PDA

View Full Version : What can dissolve in Titan's lakes? Results of a lab simulation...



Colin Robinson
2014-Mar-14, 07:40 AM
Titan is known to have large carbonaceous molecules in its atmosphere, and lakes of liquid on its surface.

An important question is, how much of the carbonaceous material formed in the atmosphere is soluble in the liquid of the lakes? Liquid ethane and methane are known to be relatively weak solvents, distinctly weaker than water.

A very recent laboratory simulation seems to show that large molecules formed in the atmosphere can indeed dissolve in liquid ethane at the surface, forming a complex "soup" of carbon compounds ... The lab simulation is somewhat like the Miller-Urey experiment, but designed to mimic conditions on Titan rather than ancient Earth.

Saturn's largest moon home to prebiotic "soup" (http://www.rsc.org/chemistryworld/2014/03/saturn-moon-titan-prebiotic-soup)

marsbug
2014-Mar-14, 01:28 PM
Its important to note that the experiment used isopentane as an intermediate step. Isopentane is similar in many ways to ethane, but it's freezing point is warmer than titans surface temperature (-179 deg C for titan, isopentane freezes at -169 deg C, ethan and methane about -182 deg C). However if there is one pathway to get large molecules to be soluble in ethane there will be others. Nature is nothing if not inventive and systems with complex patterns/behavoir occur in all sorts of unexpected places. Also, bear in mind we don't know what the exact composition of titans lakes is. It could be a mixture of many things, with properties that don't quite match any of it's constituents. this is encouraging, but just the latest step on along road to understanding the goo-ology of Titan.

And why no waves on them? Have any waves been detected yet on Titans lakes?

Colin Robinson
2014-Mar-14, 07:42 PM
Its important to note that the experiment used isopentane as an intermediate step. Isopentane is similar in many ways to ethane, but it's freezing point is warmer than titans surface temperature (-179 deg C for titan, isopentane freezes at -169 deg C, ethan and methane about -182 deg C). The article in Chemistry World doesn't explain why the experiment was done that way. Perhaps it was intended to simulate the interaction of different sized carbon compounds in the atmosphere, as they condense in the upper regions and descend to the surface?


However if there is one pathway to get large molecules to be soluble in ethane there will be others. Nature is nothing if not inventive and systems with complex patterns/behavoir occur in all sorts of unexpected places. Also, bear in mind we don't know what the exact composition of titans lakes is. It could be a mixture of many things, with properties that don't quite match any of it's constituents. this is encouraging, but just the latest step on along road to understanding the goo-ology of Titan.
Life is a variation on the theme of goo.


And why no waves on them? Have any waves been detected yet on Titans lakes?
Maybe the soup is too thick for waves?

marsbug
2014-Mar-15, 01:30 PM
I take the paper as being a 'proof of principle'. A sort of: 'Look, we can get big molecules to dissolve in ethane under X circumstances, so there may well be other (more titan-like) circumstances that will also let things dissolve in it' Given the massive number of organic molecules present in titans atmosphere I'd be stunned if isopentane wasn't present in some amount - it's a fairly simple molecule. I'll also be surprised if the isopentane was the only route to get big molecule to dissolve.

What other variations on the theme of goo are there, and will titan tell us?

ravens_cry
2014-Mar-15, 03:37 PM
Time to give Huygens a buddy and go and find out, yes?

marsbug
2014-Mar-15, 07:23 PM
Long since that time. The lakes are already predicted to contain important prebiotic molecules like HCN. But it's a big challenge, and no-ones stepping up to the plate. Much easier to explore Mars!

publiusr
2014-Mar-15, 07:24 PM
Now to get a BP station up there...

marsbug
2014-Mar-15, 08:00 PM
No joke, the things we could learn through an all out scientific survey of Titan, about low temperature organic chemistry, could make a lot of money. Or not, we'll never know until we look. But I wonder if BP could be made interested enough to fund some Titan laboratory studies. They don't just 'do' oil, BP has it's fingers in almost every area of organic chemistry in some form or other; Advanced materials, plastics, lubricants, nanoparticles, surface science, fluid dynamics... I don't know if they'd pay for a Titan mission but they'd certainly be reading the GC-MS results.....

loglo
2014-Mar-19, 12:26 PM
Its important to note that the experiment used isopentane as an intermediate step. Isopentane is similar in many ways to ethane, but it's freezing point is warmer than titans surface temperature (-179 deg C for titan, isopentane freezes at -169 deg C, ethan and methane about -182 deg C). However if there is one pathway to get large molecules to be soluble in ethane there will be others. Nature is nothing if not inventive and systems with complex patterns/behavoir occur in all sorts of unexpected places. Also, bear in mind we don't know what the exact composition of titans lakes is. It could be a mixture of many things, with properties that don't quite match any of it's constituents. this is encouraging, but just the latest step on along road to understanding the goo-ology of Titan.

And why no waves on them? Have any waves been detected yet on Titans lakes?

A timely question. See http://www.universetoday.com/110425/surfs-up-on-titan-cassini-may-have-spotted-waves-in-titans-seas/

marsbug
2014-Mar-20, 01:30 PM
Waves 2 cm tall are themselves a mystery! Titan has 1/7 of Earth gravity, and a thicker atmosphere. If the waves only get 2 cm big we're still missing something! And, to quote the universe today article:


Then again, wave action isn’t the only possible answer. Similar varied specular highlights could also be caused by a wet surface — like a methane mud flat.

We really need a Titan polar lander.

marsbug
2014-Mar-27, 09:35 AM
Reading this abstract (http://www.hou.usra.edu/meetings/lpsc2014/pdf/1841.pdf), it seems that one answer to the question 'what can dissolve in Titans lakes' might be 'whole islands'.