Printable Version of Topic

Posted by: MichaelT Dec 13 2006, 08:21 PM

I just read an interesting article on "Episodic outgassing as the origin of atmospheric methane on Titan" (Tobie et al., 2006. Nature, Vol. 440, No. 4497, 61-64). It describes the evolution of Titan's interior and the resulting release of methane (3 episodes). The second episode of outgassing is supposed to have taken place 2-2.5 Gyr ago due to core convection. Prior to that Titan's core heated up due to diffusive heating which finally led to a thinning of the outer methane clathrate layer and subsequent release of methane.

Is the diffusive heating a differentiation processes within the core? What is it exactly?
It would be great if someone could help me understand it.

Michael

Posted by: AlexBlackwell Dec 13 2006, 11:39 PM

MichaelT, did you get a chance to read the online http://www.nature.com/nature/journal/v440/n7080/suppinfo/nature04497.html to the paper?

Posted by: MichaelT Dec 14 2006, 10:24 AM

Thanks Alex!
I had not seen that information. But, when I read "thermal diffusion" I suddenly realized what "diffusive heating" is. Should have been quite obvious actually.
So it is simply heating of the core mainly by radiogenic heat. As long as convection has not set in, heat transport happens only via diffusion. When the core reaches a critical temperature convection sets in and transports heat much more efficiently towards the surface. Correct?

Michael

Posted by: AlexBlackwell Dec 14 2006, 11:32 PM

Are you sure you're not checking just to see if I know?

Posted by: MichaelT Dec 15 2006, 09:37 AM

Ok, ok, I admit

Thanks again,
Michael