Talk:ʻOumuamua

Nature article

A free version of the article is available. Agmartin (talk) 17:39, 21 November 2017 (UTC)

Thanks. -- The Anome (talk) 18:05, 21 November 2017 (UTC)

Fantastic

This is a fantastic discovery. Am I the only person who read the name and also thought of "Papa-Oom-Mow-Mow"?

Well I for one thought of "Surfin' Bird" for much the same reason.[1] nagualdesign 21:07, 21 November 2017 (UTC)

Rama

I assume everyone realizes the similarity to the subject spacecraft of the book Rendezvous with Rama by Arthur C. Clarke. In fact, the section ʻOumuamua#Potential_space_mission parallels the opening of the book so closely as to make me suspect the section was written as a joke. Johnson487682 (talk) 19:09, 21 November 2017 (UTC)

For me it resembles "Pirx's Tale" from Tales of Pirx the Pilot by Stanislaw Lem which described an alien craft at a hyperbolic velocity of 90 km/s (Lem has guessed!) and conjectured to be a part of galactic swarm: "The perfectly symmetrical spindle had become a disk — better, a ring... a ship measuring twenty kilometers in length". By the way, rotating ring can also produce variation in brightness. — Ace111 (talk) 01:12, 22 November 2017 (UTC)

Certainly a worthy SciFi comparison. I recall Rama was obviously artificial when it slowed down as it approached, and its speed outside Jupiter of 100,000 km/h was only matched by ʻOumuamua inside the orbit of Mercury. I also see Rama (50km) was ~100 times larger in length. I admit when I heard of this being first discovered, 1I, I wondered if it was one of many heading our way from the same source, although Rama might suggest this first probe as exploratory, while ʻOumuamua II and ʻOumuamua III are still coming, and we should be ready to intercept them. Tom Ruen (talk) 11:04, 22 November 2017 (UTC)

First thing I though of! Gaius Cornelius (talk) 20:11, 27 November 2017 (UTC)

It may sound trivial but perhaps this is worthy of mention at the end of the article? It's been mentioned on APOD and [https://www.nytimes.com/2017/11/22/science/oumuamua-space-

asteroid.html The New York Times] (although I'm not sure if either of those are considered reliable). nagualdesign 22:42, 27 November 2017 (UTC)

The shape really is not that far from 2003 SD220 in 2015, or 1865 Cerberus. -- Kheider (talk) 13:13, 29 November 2017 (UTC)

i am not sure what to believe. i found object sd220 mixed up with it in google images and cannot explain why we don't have a picture of it yet. radar or light (reflectance and radiative). my page looks at the other image as a possible hidaway for the overall coverup. http:// the ubie . com / is-it . htm . Perhaps you can help explain the other problem that the argument of periheilion 241.7 looks like it should be about sep 4 or 5 --not the september 9 stated.

72.94.230.198 (talk) 20:47, 30 November 2017 (UTC)

Evidence of interstellar origin

Does the section ʻOumuamua#Evidence of interstellar origin say anything that is not already covered in the article? -- Kheider (talk) 21:55, 21 November 2017 (UTC)

In a word, no, but maybe 23h112e will have something to say about that. nagualdesign 22:23, 21 November 2017 (UTC)

What is the curent position of head of US gov. about 'O origin ? — Preceding unsigned comment added by 99.90.196.227 (talk) 08:34, 22 November 2017 (UTC)

He probably thinks very little about it. I wonder what the pope thinks? Or Bruce Willis? nagualdesign 22:17, 22 November 2017 (UTC)

@Kheider:

Yes, it is simply for those who react with incredulity to the statement of an object being known as a fact as originating from somewhere outside of the solar system, which includes those who aren't practicing routine astronomical observation, and those without degrees in allied subjects (those whose minds are therefore consequently oriented to ways of thinking about things which predisposes them to find understanding astronomical and astrophysical subjects less easy), i.e. a synopsis for people who can't or don't want to sift through the data and terminology and want only to see the proof, for instance those who have employments and are time-pressured by other commitments but are interested because of the historical importance and are interested due to the fact of the article being on the opening page yesterday and today. 23h112e (talk) 17:29, 22 November 2017 (UTC)

---

source: http://www.skyandtelescope.com/astronomy-news/astronomers-spot-first-known-interstellar-comet/ "...the fact that A/2017 U1 is coming from a spot only 6° from the solar apex, the direction that our Sun is moving (at about 20 km/s) through its interstellar neighborhood and thus, statistically, the most likely incoming direction for an interstellar visitor..."

& source: Stephen Webb Measuring the Universe: The Cosmological Distance Ladder p.118

How this fact indicates the greater likelihood of interstellar orign. 23h112e (talk) 17:43, 22 November 2017 (UTC)

Now that the section is being fleshed out I agree that it's a good idea to have a specific section for those looking for what the actual evidence is. It also means that the more technical details have a nice home while the lead section can avoid baffling 90% of readers. I must say though, 23h112e, that claiming anything to be known as a fact is not a very scientific point of view. There is good evidence - strong evidence - but that is all. And that's more than enough. nagualdesign 22:17, 22 November 2017 (UTC)

The Velocity at infinity (or at least near infinity) is what is most important. Eccentricity is just a function of the perihelion point. If perihelion was further out the eccentricity would be notably greater. -- Kheider (talk) 03:09, 23 November 2017 (UTC)

What's also interesting isn't just a significant v_{∞ but that it passed so close to the sun, so nearly 100% of its initial kinetic energy was radial, directed nearly exactly at the sun. So it was a literal bullseye into our solar system, from where ever it came. Coincidents happen but mainly if we someday find out hundreds of similar sized objects with hyperbolic trajectories are annually passing through the solar system, but we've just been missing them. Tom Ruen (talk) 17:57, 23 November 2017 (UTC)}

With a Geometric mean diameter of less than 100 meters, Oumuamua would simply have been too faint for automated software to detect if it had passed much further from the Earth. I do expect automation to start detecting many of these in the next ten years or so as surveys become more sensitive. -- Kheider (talk) 18:50, 23 November 2017 (UTC)

Size

This article is missing all information on the object's size. -173.187.77.148 (talk) 00:57, 22 November 2017 (UTC)

the size matters.

just put size is intergalactic ... from another galaxy: Are all of you still against original thinking ?

but if not, according to my calc (if spherical) it be a bal quoter kilometre across with mass > 8 Mton < 10e10 kg

— Preceding unsigned comment added by 99.90.196.227 (talk) 02:41, 22 November 2017 (UTC)

I doubt that many of the editors here are against original thinking! However, Wikipedia doesn't permit original research, if that's what you're trying to ask.

I'd say you're probably thinking so far outside the box here that the box must be nearing your cosmological horizon. ʻOumuamua is travelling at approximately 0.0000878 c. The nearest galaxy, Andromeda, is around 2.537 million light years away. By my calculation, if ʻOumuamua came from Andromeda it would have to have been travelling for over 28 billion years; more than twice the age of the Universe.

I'm sure that your calculations of ʻOumuamua's mass are 100% reliable though. And a bal quoter kilometre across, you say? I expect someone will add that info to the article at some point. Thank you for your contribution. nagualdesign 04:09, 22 November 2017 (UTC)

If it was intergalactic it would be moving another 10 times faster: Oort cloud = ~2km/s, galactic disc = ~20km/s, intergalactic = ~200km/s. -- Kheider (talk) 05:55, 22 November 2017 (UTC)

`nagualdesign :N' calculation may contain systemic bias since empirical search indicating a lot of sources 3.57e-13 x earlier about:'Obuamua recent origin. You just assume and not state why; why you assume constant speed during 2 Universe lifetimes. Are you shure tehere were about Andromeda Galaxy? We should add section about fake news like above weather.com. It will benefit 500 x more readers (see:alexa rank) who may be cyberneted by oogle&a to from another galaxy dezinfo. — Preceding unsigned comment added by 99.90.196.227 (talk) 08:30, 22 November 2017 (UTC)

I assure you that there was no systematic bias in my calculation, since it was just basic arithmetic. I was also pretty clear about the basic assumptions I was making (ie, assuming a constant velocity over a fixed distance). The truth is that Andromeda didn't exist 28 billion years ago, so the equation makes no sense. In case it isn't obvious, my comment wasn't intended to be taken entirely seriously. I was poking fun at the fact that you'd confused interstellar (from another star system within the Milky Way) with intergalactic (from another galaxy), without considering the vast difference in scale that this would imply. Galaxies are around 5 orders of magnitude more distant than stars of the Milky Way. nagualdesign 20:26, 22 November 2017 (UTC)

Exiting the Solar System?

Since I'm not a scientist, I'm not clear on why the object is expected to exit the Solar System. I would expect it to be affected by the Suns gravity, and be captured by it, causing it to fall into an orbit. Why the object is not likely to do that is not explained in the article. Can someone with a little expertise in these matters clarify that? Thanks. Juneau Mike (talk) 14:49, 22 November 2017 (UTC)

Note 13 of the Table "1I/'Oumuamua velocity with respect to the Sun" explains this. When outbound 1AU from the Sun, the object was going 49.67 km/s with respect to the Sun. But to be captured by the Sun's gravity it would need to be moving less than 42.1219 km/s at 1AU. (I had not added this directly to the article as I wanted to avoid any appearance of Wikipedia:No original research. But I went ahead and was Wikipedia:Be bold.) -- Kheider (talk) 16:18, 22 November 2017 (UTC)

It's nothing more than Escape velocity, but perhaps Conservation of energy is involved too, changing Gravitational potential energy into Kinetic energy and back into potential energy when it leaves. Tom Ruen (talk) 18:19, 22 November 2017 (UTC)

@Kheider: Sorry to be a stick in the mud but I recommend against including any OR. As Tom mentioned, it's a simple case of ʻOumuamua exceeding the Sun's escape velocity, and this way of explaining it is also more accessible than talking about calculated velocities at particular distances. nagualdesign 20:36, 22 November 2017 (UTC)

I made the edit. If any reader wishes to know more about the specifics they can visit Escape velocity. If you'd prefer to keep it as it was you might be able to copy/paste a reference from here. nagualdesign 21:29, 22 November 2017 (UTC)

I swapped a paragraph from the lead with one from Evidence of interstellar origin (diff) per MOS:INTRO. I hope that helps make the article more accessible, while providing the specifics for those who want to weigh up the evidence themselves. nagualdesign 22:06, 22 November 2017 (UTC)

Escape velocity explains what is happening quite well. I appreciate several of you answering my question. Thanks! Juneau Mike (talk) 20:51, 24 November 2017 (UTC)

Voyager 1

In the article, it says the asteroid is expected to 'leave the solar system' in about 20000 years. Given the velocity, would that exit not be expected to be much sooner? Voyager already left the solar system, and its velocity is not many orders of magnitude larger than the comet. — Preceding unsigned comment added by 198.202.130.252 (talk) 08:09, 23 November 2017 (UTC)

Actually Voyager 1 has NOT left the Solar System. It has passed the heliosphere, but is well inside the Oort cloud. I was annoyed when press releases described it as such. Voyager 1 is only 141 AU from the Sun and thus has ~100,000 AU to go. Nemesis (hypothetical star) was suppose to orbit 95,000 AU from the Sun. The comet's ($v_{\infty }\,\!$=26 km/s) while Voyager 1 is only going 17 km/s. -- Kheider (talk) 09:29, 23 November 2017 (UTC)

Exit Date?

In the opening, it says the object is expected to leave the solar system in about 20,000 years. Lower down, it says the object left the solar system on 20 November. ??? — Preceding unsigned comment added by 202.246.252.97 (talk) 00:24, 24 November 2017 (UTC)

I have removed the misleading text. I am not even sure that lead paragraph in the Observations section does anything useful. -- Kheider (talk) 05:33, 24 November 2017 (UTC)

from whence

The article is locked so I can't do this myself, but "from whence" is just ridiculous english trying to sound educated. Whence literally means "from where" so from "from whence" means "from from where". Someone with editing-rights should correct that. — Preceding unsigned comment added by 217.254.45.23 (talk) 15:33, 22 November 2017 (UTC)

It may be technically redundant, although writers have used "from whence" for centuries. The article currently says "from the direction from whence it came" which does sound like something from the Department of Redundancy Department. Jonathunder (talk) 16:46, 22 November 2017 (UTC)

I rephrased it to "from the direction of its approach." Jonathunder (talk) 16:52, 22 November 2017 (UTC)

Verily I say unto thee; Lord, what fools these mortals be! Everything has beauty, but not everyone can see. But, for my own part, it was Greek to me.

Only kidding. I don't think anybody was "trying to sound educated" any more than using 'long words' is the sole dominion of sesquipedalianists. "From whence" is perfectly good English, but alas... nagualdesign 22:45, 22 November 2017 (UTC)

Dimensional ratios

There's reason to wait for "final best estimates" if such a thing is possible, but seeing the artistic image as grossly exaggerated, I attempted a rescale by 65% shorter length, so its closer to the 180x30x30m dimensions given in this article. Tom Ruen (talk) 18:53, 22 November 2017 (UTC)

Original

Reduced to 65% on long axis

I think as more time passes the calculations of the shape of this object will shift to a less cylindrical model. Will have to wait for those RS estimates.

I see someone inserted my compressed image to the stat table, while the "In the news" image is still the crazy long original one. Tom Ruen (talk) 15:51, 24 November 2017 (UTC)

What about eso1737e? Askaniy (talk) 14:01, 26 November 2017 (UTC)

eso1737e

I'd say let's just wait and see. Tom's edit, currently in the infobox, closely matches the 6:1 ratio that's the current best estimate. Given that the oscillating light curve on which the estimate is based might just as easily be caused by a (more) spherical two-tone object we're talking about giving form to something that's largely guesswork, and I'd recommend against any action that might imply an increased sense of certainty. In other words, each time we update the infobox many people might mistakenly believe it to be based on new evidence, which it isn't. nagualdesign 17:34, 26 November 2017 (UTC)

Extrasolar versus interstellar

The section on Evidence of interstellar origin currently begins with:

Evidence of interstellar origin

By mid November 2017, astronomers were certain that it was of extrasolar origin...

I find this apparent minor contradiction a little irksome. The word extrasolar might be defined as "orbiting a star other than the Sun", and the Extrasolar object article pretty much confirms that. While interstellar means "occurring or situated between stars". I suppose, at a push, they're pretty much synonymous in this context but it seems kind of funky to me. ʻOumuamua came from interstellar space, we can be certain of that. And asteroids form within the accretion discs of stars, right? But how certain are we really that ʻOumuamua once orbited another star?

I would have simply edited the sentence in question to read, "By mid November 2017, astronomers were certain that it was of interstellar origin...", but origin also denotes "the point where something begins". I also note that, according to Extrasolar object, the only known extrasolar asteroid is in orbit around GD 61, whereas ʻOumuamua is the only known hyperbolic asteroid.

In short, as a merciless pedant I would probably describe ʻOumuamua as "an interstellar object of extrasolar origin" since, as far as I'm aware, asteroids don't form in interstellar space. So now I'm thinking that we should change any instance of "interstellar origin" to "extrasolar origin", including the section title.

Any thoughts? nagualdesign 08:13, 23 November 2017 (UTC)

I agree. Tom Ruen (talk) 17:42, 23 November 2017 (UTC)

I see that the article has been reconfigured to good effect in my absence. Thank you to whoever did that. I made a couple more minor amendments so that the article was consistent with the references while satisfying the reasoning outlined above. I for one will sleep easier tonight. Keep up the good work! nagualdesign 03:30, 24 November 2017 (UTC)

Table: Inbound velocity at 200 AU from the Sun

What is the significance of this table in the Observations section? I see no references to this table from the text. Boardhead (talk) 14:34, 23 November 2017 (UTC)

It is produced with JPL Horizons. What it shows is that no other known object comes even close to matching the inbound velocity of Oumuamua. All of them are ~3 km/s inbound at 200 AU from the Sun while Oumuamua is 26.5 km/s (10x greater). The velocity at infinity (near infinity) is what is what is most notable about Oumuamua. Most of these objects are well known. -- Kheider (talk) 15:45, 23 November 2017 (UTC)

Thank you for this information. It sounds like you are stating this is a list of the highest-velocity objects yet discovered in the solar system. It would be useful to state this in the article. Boardhead (talk) 17:45, 23 November 2017 (UTC)

Many names confusing

Is the official, formal or systematic name 1I/ʻOumuamua or 1I/2017 U1 (ʻOumuamua)? (See the last line in the lead and section Naming_of_comets#Current_system.) And since we have a nomenclature section, shouldn't the alternate names, including previously designated like C/2017 U1, be put down there?

Once we've settled that, should Wikipedia call it 1I/ʻOumuamua or ʻOumuamua? Both designations have about the same number of occurrences in the article. Unless there is some special reason for calling it 1I/ʻOumuamua in one sentence and then simply ʻOumuamua in the next, we should reduce the spelling to one form, both in the article and in all the other Wikipedia articles that mention it.

I guess this would be a formal consensus-building discussion: should we have one name for one object and, if so, what name should it be? --RoyGoldsmith (talk) 21:03, 23 November 2017 (UTC)

 Done - FWIW - found/replaced instances of 1I/ʻOumuamua with ʻOumuamua - to be consistent - *entirely* ok w/ me to rv/rm/ce edit if not ok of course - hope this helps in some way - in any case - Enjoy! :) Drbogdan (talk) 13:47, 24 November 2017 (UTC)

Reverted as it is probably better to be more selective instead of a universal search and replace. "'1I/ʻOumuamua" is still the current name and we should certainly not be changing reference titles. It might make sense to call it "1I/ʻOumuamua" during the first occurrence of each section. I also think tables should use the more formal (longer) name especially when there is plenty of room in a column. In other articles, I think the proper name 1I/ʻOumuamua should be used (at least during the first mention). Having said that I do not see why Wikipedia NEEDS to define a hard rule for this. -- Kheider (talk) 14:09, 24 November 2017 (UTC)

I think we should stick with the common name 'Oumuamua (WP:COMMONNAME), which is the name that now seems to be used by the popular press, e.g., The New York Times. Meech et al refer to the object only once with the MPEC form "1I/2017 U1 ('Oumuamua)" and consistently thereafter simply use 'Oumuamua. That's surely an acceptable name to use for this object. Of the older designations, "A/2017 U1" is still found on some web pages, so at least "1I/2017 U1 ('Oumuamua)" and "A/2017 U1" should probably be mentioned as formal and former names respectively in the lead. All the other forms of the name could be included in the nomenclature section. I haven't seen "1I/'Oumuamua" used all that often, but I haven't looked at all the sources. --Robert.Allen (talk) 17:39, 24 November 2017 (UTC)

I agree that common names work better in prose, since "1I/ʻOumuamua" is jarring to the internal monologue. Even worst if you try to read the article aloud. I suggest that (if I'm not already late to the party) all instances should be changed to ʻOumuamua in prose, tables and other instances should follow the style of the references perhaps, and of course the references themselves should be left verbatim. nagualdesign 19:09, 24 November 2017 (UTC)

We should treat this the way we do Ceres (dwarf planet) or 4 Vesta, which are featured and good articles, respectively. After the first sentence, where full names are given, use just the short common one. It's similar to what we do for people or places. Jonathunder (talk) 19:35, 24 November 2017 (UTC)

I have noted that many people love to expand comet names like C/1980 E1 to C/1980 E1 (Bowell) when editing Wiki articles. Not saying that is important, but just an observation I have made. I have left "1I/ʻOumuamua" in the 200 AU table because all of those objects are listed by their formal names. -- Kheider (talk) 19:39, 24 November 2017 (UTC)

I'm just saying that two names for the same object is confusing, especially for non-astronomers. According to MPEC 2017-V17, the permanent designation is "1I" alone; the common name will be "ʻOumuamua". (The IAU regards designations as different from names.) 1I/2017 U1; 1I/ʻOumuamua and 1I/2017 U1 (ʻOumuamua) are correct forms for referring to this object. A/2017 U1 and C/2017 U1 are previous designations.

I'm starting a poll in the next subsection, to build consensus or not for this topic. This is not a vote. It is merely an attempt to see where people stand as of right now.

Further discussion about this topic should be placed here immediately before the Consensus building subsection. Actually votes and their explanation should go on the other side.

Further discussion goes here vvv --RoyGoldsmith (talk) 23:45, 25 November 2017 (UTC)

I only see the name "2017 U1" mentioned in historical context. It is fine having 2017 U1 in the "Asteroidal nature" section since that was when the object was first discovered and did not have a formal name. That section is also largely about why it changed from being "C_omet/" to an "A_steroid/". -- Kheider (talk) 01:50, 26 November 2017 (UTC)

Consensus building

This side (subsection) contains a poll of two topics:

1. Should we have one name for the object defined in this article (other than the first sentence in the lead and the Nomenclature section)? and
2. If so, what is that name?

The title of the Wikipedia article (currently ʻOumuamua) we'll leave until we have some more opinions on these first two points.

•  Yes - ʻOumuamua. Because of WP:COMMONNAME and examples Ceres (dwarf planet) and 4 Vesta. --RoyGoldsmith (talk) 23:57, 25 November 2017 (UTC)

•  No - It is also appropriate to call it 2017 U1 in the "Asteroidal nature" section since that was when the object was first discovered and did not have a formal name. It was also changed from a "C_omet/" to an "A_steroid/". I think a more proper comparison would be 1P/Halley. I think the naming issue has already resolved itself. -- Kheider (talk) 01:50, 26 November 2017 (UTC)

• I think it should be referred to as ʻOumuamua in most of the article, per WP:COMMONNAME. No opinion on the Asteroidal nature section. Kaldari (talk) 03:42, 26 November 2017 (UTC)

• Comment - Without wishing to disparage your efforts, Roy, since consensus building is a laudable endeavour, I think we've already resolved this issue. You made your case at the start of this section (before this subsection) and Kheider, Robert.Allen, myself and Jonathunder all responded. (And Kaldari agrees.) The consensus was that we should follow WP:COMMONNAME and stick with ʻOumuamua for the name of the article, as well as in prose, while there are a small number of places where the official designation is more appropriate. I'm not sure what you're going to achieve by putting this to a !vote. All (or most) discussions on Wikipedia talk pages are a form of consensus building, without having to explicitly state that they are in some way 'official'. If you strongly disagree with a small number of editors and seek further input from the wider community you could try a request for comment, where the final consensus might carry more weight. A better idea in this case might be to form a more convincing argument. I'd certainly be willing to change my mind, or to have it changed, if I found your case compelling. With all due respect I don't think you've done that here. Sincerely, nagualdesign 17:08, 26 November 2017 (UTC)

• I'm sorry. The number of "misspellings" had gone down greatly in the last 24 or 48 hours before I wrote this but I didn't notice it. The alternate form "1I/ʻOumuamua" only exists now only as the last line in the table "Inbound velocity at 200 AU...". Should it be changed to ʻOumuamua? --RoyGoldsmith (talk) 23:39, 26 November 2017 (UTC)

• Kheider gave a good reason for leaving the table the way it is. Jonathunder (talk) 10:29, 27 November 2017 (UTC)
• Ditto. The left-hand column of that table ("Object") lists designations (with names written in parentheses if they are not part of the designation). nagualdesign 16:51, 27 November 2017 (UTC)

Votes go here ^^^ --RoyGoldsmith (talk) 23:45, 25 November 2017 (UTC)

Pronunciation?

Could we get a pronunciation for the name? I get 99.9% of my news from text sources, so have not heard it pronounced yet. Thanks, †dismas†|^(talk) 16:15, 24 November 2017 (UTC)

Ignore me. I see now that it's in the infobox. I was expecting it to be in the prose. Possibly next to the name in the lead sentence. †dismas†|^(talk) 16:19, 24 November 2017 (UTC)

I like it better just in the infobox personally. Less clutter. Kaldari (talk) 03:43, 26 November 2017 (UTC)

The name

Perhaps there should have been a nod at Rendezvous with Rama. 89.197.114.132 (talk) 16:17, 24 November 2017 (UTC)

Yes, there are some good sources for this: e.g., [2], [3]. --Robert.Allen (talk) 17:59, 24 November 2017 (UTC)

The second link "The thing is that the story seems awfully prescient. A/2017 U1 has hurtled in on the sort of trajectory Clarke envisaged for Rama. In Rama’s case, it was intentionally done to maximise the ‘slingshot’ effect – getting a free speed boost from the Sun’s gravity well." ... we'd definitely have some great circumstantial evidence of "intelligent design" if the outbound direction corresponded to a known neighboring star, and if NOT, perhaps we'll discover one if we look very carefully in that direction! Also since we didn't see it before perihelion, we don't actually know if there were any course corrections that helped guide its final approach, and its direction of origin might not be safely extrapolated backwards from its current trajectory. Tom Ruen (talk) 19:45, 24 November 2017 (UTC)

Course corrections, eh? Hah! The idea's pretty fanciful but not outside the realms of possibility, I suppose. If you'd like, and if others don't disagree, perhaps you'd like me to add a row of windows to the artist's impression in the infobox? (Not really!) nagualdesign 20:46, 24 November 2017 (UTC)

I wasn't thinking windows, but a radio dish would certainly help us figure out where it really came from. [4] Tom Ruen (talk) 21:19, 24 November 2017 (UTC)

It's my understanding that a hyperbolic trajectory can either speed up or slow down a given orbit. Does anyone know whether the I1's trajectory got faster or slower as it passed by the sun and by how much? If significant, this could be put in the article. --RoyGoldsmith (talk) 00:16, 26 November 2017 (UTC)

The speed is basically the same inbound and outbound. ==> "Its incoming and outgoing speeds as it went through interstellar space were 26.33 +/- 0.01 km/s." -- Kheider (talk) 00:22, 26 November 2017 (UTC)

User:RoyGoldsmith, do you mean like a Gravity assist? The inbound speed and outbound will be equal in the frame of reference of the assisting body (sun), but since the direction is changed, there can be change in relative speed from another frame, like a star of origin. Tom Ruen (talk) 03:21, 26 November 2017 (UTC)

I too wonder if it got a gravity assist (slingshot), as it is so common with interplanetary spacecraft. If not, why it did not happen? Perhaps other readers (and editors) would like to see a line explaining that? Cheers, BatteryIncluded (talk) 17:58, 26 November 2017 (UTC)

As I understand it, it all depends on the trajectory of ʻOumuamua relative to the trajectory of the Sun. The last sentence of the lead currently reads, "The direction of motion of ʻOumuamua is 6° from the solar apex." so I expect it did get a kick. The only problem is that if someone here performs the calculation it wouldn't be admissible (per WP:OR) and there seems to be a dearth of reliable sources on this specific topic. nagualdesign 18:20, 26 November 2017 (UTC)

What is needed, as in other cases, is 'WP - the extended version' - a certain number of parallel articles where OR is included, 'material known to be accurate' is presently only in blogs and suchlike (we all have our own examples). Jackiespeel (talk) 22:13, 26 November 2017 (UTC)

I'm only saying that, with 40-plus days of observation arc, the course (including the instantaneous velocity of each point) should be well known. Is the total energy of ʻOumuamua after perihelion greater or less than the total energy before the fly-by? If ʻOumuamua has more energy after then the sun will have transferred some energy into the object and we've increased our orbital eccentricity. However, if it has less energy then we've lessened our eccentricity (say from 1.2000002 to 1.2000001). One can imagine a race of Krell (from Forbidden Planet) precisely throwing a rock so that it will, after dozens or hundreds of fly-bys, each one giving up a minute fraction of its speed, be captured (eccentricity < 1) by some star in another arm of the galaxy a billion years from now. --RoyGoldsmith (talk) 00:41, 27 November 2017 (UTC)

I imagine something more like something breaking off from the stress of the close solar encounter. That could change its momentum and direction. Unfortunately we have no observations near perihelion to know anything about its inbound orbital parameters. Everything there is extrapolating backwards assuming there was no change. Tom Ruen (talk) 20:36, 27 November 2017 (UTC)

Speed discussion

Somewhere this name section turned into a speed discussion. It looks like from the JPL Horizon data that the outbound velocity is minutely less than inbound. I am not sure of the physics but a close encounter between two moving masses should result in some transfer of kinetic energy. The amount is more apparent in the smaller mass. Did one of the references say that the trajectory was "retrograde"? I think this results in a slowing. P.S. the trajectory need not be hyperbolic.User-duck (talk) 12:50, 28 November 2017 (UTC)

2017 U1 had a flyby delta-V of about (26.32824 - 26.34089) or -12.7 m/s. So 2017 U1 lost a small amount of speed. -- Kheider (talk) 12:52, 29 November 2017 (UTC)

Oort Cloud

Given that the Oort cloud is the cosmographical boundary of the Solar System, are there any citations as to when it leaves the outer limits of said system? kencf0618 (talk) 18:43, 26 November 2017 (UTC)

Not really as many authors define it somewhat differently. The boundary of the Oort cloud is in constant flux as the outer edge is only loosely bound to the Solar System and subject to perturbations by the galactic tide and passing stars. -- Kheider (talk) 18:57, 26 November 2017 (UTC)

ʻOumuamua certainly entered the inner solar system though within the orbit of Mercury, and exited it within the orbit of Mars. It'll be very interesting to see what Pan-STARRS observes over time! kencf0618 (talk) 18:19, 27 November 2017 (UTC)

Just out of curiosity: 'Oumuamua is inside the orbit of main-belt asteroid Ceres (aphelion: 2.97AU) from mid May 2017 to early Jan 2018. And if we are lucky 'Oumuamua might show some cometary activity while outbound over the next month. -- Kheider (talk) 18:50, 27 November 2017 (UTC)

Table alignment

I've just been wrestling with the CSS mark-up to get the two tables to sit well. (See before and after.) The problem was that one of them was stacked against the infobox at certain resolutions, resulting in a bit of paragraph in the middle that was only 2~3 words wide. I think I've fixed it now. Let me know if it doesn't look good on your own monitor/phone/tablet. Cheers. nagualdesign 21:39, 26 November 2017 (UTC)

(Edit conflict) I left the tables in the same order in the mark-up, which has actually caused them to render in the opposite order than before. Swapping them would be a simple matter, if anyone prefers it that way, although having the narrower table opposite the infobox is probably a good idea as it maximizes the space between them. It also means that the sentence, "Extrapolating the orbit backward, the asteroid is calculated to have gone through perihelion on 9 September," is next to the table that shows "perihelion", which is helpful. nagualdesign 21:46, 26 November 2017 (UTC)

I noticed that before. It looks better now in my laptop. BatteryIncluded (talk) 21:42, 26 November 2017 (UTC)

Good. nagualdesign 21:46, 26 November 2017 (UTC)

The William Herschel Telescope image is now on the left, which works better. I removed the {{clear}} that User-duck placed as I didn't like the look of all that whitespace. Arguably, having the proceeding section header pushed into the middle of the page isn't particularly easy on the eye either. Feel free to add that back in. I'll stop playing with it now. nagualdesign 22:17, 26 November 2017 (UTC)

I now realize I should have been using this forum before. I moved the image up slightly and restored the {{clear}}. I agree about the whitespace BUT that is an issue with the template. It does not show up if the screen is narrow enough that the text wraps around an image.User-duck (talk) 23:12, 26 November 2017 (UTC)

That looks much better now (on my laptop), thanks. I'd moved the image down a tad because I didn't like the way the subsection header was removed from the text. I didn't even consider moving the image up a tad! Funny how we sometimes miss an obvious solution, isn't it? And the {{clear}} also functions much better now. nagualdesign 00:43, 27 November 2017 (UTC)

Table notes

How do you get the same note for both tables without using a generic cut&paste for the whole note? <ref group="n" name="Horizons"> was what I was looking for. -- Kheider (talk) 23:26, 26 November 2017 (UTC)

Looks like you managed to work that out. I'm guessing you were just missing the /> at the end. nagualdesign 00:43, 27 November 2017 (UTC)

US or British English

Time again for that age-old question: which variety of English? I see both. I used US, noted a GB article.User-duck (talk) 23:15, 26 November 2017 (UTC)

With proper deference to titles and quotes.User-duck (talk) 22:06, 30 November 2017 (UTC)

Is the Inbound Velocity table original research?

The notes on the "Inbound velocity at 200 AU from the Sun comparing ʻOumuamua's interstellar speed to Oort Cloud objects" (in Observations > Trajectory) say, I think, that the table was built using the JPL Horizons tool. Who ran it and in what publication did he publish the results? This should be an inline citation. Or was it some well-intentioned Wikipedian/editor manipulating the tool and the only place that the table exists is in Wikipedia? If so, I think the table is an example of WP:OR and should, most likely, be removed. Or am I missing something? --RoyGoldsmith (talk) 23:58, 26 November 2017 (UTC)

I did it and it passes Wikipedia:Verifiability. -- Kheider (talk) 00:00, 27 November 2017 (UTC)

I verified a couple of entries, a different option is required to get distance (AKA range), and corrected the note. Compiling these tables was a lot of work and I appreciate the effort.User-duck (talk) 00:43, 27 November 2017 (UTC)

P.S. The (1.89×10¹³ km / 26.33 km-per-sec / 60 seconds-per-min / 60 minutes-per-hour / 24 hours-per-day / 365.25 days-per-year = 22,700 years) calculation could be consider WP:OR. I consider it value added. (once I corrected it) User-duck (talk) 00:43, 27 November 2017 (UTC)

In my opinion, unless it is published in a reliable source other than Wikipedia, it does not pass Wikipedia: No original research. I quote from the first paragraph: "This includes any analysis or synthesis of published material that serves to reach or imply a conclusion not stated by the sources." If anyone can get the analysis published then the argument turns to: Is the publisher reliable?

It does not even pass the Paris rule: "For example, the statement "the capital of France is Paris" needs no source, because no one is likely to object to it and we know that sources exist for it." To say that the Moon orbits the Earth needs no source. To say that the Moon orbits the Earth at a distance of 384,402 km needs a published source, if challenged. To say that the Moon orbits the Earth at a distance of 384,402 km because the Wikipedia editor has measured it using the Mount Wilson observatory needs a published source or it fails WP:PRIMARY.

However, I think your best chance of passing OR is in WP:CALC: Routine calculations. That all the machinations of JPL HORIZON are equivalent to Basic arithmetic and form an "obvious, correct, and meaningful reflection of the sources." Like 2+2=4, you would have to prove to the average Wikipedia reader that HORIZON is 100% correct and Kheider's input is also 100% accurate. In my humble opinion, of course. --RoyGoldsmith (talk) 15:16, 27 November 2017 (UTC)

One problem with your comparison is that editors do not have easy access to Mount Wilson observatory, but they do have access to Horizons and WP:CALC, especially when provided with the steps (notes) required to get the WP:CALC. Horizons has been used by other editors in featured Wikipedia articles as even the orbits of the major planets have been computed with Horizons (see:Mercury_(planet)#cite_note-horizons-5). To remove the table(s) would harm the article as it removes a useful illustrative tool. PS: As of 2017-Nov-27 the moon has a geocentric distance of 0.0026206 AU (392,040 km). -- Kheider (talk) 15:36, 27 November 2017 (UTC)

I do not think it is OR. The information is verifiable, and presenting it in a convenient table format serves well. -BatteryIncluded (talk) 18:06, 27 November 2017 (UTC)

RfC about the two tables in the Trajectory section

Should the "Observations > Trajectory" section contain the two tables "ʻOumuamua speed relative to the Sun" and "Inbound velocity at 200 AU from the Sun comparing ʻOumuamua's interstellar speed to Oort Cloud objects"? --RoyGoldsmith (talk) 19:29, 29 November 2017 (UTC)

Survey

• Oppose. These tables are solely based on the results from the public software tool Horizons by JPL with input supplied by a Wikipedia editor. Unless the results are published in a reliable source other than Wikipedia, the tables do not pass WP:NOR. --RoyGoldsmith (talk) 19:29, 29 November 2017 (UTC)

Keep. I now believe, like agr and Tom.Reding down below, that the publisher of any Horizons calculation is JPL and JPL guarantees the results. JPL may be wrong in the same sense that the New York Times (or any other reliable source) may be wrong but the problem is then with JPL, not the editor who relied on JPL. Whether the editor spent his time inputting parameters or searching the web is immaterial. --RoyGoldsmith (talk) 15:14, 2 December 2017 (UTC)

• Keep. There is a note on how to reproduce the results with JPL Horizons and so it passes Wikipedia:Verifiability and WP:CALC. To remove the table(s) would harm the article as it removes a useful illustrative tool. Horizons has been used by other editors in featured Wikipedia articles as even the orbits of the major planets have been computed with Horizons (see:Mercury_(planet)#cite_note-horizons-5). -- Kheider (talk) 19:41, 29 November 2017 (UTC)
• Keep unless there is a clear policy-based reason not to use it put forward by the wider community. Seems like an invaluable resource to me. nagualdesign 23:02, 29 November 2017 (UTC)
• Oppose. WP:OR. Calculating the sum of a set of numbers appears to be close to the limit of what is acceptable as not OR. Calculating the product, or the mean, of a set of numbers is regarded as OR. Trusting a presumably complex computer program to calculate a result is certainly OR. Maproom (talk) 14:20, 30 November 2017 (UTC)

Wikipedia:Verifiability#Access_to_sources says, "Do not reject reliable sources just because they are difficult." Out of curiosity, did you even try to verify any of the numbers using note 7? -- Kheider (talk) 15:39, 30 November 2017 (UTC)

I did not. I don't doubt that the calculation is correct, and that I could have run it. But it's still OR. Maproom (talk) 10:04, 1 December 2017 (UTC)

• Oppose. WP:CALC is the relevant policy. If you have to use a specifically programmed 3rd party tool to run the calculation, its not a routine calculation. It should be published in an RS. The wording of of calc is "Routine calculations do not count as original research, provided there is consensus among editors that the result of the calculation is obvious, correct, and a meaningful reflection of the sources." If you are relying on the tool to tell you it is correct, it is clearly not obvious. If it was obvious, you wouldn't need a tool to tell you. It may well be correct, but that's why we require RS to publish it. Only in death does duty end (talk) 18:16, 30 November 2017 (UTC)
• Keep. This is basically like looking something up in a database. You will get the same answer every time (assuming that you search for the same stuff, etc.). We have refs in multiple articles that link to a database and list the search terms you need to get to the information. WhatamIdoing (talk) 18:50, 30 November 2017 (UTC)
• Keep. Verifiable calculations using verifiable data from verifiable database. The table saves the reader time and work. BatteryIncluded (talk) 19:11, 30 November 2017 (UTC)
• Keep It's no different than using a plotting program to create a graph of a known function. No original thought is involved. Rentier (talk) 19:32, 30 November 2017 (UTC)
• Keep. The data was obtained from a reliable source and is verifiable.User-duck (talk) 19:39, 30 November 2017 (UTC)
• Keep WP:CALC does not apply here because Wikipedia editors are not performing any calculation. They are simply looking up answers in an online resource provided by an impeccable source, NASA/JPL. How the source gets its answers, via a data table look up or using a computer program is not our concern; we don't normally inquire as to the methods used by any other WP:reliable source.--agr (talk) 19:41, 30 November 2017 (UTC)
• Keep As long as all table settings are clearly identified in the reference. JPL/NASA is a reliable source. Editor isn't calculating anything themselves.   ~ Tom.Reding (talk ⋅dgaf)  19:56, 30 November 2017 (UTC)

If/when there is a published paper with distance/velocity estimates, prefer it over current table, but I see no problem with the current table until that time.   ~ Tom.Reding (talk ⋅dgaf)  20:06, 30 November 2017 (UTC)

• Keep. It can be considered a routine calculation in this specific context. Ruslik_Zero 20:01, 30 November 2017 (UTC)
• keep per reasons given by last seven editors(this had been posted at [5])--Ozzie10aaaa (talk) 21:13, 30 November 2017 (UTC)
• Keep For the purposes of Wikipedia it is a database lookup in a reliable source. I don't understand why this needs discussion. It doesn't matter if a calculation is done by a scientist with a pocket calculator or with software that scientist wrote. --mfb (talk) 01:54, 1 December 2017 (UTC)
• Uncontroversial routine calculation. Whether to include or not should be debated on the merits of this being relevant to the article or not, but this it not WP:OR. Headbomb {t · c · p · b} 02:37, 1 December 2017 (UTC)
• Kind-of a routine calculation (bot-summoned) I think WP:CALC is the relevant guideline, and I also think it applies, though it is debatable (detailed rationale to be posted below). Tigraan^{Click here to contact me} 09:28, 1 December 2017 (UTC)
• Keep since this is a verifiable calculation using a reliable calculator using reliable data it should be fine. Graeme Bartlett (talk) 00:04, 3 December 2017 (UTC)
• Oppose Regardless of the accuracy and reliability of the calculation that's WP:OR. Silvio1973 (talk) 07:03, 4 December 2017 (UTC)

Threaded discussion

• This has implications beyond this article. The results of the Horizon software are also used in Mercury_(planet)#cite_note-horizons-5 and possibly many others. Can a piece of software (an algorithm), run specifically to provide data to an article and not appearing anywhere but Wikipedia, be considered a reliable published source? --RoyGoldsmith (talk) 19:29, 29 November 2017 (UTC)
• Roy is correct. If the results of the Horizon software are deemed inadmissible then this RfC would affect other articles. I suggest that links to this RfC be posted elsewhere. I don't think this is about WP:OR though, since the facts presented in the article are provided by a published source (Horizons). The only questions are whether Horizons passes WP:RS, and/or whether using Horizons somehow contravenes WP:SYNTH. Remember, we don't always have to follow every rule to the letter. For example, WP:PRIMARY need not necessarily apply, as long as the information is reliable (and the broader topic is demonstrably notable). The goal of Wikipedia is to provide good quality, verifiable information and knowledge. nagualdesign 20:36, 29 November 2017 (UTC)
  • I've just posted directions to the RfC under Wikipedia:Village_pump_(policy) and Talk:JPL Horizons On-Line Ephemeris System. There are various usages of JH, mostly among long period comets, in Mercury (planet), Transit of Deimos from Mars, C/1980 E1, C/1999 F1, Comet Machholz and C/2017 K2 to name a few. Do you think RfC directions should be posted to these articles? --RoyGoldsmith (talk) 17:56, 30 November 2017 (UTC)
    • For Oort cloud comet articles the orbit *MUST* be computed at epochs when the comet is outside the planetary region (say epoch 1950 and epoch 2050). A generic link to the JPL Small-Body Database or the Minor Planet Center will be unreliable as it will be defined while inside the planetary system, near perihelion, as a one-size-fits-all solution. Attacking the tables in Oumuamua is much different than attacking Horizons use for orbital periods of Oort cloud comets. This probably should be discussed at Wikipedia:WikiProject Solar System. Roy, I am not sure you are aware of the damage you could do to the quality of some of Wikipedia's cometary articles. I am not confident this is the place to make and enforce a Wiki-wide policy. -- Kheider (talk) 18:19, 30 November 2017 (UTC)
      • We are an encyclopedia. We don't publish unpublished ideas, regardless of the damage done to articles about comets or anything else. The main reason why we allow routine calculations is that, if we had to because someone challenged 2+2=4, we could prove that the overwhelming majority of arithmetic textbooks and other materials say that 2+2=4. We don't have anything like that amount agreement on JPL Horizons. Thus we require a person (hopefully an astronomer or a ballistician) to say that he has run Horizon and he personally takes responsibility for the results. Kheider, are you aware of the damage you could do to all of Wikipedia itself? --RoyGoldsmith (talk) 22:18, 30 November 2017 (UTC)
        • I am not concerned as people can ask questions about how to reproduce a specific result on the talk page that JPL Horizons is used. I (and I believe others) feel the benefits of an accurate orbital period both inbound and outbound (say millions of years inbound and then 10000 years outbound) far outweigh the disadvantages of an incorrect one-size fits all solution. As far as common Oort Cloud comets are concerned, peer reviewed journals have little reason to compute barycentric orbital periods at inbound and outbound epochs. It is fair to call it more of a database lookup then original research as I did not create Horizons and anyone can verify the results if they are willing to. I do not change the values unless I am rounding off or it is a simple conversion of days to years by dividing by 365.25. Never the less, this talk page is no place to create a Wiki-wide policy rule. Concerns about Horizons should be brought up on the talk pages of the handful of pages that it is used on. -- Kheider (talk) 00:29, 1 December 2017 (UTC)
• There is no disagreement that the table is a product of calculations (WP:About Valid Routine Calculations). I don't think there is a difference if it is done with a pocket calculator or a software. The basic source is still reliable, and it is verifiable, if you go through the trouble of computing it yourself. My 2 cents. Cheers, BatteryIncluded (talk) 01:07, 30 November 2017 (UTC)
• I think that WP:CALC would apply (assuming that the formulas used & the input data are uncontested), which among other things is the reason why {{convert}} template and similar widely used calculation templates exist. Jo-Jo Eumerus (talk, contributions) 17:50, 30 November 2017 (UTC)
• The concept of using existing data in an application and the results being OR is troublesome. In this article a published image was manipulated to agree with printed info. Under the strict interpretation of OR that I have read on this talk page, it should certainly be OR! It is NOT the result of "routine calculations", I do NOT know any details of the application used, and I can NOT verify the results. I verified a few of the table entries with the JPL Horizons website. The original instructions had a small error and I updated them. Actually, I would not personally consider the use of the Horizon website "routine calculations" in most instances (the results are not "obvious"), but I do consider them "correct and a meaningful reflection of the sources", This is a contradiction in WP:CALC and I defer to editors with more experience with Wikipedia standards.User-duck (talk) 20:51, 30 November 2017 (UTC)
• Turns out the 23,000 year calculation may be OR. It is a "routine calculation" but I personally have not read that tidbit in any reference. Also, converting a distance in LD (lunar distance) units to kilometers is OR if the "convert" template is the standard for routine calculations. It was a synthesis "to reach a conclusion not stated by the sources." (WP:NOR) An additional, non-Wikipedia, reference is required to convert an LD distance in one reference to more familiar units. It is not acceptable to use the value in the Wikipedia LD article. However if a NYT reporter took WAG at the number it would now be acceptable. (I am not belittling reporters, they usually do their job very well. I just trust my own calculation more.) I will get off my soapbox now. If some of my ranting sounds ridiculous, you can appreciate how some of this discussion sounds to me.--User-duck (talk) 20:51, 30 November 2017 (UTC)
• Unless someone has more to say, I'm going to close this RfC down later today with a result of Keep. Any objections? --RoyGoldsmith (talk) 04:52, 1 December 2017 (UTC)

I'd give it another day or two. There's no rush. nagualdesign 06:26, 1 December 2017 (UTC)

OK. --RoyGoldsmith (talk) 15:15, 1 December 2017 (UTC)

• Unless I missed something about how JPL Horizons works, I strongly disagree with arguments to the effect that it is merely a database lookup. The software grinds some numbers provided by the Wikipedia editor or reader; we have no particular reason to assume this particular set of numbers was already given by a topic expert to the same software with the same results. While many databases are generated automatically and include such numbers, such databases are published and (we assume) there is someone akin to an editor who spot-checked the results for mistakes after generation (in a different step than debugging the generating program).

It seems to me that JPL, an obviously reliable source, has published Horizons as a way to access various ephemerides. It's up to JPL to ensure the calculations are correct. If the editor inputs the wrong parameters, it's like the same editor finding reliable text on the internet to paraphrase but he chooses the wrong paragraph. In this case, it's the editor's fault. But both errors should be discovered eventually.

In other words, if you assume that the calculations are correct (because JPL is a reliable source, even for software) then the editor must have made the mistake. Which happens all the time. --RoyGoldsmith (talk) 15:15, 1 December 2017 (UTC)

People incorrectly paraphrase peer reviewed papers all the time. I have seen it editing this article. ALL references are subject to review by other editors. The only options to Horizons are what output you want displayed and what dates. You are not providing numbers to the software. -- Kheider (talk) 15:26, 1 December 2017 (UTC)

So the question is whether WP:CALC applies. My view is that if something is routine for specialists of the domain (i.e. any of them would be able to perform the necessary conceptual steps without consulting a handbook even if some calls to computing power are needed), it can be considered a routine calculation. Essentially that boils down to "anything that is in the textbook (in that domain) goes". But one could easily argue that WP:CALC should be restricted for calculations that a general Wikipedia reader can check, not necessarily one particularly familiar with the article they are reading; we can assume such a reader to know basic arithmetic, but not much more. That is, of course, a subject for a much larger discussion. Tigraan^{Click here to contact me} 09:38, 1 December 2017 (UTC)

Too many details (and references) in lead.

The lead has too many details not found in the body of the article. Therefore there are too many inline references. I am thinking about moving details.User-duck (talk) 04:57, 27 November 2017 (UTC)

The lead of an article should have a simple Who, What, Where, When, How and Why. These are expanded as desired/needed in the body of the article. "6° from apex" is too complex. I have a physics degree (and some interest in astronomy) and I needed to spend way too much time looking up terms to understand the article's lead.

The details about the trajectory currently located in the lead should be in the Trajectory (and removed from the lead). Most are already repeated there but a few are not.User-duck (talk) 10:39, 29 November 2017 (UTC)

Anybody here know any Hawaiian?

The etymology in the Nomenclature section currently reads, "The name comes from Hawaiian ʻou.mua.mua 'scout', (from ʻou 'reach out for', and mua, reduplicated for emphasis​ 'first, in advance of')." When I added the ʻou.mua.mua I was copying what the reference says verbatim, but now that it's linked to Wiktionary where the word is written as ʻoumuamua I'm wondering if the full stops, or whatever they are, should be removed. Any ideas? nagualdesign 17:18, 27 November 2017 (UTC)

First bold subject of the lead

According to WP:BEGIN, the subject of the first sentence should usually match the article title. I changed it to reflect this practice and was reverted. If 1I/'Oumuamua is the preferred name, then the article title should be changed to match it, but there should first be consensus for any rename. It seems to me, there was consensus that the article title should be 'Oumuamua, not 1I/'Oumuamua. So I ask, which of the many sources cited here use the name 1I/'Oumuamua besides the MPEC listing of official designations? What justification (based on sources, not a Wikipedia editor's opinion) is there for putting it first, or even using it at all? --Robert.Allen (talk) 20:45, 27 November 2017 (UTC)

If avoiding confusion on the primary name is the goal, I see no reason this article shouldn't be renamed as 1I/'Oumuamua since 'Oumuamua and even Oumuamua will redirect here anyway. Here's a statement on correct forms: [6] "Correct forms for referring to this object are therefore: 1I; 1I/2017 U1; 1I/ʻOumuamua; and 1I/2017 U1 (ʻOumuamua)." Tom Ruen (talk) 20:56, 27 November 2017 (UTC)

As noted above, the article name follows WP:COMMONNAME. And I agree with Robert that the first sentence should match the article title. At the moment it's pretty opaque:

1I/ʻOumuamua (formally designated 1I/2017 U1; previously C/2017 U1 (PANSTARRS) and A/2017 U1) is the first known interstellar object to pass through the Solar System.

Perhaps something more prosaic is in order. The IAU says, "The object was initially classified as a comet (C/2017 U1) and later as an asteroid (A/2017 U1). [...] the new object is now officially known as 1I/2017 U1. In addition to the technical designation, the MPC also exceptionally assigned the name 'Oumuamua to the new object." If we just follow the IAU's lead, how about something like this:

ʻOumuamua (formally designated 1I/2017 U1), initially classified as a comet (C/2017 U1) and later as an asteroid (A/2017 U1), is the first known interstellar object to pass through the Solar System.

I think that's far easier to read and understand, accurately reflects the source, and also satisfies WP:COMMONNAME and WP:BEGIN, as well as MOS:INTRO ("avoid difficult-to-understand terminology and symbols.") nagualdesign 21:33, 27 November 2017 (UTC)

..The quote from the Minor Planet Centre, "Correct forms for referring to this object are therefore: 1I; 1I/2017 U1; 1I/ʻOumuamua; and 1I/2017 U1 (ʻOumuamua)." already appears in the Nomenclature section. nagualdesign 21:45, 27 November 2017 (UTC)

I think I prefer: ʻOumuamua, formally designated 1I/2017 U1 (ʻOumuamua), initially classified as comet C/2017 U1 and later as asteroid A/2017 U1 -- Kheider (talk) 21:50, 27 November 2017 (UTC)

I don't think that 1I/2017 U1 (ʻOumuamua) is a "formal designation" per se. It's a "correct form for referring to this object", in the same way that C/2017 U1 (PANSTARRS) was more of a convention (when the actual designation was simply C/2017 U1). A subtle but important difference. nagualdesign 21:54, 27 November 2017 (UTC)

Also, there doesn't seem to be any need to repeat the common name in a parenthetic expression when it has already been given earlier in the sentence. --Robert.Allen (talk) 21:01, 28 November 2017 (UTC)

How about splitting it into two sentences:

ʻOumuamua (also known as 1I/ʻOumuamua) is the first known interstellar object to pass through the Solar System. It is formally designated as 1I/2017 U1 and previously was named C/2017 U1 (PANSTARRS) and A/2017 U1.

--RoyGoldsmith (talk) 19:54, 29 November 2017 (UTC)

Personally, I think that keeping it as clean and simple as possible is a good idea. The also known as part is covered in the Nomenclature section, and I don't see the need to reproduce one possible way of referring to ʻOumuamua above all others. The most important parts would seem to be the name and designation, so I think they ought to be paramount.

One reason I chose to reproduce the sentence in my suggestion above in much the same way as the IAU is that all three designations are parenthetical. The first (current) designation includes the words "formally designated" so is absolutely unambiguous. The other two terms very clearly resemble the formal designation and are also parenthetical, which I think helps to imply that they are (or were) also formal designations without having to spell it out. It's also obvious that the only bit that has changed is before the /2017 U1, and that C probably stands for Comet and A probably stands for Asteroid. nagualdesign 20:54, 29 November 2017 (UTC)

...If we do change the opening sentence to begin, "ʻOumuamua (formally designated 1I/2017 U1)...", I think the entry in the table should also be changed to "1I/2017 U1 (ʻOumuamua)". nagualdesign 21:26, 29 November 2017 (UTC)

Argument of periheilion (link and definition)

The link for Argument of perihelion connects to "Argument_of_periapsis".

And the number given 241.7 seems to indicate day 245.2290617 of the solar year.

Shouldn't that be September 2 @ 5:29:50?

Can someone explain the number?

info@ the Ubie . com -- 72.94.230.198 (talk) 20:04, 30 November 2017 (UTC)

trajectory should be where it came from and where it is headed. there seems to be a discrepancy in the argument of periheilion sugesting it passed the sun a few days earlier.. sep 4 or so. BUT WHERE are the ORIGIN CORDINATES? (i use caps for flair and do not follow the millenial convention that they mean shouting.) -- 72.94.230.198

i think its presumptoious to call it a scout or name it after obama. it appears to be a giant footlong hotdog ( and the same color) which is extreemly freeky and if the sd220 photo is in fact the object, then it looks like a telescope. though perhaps with some artificial beings to keep it in repair. yet the time it has been out there sugests that it may simply host artificial life. we float in space here. they float in space there. you can see some of the contraversy on my page as the data is gathered. i have. not added the argument of periheilion problem yet but it looks like 241.7 is. not sept 9th.. maybe sept 4 or 5. the other matters are 'reported' here http:// the ubie . com / is-it . htm -- 72.94.230.198 (talk) 21:37, 30 November 2017 (UTC)

To properly calculate the time/date of perihelion passage you must integrate the orbit backwards. Using JPL Horizons (Soln.date: 2017-Nov-21_20:25:17) I get:

2017-Sep-09 11:47 0.25532707718556 -0.0021052 87.41886 87.41886 31338.2180 0.0234323

Which, in English, is 2017-Sep-09 11:47 UT, 0.25532707718556AU ±31338km from the Sun, going 87.4 ±0.02 km/s.

The GENERIC solution by the JPL SBDB is only a best-fit to the curve (trajectory) at epoch it is defined at. Currently JPL is defining the orbit at epoch 2017-Oct-31. -- Kheider (talk) 22:05, 30 November 2017 (UTC)

Asteroidal nature: Damocloids

The article currently states: "The lack of a coma indicates that it must have formed within the frost line of the stellar system of origin or have been in the inner region of that stellar system long enough for all ice to sublime, as may be the case with damocloids. Analysis of its spectrum indicates that the latter is likely true".[39][40]

After looking at the link damocloids, I realize the term means inactive comets (ran out of volatiles). I think that was the older (earliest) hypothesis, before they realized it is an asteroid. Since there seems to be reason to think it is instead a dense metallic rock asteroid, we should change the text on that entry. Your thoughts? BatteryIncluded (talk) 23:12, 30 November 2017 (UTC)

I have not checked the latest references or even the references used. But I think you are correct. I was waiting for the table debate to settle down. -- Kheider (talk) 23:55, 30 November 2017 (UTC)

I have changed it to read, "It is difficult to say which scenario is more likely due to the chaotic nature of small body dynamics." (Ye2017) -- Kheider (talk) 13:46, 1 December 2017 (UTC)

Sky trajectory images

• 
  Trajectory motion from Earth, 7 days of motion per marker
• 
  Trajectory seen from the Sun
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  Shown from a fixed perspective above the Solar System

I finally got around to adding an import function for drawing orbital ephemeris from JPL's HORIZONS system. I need to validate it a bit, but seems to be good. So this shows its path viewed from the earth, with 7 days of motion, and yellow spheres proportional to angular sizes. So along with the pretty annual retrograde loops, you can see the source converges near Vega in Lyra, and the destination converges in the great square of Pegasus. It was closest to earth in Orion, but unfortunately before discovery. Tom Ruen (talk) 08:10, 1 December 2017 (UTC)

Nice diagram, and it must have taken a lot of work, but it is very easily misunderstood as its actual trajectory, and gives the impression of orbiting stellar objects. It could be a source of interpretational problems. BatteryIncluded (talk) 15:37, 1 December 2017 (UTC)

I like it. Just need to describe it as Oumuamua's motion across the sky. -- Kheider (talk) 19:42, 1 December 2017 (UTC)

Here's another quick one (unlabeled), motion seen from the sun although an impossible view, a simpler motion. Tom Ruen (talk) 16:10, 1 December 2017 (UTC)

Here's another shown from a fixed perspective above the solar system so the hyperbola focus is more clearly on the sun. Tom Ruen (talk) 20:58, 1 December 2017 (UTC)

The third one looks good. I'm glad that one was chosen over the others. I might tinker with it a little if you don't mind, Tom? nagualdesign 04:15, 2 December 2017 (UTC)

Sure. I can remake things differently as well. But I don't know where they are best in the article either. Where images are now don't really make sense. Tom Ruen (talk) 04:19, 2 December 2017 (UTC)

@Tomruen: Could you tell me on what date ʻOumuamua passed above the ecliptic and when it passed back through? nagualdesign 22:01, 2 December 2017 (UTC)

I've thought about visualization changes for above/below the ecliptic. It's easy to check the data by the declination sign. [7] Tom Ruen (talk) 23:01, 2 December 2017 (UTC)

Date__(UT)__HR:MN     R.A._(ICRF/J2000.0)_DEC  APmag            delta      deldot    S-O-T /r    S-T-O
2017-Sep-06 00:00     11 12 02.86 +00 05 24.6  21.05 1.25616963759190 -22.7910047   7.2618 /T  26.4403
2017-Sep-06 12:00     11 09 28.79 -00 22 10.4  20.99 1.24925834878085 -25.0964034   7.0888 /T  26.5352
And
2017-Oct-16 00:00     03 34 03.93 -00 28 31.6  19.76 0.16746168064530  15.8239045 146.1884 /L  29.1155
2017-Oct-16 12:00     03 11 51.39 +00 08 27.7  19.70 0.17285802437473  21.4683896 152.0566 /L  23.9058

Okay, thanks Tom. I found the videos and images online a little confusing. The ESO video appears to show ʻOumuamua approaching from beneath the ecliptic, but Scott Manley's video looks like it approached from above. Something akin to the Hollow-Face illusion going on, I guess.

So am I correct in thinking that it approached from above, dipped down between the Sun and the orbit of Mercury, then came back up between the orbits of Earth and Mars? nagualdesign 23:09, 2 December 2017 (UTC)

...Assuming that that was the case, I've uploaded a new version of the image. Let me know what you think. If you prefer, I can remove the glow from the Sun, or any other changes. nagualdesign 23:32, 2 December 2017 (UTC)

Its very nice as-is. Mine was purely computed except the labels. The under/over orbit lines are very helpful, so you don't need to know exactly where it crosses the ecliptic. Tom Ruen (talk) 01:47, 3 December 2017 (UTC)

Glad you like it, and that it's accurate. One small matter that irks me is the positions of the planets. Given the timescale involved (13+ weeks) Mercury would have made slightly more than one complete orbit and the Earth would have made a quarter orbit, which begs the question as to what date the planets were in those positions? It might me helpful if you add that information to the image file description (the caption in the article is fine as it is). Thanks, Tom. nagualdesign 16:18, 3 December 2017 (UTC)

Yes, it is confusing. The planets are positioned at perihelion. There's no clear right answer unless we don't draw planets OR label planets with a date, or possibly multiple dates. My program currently only selects a single object to draw a tracking path, but I could make multiple images, tracking different objects, if you wanted to rework some of them into one diagram. But since I don't save exact viewing locations, I'd have to tweak something approximately the same, and you might need to rework your version from scratch if not close enough. Tom Ruen (talk) 19:24, 3 December 2017 (UTC)

For clarity specifically, the perihelion positions could be drawn differently, equal circles, with smaller circles for the other dates of 'Oumuamua. And maybe showing a second earth position dated and labeled with that earth. Tom Ruen (talk) 04:05, 4 December 2017 (UTC)

I would have guessed that the planets are positioned at perihelion. I don't think there's a better way to draw it. Showing the direction of the planets' orbits helps to show that we're looking at the Solar System from 'above'. And the image is primarily an overview of ʻOumuamua's trajectory, so adding extraneous details would just make the diagram unnecessarily busy. S'all good. And now that I look I see that you'd already edited the file description long before I asked! Great minds think alike. nagualdesign 04:19, 4 December 2017 (UTC)

Just to not open another section, here is a new article on the ongoing efforts to figure its place of origin and systems it may have flown by: [8]. Cheers, BatteryIncluded (talk) 00:01, 3 December 2017 (UTC)

How close did it get to Earth?

How close did it get to Earth and what was its speed (relative to Earth) then? What would have been the consequences if it hit the Earth, whether sideways or (probably worse) head on?

From http://www.sciencemag.org/news/2017/11/updated-first-time-astronomers-are-tracking-distant-visitor-streaking-through-our-solar

On 14 October, it made its closest pass by Earth, at 60 times the distance to the moon.

At Oumuamua's closest approach to Earth it was 0.16163 AU (24,180,000 km; 15,024,000 mi) ±6000km away traveling 60.2 km/s with respect to Earth. Given the angles involved it is not moving much faster than typical Oort cloud objects with respect to the Earth. At 2017-Oct-14 17:51 UT, Earth was orbiting the Sun at 29.87 km/s and Oumuamua was traveling 47.89 km/s with respect to the Sun. So by adding those two speeds you could theorize a perfect head-on at 78 km/s. -- Kheider (talk) 18:57, 1 December 2017 (UTC)

New Paper: 1I/'Oumuamua is tumbling

1I/'Oumuamua is tumbling Wesley C. Fraser, Petr Pravec, Alan Fitzsimmons, Pedro Lacerda, Michele T. Bannister, Colin Snodgrass, Igor Smoli'c (Submitted on 30 Nov 2017)

Summary: The discovery of 1I/2017 U1 ('Oumuamua) has provided the first glimpse of a planetesimal born in another planetary system. This interloper exhibits a variable colour, within a range that is broadly consistent with local small bodies such as the P/D type asteroids, Jupiter Trojans, and dynamically excited Kuiper Belt Objects. 1I/'Oumuamua appears unusually elongated in shape, with an axial ratio exceeding 5:1. Rotation period estimates are inconsistent and varied, with reported values between 6.9 and 8.3 hours. Here we analyse all reliable optical photometry reported to date. No single rotation period can explain the exhibited brightness variations. Rather, 1I/'Oumuamua appears to be in an excited rotational state undergoing Non-Principal Axis (NPA) rotation, or tumbling. A satisfactory solution has apparent lightcurve frequencies of 0.135 and 0.126 hr-1 and implies a longest-to-shortest axis ratio of 5:1, though the available data are insufficient to uniquely constrain the true frequencies and shape. Assuming a body that responds to NPA rotation in a similar manner to Solar System asteroids and comets, the timescale to damp 1I/'Oumuamua's tumbling is at least a billion years. 1I/'Oumuamua was likely set tumbling within its parent planetary system, and will remain tumbling well after it has left ours.

Maybe Wikipedia needs a new article tumbling (rigid body) for chaotic rotations. This also applies for a couple moons of Pluto and Hyperion (moon) of Saturn. Tom Ruen (talk) 06:14, 3 December 2017 (UTC)