Because photons have zero mass.memento said:Hello everyone, I have heard in a sminar that radiation is the highest form of entropy. Why?
Entanglement is related to the conservation of energy, momentum, and angular momentum. For example, if a radiated photon has certain energy ##E##, then the source must have energy reduced by the value ##-E##. This means that their energies are correlated. For quantum systems, the correlation is described by entanglement.memento said:Thank you. Do you know how is the entropy involved in combustion (the heat emited in form of radiation)? More exactly, why are the photons entangled in this procces?
You can't say this in general. For example, laser radiation has very little entropy.memento said:Hello everyone, I have heard in a sminar that radiation is the highest form of entropy. Why?
I was wondering too if all matter would transform at the end in radiation somehow
Of course, but in this thread it was implicit that it is about thermal radiaton.DrDu said:You can't say this in general. For example, laser radiation has very little entropy.
Demystifier said:Entanglement is related to the conservation of energy, momentum, and angular momentum. For example, if a radiated photon has certain energy ##E##, then the source must have energy reduced by the value ##-E##. This means that their energies are correlated. For quantum systems, the correlation is described by entanglement.
Is your question motivated by a desire to understand radiation by black holes?
We do see it, but it is perhaps not so obvious because the process of mass reduction is usually quite slow.memento said:conversion of mass into light is spontaneus, why don´t we see it?
This is a misunderstanding. Entropy is not conserved in Nature.memento said:the conservation of information in quantum mechanics
is something completely classical, unrelated to entanglement.memento said:the heat emited in form of radiation
This is impossible since baryon number is conserved.memento said:if all matter would transform at the end in radiation somehow
This is both true and wrong, depending on the precise definition of entropy.A. Neumaier said:Entropy is not conserved in Nature.
But post #1 makes sense only in the context of macroscopic (hence coarse-grained), increasing entropy. (Even then only superficially, since it ignores conservation laws that are actually valid.)Demystifier said:fine grained Gibbs entropy is conserved
A. Neumaier said:This is a misunderstanding. Entropy is not conserved in Nature.
You can neither destroy the information, nor create it, I think entropy reflects the state of this information.
I agree. But to understand how can it be compatible with conservation of information in QM, one has to have in mind the existence of different kinds of entropy.A. Neumaier said:But post #1 makes sense only in the context of macroscopic (hence coarse-grained), increasing entropy.
Demystifier said:We do see it, but it is perhaps not so obvious because the process of mass reduction is usually quite slow.
DrDu said:There are also conservation laws for charge, baryonic number etc. which don't allow for the conversion of mass into light.
I'll not give you a formula, but a physical idea. The Sun needs a few billion years to convert a significant fraction of its initial mass into light.memento said:Really? Could you give me more information about the velocity of this process, a formula would be nice, thank you
Before judging, I would propose at least to wait whether this prophecy becomes reality. Btw. from whom is this announcement?memento said:I supposse this conservation law don´t allow convert light into matter, but this is FALSE, since in 2014 was announced that this year we will see it!
memento said:Hello everyone, I have heard in a seminar that radiation is the highest form of entropy. Why?
I was wondering too if all matter would transform at the end in radiation somehow
DrDu said:Before judging, I would propose at least to wait whether this prophecy becomes reality. Btw. from whom is this announcement?
Demystifier said:I'll not give you a formula, but a physical idea. The Sun needs a few billion years to convert a significant fraction of its initial mass into light.
Well, if nuclear reactions were the only kind of reaction, you would be right. But there are also other forces, much weaker and therefore much slower, due to which even iron-56 may not be stable at much longer time scales.memento said:Beacuse of this, the end of the universe cannot be to convert all the matter into light, because fission is spontaneous for heavy nuclei.
Demystifier said:Well, if nuclear reactions were the only kind of reaction, you would be right. But there are also other forces, much weaker and therefore much slower, due to which even iron-56 may not be stable at much longer time scales.
For more details about the appropriate time scales see
https://en.wikipedia.org/wiki/Timel...he_Earth.2C_the_Solar_System_and_the_Universe
In particular, iron-56 is at ##10^{1500}##, but that's not the end.
Radiation is considered the highest form of entropy because it involves the transfer of energy from one place to another, resulting in a decrease in the amount of available energy. This decrease in available energy corresponds to an increase in disorder, or entropy, which is a measure of the randomness or chaos in a system. The more energy that is transferred, the greater the increase in entropy, making radiation the highest form of entropy.
Radiation leads to an increase in entropy because it involves the transfer of energy from a concentrated source to a more dispersed form, such as heat or light. This transfer of energy results in a decrease in the amount of available energy, increasing the disorder and randomness in the system. As a result, the overall entropy of the system increases.
No, radiation is not the only form of entropy. Entropy can also be increased through other processes, such as chemical reactions, diffusion, and mixing. However, radiation is often considered the highest form of entropy because it involves the transfer of energy on a larger scale and can have a more significant impact on the overall disorder of a system.
The second law of thermodynamics states that the total entropy of a closed system will always increase over time. This means that the disorder or randomness in a system will continually increase until it reaches a state of maximum entropy. Radiation is one way in which this increase in entropy occurs, as it involves the transfer of energy and a decrease in the amount of available energy in a system.
Yes, it is possible to control radiation in order to decrease entropy in a system. This can be achieved through processes such as insulation, which helps to minimize the transfer of energy, or using devices such as refrigerators or air conditioners, which use energy to decrease the entropy of a specific space. However, these methods do not eliminate entropy entirely, as the second law of thermodynamics dictates that entropy will always increase over time.