Thursday, October 29, 2009

Like a virus building a campfire

So again this is something from my E&M class. My professor is Alexei Efros an elderly Russian man with quite the accent. A number of weeks ago he was talking about fusion to the class. This is a rough paraphrase of what he said, you will have to add the Russian accent yourself.


I have many friends who work on this problem their whole lives. One friend, every time I see him I would say 'how long till we have fusion?' and every time he would tell me 'about 5 years' he would say. My friend he is dead now but the last time I see him I ask him 'how long till we have fusion?' and he respond me 'about 5 years' Now it seems that the consensus in the field is that we are making great progress and it really seems we will have fusion in about 5 years. But I would say to my friends I would say 'why we need it?' Perhaps we could use fusion to boil ocean water and irrigate the Sahara, or some project like this, some great project Like making enough water for the Sahara. It turns out we could not do this since this would heat the atmosphere of the earth. But this I tell them I say 'why we need it?' Every reaction has a size. Take campfire, if you build campfire the size of candle it will blow out. The surface area of the flame is too large and it cools rapidly a puff of wind will blow it out. But if you build campfire big enough, build campfire campfire size then it keeps itself warm and the reaction can be sustained. So every reaction has a characteristic size and the size of fusion reaction is size of sun and we want to make it on scale of campfire. This is like if a virus were to try and build campfire, and the relative ratio is about right. We are to viruses like sun is to us. So we try to make fusion on our scale it is like virus or single cell organism trying to build campfire it is ridiculous and we absolutely don't need it just like the virus does not need it, we absolutely do not need it.



The sentiment at the heart of this is being that we do not need fusion I have sympathy for the perspective for but do not agree with it. Eventually we will need fusion power though for now and for the next few decades at least I think we should instead try to use fission power. But I thought the entire episode was very interesting partly because of the perspective from which it is given. Also I think the picture evoked by the analogy of a virus trying to build a campfire is really impressive and striking. Where Efros wanted to use it to show that we do not need fusion I think it is just as effective a way of demonstrating the reason that it is so very hard to make fusion work on our scale.

Wednesday, October 28, 2009

The Law of Grading

Some while back I was sitting in E&M class and we were reviewing relativity. It was all stuff I had seen many many many times and so I was letting my mind wander. I started thinking about the tests that I had recently graded and thanks to the relativity background I came up with the following theorem.

The Law of Grading Efficiency:

Every impartial observer observes a grader to have a grading efficiency less than or equal to that observed by the grader.

Proof: Consider a grader with a stack of papers of height l0 who grades those papers in an amount of time t0 in the graders reference frame. Due to length contraction effects any observer who moves relative to the grader (for instance a passing professor) will observe the stack to be contracted along their direction of motion observing a length l < l0 and due to time dilation effects they will observe that it takes the grader an amount of time t > t0. So an observer in any frame will observe that the grader has less than or equal to the amount of work the grader thinks they have to do and observes that it takes the grader more than or equal to the amount of time to do the work that the grader thinks it takes. Thus the frame of reference which yields the maximum grading efficiency is the graders own reference frame.

Of course there was nothing in the analysis specific to the grading of papers so we obtain an immediate generalization.

The General Work Law:

The person doing the work always perceives the quantity of work they have to do to be greater than any other observer measures it to be and observes the time they have to do it in to be less than any other observer measures it to be.

Tuesday, October 27, 2009

Not Quite Hamlet

So Geocities is finally shutting down. I once had a geocities site and its closure made me go collect all the stuff I had written on it. As it happens what I was thinking of as my geocities site was really an angelfire site and angelfire is considerably better than geocities and is not shutting down or at least not to my knowledge. Even so I will be posting some material from my old geocities site and also material from my angelfire site here. I find the material extremely entertaining mostly because it opens a rather interesting window onto my past of 8+ years ago. This is a joke off of my angelfire site which I thought I would reproduce here.

Hamlet's famous speech

to be or not to be that is the question whether tis nobler in the mind to suffer the slings and arrows of outrageous fortune or to take arms against a sea of troubles and by opposing end them. to die to sleep no more and by a sleep to say we end the heartaches and the thousand natural shocks that flesh is heir to tis a consumation devoutly to be wished to die to sleep to sleep perchance to dream ay theres the rub for in that sleep of death what dreams may come when we have shuffled off this mortal coil must give us pause. theres the respect that makes calamity of so long life for who would bear the whips and scorns of time the oppressors wrong the proud mans contumely the pangs of despised love the laws delay the insolence of office and the spurns that patient merit of the unworthy takes. when he himself might his quietus make with a bare bodkin? who would fardels bear to grunt and sweat under a weary life but that the dread of something after death the undiscovered country from whose bourne no traveler returns puzzles the will and makes us rather to bear those ills we have than fly to those we know not of. thus concience doth make cowards of us all and enterprises of great pitch and moment are with this regard their currents turned awry and lose the name of action. soft you now the fair ophelia nymph in thy orisons be all my sins remembered.

not quite hamlet

To be or not to be those are the null and alternative hypotheses. whether tis nobler in the mind to suffer the slings and arrows of outrageous instructors, or to take up calculators against a sea of math teachers and by playing games ignore them. To try to sleep no more and by a sleep to say we end the brainaches and the thousand broken pencils that students are heir to tis a consumation devoutly to be wished. to try to sleep to sleep perchance to dream. ay theres the rub for in that sleep of math what grades may come when we have shuffled out this testing center, must give us pause. Theres the respect that makes calamity of so long study. for who would bear the whips and scorns of class clowns. The oppressors wrong, the proud nerds contumely, the financial pangs of recieved love, the principles delay, the insolence of hall monitors, and the spurns that patient merit of the unruly takes. when he himself might his quietus make with a bare bodkin? who would fardels bear to grunt and sweat under weary homework but that the dread of something after highschool the undiscovered country, from whose universities no traveler returns puzzles the will and makes us rather to bear those grades we have than fly to jobs we know not of. thus parents doth make cowards of us all, and enterprises of great pitch and moment are with this regard their applicants turned awry and lose the name of dropout.


There are a number of points of this that I am unhappy with and would like to change. Also I think an update for undergraduate/graduate education processes is appropriate and so I will be reposting a new version when I get around to writing it.

Monday, October 26, 2009

Grad School Update

So it has been almost 2 months since I have posted anything. Not surprisingly the sharp decline in my blogging frequency corresponds almost exactly with the time that I began my graduate education in physics. I now have an office in the physics building. Ostensibly I share that office with 3 other people Mark, Rhett, and Tek. Of those three though I have only ever encountered Mark in the office. Even Mark I encounter infrequently so that even though I must share my office it often serves the purpose of an entirely private office. Having started my graduate education it is strongly advised that I attach myself to a research group as quickly as possible. In grad school my classes are going to only begin the story the thing that will primarily characterize my experience in grad school will be my research. So this is a very important decision. While the situation is actually more complicated I will simplify by saying that what I really want to do is particle physics. But there are basically only two professors here which do particle physics DeTarr and Wu. Both are good but both are also towards the end of their careers enough that they may not be taking on anymore students. As is the usual for my way of handling things I have yet to talk to anyone about joining their research group. I keep putting it on my list of things to do but I don't tend to do the things on my list of things to do unless there is a ready punishment for not doing them. Since I could perfectly well allowably not join a research group until sometime during my second year all I am doing by not joining now is costing myself time with the group and time when I could have access to a ready source of support, guidance, and recommendations. That is not to mention access to all sorts of awesome physics goodies like huge telescope arrays and teraquads of data and super computers to crunch it with. There are a couple of professors which are going to be coming to the U in the next year or so and I could become a student of theirs but in the mean time even if I plan on switching professors later on I should attach myself to some research group now.

Other than that graduate school has been rather like my undergraduate education with the one very very important modification that my finances are significantly better. My classes right now are not terribly hard as they are for the most part review and deepening of the more advanced undergraduate courses that I took. Rather ironically I am doing better in the electrodynamics course (a weak point in my undergraduate education) than I am in the math methods class (when you consider that I have an undergraduate degree in math I would say that qualifies it for being a "strong point") I rather hope the lack of high performance in the math methods class is an aberration but time will tell.