Luna

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.
  
  Earth is and always has been the giant beaker of chemicals that has one of those magnetic stirrers in it, thanks to the moon.
  
  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.
- I believe there is but it's also kind of unnecessary to think about it since regardless of where it is past Mars and Venus it's unreachable anyway.

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.
It's a weird book but I'm glad I read it.
- Well, Foundation and Earth is the fifth book of the Foundation trilogy... of course it's weird.
  
  Ah, the Douglas Adams approach.
  
  Similar to the five book Hitchhiker's Guide trilogy.
- And the idea of such a big moon was part of why it was largely thought of as an unfounded myth.
  
  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.

Well technically Charon is bigger relative to its parent body but, y'know, Pluto isn't a planet...
- That's messed up, right?
  
  Found Gus.
  
  I've heard it both ways.
- A-ha! So the real reason Pluto got degraded was so Earth could keep it's biggest moon status!
  
  Big Moon has gotta be behind this!
- Twin planets. Caron and Plato. Downgraded to dwarves because NDG sucks milky ways.
  
  He might suck, but you know it wasn't his decision right?
  
  Charon is still a moon, nobody upgraded it to dwarf planet.

Due to tidal effects the moon is slowly getting further away from the earth, so we're living at just the right time to see such spectacular eclipses
- Just add some really massive thrusters to the Artemis 3 payload manifest and nudge it back every so often
  
  Or detonate a nuclear waste dump to send it flying off into deep space. We're 25 years overdue already.

So evangelion was right?
Jokes aside, the probability of moonlike-moons forming in earthlike-planets should be added to drake's equation and see what that begets.
Might explain a lot of the silence, at least for life as we know it
- The drake equation is a bogus probability that really means ultimately nothing. I wouldn't put stock in anything it says.
  
  Why is that?

The Whack theory still has some important exceptions, which is why there’s a Double-Whack theory, which also has exceptions.
“The moon was created this way” is an opinion.
- "hypothesis", rather than "opinion", no?
  
  Hypothesis:
  A tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation.
  Something taken to be true for the purpose of argument or investigation; an assumption.
  The antecedent of a conditional statement.
  I'd agree if it was stated as "current thinking holds that" or "one theory is" not just "here's how it happened". The latter is an opinion.

WE LIKE THE MOON!

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
  
  Do they bother calling them "eclipses" or "transits?" Like we don't say Mercury or Venus eclipse the sun.

There are some schools of thought that say that a large moon like ours should be a part of the Drake Equation, because without which life would have a very hard time even on supposed “garden planets”.
Another factor that is likely to affect civilizations is an easy source of energy, like oil. We got lucky, in that the evolutionary development in Lignin in plants - and the several million years needed for bacteria to catch up and be able to break it down - are what created those massive deposits of organic matter that became trapped deep in the Earth and modified into oil. Without that oil we are unlikely to have reached several milestones, including transportation, population levels, trade, high technology, and even access to space. And this would start affecting us several hundred years back, with steam engines.
- But maybe that's what normal civilizations go though before leaving their planet, and the abundant access to oil will cause us to destroy earth before we can leave it 🤔
  
  I recall one paper that tried to analyze how long it would have taken to go from a pre-coal civilization in the 1800s to spaceflight, all without hydrocarbons from the ground, and they estimated over 8,000 years to develop sufficient biological sources of hydrocarbons that could advance tech enough to just get into orbit. And the planetary population would have never exceeded 2B in the process. Oil, gas, and coal have done a shitton to enable technology. Even something as simple as electricity requires significant hydrocarbons Just in the infrastructure, not to mention the production of electricity itself.

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.
- That was, perhaps, the weirdest, Iain M. Banks book I've read.
  
  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.

Our moon is only the largest moon to planet ratio in our solar system if you discount Pluto as a planet.
- Fun fact: if Luna was only about 30% heavier than it is currently, the Earth's barycenter would lie outside of Earth, which would potentially make Earth not count as a planet by the modern IAU definition.
  
  The real question is... Could such a situation be inhabitable, could life evolve on such a world?

The Moon by Dark Moor

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.

Forgetting Pluto and Charon, drag sees.
- Those are more of a binary planet than a planet and satellite, to be fair. And that's even before we get into the whole planet vs dwarf planet debate.
  (For the record, I think Ceres should also count as a planet)
  
  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.