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Re: Calculating G

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On 31/12/2016 12:06 PM, Peter Riedt wrote:
> On Saturday, December 31, 2016 at 8:36:04 AM UTC+8, Sylvia Else
> wrote:
>> On 31/12/2016 9:43 AM, Peter Riedt wrote:
>>> On Friday, December 30, 2016 at 6:43:45 PM UTC+8, Sylvia Else
>>> wrote:
>>>> On 30/12/2016 8:11 PM, Peter Riedt wrote:
>>>>> On Friday, December 30, 2016 at 10:22:43 AM UTC+8, Sylvia
>>>>> Else wrote:
>>>>>> On 29/12/2016 11:21 PM, Peter Riedt wrote:
>>>>>>> On Thursday, December 29, 2016 at 2:21:38 PM UTC+8,
>>>>>>> Sylvia Else wrote:
>>>>>>>> On 29/12/2016 1:13 AM, Peter Riedt wrote:
>>>>>>>>> Calculating G
>>>>>>>>>
>>>>>>>>> The constant G was anticipated by Newton but first
>>>>>>>>> accurately determined in the laboratory by Henry
>>>>>>>>> Cavendish in 1798. It has the value
>>>>>>>>> G=6.674E-11m3kg−1s−2 (cubic meters per kilogram
>>>>>>>>> second squared).
>>>>>>>>>
>>>>>>>>> G can be derived from elements of a star by the
>>>>>>>>> formula G=gstar*rstar^2/Mstar
>>>>>>>>>
>>>>>>>>> gstar	   rstar	   Mstar	    G Sun	 273.97
>>>>>>>>> 696,000,000 1.99E+30 6.674E-11 ACa	 200.18
>>>>>>>>> 853,992,000	 2.19E+30 6.674E-11 ACb	 332.10
>>>>>>>>> 602,040,000	 1.80E+30	6.674E-11 AC c	1695.00
>>>>>>>>> 98,136,000 2.45E+29	6.674E-11
>>>>>>>>>
>>>>>>>>> gstar = surface acceleration in m/sec rstar = radius
>>>>>>>>> in m Mstar = mass in kg
>>>>>>>>
>>>>>>>> How are you going to get the mass and surface
>>>>>>>> acceleration of the star?
>>>>>>>>
>>>>>>>> Sylvia.
>>>>>>>
>>>>>>> I got the mass of the sun and Alpha Centauri A, B, C
>>>>>>> from sources available on the Internet:
>>>>>>
>>>>>> Are you for real? How do you think they ended up on the
>>>>>> Internet?
>>>>>>
>>>>>> Sylvia.
>>>>>
>>>>> What is your point?
>>>>>
>>>>
>>>> The mass of the sun that's on the Internet was calculated by
>>>> applying the measured value of G to the orbits of the planets.
>>>>
>>>> So calculating G using the mass of the sun obtained from the
>>>> Internet is actually calculating G from G.
>>>>
>>>> The other masses are either derived similarly from orbital
>>>> speeds, or are derived from brightness based on stellar
>>>> physics.
>>>>
>>>> Surface accelerations are calculated from the mass and G and
>>>> measured radius.
>>>>
>>>> As always, your attempts to calculate G are completely
>>>> circular.
>>>>
>>>> There is no known way of calculating it, other than from the
>>>> measured attraction between masses that are known accurately
>>>> by means other than orbital mechanics.
>>>>
>>>> Sylvia.
>>>
>>> You did not grasp it. I am not trying to calculate G; I am using
>>> it to establish relationships between elements of free fall
>>> objects and secondly if it has the same value in other star
>>> systems. You have too narrow a view.
>>>
>>
>> Orbital mechanics is already well understood. There's nothing for
>> you to establish.
>>
>> As for determining whether it has the same value in other star
>> systems, this would involve finding gravitationally bound stellar
>> objects, and determining their mass otherwise than by using orbital
>> mechanics. Estimates based on brightness and stellar physics are
>> much too inaccurate to be useful unless the constant G is hugely
>> variable.  If it were, that would have been noticed already.
>>
>> Sylvia.
>
> I agree and submit that the mass of the three Alpha Centauri stars
> and their surface acceleration as stated in the literature are
> grossly inaccurate. Furthermore the value of G is defined only for
> the solar system and no evidence exists it is the same in other star
> systems.
>


We know that it is the same to a high degree of accuracy all the way out 
to the current position of Voyager 1 (137AU). It's value beyond that is 
constrained by the requirement that the orbital periods of binary stars 
be consistent with their separation and their masses, as estimated using 
the brightness (or period, in the case of some variable stars) using 
stellar physics.

So while there's no direct evidence that the value is exactly the same 
beyond the solar system, there is evidence that its value is not hugely 
different. Given its constancy out to Voyager 1, there is no present 
reason to think it varies.

Either way, your circular analyses contribute nothing to our knowledge.

Sylvia.

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Thread

Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2016-12-28 06:13 -0800
  Re: Calculating G Poutnik <poutnik4nntp@gmail.com> - 2016-12-28 15:40 +0100
    Re: Calculating G Poutnik <poutnik4nntp@gmail.com> - 2016-12-28 15:41 +0100
    Re: Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2016-12-28 22:10 -0800
      Re: Calculating G "hanson" <hanson@quick.net> - 2016-12-28 22:29 -0800
      Re: Calculating G Poutnik <poutnik4nntp@gmail.com> - 2016-12-29 08:07 +0100
        Re: Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2016-12-29 16:53 -0800
  Re: Calculating G Alan Folmsbee <omnilobe@gmail.com> - 2016-12-28 09:27 -0800
  Re: Calculating G Sylvia Else <sylvia@not.at.this.address> - 2016-12-29 17:21 +1100
    Re: Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2016-12-29 04:21 -0800
      Re: Calculating G Wally W. <ww84wa@aim.com> - 2016-12-29 09:11 -0500
        Re: Calculating G "hanson" <hanson@quick.net> - 2016-12-29 06:34 -0800
          Re: Calculating G noTthaTguY <abu.kuanysh05@gmail.com> - 2016-12-29 15:40 -0800
          Re: Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2016-12-29 16:52 -0800
        Re: Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2016-12-29 16:59 -0800
          Re: Calculating G Odd Bodkin <bodkinodd@gmail.com> - 2017-01-03 12:19 -0600
            Re: Calculating G noTthaTguY <abu.kuanysh05@gmail.com> - 2017-01-03 12:43 -0800
      Re: Calculating G Sylvia Else <sylvia@not.at.this.address> - 2016-12-30 13:22 +1100
        Re: Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2016-12-30 01:11 -0800
          Re: Calculating G Sylvia Else <sylvia@not.at.this.address> - 2016-12-30 21:43 +1100
            Re: Calculating G "hanson" <hanson@quick.net> - 2016-12-30 06:48 -0800
            Re: Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2016-12-30 14:43 -0800
              Re: Calculating G Sylvia Else <sylvia@not.at.this.address> - 2016-12-31 11:35 +1100
                Re: Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2016-12-30 17:06 -0800
                Re: Calculating G Sylvia Else <sylvia@not.at.this.address> - 2016-12-31 12:40 +1100
                Re: Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2016-12-30 23:22 -0800
                Re: Calculating G Sylvia Else <sylvia@not.at.this.address> - 2016-12-31 20:28 +1100
                Re: Calculating G "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-12-31 11:07 -0800
                Re: Calculating G "hanson" <hanson@quick.net> - 2016-12-31 11:16 -0800
                Re: Calculating G "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-12-31 13:22 -0800
                Re: Calculating G "hanson" <hanson@quick.net> - 2016-12-31 15:36 -0800
                Re: Calculating G Sylvia Else <sylvia@not.at.this.address> - 2017-01-01 11:49 +1100
              Re: Calculating G Odd Bodkin <bodkinodd@gmail.com> - 2017-01-03 15:09 -0600
                Re: Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2017-01-03 16:22 -0800
                Re: Calculating G noTthaTguY <abu.kuanysh05@gmail.com> - 2017-01-03 16:57 -0800
                Re: Calculating G Odd Bodkin <bodkinodd@gmail.com> - 2017-01-04 10:22 -0600
                Re: Calculating G Peter Riedt <riedt1@yahoo.co.uk> - 2017-01-05 16:02 -0800
                Re: Calculating G Odd Bodkin <bodkinodd@gmail.com> - 2017-01-06 07:09 -0600

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