Prev: ~~~ BIG IDEA~~~ click here
Next: PD has questions about science. Can any of you help?
From: PD on 24 May 2010 08:34
On May 23, 4:39 pm, GogoJF <jfgog...(a)yahoo.com> wrote:
> On May 23, 7:32 am, "Inertial" <relativ...(a)rest.com> wrote:
>
>
>
> > "GogoJF" <jfgog...(a)yahoo.com> wrote in message
>
> >news:b3a81403-ba25-49d2-81ca-1dd00f8d1d4e(a)z33g2000vbb.googlegroups.com....
>
> > > On May 18, 8:10 pm, "Inertial" <relativ...(a)rest.com> wrote:
> > >> "GogoJF" <jfgog...(a)yahoo.com> wrote in message
>
> > >>news:abe719f4-dc60-42ba-a33d-d211e6df2bfb(a)q8g2000vbm.googlegroups.com....
>
> > >> > What is the meaning of c?  Whether one believes that light is finite
> > >> > and constant and travels at c- or whether light is to be believed to
> > >> > be instant-
>
> > >> It isn't .. because we can measure that it isn't .
>
> > >> > is regardless- because the reason why the speed of light c
> > >> > travels at 300,000 km/s and not 200,000 km/s, or 100,000 km/s is a
> > >> > separate issue.
>
> > >> > Why this particular speed of c?
>
> > >> Because that is what it is.  It doesn't need a reason to be that way.
> > >> Its
> > >> purely determined by human choice of units.  In 'sensible' (or natural)
> > >> units, c = 1.
>
> > >> > 1)  Is this merely the limit of man's measurably?
>
> > >> Nope
>
> > >> > 2)  Is there some indication of c on a planetary or stellar scale, in
> > >> > terms of our inertia?
>
> > >> Nope
>
> > >> > 3)  Is this speed human friendly?  In other words, would we as humans
> > >> > be different if c were a different constant speed?  Would we be the
> > >> > same if c were not constant?
>
> > >> The universe would be totally different is there were different 'laws' of
> > >> physics .. but asking what people would be like in that case is pure
> > >> guesswork.
>
> > > Whether one believes that light is finite
> > >> > and constant and travels at c- or whether light is to be believed to
> > >> > be instant-
>
> > >> It isn't .. because we can measure that it isn't .
>
> > > Just remember inertial, when you look up at the stars and believe that
> > > you are looking at objects that are millions of years into the past-
> > > that you are the one who believes in sante claws.
>
> > No .. I'm someone who understand the wealth of information that supports
> > finite speed of light . there is no evidence that it is infinite.
>
> http://en.wikipedia.org/wiki/Speed_of_light
> Wiki says:
> 1.  The speed of light is the speed of all massless particles and
> associated fields in vacuum, and it is believed to be the speed of
> gravity and of gravitational waves and an upper bound on the speed at
> which energy, matter, and information can travel.
>
> 2.  For much of human history, it was debated whether light was
> transmitted instantaneously or merely very quickly
>
> 3.  More generally, it is normally impossible for any information or
> energy to travel faster than c. One reason is that according to the
> theory of special relativity, if something were travelling faster than
> c relative to an inertial frame of reference, it would be travelling
> backwards in time relative to another frame,[Note 5] and causality
> would be violated.[Note 6][30] In such a frame of reference, an
> "effect" could be observed before its "cause". Such a violation of
> causality has never been recorded,[14] and would lead to paradoxes.
> [Note 7][31]
>
> 4.  In some interpretations of quantum mechanics, certain quantum
> effects may seem to be transmitted faster than c—and thus
> instantaneously in some frame—as in the EPR paradox.

No. There is no *transmission* of any effect greater than c.
This is a basic misunderstanding of quantum entanglement.

>
> 5.  If the particles are separated and one particle's quantum state is
> observed, the other particle's quantum state is determined
> instantaneously (i.e., faster than light could travel from one
> particle to the other).

Yes, and there is no signal transmission that is involved. This is
precisely where Einstein was proven wrong. His instinct told him to
respect the principle of locality -- that two spatially separated
objects HAD to communicate via transmission for there to be a
correlation in behavior. Quantum mechanics says otherwise: that two
spatially separated objects may nonetheless comprise ONE quantum
state, and that a state transition does not in any way constitute a
signal transmission from one object to the other.

>
> 6.  Another quantum effect that predicts the occurrence of faster-than-
> light speeds is called the Hartman effect; under certain conditions
> the time needed for a particle to tunnel through a barrier is constant.
> [35][36] This could result in a particle crossing a large gap faster-
> than-light.

Again, there is no *crossing* of the gap performed by the particle.
The particle's wavefunction lives on BOTH sides of the gap, and so the
object itself lives on both sides of the gap, quantum mechanically.

>
> 7.  As is discussed in the propagation of light in a medium section
> below, many wave velocities can exceed c. For example, the phase
> velocity of X-rays through most glasses can routinely exceed c,[38]
> but such waves cannot convey any information.[39]

That's correct. No signal can be conveyed faster than c.

>
> 8.The rate of change in the distance between two objects in a frame of
> reference with respect to which both are moving (their closing speed)
> may have a value in excess of c.

Yes, this is so, but this in no way violates the cap on the speed of
an object in a given reference frame.

>
> 9.  So-called superluminal motion is seen in certain astronomical
> objects,[40] such as the relativistic jets of radio galaxies and
> quasars.

So-called superluminal motion is an effect that gives the *appearance*
of motion that is not really there.

From: BURT on 25 May 2010 16:30
On May 23, 10:22 am, Igor <thoov...(a)excite.com> wrote:
> On May 22, 6:52 pm, BURT <macromi...(a)yahoo.com> wrote:
>
>
>
>
>
> > On May 22, 9:57 am, Igor <thoov...(a)excite.com> wrote:
>
> > > On May 21, 10:59 pm, BURT <macromi...(a)yahoo.com> wrote:
>
> > > > On May 21, 3:03 pm, "Androcles" <Headmas...(a)Hogwarts.physics_z> wrote:
>
> > > > > "Igor" <thoov...(a)excite.com> wrote in message
>
> > > > >news:58d440b8-92df-4599-866b-4669090c83f3(a)j27g2000vbp.googlegroups..com...
> > > > > On May 18, 4:20 pm, BURT <macromi...(a)yahoo.com> wrote:
>
> > > > > > C is the speed limit. There is nothing faster to measure.
>
> > > > > > Mitch Raemsch
>
> > > > > Wrong, photon breath!  There are things that can be "measured" to be
> > > > > moving faster than c.  Phase velocity for one.  But so far, no one has
> > > > > ever demonstrated that information can be transmitted faster than c.
> > > > > ===============================================
> > > > > Yes I have. You'll go on repeating your mantra with your head buried
> > > > > in the sand.
>
> > > > I don't believe in phase velocity. That is made up.
>
> > > That doesn't surprise me, since a student in kindergarten understands
> > > more about physics than you do.- Hide quoted text -
>
> > > - Show quoted text -
>
> > Phase velocity has no basis in reality.
>
> Neither does your mind.  Forget about physics and take up remedial
> basket weaving.- Hide quoted text -
>
> - Show quoted text -


Phase velocity is anti Einstein. He would have nothing to do with it.
It is a mistake.

Mitch Raemsch
First  |  Prev  | 
Pages: 1 2 3 4 5 6 7
Prev: ~~~ BIG IDEA~~~ click here
Next: PD has questions about science. Can any of you help?