These seem to be accepted by the community

(there may be more, I'll do a more careful search if necessary)

Yet five people decided to quickly block anyone else from answering Would it have been possible to send a radio signal towards ʻOumuamua? +2, 1 answer pending

One of those blocked was almost me; in mid-answer. It will be a good answer (I think); helpful to the OP and perhaps others.

I will include the distance to the asteroid from Earth from 2017 to the present, point out that a spacecraft in the Kuiper belt can certainly receive signals from us, though they are slow and it has to know the direction, time and frequency range to check.

But without four more re-open votes, nobody else will be able to post a better answer.

Must further answers be blocked here? Is this really off-topic? If so, why, while the three mentioned above are simultaneously fine?

pre-emptive answer-blocking


2 Answers 2


Astronomy.SE Help gives no guidance as to whether SETI questions are on-topic or not. SETI is at least a respectable pursuit these days, although it was not always so.

The question that you are referring to seemed to be a bit "UFOish", which is why I voted to close it. Maybe there is a case for re-opening it. However, there is a big difference between conducting a systematic (and laborious) search for extra-terrestrial civilisations, where the chance of success still seems to be vanishingly small, and getting excited about some random asteroid that happens to pass through our solar system. Just because it appears to be highly elliptical in shape is not sufficient reason to assume that it must be an alien spacecraft.

Obviously, astronomers would love to get their hands on some interstellar rocks, hence the interest in possible meteor showers emanating from Oumuamua, but I wonder if the SETI crowd have pinged Oumuamua to see if they might get a reply? I very much doubt it.

I'm sorry that you had the rug pulled from under your feet. It never occurred to me that someone would attempt a serious answer. Voting to re-open.

  • 2
    $\begingroup$ Thank you for your thoughtful, speedy and helpful answer! It turns out the rug wasn't actually pulled, and I'm confused by this. On low question-rate sites like this my feeling is always that unless a question really needs to be closed because it is hopelessly off-topic or can't be answered because only opinions can answer it, there's no benefit to closure. It's a thoughtful, helpful community and usually things can be worked out in comments and if necessary the answer edited and improved. Insta-closure might be necessary in high question rate sites but probably not in the slower Q communities $\endgroup$
    – uhoh
    Commented Sep 29, 2020 at 5:01

Thanks for an important meta-question @uhoh, and especially for your comment on (@)Mick's answer. While your "insta-closure" label is a bit inflammatory, your comment is really helpful in understanding your position. I do get the point you're making. I also acknowledge your unstinting efforts at making newcomers to our site feel welcome.

I cut my SE teeth on [ELU.SE], which has very high traffic & an almost unmanageable number of genuinely bad questions - 150+ questions in the Close review queue isn't unusual. But you're quite right that the low traffic on [Astronomy.SE] doesn't warrant the same vigilance, and [note to myself ;-) ] we can therefore be more relaxed in assessing "borderline off-topic" questions.

We should remind ourselves of this site's purpose, which is set out in the opening paragraph of Astronomy [Tour] page:

Astronomy Stack Exchange is a question and answer site for astronomers and astrophysicists. It's built and run by you as part of the Stack Exchange network of Q&A sites. With your help, we're working together to build a library of detailed answers to every question about astronomy.

The last 10 words are the key, and should guide us every time we review a question. Is the question about astronomy? If not, it should be closed. If it is about astronomy (as defined in the On Topic page in the Help Centre), has it been asked before (close as a duplicate), and if not, is the question clear enough to enable our site's community to deliver an authoritative answer? If the question is unclear, or needs further detail, or is too complex (eg too many questions & needs more focus), we can either edit it ourselves if the OP's intention is clear, or we should post a comment drawing the OP's attention to what needs editing. And we can VTC in case the OP fails to edit the question appropriately.

The grey zone is typically where there's something in the question that causes some in our community to think it's either not about astronomy, or it's pursuing an unscientific path of enquiry. There is certainly a knee-jerk reaction to anything that seems like it's about astrology (mention the word "zodiac" at your peril!) or weird hypothetical (like "would the Moon still cause tides if it was made of cheese?", or "What do you think of my theory that dark matter is caused by ...").

The question you've linked to is one of these "grey zone" questions, as it refers to the idea that ʻOumuamua might be an alien spacecraft. This is no doubt what prompted the VTCs. Nonetheless, your answer to that question demonstrates that even if the question itself seems to veer towards being off-topic, a good answer can steer it back towards astronomy.

Referring back to my earlier quote from the Tour page: yes, this question does enable us to fulfil our site's purpose. Anyone searching our site for questions about ʻOumuamua will find a useful answer on how radio signals might be detected or received. Our library is improved as a result.

TL;DR: As a relatively young Stack Exchange site with a low volume of questions, we can afford to be a bit forgiving if a question strays into the grey zone, provided we can see the opportunity to steer it back via an authoritative answer using mainstream science.

  • 1
    $\begingroup$ Thank you for your thoughtful answer! I don't think that "ʻOumuamua might be an alien spacecraft." is even in a grey zone; it in fact might be, and astronomical evaluation and discussion is the only way to address that. $\endgroup$
    – uhoh
    Commented Oct 18, 2020 at 5:07
  • 1
    $\begingroup$ Thank you also for expanding on how low question rate sites can handle questions in a more thoughtful and genlter way than high-Q sites. $\endgroup$
    – uhoh
    Commented Oct 18, 2020 at 5:09

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