Does the second law of thermodynamics not apply to the earth since it is an open system?
Question:
My friend converted to atheism. I told him what you said about the second law of thermodynamics, and he said, that only applies to a closed space. He seems to have a comeback for every defense I have. He's always wanting to debate me, prove me wrong, it's like a lion attacking a zebra. I'm pretty defenseless against his arguments, especially since he lives next door to me. His jokes are so rude, “I'm sorry I don't believe in an invisible man in the sky." It's just annoying. I don't know what to tell him. He seems to know every trick in the book. What do I tell him?
Answer:
I had a chemistry teacher in high school tell me the same thing about the second law of thermodynamics. There was just one problem, he was wrong.
"The Second Law of Thermodynamics states that "in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state."" ["Laws of Thermodynamics"].
"The Second Law of Thermodynamics is commonly known as the Law of Increased Entropy. While quantity remains the same (First Law), the quality of matter/energy deteriorates gradually over time. How so? Usable energy is inevitably used for productivity, growth and repair. In the process, usable energy is converted into unusable energy. Thus, usable energy is irretrievably lost in the form of unusable energy." ["Second Law of Thermodynamics," All About Science].
As long as additional usable energy is not being added to a system, then the net energy always decreases. So the question is: is the universe an open or closed system? In other words, is there additional useable energy being added to the universe? The answer is that the universe is a closed system. It has no additional energy being added.
When something is called a "law" in science it means it "generalizes a body of observations. At the time it is made, no exceptions have been found to a law." [Anne Marie Helmenstine, Ph.D., "Scientific Hypothesis, Theory, Law Definitions"].
The claim is that because the earth gets energy from the sun, the earth is an open system. It is a fascinating claim because then how could people have made observations that entropy always increases while remaining on earth? In other words, how could the second law of thermodynamics be discovered and shown never to be violated in a system where it appears to become more orderly because energy is being added to the system?
The second law of thermodynamics states means you can't create a perpetual motion machine because eventually, you'll run out of usable energy. But if the earth is an open system where entropy could increase, then we should have observations of such things, as well as building a perpetual motion machine that would at least keep running until the sun gave out. But there are no observations of this! The second law of thermodynamics has never been observed to be incorrect. Therefore, open or closed, the law remains true.
The reason is simple, as soon as you add an energy source, it becomes a part of the system being observed. The earth is open to energy from the sun, but if you consider the sun and the earth as a system, then you are back to a closed system.
Usually, it is argued that life is able to harness incoming energy and create order. That is true to an extent. The net entropy still increases because eventually, the organism dies. It can organize incoming energy but only to a limited extent. Life can be viewed as a machine designed to temporarily increase order, but in the long run, it still becomes more disordered. See: "Second Law of Thermodynamics - Does this basic law of nature prevent Evolution?"
What is glossed over is that adding energy doesn't increase order. You can't blow up a junkyard (adding energy) and get an airplane as a result. An increase in order means there is guidance and a plan that harnesses the energy. The plan in life is found in the DNA, but even that plan decays over time in the form of mutations. Evolution claims the plan becomes more orderly, but there is no observation of such.
