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Re: Variable Time and the Variable Speed of Light

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  Re: Variable Time and the Variable Speed of Light numbernumber1964@gmail.com - 2018-09-06 15:12 -0700
    Re: Variable Time and the Variable Speed of Light Odd Bodkin <bodkinodd@gmail.com> - 2018-09-06 22:43 +0000
      Re: Variable Time and the Variable Speed of Light numbernumber1964@gmail.com - 2018-09-06 16:18 -0700
        Re: Variable Time and the Variable Speed of Light Odd Bodkin <bodkinodd@gmail.com> - 2018-09-07 00:52 +0000
        Re: Variable Time and the Variable Speed of Light Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-09-07 05:08 +0200
          Re: Variable Time and the Variable Speed of Light consequently7990662@gmail.com - 2018-09-06 20:18 -0700
            Re: Variable Time and the Variable Speed of Light Odd Bodkin <bodkinodd@gmail.com> - 2018-09-07 11:34 +0000
      Re: Variable Time and the Variable Speed of Light numbernumber1964@gmail.com - 2018-09-06 16:53 -0700
        Re: Variable Time and the Variable Speed of Light Odd Bodkin <bodkinodd@gmail.com> - 2018-09-07 00:52 +0000
      Re: Variable Time and the Variable Speed of Light moroney@world.std.spaamtrap.com (Michael Moroney) - 2018-09-07 01:25 +0000
        Re: Variable Time and the Variable Speed of Light consequently7990662@gmail.com - 2018-09-06 20:07 -0700
    Re: Variable Time and the Variable Speed of Light Tom Roberts <tjroberts137@sbcglobal.net> - 2018-09-06 18:15 -0500

#470688 — Re: Variable Time and the Variable Speed of Light

It is not physically possible to measure the velocity of light since one cannot produces a single light pulse that can propagates a distance that can be recorded using a circuit since the reaction time of a circuit would be to large to determine the velocity of light.

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#470712

<numbernumber1964@gmail.com> wrote:
> It is not physically possible to measure the velocity of light since one
> cannot produces a single light pulse that can propagates a distance that
> can be recorded using a circuit since the reaction time of a circuit
> would be to large to determine the velocity of light.
> 

In my sophomore year in college, I measured the speed of light by arranging
mirrors at the end of a long hallway in a university building, and firing a
shuttered HeNe laser four passes back and forth, to a photodiode connected
to a small amp and an oscilloscope. 200ft x 4 ~ 0.8 microseconds, which is
a piece of cake on an o’scope. 

It was so easy that I did it with two lab partners, as did five other lab
group trios the same day. 

-- 
Odd Bodkin — Maker of fine toys, tools, tables

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#470734

How can you measure the velocity of light with a laser. Where in the beginning and ending the the pulse?

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#470747

<numbernumber1964@gmail.com> wrote:
> How can you measure the velocity of light with a laser. Where in the
> beginning and ending the the pulse?
> 
> 

You put a camera shutter in front of it, silly. 

-- 
Odd Bodkin — Maker of fine toys, tools, tables

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#470758

numbernumber1964@gmail.com wrote:
> How can you measure the velocity of light with a laser. Where in the beginning and ending the the pulse?

_Speed_, not velocity.  Velocity is a *vector*; speed is its magnitude.

Put a mirror a known distance D away from the laser emitter. Point the laser
at the mirror such that it hits it at an angle of approximately 90°.
Measure the time T that it takes for the laser pulse to leave the emitter
and return from the mirror.  Divide twice the distance by the time obtained
to calculate the two-way speed of light:

  c = 2D/T

It helps if D is large, but not so large that gravity matters (otherwise you
have to consider that, too).  For example, a large interferometer like LIGO
or an earth-based emitter and a mirror on the Moon work well.

Precision can be increased if you let the laser pulse bounce forward and
back a few times:

<https://en.wikipedia.org/wiki/Speed_of_light#Time_of_flight_techniques>

If you have a laser interferometer with movable mirrors, you can also
calculate c from the interference of a laser beam of known frequency f
with itself:

  c = λ f,

where λ is the measured wavelength.

<https://en.wikipedia.org/wiki/Speed_of_light#Interferometry>

-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

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#470763

On Thursday, September 6, 2018 at 8:08:43 PM UTC-7, Thomas 'PointedEars' Lahn wrote:
> numbernumber1964@gmail.com wrote:
> > How can you measure the velocity of light with a laser. Where in the beginning and ending the the pulse?
> 
> _Speed_, not velocity.  Velocity is a *vector*; speed is its magnitude.
> 
> Put a mirror a known distance D away from the laser emitter. Point the laser
> at the mirror such that it hits it at an angle of approximately 90°.
> Measure the time T that it takes for the laser pulse to leave the emitter
> and return from the mirror.  Divide twice the distance by the time obtained
> to calculate the two-way speed of light:
> 
>   c = 2D/T
> 
> It helps if D is large, but not so large that gravity matters (otherwise you
> have to consider that, too).  For example, a large interferometer like LIGO
> or an earth-based emitter and a mirror on the Moon work well.
> 
> Precision can be increased if you let the laser pulse bounce forward and
> back a few times:
> 
> <https://en.wikipedia.org/wiki/Speed_of_light#Time_of_flight_techniques>
> 
> If you have a laser interferometer with movable mirrors, you can also
> calculate c from the interference of a laser beam of known frequency f
> with itself:
> 
>   c = λ f,
> 
> where λ is the measured wavelength.
> 
> <https://en.wikipedia.org/wiki/Speed_of_light#Interferometry>
> 
> -- 
> PointedEars
> 
> Twitter: @PointedEars2
> Please do not cc me. / Bitte keine Kopien per E-Mail.

_________________________________________________________________


This c = λ f,  is a wave equation but the formation of a wave requires a medium (ether) composed of matter yet light produces the interference effect in vacuum that is void of matter which nullifies your measurement of the velocity of light using an interferometer.

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#470809

<consequently7990662@gmail.com> wrote:
> On Thursday, September 6, 2018 at 8:08:43 PM UTC-7, Thomas 'PointedEars' Lahn wrote:
>> numbernumber1964@gmail.com wrote:
>>> How can you measure the velocity of light with a laser. Where in the
>>> beginning and ending the the pulse?
>> 
>> _Speed_, not velocity.  Velocity is a *vector*; speed is its magnitude.
>> 
>> Put a mirror a known distance D away from the laser emitter. Point the laser
>> at the mirror such that it hits it at an angle of approximately 90°.
>> Measure the time T that it takes for the laser pulse to leave the emitter
>> and return from the mirror.  Divide twice the distance by the time obtained
>> to calculate the two-way speed of light:
>> 
>> c = 2D/T
>> 
>> It helps if D is large, but not so large that gravity matters (otherwise you
>> have to consider that, too).  For example, a large interferometer like LIGO
>> or an earth-based emitter and a mirror on the Moon work well.
>> 
>> Precision can be increased if you let the laser pulse bounce forward and
>> back a few times:
>> 
>> <https://en.wikipedia.org/wiki/Speed_of_light#Time_of_flight_techniques>
>> 
>> If you have a laser interferometer with movable mirrors, you can also
>> calculate c from the interference of a laser beam of known frequency f
>> with itself:
>> 
>> c = λ f,
>> 
>> where λ is the measured wavelength.
>> 
>> <https://en.wikipedia.org/wiki/Speed_of_light#Interferometry>
>> 
>> -- 
>> PointedEars
>> 
>> Twitter: @PointedEars2
>> Please do not cc me. / Bitte keine Kopien per E-Mail.
> 
> _________________________________________________________________
> 
> 
> This c = λ f,  is a wave equation but the formation of a wave requires a
> medium (ether) composed of matter 

That is incorrect 

> yet light produces the interference effect in vacuum that is void of
> matter which nullifies your measurement of the velocity of light using an interferometer.
> 
> 
> 
> 
> 
> 



-- 
Odd Bodkin — Maker of fine toys, tools, tables

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#470739

On Thursday, September 6, 2018 at 3:43:26 PM UTC-7, Odd Bodkin wrote:
> <numbernumber1964@gmail.com> wrote:
> > It is not physically possible to measure the velocity of light since one
> > cannot produces a single light pulse that can propagates a distance that
> > can be recorded using a circuit since the reaction time of a circuit
> > would be to large to determine the velocity of light.
> > 
> 
> In my sophomore year in college, I measured the speed of light by arranging
> mirrors at the end of a long hallway in a university building, and firing a
> shuttered HeNe laser four passes back and forth, to a photodiode connected
> to a small amp and an oscilloscope. 200ft x 4 ~ 0.8 microseconds, which is
> a piece of cake on an o’scope. 
> 
> It was so easy that I did it with two lab partners, as did five other lab
> group trios the same day. 
> 
> -- 
> Odd Bodkin — Maker of fine toys, tools, tables


250 meters (800ft) and 1/8000 shutter speed = velocity of light of 2 x 10^6 m/s..........You didn't make this up did you?

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#470748

<numbernumber1964@gmail.com> wrote:
> On Thursday, September 6, 2018 at 3:43:26 PM UTC-7, Odd Bodkin wrote:
>> <numbernumber1964@gmail.com> wrote:
>>> It is not physically possible to measure the velocity of light since one
>>> cannot produces a single light pulse that can propagates a distance that
>>> can be recorded using a circuit since the reaction time of a circuit
>>> would be to large to determine the velocity of light.
>>> 
>> 
>> In my sophomore year in college, I measured the speed of light by arranging
>> mirrors at the end of a long hallway in a university building, and firing a
>> shuttered HeNe laser four passes back and forth, to a photodiode connected
>> to a small amp and an oscilloscope. 200ft x 4 ~ 0.8 microseconds, which is
>> a piece of cake on an o’scope. 
>> 
>> It was so easy that I did it with two lab partners, as did five other lab
>> group trios the same day. 
>> 
>> -- 
>> Odd Bodkin — Maker of fine toys, tools, tables
> 
> 
> 250 meters (800ft) and 1/8000 shutter speed = velocity of light of 2 x 10^6
> m/s..........You didn't make this up did you?
> 

You did that wrong. 

-- 
Odd Bodkin — Maker of fine toys, tools, tables

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#470751

Odd Bodkin <bodkinodd@gmail.com> writes:

><numbernumber1964@gmail.com> wrote:
>> It is not physically possible to measure the velocity of light since one

"Those who say it is not possible, should not interrupt those doing it."

--Chinese proverb


>> cannot produces a single light pulse that can propagates a distance that
>> can be recorded using a circuit since the reaction time of a circuit
>> would be to large to determine the velocity of light.
>> 

>In my sophomore year in college, I measured the speed of light by arranging
>mirrors at the end of a long hallway in a university building, and firing a
>shuttered HeNe laser four passes back and forth, to a photodiode connected
>to a small amp and an oscilloscope. 200ft x 4 ~ 0.8 microseconds, which is
>a piece of cake on an o’scope. 

I did pretty much the exact same experiment in freshman/sophomore college.

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#470757

On Thursday, September 6, 2018 at 6:25:15 PM UTC-7, Michael Moroney wrote:
> Odd Bodkin <bodkinodd@gmail.com> writes:
> 
> ><numbernumber1964@gmail.com> wrote:
> >> It is not physically possible to measure the velocity of light since one
> 
> "Those who say it is not possible, should not interrupt those doing it."
> 
> --Chinese proverb
> 
> 
> >> cannot produces a single light pulse that can propagates a distance that
> >> can be recorded using a circuit since the reaction time of a circuit
> >> would be to large to determine the velocity of light.
> >> 
> 
> >In my sophomore year in college, I measured the speed of light by arranging
> >mirrors at the end of a long hallway in a university building, and firing a
> >shuttered HeNe laser four passes back and forth, to a photodiode connected
> >to a small amp and an oscilloscope. 200ft x 4 ~ 0.8 microseconds, which is
> >a piece of cake on an o’scope. 
> 
> I did pretty much the exact same experiment in freshman/sophomore college

_____________________________________________________

250 meters (800ft) and 1/8000 shutter speed = velocity of light of 2 x 10^6 m/s. Was your roommate mickey mouse?

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#470733

On 9/6/18 5:12 PM, numbernumber1964@gmail.com wrote:
> It is not physically possible to measure the velocity of light since
> one cannot produces a single light pulse that can propagates a
> distance that can be recorded using a circuit since the reaction time
> of a circuit would be to large to determine the velocity of light.

This is just plain and simply not true. Today it is downright easy to 
measure the speed of light that way.

Why do you bother making stuff up and pretending it is true?

Tom Roberts

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