Here's a brief article I wrote for work.
A view of the Moon from the Northern Hemisphere. Photo: perry-pics/Flickr/CC BY-SA 2.0
The Moon is old
The Moon is 4.2 billion years old. The Earth is just 4.5 billion years old and our entire solar system 4.6. The Moon is very old, older than all of life, in fact. From the first pieces of self-replicating molecules, to the first cells, to all of our ancestors — the Moon has been in the sky looking down, and life up at it.
The Moon is a piece of baby Earth shot off in a near fatal wound
At formation, the early Earth was bleak and scorched, volcanic and Moonless, a period known as the Hadean (appropriately, named after the Greek underworld). It was basically like that planet from Star Wars nobody remembers, where Obi Wan messed up Anakin. The Earth was just a molten baby, when one day through the darkness loomed a gargantuan rock the size of Mars, named Theia. Theia was travelling towards Earth at 4 km per second when Blam! Theia collided with Earth. Like those uninspiring threats: “I’m going to hit you so hard your grandchildren will have black eyes”, Theia hit Earth so hard it melted Earth’s crust from rock back into a sea of magma, and created an atmosphere of rock vapour. Youch. The rocky fragments from Earth and Theia that shot out into space formed a disk (like Saturn’s) that orbited around Earth, and after around a month (‘month’ coincidentally derived from the word ‘Moon’), coalesced to form the baby Moon.
The dark side of the Moon is less volatile
The bright, or visible, side of the Moon has 31% of its face pockmarked by the prehistoric remnants of volcanoes (yes the Moon had volcanoes, imagine looking up into the night sky and seeing lava pluming from a volcano on the Moon). However, just 2% of the dark side of the Moon has such volcanic activity. Why? Go look it up ;)
Honeymoon. Photo: Arijit_Roy/Flickr/CC BY-NC-ND 2.0
The Moon is a natural satellite
Satellites are objects that orbit planets. Our solar system as over 100 natural satellites. Skeptical and think the Moon might be another planet or a star? Watch the official debate
The Moon pulls at Earth’s heartstrings
The Moon has around 1/81st the mass of Earth. It carries some clout. As such, as the Moon travels around the Earth it literally pulls up the surface water and oceans in a bulge towards it. Not only does the Moon pull at Earth’s water, but its crust too. The friction created by the Moon’s pull on the crust creates heat. Getting hungry for pizza yet?
The Moon balloons testes
Male streamlined spinefoot, a species of fish, have the hormones in their testes fluctuate with the phase and proximity of the moon. In a closely related species, the Moon also influences the fish’s melatonin, a sleep-regulating hormone.
If you want to split hairs, the Earth is juggling a handful of moons
The Moon is technically Earth’s only natural satellite, but some near-Earth objects orbit our planet in a semi-regular, semi-stable fashion. In fact, according to some astrophysicists, there is a roughly one metre natural satellite orbiting Earth at any one time.
The word ‘lunatic’ is derived from the word for the Moon
The Latin word for the Moon, ‘luna’, became associated with strange and erratic behaviour in people (from the belief that the moon caused insanity), creating ‘lunaticus’, which evolved into ‘lunatique’ from Old French, and finally to ‘Lunatic’.