Re: Basic Relativity Question from a Beginner

On May 29, 2:30 pm, PD <TheDraperFam...@xxxxxxxxx> wrote:
On May 29, 8:07 am, Albertito <albertito1...@xxxxxxxxx> wrote:



On May 29, 1:49 pm, PD <TheDraperFam...@xxxxxxxxx> wrote:

On May 29, 7:35 am, Albertito <albertito1...@xxxxxxxxx> wrote:

On May 29, 1:15 pm, PD <TheDraperFam...@xxxxxxxxx> wrote:

On May 29, 7:05 am, Albertito <albertito1...@xxxxxxxxx> wrote:

On May 29, 12:59 pm, PD <TheDraperFam...@xxxxxxxxx> wrote:

On May 29, 6:48 am, Albertito <albertito1...@xxxxxxxxx> wrote:

On May 29, 12:10 pm, "Dirk Van de moortel" <dirkvandemoor...@ThankS-NO-

SperM.hotmail.com> wrote:
ken.ger...@xxxxxxxxx <ken.ger...@xxxxxxxxx> wrote in message

5efb11cf-479c-4b25-99c7-12e1fa82a...@xxxxxxxxxxxxxxxxxxxxxxxxxxx

My friend and I need a little help with a thought experiment. Any
input is appreciated.

Situation:
My friend and I each start at point A. At the same instant, we start
traveling at 60% the speed of light. He in one direction; me in the
exact opposite direction. After a certain amount of time, he shines a
flashlight back in the direction of our starting point (and me).

Questions:
Can I see the flashlight?

Yes.
Well... sort of. See below.

If so, what color is it?

:-)
See below.

What is our relative velocity to each other?

That would be
( 0.6 + 0.6 ) / ( 1 + 0.36 ) percent of light speed ==> 88%

The wavelength of the light you friend shone, divided by
sqrt( (1 - 0.88 )( 1 + 0.88 ) ) = 0.064
So if he shone a blue laser with wavelenght 473 nm, you will
get a signal with wavelength 7400 nm, which is somewhere in
the infrared.
So you won't really *see* it after all :-)

Dirk Vdm

Dear Ken and friend, both of you are moving at
60% the speed of light in opposite directions wrt
the starting point, that's not good for two good
friends, is it?

Anyway, your relative speed is v = 60% + 60% = 120%
percent of light speed.

For the OP, this is an example of the crap you will find on UseNet.
Asking questions here comes with the burden of having to sort out the
gold from the crap.

The wavelength of the light you
friend shone, divided by Exp(-1.2) = 0.301. So if he shone
a blue laser with wavelenght 473 nm, you will get a signal
with wavelength 1570 nm, which is somewhere in the infrared.
So you won't really *see* it after all :-)

Hey fuckhead, prove that my calculations are wrong!

That's not necessary, you dwip. Your posting nonsense does not present
the necessity to demonstrate that your nonsense is nonsense. Dirk's
numbers come from a model that has been demonstrated to be consistent
with experiment. Your numbers come from a model that has been
demonstrated to be inconsistent with experiment. That experimental
information is freely available in the literature to anyone that wants
to look it up, but that does not mean that the information should be
reproduced in ASCII here.

You are certainly free to believe whatever nonsense you want to
believe. No one will feel compelled to demonstrate TO YOU that you
should believe something else. However, for the benefit of other, more
well-meaning posters, when you post nonsense, there will likely be a
response pointing out the fact that it's nonsense.

PD

My numbers come from a model that still has NOT
been demonstrated to be either inconsistent or
consistent with experiment, you dweeb.

Correction: Your velocity addition formula has *certainly* been
demonstrated to be inconsistent with experiment -- namely, time of
flight measurements of particle interaction products from a collision
with a moving center of mass. The results are entirely consistent with
relativistic formulas.

Your profound ignorance of experimental data is not anyone's problem
but yours.

PD

You can't test a velocity addition formula without
the help of the Doppler formula within the same
theory. Doppler and addition of velocities can't be
tested separately. They form a whole as far as you
need light to fix events.

That is crap. I was referring to *time of flight* experiments, where
the passage of the *actual particle* through detectors, not *light*
from the particles, is recorded. There is no light from the particles
required for this measurement at all.



Your profound ignorance of experimental data is
becoming a serious problem for all of us.

Your *time of flight* is crap. You need some signals to
fix events, ok? They may be light, sound, or any kind
of propagation carrying the information that an event has
ocurred.

Modify the gedanken as follows:
My friend and I each start at point A. At the same instant, we start
traveling at 60% the speed of sound. He in one direction; me in the
exact opposite direction. After a certain amount of time, he emits
a sound back in the direction of our starting point (and me).

Questions:
Can I hear the sound?
If so, what frequency is it?
What is our relative velocity to each other?

Answers:
Your relative speed is v = 60% + 60% = 120%
percent of sound speed. The frequency of the sound your
friend emitted, multiplied by Exp(-1.2) = 0.301. So if he emitted
an ultrasound with frequency 20 KHz, you will hear a signal
with frequency 6.02 KHz (it's within the human hearing).

Notice that you still can construct a 'special theory of relativity'
postulating that no body can travel faster than the speed of sound.
What would the answer be to that gedanken within that 'special
theory of relativity'?

Do you know what is saving Einstein's theories from collapse?
Our current technology can't still deal with FTL propagations.

"- Our future is there, see the light?
- No, I can't still hear it!
- Open your eyes, dumbo, not your ears."
(said a bat to another bat :-)


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