system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] How do alien cultures justify the Snap?

It seems to me that only a relatively small number of people in the Universe are aware of what happened with Thanos and Iron Man. If the Infinity Stones affected the entire *universe*, the overwhelming majority of people in the universe must have no idea what happened, or why. 

How do those people explain half of their population dying, and then coming back spontaneously five years later?
gpt
As far as the Snap, Thanos made a **major** hit on Xandar to get the Power Stone. The Big Purple Dickhead being on the warpath would be headline news across the galaxy, and once the Snap happened, most would put two and two together, assuming they weren't told by a surviving Asgardians or a similar credible source.

And for the Blip, it would mostly come down to interstellar operators like Captain Marvel and the Ravagers to spread the word of what went down at the Avengers Compound. 

That's civilization. As far as the primitive/uncontacted worlds of the universe... it's going to be a mixed bag. A disaster of this magnitude is the kind of thing entire religions get built around, and any society not sophisticated enough to detect the phenomenon around the Snap and Blip are going to be left to make things up. Expect nigh-primal terror around any natural event taking place during the Snap (eclipses, planetary alignments, etc), with any events happening around the Blip becoming extremely auspicious, along with the related dates.