Re: [SR] The traveler of Tau Ceti

Le 27/03/2024 à 17:07, Volney a écrit :

On 3/27/2024 8:25 AM, Paul B. Andersen wrote:

Den 27.03.2024 07:23, skrev Richard Hachel:

It appears "Dr." Hachel stumbled across the physics concept of "rapidity". Rapidity is related to speed but isn't a speed. It is related to speed by r = arctanh(v/c) where v is the velocity. The rapidity of light is infinity. AFAIK, rapidity is used sometimes to simplify the math. For example, rapidities of two objects in one dimensional motion can be just added but velocities need the Einstein velocity addition formula.

Your answer is very interesting, I will just modify it slightly.
You say that for Doctor Hachel the notion of real speed is not a speed.
Of course yes, and it's even the only consistent speed.
This is the usual notion of observable speed Vo which is NOT a speed but a simple decoy.
This is also why relativistic speeds do not add up as one could do in the case of Newtonian speeds.
I have given all the formulas that must be used in relativistic physics, including in uniformly accelerated media and rotating media, including many things different from what physicists say, but with much more clarity and coherence than them.
You are talking about additions of observable (measurable) speeds, the formula is here:
<http://news2.nemoweb.net/jntp?imChwfC2KmQA4gQfMNTxoMdVOMA@jntp/Data.Media:1>
As for real speeds, the addition is not simpler,
because we add a real speed in one frame of reference, and a real speed in another frame of reference. The formula is here:
<http://news2.nemoweb.net/jntp?imChwfC2KmQA4gQfMNTxoMdVOMA@jntp/Data.Media:2>
I remind you that physicists who say that real speeds are of no interest are wrong. On the contrary, these speeds are of great interest when the problems become more complicated, and when applying reality becomes more useful than applying the observable.
R.H.