When pondering how likely life is to develop on other worlds, or what types of life might develop, we always have to always bear in mind that we currently only have one example to work with. And that example has one extremely unusual attribute, a large moon, at least large in relation to the size of Earth.
There have been speculations over the years about how Earth’s moon may have played a unique role in helping life to develop on this planet, from stabilizing and slowing the Earth’s rotation, giving it a much calmer and more stable climate than it otherwise would have had, to the effects of tidal forces on life’s rhythms.
This article highlights a paper that looks at the moon and its tidal forces possible role in helping life to colonize land: Did A Cosmic Fluke Make Life On Land Possible? | Inside Science.
Terrestrial animals may owe a special debt to the sun and the moon. It may have been their combined pull on ancient Earth’s oceans that helped primitive air-breathing fish gain a toehold on land, new research suggests.
In a new study, published in the journal Proceedings of the Royal Society A, physicist Steven Balbus argues that the gravitational forces generated by the sun and moon would have been conducive to the formation of a vast network of isolated tidal pools during the Devonian Period, between 420 to 360 million years ago, when fish-like vertebrates first clambered out of the sea.
If this theory is true, then terrestrial life might be as rare as a large moon.
Balbus said that developing his theory has made him skeptical of the notion that complex terrestrial life might be common in the universe. “A lot of things had to come together in a strange way on the Earth,” he added.
Maybe the great filter is the absence of a large moon around most rocky planets.
Related articles
- Dynamical, biological, and anthropic consequences of equal lunar and solar angular radii [EPA] (arxiver.wordpress.com)
- Apollo Programme rock samples throw new light on the origins of the moon (independent.co.uk)
- Are we the extra-terrestrials? May be (news.bioscholar.com)
- How the Moon Formed: Lunar Rocks Support Giant Impact Theory (space.com)
- When the Earth Had Two Moons – Issue 13: Symmetry (nautil.us)
SelfAwarePatterns 
I can’t see it being a huge filter, though. The way moons would gravitationally interact means you’re likely to get one moon or none around an Earth-sized planet unless they were all tiny (and even then, Mars’ Phobos is supposed to crash down at some point), and there’s no lack of potential impactors in early solar system formation.
Plus the sheer number of them. Even if only 1 in 100 terrestrial planets had a large moon, that’s still a lot of planets.
LikeLike
You may be right. We don’t currently have any good way to know how many Earth sized planets have Moon sized moons. It’s the only one in our solar system, but the exoplanets being discovered show that we shouldn’t necessarily expect the rest of the universe to match our environment.
LikeLike