Levin going a bit too far in his zealotry?

[Grizzly]

I've a lot of respect for Gilbert Levin and his work, but I wonder if he might be pushing things a bit too far with his latest claims about life on Mars.

Space.com article here

I know, I know, it's hard to restrain oneself when faced with the wealth of data coming back from Mars, but these experiments are not designed to make the determination as to whether what we are seeing is, in fact, water. And it's a leap between water and life...

He's not being heard, except by the woo-woo fringe now.

----
LUKE SUM IPSE PATREM TE
Luke, I am your father.

[ToSeek]

If there were water, couldn't the rovers detect it?

[Daffy]

If there were water, couldn't the rovers detect it?

Only if it were in their vicinity. I don't think anyone is suggesting it is everywhere.

[RGClark]

I've a lot of respect for Gilbert Levin and his work, but I wonder if he might be pushing things a bit too far with his latest claims about life on Mars.

Space.com article here

I know, I know, it's hard to restrain oneself when faced with the wealth of data coming back from Mars, but these experiments are not designed to make the determination as to whether what we are seeing is, in fact, water. And it's a leap between water and life...

He's not being heard, except by the woo-woo fringe now.

----
LUKE SUM IPSE PATREM TE
Luke, I am your father.

It is no different than what he has always been saying. I don't see why you would say he going to far *now*, as oppposed to before.

This article shows Mars and extremophile expert Penny Boston is taking seriously the idea that life currently exists on Mars:

Posted 8/3/2004 4:56 AM
Researchers: Water could mean Mars hills were alive
The Associated Press
"These hills might date back to some of the earliest history on Mars," said Larry Crumpler, a Mars Exploration Rover team member and curator at the New Mexico Museum of Natural History and Science. "It looks like a river channel might have flowed through there. In fact, the case is building that lots of standing water — streams, maybe ponds, existed in the planet's history."
"Water is important to Crumpler and fellow scientists because it indicates life might have evolved on the planet.
"If so, it was most likely microscopic. But still, the idea is thrilling, said Penny Boston, a planetary scientist and Mars expert at New Mexico Tech in Socorro.
"Is there a chance that life still exists on Mars? I sure hope so," Boston said.
"With the new evidence of water, she thinks there is about a one-in-three chance that life still exists — based on estimates that are part faith and supposition and part science. "If you asked me that 10 years ago, though, I would have said one in 100," she added."
http://www.usatoday.com/tech/news/20...rs-hills_x.htm

More on Dr. Boston's research:

Life in the Extremes: An Interview With Dr. Penelope Boston.
http://www.ibiblio.org/astrobiology/...ge=interview09



Bob Clark

[ToSeek]

If there were water, couldn't the rovers detect it?

Only if it were in their vicinity. I don't think anyone is suggesting it is everywhere.

Levin seems to be suggesting that the rovers are driving across moist soil. You'd think one of the instruments like the mini-TES could detect water.

[Demigrog]

If there were water, couldn't the rovers detect it?

Only if it were in their vicinity. I don't think anyone is suggesting it is everywhere.

Levin seems to be suggesting that the rovers are driving across moist soil. You'd think one of the instruments like the mini-TES could detect water.

Not to mention that if there was anything approaching surface water or frost, you'd better believe NASA would be holding a press conference (especially with their budget under review as we speak). I'd say NASA was holding back until they were 100% sure, but Levin was making these claims months ago.

[Grizzly]

See... I don't think that they can discern that. I thought that the question had been raised earlier in Opportunity's mission when the white substance was dredged up by one of the trenching exercises.

IIRC the trenches were Mossbauered (is that even a word?) and mini-tessed and signatures of salts were discovered. The question was raised as to whether it was brine or not and the response was (I thought) that there was no way of telling with the equipment.

Perhpas I'm wrong in that.

True, the pictures do raise some interesting questions - frost from mositure released by the digging, RATting and pressure. But to make the conjecture that there's water that close is unsupported and perhaps unsupportable by the scientific equipment on board. Or am I wrong?

For the record, I'm inclined to believe that Levin's experiments may have discovered life. But until we have a probe on site with sophisticated enough experiments, I'm going to have to be a doubting Thomas.

----
Me dilectissima! Farrago thunni!
My favourite! Tuna-noodle casserole!

[Alpha_Tauri]

IIRC the trenches were Mossbauered (is that even a word?) and mini-tessed and signatures of salts were discovered. The question was raised as to whether it was brine or not and the response was (I thought) that there was no way of telling with the equipment.

The Mini TES is fully capable of detecting frost or any free water or brine on the surface of Mars. Free water would appear on the TES spectra as a peak at 1640cm-1. The paper by Gilbert Levin is so badly flawed that it would be laughable if it were not so sad. The sad part is that some of the general public are taking it seriously.

It totally misses the point that water is unstable on the Martian surface. The following peer reviewed paper discusses the question of the stability of water on a much more rigorous basis:

http://www.agu.org/pubs/pip/2004JE002367.pdf

"While the total surface pressure on Mars is near 610kPa, the triple point vapor pressure is defined in terms of the water vapor partial pressure and thus contraray to popular perception, liquid water is far from stable on Mars) in fact, it is incorrect to state that the Martian environment is close to the triple point for water - It is not)."

It then goes on to explain how ephemeral transient monofilms of water may be possible under very special conditions on the Martian surface, for example under a protective ice sheet capable of trapping vapour and allowing the pressure to build.

All of these cases are transient, and depend on recharge of water.

[Grizzly]

7 months is a looong time. I wondered who'd taken my user name.

----
Nunc dimittis
Let thy servant depart in peace...

[ToSeek]

IIRC the trenches were Mossbauered (is that even a word?) and mini-tessed and signatures of salts were discovered. The question was raised as to whether it was brine or not and the response was (I thought) that there was no way of telling with the equipment.

The Mini TES is fully capable of detecting frost or any free water or brine on the surface of Mars. Free water would appear on the TES spectra as a peak at 1640cm-1. The paper by Gilbert Levin is so badly flawed that it would be laughable if it were not so sad. The sad part is that some of the general public are taking it seriously.

It totally misses the point that water is unstable on the Martian surface. The following peer reviewed paper discusses the question of the stability of water on a much more rigorous basis:

http://www.agu.org/pubs/pip/2004JE002367.pdf

The paper seems to be talking about pure water (correct me if I'm wrong), but what about brine?

[RGClark]

If there were water, couldn't the rovers detect it?

Only if it were in their vicinity. I don't think anyone is suggesting it is everywhere.

Levin seems to be suggesting that the rovers are driving across moist soil. You'd think one of the instruments like the mini-TES could detect water.

Not to mention that if there was anything approaching surface water or frost, you'd better believe NASA would be holding a press conference (especially with their budget under review as we speak). I'd say NASA was holding back until they were 100% sure, but Levin was making these claims months ago.

Now Opportunity HAS detected surface frost at least on the landers.

Next question?


Bob Clark

[RGClark]

IIRC the trenches were Mossbauered (is that even a word?) and mini-tessed and signatures of salts were discovered. The question was raised as to whether it was brine or not and the response was (I thought) that there was no way of telling with the equipment.

The Mini TES is fully capable of detecting frost or any free water or brine on the surface of Mars. Free water would appear on the TES spectra as a peak at 1640cm-1. The paper by Gilbert Levin is so badly flawed that it would be laughable if it were not so sad. The sad part is that some of the general public are taking it seriously.

It totally misses the point that water is unstable on the Martian surface. The following peer reviewed paper discusses the question of the stability of water on a much more rigorous basis:

http://www.agu.org/pubs/pip/2004JE002367.pdf

"While the total surface pressure on Mars is near 610kPa, the triple point vapor pressure is defined in terms of the water vapor partial pressure and thus contraray to popular perception, liquid water is far from stable on Mars) in fact, it is incorrect to state that the Martian environment is close to the triple point for water - It is not)."

It then goes on to explain how ephemeral transient monofilms of water may be possible under very special conditions on the Martian surface, for example under a protective ice sheet capable of trapping vapour and allowing the pressure to build.

All of these cases are transient, and depend on recharge of water.

Levin is aware that liquid water on the surface would eventually evaporate. His point is that microorganisms could survive on liquid water available for only minutes in a day, and then go into a long suspended date during the period when conditions are too cold.
Experiments have shown that liquid water can exist from minutes to hours on the Martian surface:

==============================*=======
Office of University Relations
University of Arkansas


CONTACT:
Derek Sears
Professor, chemistry and biochemistry, Fulbright College;
Director, Arkansas-Oklahoma Center for Space and Planetary Sciences
(479) 575-5204, dse...@uark.edu


Melissa Blouin
Science and research communications manager
(479) 575-5555, blo...@uark.edu


EMBARGOED FOR RELEASE AT 2 P.M. WEDNESDAY, SEPTEMBER 3, 2003


SURFACE WATER POSSIBLE UNDER MARS-LIKE CONDITIONS


FAYETTEVILLE, Ark. -- A team of researchers from the University of
Arkansas has measured water evaporation rates under Mars-like
conditions, and their findings favor the presence of surface water on
the planet. Water on the planet's surface makes the existence of past
or present life on Mars a little more likely, according to the group.
Derek Sears, director of the Arkansas-Oklahoma Center for Space and
Planetary Sciences, and his colleagues graduate student Shauntae Moore
and technician Mikhail Kareev reported their initial findings at the
fall 2003 meeting of the Division of Planetary Sciences of the AAS.
The researchers have brought on-line a large planetary environmental
chamber in which temperature, pressure, atmosphere, sunlight and soil
conditions can be reproduced. Sears and his colleagues use the chamber
to investigate the persistence of water under a range of physical
environments and to study its evaporation.
For their first experiments, reported at the DPS meeting, the group
chose to measure one of the most important properties of water on a
planetary surface, the rate at which it evaporates.
"Physicists have long argued that Mars is currently a sterile desert,
completely unsuited to life," Sears said. "This conclusion is based on
their belief that water would evaporate very quickly, as soon as it
appeared on the surface."
The University of Arkansas group examined the effect of Mars'
atmospheric conditions -- temperature and wind -- on the evaporation
rate. The movement of the atmosphere close to the surface is a crucial
factor in the survival of water on Mars. Water evaporates more slowly
when evaporated molecules build up over the water's surface, but wind
sweeps away evaporated molecules, allowing more water molecules to
escape the surface and increasing evaporation rates.
"These findings suggest that even under worst case scenarios, where
wind is maximizing evaporation, evaporation rates on Mars are quite
low," Sears said. This implies that surface water could indeed exist,
or have existed recently, under the given conditions on Mars.
In addition to the evaporation experiments, the group examines the
ways in which water-ice behaves when frozen at depth and how it reacts
when covered with layers of frost or dust. They also explore how ice
behaves when exposed on the surface, and whether it can exist in a
transient liquid phase that could harbor life.
The subtle balance between the input of heat from the Sun and
subsurface sources and the strength of the surface atmospheric motions
determines the fate of the water; whether it remains as ice, becomes
liquid, and if so how long it remains as a liquid, or how quickly it
evaporates.
"The environmental chamber will enable us to gain new insights into
the behavior of water on Mars and reduce much of the speculation on
this topic," said Barney Farmer, principal investigator for the
atmospheric water vapor mapping experiment during the Viking missions
and a member of the Arkansas research group.


EDITORS NOTE: Dr. Sears will be at the Doubletree Monterey during the
meeting. The number there is (831) 649-4511.
==============================*=======


Here is an abstract to this month's LPSC discussing this:


STABILITY OF WATER AND GULLY FORMATION ON MARS.
Derek Sears1,2, Larry Roe1,3, and Shauntae Moore1,2.
1W. M. Keck Laboratory for Space Simulation, Arkansas Center for Space and Planetary Sciences, University of Arkansas, Fayetteville, AR 72701, 2Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701,
3Department of Mechanical Engineering, University of Arkansas, Fayetteville, AR 72701.
Lunar and Planetary Science XXXVI (2005) 1496.pdf
"We measured evaporation rates at 7 mb under
conditions much closer to martian than previous
work and eight determinations yielded a value of
1.04 ± 0.14 mm/h [7]."
http://www.lpi.usra.edu/meetings/lpsc2005/pdf/1496.pdf


Bob Clark

[Alpha_Tauri]

The paper seems to be talking about pure water (correct me if I'm wrong), but what about brine?

Read it in more detail. Brines are also discussed.

[Alpha_Tauri]

Levin is aware that liquid water on the surface would eventually evaporate. His point is that microorganisms could survive on liquid water available for only minutes in a day, and then go into a long suspended date during the period when conditions are too cold.

I have no problem with the fact that ephemeral liquid water can theoretically exist on Mars for extremely brief periods. That was also the conclusion of the paper I cited. Levin jumps one stage further and claims that not only is water possible, but that it can be proven to exist from the Pancam data. Let's stick to my original assertion that the paper is seriously flawed without bringing in other papers.

In particular, I am referring to this paper:

http://mars.spherix.com/5555-14.PDF

Specifically it is using nonsensical data to 'prove' that we are seeing mud in some of the images from the Meridiani landing site.

His sole argument is that the Absorption coefficient of water increases with increasing wavelength over the range of the Pancams.

"Figure 8b taken at 753nm shows darker darks than Figure 8a taken at 535nm............but the increasing darkness indicating water, is obvious:"

The source of the data is from raw images taken from the NASA site. Not only is this uncorrected for exposure, but the assertion is made that because it gets darker with increasing wavelength, it is 'obviously water'.

As has been pointed out elsewhere, there are a number of substances commonly found on Mars that exhibit a similar spectrum over this range.

That is by no means the only flaw in the paper, but let's concentrate on that one for now.

"Levin is aware that liquid water on the surface would eventually evaporate. "

I'm not sure exactly what Levin is aware of, but Bob, how can you honestly defend such a flawed paper? I'm sure that the reputable researchers that you cited would not thank you for the association.

[Alpha_Tauri]

Now Opportunity HAS detected surface frost at least on the landers.

Next question?
Bob Clark

I agree that surface frost has been detected on the solar panel of Opportunity, and there is a chance that it could have been present on the surface. However, how do you get from short lived frost deposits which subliminate during the earliest part of a mid-winter's Sol, to mud ?

That frost would have been detectable using the Mini TES instrument if it were activated during this period, however that instrument is not normally used until later in the Sol.

Free water in the form of mud or brine would be detectable using the Mini TES. If this had been detected, NASA would have been the first to announce it, just as they announced the frost on the panels.

[RGClark]

Levin is aware that liquid water on the surface would eventually evaporate. His point is that microorganisms could survive on liquid water available for only minutes in a day, and then go into a long suspended date during the period when conditions are too cold.

I have no problem with the fact that ephemeral liquid water can theoretically exist on Mars for extremely brief periods. That was also the conclusion of the paper I cited. Levin jumps one stage further and claims that not only is water possible, but that it can be proven to exist from the Pancam data. Let's stick to my original assertion that the paper is seriously flawed without bringing in other papers.

In particular, I am referring to this paper:

http://mars.spherix.com/5555-14.PDF

Specifically it is using nonsensical data to 'prove' that we are seeing mud in some of the images from the Meridiani landing site.

His sole argument is that the Absorption coefficient of water increases with increasing wavelength over the range of the Pancams.

"Figure 8b taken at 753nm shows darker darks than Figure 8a taken at 535nm............but the increasing darkness indicating water, is obvious:"

The source of the data is from raw images taken from the NASA site. Not only is this uncorrected for exposure, but the assertion is made that because it gets darker with increasing wavelength, it is 'obviously water'.

As has been pointed out elsewhere, there are a number of substances commonly found on Mars that exhibit a similar spectrum over this range.

That is by no means the only flaw in the paper, but let's concentrate on that one for now.

"Levin is aware that liquid water on the surface would eventually evaporate. "

I'm not sure exactly what Levin is aware of, but Bob, how can you honestly defend such a flawed paper? I'm sure that the reputable researchers that you cited would not thank you for the association.

You were referring to more than just that paper. You were making the blanket contention that liquid water wouldn't exist on Mars. Actual experiments wouldn't support that claim.
I can tell you that in the papers themselves where he discusses his labeled release experiment he specifially mentions that liquid water would be temporary but he says that is all microorganisms would need to survive.
The reputable researchers I cited would have no problem with Levin's contention that liquid water could exist for short times on Mars, since that is what their research shows.
I did a search within the Levin article you mentioned:

Interpretation of new results from Mars with respect to life.
http://mars.spherix.com/5555-14.PDF

and no where does he use the word *prove* in regards to liquid water at the MER landing sites. The only time he uses the word *prove* is in relation to his contention that his experiment on the Viking mission prove life on Mars.
I believe what Levin is saying in regard to liquid water using the PANCAM images is that they are *consistent with* liquid water.


Bob Clark

[Alpha_Tauri]

I believe what Levin is saying in regard to liquid water using the PANCAM images is that they are *consistent with* liquid water.


Bob Clark

...and on the basis on the information presented, he can't even say that in any sort of meaningful way. The data has not even been corrected for exposure for the various filters.

Even looking at the spectrum over this narrow range, it is also consistent with olivine and/or hydrated salts.

"and no where does he use the word *prove* in regards to liquid water at the MER landing sites."

Perhaps not, but to say, "but the increasing darkness indicating water, is obvious" is getting pretty close. It goes much further than saying that it's merely consistent with liquid water.


What I'm saying is that the paper rings alarm bells all over the place. If it is consistent with anything, it is consistent with very little knowledge of scientific principles. And a little knowledge is a dangerous thing.

[JonClarke]

It is quite understandable that Levin, who surely is pushing 80, wants to see his experiment vindicated before he shuffles off this mortal coil. However the facts have not changed since Viking. A both sites, multiple tests of the top 10 cm saw that:

The pyrolic release results gave results consistent with oxidative chemistry and not biology

The gas exchange experiment gave results consistent with the same chemistry and not biology

The labeled release experiment gave results consistent with both biology or the same chemistry as the others.

The gas chromatograph-mass spectrometer showed that simple organics were absent at ppm levels and above, complex organics at ppb levels and above. This is consistent with oxidative chemistry.

Furthermore, the camera showed no sign of motile macroscopic organisms.

The most likely conclusion has to be that the soil at both sites contains no biology but a strong oxidant that actively destroys incoming organic matter including meteorites. Because this material shows global distribution it is likely the same results would be repeated globally.

If there is life on Mars it is most probable in either the subsurface or at rare oases. Nothing has happened since Viking to change this.

Jon

[Alpha_Tauri]

It is quite understandable that Levin, who surely is pushing 80, wants to see his experiment vindicated before he shuffles off this mortal coil.

I have nothing against Levin himself, but I will argue against pseudoscience masquerading as science regardless of who wrote it. The problem is that there are too many people quoting this paper, at least on forums such as this (although virtually nobody in the mainstream takes him seriously) and too few people have had the guts to debunk this nonsense. It needs to be debunked once and for all.

If there is life on Mars it is most probable in either the subsurface or at rare oases. Nothing has happened since Viking to change this.

I agree. If there is life to be found, perhaps some underground refuge that is still heated by vestigial geothermal energy would be the place to look.

[JonClarke]

I think it is fair to say that LR was a great experiment and the original conclusions by Levin were that the results were consistent with life but also other explanations well justified. The problem has been he has become more strident with time and completely ignored the other experiments. In the absence of new data Levin can only publish in non-mainstream journals and on the web. It is quite sad really.

I think we can and should give an old man with considerable achievements some slack. But other people need to be constantly reminded that overal Viking did not discover life and that this conclusion is entirely reasonable. The results of the PR, GX and GCMS experiments must constantly be brought back into people's attention. It is simply not the case that NASA and the astrobiology community has ignored or suppressed Levin, despite what people we both know maintain :wink:

Cheers

Jon

[RGClark]

It is quite understandable that Levin, who surely is pushing 80, wants to see his experiment vindicated before he shuffles off this mortal coil.

I have nothing against Levin himself, but I will argue against pseudoscience masquerading as science regardless of who wrote it. The problem is that there are too many people quoting this paper, at least on forums such as this (although virtually nobody in the mainstream takes him seriously) and too few people have had the guts to debunk this nonsense. It needs to be debunked once and for all.

If there is life on Mars it is most probable in either the subsurface or at rare oases. Nothing has happened since Viking to change this.

I agree. If there is life to be found, perhaps some underground refuge that is still heated by vestigial geothermal energy would be the place to look.

ALOT has changed since Viking! We know there is several percent water/ice within centimeters of the Viking landing sites. We also have experimental evidence that liquid water could persist for minutes to hours on the surface of Mars.
We now know that the Viking GCMS could not have detected the organics contained in millions of microbes per gram. It is simply unjustified to claim there are NO organics on Mars based on this instrument.
There are plans underway and instruments already designed for more sensitive organic detection on Mars.
I don't know why you say no one debunks Levin. Most mainstream Mars scientists disagree with his stance there is active life on Mars and say so when asked.


Bob Clark

[RGClark]

I think it is fair to say that LR was a great experiment and the original conclusions by Levin were that the results were consistent with life but also other explanations well justified. The problem has been he has become more strident with time and completely ignored the other experiments. In the absence of new data Levin can only publish in non-mainstream journals and on the web. It is quite sad really.

I think we can and should give an old man with considerable achievements some slack. But other people need to be constantly reminded that overal Viking did not discover life and that this conclusion is entirely reasonable. The results of the PR, GX and GCMS experiments must constantly be brought back into people's attention. It is simply not the case that NASA and the astrobiology community has ignored or suppressed Levin, despite what people we both know maintain :wink:

Cheers

Jon

There is really nothing sad about it. A scientist is supposed to give the reasons for his point of view, even if it disagrees with the mainstream view. That's how scientific revolutions occur.
EVERYBODY already knows about the Viking life experiments and their accepted explanations. And EVERBODY already knows that the life explanation is decidely outside the mainstream.
You say people need to be reminded of them I don't agree. They already know them. What people should be reminded about is the NEW information that the instrument that was used to conclude no organics on Mars did not have the sensitivity to make that determination conclusively.
You're a scientist. You know scientists are supposed to give the sensitivity levels of their instruments when quoting their results. If WHENEVER any Mars scientist or science reporter ever mentioned Viking GCMS results they ALWAYS said "the Viking instruments showed no organics on Mars except perhaps the equivalent of 1 million microbes per gram", do you think people would continue to say Viking "proved no life on Mars"?



Bob Clark

[Alpha_Tauri]

Bob,

My post was about the claim that there was mud at the Opportunity landing site in the paper by Levin. I think you will agree that the argument used to justify mud in this paper was flawed.

Most mainstream workers ignore Levin for obvious reasons, such as the above. I was simply pointing out the fantastic nature of the argument used, so that I didn't have to continually rebut the reference of this paper on forums such as this.

ALOT has changed since Viking! We know there is several percent water/ice within centimeters of the Viking landing sites. We also have experimental evidence that liquid water could persist for minutes to hours on the surface of Mars.

Do we? The only information that I have seen is from the Hend instrument, and this is incapable of differentiating between water, or hydrogen in hydrated minerals and free water/ ice.

Please tell me more.

A lot has indeed changed since Viking. We also have the experimental evidence that superoxide (O3.) is produced by the action of UV radiation on Martian regolith. This confirms the finding from Viking that there are strong oxidants present on the surface of Mars.

[JonClarke]

Bob

It is one thing to defend your ideas when they are against the mainstream because you think they are right it is another thing to defend them when they have been proved wrong and to keep doing so, ignoring contrary evidence. This is just pride not science. You see it all the time. Sam Carey, Tom Gold, Fed Hoyle etc.

The scientific community generally ignore Levin for good reason. There is no new relevant data, the evidence against widespread life on the surface still stands, and Levin has nothing new to say. More serious is the fact that his supporters ignore all the other data and focus on one experiment, the LR, the results of which Levin AT THE TIME acknowledged was as consistent with chemsitry as biology. The lack of complex molecules at ppb level, the experiments that produce superoxides in mars analogue materials under Mas surface conditions, the absence of surface life inthe most mars like Martian environments on earth like parts of the Atacama, these are facts that Levin's supporters ignore.

Very little of substance has changed since Viking with respect to Mars. All the recent discoveries - subsurface ice, the stability of water calculations, lake and river deposits were all known or suspected before Viking, some, like ground ice, were suspected before Mariner - indeed Arthur Wallace postulated this in the 19th century. We have more evidence for these, thanks to recent missions, that is all. ALH84001 does not contribute anything to the debate because it is inconclusive and came from beneath the surface anyway. The methane may point to subsurface life, but Viking was about surface life, so the recent methane discoveries are irrelevant. Not to mention there are a host on non-biological explanations.

This is why scientists generally don't take Levin seriously. However on the popular fringe it is He who gets the publicity, it is his experiment that is described as part of Viking. The general public who is interested in Mars often isn't even aware that the results were ambigious and the other experiments were negative. This is especially the case for the GCMS, the results of which are fatal for any widespread occurrence of life. Indeed, the evevation of Levin to the patron saint of life on Mars by woo woos and boarderline woo woos like the group against mars sample return is actually harmful to his case, making it easier for other scientists to dismiss what limit merits his arguments might still have.

Saying that Viking found life on mars and that Levin was right is flogging a very dead horse. There may be life on Mars, but the probability that Viking did not find it is very high. We need more data, data on the superoxide chemsitry, data from the subsurface, below the 10 cm or so that Viking was able to dig. It would have been nice if Beagle, Mars 96, and MPL had been a success, they would have shed some data. As it is we will have to wait until Phoenix, MSL and ExoMars.

Jim, with respect to water, there were two instruments that detect hydrogen on MO - HEND and the GRS neutron detector. Both map similar values. While it cannot differentiate between free and bound water, once you start getting water contents above 12% you have to have free ice, as no hydrated minerals have that much water. North and South of 60 degree latitudes both instruments point to water contents in the top metre of above 50%

Best

Jon.

[Alpha_Tauri]

Jim, with respect to water, there were two instruments that detect hydrogen on MO - HEND and the GRS neutron detector. Both map similar values. While it cannot differentiate between free and bound water, once you start getting water contents above 12% you have to have free ice, as no hydrated minerals have that much water. North and South of 60 degree latitudes both instruments point to water contents in the top metre of above 50%

Best

Jon.

Jon,

The last time I checked, Epsomite contains 51% water by weight, and gypsum has 21% water by weight . Both the the GRS and the Russian instrument use epithermal neutrons to detect hydrogen. In the case of the GRS, the gamma rays are a secondary effect caused by neutrons.

I have no argument with the fact that there is surface ice in the near Polar regions, however in the Equatorial regions, it is more likely that the hydrogen comes from hydrated minerals, where such minerals have been positively confirmed by both Spirit and Opportunity.

I also tend to have more credence for surface observation than remote observation in this case. Remote observation has not always been historically reliable, and other explanations can emerge.

Regards,

Jim

[RGClark]

Bob

It is one thing to defend your ideas when they are against the mainstream because you think they are right it is another thing to defend them when they have been proved wrong and to keep doing so, ignoring contrary evidence. This is just pride not science. You see it all the time. Sam Carey, Tom Gold, Fred Hoyle etc.

We're not going to agree on this until another organic detector is sent to Mars that really does have the sensitivity people *believe* the Viking GCMS had.
This is a real sore point for me. And most people don't get (or agree with) how important it is. Because of this, I wrote this little hypothetical scenario:

Scene: Professor R. G. Persnickety is being interviewed about the Viking life results. Dr. Persnickety is well-known for his fastidious attention to detail.

Persnickety: We know that there is no life on Mars because of the Viking life results.

Reporter 1: I thought some of those Viking life experiments gave positive results or at least inconclusive ones.

Persnickety: Yes, some did give responses which according to the prelaunch criteria were considered to be positive. However, the reason we believe these were due to chemistry and not life is because the Viking GCMS didn't get a positive response.

Reporter 2: GCMS? Could you explain what this is?

Persnickety: Yes, it is an instrument that was shown on Earth to be sensitive to the detection of organic compounds. Organic compounds compose all life as we know it. The GCMS didn't detect any organics within its sensitivity level.

Reporter 1: Its sensitivity level?

Persnickety: Yes, of course any instrument has to be calibrated before it is used. Experiments showed it could detect the organics contained in 30 million cells per gram.

Reporter 2: 30 million cells! That sounds like alot. It must be very good!

Reporter 1: Huh?

Persnickety: Yes, actually, as far as sensitivity level is concerned you want this number to be as small as possible. But this really is very good. You see microbes are mostly just water and because microbes are so tiny the organics they contain might be only in the femtograms range, which is quadrillionths of a gram. 30 million cells really is a small amount in weight.

Reporter 1: About that 30 million number, am I understanding you correctly Professor that if a Martian sample only contained say 1 million cells in a gram, the GCMS wouldn't have detected them?

Persnickety: Er, well, yes ....

Reporter 1: That doesn't seem very sensitive to me.

Persnickety: No, that actually is very sensitive because typical fertile Earth soils might contain billions to 10's of billions of cells per gram.

Reporter 1: Fertile Professor?

Persnickety: Yes, the, uh, kinds of soils you might have in your backyard or in arable land.

Reporter 1: Wouldn't a better comparison be to soils that we know have low levels of microbes? Are there cases on Earth with soils with less than a million cells per gram?

Persnickety: Er, yes, there have been some recent samples taken from Antarctica and from Siberia with active life that had the organic content of a few million cells per gram.

Reporter 1: So if the Viking GCMS was used on these samples it would say there is no life there eventhough they did contain active life?

Persnickety: Um, yes ...

Reporter 1: Professor, it seems to me that it's not really justified to say there is no life on Mars if the GCMS instrument would give a false negative reading on known samples on Earth.

Persnickety: Hmmm. To be completely precise, it would be more accurate to say the instruments detected no definitive life within their sensitivity levels, but the possibility of life at this point can not be ruled out.

Reporters 1,2: Thank you very much for your time Professor Persnickety.

Persnickety: Thank You.

[algorithms]

Simply put...Gil Levin did not find life on Mars. That doesn't mean there isn't any life on Mars. It only means that Mr. Levin's labeled release experiment didn't find any.

Of course, we know a lot more today than we did in 1976. But everything we've learned tells us not to expect to find microbial life at surface of Mars, except, perhaps in rare, well-protected micro-environments. The chemistry at the surface is essentially self-sterilizing. The more likely scenario is that we'll find microbial life beneath the surface, if its there at all.

The only folks who take Levin seriously today are the cydonuts who believe that almost every rock found in Pathfinder and Rover images is some kind of creature, piece of hardware or ancient stone artifact.

Levin may be encouraged by what the Rover missions are telling us about the prospects for extant or extinct microbial life on Mars. But he shouldn't delude himself into thinking that he'll get credit for the discovery, if it ever occurs.

[ToSeek]

Simply put...Gil Levin did not find life on Mars. That doesn't mean there isn't any life on Mars. It only means that Mr. Levin's labeled release experiment didn't find any.

That's a rather high-handed statement considering that according to the pre-established criteria it did detect signs of life.

The only folks who take Levin seriously today are the cydonuts who believe that almost every rock found in Pathfinder and Rover images is some kind of creature, piece of hardware or ancient stone artifact.

Ad hominem. Not the sort of claim that is welcome on this board. Argue the facts, don't smear those you disagree with.

[RGClark]

Simply put...Gil Levin did not find life on Mars.

Simply put the issue isn't decided yet.
Most scientists agree on the non-life interpretation, but that doesn't mean they arrived at that conclusion in a logical fashion.


Bob Clark

[algorithms]

RGClark: "Simply put the issue isn't decided yet. Most scientists agree on the non-life interpretation, but that doesn't mean they arrived at that conclusion in a logical fashion."

The issue was decided over twenty five years ago. There are a small minority of folks who think otherwise, who, no matter how hard they try, have failed to convince the scientific community of the veracity of their arguements. To suggest that the vast majority of planetary scientists are "illogical" is "not the sort of claim that is welcome on this board."