I’ve heard this so many times that it has become a cliche. I can’t be certain this law exists, but I can certainly confirm that it is true. One of the biggest misconceptions is that kirchhoff’s law is about heating; it is not about cooling. In the case of heat, our bodies are perfectly capable of converting heat into work.
This is a misconception that is so popular because it provides easy answers to other questions that we don’t need to have. This is because, although our bodies can convert heat into work, we arent exactly in the habit of doing so. Think about it. If we were in the habit of using our bodies to convert heat directly into work then we would have to continually use our bodies to cool off in order to do so. But that is not what we do.
We generally use our bodies to cool off by using our bodies like a giant pool pump or like a refrigerator, but why? Well, to cool off, we have to use our bodies in such a way that it is physically possible to cool it off. So we have to take our bodies through a series of physically possible points where it becomes more difficult to cool it off.
In his book The Physics and Philosophy of Heat, physicist Dr. Karl Friedrich Kirchhoff (1821-1896) laid out the three laws of thermodynamics that are the basis of our bodies cooling down. The first law is called the entropy of a thermodynamic system. When it comes to heat it has to do with the amount of energy that can be converted into heat. The second law is called the reversibility of a thermodynamic system.
The third law is called the constancy of entropy. The name comes from the fact that you can always find another point on a thermodynamic system where it will be more difficult to cool off.
The first law states that a thermodynamic system cannot go from a higher state to a lower state without decreasing the entropy of the system. The second law states that you can’t go from a higher state to a lower state without there being a net increase in entropy. The third law states that you can’t go from a lower state to a higher state without there being a net decrease in entropy.
The question is, of course, whether the entire point of thermodynamics is to allow for entropy to decrease, or to allow for entropy to increase. If you can think of a thermodynamic system as a closed loop that has no inlet or outflow, then the entropy of the system should remain constant, and the second law would apply.
In this case, the second law also means that entropy should vanish at the zero point. If the system is unable to work out its entropy then there must be some negative energy available in the system, which is how you can get a negative entropy.
This is exactly why entropy is said to be related to the mystery of the universe. In the quantum world, energy and matter are both waves, but that energy can only convert to other waves. The energy and matter in the universe are both waves, but it’s all waves, not particles. If the universe is composed of waves, and there is a negative entropy, then there must be some matter in the universe that is not waves.
This is exactly what Kirchhoff discovered in the late 1800s, and since then scientists have been trying to figure out just how that negative entropy thing is going to manifest in the real universe. Scientists have tried to predict what will happen to entropy, and have even tried to predict what would happen to reality if you took them too far and altered the laws of physics.