Talk:Tholin

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I've read elsewhere that tholin has a sticky consistency and is dark red in colour - true?— Preceding unsigned comment added by 194.138.39.53 (talk) 06:06, 14 June 2004‎

Yes -- Ŭalabio 05:35, 2005 Jan 15 (UTC)

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It would be handy if someone with relevant knowledge could describe the chemistry of tholins in more detail in the article. The line about "not forming naturally on modern-day earth" suggests that they're unstable at STP, and their building blocks suggest very interesting chemistry, but the article doesn't provide much further information beyond what the source materials are. --Christopher Thomas 05:47, 30 Apr 2005 (UTC)

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Just to head off anyone who thinks the article is correct when naming the NICMOS. Here's the official page.[1]24.6.198.12 (talk) 06:14, 14 February 2008 (UTC)

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Structure please!!Oblivioid (talk) 04:54, 15 September 2008 (UTC)

Yes it definitely needs to be structured. This should not be in the beginning: "Tholins have also been detected in the solar system of an eight-million-year-old star known as HR 4796A using the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) aboard the Hubble Space Telescope. HR 4796A is 220 light years from Earth.[1]" —Preceding unsigned comment added by 80.250.238.104 (talk) 17:54, 19 November 2008 (UTC)

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Some examples showing chemical composition would be nice. Kevink707 (talk) 15:43, 5 February 2009 (UTC)

Article is not self-consistent

The lead says "Tholin ... is a heteropolymer molecule", which makes it sound like it's a specific compound, but later in the article it says "it is not a specific compound but is a term generally used to describe the reddish, organic component of planetary surfaces." One of these needs to be corrected or clarified.

Nathaniel Virgo (talk) 21:31, 23 July 2011 (UTC)

With all due respect, that is common in Wikipedia articles. :) Feel free to edit.

In truth, most of our characterization of tholins is theoretical and based on long-distance observation. I'm jonesing for a sample-return mission that brings some tholin back for examination. Kortoso (talk) 01:42, 4 January 2019 (UTC)

Swap greek definition

"Gk ϴὸλος, muddy; but also ϴoλòς, vault or dome" -> author got the defintions wrong. The correct terms are: "Gk ϴὸλος, vault or dome; but also ϴoλòς, muddy/blurred". https://translate.google.com/#el/en/%CE%B8%CE%BF%CE%BB%CF%8C%CF%82 https://el.wiktionary.org/wiki/%CE%B8%CF%8C%CE%BB%CE%BF%CF%82

Do natural tholins actually exist?

Some researchers in the field, e.g. Sarah Horst at Johns Hopkins, have expressed strong views that tholins are simply a laboratory-created set of chemicals. They feel that the idea they actually exist in space is an analogy or a theory. The current text of this article does not mention this, and strongly implies that tholins are a real component of planetary bodies. Should we note that this is not a universally-held view? Fcrary (talk) 23:15, 18 December 2017 (UTC)

The Huygens lander investigated the surface chemistry of Titan, and confirmed a wide variety of organic compounds [2]. It also detected them on the atmosphere of Titan. I think spectroscopy was obtained from Europa and other Saturn moons, and it also indicates tholins on their surfaces. [3]. So, tholins on Titan were confirmed in-situ, and spectroscopy of other icy bodies (flybys/orbiters) strongly suggest the same. Another recent in-situ analysis was that of Philae and Rosetta of comet Gerasimenko, and it did reveal an organic-rich crust. I hope this helps. BatteryIncluded (talk) 00:14, 19 December 2017 (UTC)

I looked at a couple of research articles authored by Sarah Horst (2011, 2012), and she seems all on board with tholins on icy bodies and on Titan. She also wrote they are the likely precursors of prebiotic chemistry. -BatteryIncluded (talk) 00:36, 19 December 2017 (UTC)

It's a subtle point, but the issue is not over the presence of complex organics on Titan or other solar system bodies. That's very definitely an established fact. The issue (and I've heard Horst's speech on the subject in person) is whether or not those complex organics are the same ones as people produce in laboratories. The mix of chemicals is noticeably different if they are produced by UV rather than electric discharge, or if a different mixture of nitrogen and methane used in the experiment. The data from other places in the solar system isn't good enough to distinguish this, so I think some purists would rather reserve the term, "tholin" for the stuff we have in the lab, know what it's made of and how it was made. Fcrary (talk) 20:59, 19 December 2017 (UTC)

Tholin is just a generic informal name for a wide variety of organic compounds formed by solar ultraviolet irradiation or cosmic rays. I am sure they differ in composition, molecular weight and concentrations, whether produced in the lab or on comets, asteroids or icy moons. As Sarah H. points out,[4] "most frequently used synonyms for tholin are “gunk”, “brown gunk”, and “complex organic gunk”. But I guess we could make a distinction between lab tholins and natural tholins. -BatteryIncluded (talk) 01:09, 20 December 2017 (UTC)

I'd be fine with simply saying, "Some researchers in the field prefer a narrowed definition of tholins, for example S. Horst wrote: Personally, I try to use the word “tholins” only when describing the laboratory-produced samples, in part because we do not really know yet how similar the material we produce in the lab is to the material found on places like Titan or Triton (or Pluto!).[5]" I'd just like to see a statement that the usage isn't universally agreed up. I don't think the quote is a problem as far as using a primary source is concerned (a primary source stating a personal opinion is ok.) By the way, do you know how to put the umlaut over the o in her name? — Preceding unsigned comment added by Fcrary (talk • contribs) 19:42, 20 December 2017 (UTC)

"energetic particles"?

What does that mean exactly? And what role do these "energetic particles" play in the chemical reactions exactly? RhinoMind (talk) 16:18, 21 December 2017 (UTC)

Cosmic ray particles, gamma ray particles, cosmic radiation, ionizing radiation, etc. are capable of bumping atomic (carbon, nitrogen, hydrogen...) electrons to higher level and create new chemical bonds with other atoms. BatteryIncluded (talk) 17:25, 21 December 2017 (UTC)

Or simply breaking the chemical bonds, after which the fragments recombine. That's where the cyanogens on Titan come from. Splitting CH4 and N2 and having the fragments produce HCNH. But the text of the article looks clear enough about this.Fcrary (talk) 19:54, 21 December 2017 (UTC)

Thanks. I couldn't find any of that mentioned anywhere. Shouldn't we put some of this info in the article then? With a few wiki-links? (Cosmic radiation is a good idea I think) RhinoMind (talk) 20:44, 21 December 2017 (UTC)

I'm seeing a description like this (with links to articles on "dissociation" and "ionization") in the second paragraph of the "Formation" section. But if you want to expand on that, I wouldn't complain.Fcrary (talk) 21:13, 21 December 2017 (UTC)