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Lakes in the limelight, the 2013 image bonanza continues
titanicrivers
post Mar 16 2017, 02:24 AM
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Juramike (Mike Malaska) has a new article in Icarus on the possibility of Nitrogen bubbles affecting large patches of the N polar seas as seasonal changes occur. A great image of the N polar region and a summary of the article are found on the Cassini website https://saturn.jpl.nasa.gov/news/3008/exper...-with-nitrogen/

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Ian R
post Mar 25 2017, 02:02 PM
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2017-03-20 Titan A Double Take


2017-03-21 Cassini Snaps Zero-Phase Titan


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TheAnt
post Apr 21 2017, 04:24 PM
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The features that appeared then to disappeared in liquid on Titan have indeed turned out to be foamy bubbles.
This finding is described in a paper in Nature and a popularized treat on the subject is found in Universe today.
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nprev
post Apr 21 2017, 08:52 PM
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Much of this work was done by UMSF moderator Juramike, who is quoted extensively in the Universe Today article. wink.gif


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JRehling
post Yesterday, 03:45 AM
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This fizzy seas result is one of the most science-fiction-like things I've read in planetary science. It's like something out of a comic book. Congratulations, Mike.
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rlorenz
post Yesterday, 03:40 PM
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QUOTE (TheAnt @ Apr 21 2017, 11:24 AM) *
The features that appeared then to disappeared in liquid on Titan have indeed turned out to be foamy bubbles.


No they have not. The study (to which I also contributed) showed that nitrogen bubbles could be formed in certain circumstances. Such bubbles
could account for some transient phenomena observed on Titan's seas (aka 'the magic island' observed in radar) but they
cannot account for all the transient features observed (notably by VIMS, which only sees the top fraction of a millimeter of
material).

A more parsimonious theory is that surface roughness (either locally wind-driven, i.e. 'catspaw', or nonlocally - i.e. wind-driven
currents) explains all the observed transients.

Bubbles are still fun to think about, though.
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Juramike
post Yesterday, 11:45 PM
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Yeah. A funny thing happened on the way to the Universe Today article....

About a month ago we had a press release that presented our Icarus paper on experiments to figure how much nitrogen goes into lake fluids. Lotsa fun implications. Lakes "breathing" in and out, gas release from liquid mixing, cool stuff (!). And we stated pretty much "Oh yeah, and bubbles might possibly could be an explanation for observations of Magic Islands in Titan seas." I mean, sure, it's still on the list of possible suspects.

A month later, another paper comes out in Nature Astronomy that describes model calculations (not using our new lab data, I might add) that had a press release saying that the problem was solved.

And somehow in a funky twist, the Universe Today article combined the Nature Astronomy article's press release first paragraphs with the last paragraphs of our earlier press release.

So basically, we got an extra bonus 15 minutes of fame riding on the back of a later paper that came to some of the same conclusions that we'd already published earlier.

I'm really not quite too sure what to make of all this....

But as for the observed Magic Islands in the lakes, I agree with Ralph that wind is a good (and leading) suspect for Magic Islands. But the properties of Titan lakes definitely causes some funkiness. (As in, no freezing of methane on Titan - but that's not a new discovery, our lab experiments just help with the "why".)


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ngunn
post Today, 07:23 AM
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I have a question about the way patches of bubbles might produce RADAR reflections. Please excuse me if the answer is already in one of the papers: I don't have access. Are we talking about bubbles distributed through the body of the liquid or a raft of some sort of scum accumulating on the surface?
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Webscientist
post Today, 12:28 PM
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Thanks Ralph and Mike for your courageous experimental study about the bubble phenomenon. Risky I guess with all these volatile hydrocarbons... unsure.gif
In Ligeia Mare, I note that the coastline near the "Magic Island" is particularly irregular with numerous peninsulas or bays.
I can imagine strong erosional processes in that area as well as potential disturbances in streams.
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rlorenz
post Today, 07:52 PM
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QUOTE (ngunn @ Apr 23 2017, 02:23 AM) *
I have a question about the way patches of bubbles might produce RADAR reflections. Please excuse me if the answer is already in one of the papers: I don't have access. Are we talking about bubbles distributed through the body of the liquid or a raft of some sort of scum accumulating on the surface?


These are quite distinct hypotheses. Floating material (e.g. pumice rafts, or some sort of bubble foam) could explain both radar and near-IR brightness, as could surface roughness from wind or currents.

A bubble plume, with voids in the methane column, could give radar backscatter, but not near-IR.

A bubble plume would be expected to be anchored to the seafloor somehow ; floating material would be pushed around a lot by wind, so the magic island's recurrence at one spot might argue somewhat against it, although some sort of pumice analog continuously/episodically released from a seafloor volcano would have some preference for location, I guess.
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