Monday, June 26, 2006
With the solar cell strips from:
more than blimps are coming our way.
read more | digg story
Saturday, June 24, 2006
Kris Krogh has studied an alternative to General Relativity for several years now. He just published his most recent work to understand Active Galactic Nuclei.
I see a connection to Álvaro de Rújula's idea for a Theory of Cosmic Rays (cosmic rays note below). If Krogh's wave theory of gravity is correct, one should be able to predict properties of cosmic rays so far not observed and thus verify Krogh's ideas.
Wednesday, June 21, 2006
"We contend that we have identified the acceleration mechanism promoting the constituents of the interstellar medium of our Galaxy and others to become the bulk of the cosmic rays of all energies, and the 'magnetic-racket' accelerators themselves: the cannon balls emmited by ordinary core-collapse supernovae."
Thus ends the article by Arnon Dar and Álvaro de Rújula.
The authors claim that all Cosmic Rays observed so far can be understood with their cannon ball magnetic-racket model.
If true, this is a big accomplishment. The Auger Detector, half of which is already in Argentina, and the other half soon to be build in the United States of America, should have no problem in verifying this theory.
Saturday, June 17, 2006
Sunday, June 11, 2006
If you want all the formulas you will have to put some work, otherwise the book is useful.
read more | digg story
Wednesday, June 07, 2006
Sunday, June 04, 2006
I like this. I took it from Newsweek today.
Friday, June 02, 2006
But, there is always a counterpoint. I did not find a community of like minded people to grow intellectually here. They are not keeping my services, and I myself am not sure about my desire to stay. We parted in good terms, both with the students that loved the grades they got, and the faculty on staff, that were welcoming all along.
I am afraid I was more interested in sharing my passion for physics, than in actually making sure EVERYBODY got it. Even though I taught to three classes of gifted students, not everybody was equally interested in physics. I fail insofar as not making the subject interesting to all.
Thursday, June 01, 2006
I have considered for a long time how to teach modern physics at earlier stages of students academic life. There is a conceptual core related to the human experience with the Microworld and the Universe at large through particle accelerators, and different types of telescopes. As a species we know more about these realms than our predecessors just fifty or so years ago. The issue is then how do we communicate this knowledge to our children.
I start with a direct quote from Robert M. Wald's Resource Letter TMGR-1: Teaching the mathematics of general relativity. This letter appears in The American Journal of Physics, Volume 74, No. 6, June 2006.
"Gravity is not a "force" at all, but rather a change in space-time structure that allows inertial observers to accelerate relative to each other."
How does one go about "translating" that to a high school student?
The way I taught physics this year emphasizes that there are four known fundamental forces. Some students can repeat what I said, others cannot. I have not looked carefully at what they mean when they tell me that there are four fundamental forces, when they do tell me that. Right off, to use Prof. Ward's definition quoted above I have to change my introduction. I am afraid that there are many elementary school teachers that have to change even more what they say.
This note is just a first try on presenting that idea to young ones.
To begin with I have to state as clear as I can, what do I understand by that description. I believe Prof. Ward wants to separate gravity from the other three known forces; namely Electromagnetic, Nuclear Weak, and Nuclear Strong. In my mind I am tempting to paraphrase Ward in saying that neither of those other three are "forces" at all, but rather a change in internal space-time structure that allows inertial observers to accelerate relative to each other."
I am expressing here an speculation that is not only mine. There may be more dimensions to the Universe than the four we are used to; and there are mathematical ways to relate those extra dimensions with the internal symmetry groups associated with electric charge, nuclear strong charge, and nuclear weak charge. Even though this is speculation, it is not inconceivable that in the future humanity knows better the origin of all the "forces" of the Universe. Then what?, do they stop being forces, and turn into curvatures of ever more abstract spaces?
I do not know, but I agree with Ward that we should start talking to students more and more about what we do know about this Universe of ours. Unfortunately or fortunately we have to wait unitl ALL TEACHERS join the conversation. They cannot talk about what they don't know.
Education is our way to bring young ones into our conversations. I for one intend to keep the conversation alive.