Energy controls over everything that occurs in infinite space and in the course of transient time. Energy like a queen or goddess, who irradiates the light over everything from a blade of grass in the field of human, giving and taking here and there, while remaining constant in quantity. Yes, where there is light, there is a shade. Entropy is the name of the queen’s shadow. Face to face with this phenomenon, the human cannot help feeling some vague fear: Entropy, like an evil spirit, tries to diminish the best creations of that gracious spirit, Energy.
As per the second law of thermodynamics, it is a measure of disorder. It affects all aspects of our daily lives and in fact, we can say that it is Nature’s Tax. Many people take entropy as a part of energy. No, Entropy is not energy; Entropy is how the energy in the universe is distributed. Entropy is just another word for waste energy or energy which is not useful. It is the amount of energy that is lost to the surrounding at a specific temperature.
In other words, I can say that whatever you do, heat is released in the surrounding which increases the entropy. Let me explain with an example: Suppose You are watching a movie; you can easily determine whether it is played forward or in reverse. When run in reverse, shattered things spontaneously rebuild; smoke goes down into chimney; and ice “unmelts”, warming the environment. No physical laws are broken in this reverse movie except the ‘Second law of thermodynamics, which reflects the time-asymmetry of entropy. The second law of thermodynamics states that the state of entropy of the entire universe always increases over time. When a law of physics applies equally when time is reversed, it is said to show the time-reversal symmetry. In this case, entropy is what allows one to decide if the video is playing forward or in reverse as intuitively, we identify that only when played forwards the entropy of the scene is increasing because of the second law of thermodynamics.
The Discovery of Entropy
The term ‘Entropy’ was discovered by the German physicist Rudolf Clausius from a Greek word that means ‘a turning’ point. The word reveals that it is the form of energy that any energy eventually and inevitably turns into – a useless heat. The idea was inspired by an engineer Said Carnot, of what is now known as the Second law of thermodynamics.
Clausius studied the conversion of heat into work and gave the statement of the second law of thermodynamics “Heat doesn’t pass from a body at low temperature to a higher temperature itself without doing external work.” Clausius also observed that only a percentage of the energy was converted into actual work. Then what happens to the rest of the energy? He solved the problem and encapsulated the concept of entropy in easy terms – The energy of the universe is constant, and the entropy of the universe tends to a maximum.
Entropy and Time
Entropy is one of the few concepts that provide evidence for the existence of time. The “Arrow of Time” is a name given to the idea that time is asymmetrical and flows in only one direction: forward. It is the non-reversible process wherein entropy increases.
Doesn’t it take Energy to Change Entropy
No. The entropy can change without any change in the energy. Let’s take an example: You have a sealed box that is isolated from the rest of the universe so that no energy can go in or out of the box. Now suppose, your box has 2 parts which split it in half, the left half has 1 mole of gas, and the other half is empty or vacuum. If you remove the divider, the gas-particle will spread out so that they equally fill the whole box. The gas spread out because the entropy of having the gas particles spread through the whole box was greater than the entropy of having the gas particles stay on the left side. Thus, in this case, the entropy has increased but the energy in the box is constant.
Entropy exists Everywhere
All of us observed entropy in our daily life. Entropy is an important model which applies to every part of life. Does it appear to be pointless? Imagine a world without entropy – Everything remains exactly as we left it; no one becomes ill, nothing breaks, and nothing is damaged. Then there would also be a world without any creativity or innovation, a world without any need for progress. Many people make their efforts to reduce disorders, create new technology, work to improve lifestyle, pursue other noble goals. The existence of entropy is what keeps us on our toes.
We all are under the protection of energy and all the potential victims of the latent poison of Entropy. The quantity of energy is constant, whereas the quantity of Entropy increases, depreciating energy qualitatively. The sun is shining, but the shadows grow longer. Degradation, equalization, devaluation takes place all around.
The mystery is, at the level of atoms and molecules, each of these processes are reversible. But when we get to bigger collections of atoms, a kind of one-way street emerges —macroscopic irreversibility arises from microscopically reversible parts. Things always happen in the direction of increasing entropy, never the other way around.
Now we know why. There is no microscopic law that tells each particle which way to move. It’s just that there are more methods to disperse energy and less ways to contain energy. Entropy is extremely likely to increase, but it is difficult to decrease. It’s merely random material that obeys the rules of chance.
How will the Universe End – The ‘Big Freeze’
Many theories have been presented such as a Big Rip, or a Big Crunch to predict that how the universe will end. Entropy has a role in it. According to the theory, the universe could end due to a big freeze. Theoretical physicists think that after entropy reaches its maximum, heat in the system will be dispersed equally. This means that there would be no more place for useful energy, or heat, in the Universe, and it would die of ‘heat death.’ Simple said, the mechanical motion within the Universe will cease. Theoretically, during this Big Freeze, the Universe would become so large that gas supplies would be scattered so thin that no new stars could develop. Then, time becomes an infinite hole in which nothing ever happens as there is little to no energy left in the Universe.
Reference
- Entropy, https://www.britannica.com/science/entropy-physics
- Big Freeze, Rip or Crunch: how will the Universe end? https://www.wired.co.uk/article/how-will-universe-end
- Entropy: The Hidden Force That Complicates Life, https://fs.blog/2018/11/entropy/
- Energy conditions and entropy density of the universe, https://doi.org/10.1016/j.rinp.2021.103838
- Why is entropy of the universe increasing? https://socratic.org/questions/why-is-entropy-of-universe-increasing
- Entropy, https://energyeducation.ca/encyclopedia/Entropy
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