31–40 of 142 posts
Earlier quoted context omitted.
I don't like that definition. I like to consider ∆S the result of a smoothing operation over energy differentials. You can put work into a system to reestablish an energy differential. It just necessitates obtaining that other energy differential with which to do the work.
> I don't like that definition. Yeah, but physics aren't a la carte. Either prove it wrong (and get a nobel) or accept it.
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>> Entropy = the inverse of available energy to do anything at all. > I don't like that definition. Physics isn't a popularity contest. http://en.wikipedia.org/wiki/Entropy > You can put work into a system to reestablish an energy differential. Yes, but that doesn't change the definition of entropy -- it just borrows energy from somewhere else.
I feel like you're being that guy . Forgive me if I come across the same way. Why link me to the Wikipedia article or insinuate I'm pulling this out of--to put it more politely--ex culo? Given my use of notation, one might assume I am at least a little familiar with how the thermodynamic entropy functions are mathematically derived. To be pedantic for a bit, Entropy is an abstract mathematical state function useful f…
What's my incentive to continue a discussion with someone who has abandoned the topic? In a closed system, the amount of exploitable energy, and the quantity called entropy, move in opposite directions.
> ... or insinuate I'm pulling this out of--to put it more politely--ex culo?
Point to where I said this. If you can't, then you have abandoned the topic.
> Much like the Gibbs and Helmholtz terms, entropy has no direct qualitative basis; there are many open-ended interpretations seeking to justify what it means, which is not unlike looking for God or faeries or what have you.
Nonsense. Entropy is clearly understood, it's not a philosophical puzzle as you suggest. It's easily quantifiable. It's science, not philosophy.
> Given my use of notation, one might assume I am at least a little familiar with how the thermodynamic entropy functions are mathematically derived.
Anyone can adopt the notations used in science. This doesn't tell me anything about their knowledge of the topics under discussion. You simultaneously apply standard terminology, but you go on to say that explaining entropy is "not unlike looking for God or faeries or what have you", which means you don't understand the significance of the symbols you used.
Entropy = k log(n)
k = Boltzmann's constant.
n = number of states the system can be in.
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/temper2.ht...
Quote: "Temperature is expressed as the inverse of the rate of change of entropy with internal energy, with volume V and number of particles N held constant. This is certainly not as intuitive as molecular kinetic energy, but in thermodynamic applications it is more reliable and more general."
I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.
Yes. Open minded comments like this, questioning the limits of science get down voted here on HN.
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If the available energy is dispersed and chaotic, we won't be able to concentrate enough to perform the experiments? Though I doubt that'll be the case at any time while the human race is in existence... (caveat: I know very little of real physics)
You should first worry about how we get out of this planet before the Sun turns into a red giant and swallows the Earth after 5–6 billion years from now.
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> But if you travel at the 0.8x the speed of light and you throw something forward at 0.3x the speed of light, its speed is not 1.1x the speed of light, but c. Not really. Velocities near c don't sum that way. And your reference doesn't support your claim.
I agree. More details: http://en.wikipedia.org/wiki/Velocity-addition_formula If you add two velocities that are less than c, you can never get c, you always get something smaller. 0.8c + 0.3 c ~= 0.887 c (It's smaller than c) At low speeds the effect still exists, but it's negligible. There is an important difference between "it doesn't exist" and "it's so small that if we forget it we will be fine". It's so small t…
Indeed it is. The only place I can think where such a small correction matters is in the GPS system. The accuracy of the GPS system depends on tracking down and eliminating every possible source of error, and to maximize position accuracy, two relativistic effects are accounted for:
1. The time dilation caused by the satellites' velocity, from Special Relativity.
2. The rate of time passage at orbital altitude compared to that at the surface, which reflects the gravitational well effect of General Relativity.
The two effects move in opposite directions, but they don't cancel out. The applied correction (to the orbiting clocks) is very small indeed, but enough to avoid a gradual but serious decline in positional accuracy over time.
Earlier quoted context omitted.
If the available energy is dispersed and chaotic, we won't be able to concentrate enough to perform the experiments? Though I doubt that'll be the case at any time while the human race is in existence... (caveat: I know very little of real physics)
If humanity lives to a point where entropy becomes a problem, I'm pretty sure our lives would be the first to go, not our "ability to perform experiments".
If we were approaching any "universal energy" limitations, it'd stand to reason that our technology would be very much different than our technology now -- perhaps universe sized experiments would be feasible by that point, at which time we may hit a limit imposed on us not by anything other than the length of time since the last universe formation event, and our poor luck in meeting that point in technology at a time where the energy no longer exists to fuel it.
Unlikely, and I think your idea of life being threatened before science is probably much more rational, but it's fun to think about. Plus, if we were using that much energy for a single experiment, one would wonder about that experiments' safety.
I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.
I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.
"There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable." – from The Restaurant at the end of the Universe.
Earlier quoted context omitted.
You should first worry about how we get out of this planet before the Sun turns into a red giant and swallows the Earth after 5–6 billion years from now.
Please have some perspective. Human beings have existed in roughly our present form for 200,000 years. In another 200,000 years, chances are we won't recognize ourselves. And in 5 billion years, which is 25,000 times farther into the future, there will be nothing remotely resembling human beings . We won't be a distant memory, we won't be a memory at all.
Of course, what you say is even more immediate.
I wonder if it's possible to ever find out what our reality is even if we will eventually reach the intellectual and technology necessary because we are part of it and it's probably impossible to have an objective view of the matter.