While going through some of the old astro.SE questions, I've noticed some astrobiology questions among them. They were certainly on-topic there, and I've seen threads that indicate most of what was on-topic there is to be taken as on-topic here, but there might be objections that it is more in the realm of biology than physics.
I see three cases:
- Astrobiology is decidedly on-topic.
- Astrobiology is decidedly off-topic.
- This is best handled case-by-case. For instance, questions about non-carbon-based life are better handled by biologists, while other questions might deal more with the temperatures and solar winds we'd expect exoplanets to experience in certain environments.
Opinions? Was this already discussed elsewhere?