A final explanation for the question of Mars' orbital change(1/5)
The author has actually explained this issue in his work.
But there are still people who question - "You're too vague" and "The changes in Mars' orbit are much bigger than you think!"
Well, since the author’s simple explanation is not strong enough, let’s take a look at the serious things. Anyway, since this book has been written so far, there are a lot of bugs in this book, and there are many people who use junior and senior high school physics to pick on it.
The following is the content of the article:
Long-term integrations and stability of ary orbits in our Solar system
Abstract
We present the results of very long-term numerical integrations of ary orbital motions over 109 -yr time-spans including all nine s.
A quick inspection of our numerical data shows that the ary motion�
�
� at least in our simple dynamic model�
�
� seems to be quite stable even over this very long time-span.
A closer look at the lowest-frequency oscillations using a low-pass filter shows us the potentially diffusion character of terrestrial ary motion�
�
� especially that of Mercury.
The behaviour of the eccentricity of Mercury in our integrations is qualitatively similar to the results from Jacques Laskar's secular perturbation theory (e.
g.
emax�
�� 0.
35 over �
��± 4 Gyr).
However�
�
� there are no apparent secular increases of eccentricity or inclination in any orbital elements of the s�
�
� which may be revealed by still longer-term numerical integrations.
We have also performed a couple of trial integrations including motions of the outer five s over the duration of ± 5 × 1010 yr.
The result indicates that the three major resonances in the Neptune�
�Pluto system have been maintained over the 1011-yr time-span.
1 Introduction
1.1Definition of the problem
The question of the stability of our Solar system has been debated over several hundred years, since the era of Newton. The problem has attracted many famous mathematicians over the years and has played a central role in the development of non-linear dynamics and chaos theory. However, we do not yet have a definite answer to the question of whether our Solar system is stable or not. This is partly a result of the fact that the definition of the term ‘stability’ is vague when it is used in relation to the problem of ary motion in the Solar system. Actually it is not easy to give a clear, rigorous and physically meaningful definition of the stability of our Solar system.
Among many definitions of stability�
�
� here we adopt the Hill definition (Gladman 1993): actually this is not a definition of stability�
�
� but of instability.
We define a system as ing unstable when a close encounter occurs somewhere in the system�
�
� starting from a certain initial configuration (Chambers�
�
� Wetherill & Boss 1996; Ito & Tanikawa 1999).
A system is defined as experiencing a close encounter when two bodies approach one another within an area of the larger Hill radius.
Otherwise the system is defined as being stable.
Henceforward we state that our ary system is dynamically stable if no close encounter happens during the age of our Solar system�
�
� about ±5 Gyr.
Incidentally�
�
� this definition may be replaced by one in which an occurrence of any orbital crossing between either of a pair of s takes place.
This is because we know from experience that an orbital crossing is very likely to lead to a close encounter in ary and ary systems (Yoshinaga�
�
� Kokubo & Makino 1999).
Of course this statement cannot be simply applied to systems with stable orbital resonances such as the Neptune�
�Pluto system.
1.2Previous studies and aims of this research
In addition to the vagueness of the concept of stability, the s in our Solar system show a character typical of dynamical chaos (Sussman & Wisdom 1988, 1992). The cause of this chaotic behaviour is now partly understood as being a result of resonance overlapping (Murray & Holman 1999; Lecar, Franklin & Holman 2001). However, it would require integrating over an ensemble of ary systems including all nine s for a period covering several 10 Gyr to thoroughly understand the long-term evolution of ary orbits, since chaotic dynamical systems are characterized by their strong dependence on initial conditions.
From that point of view�
�
� many of the previous long-term numerical integrations included only the outer five s (Sussman & Wisdom 1988; Kinoshita & Nakai 1996).
This is because the orbital periods of the outer s are so much longer than those of the inner four s that it is much easier to follow the system for a given integration period.
At present�
�
� the longest numerical integrations published in journals are those of Duncan & Lissauer (1998).
Although their main target was the effect of post-main-sequence solar mass loss on the stability of ary orbits�
�
� they performed many integrations covering up to �
��1011 yr of the orbital motions of the four jovian s.
The initial orbital elements and masses of s are the same as those of our Solar system in Duncan & Lissauer's paper�
�
� but they decrease the mass of the Sun gradually in their numerical experiments.
This is because they consider the effect of post-main-sequence solar mass loss in the paper.
Consequently�
�
� they found that the crossing time-scale of ary orbits�
�
� which can be a typical indicator of the instability time-scale�
�
� is quite sensitive to the rate of mass decrease of the Sun.
When the mass of the Sun is close to its present value�
�
� the jovian s remain stable over 1010 yr�
�
� or perhaps longer.
Duncan & Lissauer also performed four similar experiments on the orbital motion of seven s (Venus to Neptune)�
�
� which cover a span of �
��109 yr.
To be continued...