Talk:Triton (moon)/Archive 1
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[edit] I dispute the sentence
One day it will approach Neptune's Roche limit and it will be torn apart by tidal forces, forming a spectacular planetary ring system much like Saturn's.
The zero-strength Roche limit for Triton is only 28600 km, by my quick computation. This is only ~4000 km above Neptune cloud tops. And, Triton won't break up at the Roche limit --- it has some internal strength. So, it seems likely to me that Triton will eventually run into Neptune's atmosphere, get atomspheric drag, and smash into Neptune: the mother of all impact events.
Am I off-base here? Comments? -- hike395 18:05, 17 Apr 2004 (UTC)
Yes, you are a bit off base. For a body the size and mass of triton atmospheric drag is irrelevant. It will definetly help in breaking loose the upper layers of triton, but over a long period of time and only as a bonus to tidal breaking. The "impact" will probably last thousands of years until triton is completly destroyed. During that time Neptune's atmosphere will be hot, probably red-hot. It will be quite a show, but it won't be a huge impact event.
Rnbc -- 2005 December 20
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- Ain't both tidal braking and (more influental at later stages) atmospheric drag effects rise exponentially? If so, even a large body like Triton will deorbit relatively quickly (a few years to few tens of years once drag becomes observable (bolide phase)).
[edit] Tilt isn't Obliquity
There is a widespread error that seems to have propagated slowly through the various Wikipedias: whoever first entered the physical characteristics of the various moons misunderstood the meaning of "Tilt" in the JPL Solar System Dynamics tables (there is no doubt that this is where the figures came from, as the digits are/were identical).
A careful reading of the aforementioned pages reveals the Tilt is the angle between the local Laplace plane and the primary's equatorial plane. It has nothing to do with the moon's Obliquity (which would be the angle between its axis of rotation and the normal to its orbital plane). By definition, any moon in synchronous rotation has an obliquity of zero, which is why I twigged to this mistake the first time.
This is why I've been deleting these entries as I go. (I just hope I won't have to repeat this comment for every moon article...)
Urhixidur 04:37, 2004 Jul 17 (UTC)
- Please don't delete the row itself from the table; it's part of the standard template over at Wikipedia:WikiProject Astronomical Objects. Instead, either put the correct value in there, or leave the data cell blank. Bryan 04:54, 17 Jul 2004 (UTC)
[edit] Tidal Heating?
Whoever wrote about tidal heating seems off base. Triton's eccentricity is zilch, there are no other major moons around, and its orbit's tilt with respect to the local Laplace plane is a mere 0.511°. Any tidal heating is only going to come from the very small libration this tilt introduces. Sources, please?
Urhixidur 15:24, 2004 Aug 20 (UTC)
- Whoops... sorry. I am a "fan" of astronomy, but by no means an expert. I had simply been surprised that the article had no mention of the fact that Triton is sometimes put forward as a "candidate" for life outside of Earth. I knew that tidal heating is often mentioned in regard to Europa, and this article itself does in fact mention tidal heating, so I made a rather uneducated assumption. As I now reread the sentence where tidal heating is mentioned in this article, I understand it to mean that such heating may have occured long ago in Triton's history, shortly after its capture by Neptune.
- Perhaps a whole section isn't even appropriate for this topic? A single sentence somewhere in the main flow of the article might be better, as the possibility of life on Neptune isn't actually considered to be all that likely. AdmN 04:08, 21 Aug 2004 (UTC)
[edit] Only 100 million years left for Triton?
On June 13, 2004, 80.202.77.137 inserted the following statement into the Triton page:
Due to its retrograde motion, Triton's already-close orbit is slowly decaying further from tidal interactions, and it is predicted that in about 100 million years, it will be smashed by Neptunes gravitational field and end up as a gigantic ring around its mother planet.
100 million years is a pretty small time into the future in terms of postualted solar system history.
Hike395, earlier on, gave the Roche limit of Triton at 28600 km.
Check the Mean Orbital Radii of the following moons of Uranus:
Miranda - 129,390 km Ariel - 191,020 km Umbriel - 266,300 km Titania - 435,910 km Oberon - 583,520 km
The Mean Orbital Radius of Triton is now 354,800 km.
Can anyone provide links or references, to the exact figure of only a hundred million years left, for Triton?
-Edital Edital ZZ:ZZ, 2005 Feb 26 (UTC)
- It's not right. See the paper [1]. Triton will be around either 1.8 or 3.6 Gyr, depending on its orbital state. hike395 15:39, 27 Feb 2005 (UTC)
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- The mentioned paper is based old data, prior to the Voyager probe. Some assumptions are incorrect, some data is missing, the method might not be the most accurate by present standards. I've found far more mentions ranging from 10^7 to 10^8 years. I think this needs a specialist to come in our help. Rnbc 00:42, 28 December 2005 (UTC)
[edit] Potential for life
This caption looks wildly speculative. Suggested by who? Any reference? Do we need speculations, especially in a fact article like this? Secondly, I'm not sure that Neptune's magnetic field is very dangerous. There are not much charged particles available and the magnetic field is not nearly as powerful as Jupiter's magnetic field. Please correct if I'm wrong. Thirdly, Triton is way too cold to support liquid water. There may be (and probably are) nitrogen etc. liquids, but not water. --Jyril 22:11, Mar 11, 2005 (UTC)
There has been a great deal of speculation lately about subsurface oceans of water, or a mixture of water or something else, in many of the satellites in the outer solar system. We suspect there probably is one under the surface of Europa from tidal heating; Galileo found evidence for an ocean in Callisto's interior as well. Typically, these oceans would be heated from tidal heating, or natural radioactivity from within, not from the Sun. For Triton and other bodies very far from the Sun, it is speculated that these would not be pure water oceans, but, for example, water mixed with ammonia, lowering the melting point. For example, see: [[2]] (Specifically about some evidence for an ocean under Triton). Or this abstract: [[3]] Or this BBC article: [[4]] And the reasoning goes, where there is liquid water, there could be life. As far as the magnetic field goes... I don't know how hostile Triton's surface is in that regard. Any life that exists now on Triton would be well underground, presumably shielded by kilometers of ice. However, it may have had implications for life if Triton was captured by Neptune, an event which could heat up the moon so much that it had surface oceans. The Reflection 06:13, 23 Mar 2005 (UTC)
Life on Earth is based on carbon, but on Triton, life could be based on silicates.
I removed this sentence, because it looks way too speculative. Please add it back if you have a credible source for this.--Jyril 17:59, 29 December 2005 (UTC)
- The Portuguese sentence said that other scientific ideas say that although Earth's life is based on carbon, Triton's life, could be based on silicate compounds. Given that this very speculative, it is best to keep that out. I am just the translator...--Adam (talk) 18:19, 29 December 2005 (UTC)
[edit] adjectival form
The adj. form 'Tritonic' in the OED suggests the demonym would be Tritonian. The n can be seen to be part of the root in the taxonomic family Tritonidæ as well. This is confirmed in Liddell & Scott's with the Greek genitive trītōnos and plural trītōnes. kwami 2005 June 30 07:59 (UTC)
[edit] improvements from the Portuguese version
I will add some information from the Portuguese featured article: pt:Tritão (satélite)--Adam (talk) 16:36, 28 December 2005 (UTC)
- I have made all the changes. Go ahead and review and correct. Perhaps this article can be brought up to featured status as the Portuguese one was.--Adam (talk) 14:06, 29 December 2005 (UTC)
[edit] Pronunciation
How is trye'-tun intended to be pronounced? To me it looks like it's saying ['trajtun] or even ['trajtu:n]. What forms of English are there that actuall articulate the second vowel? As far as I know both Brits and Americans would pronounce the second syllable with just a syllabic [n].
Peter Isotalo 11:22, 31 December 2005 (UTC)
- That's why I prefer IPA, because it is not ambiguous. Of course, if the pronunciation depends on the form of English you're using, it is harder to justify one pronunciation over the other on a culturally neutral subject as this moon.--Jyril 12:00, 31 December 2005 (UTC)
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- We've added schwa to the spelling pronunciations, so I changed that. Also linking to the key though the satellite template. kwami 19:10, 31 December 2005 (UTC)
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- That would be fine, though it's a theoretical claim with a phonemic notation. I didn't want to make the transcription too narow. There's no phonemic distinction between schwa-C and C as far as I know, so people would automatically make the /n/ syllabic. The IPA-for-English usage in Wikipedia adds lots of schwas that I would never use in transcribing my own pronunciation, and I was trying to maintain some consistancy with that, but go ahead make it syllabic if you like. kwami 16:44, 1 January 2006 (UTC)
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- I think some Caribbean dialects might, but I don't know for sure. kwami 17:31, 1 January 2006 (UTC)
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[edit] 11% ammonium in Earth's moon?
The article states that 'The Earth's Moon contains approximately 11% ammonium'. I have never heard about that before, and there is no mention about it on the Moon page. What is the source of that information, and is it correct? I find that hard to believe, unless it is buried somewhere below the surface, because I guess it would evaporate quickly. (Oliver)
- Sorry- incorrect translation (From Portuguese, where much of the text came from)- I was sleepy when I did it. I will take care of it. That sentence should read: Triton is very bright, reflecting 60-95 % of the sunlight that reaches it while Earth's moon reflects only 11%. I don't even remember putting in that it contained ammonium, but in short I will replace that sentence.--Adam (talk) 03:40, 11 January 2006 (UTC)
I think the word you were looking for was "albedo"?--Syd Henderson 21:47, 17 July 2006 (UTC)
[edit] Unreferenced article
I think this article is already a pretty good one, but it is almost devoid of references. Please provide them.--Jyril 20:45, 24 February 2006 (UTC)
On the other hand, is it really necessary to ask for a citation of the comparison of Triton's surface area compared to Earth? You can calculate this by hand in a few seconds if you know Triton's and Earth's radii.--Syd Henderson 21:41, 17 July 2006 (UTC)
[edit] Tidying up the "History of observation and exploration" section
I've just been tidying up the "History of observation and exploration" section, and as I'm not an expert in this area, there are a couple of things that the experts here might want to review:
The original text read: "Lassell started to search for the satellites and discovered Triton eight days after beginning to search, on 10 October, 1846, only 17 days after having discovered the planet Neptune. Even though Neptune has rings, they were so faint and dark that what Lassell saw was probably an illusion. " implying that Lassell claimed to have observed rings, but failing to state this. I have taken the liberty of stating the implication, since it clearly reads better, but if this is factually incorrect, than please remove.
I've expanded "and it is very inclined" (the orbit) to try and make it a bit clearer, however I fear I may still have failed to be sufficiently accurate in my terminology. Again expert review would be appreciated.
Have removed "and it was decided to overfly the moon even if it affected the trajectory of Voyager 2." as it's irrelevant.
Couldn't make anything of "Even though the properties of Triton had been defined almost correctly in the 19th Century, little was known about Triton until Voyager 2 arrived at the end of the 20th Century." - if anyone else wants to have a go or feels confident enough simply to delete it, be my guest.
"In the 1990s, different observations from Earth were made of the limb of Triton using the occultation of stars by Triton." Is 'limb' correct terminology or a mistranslation, and if the former, would an explanation be in order? --Brianpie 22:02, 30 April 2006 (UTC)
[edit] Re: Citations needed
Greetings. The text
Triton's surface area is 23 million km² (4.5% of Earth, or 15.5% of Earth's land area).
has been labelled "citation needed".
Known facts:
- The surface area of Earth is known to be 5.10×10¹⁴ m².
- Of Earth's surface area 29.2% is land (often approximated as ¼ = 25%).
- Triton's mean diameter is known to be 2706.8±1.8 km.
- The value for Triton's surface area quoted in the table is 2.3018×10¹³ m².
From these facts we can easily compute
- 4.5% of "the surface area of Earth" equals 2.2950×10¹³ m².
- 15.5% of "Earth's land area" equals 2.30826×10¹³ m².
What citation would be required?
- Wikiborg 21:55, 21 August 2006 (UTC)
