Titan Review article |
Titan Review article |
Dec 14 2007, 05:02 PM
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#1
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Member Group: Members Posts: 611 Joined: 23-February 07 From: Occasionally in Columbia, MD Member No.: 1764 |
This just out. Not earth-shattering, but colorful - maybe handy as an up-to-date
Titan intro http://www.jhuapl.edu/techdigest/td2702/lorenz.pdf |
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Dec 16 2007, 08:12 PM
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#2
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Junior Member Group: Members Posts: 98 Joined: 30-November 05 From: Antibes, France Member No.: 594 |
I bought in 2004 "Lifting Titan's Veil".It's of course the reference for Titan and I will reread it very soon to compare with what we know now ( presented in Titan revealed).
I'm fascinated by the radar images of the lakes in your Titan review.Unfortunately, the radar images don't give any indication on the appearance of the liquid.Does it appear dark, orange, blue... from a human eye? Some dark and uniform patches located on the "white snow" of Iapetus made me think they were pools of hydrocarbons, similar to what we might find on Titan. Do you think that the idea is relevant? |
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Dec 17 2007, 01:37 PM
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#3
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Member Group: Members Posts: 611 Joined: 23-February 07 From: Occasionally in Columbia, MD Member No.: 1764 |
I'm fascinated by the radar images of the lakes in your Titan review.Unfortunately, the radar images don't give any indication on the appearance of the liquid.Does it appear dark, orange, blue... from a human eye? Some dark and uniform patches located on the "white snow" of Iapetus made me think they were pools of hydrocarbons, similar to what we might find on Titan. Do you think that the idea is relevant? Lakes - get asked this a lot. Dunno. Probably like one of those 'Random_City at night' postcards - black. Since the lakes are at the poles, its often nighttime. Sun and saturnshine is always low on the horizon, never high in the sky, and only red light filters down to the ground. If you brought your own white light with you, depends. Pure methane would look blueish - like Neptune - because of the methane absorptions in red. But if there is a lot of reddish tholin suspended in it, maybe brownish (wine-dark sea?). So mostly black White snow - even stuff like benzene (for example) at liquid nitrogen temperatures is white. I think maybe anthracene is yellow (maybe Juramike can explain how things get dark/colored?). Soot of course is black. I don't think we can rule out any of these of Titan (or Iapetus, for that matter..) |
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Dec 17 2007, 04:53 PM
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#4
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Member Group: Members Posts: 706 Joined: 22-April 05 Member No.: 351 |
Pure methane would look blueish - like Neptune - because of the methane absorptions in red. But if there is a lot of reddish tholin suspended in it, maybe brownish (wine-dark sea?). Ralph - In all the discussions of Titan missions, has anyone discussed putting a "lander" in the one of the lakes to study their composition? All - At the AGU conference, there was a poster proposing that the "land" area around the lakes might be a lot like the karst regions of Earth where the liquid has eroded the surface into dramatic shapes. It would be beautiful to see, but I can't imagine an engineering team ever agreeing that such an area would be safe to land in. ("What part of cliffs and unsafe don't you understand?...) -------------------- |
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Dec 18 2007, 12:33 AM
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#5
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Member Group: Members Posts: 611 Joined: 23-February 07 From: Occasionally in Columbia, MD Member No.: 1764 |
In all the discussions of Titan missions, has anyone discussed putting a "lander" in the one of the lakes to study their composition? Yes. Indeed, my 'class' in the short course preceeding the International Planetary Probe Workshop in Bordeaux in June considered just such a concept Things to consider, though 1. it's been hard enough to argue that the lakes are indeed lakes (and it would be even harder to argue that they will still be lakes when the follow-on mission gets there : if methane, they might evaporate seasonally) so optimizing the payload for lakes specifically is a bold choice. 2. I'd argue that while the lake chemistry may be exceedingly interesting in perhaps not-understood ways (e.g. see the NRC Limits to Organic Life report many threads ago) the known path to pyrimidines, amino acids etc is via hydrolysis of tholins in impact melt sheets and cryolava flows. If you had the capability you might land at and sample the edge of such a flow. A lower-tech alternative is to argue the dune sands are likely to contain some component of such material, since the sand has been transported over some distance anyway (and the non-hydrolysis part of such sands is unknown and interesting anyway) |
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