In a nutshell the original question was closed as "non-mainstream" physics, but after the meta question, it was reopened.
However, there are suggestions that it should be closed as "too broad":
This is not or less going to require a very lengthy response, probably chapter-of-a-textbook kind of answer to address the question.
Which I find... kind of make sense.
BUT, I also think that this kind of question should be allowed, because
- It can really be answered in brief and essential manner, not just discussed
- The reason why the response can be lengthy is because there are a lot of details, which are important but can also be relegated to another page. So it's not "Questions with too many possible answers or that would require an extremely long answer". The main answer can be short and succinct, the rest are footnote.
- This kind of question is very useful for visitors from Google ( as it can be easily found on Google, because it contains good keywords). The SE answer can be a starting point for the user to build their own answers on top of it.
So when the definition of "too broad" is doing harm to the overall good of the site, shouldn't we revise or or at least articulate what does it means?
When "too broad" is really too broad? Can we make the "too broad" definition good enough so that it won't accidentally kill a lot of good questions?