There are two inertial reference frames F0 and F1 moving along the x-axis with F1 moving in the positive direction relative to F0 with a velocity V=c*sqrt(3)/2.
In F1, a laser is pointed along the x-axis in the positive x direction. If that laser in F1 is turned on as measured in F1 for 20 seconds, what do observers in F0 say the length of the beam is that was emitted?
Do observers in F0 say it is simply 40 - 40 * sqrt(3)/2 light-seconds?
Thanks,
David Seppala
Bastrop TX

On Monday, May 30, 2022 at 11:53:16 AM UTC-7, sep...@yahoo.com wrote:
> There are two inertial reference frames F0 and F1 moving along the x-axis with F1 moving in the positive direction relative to F0 with a velocity V=c*sqrt(3)/2.
> In F1, a laser is pointed along the x-axis in the positive x direction. If that laser in F1 is turned on as measured in F1 for 20 seconds, what do observers in F0 say the length of the beam is that was emitted?
> Do observers in F0 say it is simply 40 - 40 * sqrt(3)/2 light-seconds?
> Thanks,
> David Seppala
> Bastrop TX

Length contraction is bogus. The hypersphere-universe expands instead.

Mitchell Raemsch

On Monday, May 30, 2022 at 11:53:16 AM UTC-7, sep...@yahoo.com wrote:
> Do observers in F0 say it is simply 40 - 40 * sqrt(3)/2 light-seconds?

No. Enroll into an intro class. Stop trolling. Makes you look even stupider than you are.

On Monday, May 30, 2022 at 11:53:16 AM UTC-7, sep...@yahoo.com wrote:
> There are two inertial reference frames F0 and F1 moving along the x-axis with F1
> moving in the positive direction relative to F0 with a velocity V=c*sqrt(3)/2.

More correctly, there are two inertial coordinate systems S0 and S1...

> In F1, a laser is pointed along the x-axis in the positive x direction. If that laser in
> F1 is turned on as measured in F1 for 20 seconds, what do observers in F0 say the
> length of the beam is that was emitted?

It's wrong to phrase the question in terms of what someone says, first because relativity is not a subjectivist theory, and second because people can say wrong things, etc. What you really mean is "If someone was accurately stating the facts, what would they say?" But this shows that the people saying things is superfluous, and what you really mean to ask is "What is the spatial length of the beam in terms of S0?" Whether or not a particular person (or parrot, or rock) speaks the answer to this question is irrelevant..

> Do observers in F0 say it is simply 40 - 40 * sqrt(3)/2 light-seconds?

Translation: Is the spatial length of the beam equal to 40 - 40 * sqrt(3)/2 light-seconds in terms of S0? The answer, of course, is yes, although it would typically be written in terms of the Doppler wavelength factor as 20sqrt[(1-v)/(1+v)]. But this is trivial. The most important thing for you to learn today is what was typed up above. Everyone agrees with this fact, i.e., that this is the spatial length of the beam in terms of S0. It doesn't matter if you are at rest in S0 or not, you still agree with this objective fact.
Just state the facts... stop thinking in terms of "what so-and-so says". That is a big part of what is misleading you.

On Monday, May 30, 2022 at 12:40:49 PM UTC-7, Al Coe wrote:
> On Monday, May 30, 2022 at 11:53:16 AM UTC-7, sep...@yahoo.com wrote:
> > There are two inertial reference frames F0 and F1 moving along the x-axis with F1
> > moving in the positive direction relative to F0 with a velocity V=c*sqrt(3)/2.
> More correctly, there are two inertial coordinate systems S0 and S1...
> > In F1, a laser is pointed along the x-axis in the positive x direction. If that laser in
> > F1 is turned on as measured in F1 for 20 seconds, what do observers in F0 say the
> > length of the beam is that was emitted?
> It's wrong to phrase the question in terms of what someone says, first because relativity is not a subjectivist theory, and second because people can say wrong things, etc. What you really mean is "If someone was accurately stating the facts, what would they say?" But this shows that the people saying things is superfluous, and what you really mean to ask is "What is the spatial length of the beam in terms of S0?" Whether or not a particular person (or parrot, or rock) speaks the answer to this question is irrelevant.
> > Do observers in F0 say it is simply 40 - 40 * sqrt(3)/2 light-seconds?
> Translation: Is the spatial length of the beam equal to 40 - 40 * sqrt(3)/2 light-seconds in terms of S0? The answer, of course, is yes, although it would typically be written in terms of the Doppler wavelength factor as 20sqrt[(1-v)/(1+v)]. But this is trivial. The most important thing for you to learn today is what was typed up above. Everyone agrees with this fact, i.e., that this is the spatial length of the beam in terms of S0. It doesn't matter if you are at rest in S0 or not, you still agree with this objective fact.
> Just state the facts... stop thinking in terms of "what so-and-so says". That is a big part of what is misleading you.

Both frames would contract. But that has never been measured.
The universe expands instead.

Mitchell Raemsch

On 5/30/22 2:40 PM, Al Coe wrote:
> [to sepp623@yahoo.com]
> [... lots of correct statements]
> Just state the facts... stop thinking in terms of "what so-and-so says".
> That is a big part of what is misleading you.

Well said. It applies to many people around here.

Tom Roberts