Recent content by Cosmology2015

Hello there! I am using a Surge Protection Device (SPD) for Solar Power System. My home uses a 3-phase system (380V and 220V at each phase). What should be the tension between the phase and ground at the SPD? And between the ground and neutral? Should be any tension at all? God bless all. PS. My...

Anyone?

It's a really interesting point of view. But if information decays over time would it mean that somehow the information is lost? It's possible? Do you know of bibliographical references on this topic? It's a very interesting subject! I would like to take the opportunity to wish you a nice week...

First of all I would like to thank you for your response! I had not paid due attention to the fact that one cannot take square roots of tensors. It really was a mistake. My general relativity knowledge is very limited, especially when it comes to the mathematics involved. How can I trace the...

Does anyone know of bibliographical references on this topic?

Consider the Einstein field equations in the form: ##R_{\mu \nu }-\frac{1}{2}Rg_{\mu \nu }=\frac{8\pi G}{c^{4}}T_{\mu \nu }## Now applying an appropriate conformal rescaling given by: ##\bar{g_{\mu \nu }}=\Omega ^{2}g_{\mu \nu }## Replacing in Einstein field equations gives the following...

Hello everyone! Before anything else thank you very much for the answers! I understand that to attempting any type of research, especially in areas such as general relativity and cosmology, would be necessary to have a training equivalent to that PhD students receive. It would be possible to...

Hello everyone! My goal has always been to be a researcher in physics. I am graduated in Electrical Engineering. My idea was to perform a master's degree and then a PhD, both in physics, with the aim of becoming a researcher. However, at this time I need to work, but I always have the night off...

Indeed! In fact, I wanted to express the fact that if the entropy increases as time passes then it means that the same decreases if one looks back in time. Again, you perfectly understood my question and I would like to thank you for your time. Despite my technical limitations, since I am still...

No problem! In fact, your answer was very enlightening and I am very grateful you have booked your time to answer it. I have another question that involves the second law of thermodynamics. The second law of thermodynamics states that the total entropy of an isolated system always increases over...

This idea is really very interesting. Could you tell me more about how to describe a system using conformal coordinates and how to calculate this relationship between the two times? Is there any reference (books, articles, papers, lectures notes) where I can learn conformal geometry applied to...

I would like to study more about the notion of time in modern physics. In particular, I would like to understand better the following question: how does one measure the time in the early universe? To measure time one needs to have clocks. A natural choice to be used as clocks would be particles...

Hello to all members! First of all, again, I would like to thank all the answers. These answers are very important to me as this is a matter that although I do not have the proper mathematical training, I have a strong desire to learn. I intend to study hard all references to try to understand...

Hello to all members! First, I would like to thank George Jones and PAllen for the quick response! With the answer that I was offered, although I do not have the mathematical training to study this subject at the moment, I could find out more about the subject. Wald's classic book on general...

Hello to all members! I heard on a documentary about general relativity and singularities that "energy is locally never negative". However, I was not able to get grasp the meaning of this term. Could someone explain to me the meaning of this term in the framework of general relativity. I really...