1.4.Question: Does the size of the solar system change, as does the distance from our Sun to the planets? And what is the reason for this?
Answer: Well, first of all, orbits are stable, because they can be changed only if the object changes. That is, there is the Sun with a certain mass. Of course, the Sun is gradually losing its mass because of solar radiation - this is a process of losing mass. But this change in mass occurs over millions of years, so I don't think that those living now would see a substantive change in the orbits of the planets because of this.
But in principle, the planets themselves increase in size. And, do you what this is primarily due to? Due to meteorites. Over time, more and more of this star dust accumulates. And its basically due to this accumulation on planets, and that they attract this the dust that their mass increases. To some extent it turns out that the sun loses a little mass and the planets gain mass. To some extent there a kind of equilibrium is established, so that the orbits are very stable and don't change.
To change something, you need a very strong, additional external gravitational influence. As long as this does not occur, then nothing will change.