Uncertainty of gravitational constant
Aleksandr Timofeev
bi...@warthog.as.utexas.edu (Bill Jefferys) wrote:
[snip]
> Traditionally, the gravitational constant as used in celestial mechanics
> has been a _defined constant_, not a measured quantity. ...
Your account of a problem is characterized by sharp clearness.
The following problems could you make clear:
1. What role play the empirical corrections inside the theories of a
celestial mechanics from a physical point of view?
2. What influence render the empirical corrections on values of computed
parameters in a celestial mechanics?
3. What " power weight " of the empirical corrections now and earlier?
4. What influence have rendered the measured values of planetary masses on
the empirical corrections?
Regards,
Aleksandr
--
Aleksandr Timofeev | Email: t...@alpha.dnttm.rssi.ru
Homepage: http://solar.cini.utk.edu/~russeds/unknown/astrochem/
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Aleksandr Timofeev
Esa A E Peuha <pe...@vesuri.helsinki.fi> wrote:
> Aleksandr Timofeev <t...@alpha.dnttm.rssi.ru> writes:
>
> > There are two gravitational constants:
> > 1 - Gravitational constant measured in laboratories on the Earth;
> > 2 - Gravitational constant calculated by methods of a celestial
> > mechanics from the theories for Solar system.
> > These gravitational constants should have identical values,
> > but they differ from each other.
>
> That depends on what you mean by "differing". The obvious difference is
> that constant 1 has kilogram as its unit of mass, while constant 2 has the
> mass of Sun. However, the *only* currently available way to get the mass
> of Sun in kilograms is to equate these two constants, so they simply can't
> have different values.
>
1.
------------------------------------------------------------------
Re: Uncertainty of gravitational constant
Author: Jim Carr
Email: j...@ibms48.scri.fsu.edu
Date: 1998/11/03
Forums: sci.physics
Aleksandr Timofeev <t...@alpha.dnttm.rssi.ru> writes:
joe...@iglou.com (Joe Fischer) wrote:
>> Maybe the question can be treated better in
>> sci.astro and it would help if you stated how you
>> arrived at two different values for G.
>
>Compare the data parameters in manuals for 1980 and now.
Since there are at present two measurements of G that disagree
by more than their associated uncertainties, even the terrestrial
values are suspect.
--
James A. Carr <j...@scri.fsu.edu> | Commercial e-mail is _NOT_
http://www.scri.fsu.edu/~jac/ | desired to this or any address
Supercomputer Computations Res. Inst. | that resolves to my account
Florida State, Tallahassee FL 32306 | for any reason at any time.
------------------------------------------------------------------
------------------------------------------------------------------
2. Here i explain, how i arrived at two different values for G.
The theory DE200/LE200 takes into account: nine planets, moon five
largest
asteroids, form of the Earth, singularity of rotary motion of the Earth
and
moon, effects of the theory of gravitation Einstein. The theory
DE200/LE200
envelops period since a 1800 till a 2050.
----------------------------------------------------------------------
The values planetary masses and initial elements of orbits are selected
so,
that the divergences with all known observations do not exceed 0.05 ".
----------------------------------------------------------------------
What it means from a physical point of view?
The time-space-averaging operation for the whole Solar system is
produced.
The time is taken into account - during several hundreds years.
Space is taken into account - space enveloping all Solar system.
Yes, the values of planetary masses and gravitational constant are
computed parameters in a celestial mechanics, but they are founded on
a vast observant material. They enter in all expressions of the theory
of
a celestial mechanics as a product MG, they cannot be separated from
each
other.
The theory DE200/LE200 is the basis almost of all Astronomical almanacs
from 1980.
One circumstance calls surprise - why values of planetary masses for
theory DE200/LE200 differ from planetary masses measured by space
vehicles?
Compare the values of planetary masses selected by DE200/LE200(in
manuals
for 1980)and now - http://ssd.jpl.nasa.gov/astro_constants.html , we
observe systematic increase values of planetary masses.
This systematic increase values is explained by large confidence to
measurements executed space vehicles. The methodology of measurements by
space vehicles is based on G. G measured on the Earth!!!
For the matching the values of planetary masses selected by
DE200/LE200
and accepted now, we should accept value G for a Solar system of smaller
than value G measured on the Earth.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Or you should find other explanation to systematic increase values
of all planetary masses.
3. From a physical point of view ...
In case space vehicles, these measurements are executed in immediate
proximity from investigated object (in limited space on a comparison
with
space of a Solar system).
From a physical point of view the theory DE200/LE200 means:
The time-space-averaging operation for the whole Solar system is
produced.
The time is taken into account - during several hundreds years.
Space is taken into account - space enveloping all Solar system.
The theory DE200/LE200 are founded on a vast observant material.
4. What measurements give more reliable the values of planetary masses:
celestial mechanics?
space vehicles?
Esa A E Peuha
> One circumstance calls surprise - why values of planetary masses for
> theory DE200/LE200 differ from planetary masses measured by space
> vehicles?
Do you mean that the value of MG calculated from the orbits of spacecrafts
is different from the value calculated from DE200/LE200? If so, that
difference is remarkable, but it has nothing to do with measuring the value
of G.
Or do you mean that laboratory experiments on Earth give values for G
different from values given by experiments conducted in space vessels?
In that case, the conclusion must be that experiments on Earth are so
inaccurate that they don't give reliable results.
--
Esa Peuha
student of mathematics at the University of Helsinki
http://www.helsinki.fi/~peuha/
Aleksandr Timofeev
Esa A E Peuha <pe...@vesuri.helsinki.fi> wrote:
> Aleksandr Timofeev <t...@alpha.dnttm.rssi.ru> writes:
>
> > One circumstance calls surprise - why values of planetary masses for
> > theory DE200/LE200 differ from planetary masses measured by space
> > vehicles?
>
> is different from the value calculated from DE200/LE200? If so, that
> difference is remarkable, but it has nothing to do with measuring the value
> of G.
increase in relation to appropriate values MG calculated from theory
DE200/LE200.
Compare the values of planetary masses selected by DE200/LE200(in manuals
For the matching the values of planetary masses (m) selected by DE200/LE200
and accepted now (M), we should accept value G for a Solar system of
bigger(?) than value g measured on the Earth:
m(DE200/LE200)*G(Solar system) = M(spacecrafts)*g(Earth)
m(DE200/LE200) < M(spacecrafts)
G(calculated from Solar system) > g(measured on the Earth)
Actually m*g < M*g
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Or you should find other explanation to systematic increase values
of planetary masses measured by spacecrafts.
Regards,
Aleksandr
--
Aleksandr Timofeev | Email: t...@alpha.dnttm.rssi.ru
Homepage: http://solar.cini.utk.edu/~russeds/unknown/astrochem/
-----------== Posted via Deja News, The Discussion Network ==----------
Ray Tomes
> That problem can be summarized by noting that measurements claiming
> four sig.fig. accuracy disagree in the third sig.fig.
Yes, something strange is going on. The following is from a CIFA
newsletter from ~1995 I think.
HELIOGEOPHYSICAL DISTURBANCES INFLUENCE UPON THE RESULTS OF THE
MEASUREMENTS OF GRAVITATION CONSTANT
by B.M.Vladimirsky and A.V.Bruns
Crimean Astrophysical Observatory
334413, p/o Nauchny, Crimea, Ukraine
The value of gravitational constant as measured by classic
instrument - torsion pendulum,- is not defined more precisely over a
long time. It's known that inexplicable variations of these results
are observed at the same apparatus [1]. So it's possible that partial
non-reproducibility of the measurements are caused by unidentified
external agent. Probably this enigmatic factor correlates with
variations of solar activity: the measurements making in years of
high level of solar activity as a rule are smaller as comparison
with those during solar activity minima (23 independent measurements,
1798 - 1981).
Several runs of the measurements of mentioned constant obtained by
O.Karagioz et al [2] using the installation [3] were analyzed in
details. Real presence of external active factor have been confirmed.
In particular it was revealed that abnormal large values of the
constant (G > 6.6800) were observed in days when magnetic activity
index Ap was minimal (Figure, Superposed Epoch Method, P(U*)=3 10 -3 )
This result has high significance level because the same effect is
observed also for another independent run of the measurements and
other magnetic index (Dst). Opposite effect - abnormal low values,
G < 6.6700, takes place for days of strong ionospheric disturbances
connected with large solar chromospheric flares. In this case we have
probably the same situation as was observed by G.Piccardi in his
chemical F-tests [4]. Electromagnetic disturbances caused by X-ray
radiation of the flare in ionospheric conductivity ("sudden
enhancement of atmospherics") influence upon precipitation rate of
Bismuth oxychloride.
The mechanism of the influence of heliogeophysical variations upon
the parameters of torsion pendulum movement is not clear up to now.
Probably the phenomenon can be related with the effect of
"magnitoplastisity" of the thread of pendulum suspension. Relation
of such kind between weak alternate magnetic fields and the
parameters of polycristallic solids is investigated intensively in
last years as dislocations motion. It have been revealed at
initialstage of these studies that the influence of the fields upon
elastic parameters of the solids depends on field frequency [5]. But
the spectrum of background electromagnetic fields changes essentially
during heliogeophysical variations. E.g. during magnetocalm
conditions (Ap < 10) geomagnetic micropulsations Pc4-type (frequency
about 0.01 Hz) are excited over large space regions. In other side,
solar chromospheric flare is accompanied by intensification of
electromagnetic oscillations in broad frequency range at day-side
hemisphere. So these very low frequency field variations can change
probably elastic coefficient of twisting of pendulum thread.
Detailed version of the paper is to be published in Astronomical
Journal (Moscow) in 1995. See also [6].
References
1. Pontikis M.C.//Compt.R.Acad.Csi., 1972, ser.13, V.274, p.437-439.
2. Karagioz O.V., Izmailov V.P., Parhomov A.G. Investigation of the
fluctuations in the results of the measurements of gravitation
constant at the installation with torsion pendulum. Preprint, Moscow,
VENT, 1992, #21 (in Russian).
3. Karagioz O.V., Izmailov V.P., Silin A.A., Duhovskoi E.A. //
Gravitation and Theory of Space-Time, Frendship people Univ., Moscow,
1987, p.102.
4. Piccardi G. The Chemical Basis of Medical Climatology, Ch.Thomas,
Springfield (USA), 1962, p.86.
5. Hayashi S., Takahashi S., Yamamoto M. // Jour.Phys.Soc.Japan,
1971, V.30, p.381.
6. Vladimirsky B.M. // Biophysics, 1992, V.37, iss.3, p.410-417.
-- Ray Tomes -- http://www.kcbbs.gen.nz/users/rtomes/rt-home.htm --
Cycles email list -- http://www.kcbbs.gen.nz/users/af/cyc.htm
Alexandria eGroup list -- http://www.kcbbs.gen.nz/users/af/alex.htm
Boundaries of Science http://www.kcbbs.gen.nz/users/af/scienceb.htm
Aleksandr Timofeev
rto...@kcbbs.gen.nz (Ray Tomes) wrote:
> j...@ibms48.scri.fsu.edu (Jim Carr) wrote:
> > That problem can be summarized by noting that measurements claiming
> > four sig.fig. accuracy disagree in the third sig.fig.
>
> Yes, something strange is going on. The following is from a CIFA
> newsletter from ~1995 I think.
>
> HELIOGEOPHYSICAL DISTURBANCES INFLUENCE UPON THE RESULTS OF THE
> MEASUREMENTS OF GRAVITATION CONSTANT
>
> by B.M.Vladimirsky and A.V.Bruns
> Crimean Astrophysical Observatory
> 334413, p/o Nauchny, Crimea, Ukraine
>
> The value of gravitational constant as measured by classic
> instrument - torsion pendulum,- is not defined more precisely over a
> long time. It's known that inexplicable variations of these results
> are observed at the same apparatus [1]. So it's possible that partial
> non-reproducibility of the measurements are caused by unidentified
> external agent. Probably this enigmatic factor correlates with ...
. ^^^^^^^^^^^^^^^
[snip]
Without any exception all theories of celestial mechanics
contain empirical assumptions with a purpose to match the past and
future observation data. Empirical corrections (depending exclusively
on the intuition of those who elaborate such theories) is an
inevitable evil connected with the imperfection of the mechanical
model of the system under consideration and an influence of
unaccounted and unknown phenomena which affects the system. ..."
. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
See my homepage chapter: 3.The reliability of the input data
3.1 Inner precision of celestial mechanics
Aleksandr Timofeev
--
homepage http://solar.cini.utk.edu/~russeds/unknown/astrochem/
Boundaries of Science http://www.kcbbs.gen.nz/users/af/scienceb.htm
-----------== Posted via Deja News, The Discussion Network ==----------
Esa A E Peuha
> Yes, the values MG calculated from orbits of spacecrafts have systematic
> increase in relation to appropriate values MG calculated from theory
> DE200/LE200.
> Compare the values of planetary masses selected by DE200/LE200(in manuals
> till 1980)and now - see http://ssd.jpl.nasa.gov/astro_constants.html
Are those values on NASA's web page really computed from orbits of
spacecrafts? Anyway, they originate from IAU, so those older values
are probably obsolete.
> For the matching the values of planetary masses (m) selected by DE200/LE200
> and accepted now (M), we should accept value G for a Solar system of
> bigger(?) than value g measured on the Earth:
No, we shouldn't, because that would cause more severe problems than we are
trying to solve. For example, the constancy of G is one of the assumptions
on which the general theory of relativity is based.
Aleksandr Timofeev
Esa A E Peuha <pe...@vesuri.helsinki.fi> wrote:
> Aleksandr Timofeev <t...@alpha.dnttm.rssi.ru> writes:
>
> > increase in relation to appropriate values MG calculated from theory
> > DE200/LE200.
>
> Are those values on NASA's web page really computed from orbits of
> spacecrafts? Anyway, they originate from IAU, so those older values
> are probably obsolete.
>
------------------------------------------------------------------
Re; Uncertainty of gravitational constant
Email: jco...@bnr.ca
Date: 1998/11/20
Forums: sci.astro
As pointed out by this discussion, the methodology of determination of
the masses of solar system objects is significantly different between
the two eras.
Prior to the space age all that could be determined was the angular
position of solar system objects. It was impossible to directly measure
distance. Assuming the applicability of Newton's laws it was possible
to calculate the absolute space position of various objects in terms of
astronomical units, that is setting the distance between the Earth-Moon
center of gravity and the center of gravity of the solar system to 1.0.
Once you have done this you can calculate, highly accurately, a
constant, traditionally called the Gaussian gravitational constant k,
which represents the gravitational
influence of the Sun on the objects in the solar system. Further, by
solving the system so as to minimize deviations between prediction and
future positions it is possible for each of the major planets to
calculate the ratio between their values of k and the value of k for the
Sun. It is NOT possible to calculate the "mass" of any of the objects
in this system. As an additional aid in reducing the massively parallel
calculations, observations of the motion of planetary satellites, in
angular terms, can provide independent measurements of the value of k
for those planets which have moons. That excludes Mercury, Venus,
Pluto, and even to some extent the Earth. That is because we cannot
trivially calculate the distance between the Earth and the Moon in
astronomical units because the Moon is the one object that we cannot
observe from different spots on the Earth's orbit.
I repeat: Using only angular measurements it is impossible to measure
the "mass" of any object. However you can measure the relative mass of
any two objects.
With spaceprobes it is possible to accurately measure their DISTANCE at
any instant in terms of the time it takes light to cross from them to
the observer. You could also measure their angular positions, for
example using a long baseline radio interferometer, but the accuracy of
the distance measurement, in terms of light time, is orders of magnitude
more accurate. Since the length of the SI metre is defined in terms of
the time it takes for light to cross it, or alternatively the speed of
light is now a defining constant of the SI system, we can accurately, to
a matter of centimetres in fact, determine the exact distance to any
spaceprobe in metric units. This permits us, for each object which a
probe passes relatively close to, to determine with significant
accuracy the value representing the strength of the gravitational field
of the object in terms of metric units.
But, once again, you cannot measure the "mass" of any of the objects.
Just as with the older methods, all you can measure is the strength of
the gravitational field. In gravitational theory the strength of the
gravitational field is proportional to the mass and the constant of
proportionality is labelled G. While the value of the field strength is
frequently known to 7 or 8 digits, the value of the constant of
proportionality (in metric units) is only known to about 4 digits.
Note that it is possible to close the loop to some extent. Since we
have now measured the length of the AU in metric units to about 9
digits, and since we know the strengths of the gravitational fields of
many of the solar system objects to 7 or 8 digits, it is possible to
plug this knowledge back into the traditional model. When we do so we
find that there is no significant change except for the orbits of Uranus
and Neptune. In the old model the predictions for these planets drifted
unless a fudge factor was introduced (called planet X). However once
the space probe determined gravitational field strengths are introduced,
that fudge factor disappears and the observed orbits of Uranus and
Neptune are accounted for over the last 200 years.
However any time you see a mass for any object published in terms of
kilograms (or Petatonnes as one source quotes) then you know that the
author is fudging his results to satisfy a semi-literate audience.
--
Jim Cobban | jco...@nortel.ca | Phone: (613) 763-8013
Nortel Networks (MED) | FAX: (613) 763-5199
------------------------------------------------------------------------
[snip]