Recent content by DrSirius

Well, if she is at 8.6 light hours from Earth at most, and she would be unlucky to recede from the Earth in the direction of the line connecting Earth-ship, depending on her speed it could take days and even weeks to contact her if we sent a signal right now. If we are lucky that she is coming...

What is the problem with 1950 approach? Relativistic mass? 3+1 dimensions vs 4D? Or more profound? Just curious.

I have a friend of mine which is an extraterrestrial. She travels in a ship around the Milky Way. She was likely in the Solar System, and she wants to attend tomorrow New Year's Eve at Plaza del Sol in Madrid, Spain. Her last communication was that she had faced a violent cosmic ray storm, and...

The book seems excellent. I am glad to have found about that example, it is the first time that I see, explicitly stated, that the question is not completely obvious or trivial. A teacher of mine solved it by printing a paper and fliping it the other side to show the symmetry. IMHO, that is not...

Yes, I see that and I think that I understand your point of view. However, if we go to the part of velocity composition, we could also check that "c + c = c" ( "+" is, in fact, the composition sign), but my point in this commentary is that it is not really necesary. With the paragraph that I...

I see, so it is a kind of "sanity check". But then all kind of paradoxes happen and you would need to check them one by one, so, once he proves that the proposition ( c being constant ) is satisfied, he can be sure that the theory is self-consistent? Could that be proved by simply mapping the...

Hi, I am reading the Einstein original paper on Special Relativity, in this link (English translation), I am having difficulties on this sentence: "We have now to show, that every ray of light moves in the moving system with a velocity c (when measured in the moving system), in case, as we have...