6.14.2007

Worst Death Scene Ever Goes To..... The Universe!!!!

So a general warning, this post is going to have a somewhat nerdy and engineering bent.

Entropy is kind of funny. I have used it alot in my thermodynamics classes. It is one of the state variables that can be used to describe a system and so it combined with the word "Isentropic" is problem solving gold. I first heard about it in chemistry where we learned that the gibbs free energy change is equal to the change in enthalpy minus the change in entropy times temperature. This occured way back in high school and sadly, I think I am only now recovering from it.

What is entropy? I can tell you what it isn't... it isn't a physical thing. You cant touch it, you can't smell it, you cant even measure it but indirectly. In this sense there is no way that entropy can cause anything. Its like saying that the slope of a hill caused the ball to roll down it. Gravity moved the ball, the slope just tells you how fast and how far.

None the less, there is the persistant impression that changes in entropy can cause something to happen and I believe this is a direct result of gibbs equation. And yet, most people ignore the fact that for anything to happen requires energy of some kind. That energy can be in the form of potential energy, kinetic, or whatever. So what then is the entropy term in gibbs energy equation?

Energy! Specifically entropy measures the amount of energy in a system that is unavailiable for work. Sweet. This is a definition we can work with! So in gibbs equation if a change in temperature, or more generally a change of state, frees up some energy to do work. And if there is energy availiable to do work then things can change which is the whole point of gibbs equation.

What are the different ways that we can have energy present but not availiable for work? Well, we know from intro thermodynamics ( and physics I think, but that was probably 8 or 9 years ago at this point so I am not sure if it was in it) that the efficiency of any heat engine has to be lower then that of the Carnot heat engine which relates the max efficiency to the highest and lowest temperatures of the system (kind of). So right there we have the fact that based on temperatures (a state variable) we can vary the amount of usable energy we have. Voila, I give you entropy.

What else? Well, in chemistry we have many different forces and interactions taking place that are irrelevent for power cycles. Namely, inter and intramolecular forces. In both cases we now have a positional potential energy. This energy is kind of like the energy stored in a bunch of magnets that you tacked to a table. Based on the arrangement you can have positive or negative potential energy (to many north poles facing north poles or conversely to many north poles facing south poles). In anycase the arrangement of molecules in a liquid gas or solid can be thought of in much the same way. If there is lots of order in a system then essentually all your north poles are facing other north poles and you can use the fact that the system wants to force itself apart to do work. If, however, there is alot of dissorder then for every north pole facing a north pole there is likely a north pole facing a south pole that cancels it out.

How does this relate to the heat death of the universe? Well there must be a reason that the universe tends to disorder and I like to think that it is the fact that nature abhores an energy gradient. As we have stated, any time we have something that is well ordered it is almost the equivilent of saying that we have energy we can use all nice and localized in one area. So the tendency towards disorder is the tendency to spread out this energy.

But why does energy spread? Why do energy gradients tend towards zero? Thermal fluctuations helped along by a tiny dose of quantum uncertainty mean that any barrior to energy movement is likely to be crossed as time goes to infinity. So any barrier that is put into place to localize energy or equivently to create order is going to be crossed and that energy will spread into the surroundings. Since the probability of that crossing is proportional to the amount of energy present it is more likely for energy to leave then to enter. Maybe only slightly so, but it is inevitably the case.

There are alot of details missing but basically it makes sense to me and I supose that is what counts :-)

6.06.2007

Don't read this.

I don't entirely know why I am writting about this. There is nothing new about what I am experiancing. I suppose it is the oldest and most universal experiance... period. But, I have never experianced it like this.

That, of course, suggests that I have experianced death. My first came when I was pulled out of a line waiting to get on busses for a field trip in eighth grade. It was the end of the year and we were being treated to a day at the local bowling ally / miniture golf / go carts / arcade place. I even remember handing my little zip lock bag of quarters to one of my friends because I knew, in a sense, what the office secretary wanted to see me about. And yet, I didn't. It was still a surprise because I never really saw my great grandfather towards the end. I just knew he was not well and really, death wasn't something that happened to people I knew.

Then there were the car accidents. Each one creeping closer, first someone I barely knew. Then the kid who was cool and bad ass and yet still would talk to me if we had a class together. Adam Rusnak came next. I still remember the shock of losing someone you see everyday. Chemistry class was never the same.

Last was Vasu. I could write for years and still never capture what I felt after he died. So sudden, we were planning on going to India together just two months later. Then walking through a funeral parlor not wanting with every fiber of my body to be seeing and hearing it all.

But Grandpa R... knowing and yet not letting your self know. Little remarks about how its somehow funny that he still thinks that he will be able to drive again (although deep down we think he knows he wont). The daily regimend of pills and inhalers and exersizes and precautions and worries that is wearing down my grandmother. Conversations, if they last longer then 10 minutes, that are about everything and somehow nothing.

I have never felt like this. Death is not supposed to be like this. It is supposed to come up from behind and snatch those things away from you that you care most about. It teaches you to charish life and those around you. It gives meaning and urgancy and beauty to everything.

But how can you find purpose or take meaning from something that hasn't happened yet but already has? You are stuck in a limbo of numbness and purposefull ignorance. Feeling the future fill the present and doing your best to look past it.

And perhaps that is why I am so upset. Death, for me, is not an inevitability but a game a chance. Role two dice and you will be surprised how long you can go before you role snake eyes. You can also be surprised how quickly they can appear. Regardless, there is no explicit end game. You role as long as you can.

That is what is wrong , it just doesn't seem right to role expecting to lose.