Sun cults come and go,
and the stars seem so distant that early humans relegated them to the realm of the dead, or dreams.
But as the brightest object in the night sky, and owning a schedule a civilization could set its watch by, the moon is Earth’s constant companion.
The moon was essential to early cultures, a willing participant in the ever-fruitful nocturnal hunts.
And the moon’s obvious relation to menstrual cycles led many early humans to assume the Moon was the mother figure of the night sky.
In fact, some historians claim the basic lunar calendar is responsible for the creation of agrarian societies, and hence, the whole churning ball of wax we live in today.
But the first to propose a serious scientific explanation for the existence of the moon was George Darwin, fifth child of the famous Emma and Charles. In 1896, he proposed that the centrifugal force of an early spinning Earth had sent its newly cooled mantle flying off into space, where it formed its own small object.
Later studies, confirmed by Soviet Russia’s extensive moon study, would back up his initial suspicion – the Moon used to orbit much closer to us, and even now, every orbit is slightly further away than the previous one.

But Darwin could never get the math to work out quite right – and his theory lay dormant and unproven.
It was only in 1946 that Harvard geologist Reginald Daly would challenge Darwin’s explanation, using Newtonian physics to suggest an external factor –
a cataclysmic collision
with another planetoid.
(Daly would later go to justify his other famous theory – plate tectonics – by claiming it was an inevitable result of the moon being formed by a collision with another planet.)
Nicknamed Theia – after the Titan Theia, who gave birth to the Moon in Greek mythology –

a smaller dwarf planet, one of many stray objects that filled our still-forming solar system,supposedly smashed into our fledgling home around four and half billion years ago,
causing an almost unimaginably destructive event, a collision so intense and violent that the iron cores of the planets actually mixed together.
The resulting floating detritus formed a kind of disc around the now damaged Earth and eventually – researchers speculate anywhere between a month and a 100 years – formed into the small object that orbits us now.

Additionally, remarkable recent research in gravitational physics suggests that the isotopic fingerprints (essentially, the chemical DNA of heavenly bodies) of the moon and the Earth are nearly identical, meaning that the material that was shot into space from the collision – and hence, eventually the moon itself– was mostly made up of Earth’s mantle that was sent skyward in the collision.
Next time you’re out for a walk at night and you look up, say hello to the old neighborhood for me.