On this day in physics: 21 January 1962- Happy Birthday to Dutch Theoretical Physicist Erik Verlinde, who turns 54 today. Erik's specialty is in string theory, and introduced a controversial theory for gravity known as "entropic gravity." This explains gravity not as a fundamental force, but rather as a byproduct of the fact that systems tend to increase in entropy. One draw to this theory is that it correctly predicts the strength of Dark Energy, a previous word of the day![Source.]
Word of the day- Entropy- According to Wikipedia: "In thermodynamics, entropy (usual symbol S) is a measure of the number of specific realizations or microstates that may realize a thermodynamic system in a defined state specified by macroscopic variables. Entropy is commonly understood as a measure of molecular disorder within a macroscopic system." Okay great but what does that mean exactly?? It means that entropy is a concept heavily involved with the thermodynamics of a system. The second law of thermodynamics is as follows: In a reaction, or any sort of interaction between bodies, the entropy always increases. OK, so we know that it's always increasing, but so are a lot of things, it doesn't really explain what entropy is. From hyper physics: "Entropy is a measure of the amount of energy which is unavailable to do work." An lastly, and probably most simply, it is the measure of disorder in a system. So, the the second law of thermodynamics really says that the disorderedness of a system is always increasing. This is probably the easiest way to think about it. Entropy is also known as "time's arrow". Entropy is always increasing, so if you were to see a series of images of a system's evolution, and you know the amount of disorderedness of each image, ordering them from least to greatest would put them in chronological order. Think of it this way. If you were to see a series of pictures of a glass of water falling off of a table and shattering on the floor, it would be possible to place them in chronological order, yes? Why is that? If you were to place a few drops of red dye into a glass of water, and not interact with that system in any way, eventually the dye would evenly disperse through all of the water, making it with the lightest reddish hue possible. This is the most disordered state possible. When a system cannot possibly become any more disordered, it is considered to be in equilibrium.
Killer Resource: Neil DeGrasse Tyson talks about Entropy and how life exists on Star Talk. We are somewhat ordered organisms, and we like to "order" items. How is this possible if entropy is always increasing???
Keywords: Thermodynamics, Entropy, Star Talk, Equilibrium, Disorder, Chaos, Order
