Most stories that take place across lightyears of space exist in fictional worlds where some of our best well known laws of physics are broken. But if you want a picture of what you future might really be like without elements of fantasy mixed in you'll need to look a lot harder. Faster-than-light (FTL) effects are especially unlikely because regardless of the mechanism, special relativity tells us it will violate causality and require infinite energy for all known matter.

This shelve is for collecting books that:
- span lightyears
- are set in a universe that could be our own
- obeying the laws of special relativity, general relativity, thermodynamics, conservation of momentum and quantum mechanics
- also anything else considered the bedrock of science
- especially no FTL travel, FTL communication, wormholes, accessing parallel worlds or time travel

Also only include full books, not short stories.