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Kepler's 3rd with adjusted periods and radii



 
 
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  #11  
Old February 17th 16, 09:32 AM posted to sci.astro
Mike Dworetsky
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Posts: 715
Default Kepler's 3rd with adjusted periods and radii

Peter Riedt wrote:
On Wednesday, February 17, 2016 at 1:17:00 AM UTC+8, Poutnik wrote:
Dne úterý 16. února 2016 14:22:00 UTC+1 Peter Riedt napsal(a):
On Tuesday, February 16, 2016 at 4:03:53 PM UTC+8, Mike Dworetsky
wrote:
Peter Riedt wrote:
Kepler's 3rd with adjusted periods and radii

Kepler's third law in the form t2/r3 gives a constant for solar
objects such as planets and asteroids. It is a precise law but
applying it with the measured values for the orbital periods in
seconds for t and the measured semi major axis in metres for r
produces results with small differences.

Kepler's third law, in a more general form, involves the SUM of
the masses of the two bodies:

(M1+M2)P^2 = a^3 (using units of solar masses, years, and AUs)

Hence for more massive planets like Jupiter you have to take this
into account (Jupiter's mass is around 1/1000 of the Sun's mass).
Just fiddling with numbers is not correct, and inadequate!


I have used your formula (M1+M2)P^2 = a^3 and got the following
results. Can you explain where I used the wrong data or arithmetic?


- Missing gravitational constant and 4.pi^2 factor.
G.(M1+M2). P^2 = 4.pi^2 . a^3

- Missing either conversion to meters and seconds,
either conversion of the gravitational constant for AUs and years.

- Persistent ignoring of rules of processing inaccurate data.


The formula was posted by Mike. Read his post in this thread.


Yes, I stated that the formulae I gave used units of solar mass, years, and
AU. That is not what you are using.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

  #12  
Old February 17th 16, 12:09 PM posted to sci.astro
Poutnik[_5_]
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Posts: 68
Default Kepler's 3rd with adjusted periods and radii

Dne úterý 16. února 2016 21:29:33 UTC+1 Martin Brown napsal(a):
On 16/02/2016 13:21, Peter Riedt wrote:

(M1+M2)P^2 = a^3 (using units of solar masses, years, and AUs)


*UNITS!!!* ^^^^^^^^^^^^


There is hidden implicit G,
with the value approximately 1, and dimension of AU^3 / year^2 / Ms

 




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