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Posted by: Stu Jan 12 2009, 06:01 PM

Interesting...

http://www.spaceref.com/news/viewpr.html?pid=27336

Posted by: djellison Jan 12 2009, 06:02 PM

Methane?

Posted by: Stu Jan 12 2009, 06:06 PM

I reckon so... after all, all those plesiosaurs, scorpion-people and "blue suited humanoids" must break wind sometimes...

Posted by: elakdawalla Jan 12 2009, 06:16 PM

Mike Mumma's name is synonymous with methane.

--Emily

Posted by: Tesheiner Jan 12 2009, 07:09 PM

I'm just trying to remember... wasn't something "methane related" already reported few months ago, ESA perhaps?

Posted by: remcook Jan 12 2009, 07:09 PM

For more detail you could probably look at Mumma's DPS talk, though that talk may not be online anymore.

Posted by: lyford Jan 12 2009, 07:16 PM

Awkward silence

Posted by: helvick Jan 12 2009, 09:03 PM

Yep Methane and with the others on this Press Conference it seems to me that the emphasis will be on the implications for biological origins. Now before anyone goes postal those implications could, of course, be negative.
Checking out the other names home pages shows that they all have notable experience researching Methane in Mars Atmosphere:
Sunil Atreya (Mars Express PFS, Sources and sinks of methane on Mars .. )
Geronimo Villanueva (Search for Biomarker Gases on Mars, Identification of a New Band System of Isotopic CO2 near 3.3 µm: Implications for Remote Sensing of Biomarker Gases on Mars .. )
Lisa M. Pratt (Director NASA Astrobiology Team, Life in the Deep Subsurface of Earth and Mars, Long-Term Sustainability of a High-Energy, Low-Diversity Crustal Biome .. )

Posted by: Juramike Jan 12 2009, 10:04 PM

Here's some handy numbers (source: http://en.wikipedia.org/wiki/Mud_volcano)

On Earth, mud volcanoes are estimated to belch out about 2E11 - 1E14 m3 methane per year (at STP).
= 8.79E12 - 5.49E15 mol CH4
= 141E12 - 88E15 g CH4.

(The estimated amounts vary wildly, the numbers above are at the high end of the range. It's about 5-10% of the total methane output, most being biogenic).

What I didn't realize is that the main route for destruction of methane in Earth's atmosphere is reaction with hydroxyl radical in the upper atmosphere. Would this be a similar process for removal of methane from the Martian atmosphere, or would direct photolysis (CH4-->CH3. + H.) be operative? Or would dust grains be a catalytic surface?

Here's a handy link on tropospheric oxidizing processes on Earth: http://www.atmosp.physics.utoronto.ca/people/loic/chemistry.html#2.3%20Oxidation%20of

-Mike

Posted by: stevesliva Jan 12 2009, 10:43 PM

Isn't the methane emitted from mud volcanoes originally biological in origin, even if it's geological now?

Posted by: Juramike Jan 12 2009, 11:45 PM

Dunno. I always assumed it was from oxidation of iron minerals with H2 reduction of carbonate rocks. (http://en.wikipedia.org/wiki/Serpentinite)

[olivine + wa-wa + carbon dioxide --> serpentine + magnetite + methane]

(Fe,Mg)2SiO4 + nH2O + CO2 --> Mg3SiO5(OH4) + Fe3O4 + CH4

-Mike

Posted by: Tom Tamlyn Jan 13 2009, 12:52 AM

There's some interesting http://mainlymartian.blogs.com/semijournal/methane_on_mars/index.html on Oliver Morton's wonderful blog, Mainly Martian.

The blog is now, alas, largely inactive, but for a year and a half it was a leading source for news of the rovers and unequaled for thoughtful and extremely well informed commentary on the rovers and planetary exploration generally. (Another starting point for the methane discussion is the http://mainlymartian.blogs.com/semijournal/2004/03/two_thousand_co.html post.)

Mainly Martian is worth reading in chronological order, starting http://mainlymartian.blogs.com/semijournal/2003/12/new_writer_star.html, and it's a shame that the site doesn't make it easier to do so.
It's practically a sequel to Morton's book on Mars, http://www.amazon.com/Mapping-Mars-Science-Imagination-Birth/dp/0312245513 itself an outstanding discussion of the state of Mars exploration on the eve of the Rover landings. The book is also a meditation on the experience of visualizing a distant planet, and provides a kind of historical and philosophical background to the activity of umsf.com.

TTT

Posted by: tdemko Jan 13 2009, 02:43 AM

The methane from most large mud volcanoes (e.g. Caspian Sea region and Indonesia) is most likely biogenic gas from the degradation of near-surface hydrocarbon accumulations.

For newbie mud volcanologists, http://bulletin.gia.az/ is a great place start.

Posted by: HughFromAlice Jan 14 2009, 10:07 AM

Methane!! Yes, this could be a v interesting update/briefing.



I posted this in topic Local Methane Plumes On Mars a few months ago. In particular, check the interesting replies........ The problems on interpreting gases in the Martian atmosphere at parts per billion using ground based spectroscopy, alternative explanations for methane production such as via a Sabatier type process (good basic reference in Wikipedia) and Mars Express results.

For a start, I wonder if the update will be based on data derived from ground based spectroscopy???!!!

Posted by: Enceladus75 Jan 14 2009, 11:15 PM

I hope that it has to do with a detection of methane by an orbiter spacecraft, to verify/back up the Earth based spectroscopy claims. This would be a really exciting finding either way.

Or it might be do do with the erosion/stripping away of Mars's atmosphere and the implications of this for its geological and hydrologic history and lilkihood of standing water bodies on the surface in the past.

Posted by: ilbasso Jan 15 2009, 02:48 AM

http://www.thesun.co.uk/sol/homepage/news/article2133475.ece is claiming that NASA will announce that the methane is from microbial life.

Posted by: Stu Jan 15 2009, 06:19 AM

It MUST be true then. I have every faith in a paper that claims a low-flying UFO recently snapped a blade off a wind turbine, and that the lovely "Debbie, from Hull" is still 20 after having been on page 3 for at least 5 years...

Posted by: Sunspot Jan 15 2009, 11:42 AM

The story is starting to appear on quite a few news sources now.

Posted by: djellison Jan 15 2009, 11:48 AM

Of course, until the news conference, there isn't actually a story.

Posted by: Pertinax Jan 15 2009, 01:03 PM

But, but... what about the story about the story that might me? That's a story too isn't it?


-- Pertinax

Posted by: Oersted Jan 15 2009, 01:11 PM

WE'RE ALL GONNA DIE, RUN, RUN!!!!

Eh, ok, I'll wait for the press conference...

I believe methane was also discovered by Mars Express back in 2004.

Posted by: OWW Jan 15 2009, 01:54 PM

Forgive me, but I don't understand why methane = life.
Titan and the gas-giants' atmospheres also contain methane and nobody claims that there are little green bugs on those planets.

Posted by: ugordan Jan 15 2009, 02:00 PM

Clinging for straws, IMHO.

Posted by: djellison Jan 15 2009, 02:25 PM

It was. There have also been hints of it from ground based obs, and orbit obs. What I'm expecting ( although this is a guess ) is a map of its distribution across Mars- all be it at very very very low res. It should give us a hint of where it might be coming from.

Doug

Posted by: Juramike Jan 15 2009, 03:32 PM

Or at least about the dynamics of the upper atmosphere and where it concentrates for detection.
[I'm guessing this has less public appeal.]

Posted by: SirBruce Jan 15 2009, 04:34 PM

According to news reports, the latest science have correlated the methane detections with water vapor clouds, strongly suggesting a biological linkage instead of, say, a volcanic origin.

I understand this, but I do have a question for you scientists out there. Wouldn't any volcanic subsurface heating that released methane up through the soil also cause melting of any subsurface ice, thus resulting in the release of both methane and water vapor at the surface? While I'm all for believing there is microbial life on Mars, I'm not sure why this isn't a possible explanation, and thus why a correlation doesn't necessarily point to biological over volcanic processes. Perhaps there are other geophysical reasons to exclude this, but I would appreciate any thoughts along those lines. (And if any of you have access to the scientists at or after the press conference, please pass this question along to them!)

Posted by: centsworth_II Jan 15 2009, 04:48 PM

I continue to be disappointed in the failure to include the possibility of photochemical generation of methane in the discussion whenever biological and geological sources are considered.

If methane is found in association with water clouds, is it to be implied that organisms generating the methane are present in the clouds? Is it not even more likely that the water in the clouds is used in a photochemical reaction creating the methane? I'd like to see the possibility at least addressed.

Posted by: Juramike Jan 15 2009, 05:05 PM

That makes sense to me.

Posted by: Juramike Jan 15 2009, 05:12 PM

As written on Fox News:

"(American media outlets are not yet reporting the story because they're honoring an "embargo," a promise to not run a story until a designated time, in this case 2 p.m. EST, when NASA is expected to hold a press conference. The Sun "broke" the embargo, prompting other British papers to follow suit.)"

So that's the story behind some of the story...

Posted by: djellison Jan 15 2009, 05:26 PM

The story here, is that Astrobiology is off topic for UMSF. Rule 1.2. This is the first, last and only warning. In the post press-conf rush, I will not hesitate in hitting the delete button or issue suspensions.

Posted by: SirBruce Jan 15 2009, 06:05 PM

Wow, guess things have changed since I stopped reading UMSF months ago. I recall all sorts of discussion in the past. I guess there must have been some thread that got out of hand and you laid down some new rules. Too bad; I'm not much interested in a place that's going to completely ban astrobiology discussions just to keep a lid on UFOlogists and the like. Good luck to you, Doug.

Posted by: Sunspot Jan 15 2009, 06:24 PM

That's a bit heavy handed...care to elaborate on the reasoning behind that?

Posted by: djellison Jan 15 2009, 06:29 PM

So be it. I am sure you, and anyone else who wants to discuss it can do so elsewhere. I will almost certainly join in the debate over at www.bautforum.com , for example.

I am not completely banning astrobiological discussions. I'm not saying that no one can discuss it. But the rules of UMSF dictate that you can't discuss it here. It's not what UMSF is for. Everyone is totally free to talk about them elsewhere - and I'll probably join you! Yes - this is a baby out with bathwater issue. Rather that, than descend into a bickering fringe-theory conspiracy infested argument about astrobiology and methane. The price to pay for keeping UMSF to the standards we do, is the exclusion of things that may risk damaging it.

Posted by: Sunspot Jan 15 2009, 06:35 PM

That's a somewhat contradictory statement.

Posted by: Hungry4info Jan 15 2009, 06:55 PM

If you want, you can discuss it on the Extrasolar Visions' website.
http://solar-flux.forumandco.com/news-and-discoveries-f6/update-on-martian-atmosphere-t237.htm#1388

Posted by: imipak Jan 15 2009, 06:59 PM

Edit - remove silly question. Apologies for the noise.


Seasonal variation is interesting, surely if the methane is being generated relatively far from the surface seasonal temperature and/or atmospheric pressure variations shouldn't affect the local conditions; unless the processes that are destroying it vary, instead (dust devils, as suggested by one slide?)

Posted by: Juramike Jan 15 2009, 07:17 PM

And the evidence is not clear either way....space.com article http://www.space.com/scienceastronomy/090115-mars-methane-news.html.

The part I found even more fascinating that methane being created, is that methane is being destroyed faster than expected.

The soil chemistry of Mars seems to extend into the atmosphere....
(peroxide laden dust grains possibly doing the oxidizing)

-Mike

[EDIT: The article did state that volcanism as the source is not likely, since other gases associated with such event were not observed. But down-deep serpentization is still a possible source.]

Posted by: Stu Jan 15 2009, 07:21 PM

Anyone know of an "audio only" link for this? My ******* broadband connection is ******* useless tonight and the NASA TV is re-buffering every twenty ******** seconds!!!! Any minute now... ANY minute now.... I'm putting my fist thru the screen...

Posted by: Paolo Jan 15 2009, 07:32 PM

On NASA's portal http://www.nasa.gov/mission_pages/mars/news/marsmethane.html

Posted by: imipak Jan 15 2009, 07:37 PM

http://news.bbc.co.uk/go/rss/-/1/hi/sci/tech/7829315.stm piece.

Posted by: tty Jan 15 2009, 07:41 PM

The only way to pin the origin of the methane down would seem to be the carbon isotope ratio. Anybody know if the MSL laser spectrometer is sensitive enough?

Posted by: PDP8E Jan 15 2009, 07:41 PM

mars atmosphere is active
Methane plumes are seen in certain regions (Nills Fossea, Syrtis)
Methane then breaks down over months
It appears to be seasonal (lowest levels at equinoxes)
It could be geologic (simplest)
It could be biologic (ties into seasons?)
Nobody knows yet.

More study required

Posted by: Juramike Jan 15 2009, 07:44 PM

Probably not even then. As just mentioned in the broadcast, other biomarker gases could be used to support a biogenic origin. But do really pin down the origin and the process you'd need to get to right to the source.

Drill, baby, drill!

Posted by: djellison Jan 15 2009, 07:46 PM

It was written in a hurry. The point I'm making is that people can talk about anything they want. But they can't talk about biology, here. People object as if I'm banning them from discussing the subject. I'm not. I'm saying you can't talk about it HERE, in this forum, with these rules. It's not as if people can't go and talk about it somewhere else. Sorry if that was not clear.

There are things I want to talk about that, if I posted them here, I, in my admin role, would delete them, and then ban myself resulting in a catastrophic rip in the forum-time continuum. I know the rules for UMSF, so I stick firmly within them. If I want to discuss things that are outside the scope of UMSF (and regularly, I do) I visit BAUT usually.

Posted by: Juramike Jan 15 2009, 07:52 PM

The source could be clathrated methane (see avatar for structure) emplaced long ago, only now being liberated through seasonal vents.

So the carbon isotope ratio could have been locked in at the time of clathration long ago.

Posted by: imipak Jan 15 2009, 07:52 PM

Active hotspots identified are Terra Sabae, Nili Fossae and Syrtis Major. From my visual memory of the slide, the first source was extended north-south, with the other two being "point sources" (at the resolution of the data, anyway) roughly level with the top and bottom of the Terra Sabae source - very very roughly:

Edit: NASA TV's now showing a pre-recorded interview with Mike Mumma.

Posted by: ngunn Jan 15 2009, 08:03 PM

Exactly my thought. I don't understand why this wasn't mentioned. Are we missing something?

Posted by: SirBruce Jan 15 2009, 08:04 PM

I wasn't going to post again -- I've found most admins don't care to discuss their policies in-depth -- but given that this has dragged out a little bit, what the hell, I feel the need to add my two cents.

I think this is either a very weak defense, or simply muddying the waters, or is missing the point. Of course you mean you are banning them from discussing the subject HERE and not elsewhere. What, do some people think you're god? Do you have control over the entire Internet? Maybe you're getting at that you're an admin elsewhere. But in any case, people who are objecting are objecting because you're choosing to ban it HERE, and the fact that it's a valid topic elsewhere is more or less irrelevant to their (or at least, my) feelings and objections.



I can respect the desire of admins to create such rules in order to keep conversations from getting out of control, but in this case I think it's a misguided rule going way too far. A huge part of unmanned spaceflight science is astrobiological in nature. It seems bizarre to ban such discussion of that. I can't imagine trying to discuss measruements from Mars landers and rovers, or extrasolar planet observatories, all the while cautiously avoiding any mention of biological implications of those results. A whole chunk of the discussion of the nature of organics on Titan was related to their value in analyzing pre-biotic, if not ultimately biotic, chemistry. In this very thread, even after your previous warning, other people have already discussed biology. How can people even discuss the NASA press conference, without discussing the very questions and answers which were focused on biology at least 80% of the time? I presume if NASA someday *did* announce an unmanned probe discovered life on an extrasolar body, it would become a valid topic to discuss here? Seems kind-of silly that it can't be discussed until then.

But, as I said before, it was not my intention to come in here and cause a big ruckus about the rules. You can run your site as you want; I'm simply disappointed and my subsequent interest in posting here after years of lurking is substantially reduced.

Posted by: elakdawalla Jan 15 2009, 08:10 PM

Let me try to explain in a different way. This site is moderated and administered by humans who have interest in space exploration, in all sorts of different topics, and we spend the time it takes to moderate this site because we generally enjoy the discussions. However, some discussion topics -- for example, astrobiology and human spaceflight -- have, in the past, generated more than their share of administrative headaches, to the point that the ratio of our administrative headache to our enjoyment of the discussion has just gotten too high for us to want to continue to deal with it, even if we may be interested in the topic. Therefore, we push discussion of such topics to other forums -- astrobiology to BAUT, human spaceflight to nasaspaceflight.com -- where those site administrators have proven more willing and interested in moderating the discussions than the particular group of administrators is here.

--Emily

Posted by: Juramike Jan 15 2009, 08:10 PM

Gas hydrate release was mentioned several times during the convened panel discussion.

The tricky part will be trying to differentiate all the possibilities: current geological release, release of trapped stuff directly from clathrate, clathrate release to an underground storage cap with an even later release, or biological (or even past biological gases being trapped). Isotope ratios will help, but I think it'll be a lot of challenging (and rewarding) work to try to get to the bottom (pun on multiple layers there) of the methane release.

Posted by: stevesliva Jan 15 2009, 08:17 PM

Speaking of-- and feel free to delete or move this comment-- but Craig Covault was let go by Aviation Week and is now working for spaceflightnow.

Posted by: djellison Jan 15 2009, 08:20 PM

As I've said elsewhere in similar discussions - accusations of baby out with bathwater are expected, and at least partially justified. But that's the price that I consider worth paying. Emilys posts explains it very very well.

No - I don't think I'm some internet god. But I fail to see why people go 'Wahahh - I want to talk about X'. What is stopping them doing that? Nothing. Find a place where it's allowed, and do it. I don't complain that I can't talk about manned spaceflight, or religion, or biology, or politics, or other off topic stuff. I stick to the rules and find somewhere else to talk about the issues I want to talk about that are not within the remit of UMSF.

UMSF is, intentionally, about a very very small subject area. S/N ratio is the currency of forums, and this one is, fortunately, quite high. I don't intend to risk it on subject matter that is, at its core, off topic. What is and isn't acceptable in a forum is more than just reading it's URL and assuming that's it.

Doug

Posted by: Julius Jan 15 2009, 08:20 PM

Any ideas as to whether current Mars orbiters with radar have studied the undersurface of such regions on the planet releasing Methane gas?

Posted by: ollopa Jan 15 2009, 08:22 PM

I couldn't help noticing that two of the panelists have a close association with the MEX-PFS instrument. Sushil Atreya (a thorough gentlemen) is on the PFS team and Geronimo Villanueva is Official Reviewer of the MEX-PFS Archive. I'd have liked to hear MUCH more about how Mumma's work might help sort out the genuine problems with PFS calibration. Can Vittorio Formisano go back and recalibrate?

Posted by: silylene Jan 15 2009, 09:06 PM

i do wish that the researchers did not seriously consider photochemical generation of methane as a significant source of abiogenic methane.

Please refer to this thread, or even older threads in SDC (with many references) : http://www.unmannedspaceflight.com/index.php?showtopic=1671&hl=methane

From the synopsis of the press conference I read on SDC by MW (sorry, I missed the press conference): I would like to see chemcial kinetic rate data that photolysis takes 'centuries', or was this a conjecture? It would need to be a steady state effect: methane is both being produced and being lost. The concentration observed reflects the chemical kinetics of these two processes.

The map of methane production shown (I recall we went over this before, in the pre-Pluck and also pre-crash SDC forums), and indeed in the pre-crash SDC also!) gives the highest methane production in the Martian equitorial band. This is exactly what would be expected if it were a photochemical process, since this would occure in the areas of highest irradiance.

The photochemical process I proposed (see the link above, or for more information, the older links in SDC) was a photoreduction of CO2 catalyzed on metal oxide dust surfaces with hydrogen (which comes from water). The dusts (TiO2, for example, this works with several types of oxides) serve as catalysts for this effect. in fact, I would expect areas in which the dust is uplifted due to winds or dust devils to expose more dust catalyst for methane photoproduction. So you may see the highest rates where there is both high irradiance, and higher concentrations of exposed metal oxide dusts. I also recall about 2 yrs ago that, I came across a paper which found some atmospheric photoreduction chemistry occuring on the dusts from the soil surfaces in Chile'se Atacambra desert, which is a rather good stand-in for the Martian conditions.

Also, one would need to correlate the seasonal variation lifting or exposure of exposure of dusts which may serve as catalysts. And/or correlate the seasonal variation in the concentration of H2O in the atmosphere may be inportant too, as this is the source of H2 for the photreduction of CO2 to methane.

Until I see more, I am very unconvinced of the need for a biogenic methane source. I am looking forward to reading their journal paper to see how they treated the photochcemical generation.

Posted by: gpurcell Jan 15 2009, 09:19 PM

FWIW, looks like the observations were purely Earth-based, from the Mauna Kea observatories.

http://www.spaceref.com/news/viewpr.html?pid=27373

Posted by: marsbug Jan 15 2009, 10:03 PM

If that is correct it does go against a biological source, you'd expect microbes to be concentrated in areas where water ice was more common and there was some chance of liquid water.

Posted by: ilbasso Jan 15 2009, 10:24 PM

I just hope we NEVER get back a picture from Spirit or Oppy with a critter perched on one of their solar panels! We wouldn't be able to talk about it! We could, however, play with various projections of it.

Posted by: Sunspot Jan 15 2009, 10:34 PM

This is the last i'm going to say on this issue, but I felt I had to respond.

More and more of NASA's research and discovery aims are becoming astrobiology related as a result of the unmanned spacecraft visiting more and more destinations. Possibile subsurface oceans on Europa and Ganymede... and the latest discoveries at Enceladus by Cassini. I remember the tremendous excitement and anticipation surrounding Opportunity's first discoveries at Meridiani relating to water and possible past habitability. Phoenix and the polar Ice too. The future MSL will have a substantial astrobiology element to the mission.

These latest results will surely have an impact on future design and instruments to be sent to Mars which is why I found the suggestion that people could be banned or suspended for discussing them truly astonishing.

Posted by: djellison Jan 16 2009, 12:32 AM

Then talk about them in a different forum - what's stopping you? People get banned or suspended for breaking the rules. The rules are there for everyone to see. People get warnings and a heads up when they're running the risk of breaking those rules. We even gave a specific warning in this very thread.

If someone gets banned - it's because they refuse to respect the rules.

UMSF was started, as you will remember, as a place for people to share their mosaics, and talk about what the MER's were up to. Its scope has grown and grown and grown for 5 years. Lines have to be drawn to dictate what is an isn't allowed to maintain the S/N ratio for those topics for which the board was started. Biology, like Politics, or Manned Spaceflight - has baggage. It has too much scope for arguments, bickering, personal ranting campaigns - and in the specific case of biology, fringe theory nut jobs.

Now, we can try and accommodate that subject and spend, literally, hours trying to keep things at a reasonable level, get accused of bias or inconsistent treatment - and the end result is the very occasional interesting topic and an enormous quantity of unseen administrative workload, annoyance, hassle, insults, accusations and entirely unjustified stress.

OR - we can simply say no to that subject entirely, giving admins and mods little bits of their lives back, keeping the ammount of administrative workload to a minimum - and above all, maintain the S/N ratio of the subjects for which this forum was started and is maintained.

If you want to talk about Biology, try the www.bautforum.com - it's brilliantly maintained, conducive to interesting discourse, and a perfect home for that sort of discussion. It's what I do - and I can see no reason why anyone else would object to doing the same.

Posted by: Fran Ontanaya Jan 16 2009, 12:41 AM

Oi, if there's snow, snow will be studied, not polar bears.

The detection of plumes sounds interesting. I hope the sources can be pinpointed with HiRISE imagery.

Posted by: vjkane Jan 16 2009, 01:15 AM

I just posted a summary of a proposed mission to follow up on the methane discovery at http://futureplanets.blogspot.com/2009/01/following-up-on-mars-methane.html

Posted by: Oersted Jan 16 2009, 01:36 AM

Ok, we´re all getting serious and discussing signal to noise ratio et al, but just remember one thing: this is a discussion of whether something has been farting or not. How serious is THAT?

Posted by: nprev Jan 16 2009, 01:39 AM

Thanks for the interesting summary on your blog, VJ!

Question for the chemists out there: Are CO2/CH4 clathrates possible? Reason I ask is that IIRC the frosts at the V2 site were thought to be 6:1 CO2/H2O clathrates. Wondering if the seasonality might reflect sublimation of a CO2/methane mix, which presumably would have different physical properties.

Of course, that would not explain the origin of the methane unless it's truly primordial & the clathrates are ancient.

Posted by: Juramike Jan 16 2009, 02:00 AM

Are CO2:CH4 clathrates possible?

If you mean CO2 trapped in a methane cage structure....No I don't think so.

The cage structure relies on intermolecular hydrogen bonds to set up a cage structure. So the "cage former" requires some sort of polar atom to hook up to other buddies with a healthy strong hydrogen bond interaction.

CH4 is pretty much a boring little tetrahedral greaseball: Not good for making cages. So the strongest bond you could get would be a non-polar dispersion ("VanderWalls" is a passe term these days) interaction of a hydrogen atom dispersing into the orbital cloud of another methane molecule. Very, very low lattice energy. Theoretically, it *might could* form a cage, but I would think it would need to be at temperatures approaching absolute zero to make any type of cage structure.


-Mike

Posted by: nprev Jan 16 2009, 03:43 AM

Sounds less stable than me after an hour without a beer. Thanks Mike, as always, for the lucid and readable explanation!

Posted by: eoincampbell Jan 16 2009, 04:00 AM

The rules page is quite a read itself...
Simple, yet undeniable...
All Hail UMSF...

Posted by: dvandorn Jan 16 2009, 05:36 AM

While there will be an awful lot of study and theorizing about the source(s) of the observed methane, and an awful lot of modeling of said sources, I think perhaps one of the things that needs to be really pinned down hard before those models gain any credibility is the volume of methane being released over time. I know they have some figures right now, but they're only showing plumes in three small-ish areas of Mars. Are those the *only* sources? Or have we not looked closely enough at the rest of the planet to find others?

Once you know how much you're releasing, you can project total release levels over much longer periods, like millions and billions of years. If it turns out, for example, that the current release rate (which is really very low on a planetary scale, I believe) would over a billion years require that a methane ocean has to have been sealed up and slowly leaked out over that period, that makes the ancient origin theory unlikely. If it would only require a few thousand tons of clathrated methane, spread out over only perhaps several thousand total cubic kilometers (a very small percentage of Mars' upper crust), then the ancient origin theory looks a lot better.

If the release volume, as projected against a variety of assumption sets, seems to require constant (if very low-level) production of methane over time, then the various other theories gain more ground.

(And yes, I know that release rates have probably changed over time. You can plug such changes into the release-over-time models, if you wish, as long as your changes are in some way supported by actual data.)

One thing that was just mentioned at the press conference (I recorded it on my DVR and am watching it now) is the possibility that there might be a layer of permafrost under the entire Martian crust, even the equatorial plains. Do we have any real evidence of this from either of the radar experiments? Or is this simply another model they're tossing around?

More and more, I want to get heat flow data from Mars. An awful lot of what's actually happening under the first few km of Mars' crust depends on the temperature regimes of its crust, mantle and core. We have very little idea of how much remanent heat may yet be contained within the planet, how heterogenous (or not) its distribution might be, and very specifically at what locations and depths water (and other things, like methane) might exist as solids, liquids and even gasses.

-the other Doug

Posted by: HughFromAlice Jan 16 2009, 11:44 AM

"Other" Doug - I think you have raised interesting points.

My interest is in what the next generation of Mars orbiters and ground based craft should be looking at. Mumma noted that our past focus on following geology/minerals lead to the choice of Meridiani as the landing site for Opportunity and to the subsequent 'cornucopia of information' culminating with evidence of standing water on Mars. Now we need to target missions to investigate active areas.

He was also at pains to point out that his data analysis and control of instrumental artifacts was 'unassailable for any point of view"!! Is there anyone in UMSF really up in spectroscopy that has read Mumma's recent Science paper and would like to comment on the algorithms/techniques he used? Would be interesting to hear from an expert.

I thought a lot of really key things in this press briefing came out towards the end as the panel loosened up after a few questions from the audience.

Villanueva noted that a lot more can be learned from going back to their (massive) data sets (and CRISM data sets for gen mineralogy) in the light of these results. Particularly checking how old the water is that has been detected along with CH4. Old production - new release or new production - new release? He then commented that they are doing this and will submit a paper for publication soon. Also Mumma made allusions to more papers to come soon - such as looking at seasonal repeatability.

Mumma pointed out that if 'bio' is near the surface then it should be using water that is in contact with the atmospheric escape and so will have a high D content. But water below permafrost is ancient and likely to be much lower in D. Then to throw the cat among the pigeons, Pratt pointed out that we know very little about D/H ratios due to radiolytic splitting of water. (So we need to do more research here on earth before anything else!!).

She continued that CH4 and D/H ratios would not be enough for absolute proof anyway - we would need to positively identify a suite of biomarker gases like turpines etc. etc. If we can't do this, we will need to drill down and pump water out! She pointed out that to verify life that exists in thin films deep underground on Earth it is necessary to filter 100,000s of litres of water and then either visually identify the life forms or grow them! We'll need a mighty spacecraft to drill and pump!!! Mars Science Laboratory might get very very lucky and sample concentrated gases at a release point which would - at least - give us strong indicators.

Sushil Atreya also commented that we need to look on the ground for heavy hydrocarbons. If ethane and propane were found then geo source would be more likely. Mumma said that they have began to look at this in 2006 and that there will be a publication later in the year. Another one?

For me the most interesting comments of all came from Lisa Pratt. She pointed out that it is much easier to make a living consuming methane than excreting it. There is an enormous amount of sulphate on the surface of Mars. Sulphate reduction coupled to methane oxidation starts to look like a very attractive proposition. On Earth, this metabolism in one of the most ancient ones. So if methane is coming out in focused areas then it gives us a bull's eye to go in and search.

Now that's what I call a really exciting hook to get priority funding for new missions to Mars ---- despite my fascination with Titan (especially) and Europa!!! After all, if that wonderful memorandum of mammary masterpieces - the UK paper 'The Sun' - found it worthwhile to go to the trouble of making a major scoop on a Mars story for its readers, then the pollies might actually see a few votes in it!!!

Posted by: silylene Jan 16 2009, 02:36 PM

I'll read it hopefully today and report back my thoughts. (I am a PhD polymer photochemist).

Posted by: marswalker Jan 16 2009, 06:44 PM

Well researched. A theory is that water, iron oxide, C02 from the atmosphere, and volcanic heat could cause reactions resulting in methane production. However... we have yet to see evidence of ongoing volcanism (not that it's conclusive, we just don't have the evidence there).

Given results from various orbiters and Mars Phoenix Lander, there is plenty of evidence to support the possibility of bacterial life on Mars.

We've found plenty of water-ice, the other chemicals (perchlorates, etc) we've found do not eliminate life (as we know it) as a possibility.

Everywhere we find water on the Earth, we find something living in it.

In any case... it's pretty neat!

[the other] -Mike

---

Posted by: marswalker Jan 16 2009, 06:49 PM

Not to mention the levels of UV - once at the surface, any sort of "cage" or structure in the methane would probably be "blown-apart" by UV.
Methane "wants" to come-apart.

Posted by: marsophile Jan 16 2009, 10:59 PM

There is one ingredient for habitability that, as far as I know, we have not yet found on Mars: nitrogen (except for small amounts in the atmosphere). Please correct me if I am missing something.

Posted by: nprev Jan 17 2009, 01:51 AM

I thought that there was in fact a small fraction of nitrogen (3%?) detected in the atmosphere by the Vikings.

BTW, the lead story on spaceflightnow.com now (sic!) implies that MSL retargeting might be under consideration as a result of this discovery. The story seems a bit overblown to me. IIRC, it was written by the same journalist that experienced some controversy regarding perchlorates in the Phoenix samples...please correct me if I'm wrong, anybody.

Posted by: mchan Jan 17 2009, 03:33 AM

Craig Covault. Considered by many folks as one of the top aviation and space journalists. Accolades when he was recently let go by Aviation Week:

http://www.nasawatch.com/archives/2008/11/sad_day_for_avi.html

I enjoyed reading his AvWeek articles years ago when I had time to go to the library and read AvWeek. He gets leads that very few other writers get. E.g., his recent article in Spaceflightnow:

http://www.spaceflightnow.com/news/n0901/14dsp23/

Bottom line, there is very probably some substance to the MSL targeting story. Giving more consideration to one of the landing sites in light of recent discoveries is not exactly earth (or Mars) shaking. How much more consideration, we will have to wait and see.

Posted by: nprev Jan 17 2009, 03:45 AM

Thank you, MC. My suspicious-sounding words undoubtedly did the man an injustice; he appears to be an exemplary journalist in many ways.

Perhaps the proper way to put my impressions is that there does not seem to be (as yet) enough specific information available concerning the methane discovery to modify MSL landing site decisions, and perhaps Mr. Covault's article reflected an ebullent optimism he detected from some of his sources which will undoubtedly subside somewhat after further consideration of the findings to date.

Don't get me wrong; if there's anything close to a localized CH4 emission site within MSL's capabilities to explore, that should be THE target, game, set, and match, siddown & shut up! I just think that it's a bit premature to discuss retargeting MSL based on this information at this time.

Posted by: mcaplinger Jan 17 2009, 05:35 AM

Covault's article says "The MSL rover's launch was recently delayed... but the slip could enable a new landing site selection related to the methane findings, says Michael Meyer, the lead Mars program scientist at NASA headquarters in Washington." I think we can safely assume that Covault didn't fabricate what Mayer said, but as you say, it's not much of a revelation. Given that the putative methane concentrations cover areas hundreds or thousands of km across, I'm not sure how anyone thinks MSL could land "near a vent" or what it could do if it did, but clearly there's lots of time to consider this.

FWIW, Covault has a slight taste for sensationalism; I think Mike Dornheim, who was killed in a car crash in 2006, did a better job of covering JPL for AW&ST.

Posted by: elakdawalla Jan 17 2009, 06:08 AM

One of the press at the briefing (I didn't write down who) pointed out that Nili Fossae -- recently eliminated as a landing site option for MSL -- was one of the places that appeared to be belching methane, and asked if NASA would reconsider. Meyer replied that Nili was the most borderline of the landing sites from an engineering constraint standpoint, implying that its odds haven't really improved after this discovery. But then he went on to say that there were now two more years available for MSL landing site selections, and that things could still change, as the EDL capabilities of MSL will be better understood with time (implying that Nili may become less borderline).

--Emily

Posted by: imipak Jan 17 2009, 10:11 PM

I hadn't heard of the concept of sub-permafrost liquid brines before the presentation, but searches on those terms finds some fascinating work investigating the phenomena on Earth by Dr Lisa Pratt, who was on the panel on Thursday. Much of it gets into non-UMSF topics, but focussing on the engineering requirements for a putative surface campaign to drill into such brines, it's noticeable these boreholes went down to more than 1000m. So, question: how far down would hypothetical Martian sub-permafrost brines be?

Posted by: silylene Jan 18 2009, 02:24 AM

From Science Daily: http://www.sciencedaily.com/releases/2009/01/090115164621.htm

"We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tons of methane," said co-author Geronimo Villanueva of the Catholic University of America in Washington. "The plumes were emitted during the warmer seasons, spring and summer, perhaps because ice blocking cracks and fissures vaporized, allowing methane to seep into the Martian air."

I do wonder if the words ' plumes' and 'were emitted' bias the assumption of origin. I really do hope that the authors do find out in time that their words were chosen wisely!

Of course if all that methane came from one or several vents during the warm season, that would be a HUGE amount !

But let me analyze it another way. From the maps of Mars with methane levels, let's assume that high signals for methane were found conservatively over about 10% of the Martian surface (it actually looks more like about 20+%).

Assuming that methane is formed on about 10% of the Martian surface, and over a 90 day warm period, then the generation level is 13g/km^2/day, or about 0.000013 g / m^2/day. I do think this is not too much for a photochemical generation source. So I do wonder how a photochemical mechanism was dismissed as a source. I am very interested in reading this paper!

Calculation:
Mars surface area = 144 798 500 km²

19,000*2000/2.2 / (144798500*0.10) / 90 * 1000g = 13 g/km^2/day

13 /1000/1000 = 0.000013 g / m^2/day

Posted by: nprev Jan 18 2009, 08:05 AM

Good analysis, Sily; thanks!

The issue at hand is really whether the methane is coming from vents (fractures or fumaroles), or from some sort of widespread low-yield chemical reaction on the surface. Obviously MSL is not presently equipped to detect the latter, nor are any of the operational orbital assets at Mars really capable of detecting transient phenomena like emission plumes unless a real stroke of luck occurs. Therefore, I'd have to call retargeting MSL to look for methane-emitting sites based on current information a highly risky strategy in comparison to, say, examining phyllosilicate beds which have been localized with a high degree of confidence.

Posted by: centsworth_II Jan 18 2009, 09:39 AM

Remember about a year ago, NASA was deciding which of two would be the next scout mission to Mars?
As reported in http://www.planetary.org/blog/article/00000820 the two proposed concepts selected for further study were:

* Mars Atmosphere and Volatile Evolution mission, or MAVEN: The mission would provide first-of-its-kind measurements and address key questions about Mars climate and habitability and improve understanding of dynamic processes in the upper Martian atmosphere and ionosphere....
* The Great Escape mission: The mission would directly determine the basic processes in Martian atmospheric evolution by measuring the structure and dynamics of the upper atmosphere. In addition, potentially biogenic atmospheric constituents such as methane would be measured.... (my emphasis)

NASA chose MAVEN. I wonder how useful the methane measurements made by a Great Escape Mission would have been. I wonder how sensitive such a mission would have been to detection of possible unambiguous bio markers such as turpines. Maybe an upstart space agency, not NASA or ESA, will see this as a chance to get an orbiter to Mars to specifically map the methane and look for other organics. That would certainly be a feather in someone's cap.

Posted by: centsworth_II Jan 18 2009, 09:50 AM

If the methane is coming from a "chemical reaction on the surface", MSL should see some mineralogical characteristics unique to those areas where the reaction occurs. If the reaction is photochemical, the reactive surface would have to be in plain sight.

Posted by: HughFromAlice Jan 18 2009, 10:46 AM

Great that you followed up these ideas. Very interesting and well thought out.



I also agree with nprev's comments.



I was just replying when I noticed that centsworth-II had basically just said most of what I was going to say and had said it better. So I hit the delete button. Anyway go India - China!

CH4 by photolysis - Anyway you stimulated me to check out in more depth info on the formation of CH4 by photolysis in the martian atmosphere. It looks like the topic is still under debate! For instance, "methane observed on Mars can be formed by photolysis of water vapor in the presence of CO, in addition to possible geological sources, rather than biologically" in Bar-Nun and Dimitrov in Icarus Vol181 March 2006 refuted by Krasnopolsky "One of the key reactions is effectively blocked by O2 in the martian atmosphere, and another key reaction does not exist. There are no pathways for effective formation of methane in the martian atmosphere" in Icarus 188 June 2007. Find via http://www.sciencedirect.com/

I'm getting more and more fascinated by all this........to the stage of being tempted to take out a subscription for Icarus!!

Thanks again Silylene!

Posted by: sci44 Jan 18 2009, 12:04 PM

Thats interesting - only 13g CH4/km2/day (1.3g/km2/day globally) - its not much to account for. Another possibility I havent seen mentioned yet is the formation of CH4 by Electrical activity within Dust Storms. There you have the energy input/heat plus the possible presence of catalysts in the dust, acting on atmospheric CO2 and traces of water:

Directly: CO2 + 2H2O + Energy -> (With catalyst/intermediate reaction) CH4 + 2O2

Or acting with any Olivine within the dust (see Juramike's post here too):
Indirectly: (Fe,Mg)2SiO4 + 4H2O + CO2 --> Mg3SiO5(OH4) + Fe3O4 + CH4

My question being: could lightning/electrostatic energy be another source of energy for this reaction - apart from volcanic heat/sunlight?

Again, just a bit of speculation, YMMV. Feel free to laugh me out of court..

Posted by: AndyG Jan 18 2009, 02:36 PM

I'm having a hard time getting my head around the seasonality of a subsurface production. Assuming a regular generation and subsequent build-up of subsurface (abiotic) methane, vented when ice sublimes: how does new ice form to plug any "vents" year-on-year when that liquid is being lost over geological time?

That alone suggests a greater likelihood for photochemical production (or sci44's electrically-aided dust-storms - which could be easily tested by tying in observations to global dust-storm events?)

Andy

Posted by: Fran Ontanaya Jan 18 2009, 02:58 PM

Dr. Peter Smith talked briefly about that possibility during the last Phoenix press briefing.

BTW, Nili Fossae/Syrtis Major seem to have plenty of olivine deposits.

http://hirise.lpl.arizona.edu/PSP_009652_2115
http://hirise.lpl.arizona.edu/PSP_010285_2090
http://hirise.lpl.arizona.edu/PSP_007411_2010

Posted by: centsworth_II Jan 18 2009, 06:24 PM

Good question. Is it that water vapor continually escaping from beneath the permafrost through fissures freezes in winter to form the plugs but in summer it remains a vapor, leaving the surface? This would match the presence of water found along with the escaping methane.

As far as lasting over geologic time, there could simply be that much water down there. It'd be interesting to see a calculation of how much water is lost per year and what volume would be required to sustain the cycle for a given number of years. The vapor could be coming from a regionally fed liquid aquifer below the permafrost.

Posted by: lyford Jan 18 2009, 08:12 PM

From the Dec. 04, 2008 MSLhttp://msl-scicorner.jpl.nasa.gov/news/index.cfm?FuseAction=ShowNews&NewsID=15
(italics mine)

I wonder if this phrasing was deliberate?

Posted by: nprev Jan 18 2009, 09:17 PM

Oh, definitely it was deliberate; my only question is on what basis they would decide to make a retargeting decision. Publically released information to date is inadequate for that.

Posted by: djellison Jan 19 2009, 03:45 PM

For information - we have discussed the biology issue in the Admin section. The discussion came to a very near unanimous decision that the outright ban on Biology is the right step for UMSF at the moment. Reasons cited include those I've mentioned before, as well as others. In no particular order

- Biology (like Politics or Manned v Unmanned) takes on a religious like status in peoples minds with no grounds for actual debate
- There are no biological instruments flying, or planned for flight.
- Setting a limit for what would or would not be acceptable would be near impossible. There is no fair or valid means to half-open the door on this.
- The administrative workload would increase significantly (high admin workload being the sign of a badly administered forum)
- There are alternate venues that are better suited to these sorts of discussions.

It is by taking difficult decisions like this one, that UMSF has become and continues to be what people admire it for. Such decisions are, to some extent, a judgement call. But the admin team has agreed, that this is the right judgement at this time.

Posted by: ngunn Jan 19 2009, 04:19 PM

I'd been chewing this over and come to the same conclusion - there was nothing else you could do, for now, to avoid having to stay up every night containing wildfires. Let's just hope that no banned items are unequivocally discovered in the near future. Fingers crossed, eh?

Once again, Doug, thanks for everything - awkward decisions and all. We don't say it often enough.

Posted by: Juramike Jan 19 2009, 04:26 PM

Mars methane map made APOD.

Global map of methane release during martian summer available here: http://apod.nasa.gov/apod/image/0901/marsmethane_nasa_big.jpg

Posted by: MarsIsImportant Jan 19 2009, 05:37 PM

Much of the known plumes seem to originate from the Arabia Terra region. Some of the areas with the least amount of methane include Hellas Planitia and Elysium Mons.

Hellas Planitia is a known area where most dust storms originate on Mars. So if dust storms have anything to do with production of methane, then you would have to explain the huge discrepancy in the amount of methane build up there.

Elysium Mons is a known volcanic region. So if volcanic activity has anything to do with the production, then likely that region is truly dead volcanically speaking. I would like to a map that includes Olympus Mons before forming an opinion on that.

Why over Arabia Terra? I think NASA has this correct. This tends to indicate subsurface sources for the methane that maybe unique to that area. What that is, we cannot be sure of yet.

If the source were photochemical, explain the distribution. I would think there would be a distribution bias horizontally over the equatorial latitudes instead of what we actually see. Perhaps it is because of ice reservoirs or perhaps something else.

The known distribution would be a problem for a lot of possible different explanations for the source. Let's face the fact that we need better methane maps. The need might suggest a dedicated mission of some sort!

Regardless, it is a fascinating mystery. I would think following the methane is now a good strategy; but we need the proper equipment and advanced planning to do the job properly. I would think changing the landing spot for MSL would be risky at this late stage, unless there are instruments that could easily be brought aboard to make it worth it. I have my doubts.

Posted by: nprev Jan 19 2009, 05:46 PM

Doug, I support the decision because the rationale is sound, aside from admin workload. Most UMSFers love it here because above all it's a no-drama place where some extremely smart people freely share their ideas with us laymen, and preserving that feature of the forum is certainly a priority.

As Nigel said, we don't thank you & the admin team enough for this place, nor do we express our appreciation as often as we should for consistently keeping the standards high. If it was easy, anybody could do it; you guys aren't "anybodies". Thanks.

Posted by: SpaceListener Jan 19 2009, 07:36 PM

If you do Mars Google, I found the three regions to be about the same northern latitud. However, Syrtis and Nili Fossae are very close and Arabia Terra is about 3,000 kilometers west of the first ones.

The other thing, I have observed the methane distribution thru the APOD picture and found that the plumes are not uniformily distributed all planet but localized mostly in that zone. Is that methane distribution consistent in spite of the fact its intensity varies with the seasons.

These many questions might be solved with the future orbiters with adequate instruments to detect the methane. MSL will have it but it won't see all Mars. Hence, the Nili Fossae would be considered again as the one of the four potentials landings.

Posted by: ArMaP Jan 19 2009, 10:27 PM

Sorry for this question from someone that does not understand these things very well.

When they say "parts per billion", what billions are they talking about, other atmosphere components?

Considering the thinness of Mars atmosphere, how would that translate to Earth's atmosphere?

Thanks in advance.

Posted by: Juramike Jan 19 2009, 11:26 PM

That is an EXCELLENT question.

It would imply one gram of stuff (methane) in a billion grams of other stuff (air).

Here is a more detailed article: http://en.wikipedia.org/wiki/Parts_per_notation

My favorite quote:
"it is not formally part of the International System of Units (SI).[2] Consequently, according to IUPAP, 'a continued source of annoyance to unit purists has been the continued use of percent, ppm, ppb, and ppt.'"

[I count myself among the 'annoyed': for most drug-like molecules, ppm is directly proportional to units molar (M). But if you are comparing with especially heavy or light molecules in the mix, this can throw off the relationship.]

-Mike

Posted by: aggieastronaut Jan 19 2009, 11:28 PM

it seems someone else answered the question before I posted...

Posted by: Juramike Jan 19 2009, 11:58 PM

And I think I know why in this particular case it's easier to use ppb: volume will fluctuate at different pressures and temperatures.

Trying to sort out the volume at the particular temperature (which will vary widely on Mars) and pressure (big difference from Hellas Basin (1.155 kPa) to the top of Olympus Mons (0.03 kPa)) would make trying to calculate concentration of g (or moles) per volume a pain.

But I think the spectroscopic method gives units molar from Beer's law. A = cl: A is absorbance, c= concentration, l = path length.

-Mike

[Fun random trivia fact: the human nose can detect http://en.wikipedia.org/wiki/Vinylguaiacol at 10 ppb on Earth at standard temperature and pressure (STP)]

Posted by: Juramike Jan 20 2009, 12:28 AM

(I just had to run this death....)

At standard temperature and pressure on Earth (273 K, 101.3 kPa), 1 mol = 22.4 L

Assuming a pure N2 (m.w. = 28) atmosphere for Earth: 1 mol/22.4 L = 28 grams/22.4 L.

So air 1 ppb on Earth in 22.4 L (STP) = 28E-9 grams/28 grams (=1 part per billion)
28E-9 grams in 22.4 L = 28 nanograms/22.4 L (STP)

For methane (CH4; m.w. 16), 1 ppb corresponds to is 28E-9 g * (1 mol methane/16 g) = 1.75E-9 mol methane

1.75 E-9 mol methane/22.4 L = 0.078 nM concentration.

***

On Mars, what is a typical pressure/temperature at the surface?

Wild guesstimate/generalization: use 233 K (=-40 C), and 0.6 kPa

So pV=nRT:
For pressure: 22.4 L mol -1 x (101.3 kPa/0.6 kPa) = 3782 L mol-1 at Mars pressure
For temperature: 3782 L mol-1 x (233 K/273 K) = 3230 L mol-1 at Mars surface pressure temp.

Assuming pure CO2 (m.w. = 44) atmosphere for Mars: 1 mol/3230 L = 44 grams/3230 L

So 1 ppb at Mars surface in 22.4 L (Mars guesstimate) = 44E-9 grams/44 grams (=1 part per billion)
44E-9 grams in 3230 L (Mars guesstimate).

For methane (CH4, m.w. 16) this corresponds to 44E-9 grams * 1 mol methane/16 g = 2.75E-9 mol methane

2.75 E-9 mol methane/3230 L = 0.8 picomolar concentration. (=0.0008 nM concentration)

Put another way, 1 ppb methane on Earth has 100 times more CH4 molecules per unit volume than on Mars at my guesstimated surface temp and pressure.

(Handy data for all of you thinking about growing beans on Mars…..)

[/nerdgasm]

-Mike

Posted by: nprev Jan 20 2009, 03:48 AM

...Mike, thou art an ubersciencegeek amongst geeks...thank you very much!

That truly puts this in perspective; ain't very much methane at all, and that actually makes the whole issue even more puzzling. Are there really only a (literal) handful of vents on the entire planet? I know that the crust is supposed to be very thick, but jeez...

Posted by: rlorenz Jan 20 2009, 04:13 AM

Sloppy, Mike, sloppy ;-)

If one cares enough to worry about ppb or whatever not being kosher units, then one should
really note that the litre is a unit of capacity, rather than volume

1 mole occupies 22.4 dm^3 at STP.

Posted by: CosmicRocker Jan 20 2009, 07:09 AM

As if my opinion might be important, I would have voted for such a ban, too.

When you begin to talk about PPBs, PPMs, or even simple percentages, such ratios need further definition to become useful. I normally prefer to think about mass ratios, but volume and weight ratios remind us that there are other perspectives that are useful to consider. 22.4 liters/mole at STP is one of my favorite numbers.

Posted by: nprev Jan 20 2009, 07:58 AM

http://www.skyandtelescope.com/news/37667714.htmlfrom Kelly Beatty over on Sky & Telescope. Apparently there was water vapor associated with the emissions, and they were definitely transient. The plot thickens considerably.

Now, what's REALLY strange is why two or more locales separated by hundreds if not thousands of km seemed to pop off at nearly the same time. Not even close to enough information to make an intelligent guess as to what's going on geologically, if anything. Boy, do we need some seismometers on Mars.

Posted by: Fran Ontanaya Jan 20 2009, 08:10 AM

Is there any chance that they were several drifting burps of the same plume?

Posted by: nprev Jan 20 2009, 08:16 AM

I suppose so, but there's no way to tell. The data is at planetary-scale resolution, so it's obviously well past the originating event since the byproducts of the emission have diffused throughout most of a hemisphere.

Think I'm gonna start promoting my Mars Transient Event Detector idea again!

Posted by: centsworth_II Jan 20 2009, 08:24 AM

A sub-surface source to me is the most interesting possibility and I am happy to imagine it is the most likely explanation for the current data. But given the poor time and spacial resolution I don't think a surface process (i.e. photochemistry) is out of the question.

Posted by: nprev Jan 20 2009, 08:27 AM

Cents, I was leaning towards a surface process myself, but the addition of water vapor seems to argue for a more dynamic event. Could go either way still, though; hopefully there will be more data soon.

Posted by: centsworth_II Jan 20 2009, 08:37 AM

The dynamic event could involve the water release only. Once released, the water is involved in a surface process that produces the methane. But, as I said, I'll be happy to have surface production proved wrong.

Posted by: nprev Jan 20 2009, 08:42 AM

Oh, certainly; we'd all like to find a fumarole, but all possibilities need to be considered. Probably a good time to remind ourselves that Mars is an alien world, and terrestrial assumptions do not necessarily apply.

I will admit that I am considerably more excited by this discovery now than I was a couple of days ago.

Posted by: Juramike Jan 20 2009, 01:00 PM

I wonder what the best way to localize transient methane releases would be?

An orbital spectrometer? Or a ground network of landers with some type of 'sniffer' (GC-MS)?

Could a network of upward pointing LIDARs be used for detection of methane absorption bands? Then you'd get cloud/precip data while waiting around for the ground to burp.

Posted by: vjkane Jan 20 2009, 03:09 PM

check out these links:

http://futureplanets.blogspot.com/2009/01/following-up-on-mars-methane.html

http://futureplanets.blogspot.com/2009/01/another-way-to-study-mars-methane.html

http://mepag.jpl.nasa.gov/reports/MSO_SAG2_Report_MEPAG_29may1.pdf

Posted by: dvandorn Jan 20 2009, 04:38 PM

Not trying to be a sadonecroequomasochist, here, but one request for clarification, on the "biology question," if I could.

I imagine that any future landers or orbiters which would feature biology-oriented sensors would provide allowable bases upon which discussion of those sensors and the data they collect would in fact be proper. And that, for example, any credible new interpretation of the Viking biology experiments might be allowable, but again within the strict context of the experiments themselves and the specific data returned.

Am I understanding this correctly? It seems inherent in the standing argument for the ban (with which I do agree, I'm happy not to have to see anyone here deal with the whackos).

-the other Doug

Posted by: silylene Jan 20 2009, 06:53 PM

Mike, thanks for your excellent analysis. I am glad you made this point, it is a key one that we chemists should've made earlier.

Just to run another analysis to the death....

The mass of the Martian atmosphere is 2.5E16 kg http://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html

Working from the APOD map http://apod.nasa.gov/apod/image/0901/marsmethane_nasa_big.jpg
and assuming by my swag guestimate from eyeballing this map that about 20% of the martian atmosphere contains 20 ppb of methane (that looks about correct from the map),

Then there is a total of 50,000 metric tons of methane in the Martian atmosphere. So the observed 19,000 metric ton 'plume' was 38% of the total atmospheric methane.

math: = 2.5E16 * 0.2 * 20 / 1e9 /2000 = 50,000 metric tons

Posted by: silylene Jan 20 2009, 07:15 PM

Thank you, and excellent, just as I expected. A photochemical process which produces methane which is catalyzed over a metal oxide dust or clays requires water. Water is the source of the hydrogen during the photoreduction of CO2. {note: Metal sulfide dusts or minerals could work too as photochemical catalysts, there are papers on this too.}

The detection of water vapor in a region of high solar irradiance are exactly the localized conditions which I was hypothesizing would be required for the photochemical mechanism to produce methane, that I proposed several years earlier over at the SDC forums, and reposted some of the arguments into a UMSF thread here: http://www.unmannedspaceflight.com/index.php?showtopic=1671&hl=methane

{p.s. The photochemical mechanism I have proposed on SDC and then on UMSF is quite different from that later published by Bar-Nun (thank you Alex Blackwell for a copy of his paper from Icarus back then) (and whose hypothesis is disputed in a subsequent letter). Bar-Nun's mechanism was direct high energy photolysis without a catalyst. It's problem is that the light at that wavelength may be highly absorbed, and not reach the surface with much intensity.}

If I wasn't so busy with my job, which is in a very different field, I would do some research and publish a paper on this. if anyone here is qualified to pursue this, I would be happy to collaborate.

Below are a few of the score(s?) of photochemistry papers on the photoreduction of CO2 with water with shorter wavelength light (250 nm - 450 nm). Light of these ultraviolet wavelengths should reach the martian surface in significant doses. There are at least 20 journal papers on the subject of photoreduction of CO2 to produce methane, of course none having anything to do with Mars:

+++++++++

Photoreduction of carbon dioxide and water into formaldehyde and methanol on semiconductor materials. Aurian-Blajeni, B.; Halmann, M.; Manassen, J. Weizmann Inst. Sci., Rehovot, Israel. Solar Energy (1980), 25(2), 165-70. CODEN: SRENA4 ISSN: 0038-092X. Journal written in English. CAN 94:124490 AN 1981:124490 CAPLUS

Abstract

Heterogeneous photoassisted redn. of aq. CO2 to produce MeOH [67-56-1], HCHO [50-00-0], and CH4 [74-82-8] was achieved by using semiconductor powders with either high-pressure Hg lamps or sunlight. The reaction was carried out either as a gas-solid process, by passing CO2 and H2O vapor over illuminated semiconductor surfaces or as a liq.-solid reaction, by illuminating aq. suspensions of semiconductor powders through which CO2 was bubbled. Best results, under illumination by Hg lamps, were obtained with aq. suspensions of SrTiO3, WO3, and TiO2, resulting in absorbed energy conversion efficiencies of 6, 5.9, and 1.2%, resp.

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Reaction mechanism in the photoreduction of CO2 with CH4 over ZrO2. Kohno, Yoshiumi; Tanaka, Tsunehiro; Funabiki, Takuzo; Yoshida, Satohiro. Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Kyoto, Japan. Physical Chemistry Chemical Physics (2000), 2(22), 5302-5307. CODEN: PPCPFQ ISSN: 1463-9076. Journal written in English. CAN 134:185804 AN 2000:788525 CAPLUS

Abstract

The surface species produced during photoredn. of carbon dioxide with methane over zirconium oxide were obsd. by IR spectroscopy. One of them was a reaction intermediate and decompd. to CO at .apprx.623 K, and the other did not decompd. even at 673 K was called a carbonaceous residue. IR spectral features allowed to identify the latter as the surface acetate. Several properties of the former species were quite similar to those of the surface formate ion, which was a reaction intermediate in photoredn. of CO2 by H2 over ZrO2. The former species was assigned to the surface formate, which was also supposed to be an intermediate of photoreaction between CO2 and CH4. The existence of another carbonaceous residue different that the surface acetate was suggested. The EPR spectrum indicated the photoexcitation of adsorbed CO2 to the CO2- anion radical, and the interaction of the CO2- radical with CH4 in the dark. On the basis of these results, a possible reaction mechanism in this reaction was proposed.
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Titre du document / Document title
Photocatalytic production of methane and hydrogen through reduction of carbon dioxide with water using titania pellets
Auteur(s) / Author(s)
SENG SING TAN (1) ; ZOU Linda (2) ; HU Eric (1) ;
Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)
(1) School of Engineering and Technology, Deakin University, AUSTRALIE
(2) Institute of Sustainability and Innovation, Victoria University, AUSTRALIE

Résumé / Abstract
This paper presents an experimental study on employing a pellet form of catalyst in photo-reduction of carbon dioxide with water. Water was first absorbed into titania pellets. Highly purified carbon dioxide gas was then discharged into a reactor containing the wet pellets, which were then illuminated continuously for 65 hours using UVC lamps. Analysing the products accumulated in the reactor confirmed that methane and hydrogen were produced through photo-reduction of carbon dioxide with water. No other hydrocarbons were detected. Increasing the temperature in the reactor has showed little change on the amount of methane produced.

Posted by: djellison Jan 20 2009, 07:31 PM

...an opportunity to revisit the issue as and when it happens.

In the mean time, a ban on biology is a ban on biology. Like politics and manned.... NO exceptions. These rules are made as simple as possible - to follow, and to police, so there can be no arguments or cries of foul play.

Posted by: silylene Jan 21 2009, 04:45 AM

Thank you Jon Clarke on SDC forum for finding a copy of the Mumma paper preprint, which can be found here: http://images.spaceref.com/news/2009/Mumma_et_al_Methane_Mars_wSOM_accepted2.pdf

I have read it over a couple of times, but not in deep depth on the spectroscopic data.

It seems that Mumma estimates 42,000 tons total methane in the Martian atmosphere at the height of the big 'plume', which is very close to my guestimate above.

Spatial resolution depending on how Mumma's group binned multiple measurements. Measurements were taken on the IRTF scope (3m) in Hawaii, and Keck-2. Best resolution was about 195 km, but longer time exposures and binning reduced this to about +/- 5 degrees of latitude and longitude according to the error bars on the plots, and in 30 min time up to 16x10 degrees (long/latitude) or 948x546 km. So no, this cannot really resolve a 'vent' or identify exactly a surface feature associated with the methane.

Methane was removed quite quickly from the atmosphere, and Mumma suggests that highly oxidized dust surfaces in the atmosphere are responsible. I agree.

He discusses seeps and crater faces as sources of methane.

He has a rather long speculative discussion of biological sources for methane generation.

Photochemical sources of methane are not really considered or discussed, other than a very brief dismissal.

Tomorrow I will read throught the spectrocsopic part of the paper deeper. My two quick reads saw nothing amiss, and his evidence for methane detection seems compelling.

Posted by: dvandorn Jan 21 2009, 05:39 AM

Mumma also said during the press conference that results from other areas of Mars that are being reduced for future publication were totally verboten for discussion at this time. Quite sharp and no-follow-ups in tone.

Is he really saying that these relatively confined areas are the *only* methane plumes on Mars as a whole? If so, why such a sharp cut-off of any discussion of some other areas that have been analyzed? (Or maybe there are other things being discovered in other areas that they're trying pin down before discussing them?)

I guess I just don't see anything unique about the landforms associated with the plumes that you can't find methane-free elsewhere. Seems odd to find methane over only *some* examples of cratered terra-style surfaces but not a majority; same with areas like Nili Fossae, there are at least a few other areas that resemble it, but seem to lack methane. I think it might be difficult to pin down sources and origins of methane that seem to have little to no relation to the landforms from which the gas is being released...

-the other Doug

Posted by: centsworth_II Jan 21 2009, 04:49 PM

In this http://martianchronicles.wordpress.com/2009/01/20/mars-methane-movie/ Mumma says they have discovered methane being released from "several discrete vents, or sites." The truth is that they have seen methane appearing in several areas on Mars. They have not at all discovered it being released from vents, or even discrete sites. He goes on to list the "two principle" possible origins of this methane as biochemistry or geochemistry. Once again photochemistry does not make the list. I wonder how seriously the scientists are taking photochemistry as a possibility and on what merits they are apparently brushing it aside.

And we wonder why the popular press can't get it right.

Posted by: Juramike Jan 21 2009, 05:23 PM

I'm speculating here, (and I haven't yet read the papers posted above), but to get the photochemical reduction of methane from CO2 would require a wet catalyst. The water acting as the hydrogen source. So you'd need wet (or icy) dust grains, probably airborne condensation nuclei in the clouds.

But dust grains in the atmosphere are highly oxidizing. How easy is it to do a photochemical reduction on (or in the presence of) an oxidizing surface?

At first glance, it seems kinda tough...

Posted by: stevesliva Jan 21 2009, 05:39 PM

http://blogs.discovermagazine.com/badastronomy/2009/01/19/mars-methane-media-mess/
He points out that the press release was titled "Discovery of Methane Reveals Mars is not a Dead Planet"

Just sayin...

Posted by: silylene Jan 21 2009, 06:23 PM

Agreed. I think it would require non-oxidizing metal oxide surfaces, such as the grains in clays, and water vapor (morning frosts?). But as we know, large parts of the Martian surface are coated with highly oxidized dusts (superoxides, peroxides, chlorates). We need to know which parts of the martian surface are not dusted with dusts whose surfaces is highly oxidized.

Posted by: marswalker Jan 22 2009, 04:45 PM

The mechanism for converting iron oxide, C02 and water into methane require heat. A theory was that some sort of leftover volcanic heat is doing the cooking, allowing the chemistry to make methane. The problem with that theory is we've never witnessed any sort of volcanic activity on Mars - only the long-dead results of volcanism remain.

So PCHEM processes are being looked at as a possible source, but there seems to be a very good chance that it's from biological processes.

Posted by: marswalker Jan 22 2009, 04:50 PM

And his reference about "dead planet" includes both geological as well as biological definitions. If it's not biologically "alive", it must be geologically "alive", or there wouldn't be active ongoing processes which end in methane production.

Posted by: centsworth_II Jan 22 2009, 09:02 PM

That's the geochemical method. I was proposing that released water would be available for photochemical production of methane. (The forgotten reaction)


Once again, what about photochemical production? Would that rate calling Mars "alive"?
(Of course, Mars is "alive" to many of us already, no matter what is found in the future.)

Posted by: Vultur Jan 23 2009, 08:11 AM

True. It sounds ambiguous, and I think it's meant to be. I've seen a 'dead' or 'geologically dead planet' (or moon) used to mean one which has no volcanism (like Mercury or our Moon).

Posted by: Juramike Jan 23 2009, 02:10 PM

Poking around, it might be possible to use an orbiting downward LIDAR to get localization of trace gas data.
Found this abstract:

Riris et al. AGU Abstract#P51C-212. "Mars Trace Gas Detection with a Remote-Sensing LIDAR". (Abstract http://adsabs.harvard.edu/abs/2006AGUFM.P51C1212R)

From the abstract:
"The small laser footprint and the resulting high spatial resolution, will also allow the identification biologically and geologically active sites for a future landing missions."

-Mike

Posted by: silylene Jan 23 2009, 03:42 PM

This is an interesting idea. I wonder how much power the laser would require, in order to generate a significant enough scattering signal to be observed from orbit with good S/N? Also, what's the vertical resolution? And would this just work during the martian night, for that wavelength? (I am guessing it might work better then; but if so, it would require on some type of on board energy storage system, such as batteries)

Posted by: tty Jan 24 2009, 12:12 AM

Given the almost complete absence of impact craters on some of the Tharsis volcanoes volcanic activity certainly continued until fairly recently (geologically speaking). Here on Earth some active volcanoes have dormancy periods that run into tens of thousands of years, so the fact that we have seen no activity in a few decades is hardly conclusive.

Posted by: scalbers Dec 22 2013, 05:26 PM

Here is a Mars orbiting LIDAR proposal...

http://www.lpi.usra.edu/meetings/marsconcepts2012/pdf/4202.pdf

Posted by: TheAnt Dec 24 2013, 11:40 AM

Oh yes that's true though there are some craters to be found, IIRC the planetary scientists do think the timespan is quite long like millions of years between each eruption. So we better do not hold our breath in anticipation for the next one.

Then again, if we'd see one in the future, it might be interesting not just for the drama, it might even affect martian climate and perhaps surface missions to some degree (dust) and with such a thin atmosphere to start with perhaps even a slight change in pressure.