I have noticed the "unclear what you're asking" close reason misused multiple times (if asked, I can provide links, but I can think of many). However, there was one recent case that made me write this post. Increasing The Momentum Of A Photon has four close votes saying the question is unclear. The text of the question is

Is there another way to increase a photon's momentum other than increasing its energy?

It also has an answer.

Guys, this question is perfectly clear! If the answer is "no", that does not mean it is unclear. If it's got an answer that's legitimate (i.e., not spam, vlq, etc) it's probably not unclear. I've seen close votes on other questions in spite of these two things many times, and I'd just like to write a community-wide reminder and see what the rational of the close votes there was.

So: thoughts? Is the unclear close reason being used for a purpose I'm not seeing here?

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    $\begingroup$ If I recall correctly the original version of that question said something different and something that warranted those votes $\endgroup$ Commented Jul 1, 2017 at 6:37
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    $\begingroup$ For the record, the close review was completed with 3 close and 2 leave open votes. The latter 3 of the five votes to close were cast after the question was last edited. On this post itself, it is not clear to me if you want to discuss this specific question or the more general (and, imo, wrong) idea that the presence of an answer means a question is not unclear. $\endgroup$
    – ACuriousMind Mod
    Commented Jul 1, 2017 at 9:44
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    $\begingroup$ Since it's been closed, I voted to reopen it because it's less unclear than when it was originally posted. I still think there ought to be a messaging system for Qs that were edited after close votes were cast, but I think it's kinda difficult. $\endgroup$
    – Kyle Kanos
    Commented Jul 1, 2017 at 11:21
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    $\begingroup$ Also, for the record, it can be the case that one person interprets the question as asking about X & answers as such while others don't see it that way and VTC as unclear because the interpretation of what is being asked isn't clear. $\endgroup$
    – Kyle Kanos
    Commented Jul 1, 2017 at 13:55
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    $\begingroup$ I voted to close the question as unclear because the energy and momentum of a photon are linearly related and one cannot be changed without affecting the other. I interpreted the question this way, "If x = ky, is there another way to increase y other than changing x". With this interpretation, the question sounds very absurd. Yet it had a valid answer and shouldn't have been closed. I apologise for being a little careless while casting the vote. $\endgroup$
    – Yashas
    Commented Jul 1, 2017 at 16:57

3 Answers 3


Is the unclear close reason being used for a purpose I'm not seeing here?

I saw the question right after it was posted and offered a comment to the OP. The original post is (from the edit history):

IF! a photon could go faster than the speed of light, would its momentum increase? And also, is there another way to increase a photon's momentum other than increasing its energy?

I don't know how to check but it's entirely possible that the close votes (for being unclear) were cast before the OP edited the question in response to one or more comments.

After the edit, I removed my comment but I see one is still there regarding the original post.

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    $\begingroup$ That's what it looked like when I cast my vote. $\endgroup$
    – Kyle Kanos
    Commented Jul 1, 2017 at 11:17
  • $\begingroup$ Probably same as @KyleKanos $\endgroup$ Commented Jul 1, 2017 at 19:27
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    $\begingroup$ The comment above by @ACuriousMind shows that 3 of the 5 close votes were cast after the edit was made to the question. The link does not indicate whether these votes were cast for the reason unclear what you are asking but the comments above by Yashas and Hritik confirm that this was their reason. $\endgroup$ Commented Jul 7, 2017 at 22:01

I find myself in disagreement with the premise of the question. Simply because a question has one or more answers does not make it clear. Moreover, simply because the statement of the question is clear does not in itself make the meaning of the question clear.

As an absurd example, consider the question “Is the sky blue because hippopotami are pink?” (The situation I'm illustrating is similar to the example of the OP in that the question is short, with limited context.) Certainly the statement is clear but what on Earth does this question mean?

It may well be that one contributor will answer as to why the sky is blue, another as to why hippopotami are pink, and even (Heavens forbid!) one might advance an unsuspected link between the two.

The meaning of the question might be resolved if the OP accepted one or another answer, but until an answer is accepted I feel it is perfectly legitimate to flag such a question as unclear so the OP can eventually provide additional context or sourcing and thus allow for a correct answer more expansive than “obviously not”.

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    $\begingroup$ I've said it before (many times), and I'll say it again (likely also many times) -- we cannot wait for an answer to determine if a question is on topic. On-topic-ness should be decided solely by the question, as if no answers exist. $\endgroup$
    – tpg2114
    Commented Jul 15, 2017 at 1:38
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    $\begingroup$ I'd argue that in fact, the example question you propose is perfectly clear. The answer is no. You've inadvertently just demonstrated what I mean. $\endgroup$
    – auden
    Commented Jul 15, 2017 at 12:33
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    $\begingroup$ @heather The statement is clear but the meaning isn't. Plus, there might be a connection, but as phrased the question would be rejected out of hand. Well... we'll have to agree to disagree. Thankfully the review process is collective and no person as absolute power - at least if one does s/he isn't acting omnipotent. $\endgroup$ Commented Jul 15, 2017 at 14:21
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    $\begingroup$ @ZeroTheHero the meaning seems pretty clear to me - it's asking about connections between pink hippopotami and blue skies. The answer is there is no connection. The question is weird, ill-informed - not unclear. $\endgroup$
    – auden
    Commented Jul 15, 2017 at 14:23
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    $\begingroup$ Definitely, wrong example: try with another one. $\endgroup$ Commented Jul 16, 2017 at 7:21

1. The votes can be justified

Questions which have a simple, obvious Yes/No answer are generally disapproved of. See for example the answers to Self Study Students: Confirmation Type Questions and Can we stop closing questions as "unclear what you are asking" for OPs above certain reputation?

The user who provided the only answer to Increasing The Momentum Of A Photon also commented that the question is trivial :

I think it is a trivial question to answer. The OP is simply asking can we increase the momentum without increasing energy. The answer would be simply no. – Dvij Jun 30 at 4:58

What is unclear about this question (in my opinion) is why the asker thinks the answer is more complicated than that. The onus is on the asker to show what his/her difficulty is. Without such context or explanation, his/her difficulty cannot be addressed, it can only be guessed at. In that sense I think the question is unclear even after the edit (v2) and the close votes are justified.

Others may disagree. It is inherent in the nature of reviewing that different reviewers may come to a different conclusion about the same question. Unless there is a policy which specifies what makes a question unclear, the reviewer must apply his/her own individual judgement, rather than try to second-guess others who have not yet voted, or vote with the majority who have already voted. Those who disagree are able to vote to reopen, and have done so.

Clearly you disagree with the votes to close the question as unclear. This is a difference of opinion, not a misuse of the close reason.

The OP has not commented upon nor approved the only answer, so we do not know if this answer has addressed the issue which the OP was asking about.

2. "Not unclear if there is an answer" is not site policy

I agree with @ACuriousMind that the presence of a valid answer does not determine that the question is not unclear. Whether or not a question is unclear (or a duplicate, or too broad, or primarily opinion based, or not mainstream physics, or an engineering question etc) is determined collectively by those who have the rep to review questions, not by those who have the rep to post answers.

Reviewers must be free to exercise their own judgement, independently and impartially, within the guidance provided by site or network policy. If (as it appears to me) you think some policy is being abused, it is up to you make your case by identifying that policy. Otherwise, you are merely expressing an opinion.

If the posting of a valid answer makes unclear what you are asking invalid as a reason for closing, why doesn't it do the same for too broad or homework-like or engineering? Or indeed for all closure reasons? Such a policy would give those who answer the question the ability to over-ride the decisions of those who review the question. It would make the process of reviewing pointless.

The explanatory text for this close reason does not state that the question cannot be answered, but that it is difficult to interpret :

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking....

As was the case with the question Reminder that Book Recommendations are on topic, the community continues to close questions contrary to your interpretation of site policy after your "reminder" was posted. For example :

What "things" don't change?
Can you use sun light to heat an objects surface to hotter than the surface of the Sun?
Resistance of filament
Why does the big bang not violate Heisenberg's uncertainty principle?
Is a gravity train really possible? If yes, can it be used as a seemingly endless source of energy?
Are fundamental particles (Electron,Proton & Neutrons) compressible?

Were the reviewers who voted to close these questions abusing the policy "not unclear if there's an answer"? Or is there no such policy?

  • $\begingroup$ Why the down-votes? My answer is compatible with the upvoted comment by @ACuriousMind. $\endgroup$ Commented Jul 5, 2017 at 12:25
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    $\begingroup$ Note that comments can't be downvoted --- this is a disadvantage of comments. $\endgroup$
    – rob Mod
    Commented Jul 5, 2017 at 17:40
  • $\begingroup$ Also note that downvotes simply mean disagreement on Meta, but you might already know that. $\endgroup$
    – jpmc26
    Commented Jul 7, 2017 at 18:59

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