Yeah I think the impact that created the moon is the main reason why there's life on this planet. That impact also mixed up the heavier metals and liberated enough phosphorus making the composition of earth's crust unique. Also the two metal cores fused and made it oversized, prompting the difference between the rotation of the Earth and the core, making the magnetic field that protects our atmosphere possible...
So yeah, I'm definitely not optimistic about life on different planets....
But hey, if it happened once, maybe we'll get to find some remains of another system to which this happened as well. Or maybe, someday, someone else will find ours. Or perhaps gravity is the only force keeping us from drifting off the surface of our rock, preventing us from falling into the darkest void for eternity, with the vain hope that your frozen corpse will someday land in someone else's yard, like a cosmic frisbee.
The universe is large enough that similar combinations of events could have happened elsewhere too. But it's also large enough that those places are most likely further from us than our species will ever travel.
And I'm sure the strong tidal pull likely had an accelerating effect on the early stages of the emergence of life, since the first steps would have basically had to crash into each other in water without having any other way to move. There are many other ways for that to happen on the "millions of years" time scale, but the amount the moon moves our water has got to have had a notable effect.
One of the current theories of life formation involves thermal vents, which provide energy and motion (and necessary chemicals) without any need for lunar tides.
In the fifth or sixth book of the Foundation series they follow a map to Earth that mentions a planet with huge rings and a planet circled by a giant moon. Throughout the universe, this combination was so unique you could identify the home of humanity among trillions of planets.
And it shows how Asimov had zero conception of how ridiculously huge the galaxy is, though that's just the storylines being a product of their time, probably.
But the moon size thing isn’t a coincidence, thats part of what makes solar eclipses so rare, the moon needs to be at the correct distance when it passes in front of the sun or it isn’t as impressive, and it does do that some times.
Total* solar eclipses. Mars has solar eclipses, just not very impressive ones since the shadows are so small, but you could actually look directly at the sun to see the shadow at that distance, without fucking up your eyes
Ceres is the issue. People are pissed that they learnt the list of planets and now it's different, but don't realise the only viable options were to either drop the last one or add a bunch of them, some right in the middle.
I like to imagine an alien "watcher" with a lifespan measured in billions of years who has been hanging out in our solar system since its formation. It finally decides to contact us humans and tells us that it saw our moon being formed from another planet smashing into Earth billions of years ago. "Yeah, we know - wanna see the movie we created showing it?"
I love that one of the characters in Iain Banks' "Transition" tries to find aliens by spotting airtight -looking vessels (ships, vans,..) during solar eclipses, for this exact reason.
Hell yes it was weird as hell! It was also the most conceptually mind boggling (with all the gender and sexual fluidity on top of everything else). I felt from style of writing and tone it was very personal and intimate, guess thats why I liked it so much.
The weirdest book to me was feersum endshin (sp?), but I mean, we're reading Banks "it was the day my Grandmother exploded", so....
Sometimes I wonder if the moons size / existence is one of the reasons why life is even possible in the first place - Maybe aliens would know what it's like to have a moon a quarter the diameter of the home planet because otherwise life has no chance, maybe life is even more likely on dual planet systems like Pluto and Cheron, maybe that's already too similar in size and life has no chance, maybe the median sentient creature in the universe has experienced a tide, or maybe not - anyways I dunno that much about exoplanets or astronomy in general so every thing I've said might be completely bonkers xD
It sounds more like the moon is just earth spare parts. Like when I put things back together. Always a bin of extras that hang around in the back of the truck, sliding around and what not.
There's also an argument that the moon isn't actually a moon since it doesn't actually orbit around the Earth. If you look at their respective orbits, the moon and Earth kind of shift places like a spinning helix pattern and the orbit of the moon is more tied to the sun than the Earth.
I haven't watched this all the way through, but it looks to largely cover the same material. I don't know how common this is among moons, but I think it makes Earth's relationship with its moon that much more special.