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paulanderson
http://www.esa.int/esaCP/SEMA96ULWFE_index_0.html

Relating to Mars Express:

"At the same time, ESAs Mars Express mission is continuing its investigations of Mars, painting a new picture of the 'red planet'. This includes the first ever probing below the surface of Mars, new geological clues with implications for the climate, newly-discovered surface and atmospheric features and, above all, traces of the presence of water on this world."
RNeuhaus
Anyone will assist to the conference in Paris on November 30 (one week from now)?

Any french people might assist to that, Richard, vikingmars, Rakhir or more or not?

Rodolfo
paulanderson
Just a reminder that the press briefing is tomorrow (November 30, 2005) at 10:00 am ET / 7:00 am PT and will be shown live on NASA TV:

http://www.nasa.gov/home/hqnews/2005/nov/H...s_Briefing.html
JonClarke
QUOTE (jamescanvin @ Nov 30 2005, 02:52 AM)
The joke is about ESA's habit of making confirmations of already pretty well established things sound like major discoveries in thier press releases! Not wanting to speak for the jokers, but I'm sure they all agree with your above statement. Mars Express has been a wonderful mission but there PR office is a joke.

Well I thourght it was funny  laugh.gif  laugh.gif

James
*


Really? And how many times does the NASA press office announce they have found evidence of water on Mars? or that a mission will provide a breakthough on our understanding of the solar system or the universe.

The ME press office does an excellent job on a very small budget.

Besides, the tone of the above comments to me appear directed at ME and ESA and not their press office.

Jon
Rakhir
QUOTE (JonClarke @ Nov 30 2005, 11:12 AM)
Really? And how many times does the NASA press office announce they have found evidence of water on Mars? or that a mission will provide a breakthough on our understanding of the solar system or the universe.

The ME press office does an excellent job on a very small budget.

Besides, the tone of the above comments to me appear directed at ME and ESA and not their press office.

Jon
*



I agree with you Jon.
SigurRosFan
http://www.esa.int/SPECIALS/Results_from_M...7ZTULWFE_0.html - Buried craters and underground ice /
Mars Express uncovers depths of Mars


http://www.esa.int/SPECIALS/Results_from_M...A1UULWFE_0.html - Mars Express evidence for large aquifers on early Mars

http://www.esa.int/SPECIALS/Results_from_M...IAUULWFE_0.html - Mars Express discovers new layer in Martian ionosphere

http://www.esa.int/SPECIALS/Results_from_M...B4UULWFE_0.html - Mars Express radar reveals complex structure in ionosphere of Mars

All Huygens Results

http://www.esa.int/SPECIALS/Results_from_M...ULWFE_0_ov.html
Sunspot
PARIS -- The European Space Agency will unveil wide-ranging findings Wednesday from a landing on Titan as well as from the first-ever probing below the surface of Mars, which found traces of the presence of water ice.

http://www.newsday.com/news/science/wire/s...ience-headlines
BruceMoomaw
I think there's a good chance that they're cranking up for some fairly dramatic news at this press conference: I've been told that the initial science results from MARSIS will be released at next week's AGU meeting, and that some of them "will knock your socks off". I also hope we may finally, at long long long last, be on the verge of seeing the issue of "Nature" with the official Huygens results, with this briefing as a prelude to that.
BruceMoomaw
Dammit, I wrote that just before seeing SigurdRosFan's announcement...
Marz
"If we look at today's evidence, the era in which Mars could have been habitable and sustained life would be the early Noachian, traced by the phyllosilicates, rather than the sulphates. The clay minerals we have mapped could still retain traces of a possible biochemical development on Mars,"

Why is the suphate-forming era not suitable for life? Aren't there acidophilic bacteria that like to munch sulfur, like the famous Snottite colonies?
tty
Note that clay minerals also occur in Meridiani, presumably under the sulphatic material.

Wild speculation: could the dark layer under the Burns formation in Mogollon Rim be a clayey deposit? laugh.gif

tty
dvandorn
Doubtful that the underlying deposits at Meridiani are these phyllosilicate clays that the ESA guys were talking about -- they said very specifically that the closest to either of the rovers they detected these clays were more than 1,000 miles away.

-the other Doug
AlexBlackwell
Radar Soundings of the Subsurface of Mars
Picardi, et al.
Published online November 30, 2005; 10.1126/science.1122165 (Science Express Research Articles)
Abstract

Radar Soundings of the Ionosphere of Mars
Gurnett, et al.
Published online November 30, 2005; 10.1126/science.1121868 (Science Express Research Articles)
Abstract
AlexBlackwell
The December 1, 2005, issue of Nature is now online.
deglr6328
I have access to Nature.....Shall I do something naughty? cool.gif or will that merely cause headaches for Doug... in which case I obviously won't do it...
AlexBlackwell
QUOTE (AlexBlackwell @ Nov 30 2005, 06:15 PM)
The December 1, 2005, issue of Nature is now online.
*

Sorry for the bare reference to the entire issue; I didn't take time to type out the two references. For those playing along at home, the Editor's Summary gives the specific references for the Mars Express-related articles (i.e., the Poulet et al. paper and the accompanying News and Views piece by Newsom).
mike
I was going to defend Nature's charging to view exclusive reports and data, but why do they charge, exactly? Is it because they provide a service by filtering out the 'bad' reports and data? Or is it just that magazines like Nature are obsolete in today's widely Internet-enabled world? Why don't these science teams just self-publish the data on some website they control?
elakdawalla
QUOTE (mike @ Nov 30 2005, 12:22 PM)
I was going to defend Nature's charging to view exclusive reports and data, but why do they charge, exactly?  Is it because they provide a service by filtering out the 'bad' reports and data?  Or is it just that magazines like Nature are obsolete in today's widely Internet-enabled world?  Why don't these science teams just self-publish the data on some website they control?
*

Two words: peer review. Anybody can publish anything on the Internet. And they do. smile.gif Publications like Science, Nature, the Journal of Geophysical Research, etc. separate the wheat from the chaff. When a paper is submitted, it is either rejected outright or sent out to other scientists in the same field for review. The reviewers make lots of comments on the paper and advise the publisher whether it should be considered for publication, or should be revised and resubmitted for a second review, or rejected. The original authors revise the paper and at length it may be accepted for publication. This process provides a seal of approval to published papers indicating that their arguments have been read and accepted as valid by a scientist's peers, and prevents a lot of junk from being published. Of course there are drawbacks as well; the process can take a long time (sometimes more than 2 years from initial submission to publication, though Nature and Science are much quicker), and of course it tends to punish radical new ideas. But what that means is that people have to come up with a rock-solid case to prove an extraordinary claim, and that's not necessarily bad. Having a paper published in a top journal is an incredibly important thing for a researcher's status in his or her field. The more refereed publications you have (as opposed to un-reviewed publications like abstracts presented at conferences), the more likely you are to be tenured, to be successful in grant applications, etc.

--Emily
helvick
QUOTE (mike @ Nov 30 2005, 09:22 PM)
Why don't these science teams just self-publish the data on some website they control?
*

The model for web published and properly peer reviewed publication is really only getting on its feet as far as I can see. And to be fair to all concerned it must be accepted that getting a paper published in Nature is worth a lot more to the scientists and institutions than having one published by UMSF (for example) or simply posted on their own website. Efforts like marsjournal.org show that steps are being made in the right direction and hopefully they are pointing the way towards a much better model that publications like Nature can follow.

I would like to see changes that made public, online and searchable archival of such scientific papers mandatory.

I'd be interested in what any of the professional scientists here think.
JonClarke
Publishing in Nature achieves several things. First, it validates your work. Not the data itself, but your interpretation of that data, which is subject to independent peer review. Second, it ensures that your work goes how to a wide audience, hundreds of thosuands of people read Nature, all the science news sites quote Nature. Ditto for Science Third, it is a permanent record, not only is Nature (or any other journal) archived electronically, paper copies exist in thousands of libraries round the world. Even your research group or even the journal were to fold tomorrow, people could still locate your work one hundred years from now.

Publishing on the web does not achieve any of this. Most web published artciles are not peer reviewed, when they are, there is a perception that it is not independent, people will get their mates to do it. There are so many web pages out there that unless people know what to look for the site has a low profile. Lastly web sites are ephemeral, many journals will not accept web links for precisely this reason, in addition to those above.

Impact is critical in science careers. If you publish in, for example Nature, your paper will be regarded as having a high impact. Publish in what is perceived lesser journal and it will have a lower impact. Self publish on the web and it will probably have a negative impact. Positions, scholarships, and grants can all depend on the impact of your work. That is why people publish their studies in recognised refereed journals.

Jon
mcaplinger
QUOTE (JonClarke @ Nov 30 2005, 01:53 PM)
Most web published artciles are not peer reviewed, when they are, there is a perception that it is not independent, people will get their mates to do it.
*


And the paper journals don't have that concern? I'm a bit confused about what web-based peer-reviewed venues you're talking about. I'd say that Dave Paige's new online journal MARS is as well-peer-reviewed as SCIENCE.

That said, you can't beat the prestige of SCIENCE. I guess NATURE is the same way, though I don't like it 'cause they spell all their words funny smile.gif
Phil Stooke
mcaplinger said:

"I don't like it 'cause they spell all their words funny"

They dost nowt!

Phil
paulanderson
Getting back to today's results... smile.gif

As others have noted, the press conference itself left a lot to be desired, I watched it also (I couldn't always hear the speakers or read the slides properly), but the results themselves are wonderful. I've seen various media pieces take different slants on it though, as usual.

Re the ESA press releases today, while larger oceans or seas may now seem less likely in Mars' past (as implied), the new evidence also shows there was still an earlier wet period of non-acidic and "stably present" liquid water (re the phyllosilicates), at least in large aquifers, which pre-dated the acidic and salty sulphates. If life ever did originate in this friendlier period, it could have then survived and perhaps even flourished. Re Marz' comments in post #22, the NASA update from yesterday outlines that kind of scenario:

http://www.nasa.gov/home/hqnews/2005/nov/H...er_secrets.html

"Many types of microbes live in the Rio Tinto environment, one of the reasons for concluding that ancient Meridiani could have been habitable. However, the organisms at Rio Tinto are descended from populations that live in less acidic and stressful habitats. If Meridiani had any life, it might have had to originate in a different habitat. "You need to be very careful when you are talking about the prospect for life on Mars," Knoll said. "We've looked at only a very small parcel of Martian real estate. The geological record Opportunity has examined comes from a relatively short period out of Mars' long history."

Well put, and now we have, it seems, just such an earlier "different habitat."

Also, New Scientist is quoting William Johnson, MARSIS manager at JPL, that the flat subsurface feature in the buried crater could be liquid water, not just ice:

http://www.newscientistspace.com/article/d...an-surface.html

"Intriguingly, the signal reflected from the bottom of the crater is so strong and appears so flat that it may be liquid water. "If you put water there, that's what the signal might look like," Johnson told New Scientist. But he cautions the data is based on only one pass over the region and could be caused by another material."

Just a possibility at this point, but a possibility all the same.
JonClarke
QUOTE (mcaplinger @ Nov 30 2005, 10:45 PM)
And the paper journals don't have that concern?  I'm a bit confused about what web-based peer-reviewed venues you're talking about.  I'd say that Dave Paige's new online journal MARS is as well-peer-reviewed as SCIENCE.
*


They are not perceived to have the same problem. And most of the major journals do have anonymous reviewers selected by independent editors. They also have established reputations, the new web based journals don't. In contrast 90% of what goes on the web is not peer reviewed. Remember the original comment was "Why don't these science teams just self-publish the data on some website they control?" - that is not a recipe for independent review.

Jon
Rakhir
I think nobody can deny that European Public Relations are usually not very elaborated. At least if you take the US PR as a standard.

Japanese PR are similar to European PR.
And I will not detail Russian or Chinese PR.

Therefore, US PR can not be considered as a worldwide norm.

Once you know this, what is the benefit to remind it and whimper every 10 posts ?

Rakhir
RNeuhaus
About the title Radar reveals ice deep below Martian surface

They believe a 250-kilometre-wide circular structure that lies between 1.5 and 2.5 kilometres below the surface of Chryse Planitia is an impact crater that was buried with volcanic ash or soil several billion years ago. The team sees no radar boundaries in material that fills the bowl of the crater and the radar signals lose little strength when passing through it. That suggests the infill must contain a large proportion of ice, which is nearly transparent to radar.

I think it would be probable that there is water at the bottom of impacted crater. Since the crater is 250 km (rather bigger than Gusev's ones with 160 km diameter).

It is located so deep at 1.5-2.5 kilometers under the surface. Then I deducted that the area: Amazonis, in the north plantias has no craters on it must have be resurfaced after the Hesperian ended, since otherwise many craters would have been formed on it.
See the following picture:
The impactors that formed the large basins Isidis, Hellas, and Argyre were so large that there were *never* enough of them to uniformly cover the planet, even in the Noachian. Examine this detailed map of Isidis.

The Isidis crater has 1,125 km diameter
Note that it is very smooth, and is about half surrounded by cratered terrain, and half surrounded by a smooth plain. This suggests that whatever filled in the Amazonian surface flowed into Isidis, but could not cover the southern walls of the basin. Remember from the discussion of the crustal dichotomy that the northern lowlands are lower, and hence easier to cover.

Of course, this discussion is very simplified. There are stratigraphic relationships (like the boundary of Isidis) that are used to determine relative ages, in addition to crater counts. The maps shown here display craters larger than about 100 km, and this can be done more accurately using many thousands of smaller craters (recall from our discussion of crater forms that a 100 km crater is a large crater on Mars.) Also, there are complex curves for the number of impacts of a particular size: the division into three periods is fairly arbitrary.


The major volcanoes can be found on the youngest, Amazonian surfaces. This is to be expected, since the Amazonian surfaces were recently covered by lava and are thus volcanically active. However, it is a misconception to believe that the lava that covered these surfaces came from the visible volcanoes. Instead, these areas are volcanic plains, usually formed from fissures which are then subsequently covered by the same lava that flooded the surrounding areas.

Finally, the found hidden craters in Amazonis Plantias might be true but according to the radar reflection and the shape of the bottom surface (smooth curvature), might lead as an old water deposit.

Rodolfo
Marz
QUOTE (Rakhir @ Dec 1 2005, 09:20 AM)
I think nobody can deny that European Public Relations are usually not very elaborated. At least if you take the US PR as a standard.
*


I think the need for public outreach is related to the amount of public sway there is over funding science. I'd also venture to say the average educated European has a much better science background than USA folks, so the need to dumb-down presentations to the public is less.

--- mars.gif --- getting back to a concern of mine:

Why does the ESA consider the acidic seas such a barrier to the search for life?
Is it possible to define contraints on the timeframe life could evolve to the more acidic environment? If the early Noachian is the only time that Mars had "ideal" conditions for life to arise, this has two problems:

1. Noachian ended around 3.7 billion years ago(bya); is there enough time between the formation of Mars (4.5 bya?) and the beginning of the Hesparian to allow for life to arise? I think the earliest earth fossils are around 3.5 bya, so life probably got started on earth very close to the end of the Noachian

2. Would heavy bombardment on Mars be much more disruptive than Earth, given it's lesser mass/surface area to dampen effects?

I think there's evidence of green & purple sulphur-loving bacteria on earth in ancient anoxic seas from around 1.6 bya, but I'm not sure how much the Earth's oceans followed the same development paths of Mars. For instance, I think the earliest anoxic oceans on earth (2 bya+) did not have hydrogen sulfide, because banded-iron formations date from this period, but I think they'd be banded pyrite if sulpher was present.

So clearly earth's oceans went through a change around 2 bya that allowed for sufficient buildup of sulphur to support this evolutionary pathway, but could Mars have kept it's seas habitable long enough from the Noachian to allow for its oceans to allow this same pathway?

I guess on earth, life was prolific enough to preserve traces of the sulphur bacteria in oil-bearing carbonate rocks... other than that, I don't know how to look for them.

What are the odds that the dark cobble stones on Meridiani are carbonates? Does anyone know what they are yet, or can I keep my fingers crossed? smile.gif
tty
QUOTE (Marz @ Dec 1 2005, 07:23 PM)
1. Noachian ended around 3.7 billion years ago(bya); is there enough time between the formation of Mars (4.5 bya?) and the beginning of the Hesparian to allow for life to arise?  I think the earliest earth fossils are around 3.5 bya, so life probably got started on earth very close to the end of the Noachian

2. Would heavy bombardment on Mars be much more disruptive than Earth, given it's lesser mass/surface area to dampen effects?

I think there's evidence of green & purple sulphur-loving bacteria on earth in ancient anoxic seas from around 1.6 bya, but I'm not sure how much the Earth's oceans followed the same development paths of Mars.  For instance, I think the earliest anoxic oceans on earth (2 bya+) did not have hydrogen sulfide, because banded-iron formations date from this period, but I think they'd be banded pyrite if sulpher was present. 

So clearly earth's oceans went through a change around 2 bya that allowed for sufficient buildup of sulphur to support this evolutionary pathway, but could Mars have kept it's seas habitable long enough from the Noachian to allow for its oceans to allow this same pathway?

I guess on earth, life was prolific enough to preserve traces of the sulphur bacteria in oil-bearing carbonate rocks... other than that, I don't know how to look for them. 

What are the odds that the dark cobble stones on Meridiani are carbonates?  Does anyone know what they are yet, or can I keep my fingers crossed?  smile.gif
*



All oceans were anoxic up to ca 2 bya ago as proven by the existence of the extensive Banded Iron Formation (BIF) which could only have formed in a virtually oxygenless sea. The BIF may well be due to early photosynthetic organisms using the abundant iron in the sea to get rid of that horrible poisonous oxygen in a safe manner.

There was sulfur in the early ocean too. There is sedimentary pyrite and barite in shallow water facies in the Warrawoona group in Pilbarra from ca 3.5 bya. Whether these are due to the activity of sulfur bacteria is uncertain.

However phylogenetic studies supported by finds of biomarker molecules suggest that Archaea, Bacteria and Eucarya had already separated well before 2,7 bya and that some groups within Archaea (e. g. methanogens) probably had also differentiated by this time.

As for the effect of the Late Heavy Bombardment at 3,8 bya on Mars, who knows?
However if life existed on either Mars or Earth at that time (which seems likely but not certain) and if it could survive the LHB (which is perhaps just possible) the likelihood for transfer between Mars and Earth must have been quite high for a while.

Unfortunately the odds for finding carbonates in Meridiani are not good. No trace of carbonates have ever been found on Mars despite fairly extensive searches from orbit. There probably never was any large amounts of Calcium in martian lakes.

By the way have you read Larry Niven's story "The Green Marauder"? If not I'm not going to give the plot away. Let's just say that it is just about the only science fiction story where the anoxic early oceans of Terra play a central role. wink.gif

tty
paulanderson
QUOTE (Marz @ Dec 1 2005, 09:23 AM)
Why does the ESA consider the acidic seas such a barrier to the search for life?
Is it possible to define contraints on the timeframe life could evolve to the more acidic environment?

What are the odds that the dark cobble stones on Meridiani are carbonates?  Does anyone know what they are yet, or can I keep my fingers crossed?  smile.gif
*

Good questions, and I'd like to see more discussion of these new findings themselves rather than debating the merits of ESA (at least their PR).

I think it is significant that Mars Express has shown there was an earlier wet period of stably present, non-acidic water (re the phyllosilicates / clays), whether in aquifers or seas, etc., even if it was, as some reports now suggest, "cooler and wet" rather than "warmer and wet." This predates the other salty / acidic sulphates known previously and being examined by Opportunity. I think Oppy's findings need to be viewed in context of the new information from Mars Express, which are positive in terms of possible life, as this earlier period was a less acidic, very wet environment. Whether life ever did originate then though in that more limited time period is of course another matter of debate!

This phyllosilicates finding seems to have been overlooked in a lot of the media coverage I've noticed, what I've seen so far anyway (even by science media), while emphasis is placed on the underground ice and crater, which are interesting also of course. As I noted before, too, The JPL side of MARSIS has indicated that the ice patch in the buried crater may even be liquid water, but I haven't seen that reported by anyone other than New Scientist so far.

I saw a mention a few days ago that the cobbles contain basalt (forget just where offhand), but otherwise no other detailed information yet since Squyres said that they were Martian (not meteorites) and unique. Could they contain phyllosilicates? Meridiani is one of the areas where Mars Express found them, according to ESA. I know the larger deposits are some ways from Oppy, but pehaps there could be some smaller bits here and there?
AlexBlackwell
QUOTE (paulanderson @ Dec 1 2005, 06:54 PM)
This phyllosilicates finding seems to have been overlooked in a lot of the media coverage I've noticed, what I've seen so far anyway (even by science media), while emphasis is placed on the underground ice and crater, which are interesting also of course. As I noted before, too, The JPL side of MARSIS has indicated that the ice patch in the buried crater may even be liquid water, but I haven't seen that reported by anyone other than New Scientist so far.

Another MARSIS finding that seems to have been lost in yesterday's blizzard of releases is the apparent lack of a clear indication for basal melting at the north polar cap. The cryospheric models that postulate a recycling of liquid water from polar basal melting towards putative deep seated aquifers in the equatorial regions (thereby serving as reservoirs for the circum-Chryse catastrophic outlfow channels) seem to have suffered.
tty
QUOTE (AlexBlackwell @ Dec 1 2005, 09:16 PM)
Another MARSIS finding that seems to have been lost in yesterday's blizzard of releases is the apparent lack of a clear indication for basal melting at the north polar cap.  The cryospheric models that postulate a recycling of liquid water from polar basal melting towards putative deep seated aquifers in the equatorial regions (thereby serving as reservoirs for the circum-Chryse catastrophic outlfow channels) seem to have suffered.
*


Not necessarily. Even here on Earth some ice-caps are "cold-based", i e frozen to the substratum (the central part of the Scandinavian ice-cap during the last glaciation for example). If there is basal melting on Mars I would expect this to be a cyclic phenomenon. The existence of the layered terrain near the pole is a pretty strong proof of climatic cyclicity by itself.
The best evidence would be the morphology of the surface under the ice-cap. Wet-based ice moves over the substrate and has great erosive power while cold-based ice hardly erodes the substrate at all.
However I'm not sure whether MARSIS has sufficient definition to see e. g. drumlins or tunnel valleys beneath the ice.

tty
helvick
QUOTE (JonClarke @ Nov 30 2005, 10:53 PM)
  Lastly web sites are ephemeral, many journals will not accept web links for precisely this reason, in addition to those above. 
*


+ much very valid comment deleted for brevity.

Yes the web is ephemeral but there is still an enormous benefit to be had from openly publishing scientific material online and early. The archival problem needs to be addressed for stuff that merit but even without that making this stuff available for searching and online cross referencing has an enormous benefit. There is simply too much knowledge out there locked into paper and that needs to change.

I was astonished to read this editorial from Nature. Clearly they are not as locked into the concept of old media as I had thought, my apologies.
JonClarke
QUOTE (helvick @ Dec 1 2005, 10:31 PM)
+ much very valid comment deleted for brevity.

Yes the web is ephemeral but there is still an enormous benefit to be had from openly publishing scientific material online and early. The archival problem needs to be addressed for stuff that merit but even without that making this stuff available for searching and online cross referencing has an enormous benefit. There is simply too much knowledge out there locked into paper and that needs to change.
*


That is why conference abstracts are a such a good idea, they quickly get the information out that would otherwise take months or longer. there have been about a score full ME papers for example, but well over 100 absstracts. These are generally available on line these days, even before the conference.

For the final public study the results still need to be fully and independently reviewed. This can take a year or more. The period between acceptance and actual hard copy can be frustrating, and is longer than anyone would like, but it is hardly critical. the sky isn't going to fall in because a paper becomes available 6 months after the review process is complete, rather than 2 months.

As for paper knowledge being locked away, I disagree. Providing they are catalogued I can access paper knowledge from anywhere in the world within a few weeks. This is much more reliable that a web site which is here today and may be gone tomorow. But then, I am perhaps spoiled by access to an excellent library!

Death of print? Yeah right. We have heard this before.

But we digress from the point, of this thread, which is these amazing results in these two papers and the report on the web site. I really like the image on the ESA site (not in the nature paper) which shows the false colour OMEGA data draped over a 20 m resolution DEM derived from HRSC. you can see the compositional trends in individual beds. There must be a lot more of this stuff in press.

The 20 m HRSC DEM is a very powerful tool. You can drape any data set over it and see what the combination shows. For example, the 3 m resolution MOC images or THEMIS. I saw some nice stuff along these lines at the EGU some 6 months ago, so hopefully this will be coming out soon.

Jon
BruceMoomaw
I thought I remembered some earlier brief mentions of Mars Express finding phyllosilicates. Yep -- there are two abstracts mentioning it from the Septemeber DPS meeting, one of which has a bit more information.
http://www.aas.org/publications/baas/v37n3/dps2005/575.htm :

"The hyperspectral imager OMEGA aboard Mars Express found hydrated minerals in the region of Mawrth Vallis, Mars, by the detection of the 1.9 μm hydration absorption band, caused by the H2O molecule inside the mineral structure. For these hydrated minerals, the combination bands due to the Fe-OH bond at 2.3 μm and the Al-OH bond at 2.2 μm reveal the presence of clay minerals: ferric smectites and montmorillonites (Poulet et al., this conference). HRSC images indicate that the clays correspond to bright outcrops on the plateaus each side of Mawrth Vallis. These plateaus are part of highly cratered Noachian terrain (> 3.7 Gy). On these bright clay rich outcrops, MOC images show light-toned layered deposits, as seen by Malin and Edgett (Science, 2000). The intense wind erosion of these outcrops implies that clays are not only surfacial, but that the bright sedimentary rock itself is made of clays. The observation of such a large amount of clays in this region implies extensive alteration of igneous rocks by water, and the subsequent deposition of clays."

Moreover, it also turns out from the GSA meeting that MER-A has found one rock possibly containing phyllosilicates in the Columbia Hills.
http://gsa.confex.com/gsa/2005AM/finalprog...tract_95505.htm :

" 'Wooly Patch' is an outcrop having unique characteristics, investigated by the Mars Exploration Rover, Spirit, along the rover's traverse to the Columbia Hills. It is the softest rock abraded by the Rock Abrasion Tool at Gusev through sol 291. It shows hardened material at the edges of surface fractures, potentially involving cementation/deposition by fluid. It shows cataclastic texture in the interior matrix and extremely fine porous cuttings. The rock interior has distinct Vis-NIR spectra, and a distinct Mssbauer spectrum with a paucity of Fe2+ in olivine and an intense Fe2+(VI) spectral doublet with parameters slightly different from the pyroxene/glass component within plains basalts. Compositionally, targets on Wooly Patch form the endmembers in three chemical trends of Gusev rocks, and its major silicate-related cation ratios [TC/ICT and ICS/(ICS+ICL)] suggest a medium degree of polymerization (e.g., phyllosilicates). A modified normative calculation based on igneous mineralogy indicates an excess of Al2O3 and SiO2 in its composition. Mass-balance mixing-model calculations suggest phyllosilicates plus remnants of primary basaltic minerals to be the essential constituents that make up this outcrop. Phyllosilicate groups possessing similar cation ratios to those implied by the Wooly Patch analysis spots include the kaolinite, serpentine, chlorite, and septechlorite groups. The potential existence of kaolinite type Al-rich phyllosilicates within the Wooly Patch outcrop suggests a mildly acidic environment (pH from 4 to 6) in the past, and an open hydrologic system."
paulanderson
QUOTE (tty @ Dec 1 2005, 10:52 AM)
Unfortunately the odds for finding carbonates in Meridiani are not good. No trace of carbonates have ever been found on Mars despite fairly extensive searches from orbit. There probably never was any large amounts of Calcium in martian lakes.

Not quite; no large deposits of carbonates have been found yet, but Spirit did find traces, early on. Just traces, but better than none. And low concentrations globally. I remembered this from back in January, 2004:

http://marsrovers.jpl.nasa.gov/newsroom/pr.../20040109a.html

"Traces of carbonate minerals showed up in the rover's first survey of the site with its infrared sensing instrument, called the miniature thermal emission spectrometer or Mini-TES. Carbonates form in the presence of water, but it's too early to tell whether the amounts detected come from interaction with water vapor in Mars' atmosphere or are evidence of a watery local environment in the past, scientists emphasized.

"We came looking for carbonates. We have them. We're going to chase them," said Dr. Phil Christensen of Arizona State University, Tempe, leader of the Mini-TES team. Previous infrared readings from Mars orbit have revealed a low concentration of carbonates distributed globally. Christensen has interpreted that as the result of dust interaction with atmospheric water. First indications are that the carbonate concentration near Spirit may be higher than the Mars global average."

Unless those observations changed later, which I don't recall, then there are at least small amounts, but not none.
Bob Shaw
QUOTE (tty @ Dec 1 2005, 10:49 PM)
Not necessarily. Even here on Earth some ice-caps are "cold-based", i e frozen to the substratum (the central part of the Scandinavian ice-cap during the last glaciation for example). If there is basal melting on Mars I would expect this to be a cyclic phenomenon. The existence of the layered terrain near the pole is a pretty strong proof of climatic cyclicity by itself.
The best evidence would be the morphology of the surface under the ice-cap. Wet-based ice moves over the substrate and has great erosive power while cold-based ice hardly erodes the substrate at all.
However I'm not sure whether MARSIS has sufficient definition to see e. g. drumlins or tunnel valleys beneath the ice.

tty
*



The MARSIS 'image' of the polar cap certainly is low resolution, and yes, the press release seemed quite specific about no meltwater being found (presumably that'd show up really well).

Of more positive interest were the prospects of ancient sub-surface crater remnants in Chryse and their relationship to water deposits.

Bob Shaw
paulanderson
The Sun newspaper in the UK is also saying the ice in the buried crater may be liquid. A very brief article, but they are quoting Professor John Guest of University College:

http://www.thesun.co.uk/article/0,,2-2005550842,00.html

I checked, and yes, John Guest is involved with MARSIS (hadn't heard his name before):

http://www.pparc.ac.uk/mars/bg_i_marsis.asp

I'm curious now; New Scientist and The Sun are quoting two MARSIS scientists, that there may be liquid water in the bottom of that subsurface crater, one in the UK and one in the US (JPL). William Johnson (re New Scientist) is the one at JPL, although Jeffrey Plaut (also with MARSIS at JPL), and Giovanni Picardi (MARSIS, in Italy) have been quoted as saying that no evidence for liquid water had been found yet (ESA press release and BBC News). So are both "liquid water" stories just misquotes, or are there just divided opinions within MARSIS? A misquote would be less likely, I would think, with New Scientist, than with The Sun, so I am thinking there are just various opinions at this point, until MARSIS can take another look.

Of course, as stated also, the main search for liquid water by MARSIS will begin later this winter / spring.
Bob Shaw
QUOTE (paulanderson @ Dec 2 2005, 10:29 PM)
The Sun newspaper in the UK is also saying the ice in the buried crater may be liquid. A very brief article, but they are quoting Professor John Guest of University College...

[
*


FWIW, I've always felt that John Guest came down on the right side of most issues. The Sun 'newspaper', however, is about as reliable as those US supermarket thingies that report Elvis on Pluto - I'd go for a *quality* rubbish UK newspaper any day, like the Daily Sport!

Bob Shaw
paulanderson
Re my contention about making the critical distinction between the clay minerals and sulphates, both part of Mars' water story, Jean-Pierre Bibring, principal investigator for Omega on Mars Express, sums it up nicely in this new BBC News article (December 6, 2005):

http://news.bbc.co.uk/1/hi/sci/tech/4502018.stm

Quotes:

"Crucially, these are not the sulphate minerals seen by the US Mars rovers but a different class of hydrated minerals, known as phyllosilicates - more familiarly called clay minerals. In Bibring's opinion, it is far more likely that ExoMars will find evidence of life laid down in these rocks than if it were to look at the sulphates documented by the US vehicles. "Phyllosilicates trace the moment when liquid water was perennial and persistent - something not necessary to make sulphates. To make clay minerals requires long-standing bodies of water and [for life to form] you need that - at least with the experience we have from Earth." This puts Marwth Vallis and other clay locations - such as Arabia Terra, Terra Meridiani, Syrtis Major, and Nili Fossae - high on the list of possible ExoMars targets. And it pushes down the list the sulphate locations such Meridiani Planum and Gusev Crater currently being inspected by the US Mars rovers. Their sulphates were formed in acidic conditions - a challenging environment for any lifeform to evolve.

It is a point echoed last week by US rover scientist Dr Andrew Knoll of Harvard University. He observed: "Life that had evolved in other places or earlier times on Mars, if any did, might adapt to Meridiani conditions, but the kind of chemical reactions we think were important to giving rise to life on Earth simply could not have happened at Meridiani." Jean-Pierre Bibring says the instruments on ExoMars should be equipped to look for large carbon molecules in amongst the clays of Marwth Vallis as a possible signature of past life."

I'm glad to see at least BBC News and a handful of others are showing both sides of the equation. Daily Planet on Discovery Channel here in Canada also ran a piece yesterday on the new subsurface ice findings by Mars Express, which was good (and I like DP), but no mention yet of the clay mineral findings.
JonClarke
I agree, there is a tendency to draw far reaching conclusions from still minscule sets of data.

What is interesting to me is the increasing complexity of the story, and the diversity of aqueous environments being found.

There is an interesting paper in press with Earth and Planetary Science letters by Tosca and McLennan, on chemical divides in Martian brines (for those who have access) modelled for basaltic weathering There are five major end members suggested, one corresponds closely with what we see at Meridiani, and one with the salts in the Nakhlites.

Jon
BruceMoomaw
Since the ESA -- to my amazement -- seems to be serious about flying ExoMars (maybe serious enough to cancel BepiColombo for it), the obvious question is: should both it AND MSL be sent to phyllosilicate sites, or should one of them be sent to a different type of terrain, such as a Meridiani-type sulfate deposit? (A pretty strong case can be made, actually, that they SHOULD both go to diferent phyllosilicate sites.)
edstrick
Clearly, there needs to be close cooperation between ESA and NASA on picking rover sites. But given that both rovers are (I presume) being designed to go into smaller landing site footprints (that can fit in more complex terrain). As surface mineralogic mapping improves in resolution and mineral discriminability, it will be more and more likely we'll be able to target landing sites with primary target lithologies, like the clay minerals, and secondary targets nearby, perhaps younger sulfate deposits.

Opportunity's landing site is a good example of what would be a TERRIBLE site for an advanced rover. Once Oppy reaches Victoria crater, there's almost nowhere to go. Endless variations on dunes and etched terrain extending far beyond plausible rover traverse distances.

I don't know where the current "Terra Meridiani" deposits of phyllosilicates are, but one possibility might be the far northeast edge of Meridiani Sinus, where some of the fantastically etched multi-layered deposits of the "meridiani badlands" are being stripped off of old cratered terrain. If so, you could explore some of the old terrain's geology, and a fantastically better exposed sample of the younger deposits. (The old terrain's exposures might not be nearly as well "opened up" as in channels or chaotic terrain, though.)
BruceMoomaw
Well, keep in mind that the central goal of Martian exploration is still finding promising possible fossil beds -- and ancient clays from nonacidic water are the best candidate yet: much better than acid-produced sulfates. As Doug McCuistion said at the COMPLEX meeting, the strategy of trying to close in on the best places to look for Martian fossils as our top goal is producing huge amounts of non-biological scientific data about Mars as a side benefit -- whereas the reverse would not be true. (The major exceptions seem to be atmospheric studies and seismology, both of which are given an improved place in the latest NASA plan.)
gpurcell
QUOTE (BruceMoomaw @ Dec 7 2005, 07:37 AM)
Since the ESA -- to my amazement -- seems to be serious about flying ExoMars (maybe serious enough to cancel BepiColombo for it), the obvious question is: should both it AND MSL be sent to phyllosilicate sites, or should one of them be sent to a different type of terrain, such as a Meridiani-type sulfate deposit?  (A pretty strong case can be made, actually, that they SHOULD both go to diferent phyllosilicate sites.)
*



So that's the deal, then? I was reading the Bepi cancellation as evidence that ESA science was going to be slowly strangled....
ljk4-1
If they want to put human colonies on Mars, perhaps they should have rovers that focus on what resources are available to help them build structures and "live off the land" if possible.

http://www.marshome.org/building-the-base/

Then once a base or two are established, they can send out teams of geologists/paleontologists to look for fossils.
RNeuhaus
QUOTE (BruceMoomaw @ Dec 7 2005, 08:58 AM)
Well, keep in mind that the central goal of Martian exploration is still finding promising possible fossil beds.
*

Only fossil? but also for the actual habits or not? Under the appropiate sub-surface where any lichen might be waiting for our visit...

Rodolfo
AlexBlackwell
QUOTE (tty @ Dec 1 2005, 09:49 PM)
Not necessarily. Even here on Earth some ice-caps are "cold-based", i e frozen to the substratum (the central part of the Scandinavian ice-cap during the last glaciation for example). If there is basal melting on Mars I would expect this to be a cyclic phenomenon. The existence of the layered terrain near the pole is a pretty strong proof of climatic cyclicity by itself.

The "cyclical, cold-based" model you outline above is certainly plausible, especially given that orbital forcing undoubtedly plays a critical role in Mars' ice ages; however, given that Mars' current obliquity is about intermediate in the cycle, I would presume the current basal load would support detectable melt.

QUOTE (tty @ Dec 1 2005, 09:49 PM)
The best evidence would be the morphology of the surface under the ice-cap. Wet-based ice moves over the substrate and has great erosive power while cold-based ice hardly erodes the substrate at all.
However I'm not sure whether MARSIS has sufficient definition to see e. g. drumlins or tunnel valleys beneath the ice.
*

It's early days but I, too, suspect that MARSIS, even with longer integration period and repeat coverage over the northern polar cap, may lack the ability to resolve any remnant structure indicating a basal melt flow towards the equatorial regions.
JonClarke
QUOTE (BruceMoomaw @ Dec 7 2005, 07:37 AM)
Since the ESA -- to my amazement -- seems to be serious about flying ExoMars (maybe serious enough to cancel BepiColombo for it), the obvious question is: should both it AND MSL be sent to phyllosilicate sites, or should one of them be sent to a different type of terrain, such as a Meridiani-type sulfate deposit?  (A pretty strong case can be made, actually, that they SHOULD both go to diferent phyllosilicate sites.)
*


I don't think there can be any dount that ExoMars has been a very serious and strong contender of a future Mars mission for quite some time. So it is good that it looks like full funding has now been confirmed through 2011.

The phillosilicate sites are as follows:

1. Isemenius Lacus slightly rougher at MOC scale than the MER sites, rare mesas, fairly featureless 34.0 N

2. Syrtis Major site somewhat rougher at all scales compared to equivalent imagery of MER sites, lots of rampart craters, diversity of surface geological units, channel-like feature, 19.91 degrees N

3. Mwarth Vallis site much rougher at all scales compared to equivalent imagery of MER sites, diversity of surface geological units, distinct channel-like feature, 24.54 N

4. Nili Fossae site very much rougher at all scales compared to equivalent imagery of MER sites, diversity of surface geological units, rift-like features, mesas, dunes, possible fans 24.54 N

As you would expect, the more interesting the site the rougher the topography. I would suggest that site 2 is a good compromise although i would like 3 or 4. A lot depends on the nature of the landing system as to how rough a site it can land in, both in respect to small scale surface roughness and hazard avoidance. All of these sites are within the 45 degrees N or S of the equator limits specified by ExoMars.

Opportunity went to Merdiani in search of haematite and found sulphate as the big item. ExoMars will go to Syrtis (or wherever) and will find ?????

Jon
JonClarke
QUOTE (gpurcell @ Dec 7 2005, 02:10 PM)
So that's the deal, then?  I was reading the Bepi cancellation as evidence that ESA science was going to be slowly strangled....
*


ExoMars is funded out of the Aurora, not the science budget. As I understand, science funding is based on per capita ESA-wide contributions wheras Aurora projects by project-specific funding from individual nations.

Two recent BBC stories:

http://news.bbc.co.uk/2/hi/science/nature/4503680.stm

http://news.bbc.co.uk/2/hi/science/nature/4507122.stm

Jon
RNeuhaus
The above 4 mentioned sites of interest for ExoMars since they have high probability to find phillosilicate. All of those terrain are rough, covered with stones like the Viking 1 and 2 sites. On the other hand, David Parker, David Parker, director of space science at the British National Space Centre, said the mission would build on the heritage of Beagle 2.

"Imagine a spacecraft landing on Mars using parachutes and airbags, maybe a rocket system of some sort," he told the BBC News website.

Hope it won't be a repeated mistake. No airbag on these rough sites unless use only rockets and an advanced surface radar and navigation autonomy system to steer the wrong landing place for one better surface to land like the ones of the american landing mode with Skycrane . If MSL success its landing, hope that ESA will follow it.

Rodolfo
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