Seeing how objects collide with planets, it is easy to see how you can simply make the connection that an object collided with the planet, debris was ejected back into space, and a large enough piece became a moon. Just look at how scarred the face of the moon is:
Scars from collisions on the face of the moon
Astronomers will theorize on all the possibilities, but what really appears to be happening is a slowdown of the idea of figuring out what happened. There is so much going on in the universe and all the new technology providing telescopes to view the universe have essentially left the challenge of figuring out how the moon came into existence as something few are interested in pursuing.
What is unfortunate, is it is possible legacy astronomy is wrong about how the moons form and anchor or moor their motion around the planets. If they are wrong, it could mean their whole Protoplanet theory is incorrect. From there, lots of other assumptions that build upon the current theory could also be in jeopardy. Unfortunately, all the new toys of technology make solving the problem undesirable, this could leave the door open for a new technology or theory of how comets, planets and moons evolve.
If you use porphemes as a way to view the word MOON it says MOor motiON. As if it is saying the celestial body already exists, you just need to realize how it anchors or moors its motion to the planet. As we go back and look at how planetesimals form into protoplanets is it possible the term planetesimal should be changed to celestimals, to reflect the possibility that planetesimals can develop into any type of celestial body, not just a planet.
A new science called celestial astronomy poses a new theory about how the star system forms and how comets become the planets and moons through a process called binding. The main processes of disks, planetesimals, and protoplanets are still there but with slight changes to reflect the function of a dynamic state system versus a static state system as in legacy astronomy.
Before moving on to explain how all the planets form and how you can see a repeating pattern that describes a planetary lifecycle, celestial astronomy describes a concept called lunar accumulation, which explains how the moons moor their motion to the planet. Just like it is important to develop repeatable, definable patterns that allow to explain and predict the evolutionary process for planets, the same needs to be done for the moons.
What is also interesting is how our moon does not have a name but all the other moons do. It makes you wonder what all the people who named the celestial bodies knew in order to derive all their names. Is it possible they were HETLAU? It makes you wonder when using porphemes you realize EARTH says hEAR truTH!