I'm currently working on a world for a fantasy novel. For the sake of this discussion, we can assume it's low to no magic at all, and has no higher-intelligence interference, such as creator races, aliens, or gods. The technological level of this world is similar to our Bronze Age.
Structurally, we can imagine our solar system, Earth, and its moon.
My question: I plan on having my moon coated in mushrooms or other living organisms that could shoot something, be it spores or debris or anything else in between, towards the host planet in order to spread spores there. How plausible would this be? I'm not looking for 100% scientific accuracy here, just enough to make it plausible. The nature of the flora inhabiting this moon, and the way through which it shoots off planet is not vitally important, I'm good with most options.
- What situation would I need to create in order to have a moon with an atmosphere that could be infested with fungus and other life-forms, that could be capable of "seeding" the host planet on a cyclical basis?
- reality check - Is This Living Planet Plausible? - Worldbuilding Stack Exchange
- biology - Is a planet sized creature possible? - Worldbuilding Stack Exchange
- biology - Could a creature like the brethren moons exist in reality? - Worldbuilding Stack Exchange
Some discuss heavy numbers, which is something that in general confuses me a lot, and I have problems understanding. Others concern themselves with living planets and the way they could potentially move across space, which is not exactly what I'm looking for. Another one is quite close to what I intend, but not quite, as it discusses how a planet of this sort could shoot its spores to other solar systems, while I'm simply aiming for a Moon to Earth situation.