I am making a near-future setting that takes place in an alternate solar system that's similar to ours (one planet with life, a moon, and other planets without life and their associated moons).
And it's my understanding, even though I'm not a science expert, that the conditions of our solar system, how the earth is situated in relation to the sun and other cosmic bodies, is a "fixed requirement" for life. Making drastic changes to the makeup of our solar system might create a situation that wouldn't have allowed for the hospitable conditions for life that exist on earth.
Now, as I said, this is just what I've caught and I'm not a science person so please correct me if I'm wrong :).
So my question is, how much of the solar system can I change without making life on earth implausible? For example: Does Jupiter have to be a gas giant due to the events that are also related to the conditions we have on earth? Can the earth have three moons without affecting this prospect?
These are not exactly the things that I had in mind for my setting specifically, but I'm just throwing out the kinds of thoughts I'm having.
So in general, what can change and what can't change in order to maintain an earthlike planet in a solar system?