Re: Neutrino Mass and Supernovae

From: Ken S. Tucker (dynamics_at_vianet.on.ca)
Date: 09/20/04 

Date: 20 Sep 2004 10:39:40 -0700

Bjoern Feuerbacher <feuerbac@thphys.uni-heidelberg.de> wrote in message news:<cimatc$50e$1@news.urz.uni-heidelberg.de>...
> Ken S. Tucker wrote:
> > Bjoern Feuerbacher <feuerbac@thphys.uni-heidelberg.de> wrote in message news:<cik01t$jkd$1@news.urz.uni-heidelberg.de>...
> >
> >>Ken S. Tucker wrote:
> >>
> >>>Bjoern Feuerbacher <feuerbac@thphys.uni-heidelberg.de> wrote in message news:<cih7dg$360$1@news.urz.uni-heidelberg.de>...
> >>>
> >>>
>
> [snip]
>
>
> >>So, if you do *not* think that charges can exist independent of
> >>particles, why did you object above when I said "particles" instead
> >>of "charges"?
> >
> >
> > It's important to not import into the scenario *mass* that's attendant
> > with the concept of particle.
>
> I don't think that mass is an attendant with the concept of particle.
> E.g. photons are particles, but they have no rest mass.

Good example, thanks.
 
> >>> We are in reality because energy
> >>> exists only when charge couples exists.
> >>
> >>Please elaborate.
> >
> >
> > A single charge has no independant reality,
>>(proof: clap with one hand:)
>
> How does that prove that a single charge has no independent reality?

You can stop clapping now :)
 
> > Charge is relative, as velocity is relative.
>
> No, charge is not "relative" (in the sense that charge makes only sense
> if another, different charge exists), since the field of a single charge
> already has energy.

No, that's an old wive's tale, a single charge has no energy.
 
> > Charge is invariant, as "c" is invariant.
> >
> > Relativists have no problem accepting "c" is invariant but c is a
> > velocity and velocity is relative. Apply that reasoning to charge.
>
> False analogy, I would say.

> >>>>>Hence the negative mass may have a velocity "v",
> >>>>
> >>>>You use the Schwarzschild metric for the object with negative mass.
> >>>>But the Schwarzschild metric is for an object which is *resting*.
> >>>>So how does that tell us anything about at which speed this object
> >>>>could travel?
> >>>
> >>>
> >>>The term "resting" is meaningless in relativity.
> >>
> >>No, it isn't. It is not *absolute*, but it is not *meaningless*.
>
> No comment?

Why, we would be discussing semantics. What I think is important
- to distinguish relativity from any and all allowed motion - is
the vanishing of *absolute* motion. I accept the definition as,

   U_i U^i = 0 (U^i is 3 velocity).
 
> >>>more specifically SR "implies" velocity cannot exceed
> >>>the local speed of light, which in this case is C>c.
> >>
> >>Please provide a proof that SR implies that velocity cannot exceed
> >>the ***local*** speed of light. As I said above (apparently you missed
> >>that), I thought that SR says that velocity cannot exceed c! (not C!)
> >
> > Cerenkov radiation, look it up.
>
> Err, Cerenkov radiation once again proves *my* point, not yours!
>
> Cerenkov radiation happens when an particle flies with a velocity
> *greater* than the *local* speed of light (C, in this case C < c)- but
> still *slower* than c!!!
>
> So Cerenkov radiation shows that the speed limit is *not* the *local*
> speed of light (C), as you keep claiming, but simply c!

Cerenkov radiation is bit more complicated than that. Recall
a refractive index depends on frequency of EMR, Blue is "slowed"
more than red in glass (chromatic aberration). The actual effect
for a particle depends on variations on the atomic level of the
local speed of light. IIRC there C is not exceeded.
 
> Please prove your point that SR says that the speed limit is the local
> speed of light (C), not simply c.

That's the basis of GR. SR is a limit at any point in a g-field
and the local speed of light there is c. But that's C when measured
globally, we're back to Shapiro.
 
> Bye,
> Bjoern

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