As part of a quest to add some solid science fiction to my catalog, I’m working on a story that takes place on and around a planet which is not Earth, yet exists in the same universe as Earth. This planet cannot support humans, but has an ecosystem and atmosphere that supports native life. The humans from Earth wind up there for assorted reasons, and have to eat the native things to survive.
It’s a curious thing, deciding how a planet should work and without using “because magic” to explain the differences. Plants on Earth use chlorophyll, which absorbs red light so you see green (this is, of course, a gross oversimplification).
What if a different planet’s star doesn’t offer red light, or doesn’t offer as much as it does blue light? The plants might evolve differently, and you’d wind up with orange ones thriving. That one small change could ripple through the ecosystem in a zillion tiny ways. Or it might have no real effect whatsoever, because the process that replaced chlorophyll might work exactly the same from the perspective of the things eating it.
How does one decide whether to tinker with the basic assumptions of life, or to leave them alone in the name of having fewer things to point out as specifically different? I’m not concerned about explaining why this aspect is different, because it doesn’t matter. When something doesn’t matter, explanations are unnecessary and annoying.
The question is: Where is the line? At what point does making something strange become a gag or a gimmick, an oddity too far? Sadly, I’m not sure there’s a one-size-fits-all answer. I still intend to pursue it.