Hi Roger. Here is Lowell’s reply to your post. Take Care…Don in creepy town

Don,

Thanks for posting that response to earthwaves. I can read it but not post from here. Anyway, you can post this response to Roger, if you would like.

Size is in the eye of the beholder. When I refer to large convection cells, I refer to those which used to be thought to churn the entire mantle - tomographic imaging does not really support any of this size. Some apparently do reach several hundred to a thousand km, however.

There have been a number of good articles on the subject in the past 20 years. I would suggest, if you have access checking out some of the Dziewonski and Woodward (I think that is the right second author) papers in the Journal of Geophysical Research, if you have access to that journal.

They are always changing and may even be on the web by now. The pictures are colorful and quite interesting in detail as well. And, yes, Roger, we agree that whatever (and however large) convection cells do exist, they are caused by a combination of differential heating and stirring. Tides are not known (or thought) to have any significant effect by most authors.