking heat from a cold resevoir and transferring it to a hot one creates potential energy.

Having something convert heat into light creates no potential energy yet is still a violation of entropy, this is the kind of scenario I'm talking about.