michel123456

I thought relativistic composition of velocities was valid only between FOR. It seems to me your answers differ from thread to thread.

So you have to find the source first? In this case you need other kind of data. Relief map and geological. It is getting complicated. If it is an autonomic system for the village, a political map showing the village district is a must.

I think you are making things too complicated. Stick to your question, do not amplify it. In real world, you should begin by making a market research, make a feasibility study, find investors, create a society, get authorizations and a lot more that were not asked. Read the question, ask the question, proceed.

Did I say that? I suppose. I still cannot swallow: _that c-0,98c=0,02c is correct, even in a single FOR. _that 0,98c + 0,02c= c is correct, even in a single FOR (that must be my error) _that the result 0,02c has a physical meaning. _that the meaning is that the muon is "chasing its own image", as observed from our FOR. Since in its own frame, the muon is not "chasing its own image" _that it is necessary to make different diagrams (animations) in order to explain one single phenomenon, each one from a specific FOR _that those diagrams do not present the same physical result, as I understand. What I could swallow is that all observers are not measuring the same "thing".

Well that was not very clever from LightHeavyW8 to think that an object traveling at 0,7c will go faster than c. I hope I am not that bad... I am not arguing in favor of superluminal velocity, quite the contrary. Nice work from Janus, indeed.* Still thinking, that Iggy showed the speed of the reduction of a distance which was part of the definition of the speed. That is the rate at which a distance between 2 different objects diminishes as observed from a third. The fact that the 3 objects are aligned is just a special configuration. If there were 60 objects placed radialy around the observer, all rushing to him, what is the physical meaning of the sum of 60 distances and the rate they diminish (that can be many times the speed of light, if the 'objects' are light rays)? I feel misengaged. What i wanted to say previously, but Iggy's post cut my enthusiasm, is that the formula of relativity for compositions of velocities can always replace the Newtonian (Galilean) one. Relativity is more precise, it is never wrong. Now I have to think about it again. Maybe Newton wins... *but the animation shows only what happens following the FOR of the point where the light source originated. IMHO. Because a light ray emitted one second after departure, from the left object (his own image for example) travel much faster, as seen by the object. That is another animation. editing: oops, Janus explained everything in post #42 of the same thread.

I changed my mind. It seems you give an example where relativistic summation does not apply, Iggy. At first glance I wonder with 3 or 4 objects, what the summation of distances between them would physically mean, but with 2 objects you made a point. I have to think about it. from mathpages.com And the whole chapter after.

Maths agree with me. I am at point B An object A approaches me from the left at 0,9c Another object C approaches from the right at 0,9c Then the 2 objects approaches at ...1,8c? But: Me, at point B don't observe anything moving at speed 1,8c Object A don't observe anything moving at speed 1,8c Object C don't observe anything moving at speed 1,8c No object, no wave, nothing propagates at 1,8c. Nothing from nowhere moves at 1,8c. Nothing is observed at 1,8c. The result 1,8c is a physical nonsense. The result 1,8c is wrong. If you want to add 2 velocities, you must use the relativistic formula. Only then the result will have a physical meaning. That's it. I quit.

0,98c+0,02c 0,5c+0,6c 0,45c+0,67c 0,95c+0,95c are all answerable without any problem, without "if" this or "if" that. These are not ill-formed questions. Relativity states very clearly that simple summation of velocities is wrong. In any case.

I am not sure having seen spambot on this forum. Most are spammers, I mean there is an individual behind the post, no robot. If it is the case, no matter what you do, they will always find a way to annoy. That's their job.

I understand the animation. Look. Someone said, if muons go at 0,98c in Earth's FOR, then the remaining c-0,98c=0,02c in Earth's FOR, because it is all measured in the same FOR. If a child is coming to you and ask you the result of 0,98c+0,02c What is your answer?

Ididn't read anything of the other posters. I would like to hear Voltman's point.

If you make a catalog of gaps today, and compare to a catalog of gaps of the 19th Century, you will see that the catalog has increased. That is because the answer of one gap raises more than one question. IMHO the gaps are the ocean, and the answers are some boats with scientists.

http://www.techdirt.com/articles/990903/0643219.shtml see post 25. Achmad is invading the web with his kidney.

You're welcome. Besides, I don't consider myself as a reliable source, so you may be right and I may be wrong. Keep asking.

Of course they are different. But they must extract the same conclusions about the Universe. Exactly. We agree. So why do you all believe that the rocket is "chasing" light? It is not, not even in the first animation. You cannot make the substraction c-v just like that, because c-v=c, always. That's the point: it has a velocity of c no matter what. It is obvious.

No. It doesn't make sense that the 2 diagrams are different either. IMHO what happens is the following: _in the first animation, you made a velocity addition, a substraction actually. It is not different than a statement in which you say that 0,6c+0,6c=1,2c: it is wrong. You should have used the relativistic formula, although remaining in the same FOR. _the same goes for the second animation. You made there a clearer velocity addition in a newtonian way. The result is that light escapes from Earth at superluminal speed: it must be wrong. You should have used the relativistic formula in which no speed can attain SOL. If you do that for both animations, the 2 diagrams will give the same result, and this thread come to an end. The other way is to send me to the asylum.

Sure you can.

These are 2 diagrams representing only one phenomena. Iggy may use lorentz transformations at will. I would like to see that.

Don't figure anyone understands profoundly the existing Theory. The BB Theory states that the "singularity" happened "everywhere". IIRC even the term "singularity" is under reconsideration. I am not an advocate of the Big Bang, ask someone else, there are plenty of experts on the subject here. What I can advocate is that on my own sketch above, point C cannot observe point A. That was solely intended to answer your question. I apologize if I made things more unclear than they were.

Quoting Thank you for the animations. They show what I was afraid of when saying The 2 diagrams are different in length. At t=10, the distance between the Earth and the ray of light are different, small in the first diagram, long in the second. Since we are talking about the same and only one phenomena, how is it possible? Can you make some other diagrams showing at the end the ray of light at the same distance no matter the FOR?

I am. Now take C as the Earth, B the muon, and A the ray of light. Where upon the diagram is v that has been calculated from the muon's FOR ? I don't know if we are communicating properly. What is measured from one FOR must correspond to the other, it is a single phenomena, either observed from earth, either from the muon. When the muon calculates what is experienced in Earth's FOR, it must be what is calculated by Earth's FOR. v is v. Unless you tell me that v in one FOR is w in the other, and vice-versa. That is the reason why I 'll ask you to show me upon the diagram where is v in Earth's FOR (the value you say is 0,02c), as calculated by the muon (=1c), when C is the Earth.

Something like this? trying to go into your mind: We are at point C. The BigBang happened at point B All events on the circle have the same age. Maybe we are looking at event A that has the same age with us. No. First of all, the Big Bang, following the Theory, did not happened in a particular place. There is no specific central point B. Secondly, all we see around us lies in the past. That is because the Speed Of Light has a particular finite value: when an event is far away, light must have spend some time before reaching us. The "time that was spend" is another way of saying that the far away events are in the past. Even if there were a point B from which the universe originated, our visibility would end there. In fact we would observe concentric circles of events from the past, the most ancient events being in the little central circle at point B.

You are confusing v and w IMHO. The muon's frame calculates v in Earth's frame. Please show me on the first diagram where is v in Earth's frame. On this one

Look I am getting completely nuts. In BOTH Frames, w=c, u=0,98c because it is totally symmetric. The result of the relativistic equation gives the result that is measured in the other frame. The result is c, not 0,02c.

3c/2 = superluminal. Is that allowed? that's what i have done in point 3: C is the muon's FOR The muon measures u=0,98c w is measured in the muon's FOR w=c v is measured in Earth's FOR v=0,02c (on your assumption) the result is inaccurate.