Now, what just happened in that process? Well, when you knew that These six particles are gonna diffuse throughout the container. To look more like this, where instance, let's see, Gonna have a situation where the system is going to And then, they're eventually gonna go in this direction. Ones on the left here, they're gonna bounce off this wall. What's going to happen over time? Well, over time, the They're all bouncingĪround in different ways. Have their own individual, their own individual kinetic energy. They have some average temperature, but that means they all each We'll say this is some type of theoretical ideal closed system here. So, I have a container, and I'll make it a, I'm gonna make it a closed container. Why does this make intuitive sets? Well, the best example I can think of is just straight up diffusion. So, let's think a littleīit about this definition. The ultimate closed system, so this is a closed system, is really the universe. But, even those at some levelĪre, they're going to interact with the rest of the universe. Much better approximations of closed systems. And, in research labs, you'll see things that are ![]() And, I can even makeĪ little cover of this to show that we really So, it's not a perfect closed system, but it's a good approximation, because we're at least attempting to isolate it thermodynamically from the rest of the universe. And eventually, that heat will warm up, will be transferred to the ice, and it will warm it up. But, it's not a perfect closed system, because eventually, the heat from the rest of the universe will warm And, we could put, you know, we'd use it to maybe store ice. So, this is, and the way weĭo it is we have some type of an insulating material. We're at least attempting to thermodynamically isolate, isolate the inside of the cooler from the outside, from Probably experienced in the not too distant And, there are, it's very hard to create a true closed There could be interactions from the rest of the universe into the system. Interacting thermodynamically with its surroundings. If I were to just lookĪt the logs and the fire, that's going to be an open system. So, if I had a campfire, so I have some logs and I had my, the flame going right over here. Of open and closed systems, just so we make sure we understand that. Outside of it to interact with thermodynamically. With its surroundings, because the universe is A system that is fully contained, that's not interacting But, we could also say the entropy of a closed system only increases. And, we're really talking about the number of states that a system could take on. You into little bit more of a cosmological scale. And, each of these dots, these are not stars. ![]() The right frame of mind, I have this image hereįrom the Hubble telescope of the night sky. And, I put an exclamation mark here, because it seems like a Other than that it is also questionable whether second law can be applied this way to the whole universe or not.Law of Thermodynamics, one statement of it is that the entropy of the It should be so special that it requires explanation.Ĭritics often point out that prediction and retrodiction is not the same thing forgetting that when one talks about the very "arrow of time" no one can say with justification which is prediction and which is retrodiction. ![]() This reasoning will lead us to conclude that at the moment of big bang the universe was extra ordinarily ordered and most special. But that means even more huge a fluctuation. Either all the parts of the universe we are observing (including our memories of past) has just undergone a HUGE fluctuation right now to give the impression that there was a more ordered past (which is crazy) OR the system was already even more ordered (low entropy) and more special in the past. That's what the mathematics of the laws tells us. Given an an initial condition of a system which is not in the most probable state should go towards more disordered (high entropy) states towards past as well. Since the microscopic laws are time symmetric the same argument can be made towards the past time direction as well. Accordingly its entropy will increase until a maximum value when the system comes to the thermal equilibrium. Since number of disordered states are much higher the system will become more and more disordered with time. Second law follows from the fact that that given an initial condition of a system which is not in the most probable state will tend to go towards the most probable state by the same microscopic laws. They are not biased in any time direction past or future. The basic microscopic laws of physics are perfectly time symmetric. But let me present the reasons, as far as I understood, why people like Sir Penrose thinks so.
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