Wikipedia:Featured article candidates/Earth-grazing meteoroid of 13 October 1990/archive1

@Curly Turkey: I agree with your copyedits and all your comments. I've redlinked the meteoroid above Japan and cited the piece about the all-sky fisheye objective (it was simply in the same reference as the sentence before it). The 1972 Great Daylight Fireball was also recorded on camera, so it's the former. How do you suggest we rephrase it? As for the deceleration, the source lists all 0 m/s², except for one data point at the meteoroid's perigee, where it lists 1 m/s². I find it hard to believe that it would be actually zero all that time and so suddenly jump to 1 and back again, so it must have something to do with the numerical accuracy of the calculation (but there is no comment on this in the source). So, "practically not decelerated" would mean "no deceleration to within the accuracy of the calculation". --JorisvS (talk) 16:25, 22 April 2015 (UTC)[reply]

How about something like "detected no deceleration"? For the two cameras bit, I can't think of an elegant way to handle it at the moment—ideally, it should be reworded, but I don't think it's a parituclarly important ambiguity. Curly Turkey ¡gobble! 02:04, 23 April 2015 (UTC)[reply]

It is about a computer simulation, so I don't know how appropriate 'detected' really would be. What about using basically what I already said above, i.e. "who found no deceleration along the meteoroid's track to within the accuracy of the calculation, except for a very short time near perigee, when it was approximately 1 m/s²."? --JorisvS (talk) 07:29, 23 April 2015 (UTC)[reply]

I'm fine with this. Curly Turkey ¡gobble! 11:25, 25 April 2015 (UTC)[reply]

As for that bit of ambiguity, what about just removing "by cameras", because "recorded" already more or less implies as much, so "first recorded by cameras from two distant positions"? --JorisvS (talk) 07:36, 23 April 2015 (UTC)[reply]

I think the version without "by cameras" is good. Another possibility might be "...first recorded by cameras that were located at two distant positions" (as opposite to "...first recorded by cameras, which were located at two distant positions"), but it is longer. Jan Kameníček (talk) 11:42, 24 April 2015 (UTC)[reply]

The ambiguity doesn't come from the cameras, it's about what was first: "being recorded" or "being recorded from two locations". The wording could be parsed as the former. Curly Turkey ¡gobble! 11:25, 25 April 2015 (UTC)[reply]

It seems to me that "first recorded from two distant positions" has no ambiguity. I think it cannot be understood as "first recorded", but I am not a native speaker. Jan Kameníček (talk) 21:52, 26 April 2015 (UTC)[reply]

I'm not going to withhold support over it, but it is indeed ambiguous as I've explained, which is why I had to ask for an explanation—because it wasn't clear to me which reading was correct. Curly Turkey ¡gobble! 22:49, 26 April 2015 (UTC)[reply]

I think that technically, "first recorded from two distant positions" can only mean the being the first from two different locations, whereas being the first recorded and incidentally also from two different locations would best have to be rephrased someway, but at least should have an additional comma, "first recorded, from two distant positions". However, because such commas are not sufficiently consistently used, I understand why it got you wondering (and, by extension, other readers). It currently reads "[it] was the second one scientifically observed, after the 1972 Great Daylight Fireball, and the first recorded by cameras from two distant positions"; couldn't we, because the 1972 GDF was also recorded, rephrase this to "[it] was the second one recorded, after the 1972 Great Daylight Fireball, and the first one from two distant positions"? It would eliminate all potential ambiguity/confusion. Or is something more meant by "scientifically observed"? --JorisvS (talk) 09:33, 27 April 2015 (UTC)[reply]

I think that wording would be fine. Curly Turkey ¡gobble! 11:45, 27 April 2015 (UTC)[reply]

Okay, I've changed it, though I still would like to hear @Jan.Kamenicek:'s input. --JorisvS (talk) 10:07, 28 April 2015 (UTC)[reply]

I do not think it is good to replace "second scientifically observed" for "second recorded", because there are some records about Earth-grazing meteoroids preceding the 1972 and 1990 events, such as the 1860 Great Meteor. That is probably why the sources such as Borovička & Ceplecha talk about "scientifically observed" events. --Jan Kameníček (talk) 18:00, 28 April 2015 (UTC)[reply]

@Jan.Kamenicek: I would rather think it the other way around, then. In the 19th century there were no cameras, so an event like this back then could not have been recorded, at least in its intended meaning, i.e. #2 and the closely related meanings. However, there were already astronomers who could make scientific observations. I'm open to finding a more precise synonym. --JorisvS (talk) 18:52, 28 April 2015 (UTC)[reply]

I cannot find a synonym that would express the same as "scientifically observed", which is in my opinion most precise, but I feel that the word "recorded" (whose first meaning is "To make a record of information") brings more disambiguity than there was before, if it is is used also for the first part of the sentence. Therefore I suggest to keep the original version "this was the second one scientifically observed, ..., and the first recorded by cameras from two distant positions". The words "by cameras" can be omitted (though not necessarily) because here it is clear that meaning number two is used ("To make an audio or video recording of"), because meaning number one would not make sense (it cannot be second scientifically observed and first with recorded information at the same time). I agree with the opinion of JorisvS that the meaning "first recorded and incidentally also from two different locations" cannot be assumed from the original wording. Jan Kameníček (talk) 19:21, 28 April 2015 (UTC)[reply]

You can assert it all you want—I did, in fact, read it both ways. Curly Turkey ¡gobble! 19:28, 28 April 2015 (UTC)[reply]

Omitting "by cameras" brings the words "recorded" and "from to distant positions" close to each other and then they seem more to belong together inseparably. Jan Kameníček (talk) 20:12, 28 April 2015 (UTC)[reply]

Technically it can only be read one way, but many readers may not read it quite that technically, which is why I prefer to address it anyway. As far as I can tell, both the 1972 and 1990 meteoroids have been recorded on camera and the only significant difference in this respect is that the 1990 meteoroid has been recorded on cameras from two quite distinct positions. Now, "scientifically observed" is less precise than "recorded", but even "recorded" is ambiguous without a qualifier. What about using "recorded on camera" instead? --JorisvS (talk) 10:10, 29 April 2015 (UTC)[reply]

OK, I understand. And what about writing both, i. e. "...the second one scientifically observed and recorded on camera (after the 1972 Great Daylight Fireball) and the first one recorded from two distant positions". I think it is quite important to point out that it was observed by scientific equipment, unlike many other notable meteors that were only incidentaly recorded e. g. on a tourist camera and then these amateur pictures were given to scientists (such as the Morávka meteorite, though it was not an Earth-grazer). Here the wording "first one recorded from 2 positions" should not be ambiguous thanks to the previous part of the sentence. --Jan Kameníček (talk) 12:24, 29 April 2015 (UTC)[reply]

Well, in that case we could rather specify the kind of camera being meant, instead of writing the vague phrase "scientifically observed". --JorisvS (talk) 15:49, 29 April 2015 (UTC)[reply]

I can add the type of objective that all the cameras of the European Fireball Network use, but this can probably come later in the text. I am not sure how this fact could be used instead of pointing out that the 1972 and 1990 Earth-grazers were the only two that received direct attention of scientists until that time. But if you still do not agree with writing that, I will not insist on it anymore. It is not so important to spend so much time discussing it. Jan Kameníček (talk) 20:25, 30 April 2015 (UTC)[reply]

I didn't mean type of camera like that. Just as in "camera used for professional astronomy" or something as opposed to one used by the general populace. It would make it something like "this was the second one recorded by astronomical cameras, after the 1972 Great Daylight Fireball, and the first one from two distant positions". --JorisvS (talk) 21:06, 30 April 2015 (UTC)[reply]

Now I see... The 1972 fireball was not observed by a typical camera, it was done using infrared radiometer tracking onboard a satellite. So maybe we could formulate it like this: "...the second one recorded using scientific astronomical instruments (after the 1972 Great Daylight Fireball) and the first one from two distant positions,...". --Jan Kameníček (talk) 21:19, 2 May 2015 (UTC)[reply]

Didn't know that! Thank you for finding that! Yes, that works. --JorisvS (talk) 08:29, 3 May 2015 (UTC)[reply]

• Support—my comments were all pretty hairsplitting, and they've all been dealt with. Curly Turkey ¡gobble! 10:55, 28 April 2015 (UTC)[reply]

Comments from Mike Christie

Support. I've read through twice and made a couple of very minor copyedits. Just one minor issue that doesn't affect my support.

• "It took 78 seconds": I think this means that Kristensen was able to detect the meteor for 78 seconds. If so I'd suggested "It lasted 78 seconds".

• Thank you. I changed the wording. Jan Kameníček (talk) 18:26, 28 April 2015 (UTC)[reply]

A concise and well-written article. Mike Christie (talk - contribs - library) 10:35, 27 April 2015 (UTC)[reply]

Comments from Sarastro

Leaning support: This looks good, with one qualification. Long scientific articles tend to baffle the general reader and cannot be simplified without compromising their brevity and comprehensiveness. Here, we have an opportunity to take something which is intrinsically interesting and make it accessible for the general reader and not have to worry about it being too long. I'm inclined to support this, but would like to see if we can improve it on this score first. Additionally, an article as short as this should be almost perfect as an FA as there is greater opportunity for readers to focus on any issues! Sarastro1 (talk) 19:25, 13 May 2015 (UTC)[reply]

• "The calculations were published by Czech astromers Pavel Spurný, Zdeněk Ceplecha, and Jiří Borovička from Ondřejov Observatory,[5][1][3]..." These refs should be in numerical order.

  I am not sure. I put them in this order on purpuse: it is the order in which they were published. Jan Kameníček (talk) 00:12, 17 May 2015 (UTC)[reply]

  I'm pretty sure this is in the MoS somewhere, but of course I can't find it at the moment. In any case, it's standard practice at FA level. Sarastro1 (talk) 10:14, 17 May 2015 (UTC)[reply]

  Pardon me for jumping in with a digression, but I think (I could be wrong) that this is not in the MoS because there are situations where some editors prefer not to do it. I don't have strong feelings about this myself, but the argument is that a main reference should go first in the footnote list, regardless of numerical sequence, and footnotes that only support minor parts of the text should follow. Mike Christie (talk - contribs - library) 11:06, 17 May 2015 (UTC)[reply]

  I can see the merits of that. My main issues would be that a) it looks like an error and b) someone will eventually "fix" it anyway. I wonder if there is a compromise? I don't think I've ever seen a FA that doesn't follow the numerical order. That said, although my preference is for numerical order, I don't care so much that it would affect my support! Sarastro1 (talk) 13:14, 17 May 2015 (UTC)[reply]

  What about not defining the references inline, but in the reference list, and then order them so that they appear in numerical order? --JorisvS (talk) 11:31, 18 May 2015 (UTC)[reply]

  Sounds fine to me. Sarastro1 (talk) 20:10, 26 May 2015 (UTC)[reply]

• As this is quite a short article, I wonder if we could provide some slight context for the non-specialist. For example, the mass was 44kg; is this big? How does it compare to other meteoroids? (Someone clicking on this article might wonder if it was potentially one that could wipe out humanity, and if they don't know how this compares, they might still think it could have done after reading it!) How do the magnitudes compare with, for example, stars or meteors? Can we give context to the heights? Most readers will probably not know the height of the atmosphere off hand.

These are good points we'll have to look into. --JorisvS (talk) 09:44, 22 May 2015 (UTC)[reply]

I agree, good points. I added some apparent magnitude comparison and a note about the Kármán line. As for the mass, it had already been compared to the mass of the 1972 Great Daylight Fireball, described as "a thousand times more massive", see the section Similar events. Is it OK like this? Jan Kameníček (talk) 22:08, 27 May 2015 (UTC)[reply]

Something about what would have happened if it had hit the surface. Maybe a comparison with the Chelyabinsk meteor. --JorisvS (talk) 08:36, 28 May 2015 (UTC)[reply]

I do not know. We can assume that the body would not survive the flight through the atmosphere, but there is no source that would say it directly. We can also look for a source saying which bodies survive and which not, but all sources I saw mentioned only the size and not the mass (in fact none of these two is sufficient, because too many things play a role: mass, size, porosity, shape, speed, angle...). The only thing to be done is to calculate the diameter, knowing the mass 44 kg and assuming the average density of type I fireballs to be 3.7 g/cm3. This gives the diameter of about 28 cm (if it was a ball and if I calculated it correctly), and thus we may come to the conclusion that it was too small and had no chance to survive and hit the surface of the Earth. But it is a sort of original research. Jan Kameníček (talk) 21:06, 29 May 2015 (UTC)[reply]

I was thinking about it again and finally I wrote something based on the website of the Australian Museum, which speculates about sizes of meteoroids that have a chance to reach the surface. Although they do not write about the mass (only about the sizes), it is quite clear from the text that "our" meteoroid would mean no danger. Jan Kameníček (talk) 18:44, 30 May 2015 (UTC)[reply]

• I also wonder, given the short length, if we could be kinder to the reader, and maybe explain terms like "a typical meteoritic fusion crust" and "perigee" (such as we have done for aphelion) without needing to follow links?

Done Explained "perigee". --JorisvS (talk) 09:44, 22 May 2015 (UTC)[reply]

I think there is more that would stand explanation, but this is not essential. But it would help the general reader. Sarastro1 (talk) 20:10, 26 May 2015 (UTC)[reply]

I meant to say only that I have done it for "perigee", not that I disagree with the other. That one simply needs a little more work on my part (or from someone else) to get right. --JorisvS (talk) 20:44, 26 May 2015 (UTC)[reply]

I explained it in the text. Is it OK now? Jan Kameníček (talk) 21:50, 26 May 2015 (UTC)[reply]

I think that that is a rather an approach to making it understandable to absolute laymen, but physically inaccurate. Despite that the point of it is to explain it to laymen, it should still be physically accurate. For one, I think the crust forms because it melts and solidifies again, not because it "burns" (i.e. a reaction with oxygen). I've given it a try. --JorisvS (talk) 08:36, 28 May 2015 (UTC)[reply]

Well, there had already been written that the crust was formed by melting and solidifying before I added the lay explanation. That is why I thought that it is demanded to simplify it even more. Now, after JorisvS rewrote the text, there is twice the same thing in one sentence. So, if you think that the melting-solidifying explanation is OK and does not need more simplification, I suggest that we return the original version (i. e. the version before this edit). Jan Kameníček (talk) 18:43, 29 May 2015 (UTC)[reply]

Right. What about now, after my two edit to it? Also, we should now check the two sources at the end to see if they're in the correct place. --JorisvS (talk) 13:19, 30 May 2015 (UTC)[reply]

That sounds good, thanks. I removed one of the sources, because it was a source that I had added together with the oversimplified explanation, which is now removed again. Jan Kameníček (talk) 17:53, 30 May 2015 (UTC)[reply]

• Another example: "It recorded the bolide's trajectory over approximately 110°, starting 51° above the southern horizon": These numbers would be meaningless to the general reader; they probably just want to know how much of the sky it crossed, so can we explain that in words?

Not sure Do you have a suggestion how we could do that? --JorisvS (talk) 09:44, 22 May 2015 (UTC)[reply]

@Sarastro1: Supposing that the full arc from the southern horizon to the northern horizon is 180° and the body crossed 110°, we can say that it was visible through 60 % of the sky. Is this what you mean? Jan Kameníček (talk) 20:32, 25 May 2015 (UTC)[reply]

Yup, that would work for me. Sarastro1 (talk) 20:10, 26 May 2015 (UTC)[reply]

• "According to their report, the event started at 3h 27m 16s ± 3s": Similarly, this will baffle the general reader. Why not give it as a simple time?

  I am not sure if I understand. What do you mean by "simple time"? Something like "half past three"? Jan Kameníček (talk) 00:12, 17 May 2015 (UTC)[reply]

  I think he means as "3:27:16±3"—"3h 27m 16s ± 3s" is an unusual way to give a clock time in English. Curly Turkey ¡gobble! 04:47, 17 May 2015 (UTC)[reply]

  Couldn't have put it better myself! Sarastro1 (talk) 10:14, 17 May 2015 (UTC)[reply]

  Done Though using 03:27:16±3, because that looks even better. I am wondering about the "16±3", because it is typical to have spaces before and after a ±, but the space may make it unclear what exactly the uncertainty refers to. --JorisvS (talk) 09:44, 22 May 2015 (UTC)[reply]

• "also detected a radio reflection": Another one that we could explain better?

Done It should, I thought it meant that the bolide was detected using radar, but the source talks about a "

pen recorder". I have rephrased it to use these terms to clarify it, though unfortunately there is no article for pen recorder (yet). --JorisvS (talk) 09:44, 22 May 2015 (UTC)[reply

]

The article is at

pen recorder. --Mirokado (talk) 21:42, 22 May 2015 (UTC)[reply

]

Thanks! --JorisvS (talk) 08:22, 23 May 2015 (UTC)[reply]

• Lots of sentences begin with "The" or "It". Could we introduce a little more variety?

Not sure I may have fixed some of it, but if you like more, I'd like to hear a suggestion. --JorisvS (talk) 09:44, 22 May 2015 (UTC)[reply]

I'll take another look at this when everything else is done. Ping me if I don't get back to you. Sarastro1 (talk) 20:10, 26 May 2015 (UTC)[reply]

• "its angular velocity was so low that it got below the resolution of the instrument": I would recommend a more elegant word than "got"; maybe "fell"?

Done Rephrased to avoid a verb altogether. --JorisvS (talk) 09:44, 22 May 2015 (UTC)[reply]

• Why do we spell out grams, when all other units are abbreviations? (Maybe I'm missing something)

Done --JorisvS (talk) 09:44, 22 May 2015 (UTC)[reply]

• "The program gave an apparent magnitude of −5.7 at the moment when it was seen by one of the cameras and −6.3 at perigee. It did not differ significantly from its absolute magnitude at this point. Then, [The]the bolide [subsequentl] got dimmer [dimmed], with an apparent magnitude of −5.4 at the moment when it was last seen by the cameras and a final calculated value of +6.0 at a height of 257 km." Could be improved to remove redundancy and repetition? Sarastro1 (talk) 19:25, 13 May 2015 (UTC)[reply]

Done Certainly. I have kept the phrasing of the two original items of "at the moment when" consistent, using simply "when". The best professional style is to use the same phrasing consistently if that phrasing is correct. --JorisvS (talk) 09:44, 22 May 2015 (UTC)[reply]

@Sarastro1: Thank you very much for the points. I do apologize for being very busy this week, but I will try to address them as soon as possible. Jan Kameníček (talk) 00:12, 17 May 2015 (UTC)[reply]

• No problem. Sarastro1 (talk) 10:14, 17 May 2015 (UTC)[reply]

Comment: I'm more or less happy with this, but I would still suggest looking for ways to simplify for non-specialists where possible. Let me know when everything is done and I'll take another look. Sarastro1 (talk) 20:10, 26 May 2015 (UTC)[reply]

@Sarastro1: I tried to address the last remaining points, so I think you may have a look if it is OK now. And many thanks to JorisvS, who addressed the previous points! Jan Kameníček (talk) 22:18, 27 May 2015 (UTC)[reply]

@Sarastro1: Should we consider your comments addressed at this point or are you wanting to run through it again? --Laser brain (talk) 00:39, 31 May 2015 (UTC)[reply]

I've had a last look, and I'm more than happy. Thanks to the nominator for their patience. Nice work, and I've switched to full support. Sarastro1 (talk) 08:59, 31 May 2015 (UTC)[reply]

Comment - please don't use {{Done}} and similar graphical templates (see FAC-instructions), they can cause problems with FAC-page processing (I took the liberty and changed them to bold text). Thank you. GermanJoe (talk) 12:03, 24 May 2015 (UTC)[reply]

• "1972 Great Daylight Fireball" is linked twice but not at the first instance. Also, how bright was at its blightest compared to a more common object say Venus or Jupiter?
  Nergaal (talk) 17:08, 26 May 2015 (UTC)[reply
  ]

I added a comparison to the planet Uranus. As for the 1972 Fireball, it is mentioned 3 time in the text and linked at the first instance (in the lead) and then at the third instance (in the last section). Jan Kameníček (talk) 22:15, 27 May 2015 (UTC)[reply]

I already fixed that. Sorry for not noting it here. --JorisvS (talk) 07:57, 28 May 2015 (UTC)[reply]

We should also have a comparison for its brightest (lowest app. mag.). I've added a rough comparison with Venus. --JorisvS (talk) 08:15, 28 May 2015 (UTC)[reply]

We have "The Červená hora image was especially valuable.", but wasn't this a series of images or something? After all, it recorded a trajectory and had a rotating shutter. --JorisvS (talk) 08:22, 28 May 2015 (UTC)[reply]

Spot check by Cas Liber

Source #1 checked (10 items) - text faithful to source and not paraphrased.
Source #7 checked - text faithful to source (item/word only)
Source #8 checked - text faithful to source (item/word only)
Source #6 checked (5 items) - I can't see where it says in the source it is a type I bolide. Other 4 sentences ok.

@Casliber: Source corrected. Thanks for heads up! Do I understand it correctly that the other sources mentioned above are OK? Jan Kameníček (talk) 18:47, 29 May 2015 (UTC)[reply]

Ok - all good then. Cas Liber (talk · contribs) 22:09, 29 May 2015 (UTC)[reply]

• Closing note: This
  WP:FAC/ar, and leave the {{featured article candidates}} template in place on the talk page until the bot goes through. Ian Rose (talk) 09:47, 31 May 2015 (UTC)[reply
  ]