Re: The velocity of light going pass a moving train.

Dono <sa_ge@xxxxxxxxxxx> wrote in
news:1182471434.117285.167600@xxxxxxxxxxxxxxxxxxxxxxxxxxxx:

On Jun 21, 12:58 pm, bz <bz+...@xxxxxxxxxxxxxxxxxxxx> wrote:
Dono <s...@xxxxxxxxxxx> wrote in news:1182450172.908373.143140
@a26g2000pre.googlegroups.com:

Correct, the beam hits the center for the train observer but does not
for the track observer. The reason is that the mirror has moved to
the right while the beam travelled from the floor to the ceiling.

You are ignoring the fact that the trackside observer MUST observe the
beam hitting the mirror in the exact same place that the observer on
the train sees it hit.


Why would that be, can you prove that the hit location is a frame
invariant?

MMX did that pretty well.

Name me ONE experiment that shows that the LOCATION at which a beam of
light hits a target is observed to be different by observers in different
frames of reference [or even by observers in different locations].

Parallax does not count as such an example because it involves seeing
objects at different distances, not objects at the same location.

Remember, our light pulse reaches the ceiling at the SAME location, each
time, as seen by the co-moving observer.

Take a bead on a rod, going from floor to ceiling. Bead moving up and
down rod at constant velocity of 1 ft per second. Train moving at 1 ft
per second.
rod ten feet long.

Bead travels 10 feet horizontally and 10 feet vertically in 10 seconds,
from trackside observers viewpoint.
Bead travels 10 feet vertically in 10 seconds from train observer's
view point.

Bead can not leave rod. Bead's velocity is different, as measured by
observer in train and trackside observer. Angle of path is different
for different observers. Bead still does not leave rod.

Same for light clock one light nano second tall.

But you are using a wrong analogy. The bead moves with the support,
light doesn't. You keep missing the fact that the train moves with
respect to the light trajectory. This is why , if the train side wall
were made of photographic paper, you would see a " tracer" like the
one coming from airplane machine guns) that is inclined from left to
right.

NO. The train's side wall is moving along with the ceiling and floor. The
trace on the wall would be a vertical line. Remember, the light moves in a
vertical line, as seen from the trains iFoR.

Light can not leave its vertical path, no matter if train is stationary
or moving at .999996 c.


Agreed. This is not the point of disagreement. The point of
disagreement is whether the "tracer" is inclined towards the front of
the train (you and Jeckyl) or its rear (me)

The trace is vertical as seen from the trains iFoR.
The light hits the center of the mirror.
The mirrors (or mirror and light source) move at the same speed.[the light
moves vertical as seen in the trains iFoR] so all observers in parallel
moving iFoRs must observe the light hitting the center of the mirror.



What varies is the TIME it takes to travel the path, and the length of
the path in the trackside observer's iFoR. The light still hits center
of top mirror. Different observers see the light move different
distances. Their clocks show different time for the transit. But all
measure the velocity of the light at c, using their own clocks, rulers,
etc.

--
bz

Again, no disagreement here, all observers measure c, observers
disagree on the amount of time, on lengths, etc.
The two of us disagree when it comes to the value of the aberration
angle, you claim it to be theta, I claim it to be 180-theta.

I claim it to be less than 45 degrees off of the vertical, inclined in the
direction of train motion.

I claim that the bead analogy is a very good one, only neglecting the
shortening of the train [as seen by trackside observers] as the train's
speed approaches 'c'. I claim that THAT shortening will make the beam more
close to vertical but that the beam will still strike the center of the
mirror.



--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+spr@xxxxxxxxxxxxxxxxxxxx remove ch100-5 to avoid spam trap
.

Relevant Pages

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