Re: Are *observed* SR effects real?

On Jul 24, 6:19 am, mluttg...@xxxxxxxxxx wrote:
On Jul 23, 6:31 pm, PD <TheDraperFam...@xxxxxxxxx> wrote:



On Jul 23, 11:08 am, mluttg...@xxxxxxxxxx wrote:

On Jul 23, 5:06 pm, PD <TheDraperFam...@xxxxxxxxx> wrote:

On Jul 23, 8:48 am, mluttg...@xxxxxxxxxx wrote:

On Jul 23, 1:36 pm, PD <TheDraperFam...@xxxxxxxxx> wrote:

On Jul 23, 6:19 am, mluttg...@xxxxxxxxxx wrote:

You have been contradicting yourself!
You agreed that the domain of applicability of SR is limited
to 'inertial' frames.

Please pay attention to what I actually said. What I said is that
there are many frames that are not *absolutely* inertial, but in which
the non-inertial effects are much smaller than the effect being
measured and are therefore negligible (where "negligible" literally
means "can be neglected").

Iow, you agree with what I wote:

"Claiming that nothing changes physically when the Earth moves
wrt the plane is wrong, because the Earth is gravitationally
linked with the Sun (neglecting the Galaxy, and even the whole
Universe), and you should know that SR cannot be applied
in gravitational fields."

No, I don't agree with it. Please read what I wrote about the
equivalence principle, which is one of the underlying bases of GR.
<
I wrote: "you should know that SR cannot be applied
in gravitational fields", and suddenly, you jump
to GR! Does that imply that SR also applies (nothing
coming from SRists can surprise me, even bad faith)!

Please pay attention. I told you where to re-read. Since you are
incapable of doing that, I will repeat myself.

One of the backbone principles of GR is that any sufficiently small
laboratory in free-fall (that is, IN A GRAVITATIONAL FIELD) is
indistinguishable from an inertial frame of reference. So, yes,
special relativity can be applied even where there is a gravitational
field as long as the tidal effects due to gravity are much smaller
than the other effects (including ones predicted by special
relativity) being measured. Furthermore, you made the earlier
incorrect statement that special relativity cannot be used where there
is acceleration. That is also incorrect.

Where did I claim that SR can't be used where frames are
accelerating?

My point is that SRists too often forget physical reality:

Here are a few examples:

- The Earth is rushing toward cosmic muons (Paul B. Andersen)
   This is physically nonsensical, because the Earth is
   gravitationally linked to the Sun, etc...

You misunderstand apparently. The suggestion is not that the Earth is
rushing toward cosmic ray muons and leaving the Sun behind. The
suggestion is that the Earth *and* the Sun *and* the galaxy the Sun is
gravitationally linked to is rushing toward the muon. There is nothing
wrong with that statement. As a reminder of this, observationally *and
physically* other galaxies are in general receding from our own (see
Hubble and what he's most famous for). Now, in what sense can you pick
out whether it is the others that are receding from ours or ours that
is receding from the others, and more importantly, is there any
*physical* distinction that is important?

- One cannot tell from 600 mph relative motion between
   the Earth and a plane, whether it is the plane that's moving
   or the Earth that's moving (PD)
   The Earth is rotating, for instance at 600 mph at some
   latitude. At such latitude, a plane whose ground speed is
   zero has an 'air' speed of 600 mph, as any pilot would
   confirm.

Well, actually no. If the air is still with respect to the ground, the
air and ground speed would be both 600 mph. But the speed of the plane
with respect to a line through the centers of the Sun and the Earth
could well be zero.

- It is not possible to know if a train is moving, without
  'looking' outside the train.
  This is false, as a train follows the curvature of the Earth,
  and is consequently subject to an acceleration a = v^2/R,
  where R is the Earth radius. When v is small, 'a' can be
  neglected, and SR approximately applied.
  But when v is a not negligible fraction of c, like is many
  SR thought experiments, 'a' becomes enourmous.
  For instance, with v = 0.1 c, 'a' is about 1.5*10^10 cm/s^2!
  Using such big velocities in a SR thought experiment is
  physically nonsensical.

And no such huge speed was implied. As I already mentioned to you, H&K
performed their experiments at speeds much, much lower than even
0.00001c.

PD

- Etc, etc, etc ...

Marcel Luttgens



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