Mount Sharp Extended mission 1a - Page 13

Previous 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 Next
Author Message
marsman


Posts: 303

Reply: 241



PostPosted: September 9, 2017 6:33 PM 

Winston,

Here is an interesting article to read on sulfur-based life (phosphate not required):

http://www.americaspace.com/2016/02/02/cauliflower-silica-formations-on-mars-evidence-of-ancient-life/

My guess/speculation would be that the Mars cauliflower silica formations utilize sulfur in their formation, instead of carbon.

/R

marsman

marsman


Posts: 303

Reply: 242



PostPosted: September 9, 2017 6:56 PM 

Here is the corrected article link:

https://cosmosmagazine.com/chemistry/life-without-phosphate-mystery-solved

/R

marsman

marsman


Posts: 303

Reply: 243



PostPosted: September 9, 2017 7:01 PM 

Here is the corrected article link:

https://cosmosmagazine.com/chemistry/life-without-phosphate-mystery-solved

If this is a duplicate post, then please delete.

/R

marsman

marsman


Posts: 303

Reply: 244



PostPosted: September 9, 2017 7:46 PM 

Biochemical 'fossil' shows how life may have emerged without phosphate for a phosphate-free sulfur-based core biology:

https://www.sciencedaily.com/releases/2017/03/170302133445.htm

/R

marsman

John Radogno


Posts: 37

Reply: 245



PostPosted: September 10, 2017 2:11 AM 

Test

John Radogno


Posts: xxx

Reply: 246



PostPosted: September 10, 2017 11:59 AM 

Marsman, thanks for the link. Here is the picture that goes with it:

Barsoomer


Posts: 344

Reply: 247



PostPosted: September 14, 2017 5:48 PM 

https://www.youtube.com/watch?v=YMjxC7UNiT4

Youtube presentation by John Grotzinger, former project scientist on Curiosity Mission, to the Mars Society annual convention.

He mentions that they had to promise the NASA Planetary Protection office that they would stay away from any site that contained ice or water, and if they accidentally stumbled on such, they would drive away as quickly as possible! After the talk Zubrin makes some editorial remarks criticizing this policy.

Given that NASA is considering a Mars sample return mission in the 2020s, I think it is imperative that they give priority to protecting Earth from Mars organisms rather than protecting Mars from Earth organisms.

This means that they need to focus on exploring whether Mars has current life even if this risks local contamination of Mars with Earth life.

John Radogno


Posts: 37

Reply: 248



PostPosted: September 14, 2017 11:20 PM 

I agree that this is a two way street. It is probably better to wait another ten years or so for better technology to assure both planets are safe. The fact that there is so much concern about still active microbes from Earth on the Curiosity rover says a lot.

LWS


Posts: xxx

Reply: 249



PostPosted: September 15, 2017 8:16 AM 

John Radogna;

Re your reply $248, would you like to spell it out. My take is that they have overwhelming evidence that ice and water and current microbial Martian life exists on Mars. If they didn't then there would be no need for the over protection of what many of the scientists project as an impossible surface biota on Mars.

I think that many images, especially by Curriosity, show that ancient microbialites exist there. Who knows what else is beneath the surface? The sensible overweening concern must be ensuring that there is an infinitesimal probability that viable hitch hikers can contaminate a sample return project.

Winston

LWS


Posts: xxx

Reply: 250



PostPosted: September 15, 2017 11:38 PM 

Here's a crop of a Gimp auto White balanced treatment of a sol 1797 landscape that shows a remarkable structure at the bottom of the picture in overall symmetry, colour, etc. Several such structures were visible from afar from the early days of the Curi odyssey but this is the first time I've seen one up close.

Hope they get some other images to clarify and perhaps heighten the symmetry.

Winston

John Radogno


Posts: xxx

Reply: 251



PostPosted: September 17, 2017 1:19 PM 

Winston, Re: #249 & #248
When we refer to "they" we are talking about the Curiosity team of scientists as well as an international well of professional researchers. Yes they do have overwhelming evidence of ice and water on Mars. They have a lot of evidence that microbes may have existed in the past (things we have been looking at for years). They have a lot of evidence that live microbes can exist on Mars (in addition to any carried over on Curiosity), but they do not have overwhelming evidence that active Mars' microbes currently exist, and that is what they need to make the call. That will take some better rovers of a return mission to be able to say
for sure. I expect that sooner or late the evidence will be found. If there is a possibility of earth microbes contaminating any Mar's samples it will only prolong the ultimate proof of life and that alone is a good reason for being careful.
If we find active microbes in say a recurring lineae slope, or another kind of micro-pocket habitable environment, surely the indigenous microbes would be at risk of extinction.
There is some debate going on right now as to wether Earth microbes on Curiosity have died off, or wether they may become re-activated if they were introduced to into a micro-environment that supported indigenous microbes.

John Radogno


Posts: xxx

Reply: 252



PostPosted: September 17, 2017 5:09 PM 

Winston, Re: #250
I think this is a small mesa, a last remnant of what was once a larger plateau that covered this part of Mt. Sharp at some ancient time. The fallout skirt is actually not symmetrical but it is not surprising that it is close, as that is what we often see in similar structures.
I am wondering if this mesa/butte is tipped off with hematite, a more resistant iron-oxide material. Curiosity is not far off from Vera Ruby Ridge in which orbital spectrometer observations have found a much stronger presence of hematite than other locations that Curiosity has found.
Here are some examples:


Notice that if we did not have an arial view, we would not know that the mesa has a very irregular shape on its' back side.



The skirt on this one below is almost symmetrical:

I think the processes that build up the skirts are all similar with the exception that on Mars the process takes much, much longer for obvious reasons.

LWS


Posts: xxx

Reply: 253



PostPosted: September 17, 2017 5:34 PM 

John;

Very interesting comments in your reply #251.

If one wants to develop a probability for Earth Microbes becoming putative invasive species on Mars one might first look at the examples of invasive species on Earth moving from a benign tropical environment or microclimate into a very harsh arctic or temperate one here. On Earth, there are several examples of invasive species moving between fairly similar microclimates or microenvironments. Indeed, such species are generally classed as Quarantine pests. However there are few examples of such pests moving from say, the tropics to temperate climates, or vice versa, and surviving. Indeed, the use of the Pest Risk Analysis (PRA) tool is partially based on the low probability of such movements.

Indeed, one might use the PRA principles to get some feel for the likelihood of a few earth microbes, having survived the interplanetary flight between Earth and Mars, finding the precise microclimatic conditions on the harsh surface of Mars that would allow them to exist at a stage where they could become a threat to putative organisms on Mars.

You said "If we find active microbes in say a recurring lineae slope, or another kind of micro-pocket habitable environment, surely the indigenous microbes would be at risk of extinction. ". I'm not so sure.

It seems counterintuitive to expect that a newly arrived organism would be capable of out-performing a greater mass of indigenous ones that would have thrived in the martian harsh environment for perhaps billions of years and would have done so through myriad genetic modifications over the eons.

If we accept the results of Gil Levin's LR tests they appear to show that under the conditions of the LR environments, microbes (similar to ours) quickly metabolized nutrients in an aqueous medium before they stopped. This test was replicated with the same results at 2 different sites suggesting that the putative martian microbes which reacted might be reasonably widespread over the martian surface.

That possible ubiquity alone suggests that a few hitch hiker microbes on a mars probe that has been as thoroughly cleaned as possible, would suffer from significant competition by indigenous species and would be therefore unlikely to have a significant spread potential and thereby be unlikely to be invasive.

A sample return trip would be however replete with problems. Here the Pest Risk analysis would result in an unacceptably high figure that would necessitate Management of an extremely expensive nature on a satellite or the Moon to accurately determine the viability and competitiveness of any microbes that might have been inadvertently contained in the samples before the samples are brought anywhere onto Earth.

Winston.

LWS


Posts: xxx

Reply: 254



PostPosted: September 17, 2017 5:42 PM 

John;

Re. your reply #252, I can only say, Great!! I was looking for pictures like the ones you posted but only found a few, none of which were as relevant to the martian ones as yours above.

I thought it was a mesa (I actually named the image "mesa")

Thanks!

Winston

LWS


Posts: xxx

Reply: 255



PostPosted: September 17, 2017 6:24 PM 

John;

I forgot to mention above that, despite the numerous novels, etc,. that say otherwise, it is extremely difficult to create an artificial epidemic. Thus attempts to infect journalists and others with non-weaponized anthrax were unsuccessful and many Plant pathologists will tell you that it is not easy to grow some spores and merely spray them on susceptible plants and successfully start far less spread an epidemic. The spread and establishment of many microbes

We obviously have to be super super careful to stop the spread of possible microbes from Mars but I am not so sure of the probability of establishment and spread in the opposite direction.

Winston

Barsoomer


Posts: 344

Reply: 256



PostPosted: September 17, 2017 7:29 PM 

We should be able to readily distinguish living Mars organisms from Earth contamination. All we have to do is sequence the DNA. Even if the organisms are very similar there should be vast differences in the non-coding part of the DNA due to random mutations.

If it is not-life-as-we-know-it, it should be even easier to conclude its non-earthly origin.

It would be much harder to tell with dead organisms where the DNA has been destroyed. So I think looking for ancient life is a non-productive use of scarce resources.

John Radogno


Posts: 37

Reply: 257



PostPosted: September 17, 2017 7:55 PM 

Finding unique DNA, possibly with a different collection of amino acids would be enormously valuable to who ever finds it.

LWS


Posts: xxx

Reply: 258



PostPosted: September 19, 2017 11:08 PM 

http://www.satun-geopark.com/en/%E0%B9%81%E0%B8%AB%E0%B8%A5%E0%B9%88%E0%B8%87%E0%B8%97%E0%B9%88%E0%B8%AD%E0%B8%87%E0%B9%80%E0%B8%97%E0%B8%B5%E0%B9%88%E0%B8%A2%E0%B8%A7%E0%B9%80%E0%B8%9E%E0%B8%B7%E0%B9%88%E0%B8%AD%E0%B8%81%E0%B8%B2/tha-rae-stromatolitic-rocks/

Winston

Faceless


Posts: 24

Reply: 259



PostPosted: September 20, 2017 12:41 AM 

Re 258, very nice find.

Barsoomer


Posts: 344

Reply: 260



PostPosted: September 20, 2017 9:01 PM 

Very nice, indeed.

In other news, enhancements of the neutron spectrometer data from Mars Odyssey seem to be showing large amounts of hydrogen (signifying water) in the vicinity of the RSLs.

[link]

The amounts seem too large to be explained by absorption from the atmosphere and may indicate buried ice---near the equator!

Previous 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 Next


Join the conversation:















Very Happy Smile Sad Surprised
Shocked Confused Cool Laughing
Mad Razz Embarassed Crying or Very Sad
Evil or Very Mad Twisted Evil Rolling Eyes Wink
Powered by MTSmileys