The question Can spaceships really explode in space? very clearly violates our policy on real-world scientific explanations. Why is it still open?
This question was not initially close when it was asked because it was asked before the Real-world science explanations(RWSE) policy was established and for the first 4 years and 3 months it was an on-topic question. Between this post and some more recent posts there were thousands of Star Wars questions burying this post and keeping it out of sight, this meant after the policy it was effectively hidden and not likely that anyone stumbled across it to close it.
The last time this post was acted on was 1 month ago. Where the post went through the close vote queue and was left open. Why it was not closed there, it would seem three users made a mistake.
Before August 2017, it had received little to know attraction and there was only one action preformed on the question after our RWSE policy was established. An upvote, possibly from a user specifically looking for that question, who should've flagged it for closure, however may not have known about our policy. Prior to that, it had received one up-vote and two answers three months prior to the policy and two other answers as well as 3 upvotes two years before the policy.
From the above we can see quite clearly that this post has been hidden from the eyes of the (policy-learned) community, except for one user who had seen it, and maybe some other passers-by. The close vote queue it went through was unsuccessful in closing it (even though it should have closed it). Today however it was successful and has been closed.