Entropy is pretty abstract and mind boggling.
However using this kind of diagram one can see a pragmatic use of it and get some feel about it.
This is far from the statistical approach.
These diagrams are used to design and optimize machines, like steam turbine engines, refrigerators, jet engines, heat pumps.
It is close to the dS = dQ / T definition.
https://en.wikipedia.org/wiki/Temperature–entropy_diagram
Enjoy.
However using this kind of diagram one can see a pragmatic use of it and get some feel about it.
This is far from the statistical approach.
These diagrams are used to design and optimize machines, like steam turbine engines, refrigerators, jet engines, heat pumps.
It is close to the dS = dQ / T definition.
https://en.wikipedia.org/wiki/Temperature–entropy_diagram
Enjoy.
The new Event Horizon Telescope image of Sagittarious A* has been compared with a library of 5 million computer simulated images of black holes.
These images take into account variables such as spin rate, magnetic field strength, warping of spacetime, turbulance in the accretion disc, etc..
The comparison has revealed some interesting information about the supermassive black hole at the centre of our galaxy:
These images take into account variables such as spin rate, magnetic field strength, warping of spacetime, turbulance in the accretion disc, etc..
The comparison has revealed some interesting information about the supermassive black hole at the centre of our galaxy:
- The activity in its accretion disc (revealed by those variable bright regions) is less than the simulations predicted.
- Its magnetic field is no stronger than that of a fridge magnet (but strong enough to prevent some gas from falling into the black hole).
- It is probably spinning (there are no direct measurements, but simulations where it did not spin were ruled out).
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TBH, I thought that alleged Image of Sagittarius "A" by an enormous team of 300 Astrophysicists was a bit blurry! Even my putrid solo efforts with my Canon Coolpix camera are usually sharper than that! What is it supposed to be? A 3-sided doughnut? At a stretch, an alternating hexagon? 
Clearly Phase Information was lost in combining the multiple snaps.
My current obsession is Quantum Gravity. How hard can it be? I am fed up with the Standard Model and String Theory. Am reading Carlo Ravelli "Reality is not what it seems: The Journey to Quantum Gravity". Excellent tome.
We are talking Lee Smolin's "Quantum Loop Gravity".
All the usual Physics visionaries pop up. Copernicus, Kepler, Galileo, Newton, Einstein, Feynman. Honourable mentions for Michael Faraday and James Clerk Maxwell too in electromagnetic Fields. Conformal Field Theory being a little favourite of mine.
Strangely most of what we are doing now was all clear as Day to the Ancient Greeks. Not many people know this.
Democritus was the top man back in the day around 460BC.
https://en.wikipedia.org/wiki/Democritus
So good, they burnt all his books. But some quotes survive by Roman authors.
The lost books are a huge loss. This is the man who discovered the atom by pure logic. Discovered Brownian motion in flecks of dust suspended in sunlight, which Einstein rediscovered after a waste of 2,500 years. Embarrasiing stupidity, IMO.
https://en.wikipedia.org/wiki/Democritus#Works
I am fairly comfortable with Shannon Entropy. Log base 2 an' all that. A Dolphin, which some argue is a more Intelligent species than us, being naturally accustomed to Fluid motion, would naturally work in base 2, having 2 flippers, rather than our simian 10 digits. Not going to spend much more time on it. Bigger, er, fish to fry!
Clearly Phase Information was lost in combining the multiple snaps.
My current obsession is Quantum Gravity. How hard can it be? I am fed up with the Standard Model and String Theory. Am reading Carlo Ravelli "Reality is not what it seems: The Journey to Quantum Gravity". Excellent tome.
We are talking Lee Smolin's "Quantum Loop Gravity".
All the usual Physics visionaries pop up. Copernicus, Kepler, Galileo, Newton, Einstein, Feynman. Honourable mentions for Michael Faraday and James Clerk Maxwell too in electromagnetic Fields. Conformal Field Theory being a little favourite of mine.
Strangely most of what we are doing now was all clear as Day to the Ancient Greeks. Not many people know this.
Democritus was the top man back in the day around 460BC.
https://en.wikipedia.org/wiki/Democritus
So good, they burnt all his books. But some quotes survive by Roman authors.
The lost books are a huge loss. This is the man who discovered the atom by pure logic. Discovered Brownian motion in flecks of dust suspended in sunlight, which Einstein rediscovered after a waste of 2,500 years. Embarrasiing stupidity, IMO.
https://en.wikipedia.org/wiki/Democritus#Works
I am fairly comfortable with Shannon Entropy. Log base 2 an' all that. A Dolphin, which some argue is a more Intelligent species than us, being naturally accustomed to Fluid motion, would naturally work in base 2, having 2 flippers, rather than our simian 10 digits. Not going to spend much more time on it. Bigger, er, fish to fry!
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And there was I, thinking that Brownian Motion was discovered by Scottish botanist Robert Brown in 1887, then theorised by Einstein in 1905!
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Researching:
Democritus held that matter was composed of minute particles. He also maintained that these particles were in a state of continuous random motion within solids, liquids and gases.
It was not until 1827, however, that actual experimental evidence for these particles existed. This was provided by the Scottish botanist Robert Brown.
Democritus held that matter was composed of minute particles. He also maintained that these particles were in a state of continuous random motion within solids, liquids and gases.
It was not until 1827, however, that actual experimental evidence for these particles existed. This was provided by the Scottish botanist Robert Brown.
Trouble is the flecks of dust are not atoms.
They are large aggregates of molecules.
Furthermore, the Brownian look behavior is not from interactions of flecks. It has more to do with the air moving.
This analogy is fake or related through convoluted explanations.
At best, looking at the flecks moves can stimulate imagination to inventing the Brownian bit.
Italians would say. "Se non e vero e ben trovato".
They are large aggregates of molecules.
Furthermore, the Brownian look behavior is not from interactions of flecks. It has more to do with the air moving.
This analogy is fake or related through convoluted explanations.
At best, looking at the flecks moves can stimulate imagination to inventing the Brownian bit.
Italians would say. "Se non e vero e ben trovato".
The continual, random motion is due to the tiny, invisible air molecules colliding with the much larger flecks.
When more air molecules collide with one side of the fleck than with the other sides, the fleck will jerk in the direction of the resultant force.
Obviously. Even a twit such as myself has that much intuition, enter Democritus.Not saying he was a twit.
I've actually witnessed this phenomenon in wonderment.
To be clear, I was describing Brownian motion in my previous post where the "flecks" to which I referred are smoke particles suspended in the 'still' air inside a glass air cell - as in the traditional school experiment.
The movement of flecks of dust suspended in a free, mobile air stream is not Brownian motion, as mchambin has pointed out.
Yes, Brownian motion is truly a wondrous and thought invoking phenomenon to behold.
The movement of flecks of dust suspended in a free, mobile air stream is not Brownian motion, as mchambin has pointed out.
Yes, Brownian motion is truly a wondrous and thought invoking phenomenon to behold.
What I witnessed were particles suspended in still air outside while sitting on porch steps on a bright sunny morning. Perfectly calm with the sun beating down I watched them dancing around in front of me with the odd one here and there at random taking off and zig zagging a short way. At first I thought they were something alive but looking more carefully it was obvious they were far too small. The bright sunlight made them visible. I have no idea what particulate matter it was. This mention of them is the first insight I've received as to what it was. The simulation is a good approximation of the movement I saw.
So, are you saying that information entropy decreases as thermodynamic entropy increases?
It does seem that way. The future is for the most part filled with near infinite possibilities - how atoms will behave in different potential environments, how stars will develop etc. but once an event has transpired, it’s a matter of record - it is effectively frozen and our knowledge of the event is precise. It could have had any number of outcomes, but only one happened.
It does seem that way. The future is for the most part filled with near infinite possibilities - how atoms will behave in different potential environments, how stars will develop etc. but once an event has transpired, it’s a matter of record - it is effectively frozen and our knowledge of the event is precise. It could have had any number of outcomes, but only one happened.
We did the Brownian motion experiment at school using a mild solution of black watercolour pigment and water. Under the microscope you can see random paint particles zoom around as they are struck by the water molecules. We didn’t get to heat the water up, but I guess you’d see increased activity if you did.
We know entropy increases with thermal activity. It’s not a case of it exists or does not.
On the information side, I’m simply pondering the fact that it seems to decrease with time because we will know everything there is to know about all matter eventually. However, I suspect Heisenberg will have something to say about that!
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