michel123456

Sorry in advance for the long post. This below is from your link: Now lets label the diagram in correspondance with the muons example: C=the earth's Frame Of Reference B= muon's FOR u=0.98c w=c Actually, from theory, we also know that [math]v=c[/math]. So we know almost everything. What we don't know is the gap between w and v. Following your precedent post, I suppose you are stating that the gap as observed in Earth's FOR is [math]w-u[/math] that is [math]c-0.98c=.02c[/math](1) Let's first make a simple check of the relativistic formula (just in order to make sure it is applicable here, people with knowledge can bypass this and go to point 2 directly) 1.Let's make the check. with: [math]u=0.98c[/math] [math]w=c[/math] inputting in [math] w=\frac{u+v}{1+uv/c^2} [/math] we get [math] c=\frac{0.98c+v}{1+0.98cv/c^2} [/math] [math] c(1+0.98v/c)=0.98c+v [/math] [math] c+0.98v=0.98c+v [/math] [math] c-0.98c=v-0.98v [/math] [math] 0.02c=0.02v [/math] [math] c=v [/math] Which was the expected result. The formula says that v, which is the gap in muon's FOR, is equal to the Speed Of Light. 2. But that was not the question. The question is what is the gap in Earth's FOR. Then we have to make the exact reverse calculations, labelling the same diagram as seen from the FOR of the muon: now the Earth is moving. We have the same graph with new labelling C=the muon's Frame Of Reference B= Earth's FOR u=0.98c There is no need to redo the calculations, see point 1. The result will be the same, since the input values are the same. The result is [math]v=c[/math] Which means that a scientist riding upon a muon can calculate that the gap in Earth's FOR is the Speed Of Light. 3.If we take as granted the result coming from simple substraction 0,02c see (1), and input this in the equations as seen from the muon's FOR, we have [math]u=0,98c[/math] [math]v=0,02c[/math] which gives [math]w=\frac{c}{1+(0.98c 0,02c)/c^2}[/math] [math]w=\frac{c}{1,0196}[/math] which is not an expected result. Theory states that [math]w=c[/math] in Earth's FOR. Michel

If TODAY there are beings out there 4 billions light years away , that are looking in the direction of the Milky Way, they are looking today at the Milky Way as it was approx. 4 billions years ago: it is in the past, we are not there, the planet Earth does not exist yet. If you mean that somebody from 4 billions light years away is looking at us as we are TODAY, it means that this somebody lies in our future, you cannot see him. In any way, we cannot communicate with somebody that is today on a planet 4 billions light years from us.

I suspect a bad translation. Dean probably wanted to say that all the people are the same. It is a fact that most of the time we put more importance to differences than to similarities.

Here I have to be really careful. Maybe I misinterpreted something. I suppose that in order to agree in the above statements, you must have made a substraction of speeds, stating for example that between 0.98C and 1C, there is a 0.02% gap, representing the muons (or Earth) chasing their own image. This gap is not observable inside a specific FOR, but observing from one FOR the other. Is it correct to make a simple substraction of speeds? Why not use the relativistic formula for composition of velocities?

Deleting my own comment after reading it.

(emphasis mine) Why "stable and constant particle"? One should expect that when opposite energies cancel each other, the result is null. Not something stable & constant, but zero. Do I miss something?

That is speed. That is spacetime. That is the barrier of speed of light. That is new*. It should mean that massive bodies in some manner must move through space continuously. It has been observed. "everything in the universe is moving.", Wikipedia 21st Century Τα Πάντα ῥεῖ, (Ta Panta rhei, everything flows) Heraclitus 535–475 BC *New from 3000 years ago.

(emphasis mine) Interesting comment. If (IF) gravity is an opposite kinetic energy, if and if, it means gravity is another form of kinetic energy, of opposite value. It means that what we experience as "rest mass" for example is not "at rest" but under the impulse of some "opposite" kinetic energy. It is not far from the equivalence principle that states that "the gravitational "force" as experienced locally while standing on a massive body (such as the Earth) is actually the same as the pseudo-force experienced by an observer in a non-inertial (accelerated) frame of reference." (italic from wiki Equivalence principle) "in an accelerated frame of reference"...

As stated before, there is relation between space & time. They may be considered "primitives", but they are related. It has been established that mass cannot move through space without spending time. There is a reverse statement that has not been established yet: mass cannot move through time without spending space. Read it three times.

I really apologize Iggy. You behaved correctly all along. I didn't. Mea culpa.

I stopped at the first sentence. No. He is not there to measure that. The only way he can do to measure the speed of light is to put a mirror where the red arrow is, and wait for light to reach him back. The light will have traveled 670 miles to go to the mirror 670 miles to come back at origin. 540 miles to go left Total 1880 miles in time: 1 hour to go 1 hour to come back at origin 0,8 hour to go left (approx 540/670=0,8059) Result 1880 miles/2,8 hours = 670 miles/hour Now the second sentence: Most probably, but he doesn't know that either. The only way to know is with a mirror, see above. He will get the expected result. Third sentence: No. Again he doesn't know that. He has to put a mirror where the red arrow stands. He will measure: distance for light 670 miles to go 130 miles to come back to him (670-540=130) total 800 miles time for light 1hour to go 0,2 hour to come back (approx 130/670=0,194) total 1,2 hour result 800/1,2=666 miles/hour approx 670 miles/hour. Elementary Newtonian calculations. All 3 observers will get the correct result. No. See above. Sorry Owl far having responded in your place. ----------------------------------------- I really wonder how dumb you think we are. ----------------------------------------- You should ask yourself how dumb we think you are. ------------------------------------------ Sorry, I am pissed for other reasons.

There is a physical relation between distance and time. Physical I mean, not philosophic.

Tell us more.

An example from another thread: There should be a sticky on how to make a good paper, or at how to avoid basic mistakes. Is there any?

Good question. There is a procedure when coming to very basic question. It is to make it even simpler, to reduce to minimum, then to ask again. Following standard theories, space is not alone, there is a spacetime continuum of 4 dimensions. The procedure consists to eliminate as many dimensions possible. From the x,y,z,t dimensions, you can easily get rid of some. Consider a point object moving along a straight path, you need only x & t, y & z are redundant. The remainings x & t, these are distance & time. So the question of "what is space" can be reduced (??) in a more complicated double question: what is distance and what is time? Well, because "what is time" was not part of the opening question, and it is too difficult to get any straight answer, you may avoid to go into this part. The question is then "what is distance"? Keeping in mind that the answer must involve time somehow, because time & space are intricated, and not answering simultaneously the question "what is time" was basically an error.

O.K. now I understand what you ment in post #34. Thank you both Swansont & Sisyphus. But the only direct measurement we can make is in our own FOR, from light moving at C hitting some measurement device. We cannot directly measure the speed of light relative to another FOR. The only thing we know for sure is that the other observer in its own FOR will also find the same value for C. What you propose, if I understand well, is that from our FOR here on Earth, we have to consider that the spaceship approaching us at 0,5 C under constant linear motion is chasing its own image. We can imagine the same situation in reverse, saying that for some supposed alien planet, the Earth is chasing its own image because the Earth approaches the alien planet at 0,5 C. Did I make any mistake in the above statements?

See what I mean?

My proposal was intended to avoid the molecules analogy. Einstein struggeld so hard to erase the concept of aether, but those molecular anologies make it come back, I am afraid. Although the space expansion concept does not support necessarily the aether theory, all analogies are based upon some material background (a balloon, a cake, water molecules,...) that make people believe that "something" is expanding or "created".

Has your question a relation with this thread?

What are we doing when measuring the speed of light coming from the stars?

Now I don't understand your post #38 Aren't the stars around us moving relatively to us?

I wonder. Instead of talking about "space expansion" which makes people believe that "something" is expanding, why don't we introduce a second kind of motion, a "motion-that-is-not-motion", call that s-motion, that simply does not correspond to standard laws of motion? But corresponds to some other universal law.

I don't understand your post #34 Interrogation point bolded.

The light that comes from all stars of the universe don't reach the Earth at C ?

That is very Newtonian. The speed of light minus the speed of the Earth.