Check for proper usage of "equinox" vs. "epoch" when discussing the coordinates of astronomical objects. Equinox refers to the precession of the coordinate system used. Epoch refers to the timing of an event such as an observation.
This page is within the scope of WikiProject Astronomy, which collaborates on articles related to
Astronomy on Wikipedia.AstronomyWikipedia:WikiProject AstronomyTemplate:WikiProject AstronomyAstronomy articles
Context: Right now, the use of imperial/U.S. customary units are inconsistent among articles (for example,
Sun,
Mars,
Earth and has imperial conversions, but
Pluto,
Mercury (planet) and
Ceres (dwarf planet) don't). For articles that do use imperial/U.S. customary units, they also have SI conversions and often uses {{convert}} template.
MOS:UNITS applies, with the alternative being units conventional to astronomy.
Praemonitus (
talk) 06:07, 20 January 2024 (UTC)reply
If so then all U.S. customary units be removed from these articles.
CactiStaccingCrane (
talk) 06:21, 20 January 2024 (UTC)reply
Specifically for science articles (not necessarily for biographies or histories), per
MOS:CONVERSIONS: "...in science-related articles, supplying such conversion is not required unless there is some special reason to do so." To avoid conflict, I'd include the linked policy in the edit notes. Also, I'd hesitate to apply this to the
Earth article.
Praemonitus (
talk) 15:14, 20 January 2024 (UTC)reply
I'm opposed to imperial in general, but we need to keep it when citing values that are given in imperial. The reason is that when we convert to metric, not only may there be rounding errors, but we often change the number of significant digits. And when sources are in imperial, their source data was often in metric and there are already conversion errors involved. Often when we convert back, our figures differ from the original -- that's been a recurring problem with our data. Better to give it in imperial with our metric conversion following in parentheses. Editors will then be aware of the potential for error and try to find the original figures, which should be used instead. When our sources use metric, then we should use metric only, unless our source converted from imperial. In all cases, I think we should attempt to use the original figures, or as close to them as we can find.
— kwami (
talk) 23:52, 20 January 2024 (UTC)reply
We should be using metric units for everything except for material which is specifically US material. Wikipdia is not owned by the US. It is world wide and vast majority of countries now use metric.
Bduke (
talk) 01:11, 21 January 2024 (UTC)reply
Doesn't matter if it's US/NASA. The issue is fidelity to the data. If a US source publishes in metric, we should use metric. If a UK source publishes in imperial, so should we.
— kwami (
talk) 02:27, 21 January 2024 (UTC)reply
No. We are not writing ransom notes with words cut out of other publications. We are giving coherent explanations that are based on reliable sources. To make our articles coherent, we should choose units appropriate to the article, and give the most appropriate unit first. If the unit given in a source is different from what we choose to list first, we can use the convert template in a way that the value copied from the source listed first and the converted value is given first. Since this thread is about infoboxes, it isn't even necessary to give the value from the source in the box at all, so long as it is in the body of the article.
Jc3s5h (
talk) 02:35, 21 January 2024 (UTC)reply
That's what I said, at least for the original data appearing first. Unless we explain that the figure given second is primary, and not just added because someone wanted to plaster imperial all over WP. We don't want someone coming by and deleting the data because that's all they think it is.
— kwami (
talk) 02:39, 21 January 2024 (UTC)reply
{{convert}} has a function of just displaying the output. So it is possible to conserve the original data in some way.
CactiStaccingCrane (
talk) 06:05, 21 January 2024 (UTC)reply
Astronomy data is often published with excessive numbers of digits; far more than is justified by the margin of error. I don't think we need to worry about the accuracy of the conversions. The appearance of excessive accuracy can be misleading in and of itself. We're not an original source for this data, and often we can get by with presenting rounded values.
Praemonitus (
talk) 05:21, 21 January 2024 (UTC)reply
I agree. That's very often the case, and in such cases conversion errors are not an issue. If we have something at ridiculous (and spurious) precision in imperial, then I have no problem simply converting to metric and ignoring the published units. But not infrequently, especially with initial news reports and even beyond that with crude estimates, data is published to very few sigfigs in imperial, and we do introduce a significant error when converting. Say, the impact of an asteroid est. to be 10 miles in diameter -- what do we convert that to? 15 km? 20 km? Usually I see a misleading 16 km, a precision that is not justified by the source.
— kwami (
talk) 07:07, 21 January 2024 (UTC)reply
Again, {{convert}} can be helpful here, by using "round=5" or "round=25" to round to the nearest .5 or .25.
CactiStaccingCrane (
talk) 07:11, 21 January 2024 (UTC)reply
Indeed. I just think that in such cases we need to be clear to the reader that the source data is in imperial, not that we just decided to add a conversion to imperial.
— kwami (
talk) 08:26, 21 January 2024 (UTC)reply
Option 2 seems the right solution to me. If the referenced source is in miles, we should give that value in the infobox for verification, along with a km conversion. If the source was in km, there's no need for miles. A conversion into au or pc might be more useful anyway, depending on context. The sentence about 'science-related articles' in
MOS:CONVERSIONS applies and makes sense to me.
Modest Geniustalk 11:30, 23 January 2024 (UTC)reply
There's a problem though with the wording of Option 2: "Yes for info cited to sources that only use imperial units, otherwise no."
The problem is that sources often include a conversion to metric with spurious precision (e.g. 10mi/16km, where the 10mi is the original number and only an estimate), and the wording of Option 2 means we'd cite only that conversion. That conflicts with the spirit of the MOS warning "Be careful especially when your source has already converted from the units you're now converting back to." That's not just a potential problem with converting back, but with dropping the original number and citing only the converted value. In my example, we shouldn't cite "16 km", but rather something more like "10 mi (10-20 km)" or "10 mi (approx. 15 km)", or even just "10-20 km" or "approx. 15 km".
— kwami (
talk) 12:11, 23 January 2024 (UTC)reply
In those cases, I think it's fine to use the US units in {{convert}} with disp=out, so the original is displayed to editors for verification and the metric is displayed to readers for consistency. So yeah, the wording in the MOS should advise using the original quantity and doing our own conversion. --
Beland (
talk) 01:54, 18 May 2024 (UTC)reply
Okay, added to the MOS.
— kwami (
talk) 02:15, 18 May 2024 (UTC)reply
Perfect. I think that addresses all my concerns. (Sorry, I didn't see the extraneous changes that I typed somehow.)
— kwami (
talk) 02:36, 18 May 2024 (UTC)reply
RFC: Imperial/U.S. customary units in astronomy object infobox
CactiStaccingCrane, this is exactly the same question - if there is no firm consensus from one RFC, why do you think a second one will garner it?
Primefac (
talk) 16:38, 27 February 2024 (UTC)reply
That's because my first RFC is somewhat vague and did not gather enough activity. I do believe that the second RFC will come to a definite consensus.
CactiStaccingCrane (
talk) 16:42, 27 February 2024 (UTC)reply
None of the above. Do not use imperial/US customary units so that they appear in infoboxes. If the source only provides an imperial/US customary unit, or the imperial/US customary unit is better because the SI unit contains unjustified excess significant figures, include the imperial/US customary unit in the body of the article or in a footnote.
Jc3s5h (
talk) 16:39, 27 February 2024 (UTC)reply
Can you explain further what you meant by "excess significant figures"? Can we just trim them out for the sake of brevity?
CactiStaccingCrane (
talk) 16:42, 27 February 2024 (UTC)reply
Sometimes a source will give a value in imperial, such as 93 million miles, which has a few significant figures. The source will give a sloppily-converted value in SI, such as 149.7 Gm in parenthesis. If this value were given in the Wikipedia article it would likely be wrong, because the conversion was calculated from the rounded value, 93 million, rather than the true value. For example if we were talking about the semi-major axis of the Earth's orbit the true value is 92955902 and the value in km, rounded to four digits, would be 149.6 Gm.
Jc3s5h (
talk) 17:07, 27 February 2024 (UTC)reply
This is similar but not identical to the question you asked a month ago, which is confusing. Option 1 is now closest to my preference, but not quite what I would have chosen. More broadly, where are you proposing this rule would go? With what wording? Is there a problem that needs fixing?
In my view, astronomy infoboxes should use a) professional astronomy units (parsecs, solar masses etc.) and b) an SI equivalent if relevant. We don't need to convert everything e.g. listing every star's mass in kilograms isn't helpful to anyone. I wouldn't include an imperial conversion at all, unless the only units available in the references were imperial and the conversion to more appropriate units is shown. I highly doubt that there are many sources that are reliable, only use imperial, and have no alternative better source that gives the value in astronomical or SI units, so that's a very rare edge case.
Modest Geniustalk 17:49, 27 February 2024 (UTC)reply
As a
rule, astronomy infoboxes should contain standard astronomy units, plus SI if relevant (and only if relevant), but no imperial conversion. I'd say that Imperial conversions could be provided in prose, but should
never be primary, and shouldn't go in at all unless the number is of significant interest to non-scientists. I'd add that any rule relying on the specific source adopted - such as Option 2 - is a nonsense because it opens the gate to people just switching the source to something that matches their unit preference. (And yes, people really do do this.) Kahastoktalk 18:24, 27 February 2024 (UTC)reply
We might use only SI in the info box, but imperial in the text if that's what the original (or oldest attested) measures are given in. My worry is the errors that creep in by converting a rough estimate (e.g. 10 miles as a guestimate) into something that looks spuriously precise (16 km).
— kwami (
talk) 23:47, 27 February 2024 (UTC)reply
As for cherry-picking sources, we want the original data, not imperial conversions. Only if the original data is in imperial should we use imperial. Sometimes the oldest source we have has converted SI to imperial, and later SI might be back converted from the imperial. We don't want to copy that. This is mostly a problem with press releases. But once we can access the original data, we should of course go with that.
— kwami (
talk) 23:49, 27 February 2024 (UTC)reply
This is all already considered in
WP:UNITS, and I'm not sure why this topic should be an exception to the standard rules there? Of course if there is an actual quotation (direct or indirect) then you preserve the quote. But if the first person who measured the distance to Mars did it in
smoots, that would not be a good reason for us to use smoots for the purpose. Kahastoktalk 18:21, 28 February 2024 (UTC)reply
If that's the only measure we have, then yes, we should give the results in smoots. I'm not talking about the oldest measurement, but about the original units of the measurement we use.
— kwami (
talk) 18:40, 28 February 2024 (UTC)reply
My view on each of these proposals:
Option 1: Easily the best as there is realistically no context in astronomy in which imperial/USC is preferred over SI (or other scientific units, including occasionally some pre-SI metric relics). My main objection is to the use of the term "source" since, every time a proposal has arisen for source-based units, it has quickly become apparent how problematic and unworkable it would be. It's perhaps best to clarify that (as I understand) what is being suggested here is the use of the convert template with the disp=output only flag, so if a number is quoted in imperial/USC we can still take that information from the source but display it in appropriate units only e.g. {{cvt|120|mi|km|disp=output only}} → 190 km.
Option 2: This seems to be just a more explicit proposal for source-based units, which I would oppose as described above.
Option 3: No, as in the real world there's no case in which the very marginal benefit of such unnecessary conventions is worth the clutter added by their inclusion. Our overarching guidance is to provide conversions only where they are, in context, likely to be useful to readers. If someone is hell-bent on knowing the diameters of the moons of Mars in furlongs, they have access to other conversion tools. This also makes me wonder exactly what "allow" means – allow individual editors to do whatever they want, regardless of MOS-level guidance or stylistic consistency across astronomy articles?
So if we were to adopt any of these, my !vote would be for a clarified version of the first. A more general comment would be that, as others have observed above, this is spelled out in realistically enough detail already at
WP:UNITS, so any guidance specific to this WikiProject should simply be a clarification of what that MOS guidance means specifically for the articles it maintains. It's important not to focus obsessively on problems that don't exist, or don't really manifest in article-space, so unless there is a recurrent problem with editors obsessively adding imperial/USC units to astronomy infoboxes, I'm not sure see a clear use case for this guidance.
Archon 2488 (
talk) 15:22, 1 March 2024 (UTC)reply
Option 1. I favor being slightly stricter than
MOS:UNITS and discouraging US/imperial units in infoboxes about astronomical objects, rather than just not requiring converting to them. Kwamikagami has just added (and I tweaked) advice to
MOS:CONVERSIONS which should address the concerns raised above about rounding and significant figures and retaining the original source units for verification (e.g. use disp=out for US/imperial quantities we want to keep for editor verification but display to readers in metric only). This means there is no reason to use US/imperial just because a source does so. Infoboxes are crowded, and the quantities involved are usually mind-blowingly large anyway, so it's more important to convert to the
astronomical system of units than to US/imperial units. So perhaps some wording like this:
I agree about restricting Imperial. What does it mean to anyone to say that Jupiter "weighs" X pounds? (Okay, we have pound mass now, but still.) No-one has any comprehension of what numbers that large mean. They're only useful for comparison, and units don't matter for that. The only figure likely to mean anything to anyone is that the Earth is 93M miles from the Sun, which I learned as a child, but the AU takes care of that: say that Jupiter is at 5 AU, and is doesn't matter if someone memorized the AU in miles or km. Lots of people have memorized the circumference of the Earth is 24k miles, but we hardly mention circumferences in the info boxes. Other than that, imperial is pretty meaningless.
I'd like to take it further, though. People have been going around converting exponential notation to SI prefixes (terameters and zetagrams or whatever). Those are also pretty much useless. IMO we should use exponential notation with basic SI (MKS) units.
Personally, I prefer the engineering convention of restricting exponents to multiples of three, even though my background is in physics, because it makes comparisons easier to have the same scale for similar objects. Certainly in tables (e.g. most massive objects in the SS), the header should specify the exponent so that the columns can be sorted easily, but I think it would be useful even in info boxes. But even if we go by the physicist convention, that's better than SI prefixes.
— kwami (
talk) 03:35, 18 May 2024 (UTC)reply
Superluminal astronomical objects
I am looking for a textbook or review to explain superluminal astronomical observations for
Faster-than-light#Astronomical_observations. AFAICT astronomers use the term "superluminal" as an observational category and thus the reviews of "superluminal sources" are matter of fact. The non-physical nature of "superluminal" does not even come up since (I assume) "everyone" knows that the term is empirical and no one things the speed of light limit is really exceeded. But I've not found a source that explains the issue. Suggestions?
Johnjbarton (
talk) 01:41, 11 April 2024 (UTC)reply
The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section.A summary of the conclusions reached follows.
I put together an early draft of a MoS guide for astronomy under
Wikipedia:WikiProject Astronomy/Manual of Style. It is intended to embed what has thus far been
tribal knowledge for this WikiProject and its associated task forces. For comparison, other such style guides can be viewed under the "By topic area" tab in the infobox. What do you think of this proposed guide? Do you disagree with what is stated? What else should it cover? I'm sure it can be significantly expanded. Thanks.
Praemonitus (
talk) 05:24, 11 April 2024 (UTC)reply
This is very helpful. I particularly appreciate the linking to other relevant guidelines. ~
Maplestrip/Mable (
chat) 06:40, 11 April 2024 (UTC)reply
I would suggest adding something discouraging the usage of computer-generated 2d/3d models in the lead image when suitable alternatives are available; this prominently applied to
Miranda, where a 3d model was used as the infobox image for several years in lieu of an image or image mosaic.
It may also be worth mentioning an apparent informal convention to use full-disc images of visited Solar System objects when possible, as the Sun, all nine planets (except for
Venus, which does not have any full-disc true-color images on commons), Pluto, Ceres, and all visited moons seem to follow this convention. A similar/analagous convention seems to be in place for imaged galaxies and DSOs too.
ArkHyena (
talk) 00:14, 15 April 2024 (UTC)reply
Makes sense. I've seen truncated images from Hubble in the lead image spot, which might not be ideal. A pair of examples are
NGC 5506 and
NGC 5634.
Praemonitus (
talk) 04:45, 15 April 2024 (UTC)reply
Of course! There may also be an additional caveat needed in that quality/accuracy still has priority over full disc. To provide a planetary example, this
[1] quarter-full image of Europa takes precedence over this
[2] full disc image, which is lower-resolution and exaggerated color.
ArkHyena (
talk) 20:58, 16 April 2024 (UTC)reply
As there didn't appear to be any serious objection to this proposal, I added it to the project sidebar so it can cook longer. Eventually, I hope it can be proposed as an addition to the MoS.
Praemonitus (
talk) 18:22, 30 April 2024 (UTC)reply
Abbreviations
A style question came up during a recent edit discussion: should infobox data entries preferentially use abbreviations or words? For example, 'Mly' or 'million light years'; 'AU' or 'astronomical unit'; 'Gyr' or 'billion years'; 'g/cm3' or 'grams per cubic centimetre'. In my mind the infobox should be kept compact by sticking to abbreviations, with the word usage being left for the article body. Is there a preference?
Praemonitus (
talk) 20:42, 12 April 2024 (UTC)reply
Okay, it's already covered by the MoS: "Where space is limited (such as tables, infoboxes, parenthetical notes, and mathematical formulas) unit symbols are preferred."
Praemonitus (
talk) 22:17, 12 April 2024 (UTC)reply
AI
It's probably not an issue yet, but should we mention AI-generated illustrations? For example, "AI-generated illustrations should be avoided unless their accuracy is confirmed by an astronomy expert. The AI system may have been trained using copyrighted material, so the legality of such use is unclear."
Praemonitus (
talk) 17:28, 17 April 2024 (UTC)reply
New here so I don't know if it has already been covered in a more general guide or such, but I believe mentioning AI-generated images is a good idea. It's better to cover everything before it becomes a problem, than having to adjust it later in my opinion.
AstroChara (
talk) 17:15, 18 April 2024 (UTC)reply
The copyright rules for AI-generated images is
commons:AI-generated media. If we prepare rules for objects that have never been photographed (such as exoplanets), gone millions of years ago (Theia, Mars with oceans), or just hypothetical (a terraformed Mars), they should be for any way to create such an image, be it AI, an artist's work or whatever.
Cambalachero (
talk) 19:40, 18 April 2024 (UTC)reply
I guess that artists and the astronomy experts are also trained using copyrighted material. Is the legality of the use of their work also unclear?
Johnjbarton (
talk) 23:05, 18 April 2024 (UTC)reply
You're taking the piss, right?
Primefac (
talk) 11:31, 19 April 2024 (UTC)reply
I think you are misunderstanding the issue with source materials and AI. Artists in all genres and authors in all fields re-mix material. That's
Standing on the shoulders of giants. The legality of that re-mix is never clear cut. That's why we have courts, law suits, and lawyers. Furthermore, the legal onus is on the person who causes the material to be displayed, not on the creator. I can copy
Monet in my home all day and night. Only when I sell my painting on the street will it be illegal. Similarly, the AI generation won't be illegal, uploading the image that infringes on a copyright will be.
Johnjbarton (
talk) 15:33, 19 April 2024 (UTC)reply
The legality of that is already established via the ramifications of plagiarism and the fair use law. No such ruling exists for AI; it's not even clear they can generate patents.
Praemonitus (
talk) 14:21, 19 April 2024 (UTC)reply
The discussion was copyright, not patent.
Johnjbarton (
talk) 15:21, 19 April 2024 (UTC)reply
Thanks for stating the obvious. I was making the point that the legalities on the use of AI output are far from settled.
Praemonitus (
talk) 19:26, 19 April 2024 (UTC)reply
I do agree here. The morals and merits of AI art can be debated here endlessly, but the primary concern is that laws surrounding AI art (and really, AI anything) are young and volatile, and potentially subject to rapid near-future changes. It would probably be wise to at least require AI-generated material to be clearly marked as such.
ArkHyena (
talk) 20:54, 19 April 2024 (UTC)reply
As for the way an AI generates an image, unless there is an actual case law over that, I would dismiss the whole thing of "they used copyrighted images for training" as immaterial. The only thing that is truly relevant is the final image, the result of the prompt. If that image is derivative, then delete (or don't upload), under the same conditions we would with any other non-AI image.
Cambalachero (
talk) 14:12, 19 April 2024 (UTC)reply
My concern is that there is current controversy about the use of copyrighted web content for training, which may ultimately lead to take-down orders.
Praemonitus (
talk) 12:37, 20 April 2024 (UTC)reply
Praemonitus: I like the way you worded this, and I agree with a fairly broad restriction on use of AI images without prior vetting and/or secondary sources. -
Parejkoj (
talk) 16:02, 19 April 2024 (UTC)reply
SIMBAD and NED
The guide contained the following entry, which was removed with
this edit:
However, in general they should not be cited as a source for the infobox data because the information is subject to change over time and comes from multiple overlapping sources. However, they are useful as a stable reference for the other designations listing.
with the comment "I disagree, it is better to directly cite SIMBAD or NED as sources for the infobox, as it makes it easier to verify the information."
I have seen cited data removed from these sources, so they should not be considered stable. An example of this is the coordinate information, which is subject to refinement over time, with the old data being replaced. Instead, in many cases they do provide stable references that can be used to directly cite the data. Hence, I'd caution against using SIMBAD or NED directly.
Are there any concerns about this?
Praemonitus (
talk) 12:35, 20 April 2024 (UTC)reply
Units
A few suggestions:
I think it would be good to pick one symbol for
astronomical unit, and I think right now we almost always use "AU".
Surface gravity should probably be displayed in
standard gravity units in addition to m/s2, and it would be nice to use "g0" instead of "g" to avoid confusion with grams.
Conversions between multiple SI expressions should be discouraged (e.g. both km/h and m/s, which I do see).
This section is a bit unclear on whether both SI and astronomy units should be used, or only one. In infoboxes (and prose where it's not excessive) I would argue for both. It's much easier to intuitively grasp huge distances and masses in AU, light-years, Earth gravity, Sun masses, etc., so very worthwhile to convert into these if necessary. I like the idea of converting to metric units as well because it allows intuitive comparisons across measurements - for example, how much bigger is the Earth than its orbit around the Sun? And as much as I want everyone to learn the scientific units from birth, it's a bit kinder to Americans who have come halfway and learned either metric or astronomy units but still haven't gotten a handle on the other.
I'm agnostic as to whether metric or astronomy units should be primary where both are given via conversion, and I'm actually fine with just making whichever the cited source is using as primary for convenience. But whatever the rule is it should be made clear up front.
The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.
hmm, ok, valid point. But list of landers and list of artificial objects are almost the same, the only major difference is that failed missions are listed in the first list and obviously not liated in the second.
Artem.G (
talk) 15:19, 15 April 2024 (UTC)reply
I'd say any material unique to the subsidiary lists should be merged to
List of missions to Mars; there's really not much point in having separate lists for landers, orbiters, and "artificial objects"
ArkHyena (
talk) 19:32, 18 April 2024 (UTC)reply
I do think having separate lists for landers and orbiters, alongside the general list of all missions, is reasonable. I think the "objects" list should be merged into the other two lists. The fact that orbiters have and will impact Mars is vaguely interesting for the orbiter list; memorials placed by landers is vaguely interesting for the landers list; but for the most part it's just a copy of everything else. ~
Maplestrip/Mable (
chat) 07:44, 1 May 2024 (UTC)reply
Wikisky shut down? (Affecting several important infobox templates)
I have heard rumors that wiki-sky, a.k.a.
Sky-Map.org, have shut down permanently. The page has long been used by a number of templates, used in thousands of astronomy articles on Wikipedia, in the form of links to a sky map (see
Messier 94 and
Alpha Centauri as examples; the link to the "coordinates" is at the top of the page). The page is currently offline, and has been for a few days. If this is indeed permanent, as I suspect, then we need a replacement, and some rather high-profile templates have to be edited quickly.
Renerpho (
talk) 15:17, 20 April 2024 (UTC)reply
Sounds like a job for a bot.
Praemonitus (
talk) 15:19, 20 April 2024 (UTC)reply
Hah! The site has just returned from the grave (meaning,
sky-map.org is back up and running, and the rumors I had heard were just that). I've rarely been happier to look stupid.
Renerpho (
talk) 02:12, 21 April 2024 (UTC)reply
Currently, there is no
C:COM:WikiProject Astronomy, but there is alot of astronomical files and needs for categorization, file description, file name corrections, and perhaps building galleries. There are such wikiprojects on Commons, such as
C:COM:WikiProject Aviation. The 2024 Great North American Eclipse talkpage has also been having debates on galleries lately, so building galleries on Commons can alleviate that --
65.92.247.66 (
talk) 21:36, 24 April 2024 (UTC)reply
I don't know if it will ever be a thing, but it doesn't look like it will become a Commons-based WikiProject anytime soon...
User:Hamterous1 (
discuss anything!🐹✈️) 22:11, 27 April 2024 (UTC)reply
G299.2-2.9
So I just checked the “Did you know...” section on the front page of Wikipedia. And there is this interesting article:
G299.2-2.9
The article says the object is 4,500 years old and 16,000 light years away from us. This doesn't make sense to me. Doesn't that mean its light has a speed of at least 3.6 times the speed of light?
Nightwatcher773 (
talk) 11:12, 29 April 2024 (UTC)reply
Well, it wouldn't've been 16,000 light years away from us 4,500 years ago, but I'm not sure if the expansion of the universe is that fast... ~
Maplestrip/Mable (
chat) 11:17, 29 April 2024 (UTC)reply
I believe you are correct; the object is 16k ly away, but the nova reached us 4500 years ago.
Primefac (
talk) 11:37, 29 April 2024 (UTC)reply
I think I might say that we are observing it ~4,500 years after the event, so the reader can put it into context.
Praemonitus (
talk) 16:35, 29 April 2024 (UTC)reply
Convention in astronomy is to refer to transient events as occurring at the time they are seen on Earth; light travel time is not included. So for example
SN 1987A happened in 1987 (when it was observed), not ~168,000 years ago (the time taken for light to travel that distance). There are good practical and theoretical reasons for this convention.
Modest Geniustalk 16:07, 29 April 2024 (UTC)reply
The article says
"It is approximately 20,500 years old, and is older than most other Type Ia supernova remnants."
with two references. This sentence makes no sense to me. Surely there have been Ia supernovae for billions of years.
Johnjbarton (
talk) 17:40, 29 April 2024 (UTC)reply
The 4500y date is correct according to the ref. This value is computed from the observed radius and a relation due to Sedov, see
Xu, Jian-Wen, Xi-Zhen Zhang, and Jin-Lin Han. "Statistics of galactic supernova remnants." Chinese Journal of Astronomy and Astrophysics 5.2 (2005): 165.
I applied the correction to the article.
Johnjbarton (
talk) 17:51, 29 April 2024 (UTC)reply
I suspect what they are saying is that SNRs don't last very long before dispersing into the surroundings.
Praemonitus (
talk) 19:03, 29 April 2024 (UTC)reply
Creating a new template
We currently have templates for citing catalogs, such as exoplanet.eu {{Cite EPE}}, Gaia DR2 {{Cite Gaia DR2}}, SIMBAD {{Cite simbad}}, among others. However, I miss a template to cite the NASA Exoplanet Archive, which is also a large catalog of exoplanets. The template name could be {{Cite NEC}} or {{Cite Exoplanet Archive}} and the style could be like this:
I don't know how to make templates, so anyone experienced could make this.
InTheAstronomy32 (
talk) 12:47, 30 April 2024 (UTC) Template links fixed, no content change.
Primefac (
talk) 12:50, 30 April 2024 (UTC)reply
Speaking to the technical aspect of it, you'd probably want something like:
A
quick search shows ~280 pages calling the exoplanet archive, so it's not unreasonable to have a template for the job. I'll wait for more feedback before creating it, though.
Primefac (
talk) 13:00, 30 April 2024 (UTC)reply
Being a deceased member of the IAU doesn't make someone notable. Anyone with a PhD in astronomy or related fields can join, a few years ago they opened membership to students studying for one. It's not some elite fellowship or award. (FWIW, I am an IAU member and don't pass
WP:NPROF.) Some of the people on that list will turn out to be notable for other reasons, but I expect the vast majority are not.
Modest Geniustalk 10:40, 10 May 2024 (UTC)reply
The article will be discussed at Wikipedia:Articles for deletion/2MASX J22550681+0058396 until a consensus is reached, and anyone, including you, is welcome to contribute to the discussion. The nomination will explain the policies and guidelines which are of concern. The discussion focuses on high-quality evidence and our policies and guidelines.
Users may edit the article during the discussion, including to improve the article to address concerns raised in the discussion. However, do not remove the article-for-deletion notice from the top of the article until the discussion has finished.
I've also nominated many other articles created by User_talk:Galaxybeing, and there are more yet to delete. If someone has a more automated way to go through these, that would be great: I've been adding them to the deletion list one at a time, and that's getting tedious. It may be more worthwhile to see if any of these new articles are notable enough to keep and just delete them all otherwise. We'll see if the author responds. -
Parejkoj (
talk) 17:41, 8 May 2024 (UTC)reply
What I typically do in such cases is search for papers on the object, and if those are lacking I slap on a {{notability}} template and let it cook for a while.
Praemonitus (
talk) 04:14, 9 May 2024 (UTC)reply
The problem is this user has created dozens (over a hundred by my estimate) of pages like this. They're almost all stubs with generic information pulled from catalogs and non-reliable sources (e.g. Go-astronomy, In-the-sky, and cseligman). I'd rather propose a "delete all of these pages and require the submitter to propose them for creation based on notability", but I'm not sure that there's a process for that. -
Parejkoj (
talk) 17:23, 9 May 2024 (UTC)reply
Understood, and I'm highly aware as I've been checking their WikiProject ratings. But I do have civility concerns about mass censoring an editor in that manner. Perhaps if there were a list of IC objects (since it's an extension of NGC) and we redirected the non-notable articles there? At least some of those articles do appear notable; I'd particularly check the ones with Hubble images, or more detailed information. Finally, the cseligman source at least seems pretty reliable.
Praemonitus (
talk) 18:08, 9 May 2024 (UTC)reply
Fair point on the civility concerns: I get a bit punchy when someone mass-creates a bunch of pages for random objects from catalog papers, since there are so many catalogs to pull from and so many junk webpages that just mindlessly compile those catalogs for pageviews. That said, just having Hubble images doesn't make something notable either: there are millions of HST images of objects, and unless it was a dedicated campaign for that ended in a paper for that object, it doesn't make it notable; the astronomical object notability guidelines are pretty clear. -
Parejkoj (
talk) 23:15, 9 May 2024 (UTC)reply
Right, but my experience has been that a publically-published Hubble image of an object usually means an associated article, which means potentially substantial content per
WP:GNG. To me it's a tell, and at least deserves more investigation.
Praemonitus (
talk)
Well we can argue about this until we're blue in the face, but if you search on "List of largest known stars" it'll point you to the right page. I'd say, "good enough".
Praemonitus (
talk) 14:00, 23 May 2024 (UTC)reply
What does this Ks/mu notation mean?
PSR J1903+0327 says "A near-infrared companion, KS = 18 (2.22 μ), is observed in
Gemini North images at its radio position..." What do "KS" and "μ" mean in this context? I see "μ" used in
Reduced mass and
Standard gravitational parameter but if it's one of those, I'm not exactly sure how that relates. This notation was in the
first draft of the article added by
Wwheaton, but they have not been an active editor for a few years, so I thought I'd ask here. Thanks! --
Beland (
talk) 03:29, 18 May 2024 (UTC)reply
I found a source
[3] for the Ks value. According to this
[4] article, Ks seems to be a line or band in the near-infrared. I'm not sure what μ is supposed to be; I assumed it was a different unit for magnitude but this pdf
[5] uses the symbol for
proper motion. Since it's a binary companion, that seems to be what the symbol stands for, but I can't be certain.
ArkHyena (
talk) 04:27, 18 May 2024 (UTC)reply
Aha! That means the "μ" is for
micrometre, as a wavelength of 2.22 μm is in the infrared. Oh, and actually it's the center of the
K band, according to that article. Based on the second source you found, 18 must be a
magnitude. Excellent fact hunting! --
Beland (
talk) 07:50, 18 May 2024 (UTC)reply
Good to hear that you've found out what μ meant! I spent a bit too long digging up proper motion figures for the pulsar and was quite confused as to why none of the figures matched the 2.22 figure from the article.
ArkHyena (
talk) 08:48, 18 May 2024 (UTC)reply
It should probably be listed as μm; I don't think I've ever seen just μ used.
Primefac (
talk) 11:54, 18 May 2024 (UTC)reply
Yeah, I already changed it to "μm" because that's what
MOS:UNITSYMBOLS requires. Across thousands of articles I've fixed recently, I've seen a few instances of just "μ" that I also changed. As
micrometre says, that was the official symbol until 1967. --
Beland (
talk) 18:49, 18 May 2024 (UTC)reply
"μ" alone should be
micron, which is equivalent to micrometre --
65.92.244.143 (
talk) 20:57, 2 June 2024 (UTC)reply
An explanation would certainly be welcome if you have any interest in researching it. --
Beland (
talk) 01:09, 3 June 2024 (UTC)reply
The parenthetical Ks should just be deleted. If the ref does not explain it and we don't understand it, it's not verifiable content.
Johnjbarton (
talk) 01:44, 3 June 2024 (UTC)reply
I've been finding some NGC object topics that were redirected to a list, but the list had no entry for that subject. Examples include
NGC 6237 and
NGC 6245. There are also redirects to pages with no information on the subject. An example of that is
NGC 6057. I think the reader would expect to find something about the subject on the target page.
Praemonitus (
talk) 14:20, 21 May 2024 (UTC)reply
Similar to my (probably to be rejected) deletion request list above, NGC 6057/NGC 6053 just shouldn't exist. It's not notable and all the entries for it are just catalogs. For things like that, just delete them. We can have someone add them to the list page if they want. -
Parejkoj (
talk) 18:04, 22 May 2024 (UTC)reply
There is a contradiction between the content of the article and the talk page. While the article explicitly says that HR 5171 is
contact binary, the latest talk page discussion says that it isn't based on a newer publication from 2019.
[6] This needs to be fixed in the article.
InTheAstronomy32 (
talk) 14:10, 23 May 2024 (UTC)reply
I have nominated
Sun for a
featured article review here. Please join the discussion on whether this article meets
featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Delist" the article's featured status. The instructions for the review process are
here.
750h+ 01:22, 24 May 2024 (UTC)reply
Hello! I've started
a discussion proposing some changes to the aforementioned template. Although this template is primarily concerned with planetary geology and Solar System-related topics, I invite you all to join the discussion and give your comments.
ArkHyena (
talk) 19:32, 24 May 2024 (UTC)reply
with a caption saying it shows the galactic longitude. The article says that this is measured from the galactic centre. Doesn't the picture show coordinates centred on our Sun, though? Or have I misunderstood?
Marnanel (
talk) 10:17, 29 May 2024 (UTC)reply
I believe you have misunderstood; it isn't centred on the galactic centre, it is centred on Earth and 0° runs through it.
Primefac (
talk) 11:51, 29 May 2024 (UTC)reply
I agree with @
Marnanel The way I see it, the image is centered on center of the Milky Way with a faint overlay coordinate system centered on the Sun. The caption claims:
Artist's depiction of the Milky Way Galaxy, showing the galactic longitude.
However, the image shows no longitude at all.
Johnjbarton (
talk) 15:00, 29 May 2024 (UTC)reply
Um... you say you see a faint overlay coordinate system centered on the Sun but that there is no longitude. That is the longitude.
Primefac (
talk) 11:51, 30 May 2024 (UTC)reply
The image shows the galactic longitude, and the caption in the article is correct about its orientation. It does not say "is measured from the galactic center" anywhere. Primefac has it right. How might we reword it to make it more clear? -
Parejkoj (
talk) 21:54, 29 May 2024 (UTC)reply
The longitude is not labeled and yet there are many labels in the diagram, including a coordinate system that does not match the topic. So it's fine if you already know what the galactic longitude is. The right fix is a different image. This image without the labels (which are cool) would be better.
Johnjbarton (
talk) 22:09, 29 May 2024 (UTC)reply
I'm confused: what do you think is incorrect about the diagram? It is labeled "Galactic Longitude" on top, and the coordinate system is the correct one: centered on the sun, 0º through the galactic center, right hand rule. The additional labels are not necessary, but I think they provide useful context. -
Parejkoj (
talk) 05:26, 30 May 2024 (UTC)reply
I agree, the overlaid coordinate system seems correct. It's just so finely ruled that it can't be viewed directly from the article.
Praemonitus (
talk) 13:53, 30 May 2024 (UTC)reply
Ok thanks for your patience. By magnifying the image and by reading your description carefully I can now indeed see the words "Galactic Longitude". If you don't know what it is, you don't know to look for the tiny letters at the top.
Vial of presolar grains from the Orgueil meteorite in suspension.
I've just uploaded an image of a vial of presolar grains, and while I've added it to Orgueil, I don't want to overwrite the image of
Stardust since that's both a great image and more dramatic. It doesn't actually show any presolar grains, however, so I thought I could help remedy that. It also may be pertinent for
AGB stars. I don't want to start slapping one of my own images all over a whole host of related articles, so any input on where this may fit best would be appreciated.
I will try and get an SEM image directly of presolar grains wider than 200px up at some point!
Warrenᚋᚐᚊᚔ 10:33, 5 June 2024 (UTC)reply
lookback time
Time is a pretty important issue in cosmology, but I have not found a good article. I did some work on
cosmic time but the reference point issue is not well referenced.
Some articles use the term "lookback time", but
lookback time was a redirect to
Before Present, an article about radiocarbon dating. I repointed it to
cosmic time, but this is not sufficient. I am unsure if "lookback time" is really related to the more technical cosmic time. Please review.
Johnjbarton (
talk) 17:59, 7 June 2024 (UTC)reply
Proposed change to minor planet / dwarf planet naming convention
Should their be an effort to modernize DR2/EDR3-based citations to DR3 when possible? Headbomb {
t ·
c ·
p ·
b} 17:38, 8 June 2024 (UTC)reply
That's already been happening to many star articles. However, it's not always possible, particularly for bright stars.
Praemonitus (
talk) 21:28, 8 June 2024 (UTC)reply
It is currently occuring, but will take some years to update all articles. Many articles still use astrometric data (parallax, proper motion) from Hipparcos as well.
InTheAstronomy32 (
talk) 16:05, 9 June 2024 (UTC)reply
User
Mvargic has been adding a lot of exoplanet art to Wikipedia, each image comparing the sizes of exoplanets to Solar System planets. However many of these exoplanets don't have known sizes - only their (usually
minimum) mass is known - and the images depict them with sizes "assuming Earth-like composition". This is misleading and I think these images should be removed. Any size comparison image for an exoplanet with an unknown size should be like
Exoplanet Comparison Gliese 581 c.png, showing a range of possible sizes for different compositions.
At least two of these images,
G 9-40 b.jpg &
GJ 9827 System.jpg, are also in blatant contradiction of known features (cf.
WP:ASTROART). The sizes of these planets are known so these have some informational value, but G 9-40 b & GJ 9827 d are depicted as rocky planets which is known to not be the case (their densities are too low).
SevenSpheres (
talk) 21:11, 15 June 2024 (UTC)reply
Some pictures (like those used in articles created by me,
HD 63433/
d and
GJ 3929/
b) decipts known features and seem to be true. I am not sure about other planets, most of these other planets have virtually nothing known about them except minimum mass and basic orbital parameters.
21 Andromedae (
talk) 21:58, 15 June 2024 (UTC)reply
Those are planets with known sizes (except GJ 3929 c) so those images do have some informational value. They don't "depict known features" beyond size but at least don't contradict known features.
SevenSpheres (
talk) 22:02, 15 June 2024 (UTC)reply
Support in removing most, if not all of them; these seem to clearly fall under
WP:FRINGE and/or
WP:SYNTH. These images serve little, if any, educational purpose, and only serve to confuse and give the false impression that we know more about these planets than we actually do.
ArkHyena (
talk) 15:46, 16 June 2024 (UTC)reply
Some images can be helpful, but these artistic illustrations should be added with caution.
21 Andromedae (
talk) 17:37, 16 June 2024 (UTC)reply
G 9-40 b & GJ 9827 d are not depicted as rocky but volatile-rich mini-neptunes with cloud decks and hazes of sulfur compounds
Mvargic (
talk) 16:48, 16 June 2024 (UTC)reply
Help needed to define "mean radius" and "mean diameter"