I've asked a question for which I feel a zero score to be appropriate, and I have no objections to any of the comments posted about it, but it has content, and has received comments, which I feel may remain useful to others asking similar questions for a long time. A couple of keywords (the surname of a major physicist [Poplawski] and a two-word phrase representing a fairly common concept ["galactic rotation"]) that are in it currently appear at the top of more than 400 results in a google search, so I feel that its preservation may save considerable time for persons who are students or researchers in the future, in a way similar to the way in which the marking of questions as duplicates may save them time. Consequently, I'm wondering how long it would be left accessible on the site after its closure.
Duplicate questions are never deleted automatically, and rarely (if ever) deleted manually. They stick around to help direct people to the appropriate question. Often duplicates come up because there is more than one way to ask a question.
For non-duplicate closed questions, they are only auto-deleted in certain situations:
The system will automatically delete any post flagged six times as offensive or spam (3 times on English Language & Usage and The Workplace).
The system will automatically delete closed, unlocked questions with zero or negative score having no positively scored or accepted answers or pending reopen votes, that were closed for any reason other than duplicate nine or more days ago and haven't been edited in the past nine days. (RemoveAbandonedClosed)
The system will automatically delete rejected migrations (questions created as a result of a question from another site being migrated there, and later closed for any reason other than duplicate) that are at least 30 days old. (RemoveRejectedMigrations)
The system will automatically delete negatively-scored, unlocked, and unanswered questions (both open and closed, including as duplicates) that are older than 30 days. (RemoveDeadQuestions)
The system will automatically delete unlocked, unanswered questions older than 365 days on main (non-meta) sites with score of zero (or one, if the owner's account is deleted), fewer than 1.5 views per day on average, and fewer than two comments. (RemoveAbandonedQuestions)
The system will automatically delete any post with a negative score when its owner's account is deleted, unless the post is a question that has at least one positively-scored answer. (This doesn't apply on meta sites.)
The system will automatically delete any post, regardless of score or answers to questions, when its owner's account is destroyed (only done for spammers and blatant trolls).
The system will automatically delete migration stubs (original site copies of questions migrated to other sites, which haven't been rejected by the destination site) that are at least 30 days old. Questions deleted under this criterion still have their revision histories visible to everyone, and links to them redirect to the new question instead of showing an error page. (RemoveMigrationStubs)
Posts with zero or negative score that receive six recommend deletion reviews (four on Stack Overflow) in the low-quality-posts review queue are automatically deleted "from review". Posts can be kicked into this queue either automatically or with very low quality and not an answer flags, and can be removed from the queue if enough Looks OK reviews are cast against them.
Note that except in special circumstances, closed questions with positive scores and/or positively scored or accepted answers and/or pending reopen votes are not auto-deleted.
19 hours ago the system auto-deleted the question. If you hover a cursor over "19 hours ago" (or whatever it says now) you can see the exact time and date in "Zulu" (GMT).
You obviously put quite a lot of thought and effort into formulating this question and composing the post, and I'd hate to see it all go to waste. I'll make some suggestions, though I'm not well-versed on the topic.
This question can be broken into two parts...
I wonder if you can break this down into two (or more) questions, and work the problem step-by-step. First ask a shorter question about the "first part" and wait for answers. It is possible that based on answers to it and discussion in comments, the second part of your question might be better formulated differently.
In Stack Exchange, a "deleted" post is usually not really deleted but just becomes invisible. For a few months you will be able to find it under on own profile page if you list your questions; there may be something called
recently deleted questions. After a month or two (I'm not sure exactly) it won't appear there anymore, but you can still find it by coming back to this meta post and clicking Might the discrepancy between mass and rotation rates, in galaxies, be explained by mass within BHs?.
You can still click
edit on your question and select and copy bits of text to paste into your new question as part of the editing process, but you should not re-post the same question.
Instead I recommend that you try to shorten it substantially and focus on a small subset of the question, and see how that goes first.