Re: Are *observed* SR effects real?

On Jul 21, 4:18 pm, PD <TheDraperFam...@xxxxxxxxx> wrote:
On Jul 21, 7:37 am, mluttg...@xxxxxxxxxx wrote:





On Jul 21, 1:36 pm, PD <TheDraperFam...@xxxxxxxxx> wrote:

On Jul 21, 3:34 am, mluttg...@xxxxxxxxxx wrote:

On Jul 21, 4:02 am, PD <TheDraperFam...@xxxxxxxxx> wrote:

A simple experiment shows that the train, not the ground,
is moving :
Tom used a spring scale on the ground. He put an object
on the scale, and found some weight w0.
On the train, he uses the same very precise spring scale.
If he measures w1 < w0 for the same object, he is *certain*
that the train is moving.

Why, Marcel, I'm astounded you still think it is possible to tell if
you are at a higher or lower absolute motion than in another frame.

Tell me, Marcel, in the plane flying east to west over a rotating
earth at 600 mph, what do you think the precise scales will show, and
why? And does this depend on whether it's noon or midnight? (Think
about where the plane is and what direction it must be going, relative
to the earth's motion in each case.) And does this depend on what time
of year it is? (Think about where the plane's direction will be,
relative to the solar system's motion relative to other stars.)

If I have *two* trains going by each other on *flat* tracks (not
following the curvature of the earth, but following a chord), do you
think it is possible to tell which one is going faster than the other
through space?

But trains do follow the curvature on the Earth!

Oh, dear. So Marcel, what do you think the answer is about the plane
that is flying east to west at 600 mph, hovering (at least in terms of
the sun-earth frame) in space while the earth rotates under it? Is the
plane *really* moving, and how can you tell?

What would do a plane whose engine cease working?


And Marcel, you do realize, don't you, that we could have done this
whole exercise with Tom on one train and Stan on the other, with the
poles being on Stan's train and the brushes on Tom's train and filling
some other purpose, and the results of the simultaneity of the flashes
would have been exactly the same?

Finally, Marcel, if it wasn't clear, though virtually all reference
frames have either the effect of gravity or are falling some curved
trajectory in practical reality, it is also the case that in practical
reality many of those frames can be treated as inertial if the tidal
effects (read "non-inertial") are small enough to be ignored in the
measurement being taken. Small tidal effects are not the way to
determine which reference frame is the one that is "really" moving
(though it might provide some insight as to whether one of the frames
is in non-inertial motion).

A falling plane will reach the Earth with some
velocity vp, that can be calculated from its initial
height and the Earth's gravity.
Do you think that such plane can be considered as
being 'at rest', and the Earth is falling towards
the plane. Then calculate the velocity ve of the Earth
when it crashes into the plane. Do you think that
ve = vp?
Note that according to Newton's 3rd Law, the Earth
itself experiences an equal and opposite force to
that acting on the falling object, meaning that the
Earth also accelerates towards the object. However,
because the mass of the Earth is huge, the acceleration
of the Earth by this same force is negligible, when
measured relative to the system's center of mass.
(cf. Wikipedia, http://en.wikipedia.org/wiki/Gravity#Earth.27s_gravity
).
But SRists neglect Newton's 3rd law, and in fact,
all physical laws. They live in a very pecular world,
in which all frames are hypothesized to be 'inertial',
or practically inertial. For instance, in their thought
experiment, a train can move at 0.3 c without leaving
the rails!

Marcel Luttgens



Do you have any further comments or questions?

PD





Marcel Luttgens
.

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