Do you think any aliens exist in the universe?

[Spacetime Inhabitant]

The book I referred to used the definition of L from the Sagan modified version of the equation, where L = fraction of a planetary lifetime graced by a technological civilization. This yields a theoretically larger number, although of unknown actual size.

 

[Shadowy Man]

The idea that large tides may be *necessary* for the development of intelligent/technological life, seems even more of a stretch based on extremely little information.

That's true, but unavoidable; By necessity all of our thoughts on the subject are highly speculative and woolly, and are more likely than not to be contradicted by future observations and data. It's hard to imagine a scenario in which moons like ours are common, though, however they may arise.

Personally, I don’t think there’s enough information to make a statement like “hard to imagine a scenario in which moons like ours are common”. My expertise is not in planetary system formation but my understanding is that in the early days of a protoplanetary disk, many objects may form. Some may collide, some may be ejected.l due to the developing gravitational dynamics at play.

The current idea for the moon’s formation was the collision between earth and a mars-sized object. We know for sure that earth sized and mars sized objects can form (because of the existence of earth and mars in the solar system) so for me it isn’t “hard to imagine” a scenario in which two of these objects collide.

There just isn’t a large enough sample size to tease out the underlying probabilities. Let’s say there was a 50% chance of a large moon forming, then the fact that of the three major rocky planets only one has a large moon is eminently consistent with such a probability. It is consistent with a wide variety of (as yet unknown) probability distributions.

I don’t know on what basis you can appear so sure as to the rarity of large moons like the earth’s. If there’s a study or paper you can point me to that discusses this I would happily read it. As I said it’s not my expertise. But I do know from my experience that dealing with have call “small number statistics” can lead one to erroneous conclusions. And I can give a specific example from my research if you’re interested.