A comment on the question How moon is visible during sun is still shining, simple explanation please! says in part:

I appreciate your attempt to meet the OP's request for a simple explanation, but you seem to have overlooked our Help Page description: "The purpose of this site is to provide expert level answers"

I don't see any way around it; this strict interpretation seems to suggest that a question asking for simple explanation should be closed as off-topic.

To me that seems over the top.

  • I don't think we should turn away users who need answers written below "exptert level"
  • Until today, I've never seen any suggestion that answers written at a more accessible level to the general public were so undesireable that even when explicitly requested, we take measures to direct traffic away from them.

So I'd like to ask the following:

Question: Are all questions asking for simple explanations really off-topic?

Shall we start closing them quickly? If so, should we also start marking all non-expert level answers for deletion because they defy the "purpose of the site"? In that case, what would be the impact on the site's growth?

Would a collection of good answers that include some answers written at a basic level be somehow less valuable?

The beginning of https://astronomy.stackexchange.com/help/on-topic

What topics can I ask about here?

Astronomy Stack Exchange is a Question and Answer site about astronomy and astronomy related topics; the study of objects and matter outside the Earth's atmosphere and of their physical and chemical properties

The purpose of this site is to provide expert level answers to questions on:

  • Setting up, using and maintaining your astronomy related equipment
  • Astronomical observations, for all celestial objects across the entire spectral range.
  • Astrophysics and Cosmology
  • Planetary Science and Celestial mechanics
  • Data returned by space missions such as probes, rovers and satellites
  • What type of equipment will allow you to see a certain entity
  • History of Astronomy

2 Answers 2


TL;DR: My assessment is that a request for a simple explanation does not conflict with the site's purpose of providing "expert-level answers", so such a request does not make the question off-topic.

I posted the comment on the linked question regarding on-topic usage, so let me try a response.

Question: Are all questions asking for simple explanations really off-topic?

I think this is an important question for Meta, so thanks for asking it. It's important because it draws our attention to the core purpose of our own site, as well as the broader intention of the Stack Exchange network, the way SE operates, and how we should approach community moderation on this site.

Questions versus answers

I think there are two distinct issues involved here: the site's purpose in providing answers, and our filters as community moderators for what are acceptable questions (for which being on-topic is only one of many criteria for closure).

Stack Exchange quite deliberately emphasises the difference between questions and answers. For example, a user only gets half the points for an upvoted question as an upvoted answer; the system makes closing someone's question much easier than deleting someone's answer; and there's a penalty for downvoting answers, whereas there's no penalty for downvoting questions. Why is there this difference? The best answer is given in this blog by SE's co-founder: Optimizing For Pearls, Not Sand.

I've noticed that, at least on the five Stack Exchange sites I'm active on, a surprising number of users are unaware of Jeff Atwood's explanation regarding Stack Exchange's different approach to questions versus answers, and I've seen that this sometimes leads to confusion and errors in community moderation. For example, I've previously posted on Astronomy Meta that some users tend to be too quick to flag/vote an on-topic question for closure, when they should have either improved the question by editing it, or simply downvoted it as not useful.

What does expert-level mean?

I interpret "expert-level" to mean that the content is correct, accurate, and contains nothing that experts in that field would regard as plain wrong. If, instead, we took the Help Page's dictum for "expert-level answers" literally, it would raise the bar to the equivalent of [Physics.se]. This would exclude active contributors like me from answering any questions here, as I have no formal degree or professional experience in astronomy or related fields that would qualify me as an "expert". Yet I've contributed 24 answers here, with an average of 3 votes per answer and no answer with a negative score, which suggests that my contributions have been both useful and welcomed. I get no sense that this site really wants to bar users like me from answering questions.

Is "simple explanation" compatible with "expert-level?

I genuinely think this falls in the "interpretation and flexibility" category – in other words, it will depend very much on the nature of the thing being asked about, the degree to which a "simple explanation" can be given from an expert perspective, and the degree to which the asker is insisting on constraining potential answers in a way that doesn't benefit the site overall.

An example might help. If I ask "how is the stress-energy tensor derived?" but I add that I want the answer explained in simple high-school terms, I would regard this as on-topic but potentially hard to answer. Yet if someone could provide an answer using high-school physics, analogy to other systems or concepts, and lots of handwaving (i.e. giving an expert response made understandable), I would argue that the answer has achieved our site's purpose.

The question linked to in this Meta post asked for an answer "in simple words without using astronomy terminologies". @uhoh provided a good answer that met these requirements, and I see no conflict with the site purpose, as the author used their expert knowledge to craft an answer that was correct, accurate and useful.

However, it turns out that a similar question had already been asked, and the community of users voted that the other question provided an adequate answer.

There are three answers that were posted before the duplicate question was closed, and all three have multiple upvotes indicating users found them useful. Since duplicate questions are retained on the site, the three answers now provide an additional resource and benefit for future visitors. In my view, they are helping to achieve the site's purpose.

Of course, if the question had been closed as a duplicate before those three contributors had been able to post an answer, and someone believed the answers to the older question weren't adequate, a simple solution would be for that person to post their "simple explanation" answer at the older question, perhaps with a preface that it provides a more direct and less technical response that the other answers are lacking. This, too, would (in my view) support our site's purpose and add to the value of our Astronomy library.


Are all questions asking for simple explanations really off-topic?

Of course not. This site has generally been quite welcoming to questions asking for simple explanations.

Shall we start closing them quickly?


If so, should we also start marking all non-expert level answers for deletion because they defy the "purpose of the site"?

Absolutely not. For several reasons. 1) it defies the idea of being welcoming, 2) some people need time to improve, 3) a mix of different level answers is healthy because it provides future readers with some variety and many may find basic level answers the most helpful.

In that case, what would be the impact on the site's growth?

It would be bad.

Rather than writing tomes about how to interpret the sentence:

The purpose of this site is to provide expert level answers to questions on:

...why not modify it slightly to accommodate the reality that a Stack Exchange site has more than a purely singular purpose.

How about some of these modifiers which embrace how the site operates in reality and what it is we are trying to do here?

  1. The main (or primary) purpose of this site is to provide...
  2. ...is to provide helpful, authoritative and community-reviewed answers to questions on:
  3. The purpose of this site is to provide a positive environment where a community of experts and non-experts can work together to build a repository of...

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