fucks me up that by total coincidence the sun and moon's size difference is exactly matched to their difference in distance from us, thus making our beautiful total solar eclipses where you can see the silver threads of the sun's corona possible because the moon just covers the sun completely
The stars (literally) aligned just right for this experience to be possible. It's likely that aliens don't have this
The moon is also absolutely gargantuan by moon standards. It isn't the largest moon in the solar system, but it is BY FAR the largest in comparison with its planet. Ganymede is the largest satellite of Jupiter and the largest moon in the solar system. Its diameter is only about 3.8% of Jupiter's. Titan's radius is 4.4% of Saturn's. Callisto and Io are the next largest in the neighborhood, with 3.4% and 2.6% the diameter of Jupiter respectively.
Our moon is number 5. It is smaller in direct comparison to the above moons. The diameter of the moon is 3475 km. That is a full 27% of the diameter of the Earth. More than a quarter. That's ridiculous. It's unheard of. The universe is large enough that the word unique probably doesn't mean a lot, but this might be about as close as you get.
This has had a huge impact on our planet. Other things aliens might not have are significant tides. One of Mars's dumpy little potatoes wouldn't be able to move oceans the way our moon does.
Our moon has also stabilized our axis to a massive degree. Without her up there our axis would wobble all over the place and our climate would be far more chaotic. Aliens might not be quite so lucky.
I guess what I am really trying to say is that the moon is extremely cool. I like the moon.
Just want to add that the reason we have such a large moon is because a whole planet crashed into proto-Earth. Theia (the planet) and Earth got so superheated by this collision that their component cores fused and the impact jettisoned a lot of material into space. That massive amount of jettisoned material became our moon. So Earth and the moon have very similar composition. This does not seem to be a common method of lunar formation.
what if the answer to the fermi paradox is that life cant exist without a moon like luna
I got a serious beef with the Fermi paradox. There is no Fermi paradox. There stopped being a Fermi paradox once the first radio telescopes went up, and we began to get a true sense of the sheer scale of the universe.
Space is big, empty, and loud. Sunspots can cause enough interference to affect global communications. We’re not even loud enough to talk over our own sun. On our own planet. We can barely communicate with Voyager, and we know exactly where it is and what its signal sounds like.
The Fermi paradox is like doubting the existence of Belfast, because you stood on a windy New York beach shouting towards it and didn’t get an answer.
the thing is that our specific kind of life-bearing planet may very well be a rarity; we're within the Goldilocks zone of a medium-size yellow star (an estimated 75% of stars in the Milky Way galaxy are red dwarfs), and yes, without the Theia event, it's very likely that complex life would never have developed on Earth, because not only does Luna help by keeping the oceans moving and thus causing life-facilitating elements and compounds circulating, but the impact also set the Earth's core spinning and generating a magnetosphere that protects us from solar winds and radiation; Mars's atmosphere of about 0.01 bars and its aridity are partly because it doesn't have these protections
it may be that large satellites of gas giants might be the "safest" place for life to develop, staying warm through tidal heating and protecting the liquid ocean beneath a thick layer of ice; the best places to find life elsewhere in the solar system might very well be Europa, for example, or even in parts of Jupiter's atmosphere
the other thing is that life is probably common in the universe, because we've actually demonstrated in a laboratory that if you just put a bunch of the right elements in water and pump energy into it, you get proteins forming, and four specific nucleotides (adenine, cytosine, guanine, and thymine) are the building blocks of RNA and DNA
not only that, but we've found, like, free-floating clouds of amino acids in deep space
it's improbable to the point of being indistinguishable from impossible that we're the only intelligent life in the universe, and although we might be the only intelligent life in our home star system, it's quite probable that there's life elsewhere here, just not in a place we can easily see it
[ID] Single-panel XKCD comic shows 2 ants on a floor of tiled linoleum, stretching into the distance. They're both facing each other.
The ant on the right says “We've searched dozens of these floor tiles for several common types of pheromone trails. If there were intelligent life up there, we would have seen its messages by now.” /text
A caption at the bottom of the page reads "The world's first ant colony to achieve sentience calls off the search for us." [End ID]




