Comments on Mike Brown's Planets: Fog! Titan! Titan Fog! (and a peer review experime...

Congatulations! Interesting and exciting experimen...

2009-12-05T16:21:21.138-08:00

Congatulations! Interesting and exciting experiment.

Are we sure ethane is a one way street? Someone a...

2009-09-01T07:20:01.448-07:00

Are we sure ethane is a one way street?

Someone already suggested a chemical rxn that would break it down, sounds implausible/ineffective at those temperatures but I don't know that it is. But in any case those aren't pools of pure ethane, there has to be methane dissolved in it how much difference could that make?

-M

Quick question and observation. From what I last ...

2009-08-31T08:10:28.942-07:00

Quick question and observation. From what I last read the surface temperature of Titan is roughly -290F, yet methane freezes at roughly -296F. Isn't that a little close, wouldn't this be more snow like, or did I miss something. If you cool things down a little are you not getting closer to that freezing number?

Do you need to explicitly rule out geothermal meth...

2009-08-29T01:50:07.257-07:00

Do you need to explicitly rule out geothermal methane (or is that just a special case of methane pools, albeit with a rather different, and no longer so 'hydrological', cycle)? Being hotter, it might make mist more easily.

I found it hard to understand why you needed three filters to do the initial identification. What does 5μm add that the surface filter doesn't, and vice versa? It looks as if the answer is that nearly everything (but not quite everything) is dark at the surface at 5μm whereas there's a lot of greyness in the surface filter, but I wasn't quite sure. That might just be me, and the intended audience not have any difficulty.

I also didn't understand (not having followed up the references) what you mean by 'identical' synthetic filters in the first para of Section 2. Does it refer to the way the wavelengths are weighted?

I take it there aren't any other possible volatiles? I looked around for information on C2H2, C2H4, HCN, etc and they all seemed as involatile as ethane. Couldn't find data on CH2NH but it seems implausible on the face of it.

Hope that helps - not being a scientist I find it hard to know when something is a convention that I'm not familiar with.

In principle, any paper on Arxiv is open for review - does that happen in practice?

OK. Resubmitted with a smaller fig 1 and the typos...

2009-08-28T14:07:38.222-07:00

OK. Resubmitted with a smaller fig 1 and the typos pointed out here fixed (thanks all!).

Argh. First "official" comment back from the jounr...

2009-08-28T12:33:49.743-07:00

Argh. First "official" comment back from the jounral. They won't print a 12 panel figure like Figure 1. Guess I won't show the one low-res one.

Very good article. Everything is remarkably well e...

2009-08-28T10:53:43.607-07:00

Very good article. Everything is remarkably well explained. Thanks :D

About the paper, I'm afraid I can only detect typos, like Alcareru did. Here's a list:

Several "Titans" instead of "Titan's": near the end of the Introduction, 4th and 6th line of Observations, 2nd line of Analysis and 3rd line of Discussion.
Last paragraph on Observations: "ofpotential" and "-surface".
Analysis: "calcuations" (3rd line).
Discussion: "earth" instead of "Earth" (1st line).

Also, I see a lot of JPEG compression on figures 1 and 2, and it seemed to be there before the addition of arrows and circles. This makes features in the images difficult to see…

But that's it. Good and interesting work!

Hi, Mike :) I had to sleep on this for a while. ...

2009-08-28T10:42:56.439-07:00

Hi, Mike :)

I had to sleep on this for a while.

On page two, it says, "...methane should be seasonally transported from summer
pole to summer pole (Mitchell 2008)". OK, that would mean that the methane doesn't go anywhere. Didn't you mean, "...from summer pole to winter pole..."?

The chart on page 5 is pretty interesting, especially the region between 2.5 and three microns. I guess analyzing detailed differences would be beyond the scope of the paper. You guys think you could model up a graph of what pure methane ought to look like? Maybe that's beyond the scope of this paper, grist for some future paper.

I need to get busy with differential equations homework, so this is really a quick read through rather than a review.

I'd like to comment on the low depth of Titan's mountains. I'm wondering: how deep does the aquifer go on Titan? That's obviously beyond the scope of the paper but it seems both Titan and Earth have "the right" amount of liquid.

Thanks, Chuck! :D

-Michael C. Emmert

Chuck -- I didn't know about the EGU journals. Ver...

2009-08-28T10:15:34.577-07:00

Chuck --
I didn't know about the EGU journals. Very cool sounding. Taking a quick look at the actual journals, though, it doesn't look like weather on other planets would fit anywhere, would it?

I understand your comment about self-referencing. It's an interesting balance. In general many of the things one does are related to things in the past, so you build this common body of work that you then often cite. But it can also be a sign of laziness: you know your own work best and it comes to mind instantly when you're looking to throw a reference in. I will go make sure I didn't do that!

Mike

Second to last word in the abstract needs an -ly o...

2009-08-28T04:15:11.028-07:00

Second to last word in the abstract needs an -ly on the end.

“The best examples are shown in Figure 1.” God bless you for not calling your best example ‘typical’.

Your argument would be stronger if you could show that your fog appeared in areas where rain had previously occurred. Otherwise, any source of cold methane could give you fog (e.g. an endothermic methane-producing chemical (or photochemical) reaction). Will 2NH3 (s) + 3C2H6 (l) -> 6CH4 (g) + N2 (g) proceed to the right under Titanian surface conditions, assuming an ammonia component in the surface ice?

Your references are very self-referential. Is no-one else in the world studying methane weather on Titan?

If ethane is a stable dead-end liquid, then why is there so little of it on the surface?

If you want online reviewing, why didn't you submi...

2009-08-28T03:38:20.751-07:00

If you want online reviewing, why didn't you submit to an EGU climate journal, where open reviewing comes standard?

Fascinating paper. While I'm not able to contribut...

2009-08-28T02:01:29.612-07:00

Fascinating paper. While I'm not able to contribute anything from a scientific standpoint, there's a possible typo in section 2 Observations, Paragraph 1, Line 8,:
"We also added an addition synthetic filter......." Should read " an additional" ?

Otherwise, a good experience for a layperson to get a look at an academic paper, and a great idea to try out this kind of mass participation.

Not sure I can contribute anything useful with res...

2009-08-27T15:30:15.558-07:00

Not sure I can contribute anything useful with respect to your paper. However, a comment on this blog article:

...make the air colder so it can hold less water and all of that excess needs to condense.

and

...the air gets too cold to hold the water that is in it...

Though they are, in a way, literally correct phrases like this make me cringe as they reinforce the myth that the air is somehow like a sponge which can hold so much water vapour at a given temperature.

This gives people badly misleading ideas in two areas related condensation that I'm peripherally interested in: building science and meteorology related to gliding and aviation in general. I've also heard some confusion expressed about this with respect to dew on amateur telescopes, though in those cases it didn't make any difference to the substance of the discussion.

Fantastic news! Congratulations on this discovery....

2009-08-27T15:29:55.477-07:00

Fantastic news! Congratulations on this discovery.