Some Stack Exchange sites are clearly closely related to each other. For example, "companions" of the physics Stack Exchange site might include:
- History of Science and Mathematics
- Electrical Engineering
- Cross Validated
- Quantum Computing
- And others...
While we don't want to discourage people from asking questions on the physics Stack Exchange site, we ultimately should want questions to be asked wherever we can expect them to find the highest quality possible answers. Oftentimes that's here, but sometimes this simply isn't an appropriate setting for their question (resulting in removal), or the people who would best be suited to answer that question just more commonly frequent one of these "companion" Stack Exchange sites.