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New Mars Express And Huygens Results, ESA conference - November 30, 2005
Guest_AlexBlackwell_*
post Nov 30 2005, 06:46 PM
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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).
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mike
post Nov 30 2005, 08:22 PM
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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?
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elakdawalla
post Nov 30 2005, 08:33 PM
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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.

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helvick
post Nov 30 2005, 08:46 PM
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QUOTE (mike @ Nov 30 2005, 09:22 PM)
Why don't these science teams just self-publish the data on some website they control?
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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.
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JonClarke
post Nov 30 2005, 09:53 PM
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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
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mcaplinger
post Nov 30 2005, 10:45 PM
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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


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Phil Stooke
post Dec 1 2005, 03:57 AM
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mcaplinger said:

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

They dost nowt!

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Guest_paulanderson_*
post Dec 1 2005, 04:30 AM
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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.
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JonClarke
post Dec 1 2005, 08:01 AM
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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
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Rakhir
post Dec 1 2005, 03:20 PM
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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
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RNeuhaus
post Dec 1 2005, 04:48 PM
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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
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Marz
post Dec 1 2005, 05:23 PM
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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
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tty
post Dec 1 2005, 06:52 PM
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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
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Guest_paulanderson_*
post Dec 1 2005, 06:54 PM
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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?
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Guest_AlexBlackwell_*
post Dec 1 2005, 07:16 PM
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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.

This post has been edited by AlexBlackwell: Dec 1 2005, 08:08 PM
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