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Re: Particle Physics

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On 4/22/2016 12:49 PM, Thomas Heger wrote:
> Am 22.04.2016 14:14, schrieb Odd Bodkin:
>
>>> But after all, you must not leave out the units for speed as well, since
>>> you can only adjust the numbers, but cannot leave out the associated
>>> dimensions (length/time interval).
>>>
>>> Since '1' is a simple number, it has no dimension. But c HAS dimensions,
>>> which are left out for no obvious reasons.
>>
>> What you have encountered is something you can look up: "natural units".
>>
>> It's really not very complicated. In reality, all it is, is the
>> recognition that the units of meters and seconds are historical
>> accidents. Meters arose from some arbitrary division of the
>> circumference of the Earth by the French, and seconds arose from some
>> arbitrary division of the length of the day by the Babylonians. There is
>> no special significance to them. So the question is whether there is a
>> more "natural" system of units where length and time can be measured
>> with the same unit (and this is indeed very possible), and then of
>> course in this system of units, *the value of c is 1 and dimensionless*.
>>
>
> I regard this behaviour as disgusting!
>
> I cannot real see how physicists justify to sweep the dimensions of a
> unit under the rug.

Dimensions and units are two separate things.

Suppose you lived in a town where north-south distances were measured in 
miles and east-west distances were measured in kilometers. Would you say 
that the dimensions of the east-west distances were different than the 
dimensions of the north-south distances? No, of course not. In fact, 
you'd say it's rather ungainly and a bit foolish to have two different 
units to try to come up with an interval between any two places. There'd 
be all those conversion factors and what-not. Why not just go with miles 
and be done with it? Or kilometers and be done with it?

>
> You may call the *numbers* random human choice. But 1 lightsecond per
> second as value of c is certainly possible.

Not a lightsecond. Just a second. A second of distance. To get from a 
meter of distance to a second of distance, all you need is a conversion 
factor. Just like you'd convert miles to kilometers.

The conversion factor is 1 second = 300,000,000 m.

So now if you're measuring speeds, that has units seconds per second.

By the way, this conversion factor is commonly written as (300,000,000 
m/s). Look familiar? That's right, c is just a conversion factor.

Of course, once you move to sensible units in town, you don't need the 
conversion factor for kilometers/mile. Likewise if you stick with the 
same units (seconds) for distance and time, then you won't need that 
pesky conversion factor of c, either. The conversion factor is just 1.

>
> BUT now you have a circular definition of the dimensions of the type
> length, since c is contained twice in the statement above:
>
> - once in the term light-second
> - which is used to make a statement about the value of c
>
> Now the question: how long is a lightsecond ?
>
> It's roughly 300.000.000 meters.
>
> So: how long is a meter?
>
> It's roughly 1/300.000.000 of a light second.
>
>
> TH


-- 
Odd Bodkin --- maker of fine toys, tools, tables

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Particle Physics Carl Susumu <numbernumber1212@gmail.com> - 2016-04-21 17:09 -0700
  Re: Particle Physics Gary Harnagel <hitlong@yahoo.com> - 2016-04-21 19:42 -0700
    Re: Particle Physics Thomas Heger <ttt_heg@web.de> - 2016-04-22 06:42 +0200
      Re: Particle Physics Odd Bodkin <bodkinodd@gmail.com> - 2016-04-22 07:14 -0500
        Re: Particle Physics David Fuller <fuller.david@hotmail.com> - 2016-04-22 07:01 -0700
        Re: Particle Physics Thomas Heger <ttt_heg@web.de> - 2016-04-22 19:49 +0200
          Re: Particle Physics Odd Bodkin <bodkinodd@gmail.com> - 2016-04-22 13:06 -0500
            Re: Particle Physics Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2016-04-23 01:37 +0200
          Re: Particle Physics Tom Roberts <tjroberts137@sbcglobal.net> - 2016-04-22 13:35 -0500
            Re: Particle Physics Thomas Heger <ttt_heg@web.de> - 2016-04-22 22:29 +0200
              Re: Particle Physics Dirk Van de moortel <dirkvandemoortel@hotspam.not> - 2016-04-22 23:32 +0200
                Re: Particle Physics Thomas Heger <ttt_heg@web.de> - 2016-04-23 06:15 +0200
                Re: Particle Physics JanPB <filmart@gmail.com> - 2016-04-22 22:25 -0700
                Re: Particle Physics Thomas Heger <ttt_heg@web.de> - 2016-04-23 23:18 +0200
                Re: Particle Physics Odd Bodkin <bodkinodd@gmail.com> - 2016-04-24 13:55 -0500
              Re: Particle Physics Odd Bodkin <bodkinodd@gmail.com> - 2016-04-23 08:33 -0500
                Re: Particle Physics Dirk Van de moortel <dirkvandemoortel@hotspam.not> - 2016-04-23 15:53 +0200
                Re: Particle Physics Thomas Heger <ttt_heg@web.de> - 2016-04-23 20:36 +0200
                Re: Particle Physics Odd Bodkin <bodkinodd@gmail.com> - 2016-04-24 13:59 -0500
              Re: Particle Physics Tom Roberts <tjroberts137@sbcglobal.net> - 2016-04-23 16:43 -0500
                Re: Particle Physics Thomas Heger <ttt_heg@web.de> - 2016-04-24 07:16 +0200
                Re: Particle Physics Odd Bodkin <bodkinodd@gmail.com> - 2016-04-24 14:02 -0500
                Re: Particle Physics Thomas Heger <ttt_heg@web.de> - 2016-04-25 06:55 +0200
                Re: Particle Physics Odd Bodkin <bodkinodd@gmail.com> - 2016-04-25 06:07 -0500
                Re: Particle Physics Thomas Heger <ttt_heg@web.de> - 2016-04-26 22:24 +0200

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