O que faz a água sair da torneira?

Desde que fiz o texto "Sobre Torneiras",várias pessoas já entraram no blog buscando a resposta da pergunta: O que faz a água sair da torneira? Mal sabem as pessoas que fazem essa busca, que este é o blog de um físico, e como bom físico, eu vou tentar explicar da maneira mais complicada possível o porquê da água sair pela torneira!

Isto ocorre devido a um princípio básico da hidrostática, chamado princípio dos vasos comunicantes. Vasos comunicantes é o termo utilizado para designar um sistema de dois ou mais recipientes interligados por dutos fechados, ou seja, todo o sistema de água de uma cidade, é um grande sistema de vasos comunicantes. E segundo a hidrostática, caso o líquido no interior dos tubos seja homogêneo, ele deve atingir a mesma altura em todas os recipientes que se interligam, como ocorre na figura abaixo.


O que faz com que a altura seja sempre a mesma é a pressão. Tanto a pressão atmosférica, quanto a pressão gerada pelo peso do próprio líquido dentro dos recipientes.

Imagine agora, se colocarmos um furo, abaixo do nível do líquido, em cada um dos recipientes. O líquido vai começar a vazar, e se inserirmos um regulador de vazão após o furo, então teremos uma TORNEIRA!!!

Concluindo: Para uma torneira funcionar, temos que ter um sistema de vasos comunicantes, onde a fonte de água, deve estar sempre a uma altura mais elevada que todas as torneira, ou chuveiros, ou qualquer outro aparato que verta água. Caso contrário, não sairá água das torneiras. Por esse motivo, é que todas as caixas d'água existentes, sempre ficam no topo dos edifícios, ou então, são as estruturas mais elevadas em cada região!

É tão simples, que eu nem consegui complicar, e colocar integrais no meio! Bah! :P

Random Thoughts

Sometimes The Dreaming is much more cruel than the real life...

I have a feeling that a war is about to start... But that was just a mad dream... and cruel, not because of the war...

I think COPOM sucks! And they really do not understand nothing about economy, or they do not really care for the real economic growth of Brasil.

The second season of my game started yesterday... Time to put fear again in the heart of my players!

Eu sou a favor da regulamentacão (o cedilha não está funcionando no meu teclado) da profissão de Físico.

P.S.: The last thought was written in portuguese mainly because I don't know how to say "regulamentacão" in english. It is also just a matter of internal politics, that I don't think concern anyone but the Brazilian physicist population.

Dia de Falar como Físico

Próximo dia 14 de Março será instituida uma nova data comemorativa. O Dia Internacional de Falar Como um Físico.

Não existe data melhor do que esta, afinal dia 14 de Março é data do nascimento do mais famoso físico de todos os tempos, Albert Einstein, e se você escrever a data do modo inglês, com o mês vindo antes do dia, teremos o dia "Pi" (3.14).

Está data é para todas aquelas "infelizes" pessoas que decidiram que física era coisa de pessoas com distúrbios psicológicos irreversíveis, e decidiram seguir qualquer outra profissão, libertarem o seu lado físico e abusar daquela linguagem hermética que só os físicos parecem ser capazes de compreender. Assuste as pessoas nos ônibus, nas ruas, seu vizinho, estudantes de ciências humanas, ciências biológicas, e artes falando sobre distorções espaço-temporais, singularidades, instabilidades magneto-hidrodinâmicas, cromodinâmica quântica, termodinâmica de não-equilíbrio, etc, etc... Use todas aquelas palavras estranhas que você por ventura tenha lido em algum título de tese, dissertação ou artigo sobre física, e crie as mais variadas frases misturando aquelas palavras bizarras. Seja criativo!


P.S.: Divulgando novas datas comemorativas, saibam que dia 8 de dezembro é o Dia Internacional de Fingir Ser um Viajante do Tempo. (Fonte: Efeito Ázaron). Valeu Quase-Físico, por compartilhar o conhecimento de data importantíssima com todos nós!

Tesla Anti-Theft Device

Have you ever wondered about what kind of anti-theft device would be able to make even the most professional of thieves scared of stealing your car!? Or even to scared away those pesky people trying to sell thing or begging while you are standing still in the red traffic lights!? Here is the answer for all your problems!!!

BEHOLD!!! THE TESLA ANTI-THEFT DEVICE!

Now I have a good reason to buy a car!! Just to install a Tesla Anti-Theft Device and start to vaporize car thieves everywhere!! Tesla coils are sooooo damn cool!!!

Your health and the Earth destruction.

Today, wandering through the cyberspace, two things caught my attention. Two very interesting top 10's. The first one is "The Top 10 Bad Things That Are Good For You". I am not going to spoil that here, but it worth to see it. I, particularly, loved the number 7. (I guess I will turn myself in an alcoholic just to have a "good" reason to use that... Hehehehehe).

At the same place, looking at the other Top 10's, I found this other one: "Top 10 Ways to Destroy Earth". The fun in that one is a little more restricted to physics, but if you are nerd enough, I am sure you will understand and laugh at least a little bit with that.

My source was a very interesting blog (in portuguese), that it is very worth to take a look if you can understand it: Favoritos.

Entropy and Global Warming

Saturday night, I am alone at home, after being part of a very funny "mock" Thanksgiving with the Astronomy Grad Students here in Ann Arbor. The party was really awesome, with great people and great food, but this time I decided to stay clean.

So here I am, sitting with my computer in my lap, hearing some music, in full control of my consciousness, and then inspiration came. Actually I was thinking about writing about this thing for a while now. The post today will be about Global Warming. Yeah... This will be fun. An excellent way to spend time in a Saturday night.

As a Doomguard, and a physicist I have to think in Global Warming in terms of Entropy. Global Warming is caused just by the increase of Entropy of our small planet. The increase of Entropy is always a natural process, the real point here is that due to humanity extremely high needs of energy, the natural process is being accelerated to uncontrolled levels. Of course, to produce energy, you have to produce heat, and heat in a manner of speaking is Entropy. There is no way to produce energy without increasing the Entropy of your surroundings.

As I share the Sinker point of view regarding Entropy, I guess in this case I have to help the Regulators, to reduce a little bit the Entropy increasing rate of the planet. Global Warming in my point of view, is not directly related to the Greenhouse Effect. The amount of carbon dioxide in the atmosphere is just proportional to the energetic necessities of the world, due to the fact that most of the energy produced in the world came from thermal power plants, and the burning of oil or coal, and the efficiency in these processes are at most around 50%. More efficient ways to produce energy will decrease the rate of Entropy gain of the planet, but Entropy will still increase, and then there will be different sources, alike Greenhouse Effect today, to blame for Global Warming. Another way to help decrease the Entropy gain of the planet is to decrease the energy needs of humanity, but that is probably out of question. The energy needs of this civilization just tends to increase, uncontrollably, and this will also lead to an uncontrollable increase of heat produced, and then no way to escape from the fearsome Global Warming.

Energy consumption will not decrease, so humanity needs to find a way to control its needs for energy, so Global Warming can be controlled. And humanity also needs to find more efficient ways to generate energy. These two things would help a lot towards controlling this problem, but anyway, the increase of heat will continue. As I believe in the laws of thermodynamics, and I don't believe in a perpetual energy source 100% efficient, the only way to solve this problem would be to produce energy using sources outside the Earth. The most straightforward answer for this conundrum is Solar Energy. That is the only actual way of reducing Global Warming on Earth currently known. The Sun is like a battery, there is no known way of pulling more energy than it generates, but it produces energy enough to sustain life on Earth for billions of years yet. Using the Sun energy we can lower the Entropy of the Earth, and in this way end once and for all the warming problem of the planet. Eventually the Sun's Entropy will reach values so high that it will become a red giant, almost enveloping the Earth orbit, and destroying this beautiful planet, and all traces of civilization here.

We can surely create a lot of power plants in Mars soil, this way we can generate enough heat to warm the martian surface, making the planet more susceptible to accept earthlike life-forms. Then using some interplanetary energy tranfer methods, yet unknown, to bring this energy to Earth. Maybe the microwave radiation background generated by the Big Bang could also be used as a clean energy source. There are many possibilities, but currently the only feasible one , to really reduce Global Warming, is the use of solar radiation as a source of energy. Nothing else is really a solution. While most of the energy generated in Earth come from earthly sources, there will still be heat being generated and the Entropy will still increase.

This is Entropy berk! It can be delayed but never defeated. So, lets embrace Global Warming, because we cannot run away from it, yet. Solar power is somewhat a reality, but only an ephemeral part of humanity energy is generated that way. There is a long and winding road ahead of us before humanity can use the Sun as its most important source of energy again. Decay, Death and Destruction will be always in our doorsteps, one way or another, so be used to it...

Ultimate Musical Geekyness

People know I am a true believer in Rock'n'Roll, but unfortunately I don't know how to play any kind of instrument. The only musical experience I had was playing Guitar Hero. But I really want to learn how to truly play an electric guitar someday.Well... At least, that was what I thought until I have seen the most amazing musical instrument ever built by man... The "Geekiest" Musical Instrument Ever Built...



Two Tesla Coils playing the "Super Mario Bros." theme. It is geeky, and it's pure Heavy Metal.

The 2007 Ig Nobel Prize Winners

Each year the Institue of Improbable Research honors achievements "that first make people LAUGH, and then THINK" with the Ig Nobel Prize. The winners of the 17th First Anual Ig Nobel Prize are:

MEDICINE: Brian Witcombe of Gloucester, UK, and Dan Meyer of Antioch, Tennessee, USA, for their penetrating medical report "Sword Swallowing and Its Side Effects."
REFERENCE: "Sword Swallowing and Its Side Effects," Brian Witcombe and Dan Meyer, British Medical Journal, December 23, 2006, vol. 333, pp. 1285-7.

PHYSICS: L. Mahadevan of Harvard University, USA, and Enrique Cerda Villablanca of Universidad de Santiago de Chile, for studying how sheets become wrinkled.
REFERENCES:
"Wrinkling of an Elastic Sheet Under Tension," E. Cerda, K. Ravi-Chandar, L. Mahadevan, Nature, vol. 419, October 10, 2002, pp. 579-80.
"Geometry and Physics of Wrinkling," E. Cerda and L. Mahadevan, Physical Review Letters, fol. 90, no. 7, February 21, 2003, pp. 074302/1-4.
"Elements of Draping," E. Cerda, L. Mahadevan and J. Passini, Proceedings of the National Academy of Sciences, vol. 101, no. 7, 2004, pp. 1806-10.

GHofXaos's Note: In some more years, a fully-functional anti-wrinkling bed sheet will be available at the market, and then every kind of anti-wrinkling stuff. The iron will be a thing from the past. Even some kinds of plastic surgery will be a thing from the forgotten past.

BIOLOGY: Prof. Dr. Johanna E.M.H. van Bronswijk of Eindhoven University of Technology, The Netherlands, for doing a census of all the mites, insects, spiders, pseudoscorpions, crustaceans, bacteria, algae, ferns and fungi with whom we share our beds each night.
REFERENCES:
"Huis, Bed en Beestjes" [House, Bed and Bugs], J.E.M.H. van Bronswijk, Nederlands Tijdschrift voor Geneeskunde, vol. 116, no. 20, May 13, 1972, pp. 825-31.
"Het Stof, de Mijten en het Bed" [Dust, Mites and Bedding]. J.E.M.H. van Bronswijk Vakblad voor Biologen, vol. 53, no. 2, 1973, pp. 22-5.
"Autotrophic Organisms in Mattress Dust in the Netherlands," B. van de Lustgraaf, J.H.H.M. Klerkx, J.E.M.H. van Bronswijk, Acta Botanica Neerlandica, vol. 27, no. 2, 1978, pp 125-8.
"A Bed Ecosystem," J.E.M.H. van Bronswijk, Lecture Abstracts -- 1st Benelux Congress of Zoology, Leuven, November 4-5, 1994, p. 36.

GHofXaos's Note: I guess a lot of people will not be able to sleep at night for quite some time. Some people might turn themselves into psycho-cleaners, and then evolve into psychopaths...

CHEMISTRY: Mayu Yamamoto of the International Medical Center of Japan, for developing a way to extract vanillin -- vanilla fragrance and flavoring -- from cow dung.
REFERENCE: "Novel Production Method for Plant Polyphenol from Livestock Excrement Using Subcritical Water Reaction," Mayu Yamamoto, International Medical Center of Japan.

PRESS NOTE: Toscanini's Ice Cream, the finest ice cream shop in Cambridge, Massachusetts, created a new ice cream flavor in honor of Mayu Yamamoto, and introduced it at the Ig Nobel ceremony. The flavor is called "Yum-a-Moto Vanilla Twist."

GHofXaos's Note: You can't trust nothing vanilla- anymore.

LINGUISTICS: Juan Manuel Toro, Josep B. Trobalon and Núria Sebastián-Gallés, of Universitat de Barcelona, for showing that rats sometimes cannot tell the difference between a person speaking Japanese backwards and a person speaking Dutch backwards.
REFERENCE: "Effects of Backward Speech and Speaker Variability in Language Discrimination by Rats," Juan M. Toro, Josep B. Trobalon and Núria Sebastián-Gallés, Journal of Experimental Psychology: Animal Behavior Processes, vol. 31, no. 1, January 2005, pp 95-100.

GHofXaos's Notes: I ever thought that rats were one of the most intelligent creatures in planet Earth, superseding by far the human primitive intellect. This just confirms my thoughts. Only sometimes they cannot tell the difference... Amazing!

LITERATURE: Glenda Browne of Blaxland, Blue Mountains, Australia, for her study of the word "the" -- and of the many ways it causes problems for anyone who tries to put things into alphabetical order.
REFERENCE: "The Definite Article: Acknowledging 'The' in Index Entries," Glenda Browne, The Indexer, vol. 22, no. 3 April 2001, pp. 119-22.

GHofXaos's Note: I always had problems with "The" while indexing my songs!! A real must this article. I'm sure it will help me solve a lot of problems with indexing.

PEACE: The Air Force Wright Laboratory, Dayton, Ohio, USA, for instigating research & development on a chemical weapon -- the so-called "gay bomb" -- that will make enemy soldiers become sexually irresistible to each other.
REFERENCE: "Harassing, Annoying, and 'Bad Guy' Identifying Chemicals," Wright Laboratory, WL/FIVR, Wright Patterson Air Force Base, Ohio, June 1, 1994.

GHofXaos's Note: Make love, not war!! I hope this hideous device does not befall in the wrong hands. Imagine some gay mob throwing that in the middle of a Hell's Angels meeting, or in the middle of a 90%-male-students class. The consequences could be disastrous to say the least!! (FEAR)

NUTRITION: Brian Wansink of Cornell University, for exploring the seemingly boundless appetites of human beings, by feeding them with a self-refilling, bottomless bowl of soup.
REFERENCE: "Bottomless Bowls: Why Visual Cues of Portion Size May Influence Intake," Brian Wansink, James E. Painter and Jill North, Obesity Research, vol. 13, no. 1, January 2005, pp. 93-100.
REFERENCE: Mindless Eating: Why We Eat More Than We Think, Brian Wansink, Bantom Books, 2006, ISBN 0553804340.

GHofXaos's Note: This device could solve the famine problem in the world!! A self-refilling, bottomless bowl of soup!!

ECONOMICS: Kuo Cheng Hsieh, of Taichung, Taiwan, for patenting a device, in the year 2001, that catches bank robbers by dropping a net over them.
REFERENCE: U.S. patent #6,219,959, granted on April 24, 2001, for a "net trapping system for capturing a robber immediately."

GHofXaos's Note: They will not be expecting that. Unless they read the Annals of Improbable Research (a must reading even for bank-robbers).

AVIATION: Patricia V. Agostino, Santiago A. Plano and Diego A. Golombek of Universidad Nacional de Quilmes, Argentina, for their discovery that Viagra aids jetlag recovery in hamsters.
REFERENCE: "Sildenafil Accelerates Reentrainment of Circadian Rhythms After Advancing Light Schedules," Patricia V. Agostino, Santiago A. Plano and Diego A. Golombek, Proceedings of the National Academy of Sciences, vol. 104, no. 23, June 5 2007, pp. 9834-9.

GHofXaos's Note: A very relevant study about such an extremely intelligent creature that can differentiate between backwards-Japanese and backwards-Dutch, and whatever other misterious backward-language we do not even imagine yet. I am sure they can speak scramblespeak too, and backward-scramblespeak!!

Source: Improbable Research

Quark Sexy!

Como é sabido, pelo atual modelo padrão, os quarks junto aos léptons são os constituintes básicos da matéria. Para se distinguir os vários tipos de quarks e léptons, deu-se a cada um deles o que a física de partículas chama de sabores. Os sabores dados aos léptons são três: Elétron, Mu (da letra grega, mi) e Tau. Já para os quarks os pesquisadores da época resolveram ser mais engraçadinhos, e deram os seguintes sabores: Up, Down, Top, Bottom, Strange e Charm.

Após uma pequena discussão, numa comunidade da qual eu faço parte no Orkut, chegou-se a conclusão que o melhor sabor oposto para o Quark Strange, não seria o Quark Charm, mas sim o Quark Sexy. A partir dessa discussão, então, foi criada uma petição na Internet, para que o nosso amigo Quark Charm seja renomeado Quark Sexy! Que convenhamos, combina muito melhor com o Quark Strange que o Quark Charm. A petição para mudança de nomes está em:

http://www.petitiononline.com/chtosexy/petition.html

Ajude a fazer a história da Física, ajudando a escolher um nome mais apropriado para um dos constituintes básicos da matéria. E tenho dito!

P.S.: Valeu por ter criado a petição Quase-Físico!

Code almost ready, and running...

...and so, at long last, I have solved the problem that was haunting me during this past month. My code is almost ready, and as far as I know, it is working properly. The main coding is ready, and with some other small changes in the last routine, everything will be working soon... I expect to have it ready by the end of this week.

During this past month I have barely touched the code. My adviser decided to give me some other task, and I was working with that for the past few weeks. Last week I have finished the task, and I have showed her my first results yesterday. She was quite excited about them, but they are only preliminary results. I still have to refine them. The task was to use the original program I am working with (prior to applying the changes I have done) to calculate the Lyman alpha line profile for TW Hya, a well known T Tauri star. The Lyman alpha line transition is a transition from the first energetic level to the second energetic level of the hydrogen atom. The photon generated in such a transition is in the ultraviolet part of the spectrum, and most of the contribution to the formation of this line comes from the magneto-accretion funnel, and the accretion shock region in the stellar photosphere. Enough to talk about that... I don't think anyone but me (and the people who work with me) is really interested in knowing more about that anyway... (But if anybody has any question about it, I can try to answer... :P)

So, Monday I gathered all my courage and started to figure out the problem in the code again. My mind was much more calm than when I last tried to work with that, some weeks ago. I decided in my mind that my deadline to finish this was this week, and so I opened the code, took a deep breath, and started to debug it, again... Running the program many times, looking the output files, searching and seeking the errors from one point to the other point of the code, until finding the very routine that was the source of the error or errors as I came to discover moments later.

Looking in a more detailed way at the output files, I have found something that I was not expecting. An error in the density values that I have not seen before. The code was having problems in "remembering" where some points really were. If the point is in the magneto-accretion funnel region, the density is calculated using one law, but if it is in the diskwind region, the density was calculated using another law. The problem was that the ONE code line, that was "remembering" the code where each of the points were, was misplaced and then the code was a little confused about the whereabouts of each point, and as such the densities were not correct everywhere. The error was corrected, the program ran, the densities were all corrected this time, BUT the end results were still wrong...

More work... more debugging... insanity taking over my mind again... The Cube... insomnia...

Then today, after a good night of sleep, and after arriving very late at my office, I started the work again. Seeking the errors through the code, from one variable to the previous erroneous one. After tracing back the error through a lot of variables, I have finally discovered that the source of my nightmares was in an interpolation routine. I have changed that routine a couple of months ago, but I have failed to notice a missing point there, and the thing that I have forgotten to change was the source of all my problems. With the previous line of code the program was looking for something like the "j+1" component of a vector-variable that had only a "j" number of components. And so the "j+1" component that was being read somewhere by the program was a random value coming from some unknown and sinister part of the memory (it is usually the next value in the memory block after where the vector-variable was stored). And that random value was affecting all my calculations, spreading the error throughout the other values like an infectious disease. Something that should be positive, had random negative values. Values that should be as low as zero, were acquiring values than a googol (not kidding here, some values were around the order of 1.e+290). And some other strange behavorial problems...

I changed that line and now everything is working properly. The output values for the source function and the average line intensities at each point in the system are being calculated correctly. Next step is to change the program that calculates the line profiles. No more hautings...

At least some good news concerning my work...

Life

I am an astrophysicist student, but that is not what I am! What defines me? My work helps to define me, but I am not defined by my work! Part of what I am I have already discovered, and it is what I have lived and already learned, and part of it is what I am living and learning right now. But there is a part that I have yet to discover, and that is what keeps me going further and further...

Life is something so limited. People need to follow so many rules in life. People need to breath. People need to eat. People are bound to the Laws of Physics, and other undisclosed laws that seems to be beyond physics at all. People even have to follow rules defined by other people, and these other people not always want the best for whom they are making the rules for... But they have to live within these limits during many decades. And these rules are what life is for a great majority of people around the world. And for great majority of people, the only thing that differentiates one person from another are their work, their family and their friends. They don't even realize that they are trapped inside this Tome of Laws, and that their life is simply following these laws.

A long time ago I realized that I did not want to follow these rules anymore. I don't want to have a "normal" life. I don't want to live a job to earn money, then spend the same money, repeating the cycle until the end of my days, with some small variations in what I am spending the money with: myself, family, friends (these thing not even vary that much, do they?). I don't want to follow any religion, because I don't trust the people who made of religion their particular business, and I really don't want to follow a path that was defined by others who think they know the path to find the ultimate salvation and redemption. What is redemption and what is salvation after all?

I want to have a work, because I learn things while I am at work, things that are not always that useful for the society, but I don't care about what they think is useful or not, I just want to learn. Money is just one of those society-imposed laws, so for now I still have to earn some if I want to live, since nowadays there are some critical biological laws that requires the use of some amount of money to be followed (food, health care, water...). But for me life goes far beyond work, money, and the predefined religions. I want to learn things that are beyond the scope of my work, I want to learn how to see the hidden pattern and the hidden chaos that is beyond the veils of Reality. My Religion is my Unpredictable Life, and for me is the wisest path to follow. Will it leads me to my redemption and salvation? It will surely take me where I want to go, even that I do not know yet where is this place.

The most beautiful thing about one's life is that is not simply defined by oneself. The life of everyone is a great entangled web. Every person in the world is connected to this great web, and every person helps define the life of everyone else. This is the great source of chaos and unpredictability that rules everyone's life. And there is much more to this Web than only people, there are many other things keeping life churning and moving in a ever-changing way. But even this endless source of chaos is not able to make most of the people realize how great is life, and how all those "chains" are limiting their true life's potential.

I am a still caged apprentice of life. My mind insanely seeks things that are still beyond my reach, but things that I know are "true". I am not The Perfect Model Worker, nor do I want to be one during my entire life. The riches I seek are far beyond anything money can buy me. The path I have chosen to follow does not lead me to Redemption nor even to Salvation as envisioned by the predefined "great" religions, instead it leads me to the Frightening and Obliterating Unknown. And I am not afraid.

I am a Madman. Perhaps a "Dreamer". I have seen small glimpses of the "True" for the most ephemeral of moments, and that was the source of my insanity and what drives me to my Quest. I remain locked in an Asylum, that is not just "another one" but "THE". I have already one Key in my hand, but there are yet many others to obtain. I will find them all, and I will not be afraid of use them...

That is my True Vision about Life, but still that is not what I am...

Vida inorgânica e MHD

Acabei de ler uma notícia deveras interessante. Parece que descobriram alguns indícios de que é possível haver vida inorgânica. Muito bizarro, mas quem disse que a vida tem que ser orgânica, ou seja, tem que ser baseada em átomos de carbono!? Quero só ver onde isso vai levar, afinal foi só uma simulação por computador, onde normalmente são utilizadas vários tipos de aproximações, mas apesar disto, os resultados obtidos por elas costumam refletir bem a realidade. Senão, elas não serviriam para nada, e eu eu não estaria aqui tentando fazer meu modelo funcionar! :P

Vale a pena dar uma olhada. A vida, afinal, é puramente MHD (Magneto-hidrodinâmica). :P

One less problem to solve...

Take heed and bear witness to the truths that lie herein, for they are part of my legacy to the world (Not even a little bit pretentious, huh? It was just a small reference from some PC Game of 11 years ago, that I am sure made a lot of people addicted to it, and I even have written something about it a time ago, using the same sentence). And so it came to pass that the problem that was haunting my dreams during these last days was at last solved. The optical depths is, again, at acceptable levels as also is the density of the excited state that was the cause of the problem. The error was not in the code after all, it was in the input file that was read by the code before, and that was used as a configuration file. The gas temperature in this file was a little too high, and it was the cause to the great value for the density of the second excited state in the hydrogen atom, and the causing the great optical depth for the transition from the 2 excited state to the first excited state!

Time to go on, and now patch some other errors... One less..

Optical depths and the atomic excitation levels densities...

After a while I have discovered what was causing that cyclopean optical depth values in my calculations. The problem was the density of the excited atomic state, it was far higher than it should be, and it is still that high. After discovering the source of the problem I have formulated various possibilities for what was the cause of this erroneous value. The possibilities were: an integration error during the calculations of the solid angle covering the star, or the accretion disk or the disk of my system, but after taking a look at these values, I have concluded that those values were fairly good; another possibility were something wrong during the velocity gradient calculations, but again these values had the correct order of magnitude that I should expect. I have not changed anything in the routine used to calculate the densities of each of the atomic excitation levels needed, so it should be correct, after all the program still works as it should work for what was his prior objectives.

After finishing checking those possibilities, I began to wonder where was this error. All the input the input values are what they should be, but the output value is nowhere near what is acceptable. Then I thought about the many iterations needed for this calculation, and I remember that all these values, for every iteration are saved in a general output data, not only the last iteration values. After that I decided to take a look about how these values evolve through each iteration, and I saw it... The problem is in the first value for density that was calculated, even before any kind of solid angle integration or even after using the routine that calculates the excitation equilibrium states for the system. I was looking for the problem in the wrong place, now I have to start looking in the right place.

And so, here I go again... I expect that this time I can find the problem.

Calculated optical depth...

And so after solving a lot of problems in my program code, I was already happy because it is almost working properly. I just have found out that it was calculating, I think, correctly the source function of each point, it was just having a small output problem (a problem with the correct value not being saved in the output file). And then, I spotted it... An impossible value... Something that made me laugh, almost insanely, due to absurdity of what I was seeing on the screen... The calculated optical depth, something that should have the value of the order of a unit, was with values of an order of magnitude of 10^5 and reaching even 10^9. I don't think any photon could cross that region not even in a googol years... :P (I am just exagerating about the googol, of course. And for people who does not know what in the Nine Hells, also called Baator, is a googol, it is 10^100, or 1 followed by onde hundred zeros)

The only thing I can do for the time being is to laugh... Then I will try to find out where in the program lies this problem!

For people who does not know what does optical depth means, it is related to the escape probability of photon to leave some region of space. The higher the value, the smaller is the chance of it to escape before being scattered or absorved by the medium, meaning that more opaque is the medium. That is the kind of thing that an astrophysicist tries to calculate, and/or uses in their job. Total madness if you want to know my opinion about that, but it is also pure beauty! =D

Another problem, but the good thing is that I could saw it before going further. Now I have to spend some time on it, and I guess it will be quite an amount of some time... Bah! And I am still laughing... HAUhAUhUAHauhuHAuHAUhUAHuHAuhaa....

Novas 7 Maravilhas do Mundo & Gordon Conference

Eis então que o Cristo Redentor foi eleito uma das novas 7 Maravilhas do Mundo. Definitivamente não concordo! Pode até ser o símbolo do Brasil, e como Brasileiro eu deveria estar achando ótimo, mas acho que entre os monumentos votáveis, o Cristo Redentor seria das minhas últimas opções. Talvez eu votasse no Cristo Redentor, caso esta escolha fosse feita daqui há alguns séculos, 500 ou 600 anos pelo menos, e este ainda estivesse de pé. Existem outros monumentos que representam realizações muito mais notáveis que o Cristo Redentor, e que depois de mais de mil anos ainda estão de pé. E historicamente, ou culturalmente falando, a maioria deles são mais importantes que o Cristo Redentor. Talvez se estivessem limitado a época da construção nos últimos 100 ou 200 anos, eu votaria nele com quase certeza, mas não dá pra comparar o Cristo Redentor, com as Pirâmides do Egito, a única das maravilhas do mundo ainda de pé, Angkor-Wat, Stonehenge, Acropolis, e nem mesmo com nenhuma das maravilhas eleitas.

Pra quem não sabe, as novas maravilhas do mundo são: A Grande Muralha da China, Petra (Jordânia), Machu Picchu (Peru), Chichén Itzá (México), O Coliseu (Itália), Taj Mahal (Índia) e o Cristo Redentor.

Voltei de uma conferência em South Hadley, MA, ontem. 12 horas de viagem na ida e na volta. A conferência (Gordon Research Conference: Origins of the Solar System) foi ótima. Encontrei algumas pessoas de outros países, mas a maioria absoluta eram americanos, como o esperado. Foi um encontro de astrofísicos, planetologistas, geólogos e geofísicos. Um grupo bem amplo de cientistas, mas mesmo assim não estava lotada, talvez umas 140 pessoas no total. Com tanta coisa diferente, não dá pra entender tudo, e é fácil ficar perdido nas apresentações fora da sua área, mas mesmo assim dá pra aprender uma coisa ou outra. Mas é interessante ver os vários grupos tentando interagir entre si, tentando ligar as coisas, e engraçado às vezes, os conflitos entre teorias de várias áreas diferentes tentando explicar a mesma coisa. À noite, após o jantar e o término das palestras, havia uma segunda sessão de posters, mas com cerveja de graça. Eu que não sou fã de cerveja, bebia pelo menos umas duas long-necks por noite. Infelizmente não tinha nada do meu gosto. Tive que beber uma cerveja chamada UFO, que não é muito boa, mas eu tive que experimentar só por causa do nome.

Comi lagosta pela primeira vez na vida, e é uma tarefa árdua pra dizer o mínimo, pelo menos pra primeira vez. Tinha até um manual de instruções ensinando como fazer! HAUhUahUAHuHAuHAuhAa... Bom... Comi, e não gostei muito, mas valeu a experiência. Foi divertido aprender o processo. Duas das pessoas na mesa, desistiram de comer na metade, achando muito difícil, mas eu não desisti até o final, e cumpri a missão! Ha! Talvez eu demore um pouco pra querer comer lagosta de novo, mas não é tão ruim que eu não queira comer nunca mais. Só tem um gosto diferente...

O lugar onde foi realizada a conferência, Mount Holyoke College, é muito bonito também. Tirei algumas fotos que depois eu vou disponibilizar na Internet.

Possible error

Today I have discovered a possible error in the codes I use in my PhD studies. The error is in a subroutine that calculates the velocity gradients of the system. This program is being in use for almost 15 years, and no one has ever spotted this error. If I am mistaken, and I just have missed something, and in the end there is no mistake, excelent! Then life goes on... But, if I am not mistaken, and the error really exists, then the results already published using this program will have to be reviewed.

It is the second error I found in the codes. The first one, fortunately was in a function that was used only once over the program. After the change, the new results did not have any difference from the previous results. This second error was in a function that was called thousands, maybe millions of times, during the course of the program. The results after the changes were totally different from the previous ones.

I have showed it to my advisor, and she also thought that there was an error there. I have also sent an e-mail to my co-advisor in the US, reporting what I have found. She still did not reply... She was one of the people who wrote the program years ago, and use it ever since... I am just waiting her reply to be sure of the mistake, or to know that the mistake was mine... I just hope the mistake was not mine!

Waiting.

(...)

Return to work

Carnaval ended and now it is time to return to work. Return to my more-than-a-hundred-page program code. Reading and understanding all the physics behind that code is not so easy as I early thought. I guess I have passed already more than half of the code, but now I'm on the worst part, where we have all the physics, all the radiative transfer and line profile calculations.

Radiative transfer is one of the most beautiful physics's subjects, but it is also the most difficult subject that I have seen. For people who doesn't have any idea about what is radiative transfer, it is the study about how light or radiation propagates through a medium, including absorbtions, scattering, emission and re-emission of light due to atoms, molecules and dust throughout the medium.

There are a lot of simplifications in the code, concerning radiative transfer, but even so it is still not a simple thing. The magneto-hydrodynamics calculations, also done by the program, seems really simple compared with the afore mentioned one. And I tell you, magneto-hydrodynamics have nothing simple about it.

Magneto-hydrodynamics is the study of charged fluids in the presence of magnetic fields. It is also a fascinating subject, but also a very difficult one.

I just expect that someday I could understand properly both subjects. They are really fascinating!