This article shows the posted discussions in Physics community of Orkut.
Can a Geophysicist become a theoretical physicist?Edit
2009y 2m 1dEdit
I don't know whether this question is meaningful or not. However, I want to ask it since it is somehow important for some students related to this question. The question is as follows. Is it impossible for students who are not good at mathematics or not interested in mathematics to be a theorist physicist?
speed of lightEdit
2009y 1m 10dEdit
Whenever the fundamental concept is questioned, usually somebody replys to read a associated page in Wikipedia. For example, as soon as the concept of 'group velocity' was asked, a member recommended to read a page in Wikipedia without his explanation. Thus, I now think that Wikipedia gives me similar feeling when I study Bible in my childhood. Whenever I asked an highly arguable question, my tutor teaches me referring to some pages in Holy Bible. It is not a good idea to say that Wikipedia is similar to Bible. However, the usage style of Wikipedia here looks sometimes quite similar to that of Bible. How about your opinion?
2009y 1m 8dEdit
Then, could you let us know briefly the difference between the group velocity and the phase velocity? You seem to emphasize a fact that the the group velocity is what we understand up to now.
2009y 1m 7dEdit
So, the better expression is the speed of the light is one of the fastest one in the world. Is it okay?
2008y 12m 27dEdit
How can we quantize wave? To average people, it looks impossible to depart wave in particles as we can not divide water in a river. I know that it has been a long time issue whether light is wave or photon. Eventually, Albert Einstein proved that light can be both of them based on the famous equation of E=mc^2 where E is energy and M is mass. It is true that the equation can not directly show that the light is both of them but the equation makes people understand the possibility of the transformation from one and to the other although the twos look fundamentally different. If somebody shows me some example how wave can be quantized, it will be appreciated.
2008y 12m 26dEdit
The sentence below is somehow not easy to understand.
'When any field is quantized, the interaction of the field with matter takes place by an exchange of a field particle.'said @velusamy.
Could you let me know the difference between matter and a filed particle. My understanding is as follows. If the size of particles is not very small, the field consisted of matter is a principle element to analyze else the field consisted of a field particle is a principle element. I think my understanding is week. So, please give me more explanation about the above sentence for my understanding.
2008y 12m 26dEdit
Although it has been discussed N number of times, the discussion for infinite speed or related topics should be lengthen until we have a concrete consensus about it. We are not here to re-study what we have learned from books of Physics in universities but we are here to find new theories by merging knowledges from the people who is living in many different places with many different environmental conditions. Although we can not find new theories breakable Relativity (E=mc^2), I'm sure that our human race will find new theories that we haven't imaged before in contemporary Physics. Any opinion?
MOON and earthEdit
2008y 12m 26d #1Edit
I still don't understand the relationship between the distance from the earth to the Moon and the mass distribution of the Moon (maybe related to mass of the earth as well). To my understanding, the distance is not strictly sensitive to the mass distribution of the Moon. Even if the distance come closer or go farther, we can not see the other side of the moon unless significant distance changing. I would be happy if someone clarify my understanding now. Thank in advnace.
2008y 12m 26d #2Edit
I know what you mean by the relationship between the self rotation and earth evolution rate of the Moon. Though I am not expert in Astronomy, I think the unequal mass distribution of the Moon protects the moon to change the face toward the Earth without seriously sensitive to the distance between the Moon and the Earth. It is similar to a situation that when we drop an unequal mass distributed material to the Earth. If the height is high enough, the position to face the Earth will be always a dense part, regardless the direction which one faced toward the Earth when he start to drop. Is my understanding still misleading?
ps. Could anybody let me know how I can find the threads which I involved in Orkut community forums? Currently, Even though I tried by my name (sungjin), I cannot find my threads. What's wrong with me?