The improbability of exact circular tracks is one reason.However, less eccentric ellipses are to be expected. First of all, theoretically due to the shape of the gravitational field with the attraction inversely proportional to the square of the distance, the mathematically possible orbits are all cone sections, which includes extremely long ellipses, which can be almost parallel to the Cone side can cut and even non-closed tracks, parabolas or hyperboles, which could be counted as one-time visitors.
Comets that occur in centuries-long time intervals have highly eccentric elliptical orbits, but the planetary orbits are more circular with low eccentricity.The fact that most planetary orbits do not have an exact circular shape is not only explained by the extremely special and therefore rare cut exactly pervertical to the cone axis, the joint formation of the sun and planets of a dust cloud from which they form like At the beginning, even expect circular tracks rather than very elliptical tracks. Planets, which do not arise like the sun in the center, but from inhomogeneities in outer places as “crystallization germs”, all initially moved within the dust disk still in circular orbits.
Anything that has tendencies within an originally formed dust disk already in the formation phase deviating from the circular movement, would shift accordingly further inwards or outwards or even drift out of the disk from which the solar system itself itself has formed.
Mercury has the greatest eccentricity of orbits in our solar system at about 0.2 – which is not as large a circle as with comets.Mercury’s orbit has axes whose lengths are 0.3 AE and 0.47 AE. The smallest eccentricity has Venus with 0.0067, in which the sun distance changes only between 0.718 and 0.728 AU, but exact circular orbits are very unlikely already due to resonances of planetary orbits, disturbing resonances lead to higher eccentricities and as the name suggests in extreme cases to leave a stable track.
One has to remember that planets and thus their orbits did not suddenly arise, if one reads from the age of the Earth as 4.5 billion years, then this is only a gross estimate on the order of magnitude, the solar system formation was still in the process of being of a longer order of magnitude.So long that one has to speak primarily of the orbits of gas and dust concentrations, which must ultimately have had a constructive influence on each other, since any destructive disturbance of the conurbation to a planet counteracts and the concentration would have been dissolved. This may have been more common even in the course of solar system formation. In any case, a planet can only arise in place of a long-term stable orbit and which has rather less eccentricity, but 0 – circular – is extremely unlikely due to the mutual influence.
NEWSFLASH: According to Harald Lesch, this stability was last in danger about 70,000 years ago.
On the other hand, cosmological events such as the “collision” of entire galaxies can be contrasted, in which, despite the massive number of solar systems involved, one assumes extremely low probability of solar or even planetary collisions, because so densely the light of galaxies is optical, there are already within every single galaxy enormous distance between solar systems, which we see with the naked eye, for example, that the Milky Way – stars from our own galaxy – do not illuminate the night sky shining brightly brightly , but are just a milky ribbon in the sky.
What is to be expected in the distant future – in 2 billion years – is the fusion of the central black holes of our galaxy and the Milky Way and a transformation over the next billion years into a new spiral galaxy or other shape.Our solar system still exists, but the sun would be so much brighter and the Earth so much hotter that the Earth would no longer be part of the habitable zone of our solar system.
If humanity then has brought it to any moon, or better yet into other solar systems, we would still need luck not to get into the inner area of the galaxies, which makes life impossible.Thrown out into the vastness of the empty space, on the other hand, the solar system could become even safer against such disturbances, but also much more cut off.