A guess as to how we obtained the moon
There are basically a few theories out there on how we got a moon this large rotating around the Earth.
Mine is probably unique.
I think a planet the size of Neptune was destroyed early in our Solar System’s history. Whether it was hit with a planet sized comet or some other reason, the planet blew apart. Since the planet was hot, it was mostly semi-liquid molten lava. The lava was liquid. It blew into hot liquid lava balls of all sizes and scattered throughout the solar system. This produced many moons all over the solar system that were attracted basically to the gas giants. I think Earth was one of those balls. The Moon was another.
The Moon early on was a planet not a moon. It had atmosphere and life. It probably had shallow oceans as well. It was where it is right now orbiting the Sun at approximately 90 million miles out.
‘The Earth settled around Saturn as a moon. Then the unthinkable happened. A giant planet several times the size of Jupiter fell into the gravity pool of the Sun. It came down through the system at an odd angle to the plane of planets. It knocked Neptune and Uranus around. It dragged moons out of orbits from the two gas giants Saturn and Jupiter. As it plunged towards the Sun it dragged moons behind it. Also a huge tail of asteroids spun out from behind it. The world had a lot of water on it. This sprayed out the tail. Coating the moons dragged behind with water. Much more water than they originally had.
It went all the way in and it slingshot out at tremendous speeds. The worlds in the tail were scattered as it gained velocity it lost the tail. The Earth was attracted to the small body rotating around the Sun. This was the Moon. The Moon was strong enough or the hold on Earth was weak enough that it grabbed Earth away from the tail. A lot of the tail plastered the Earth and the Moon. The oceans were in the tail as well. Earth gathered the water more to us than to the Moon. The moon was plastered with asteroids. At first the two bodies spun around each other. For the Earth was much lighter than it is today. Most of the water came to Earth and a lot of asteroids floated in the semifrozen water. These were attracted to and dropped onto the Earth and sank in the oceans that formed. The atmosphere was much thicker back then. Mainly because we inherited the atmosphere from the tail.
Gradually the heavier gravity and size of the new planet Earth caused the moon to form an orbit around our planet. It still fought tooth and nail as the Moon’s gravity caused tides. The reason it did not slingshot off was the immense amount of free water in space from the tail of the large planet. I think the large planet either broke out of the Sun’s gravity field or is way out there past Neptune somewhere. Gradually most of the free water found its way to Earth.
The water spread all over the solar system. I think the asteroid belt is full of water.
Mars was formed in its orbit at about the same time. I think Mercury was the same way, though both of these planets might have been a result of the initial explosion. I think Mercury is mostly from the core material of the original larger planet that exploded.