Neptune anomaly

Stupendous_Man ha scritto:

Jonathan Thornburg -- remove -animal to reply wrote:

I don't recall the reference, but I recall reading a paper in the
Astronomical Journal dated sometime in the 1980s, which concluded
that after due consideration of the error bars in the observations,
there were no unresolved deviations. That is, the authors found that
the modern (very accurately known) orbits of the outer planets did
indeed fit all the observations (including the older ones) to within
reasonable estimates of the observational accuracy.

Perhaps you were remembering this paper:

http://adsabs.harvard.edu/cgi-bin/np...510b 0d825109

Thanks for the precious reference ([1]).

In [1] Standish demostrates the "lack of problems with Neptune's
orbit" by re-examining the available data . On pp. 2001-2006 he argues
that:

1) Galileo did not mean what he wrote. His observations should be
interpreted so as to fit what we expect.

2) Lalande's data are uncertain. If one fits the uncertainty to our
reasonable expectations then the problem disappears.

3) It is not true that Neptune does not behave as predicted.
Long-terms predictions about it are affected by uncontrollable
indeterminacies in the observational data. They are however
conceptually within our current understanding ("Any residual
systematic trends in the residuals of Uranus and Neptune are certainly
explainable by these uncertainties in the observational data").
Uncertainties provide a certain explanation.

It is a plausible debunking argument, but , as pointed out by others in
this thread, it is not predictive (and hence not falsifiable). If some
day a theory (my original question was motivated by my interest in
MOND) will describe correctly, say, the Pioneer anomaly, get rid of
dark matter AND fit the "unplausible" data that Myles Standish
discards, then this Neptune issue may be worth a second look.

Interestingly in [2] Standish writes that "while the ephemerides of
Uranus and Neptune seem to have no unexplained problems, the ephemeris
of Pluto does have problems ... there is a large bias which cannot be
removed from the residuals by a mere orbit adjustment; its cause is
presently unknown though it probably is the result of inhomogeneous
data reductions".

Cheers,

IV

[1] Standish, E. M. ""Planet X - No dynamical evidence in the optical
observations" Astronomical Journal vol. 105, no. 5, p. 2000-2006
(1993)
[2] Standish, E. M. " Pluto and Planets X" Completing the Inventory of
the Solar System, Astronomical Society of the Pacific Conference
Proceedings, volume 107, T.W. Rettig and J.M. Hahn, Eds., pp. 163-170
(1996)
http://adsabs.harvard.edu/cgi-bin/np...TML&format

[[referring to the paper
[1] Standish, E. M. ""Planet X - No dynamical evidence in the optical
observations" Astronomical Journal vol. 105, no. 5, p. 2000-2006
(1993)
which argues that outer-planet observations are consistent with a
dynamical model (= general relativity + planetary orbits/masses),
to within reasonable estimates of the accuracy of the observations]]

tttito wrote:
It is a plausible debunking argument, but , as pointed out by others in
this thread, it is not predictive (and hence not falsifiable).

I would say it _is_ both predictive and falsifiable: if the best-fitting
theoretical orbit were to disagree with modern observations by (say)
1 degree [an amount much larger than any reasonable estimate of these
observations' accuracy], then our theoretical model would be wrong.

Of course, some degree of judgement is needed to make a "reasonable
estimate" of the observations' accuracy. This is true for all areas
of observational/experimental science (i.e. all of science except
mathematics).

--
-- "Jonathan Thornburg -- remove -animal to reply"
Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut),
Golm, Germany, "Old Europe" http://www.aei.mpg.de/~jthorn/home.html
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
-- quote by Freire / poster by Oxfam