Radiocarbon on Titan Options

[ngunn]

http://www.lpl.arizona.edu/~rlorenz/radiocarbon.pdf

This is an interesting speculative article by Lorentz et. al. from 2002 about what might be found. They suggest that radiocarbon on Titan could significantly influence both atmospreric processes and surface contitions in a number of complex ways. Can anyone here tell me if we know anything more definite about this now, from Huygens data or otherwise?

[The Messenger]

Good question. Huygens gcms should be able to give us c14/c12 ratios for the atmospheric methane, but I have not seen any papers on the subject...yet.

[remcook]

Huygens did find a layer of increased conductivity, but that may be completely unrelated.

[Guest_Richard Trigaux_*]

Do you mean the instrument which made the mass spectrum of atmosphere? I remember a spectrum. Unfortunately the methane ray was too large to guess a C14/C12 ratio. Anyway native C14 would appear under the form of larger soot particules, not in methane.

A lander on Titan would have advantage to detect C14 in the ground, it would give a good estimate on soot accumulation, rain frequency over time, etc. If rain is really one time over thousand years in a place, we could for instance easily date the last rain in a place, and perhaps date several alluvion layers, but this may be more difficult.

[Spirit]

Huygens did find a layer of increased conductivity, but that may be completely unrelated.

I think that there was a problem with the instrument that measured the impedance. Some antena bent and the scientists are not sure that the results are correct.

[ngunn]

A lander on Titan would have advantage to detect C14 in the ground, it would give a good estimate on soot accumulation, rain frequency over time, etc. If rain is really one time over thousand years in a place, we could for instance easily date the last rain in a place, and perhaps date several alluvion layers.

Yes indeed. The half-life of C14 is just right for providing a history of recent events over decades, centuries and millennia. These could be vital timescales for gaining a proper insight. A typical space mission as we do them now is just not long enough for all the important phenomena to unfold on Titan. Even a whole human lifespan may not be long enough. I've already urged the need for a very long term monitoring station around Titan for this reason (and I've been wondering about possible non-Plutonium power supplies), but now I see that radiocarbon studies in both atmosphere and near-surface could also be a huge help in adding the necessary time dimension to our understanding.

A footnote for potential Titan colonists: I found a recent discussion on the Advanced Physics forum about using C14 to make batteries that would last for thousands of years ! (will locate and post link if anyone's interested)

[Guest_BruceMoomaw_*]

There has already been some scientific discussion of different kinds of age-dating on Titan (and on other icy worlds, including Europa) -- including C-14 dating on Titan. There's at least one Web document on the subject that I can dig up, given a little time. (Somebody remind me about this if I forget; I'm accumulating a steadily growing backlist of things I've offered to dig up for you guys.)

[ngunn]

Yes please! My rather primitive googling attempts just went round in circles all leading back to Lorenz et al. 2002 - enough to realise the importance of this and whet the appetite for more information . . .

[Guest_Richard Trigaux_*]

On Earth, C14 comes from transmutation of oxygen or nitrogen. On Titan, we have nitrogen. On icy worlds, Mars, Venus, we have plenty of oxygen (into the form of C02). On rocky planets (Moon, Mercury) or non-carbon asteroids, we have plenty of oxygen (under the form of silicates or iron oxyd). So C14 datation can be used nearby everywhere.

The problem on Titan is that a flood rain will drag C14, yes, but very probably it will drag this C14 into ancient layers when infiltrating into the ground. So likely the ages of the different layers will be blurred. This is a common problem on Earth, called contamination, which makes the datation of soil layers or ancient fossils into the soil difficult. But a recent rain on Titan would left a span of C14 (very probably in a patchy pattern in the Tchernobyl style) which could allow to trace more or less recent rains. Provided of course that a ship is able to fly above large ranges of Titan surface, while detecting, not the C14 itself, but somme X rays coming from its desintegration. At a pinch, this would be detectable from orbit (not sure, because of the thick atmosphere) and give a C14 map which, as we can expect, will corellate with the dark material map.

[ngunn]

Fascinating. I didn't realise C14 decay produced remotely detectable X-rays. The situation on the ground might be very complicated in places, but I think we could in principle disentangle the signals from carbon deposition and the various forms of subsequent transportation, at least for some simpler locations, perhaps enough to make rainfall history maps.

Also, if the radiocarbon is trapped in grains that survive transportation largely intact we could learn a lot about the recent history of a particular location by dating a statistically large sample of individual grains within an assemblage.

[Guest_Richard Trigaux_*]

C14 produces an electron. But when this electron interacts with matter, it ejects electrons from lower layers in atoms. When an upper layer electron falls in to fill the empty layer, it emmits X rays, with an energy dependent only on the atomic number considered. This is used on Oppy with the alpha X ray spetrometer. But the later uses alpha particules, and much more energetic than C14, so there may be not many X ray photons emiited per C14 disintegration.

After, the X ray have to go through the air. To orbit? I realise that the Titan atmosphere is much thickier than Earth's, to give 1.5 bars with a lower gravitation. Earth atmosphere is already a very good shield, equivalent to 10m of water, so Titan air won't allow radiations from the ground to raise to orbit. So this can only work with some plane or baloon at low altitude. Even it will have to be very sensitive. Happily C14 is very probably the only source of radiation, even cosmic rays will not pass such an atmospheric shield. And no uranium, no radon are present into the icy ground. So there are few X photons to detect, but with a very low background noise.

By the way, the energy of the X-rays would hint at the composition of the surface, as it is a function of the atomic number of atoms. carbon=soot, oxygen=water, nitrogen=ammonia, others=big surprise.

This is what I know, and not for very sure. Perhaps you should ask to a specialist, before designing an instrument!

[J.J.]

<<The problem on Titan is that a flood rain will drag C14, yes, but very probably it will drag this C14 into ancient layers when infiltrating into the ground. So likely the ages of the different layers will be blurred. This is a common problem on Earth, called contamination, which makes the datation of soil layers or ancient fossils into the soil difficult.>>

My thoughts exactly. Without something like flora or fauna to take up the C-14 and sequester it, I think using for dating would be difficult. If we're lucky though, there may be areas that are particularly suitable for pristine cores, IMO.