[X] My Assistant

[Guest_BruceMoomaw_*]

It is indeed scheduled to be broadcast on NASA TV tonight, at 2 AM to 3:30 AM Pacific time. (Please, God, let them not cut into it prematurely this time to rerun more stock Shuttle footage.)

[chris]

Its being broadcast as a Real player stream by the BBC at 10:00 GMT. Follow the link from here: http://news.bbc.co.uk/1/hi/sci/tech/4193043.stm

[djellison]

Well Bruce wasnt too far from the mark - they overran some repeats of the next shuttle crew slapping each others back - and BANG straight into the end of Southwoods introduction

Doug

[chris]

Notes from the conference:

Coldest place ever visited - 94K
Ride was a bit bumpier than expected. A lot of swinging under chutes. Below tropopause got a lot gentler.
Rock solid on the surface

Used VLBI + v sensitive receivers on earth. Got a Huge amount of data. They are now calling this "Channel C". Fully recovered doppler wind experiment data. Months of work to analyse all the data collected this way.

Probe landeed at approx 5m/s

Cassini received data for more than 3.5 hrs, and got real data from surface for 72 mins.

Got data for longer from channel C. More analysis required.

Marty Tomasko
==========

Came down on a bright/dark boundary

Rugged terrain - got a stereo view.
They see a ridge system with a peak. Ridge is 100m tall.
Dark channels are evidence of rain. Dark material is likely photochemical smog washed off ridges.
Ridges are in reality quite dark - look bright in comparison to channels.
Ridges are made of ice

They see a river system flows to delta.

New features (the "Airstrip picture).
White streaky pattern is *extruded* ice cut through with channels.
Short stubby channels are different from the dendritic channels, and may indicate *springs or outflows*.

See evidence for fluid flow in dark regions
Stream lines in low lying regions

Elliptical feature next to landing site - pool where liquid has drained away. No liquid now.

Picture from surface. Rounded stones - erosion. Flatter region between may be a stream.

Liquid methane. Lots of evidence of rainfall. Dry pools.

Familiar processes, but with very exotic materials.

Gas spectrometer. Toby Owen
===================

Sets scene with pre-huygens data

No primordial argon krypton, only argon from decay. Strange - perhaps gives interesting clue as to formation of titan.

Photochemsitry high up makes smog particles, which precipitate down.

Puzzle as to how methane is replenished.

Gas abundance vs time graph (descent)

plots N2, ch4, ch3+ (I think it was)

Upper atmos - N2 dominates

CH4 profile descending - similar to water profile on earth

On surface, n2 is stable.
ch4 suddenly jumps by 30% in 3 mins, out of the ground. There must be liquid methane on the surface. It might have rained yesterday.

What have we learned?

Our speculation is pretty good. New thing is that we can detect liquid CH4, not ethane.

"We have a flammable world"

John Zarnecki
=========

SSP data.

Penetrometer - clean measurement of surface characteristics.

First - a high force, then drops, then a lower, more constant force.

done some tests in last 2 days.

Used 'sand' of fine glass particles. produces correct flat profile, not sharp peak. Added a thin glassy, crust. reproduces data from titan.

Motion of whole probe - probably nestled about 10-15 cms into the top soil.

Probe is generating heat, and passing it into soil. this is evaporating the methane out of the soil. SSP instruments show turbulence in material coming up from surface.

Conclusion
=======

liquid methane plays same role as water on earth.

Now have ground truth - will help cassini a lot

Q/A
===

Q: Why no liquid areas?
A: Region seems like arid regions on earth. More like arizona. Rain/ rivers are seasonal, perhaps?

They have more than one stereo pair of the landscape.

Dark materiel in river beds relects 10%, bright is 12%

Might there be less arid places? Entirely possible. Can't say - only seen one place.

Next capability to send Titan is mobility - fly or float

MER team have called, and want to send rovers to titan.

Cut off, switched to European parliament, I think.

[Guest_BruceMoomaw_*]

Those of you who watched that rather intimate little Huygens press conference (virtually all the talking was done by Tomasko, Zarnecki and Tobias Owen, in a rather small room) already know all this. But for those of you who didn't: the first big discovery of Hugyens seems to be that methane rain, contrary to what a lot of theorists thought, DOES hit the surface of Titan directly -- and pretty frequently. The landing site is (as I suspected) rather like a terrestrial desert with arroyos and a big playa, which seem to be currently dry -- but they were rained on quite a short time ago (the general impression was left that it was less than a year), and the playa is still muddy. And that smooth, pebble-free region running through the middle of the post-landing photo is indeed thought to be a small, recently wet steream channel (although it's not wet now; they haven't seen any signs yet of liquid pools or puddles actually on the playa's surface at the moment). I imagine the rain comes from those small wandering clumps of methane clouds seen by Cassini; they may be small, but they seem to be very moist, and they may be lower-altitude than previously thought. They may, in fact, be pretty damn dramatic thunderstorms.

Some of the arroyos were definitely carved by surface rainfall; others, with stubbier branches, seem to be sapping channels coming from springs. Also, John Rehling was right in noting that some runoff channels run across the "peninsulas" of stone-studded terrain sticking into the playa. The suggestion was made that these are places where the liquid poured from one part of the playa into a somewhat lower part -- but I'd like to know whether the possibility can be completely ruled out that both they and the springs might be tidally driven phenomena instead, if the tides on Titan are as powerful as has been suggested. Anyway, the rain washes the dark smog off higher terrain on Titan and it accumulates as a dry crust in the arroyos and playas after the liquid evaporates, as we thought. I imagine that -- given the very slow rate at which the smog is produced -- virtually all of it actually gets caught up in the raindrops and carried down onto the surface by them. I suspect that those light-colored streaks seen by Cassini to the leeward side of high features on Titan are not, as I thought, wakes where dry smog dust has not been blown by winds -- but rain shadows instead.

The second big revelation, although less was made of this, is that cryovolcanism is definitely occurring on Titan, and pretty vigorously. One photo taken from serveral km up showed, plain as day, a very light-colored narrow "tongue" of very clean water ice stretching across the landscape, with arroyos starting immediately at its edges and flowing away from them -- as though it was a fairly high, smooth dome of water ice extruded from underground, with the surface so smooth and hard that the rain falling on it doesn't erode it, but instead runs off its slopes onto the older ground-up water ice regolith immediately to each side of it and starts carving gullies only then. But that means that the icy surface of this ridge must be relatively recent, and hasn't been ground up yet into loose ice regolith by meteoroid impacts and whatever other processes slowly grind up the surface ice of Titan. Also, they got some good stereo pairs from the photos -- and the ridge running close to and parallel to the shore in that famous photo of the runoff channels near the shoreline, with rainfall channels running off it on both sides, must be about 100 meters high but only several hundred meters wide. In short, Titan is NOT the flat world I had suspected it was -- except in the basins where the liquid runoff and muddy sediment have accumulated. (No speculation from them as to what's driving the cryovolcanism. Tidal heating?)

Zarnecki confirmed that lab tests do indeed show that the penetrometer profile can be simulated by the instrument's staff ramming through a thin dry surface crust and into softer muddy material below, and that the whole probe seems to have sunk 10-15 cm into the mud. And the heated GCMS inlet, starting 3 minutes after landing, evaporated enough liquid methane out of the mud to raise the gaseous CH4 level going to the GCMS by 30%. (The only other mention made at this point of any other substances detected by the GCMS is that some heavier organics also seem to have been vaporized out of the mud by the heated inlet.) It starts to look as though the methane clouds build up just below the methane cold trap that separates Titan's troposphere and stratosphere, and as I say may grow into pretty dramatic thunderstorms -- although Fulchignoni, who was at the press conference but did very little talking, didn't say anything about any possible detection of radio bursts from distant lightning bolts.

Other things I would have liked to hear more about but which weren't mentioned, besides tides and lightning: the argon level; the altitude (once again) of the lowest pre-landing photos (although the photos they did get, having been greatly improved by further processing, seem more than adequate to give us a good idea of what's going on on Titan); those possible clear liquid droplets on the DISR's windows; and the significance, if any of that double spike in the echo sounder's data (a dried surface crust with a moderately deep mud layer below it, as hinted by the penetrometer?) But Titan has turned out to be a nice dramatic place after all, and much wetter than I really expected it to be -- now unquestionably the first world besides Earth to have a good deal of liquid on its surface (and not just ethane, but liquid methane) -- as well as being a lot more internally active than anyone seems to have suspected. In short, Huygens -- even with only one communications channel working -- has delivered the goods, in no uncertain terms

[Guest_BruceMoomaw_*]

A follow-up on the press conference: The ESA's official article on it is now at http://www.esa.int/SPECIALS/Cassini-Huygen...HB881Y3E_0.html . Two notes: (1) The third photo in the article shows that rather sinuous ridge of clean cryovolcanically extruded water ice. (2) The following passage: "New, stunning evidence based on finding atmospheric argon 40 indicates that Titan has experienced volcanic activity generating not lava, as on Earth, but water ice and ammonia." Somehow I missed this while listening to Tobias Owen's report -- I'll listen to my tape recording of it again.

[djellison]

Bruce- there's a chap over at the HZ suggesting that they can recover data from the VLBI measurements on channel A.

Now - I'm adament that the only data they can construct is doppler data - and they've not actually mentioned extracting telemetric data from channel a recordings on the ground from greenbank/parkes - and that whilst possibly feasable, they've not actually mentioned it as yet.

The confusion being that they say 'recovering data' for the Dopler experiement, where as it's actually generating new data to do the same thing.

Is that how you read the situation - and perhaps you could put this one to bed w.r..t getting anything out of the signal recieved on earth if you know the right person to ask?

Cheers

Doug

[Guest_BruceMoomaw_*]

Yep, Tobias Owen DID discuss Titan's argon -- somehow I missed that whole section on my first listen. And what he said was yet another weird twist to Titan's story. It does have Ar-40 in its atmosphere -- presumably produced by the decay of potassium-40 in its rocky core and then gradually transported up through the ice mantle to the surface -- which was detected not only by Huygens, but by Cassini's INMS during the Titan-A flyby. But they found absolutely no trace of any other noble gases: no Ar-36 or 38, no Kr or Xe -- none of the noble gases which must have been in the icy planetesimals out of which Titan was originally built -- down to Huygens' sensitivity limit (which Owen described as "1/1000 of these gases' level in Earth's atmosphere").

These have been found in the atmosphere of every other world whose air has been analyzed by a mass spectrometer. Something must have completely driven them out of Titan's ices during its history, and surely that something can only be the same tidal heating that drives its cryovolcanism. Just as Titan, on its surface, seems to be an eerie cryogenic analog of Earth's deserts, complete with occasional thunderstorms and flash floods interrupting the usual aridity -- so, internally, it starts to look like a strange icy analog of Io, with tidally generated volcanic and tectonic activity strong enough to totally erase its impact craters, and volcanic vents spewing methane from its interior (probably from CH4 clathrate).

The one thing I can't quite figure out, given my rudimentary scientific knowledge, is why Cassini's INMS showed that Titan's nitrogen IS isotopically fractionated and therefore cannot be replenished from its interior, unlike its unfractionated methane -- despite the fact that its volcanic activity must be frequently oozing liquid water-ammonia "lava" to its surface. Is it just that Titan is cold enough that virtually none of the ammonia to reach its surface ever evaporates into the air? Also, that's one other subject that I would have liked to see mentioned at the press conference: whether those occasional weirdly straight (and parallel) dark arroyos that Huygens photographed -- looking like irrigation ditches rather than rivers, and mixed in with the twisting ones -- run along the valleys between parallel tectonic compression ridges. I imagine they do.

Anyway, Titan and Iapetus have now both fully lived up to the hopes people had in advance of how strange and individual they might possibly be. And -- judging from Cassini's new long-range shots of Enceladus, revealing that previously unseen side which turns out to have virtually no craters, large and parallel curving ridges, and a clear and sharp edge separating it from the rest of the moon's surface -- it too will not disappoint us when we get our first close look at it next month. What could have created that? Internal tidally driven activity, or is it the palimpsest from a giant impact?

[Guest_BruceMoomaw_*]

Regarding Doug's Channel A question: the clear impression I got is that Lebreton was simply referring to their ability to recover all of the Doppler wind data from the radiotelescopes' probe signal reception. He didn't say anything specifically about recovering telemetry that I heard -- although I'll take another listen to that section, too, to see if I overlooked anything.

[Guest_Sunspot_*]

....but there must be places on Titan right now where large amounts of liquid have pooled on the surface....If the dark areas are where liquids have remained on the surface at some point... what might we find in the dark areas seen in the images below ?

[volcanopele]

okay, we are having a very hard time with a lot of their annoucements. Me thinks there will be a lot of arguing at LPSC From what I hear, and I still need to listen to the press conference, that many of the complaints here are with the lack of definitive numbers (i.e. no figure for the relative humidity near the surface) and the fact that they presented their information as fact not as current working theories has disturbed many of us here, not to mention our disagreement with their landing site determination (not just me, for the sake of the landing site lottery).

1. If it rained yesterday, where are the clouds??? VIMS, ISS ,and Keck have NEVER seen clouds in that region and we have only seen one cloud streak at that latitude in all of our observations. It may have rained last rainy season, but certainly not yesterday.
2. why no discussion of tectonics? The "airstrip" and other linear channels are clearly tectonic in origin.
3. The argon, phew, I thought I went crazy for a second. I thought I heard that the INMS detection of material at mass=40 was argon but then I was told it couldn't be because primordial argon would have a lower mass.
4. Sunspot: That's a good question. I don't agree with others on some forums that they are due to large scale tides moving fluids around. The associated features are WAY to large and are due to prevailing winds. The dark material is obviously an area where liquids have flowed based on the Huygens images, though I still like my volcanic plains idea.

[alan]

When would the rainy season be? As it gets closer to the Equinox (~August 2009 I believe) will we see thunderstorms?

[volcanopele]

When would the rainy season be? As it gets closer to the Equinox (~August 2009 I believe) will we see thunderstorms?

rain showers. There would be no thunderstorms (methane isn't polar). Based on our view of the clouds, my guess would be late winter/early spring and late summer/early fall. So for the huygens landing site, this would be ~2009-2011

[lukemeister]

Hi - Did anyone record the streaming video of today's press conference? I set up WM Recorder to grab it while I slept, but unfortunately it conked out just as Toby Owen was getting started.

Unfortunately I don't get NASA TV on my actual television.

Thanks,
Luke

[volcanopele]

there's an MP3 recording here: http://tinyurl.com/729gn