For questions about the fictitious in-universe astronomy found in works of speculative fiction. Questions purely concerning real-world astronomy are off-topic but can be asked on Astronomy.SE (

Use this tag if your question is about the fictional astronomy found in the universe of a work of science fiction or fantasy. Note that this site is about fiction, not about real-world astronomy, for those questions see Astronomy.

If your question is about:

  • how the in-universe astronomy relates to real-world astronomy, ask here, but do not necessarily expect answers from experts on real-world astronomy.
  • real-world astronomy, your question is off-topic here. You might consider asking on the Astronomy Stack Exchange or the Physics Stack Exchange.

Please see this discussion thread for more detail about our policy on science questions.