Thermodynamics Essay Research Paper ThermodynamicsYou arrive at — страница 2

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temperatures. So why do hot cups cool off? The answer lies in the fact that the universe itself is expanding. Say the universe started off infinitely small and infinitely dense, then expanded at an exponential rate as fluctuations in density increased, eventually forming galaxies. This explanation of the universe would explain the existence of the thermodynamic arrow of time. Because the universe is expanding, disorder is increasing. It can t be stopped. No one and nothing is powerful enough to break the laws of thermodynamics, no one that is, besides Maxwell s Demon. Albert Einstein once said, thermodynamics is the only physical theory of general nature of which I am convinced that it will never be overthrown. If you want to know what s going on in the physical world, you simply

have to follow the heat. In Maxwell s Demon: Why Warmth Disperses and Time Passes, physics professor Hans Christian Von Baeyer tells the story of heat through the lives of the scientists who discovered it, most notably James Clerk Maxwell. He took his inquiries to the atomic scale and used his demon to explain the concepts of energy conservation and heat flow as we observe them. An intelligent, microscopic gremlin that could sort atoms as they flew by, the demon could, in theory, reverse heat flow. Because this great feat of the demon broke the laws of thermodynamics, the question of why these phenomenom weren t observed in nature could only be answered by the fact that the direction in which time was progressing wouldn t allow them to be. To understand the forward flow of time,

Hawking asks us to suppose that God decided that the universe should finish up in a state of high order but that it didn t matter what state it started in (Hawking 187). This would mean that disorder would increase with time. One could observe a broken bottle gathering itself together on the floor and jumping back up onto the table. Such beings would have a psychological arrow of time that is backward. This means that I could take a warm beer, set it on the counter, and in some mysterious way, the colder particles in the room would become ordered, or congregate around the bottle, making the beer cold! This makes the second law of thermodynamics almost trivial. Disorder increases with time because we measure time in the direction in which disorder increases. You can t have a safer

bet than that. Why don t we see broken things gathering themselves together, or slices of pizza jumping out of our stomachs and into our hands? Taking into consideration the two universal metaphysical beliefs concerning irreversibility and time, it is assumed that there must exist at least one physical process that is truly irreversible. [and] Once such a process has been identified it will either itself be found responsible for the one-wayness of our experience of time or it will lead us to the physical process which really is (Fraser 109). What is a necessary condition to define irreversible, is that nature has to have such a preference for a final state that the reverse process becomes meaningless. After all, although a process may not normally run backward, the initial

conditions could somehow be stored. Time moves forward and heat dissipates in our universe because a time- reverse process of life is meaningless (Fraser 111). The laws of science do not distinguish between the forward and backward directions of time, it is the arrows of time that distinguish the past from the future. The big bang theory of the universe says that the universe started off in a smooth and ordered state which began to expand or become disordered. The strong thermodynamic arrow of the expanding universe is necessary for the existence of intelligent beings. For example, in order to live, people have to eat food, which is an ordered form of energy, and convert it into heat, which is a disordered form of energy. So, is time infinite? The answer to this question is not

clear. It all depends on the future of the universe. As long as the universe continues to expand, we will witness the forward progression of time. If, however, the universe were to contract in the future time would run in reverse, slowly at first, then with increasing speed. As explained before, because the time reverse process isn t suitable for the development of life, we wouldn t be around to witness any of this, however there isn t any evidence against it. Most would probably think it absurd that a cup of tea cooling off determines the flow of time, but water runs and stones roll downhill, and this tends in the long run to flatten out the high spots and fill in the low ones. Heat moves from hotter bodies to cooler ones as time progresses. In infinite other ways, also, nature