на каком конкретном интервале времени предсказания по теории эфемерид JPL DE405 с теоретически заявленной погрешностью начинают расходиться реальными с наблюдениями?
Упомянутые Вами реальные наблюдения имеют отношение к четырем миллиардам лет? Нет. Соответственно, и упомянутое расхождение к этому сроку (и вообще к сроку более чем пара-тройка тысяч лет) не имеет никакого отношения. Теория эфемерид JPL DE405
Munin'ым в процитированном Вами сообщении не упоминалась;
он приводил иные аргументы в пользу экстраполяции предсказаний построения, основанного на законах физики и данных не только астрономического плана.
И какова на Ваш взгляд цена "иных аргументов в пользу экстраполяции предсказаний построения"?
http://arxiv.org/PS_cache/astro-ph/pdf/ ... 2179v1.pdf“Is the Outer Solar System Chaotic?
Wayne B. Hayes
February 4, 2008
Wayne Hayes Computer Science Department University of California
One-sentence summary: Current observational uncertainty in the positions of the Jovian planets precludes
deciding whether or not the outer Solar System is chaotic.
100 word technical summary: The existence of chaos in the system of Jovian planets has been in question for
the past 15 years. Various investigators have found Lyapunov times ranging from about 5 millions years upwards
to infinity, with no clear reason for the discrepancy. In this paper, we resolve the issue. The position of the outer
planets is known to only a few parts in 10 million. We show that, within that observational uncertainty, there
exist Lyapunov timescales in the full range listed above. Thus, the “true” Lyapunov timescale of the outer Solar
System cannot be resolved using current observations.
100 word summary for general public: The orbits of the inner planets (Mercury, Venus, Earth, and Mars)
are practically stable in the sense that none of them will collide or be ejected from the Solar System for the next
few billion years. However, their orbits are chaotic in the sense that we cannot predict their angular positions
within those stable orbits for more than about 20 million years. The picture is less clear for the outer planets
(Jupiter, Saturn, Uranus and Neptune). Again their orbits are practically stable, but it is not known for how long
we can accurately predict their positions within those orbits.”