Talk:Triton (moon)
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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)
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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 (http://ssd.jpl.nasa.gov/) 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)
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)
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] (http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1989A%26A...219L..23C&data_type=PDF_HIGH&type=PRINTER&filetype=.pdf). Triton will be around either 1.8 or 3.6 Gyr, depending on its orbital state. hike395 15:39, 27 Feb 2005 (UTC)
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] (http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WGF-49W6NPN-1&_coverDate=12%2F31%2F2003&_alid=259406681&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=6821&_sort=d&view=c&_acct=C000014439&_version=1&_urlVersion=0&_userid=209810&md5=0924edad445e490f06e1643105d73dcb)] (Specifically about some evidence for an ocean under Triton). Or this abstract: [[3] (http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001AGUFM.U12B..02S&db_key=PHY)] Or this BBC article: [[4] (http://newsimg.bbc.co.uk/1/hi/sci/tech/2290005.stm)] 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)