More results for the possibility of Life on Mars - Page 3

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LWS


Posts: 3062

Reply: 41



PostPosted: September 13, 2010 8:21 AM 

Hi Kye; Thanks for the link in reply #40
Winston

Barsoomer


Posts: 344

Reply: 42



PostPosted: September 13, 2010 11:00 AM 

[link]

More on reinterpreted Viking results by Navarro-González et al.

Barsoomer


Posts: 344

Reply: 43



PostPosted: September 13, 2010 3:49 PM 

link

More detailed summary by science writer Ron Cowen for Science News (www.sciencenews.org) of the Viking reinterpretation.paper by Navarro-González et al.

Key points:

* The authors simulated the Viking experiments with perchlorate added, and found chloromethane and dichloromethane as the only organic compounds detected. These were also detected by Viking, but were attributed to contamination from Earth.
* The paper estimates there actually were a few parts per million of of organics in the soil tested by Viking.

* Given the reinterpreted organic detection, a new life test experiment such as DNA detection is recommended for a future Mars probe.

I assume the DNA test could use the polymerase chain reaction (PCR), which is extremely sensitive for detecting DNA fragments.

Barsoomer


Posts: 344

Reply: 44



PostPosted: September 13, 2010 5:09 PM 

I had forgotten that reply 11 by Horton on Sep 4 also described this paper.

Sorry if this is rehashing old news, but the Ron Cowen account gives the additional detail that the new paper is able to estimate (from the chloromethane and dichloromethane detection by Viking) the amount of organic carbon at the Viking sites as a few parts per million.

LWS


Posts: 3062

Reply: 45



PostPosted: September 13, 2010 9:02 PM 

Barsoomer; Glad to see that someone besides myself forgets info in some of these posts. However, the info is important enough to bear repetition.

I think that if someone collates all the bits and pieces of information coming out over the last 2 years or so that suggests that there is life on or near the surface of Mars that the balance of the available evidence would surprise our local sceptics like dx and ben.

Winston

dx


Posts: 1661

Reply: 46



PostPosted: September 13, 2010 10:38 PM 

LWS>>>

LOLOLOLOL

yt
dx
Wink

Serpens


Posts: 169

Reply: 47



PostPosted: September 15, 2010 12:10 AM 

Winston, the 2005 paper ‘Chemistry and mineralogy of outcrops at Meridiani Planum’ by Clark, McLennan, Tosca, Squires et al stated that the Cl enrichment at the Martian surface and the highly oxidising condition evidenced by the strong photochemically generated oxidants in the atmosphere meant that the presence of chlorites, chlorates and perchlorates, in particular Magnesium perchlorate should be considered. So perhaps the identification of perchlorates at the Phoenix site was not completely unexpected?

Organics do not mean life, and there should be a wealth of organic compounds at the Martian surface from the infall of carbonaceous chondrites. But the oxidising power of these highly soluble compounds would tend to supress organics in the regolith. And in your considerations of the ‘bits and pieces of information’ do you accept that that the presence of a strong oxidising agent like a perchlorate could well have created a false positive in the Viking LR experiment?

LWS


Posts: 3062

Reply: 48



PostPosted: September 15, 2010 8:41 AM 

Serpens;

Yes

Barsoomer


Posts: 344

Reply: 49



PostPosted: September 15, 2010 11:08 AM 

Perchlorate is very stable at low temperatures; it is only when it is heated that it becomes a powerful oxidant. From Wikipedia:

"The perchlorate ion is the least reactive oxidizer of the generalized chlorates. This is apparently paradoxical, since higher oxidation numbers are expected to be progressively stronger oxidizers, and less stable. Perchlorate does in fact have the highest redox potential and is least stable thermodynamically, but the central chlorine is a closed shell atom and well protected by the four oxygens. Hence, perchlorate reacts sluggishly."

However, magnesium perchlorate generates heat when added to water, which did occur in the LR experiment, so maybe that explains the result. Someone should replicate that experiment with magnesium perchlorate to see if the observed results in the LR experiment can be duplicated.

Given the current cold and dry conditions on Mars, it seems unlikely that magnesium perchlorate would be destructive to organics in the regolith.

Serpens


Posts: 169

Reply: 50



PostPosted: September 19, 2010 8:21 PM 

Barsoomer, the idea that the minute trace organics detected were not attributable to the cleaning of the instruments but were remnants of martian organics destroyed by heating perchlorates in the sample could perhaps be feasible if it were not for the fact that they have the same Cl isotope ratios as Earth. Bit of a stretch there.

The other thing to consider is the potential precursors that could be involved in perchlorate formation and the impact of these on organics.

Serpens


Posts: 169

Reply: 51



PostPosted: September 20, 2010 12:35 AM 

Barsoomer. Not so. The 'blank test' did indeed detect organic residue and the GC peaks in the subsequent soil analysis profile corresponded to the cleaning solvent blank baseline. See the link to the American Society of Mass Spectrometry conference poster.

http://www.asms.org/Portals/0/Viking_Poster_Main.pdf

Quoting 'Surprisingly no organic materials could be detected, other than the contaminating solvent traces already observed during the "cruise blank". To improve the search, each mass chromatogram, from m/z 12 to m/z 215 was carefully examined for maxima, but no coinciding set could be found (except for the solvent contaminants), indicating the absence of indigenous organic compounds at a sub part per billion detection limit'.

The inference is of course that there were insufficient organics at the Viking site to affect the change the baselined profile line structure position and intensity (maxima). So perchlorates + organics + heat can create the traces identified by Chris McKay et al. But in the absence of organics the Viking soild analysis results would reflect the blank baseline - which they did.

Serpens


Posts: xxx

Reply: 52



PostPosted: September 20, 2010 5:57 AM 

Ahh my last post was a response to Barsoomer's post 51 which has now disappeared? It was not in the least bit contentious so I assume that this was not random censorship?

hortonheardawho


Posts: 3465

Reply: 53



PostPosted: September 20, 2010 10:12 AM 

Ooops. Sorry serpens, I deleted reply 51. I got an e-mail from Barsoomer ( sent 12:37 ) requesting that the post be deleted. I would not have deleted the post had I seen that you had already replied.

As a result I have decided not to honor any request for post deletion.

Again, sorry about that.

Barsoomer


Posts: 344

Reply: 54



PostPosted: September 20, 2010 10:48 AM 

Shortly after posting, I asked for it to be removed due to a confusion on my part. I had just seen the poster you linked to (before you posted it).

Kevin Author Profile Page



Posts: no

Reply: 55



PostPosted: September 22, 2010 5:26 AM 

Plants thriving in harsh conditions at Chernobyl.

http://www.bbc.co.uk/news/science-environment-11345935

dx


Posts: 1661

Reply: 56



PostPosted: September 22, 2010 9:45 AM 

folks>>>

http://www.sciencedaily.com/releases/2010/09/100915094346.htm

Here is a good read with respect to Earth life that apparently never took hold on Mars. Its very simple to understand the process of transformation of water plants to land plants then again those early near shore animals taking the first bite of land greenery and scooting back into the ponds or other water masses for refuge. Obviously those early effects of transformation made the Earth as we know it. You can't say the same thing for Mars. But for the doubters, we can discover WHY Martian life never took hold, that would be an interesting and obvious answer.

Of course millions of years blasted by for these worldly changes to take effect on Earth to make the whole story-give or take a few missing parts-we know well enough today.

Earth, wonderful place we live on, why would anyone want to waste money life and limb to go to a deadly, inhospitable and lifeless planet like Mars? Its not logical.

Now, Ceres is just around the corner!

yt
dx
Wink

Barsoomer


Posts: 344

Reply: 57



PostPosted: September 22, 2010 11:42 AM 

http://www.astrobio.net/pressrelease/3623/mars-methane-lasts-less-than-a-year

More about methane.

ben


Posts: 2270

Reply: 58



PostPosted: September 22, 2010 1:24 PM 

Thanks DX for your reply #55.
I think it reinforces my ideas presented earlier about lack of advanced plant life on Mars.

Though there may be microbes on Mars (and probably most rocky bodies) lack of critical circumstances has prevented the evolutionary pattern for life as we know it.

ben


Posts: 57

Reply: 59



PostPosted: September 28, 2010 9:44 PM 

I too believe that life is more widespread in the Cosmos than we generally accept. The vast bulk of earth's biomass is composed of microbes and basic simple lifeforms. So even the comparatively benign conditions on earth limits the range of higher order species. Therefore the best we can hope for on most planents especially those with harsher conditions are some limited range of basic organisms. Nevertheless when we do eventually find some it will be yet another giant step forward and cause us to seriously re-evaluate our future. Right now the evidence remains unproven, I am sure in due course it will change.

Remember when I was growing up in the sixties we suspected that extra-solar planets might exist but there was no proof. In the last twenty years it has changed and an immense number of planents (mainly gas giants) have been located. I firmly expect the position concerning life will changes also. When it happens my first question is going to be is it DNA based, if it isn't then that will throw open a whole range of new areas for study.

Kevin Author Profile Page



Posts: no

Reply: 60



PostPosted: September 30, 2010 4:43 AM 

New Exo Planet found in the "Goldilocks Zone" it's 3 times the mass of Earth and its gravity could be strong enough to hold water on or near the surface. It might be Habitable.

[link]

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