A while ago I read what was supposedly the original plan for the ending of Mass Effect. In the world of Mass Effect, there is a specific technology that underpins essentially the entire culture and economy in the world. It turns out that this technology hastens the end of the Universe, and the “big-bad” of the series comes along to destroy civilization, to stop the universe from ending.
This is obviously not the ending that the video game series ended up pursuing but it’s something that I would like to implement. In my hard science fiction setting, humanity has settled in a new solar system after leaving Earth centuries ago. Earth has been relegated to the place of myth. There is no FTL travel, no artificial gravity. My question, is what kind of theoretical technology we could envision that would serve such an integral role in this society. As far as technology goes, I’m willing to make the leap to some kind of handwavium or unobtanium type fuel source or something but I want it to be realistic enough that there isn’t much suspension of disbelief required on the part of the reader. Originally my thought was having some kind of space Stargate type thing, where ships going through these wormhole-portal things is how the interstellar economies function (I also had the idea that maybe, unknown to the inhabitants of this civilization, the star gates a portals through time as well as space). And then travel through these portals has some kind of deleterious effects on the universe. I ended up deciding against going with this wormhole/portal/stargate idea because it is such a common trope in science fiction, I wanted to do something a little bit different (especially since I conceived of these gates as being remnants of an ancient alien civilization and I have become a little tired of the ancient aliens trope, to be honest).
Is there another hypothetical type of technology that human beings could develop that wouldn’t stretch suspension of disbelief too far?