Author Topic: Has Curiosity detected methane on Mars?  (Read 31253 times)

Offline Blackstar

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Has Curiosity detected methane on Mars?
« on: 10/23/2012 08:58 PM »
http://www.space.com/18188-mars-methane-curiosity-rover-clues.html


Mars Methane Mystery: Curiosity Rover May Find New Clues

by Leonard David, SPACE.com’s Space Insider Columnist

"There’s growing buzz about data gleaned by NASA’s Mars rover Curiosity, specifically over the issue of methane detection on the Red Planet.

On one hand, methane can be geological in origin. But then there’s the prospect that the gas is biotic, or caused by living organisms — meaning it could be the gaseous residue of long-extinct microbes or even the output of Martian organisms alive and well today."

Offline Robert Thompson

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Re: Has Curiosity detected methane on Mars?
« Reply #1 on: 10/24/2012 02:42 AM »
Your link seems to be patient zero, and the mutation now has that methane has been found.

http://www.belljarnews.com/2012/10/23/nasas-curiosity-discovers-methane-on-mars/

I predict we will have arsenic-based life that use cold fusion and communicate via superlight neutrinos inside 24 hours.  :)
« Last Edit: 10/24/2012 02:52 AM by Hernalt »

Online scienceguy

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Re: Has Curiosity detected methane on Mars?
« Reply #2 on: 10/24/2012 03:13 AM »
Your link seems to be patient zero, and the mutation now has that methane has been found.

http://www.belljarnews.com/2012/10/23/nasas-curiosity-discovers-methane-on-mars/

I predict we will have arsenic-based life that use cold fusion and communicate via superlight neutrinos inside 24 hours.  :)

lol
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Offline kevin-rf

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Re: Has Curiosity detected methane on Mars?
« Reply #3 on: 10/24/2012 10:48 AM »
Well it is now on NSF so it must be true!
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Offline Blackstar

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Re: Has Curiosity detected methane on Mars?
« Reply #4 on: 10/24/2012 03:03 PM »
I had heard rumors about this methane detection last month. Apparently they got a sign as soon as they took a sniff of the air. But unlike in the movies, in real science when you get interesting data you don't immediately call a press conference. And of course NASA has made some fumbles in the past--ALH84001 was a bust, and the arsenic-based life was a bust too.

Offline robertross

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Re: Has Curiosity detected methane on Mars?
« Reply #5 on: 10/24/2012 03:27 PM »
I had heard rumors about this methane detection last month. Apparently they got a sign as soon as they took a sniff of the air. But unlike in the movies, in real science when you get interesting data you don't immediately call a press conference. And of course NASA has made some fumbles in the past--ALH84001 was a bust, and the arsenic-based life was a bust too.


That would be another great find!

I hope there's enough to choke on  (j/k)
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Online meekGee

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Re: Has Curiosity detected methane on Mars?
« Reply #6 on: 10/24/2012 05:08 PM »
Any new data on the Methane would be great, one way or the other.

Unfortunately, all this story does is recap the background for Methane on Mars, and adds that there's currently Buzz around measurements from Curiosity.

So the Methane is exciting, the story is an empty teaser.... 

I didn't know that they can take isotopic ratio measurements though.  So I guess not completely empty.
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Offline spacermase

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Re: Has Curiosity detected methane on Mars?
« Reply #7 on: 10/24/2012 05:24 PM »
Any new data on the Methane would be great, one way or the other.

Unfortunately, all this story does is recap the background for Methane on Mars, and adds that there's currently Buzz around measurements from Curiosity.

So the Methane is exciting, the story is an empty teaser.... 

I didn't know that they can take isotopic ratio measurements though.  So I guess not completely empty.

IIRC, the Tunable Laser Spectrometer ought to be able to do isotopic analysis, though the methane may not be in high enough quantity to get a good reading.

Offline fthurber

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Re: Has Curiosity detected methane on Mars?
« Reply #8 on: 10/24/2012 05:30 PM »

I didn't know that they can take isotopic ratio measurements though.  So I guess not completely empty.

These measurements, done by the TLS (Tunable Laser Spectrometer), will be key to determining the origin of the methane.  TLS will be used to measure carbon isotopes in any methane SAM finds (as long as they can get enough); as you know the carbon 12/13 ratio is indicative of possible biological genesis since life (at least life on Earth) will preferentially use C12 as opposed to C13.

TLS can also measure carbon and oxygen isotopes in CO2 and water.

The team has been cagey (but not as cagey as Bill Belichick at a press conference!) about the results so far.  They only gave results the first week when they detected methane but it was from air trapped in the SAM/TLS from Florida, not Martian air. So they flushed the system and (at last count) made 3 more measurements.  I think that they have to concentrate the methane also which may take a lot of time.   I suspect that they found methane and are being very careful with these results.  The results should be very, very interesting, but I don't expect them until December.
 
« Last Edit: 10/26/2012 12:48 PM by fthurber »

Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #9 on: 10/25/2012 08:19 PM »
Quote from: Thurber
They only gave results the first week when they detected methane but it was from air trapped in the SAM/TLS from Florida, not Martian air. So they flushed the system and (at last count) made 3 more measurements.

Speaking from the back seat:

I trust it was sterile methane.  It was not seen fit to flush that system and maybe fill it with helium or some other inert gas before leaving Earth?
« Last Edit: 10/25/2012 08:20 PM by JohnFornaro »
Sometimes I just flat out don't get it.

Offline Quindar Beep

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Re: Has Curiosity detected methane on Mars?
« Reply #10 on: 10/26/2012 02:53 PM »
I predict we will have arsenic-based life that use cold fusion and communicate via superlight neutrinos inside 24 hours.  :)

And that it's coming from the mouth of the Face on Mars.

IT'S ALL CONNECTED, PEOPLE! **puts on tinfoil hat**

Offline Nomadd

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Re: Has Curiosity detected methane on Mars?
« Reply #11 on: 10/26/2012 02:57 PM »
 It wouldn't be the face. It would be from the yet undiscovered other end.

Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #12 on: 10/26/2012 02:59 PM »
...I predict we will have arsenic-based life that use cold fusion and communicate via superlight neutrinos inside 24 hours.

If that were true, you'd already know this to be the case.

Wait a minute.

You already do.
Sometimes I just flat out don't get it.

Offline Garrett

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Re: Has Curiosity detected methane on Mars?
« Reply #13 on: 10/26/2012 03:12 PM »

I trust it was sterile methane.  It was not seen fit to flush that system and maybe fill it with helium or some other inert gas before leaving Earth?

What do mean by "sterile methane"? CH4 is CH4
Also, even if you flush a system with an inert gas, trace molecules of CH4, etc. can rest because of adsorption, absorption and migration onto/into the material surfaces. In a vacuum environment, they then outgas and can be observed with a sensitive detector.
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Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #14 on: 10/26/2012 04:29 PM »

I trust it was sterile methane.  It was not seen fit to flush that system and maybe fill it with helium or some other inert gas before leaving Earth?

What do mean by "sterile methane"? CH4 is CH4
Also, even if you flush a system with an inert gas, trace molecules of CH4, etc. can rest because of adsorption, absorption and migration onto/into the material surfaces. In a vacuum environment, they then outgas and can be observed with a sensitive detector.

I don't really have a handle on the correct language. 

But methane is not methane.  There is floridian methane, and martian methane by Thurber's telling.  And if there are trace molecules from our highly organically enriched floridian methane observable to a sensitive detector, then to me, at least, the sterility of that there methane needs to be questioned.

In other words, we may have already detected signs of life, and everybody's on board with that?
Sometimes I just flat out don't get it.

Offline Hungry4info3

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Re: Has Curiosity detected methane on Mars?
« Reply #15 on: 10/26/2012 04:58 PM »
I don't know much what the terminology is either, how they distinguish Earth methane from Mars methane, other than possibly by repeatedly flushing the system and seeing if residual CH4 remains after the other Earth-only gases are gone. Maybe there's different isotopes of C to look for. I don't know, I don't really know much about chemistry.

But what I do know is that CH4 detection is not equivalent to "signs of life" because CH4 can be produced through other, purely abiotic means.

Offline go4mars

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Re: Has Curiosity detected methane on Mars?
« Reply #16 on: 10/26/2012 05:05 PM »
Isotope ratios.
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Offline Hungry4info3

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Re: Has Curiosity detected methane on Mars?
« Reply #17 on: 10/26/2012 05:06 PM »
Isotope ratios.
Can you be more specific? Which isotope is favoured by biological processes?

Offline kevin-rf

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Re: Has Curiosity detected methane on Mars?
« Reply #18 on: 10/26/2012 05:12 PM »
http://en.wikipedia.org/wiki/Carbon-13
Quote
Due to differential uptake in plants as well as marine carbonates of 13C, it is possible to use these isotopic signature in earth science. In aqueous geochemistry, by analyzing the δ13C value of surface and ground waters the source of the water can be identified. This is due to the fact that atmospheric, carbonate, and plant derived δ13C values all differ with respect to Pee Dee Belemnite (PDB) standard.

And don't forget:
http://en.wikipedia.org/wiki/Carbon-12
http://en.wikipedia.org/wiki/Carbon-14 (Carbon Dating Isotope)


Edit:

http://en.wikipedia.org/wiki/Isotopes_of_carbon
Quote
Stable carbon isotopes in carbon dioxide are utilized differentially by plants during photosynthesis. Grasses in temperate environments (barley, rice, wheat, rye and oats, plus sunflower, potato, tomatoes, peanuts, cotton, sugar beet, and most trees and their nuts/fruits, roses and Kentucky bluegrass) follow a C3 photosynthetic pathway that will yield δ13C values averaging about −26.5‰. Grasses in hot arid environments (maize in particular, but also millet, sorghum, sugar cane and crabgrass) follow a C4 photosynthetic pathway that produces δ13C values averaging about −12.5‰.

All this requires detailed knowledge of the C12/C13 ratio's on mars. Do we have that data point yet? Could that data have already been returned by either MER's Alpha Particle X-Ray Spectrometer or the Mössbauer Spectrometer?
« Last Edit: 10/26/2012 05:19 PM by kevin-rf »
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Offline Hungry4info3

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Re: Has Curiosity detected methane on Mars?
« Reply #19 on: 10/26/2012 05:21 PM »
Thanks.
I was under the impression that this would be a bit more ambiguous for Mars since we don't have a baseline of geologically produced CH4 to compare any detected biologically produced CH4 to.

Is there really a specific relative 13C abundance above which we can safely say "this has to be produced by life"?

Edit: I see your edit now.
« Last Edit: 10/26/2012 05:23 PM by Hungry4info3 »

Offline Blackstar

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Re: Has Curiosity detected methane on Mars?
« Reply #20 on: 10/26/2012 05:36 PM »

I trust it was sterile methane.  It was not seen fit to flush that system and maybe fill it with helium or some other inert gas before leaving Earth?

What do mean by "sterile methane"? CH4 is CH4
Also, even if you flush a system with an inert gas, trace molecules of CH4, etc. can rest because of adsorption, absorption and migration onto/into the material surfaces. In a vacuum environment, they then outgas and can be observed with a sensitive detector.

John has a default assumption that most of the people who work in the space field are incompetent.

Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #21 on: 10/26/2012 05:47 PM »
John has a default assumption that most of the people who work in the space field are incompetent.

No, John does not. 

Tell us why the yet to be purged methane in the system is known not to be contaminated by Earthly bacteria in trace amounts.

Tell us why flushing that system and filling it with an inert gas while on Earth is an "incompetent" suggestion, and not at all necessary when sterilizing the rover here on Earth.

I will admit that the phrasing of my question could have been less "loaded", and will work on that wording in the future. 
« Last Edit: 10/27/2012 01:38 PM by JohnFornaro »
Sometimes I just flat out don't get it.

Offline fthurber

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Re: Has Curiosity detected methane on Mars?
« Reply #22 on: 10/26/2012 08:00 PM »
Thanks.
I was under the impression that this would be a bit more ambiguous for Mars since we don't have a baseline of geologically produced CH4 to compare any detected biologically produced CH4 to.

Is there really a specific relative 13C abundance above which we can safely say "this has to be produced by life"?

Edit: I see your edit now.

Ambiguous yes, but intriguing. 

I think that a guess on baseline abiotic methane C13/C12 ratios could be made from C13/C12 ratios in, say, asteroids, comets, etc.  Did the Phoenix lander measure C13/C12 ratios in CO2?  That might help.

If C12 is enhanced compared to C13 above these levels then this hints at a biological origin, but we do not know if potential life on Mars is as selective as life on Earth as far as C12 uptake.  Anything more would seem very speculative.



Offline fthurber

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Re: Has Curiosity detected methane on Mars?
« Reply #23 on: 10/26/2012 08:22 PM »
It would appear that SAM's Quadrupole Mass Spectrometer is taking a measurement of the Martian atmosphere on Sol 78.  Is it looking for other gases?

Offline Quindar Beep

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Re: Has Curiosity detected methane on Mars?
« Reply #24 on: 10/26/2012 08:29 PM »
If C12 is enhanced compared to C13 above these levels then this hints at a biological origin, but we do not know if potential life on Mars is as selective as life on Earth as far as C12 uptake.  Anything more would seem very speculative.


Note incidentally that when talking methane it's 13C:14C that we're interested in. 12C is the more common marker, but it's used in different contexts.

Putting that aside as a typo, I think you've got it backwards. If 13C is enhanced it would be a strong sign of life, as there's no known abiological process that can sort between different isotopes of carbon.

Rather, if the ratio looks normal it would not rule out Martian life because Martian life may not be as selective as ours.

(On the other hand, even very simple life forms on Earth are so it would be somewhat suggestive that Mars is dead.)
« Last Edit: 10/26/2012 08:30 PM by Quindar Beep »

Offline Star One

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Re: Has Curiosity detected methane on Mars?
« Reply #25 on: 10/27/2012 12:40 PM »
Hopefully not too off topic but when MAVEN arrives at Mars is its studies of the atmosphere specifically designed to tie in with Curiosity's on the surface or is it more doing its own thing? (Probably not explained that very well.)

Online meekGee

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Re: Has Curiosity detected methane on Mars?
« Reply #26 on: 10/27/2012 06:15 PM »
If C12 is enhanced compared to C13 above these levels then this hints at a biological origin, but we do not know if potential life on Mars is as selective as life on Earth as far as C12 uptake.  Anything more would seem very speculative.


Note incidentally that when talking methane it's 13C:14C that we're interested in. 12C is the more common marker, but it's used in different contexts.

Putting that aside as a typo, I think you've got it backwards. If 13C is enhanced it would be a strong sign of life, as there's no known abiological process that can sort between different isotopes of carbon.

Rather, if the ratio looks normal it would not rule out Martian life because Martian life may not be as selective as ours.

(On the other hand, even very simple life forms on Earth are so it would be somewhat suggestive that Mars is dead.)


Do you know btw how life sorts out isotopes?   I mean in chemistry isotopes are not distinguishable.  There's clearly a density difference, but this only shows up if you ave a vertical buoyancy-based separator - shouldn't make a difference within the context of a chemical reaction.

Just curious about the mechanism here.
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Offline fthurber

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Re: Has Curiosity detected methane on Mars?
« Reply #27 on: 10/27/2012 08:14 PM »
If C12 is enhanced compared to C13 above these levels then this hints at a biological origin, but we do not know if potential life on Mars is as selective as life on Earth as far as C12 uptake.  Anything more would seem very speculative.


Note incidentally that when talking methane it's 13C:14C that we're interested in. 12C is the more common marker, but it's used in different contexts.

Putting that aside as a typo, I think you've got it backwards. If 13C is enhanced it would be a strong sign of life, as there's no known abiological process that can sort between different isotopes of carbon.

Rather, if the ratio looks normal it would not rule out Martian life because Martian life may not be as selective as ours.

(On the other hand, even very simple life forms on Earth are so it would be somewhat suggestive that Mars is dead.)


Are you sure about this Quindar?  I seem to remember that TLS is specifically designed to measure carbon-12 to carbon-13 isotopic ratios in methane not carbon-14.  As far as I know terrestrial plant life will preferentially use C12 versus C13.heck

Check out this official SAM document by Mahaffy (http://msl-scicorner.jpl.nasa.gov/Instruments/SAM/); TLS is geared toward C13/C12 measurements (and oxygen isotopes) in methane and other organics but not toward C14.   C14 is used on Earth for carbon dating but it is not very relevant on Mars...
on 14


« Last Edit: 10/28/2012 12:10 AM by fthurber »

Offline Quindar Beep

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Re: Has Curiosity detected methane on Mars?
« Reply #28 on: 10/27/2012 11:58 PM »
Are you sure about this Quindar?  I seem to remember that TLS is specifically designed to measure carbon-12 to carbon-13 isotopic ratios in methane not carbon-14.  As far as I know terrestrial plant life will preferentially use C12 versus C13.

You're quite right, my mistake. The number we're after is called δ13C, which I had in my head as being the ratio of 13 to 14. But it is 12 to 13 after all:

https://en.wikipedia.org/wiki/%CE%9413C

In particular, the test we're looking at is based on the facts in the section labelled "What affects δ13C?"

Offline Quindar Beep

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Re: Has Curiosity detected methane on Mars?
« Reply #29 on: 10/28/2012 12:16 AM »
Do you know btw how life sorts out isotopes?   I mean in chemistry isotopes are not distinguishable.  There's clearly a density difference, but this only shows up if you ave a vertical buoyancy-based separator - shouldn't make a difference within the context of a chemical reaction.

It's photosynthesis that does it particularly -- animals have skewed carbon isotope ratios solely because they eat plants or eat other animals that have eaten plants. The heavier isotope forms slightly stronger bonds, so plants can get more carbon from CO2 with less energy if the C in the gas molecule is 12C.

I'm given to understand that the most important chemical step in photosynthesis that causes this is the initial carboxylation, when the CO2 is attached to 1,5-bisphosphate carboxylase (https://en.wikipedia.org/wiki/RuBisCO).

The mass difference does come into play as well when you consider that a lot of the movement in plants is caused by osmosis and diffusion. Diffusion was the key to the first important separation technique used to pull apart U-235 and U-238, for example.
« Last Edit: 10/28/2012 12:21 AM by Quindar Beep »

Offline KelvinZero

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Re: Has Curiosity detected methane on Mars?
« Reply #30 on: 10/28/2012 12:18 AM »

Do you know btw how life sorts out isotopes?   I mean in chemistry isotopes are not distinguishable.  There's clearly a density difference, but this only shows up if you ave a vertical buoyancy-based separator - shouldn't make a difference within the context of a chemical reaction.

Just curious about the mechanism here.

(beep entered their answer as I was editing this..)

This is just a guess from some googling, but might be this: "kinetic isotope effect".. apparently heavier isotopes react a bit slower, biasing life towards lighter isotopes.

link on kinetic isotope effect:
http://en.wikipedia.org/wiki/Isotope#Chemical_and_molecular_properties

link saying biochemical reactions favor lighter isotopes:
http://arstechnica.com/science/2012/05/methane-made-from-meteors-may-explain-mars-mystery/
Our solar system has an average ratio of the two common carbon isotopes, but life tends to change that, since biochemical reactions slightly favor the use of lighter isotopes.

I imagine this bias could be exaggerated if you are performing reactions repeatedly and discarding leftovers, selecting for faster reacting carbon.

Offline Robert Thompson

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Re: Has Curiosity detected methane on Mars?
« Reply #31 on: 10/28/2012 01:17 AM »
The heavier isotope forms slightly stronger bonds
Like gravitational potential of a single neutron slightly stronger?

Offline Quindar Beep

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Re: Has Curiosity detected methane on Mars?
« Reply #32 on: 10/28/2012 01:24 AM »
Like gravitational potential of a single neutron slightly stronger?

No, gravity would be beyond tiny at that level. The extra neutron would mean more van der Waals forces, I think. Not a lot, but a lot bigger than gravity, that's for sure.

Offline go4mars

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Re: Has Curiosity detected methane on Mars?
« Reply #33 on: 10/28/2012 01:33 AM »
It's photosynthesis that does it particularly
Just did a bit of searching to see whether ratios were skewed among chemosynthetic communities.  Didn't see enough data points to comment.  Anyone out there familiar with the C12/C13 ratios of chemosynthetic organisms (or shells of things that feed on them)?
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Offline randomly

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Re: Has Curiosity detected methane on Mars?
« Reply #34 on: 10/28/2012 01:34 AM »
I think Van der waals forces are forces between dipoles , permanent or induced. How is an uncharged neutron going to affect that? Does in increase the dipole moment? and how?

Offline Warren Platts

Re: Has Curiosity detected methane on Mars?
« Reply #35 on: 10/28/2012 01:51 AM »
Bottom line: The results are and will remain inconclusive--but ever-so tantalizing....

:o
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Offline Quindar Beep

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Re: Has Curiosity detected methane on Mars?
« Reply #36 on: 10/28/2012 01:59 AM »
I think Van der waals forces are forces between dipoles , permanent or induced. How is an uncharged neutron going to affect that? Does in increase the dipole moment? and how?

If it were just an atom of carbon, none at all. But it's in a methane molecule (edit to add: or carbon dioxide) so it's going to change the molecular geometry a bit if you make the carbon more massive.

Not a lot, mind you, but certainly bigger than the increase in gravity caused by adding an extra neutron.
« Last Edit: 10/28/2012 01:01 AM by Quindar Beep »

Offline Tetrakis

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Re: Has Curiosity detected methane on Mars?
« Reply #37 on: 10/28/2012 03:13 AM »
Hello, I'm a chemist who lurks the forum.

The kinetic isotope effect in biochemistry is most frequently caused by one of two mechanisms: the lowering of the zero-point vibrational state's energy in a chemical intermediate and the increased ability for an atom (practically speaking, lighter elements like hydrogen) to tunnel through a reaction barrier. Lighter elements have a reduced ability to tunnel through finite potentials because of the inverse mass dependence in the Schrodinger equation; this is why electron tunneling is so easy as to find technological applications in electrical engineering, but proton tunneling is just an arcane curiosity of analytical chemistry used to purify deuterium.

To give a quick example of how the bond length in isotopically substituted molecules remain the same but the effective bond strength can change, consider dihydrogen cation. The morse potential for the molecule is defined by the relation between the coulombic potential energy between the two nuclei and the single electron and the kinetic energy of the electron wavefunction across varying internuclear radii, so the energy optimized bond length is not affected by the mass of either nucleon (nucleii are so heavy as to have negligible size on a molecular scale). However, the quantized vibrational energy levels are affected because the vibrational frequency of a harmonic oscillator is determined by it's effective mass; the lowest energy level is stabilized, while the highest energy level corresponding to complete bond dissociation is not. The energy difference between the resting state of the molecule and it's dissociation product is increased, increasing the effective strength of the bond (D0) while not actually affecting the potential energy surface of the system or the maximum well depth of the oscillating molecule(De).



Curiously, while the geometry of a fully energy optimized molecule at equilibrium bond length is not changed the effective bond length can be increased with lower substituted atom mass. The effective radius is altered because internuclear vibrational potentials are not perfectly harmonic, and as the lowest vibrational energy level is destabilized up the morse potential the average position of an isotopically substituted atom away from it's vibrational partner(s) is increased. This means that the effective bond length increases with decreasing mass; as an example, carbon 13 methane would have somewhat shortened C-H bonds because the effective mass of a normal mode in CH4 would be increased; the molecule would be "smaller", even though no change in the potential energy surface had taken place. Someone above said that C13 would give methane a different net dipole, or change it's van der waals forces; that would simply not be the case, due to the Td symmetry of the methane molecule. A single deuteron would, however, because the molecule would no longer have a cubic point group.

Also: Space is cool.  8)
« Last Edit: 10/28/2012 03:31 AM by Tetrakis »

Offline sdsds

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Re: Has Curiosity detected methane on Mars?
« Reply #38 on: 10/28/2012 05:23 AM »
Also: Space is cool.  8)

Excellent post. Thanks for de-lurking!
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Re: Has Curiosity detected methane on Mars?
« Reply #39 on: 10/28/2012 07:34 AM »
Thanks for the explanations - I always wondered about that.

The chain of reasoning so far went as follows:
- Methane was detected
- Methane has a short half-life due to UV
- Methane is therefore produced
- Let's find out if it is biological in origin or not by using isotope ratios.

What is the reference point for the isotope ratio?  CO2?  Carbon in the ground?

I'm asking, since even though CO2 is not necessarily currently produced, some of it might still have a recent origin. Can we learn something from the isotope ratio of Carbon in the atmospheric CO2?
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Offline Quindar Beep

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Re: Has Curiosity detected methane on Mars?
« Reply #40 on: 10/28/2012 01:44 PM »
Hello, I'm a chemist who lurks the forum.

Aha! Now that's the sort of thing I come here for. Thank you, Tetrakis.

Offline Tetrakis

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Re: Has Curiosity detected methane on Mars?
« Reply #41 on: 10/28/2012 06:59 PM »
Also: Space is cool.  8)

Excellent post. Thanks for de-lurking!

I've been reading the forum for about eight months now, and when I saw the confusion about biochemistry I saw an opening :)

Thanks for the explanations - I always wondered about that.

The chain of reasoning so far went as follows:
- Methane was detected
- Methane has a short half-life due to UV
- Methane is therefore produced
- Let's find out if it is biological in origin or not by using isotope ratios.

What is the reference point for the isotope ratio?  CO2?  Carbon in the ground?

I'm asking, since even though CO2 is not necessarily currently produced, some of it might still have a recent origin. Can we learn something from the isotope ratio of Carbon in the atmospheric CO2?


Astrobiology is far from my field of specialization, but on Earth the choice of standard is pretty arbitrary (usually a specific sample of Cretacious limestone, CaCO3). Carbonate from the atmosphere condenses in the oceans and precipitates as calcium carbonate, so it is considered a "stable" measure of the normal atmospheric distribution; atmospheric ratios can fluctuate greatly depending on the rate at which "buried" biogenic carbon is released. On Mars, methane is oxidized to carbon dioxide by the oxygen released in H2O photolysis; the degree of atmospheric coupling would be small, but it would still present problems because methane production and removal could be temperature dependent.

Buried carbonates have been found on Mars by MRO, Phoenix, and the MERs, indicating the existence of oceans at mild pH in the distant past. It would appear that Phoenix found some calcium carbonate, but based on the lack of isotopic analysis and papers predicting carbonate isotope ratios it appears to me that Phoenix's mass spectrometer didn't have enough resolution to precisely determine the isotope ratio. Such carbonates could act as a good standard against which the time-dependent isotope ratio of atmospheric CO2 and methane could be measured, and fortunately MSL has a solid sample vaporization mass spectrometer which could be used to determine the isotope ratio of a found chunk of a carbonate mineral. It would be nice if the carbonate in martian meteorites could be used, of course, but the small carbonate crystals found in them may have been contaminated by terrestrial carbon. The MERs didn't have mass spectrometers on them, so it would be amazing if MSL found a pretty white chunk of calcium carbonate to pick at. If it did, a martian standard could be used to judge the relative isotope abundance of martian methane.
« Last Edit: 10/28/2012 07:04 PM by Tetrakis »

Offline hop

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Re: Has Curiosity detected methane on Mars?
« Reply #42 on: 10/28/2012 07:28 PM »
- Methane was detected
It's worth remembering these detections are disputed.
Quote
- Methane is therefore produced
Or released from ancient reservoirs.
Quote
- Let's find out if it is biological in origin or not by using isotope ratios.
As other have said, no matter what the result this is likely to only be suggestive one way or the other. A non-detection would also not be immediately definitive, because the previous observations suggested large regional and temporal variations (which raises yet more questions)
Quote
Can we learn something from the isotope ratio of Carbon in the atmospheric CO2?
These have been measured, for example by Phoenix http://uanews.org/node/34019 (paper http://www.sciencemag.org/content/329/5997/1334.short ) The fact that this didn't match predictions hints at the difficulty of drawing hard conclusion from methane isotope ratios.

A final note of caution, IIRC in one of the previous press conferences, the MSL team mentioned that it could take many measurements to tease out the isotope ratios, if they detect methane at all.

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Re: Has Curiosity detected methane on Mars?
« Reply #43 on: 10/28/2012 10:22 PM »
k, again, thanks all.

And I agree about uncertainties of measurements, references, and implications.  Just needed some context.

Good to know they can evaporate solids into the GA.

So another meaningful measurements would be isotope ratios between different types of similarly-aged sedimentary rocks.  If indeed biology is the only thing that can differentiate isotopes, and biology existed, then you'd expect it to contribute different amounts to different amounts of rocks, I'd think.

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Re: Has Curiosity detected methane on Mars?
« Reply #44 on: 10/29/2012 01:15 AM »

Hi Tetrakis

While I have you on the line...could I ask an off-topic question?

Do you know if SAM is equipped to sort out chirality?  As you can imagine, this would be huge if organics such as amino acids are found.  I pawed through the SAM spec without seeing any mention of stereochemistry; I guess just finding something like some amino acids would be exciting enough but as you know without knowing the chirality, the orgin of the amino acids, etc. would be problematical.

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Re: Has Curiosity detected methane on Mars?
« Reply #45 on: 10/29/2012 02:25 AM »

Hi Tetrakis

While I have you on the line...could I ask an off-topic question?

Do you know if SAM is equipped to sort out chirality?  As you can imagine, this would be huge if organics such as amino acids are found.  I pawed through the SAM spec without seeing any mention of stereochemistry; I guess just finding something like some amino acids would be exciting enough but as you know without knowing the chirality, the orgin of the amino acids, etc. would be problematical.

Yes! One of the six gas chromatography columns is ß-cyclodextrin functionalized silica sold by Varian as Chirasildex. It can differentiate volatile organic molecules with very high precision prior to identifying them in the mass spectrometer; if there are two GC peaks with the same mass after being passed through the chiral column, then the compounds are themselves chiral.

By the way, it looks like the SAM team is going to he hosting a Google Hangout space (http://ssed.gsfc.nasa.gov/sam/news.html) tomorrow to talk about the astrobiology mission! Sadly I'm going to have to miss it due to work obligations, but if your interested it would definitely be the place to learn.
« Last Edit: 10/29/2012 02:33 AM by Tetrakis »

Offline Danderman

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Re: Has Curiosity detected methane on Mars?
« Reply #46 on: 10/29/2012 02:48 AM »
AFAIK, there has been no evidence presented in this thread that the rover has detected methane on Mars. There may be such an announcement in the future, but we should not get too ahead of ourselves in presuming that there is methane at the surface of Mars.

Offline Mader Levap

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Re: Has Curiosity detected methane on Mars?
« Reply #47 on: 10/29/2012 03:49 PM »
we should not get too ahead of ourselves in presuming that there is methane at the surface of Mars.
There IS confirmed methane on surface on Mars. Mars Express first detected it. What is disputed is precise amounts and genesis.
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Re: Has Curiosity detected methane on Mars?
« Reply #48 on: 10/31/2012 03:43 PM »
we should not get too ahead of ourselves in presuming that there is methane at the surface of Mars.
There IS confirmed methane on surface on Mars. Mars Express first detected it. What is disputed is precise amounts and genesis.

I believe that there is a peculiar seasonality element also.

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Re: Has Curiosity detected methane on Mars?
« Reply #49 on: 11/02/2012 02:15 PM »
This Nature article says that the first methane results will be announced today:
http://www.nature.com/news/curiosity-set-to-weigh-in-on-mars-methane-puzzle-1.11721

By the way you may notice the exceptionally high quality of this article.  It was written by Eric Hand.  I have been carefully listening to the press's questions at the MSL press conferences and Hand asks the most erudite question of the whole press corp. 
« Last Edit: 11/02/2012 04:04 PM by fthurber »

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Re: Has Curiosity detected methane on Mars?
« Reply #50 on: 11/02/2012 02:31 PM »
Will be waiting with a closed nose plug ;)
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Re: Has Curiosity detected methane on Mars?
« Reply #51 on: 11/02/2012 04:06 PM »
The press conference is not:   http://ustre.am/25IX

But my work has blocked access so I cannot watch it until tonight, alas.  I hope someone can post some commentary shortly.

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Re: Has Curiosity detected methane on Mars?
« Reply #52 on: 11/02/2012 04:37 PM »
BBC just reported Curiosity has not found methane on Mars?

It seems from the report on the link above there was some kind of internal leak inside the vehicle & they still had Earth air in it.
« Last Edit: 11/02/2012 04:42 PM by Star One »

Offline AnalogMan

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Re: Has Curiosity detected methane on Mars?
« Reply #53 on: 11/02/2012 04:51 PM »
NASA'S Curiosity Rover Provides Clues to Changes in Martian Atmosphere
RELEASE : 12-387 Nov. 02, 2012
...
With these initial sniffs of Martian atmosphere, SAM also made the most sensitive measurements ever to search for methane gas on Mars. Preliminary results reveal little to no methane. Methane is of interest as a simple precursor chemical for life. On Earth, it can be produced by either biological or non-biological processes.

Methane has been difficult to detect from Earth or the current generation of Mars orbiters because the gas exists on Mars only in traces, if at all. The Tunable Laser Spectrometer (TLS) in SAM provides the first search conducted within the Martian atmosphere for this molecule. The initial SAM measurements place an upper limit of just a few parts methane per billion parts of Martian atmosphere, by volume, with enough uncertainty that the amount could be zero.

"Methane is clearly not an abundant gas at the Gale Crater site, if it is there at all. At this point in the mission we're just excited to be searching for it," said SAM TLS lead Chris Webster of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "While we determine upper limits on low values, atmospheric variability in the Martian atmosphere could yet hold surprises for us."

...

http://www.nasa.gov/home/hqnews/2012/oct/HQ_12-387_Mars_Atmosphere.html

Offline Star One

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Re: Has Curiosity detected methane on Mars?
« Reply #54 on: 11/02/2012 04:56 PM »
All this must decrease the likelihood of any kind of life I would think.

Offline stone

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Re: Has Curiosity detected methane on Mars?
« Reply #55 on: 11/02/2012 04:59 PM »
Like what I heared since the Methane on Mars Conference in Italy some time ago most scientists more sceptical to the Methane story than the public, and they were right.

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Re: Has Curiosity detected methane on Mars?
« Reply #56 on: 11/02/2012 05:01 PM »
Like what I heared since the Methane on Mars Conference in Italy some time ago most scientists more sceptical to the Methane story than the public, and they were right.

So all that taxpayers money spent on sending MAVEN to Mars next year is a waste of money then?
« Last Edit: 11/02/2012 05:01 PM by Star One »

Offline stone

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Re: Has Curiosity detected methane on Mars?
« Reply #57 on: 11/02/2012 05:04 PM »
Like what I heared since the Methane on Mars Conference in Italy some time ago most scientists more sceptical to the Methane story than the public, and they were right.

So all that taxpayers money spent on sending MAVEN to Mars next year is a waste of money then?

MAVEN was never a methane searcher. It was a atmosphere evolution probe. Loos of gas due to solar wind and influence on the upper atmosphere was the goal.

Offline Star One

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Re: Has Curiosity detected methane on Mars?
« Reply #58 on: 11/02/2012 05:05 PM »
Like what I heared since the Methane on Mars Conference in Italy some time ago most scientists more sceptical to the Methane story than the public, and they were right.

So all that taxpayers money spent on sending MAVEN to Mars next year is a waste of money then?

MAVEN was never a methane searcher. It was a atmosphere evolution probe. Loos of gas due to solar wind and influence on the upper atmosphere was the goal.

I am aware of that but it has also been sold online on the point of searching for Methane.

Quote
In 2013 NASA will launch the MAVEN orbiter mission to Mars, which will characterize the current atmosphere and how molecules are lost from its upper atmosphere. MAVEN's measurements will provide additional scientific context with which to test models for methane formation in the current Mars era.

http://science.discovery.com/stories/mars/questions/questions.html
« Last Edit: 11/02/2012 05:07 PM by Star One »

Offline stone

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Re: Has Curiosity detected methane on Mars?
« Reply #59 on: 11/02/2012 05:18 PM »
Like what I heared since the Methane on Mars Conference in Italy some time ago most scientists more sceptical to the Methane story than the public, and they were right.

So all that taxpayers money spent on sending MAVEN to Mars next year is a waste of money then?

MAVEN was never a methane searcher. It was a atmosphere evolution probe. Loos of gas due to solar wind and influence on the upper atmosphere was the goal.

I am aware of that but it has also been sold online on the point of searching for Methane.

Quote
In 2013 NASA will launch the MAVEN orbiter mission to Mars, which will characterize the current atmosphere and how molecules are lost from its upper atmosphere. MAVEN's measurements will provide additional scientific context with which to test models for methane formation in the current Mars era.

http://science.discovery.com/stories/mars/questions/questions.html

In that time ESA was asking us if we will be a methane sensitive instrument. We denied. The agencies are like dogs, if the public throws a stick (we want water on mars, or we want methane on masr) they run. Most of the things in the media is half true or 1000% bigger than it should be (arsenic based lifeforms).
« Last Edit: 11/02/2012 05:18 PM by stone »

Offline Blackstar

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Re: Has Curiosity detected methane on Mars?
« Reply #60 on: 11/02/2012 06:51 PM »
I am aware of that but it has also been sold online on the point of searching for Methane.


"MAVEN's measurements will provide additional scientific context with which to test models for methane formation in the current Mars era."

Read that quoted statement more carefully. It doesn't say that MAVEN would look for methane. It says that it would "provide additional scientific context" to "test models for methane formation." Put another way, that would allow scientists to rule out some things and include other things in their models.

Trace Gas Orbiter, however, had a more direct role in methane detection. MAVEN does not.

It's also worth understanding the political and public relations environment of Discovery class missions like MAVEN. Their sponsors often make broader claims for them than are actually justified. For example, Discovery class missions are not required to do science that is in the planetary science decadal survey. But they often try to tie what they are doing to the goals established in the decadal survey. Everybody understands how this game is played and the players automatically account for it. It's not a big deal.

Offline Blackstar

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Re: Has Curiosity detected methane on Mars?
« Reply #61 on: 11/02/2012 06:52 PM »
I did not get to listen to the press conference, but this is rather disappointing. Clearly the buzz that was, er, buzzing, the past few weeks indicated that at least some people thought that they had found something. They would not have been buzzing over a negative result. But obviously they checked their data more carefully and came up zero.

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Re: Has Curiosity detected methane on Mars?
« Reply #62 on: 11/02/2012 07:43 PM »
Like what I heared since the Methane on Mars Conference in Italy some time ago most scientists more sceptical to the Methane story than the public, and they were right.

So all that taxpayers money spent on sending MAVEN to Mars next year is a waste of money then?

Not at all.  There are plenty of good reasons to send MAVEN to Mars even if it cannot directly search for methane.

Note: It was already known that Gale crater did not appear to be a hot spot for methane so these results are not too surprising.  A tiny bit disappointing but not surprising.  So just because there is no or almost no methane in Gale does not mean there is no methane on Mars as a whole.  It is still worthwhile to search for methane on Mars.


« Last Edit: 11/02/2012 07:48 PM by fthurber »

Offline Star One

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Re: Has Curiosity detected methane on Mars?
« Reply #63 on: 11/02/2012 08:00 PM »
I am aware of that but it has also been sold online on the point of searching for Methane.


"MAVEN's measurements will provide additional scientific context with which to test models for methane formation in the current Mars era."

Read that quoted statement more carefully. It doesn't say that MAVEN would look for methane. It says that it would "provide additional scientific context" to "test models for methane formation." Put another way, that would allow scientists to rule out some things and include other things in their models.

Trace Gas Orbiter, however, had a more direct role in methane detection. MAVEN does not.

It's also worth understanding the political and public relations environment of Discovery class missions like MAVEN. Their sponsors often make broader claims for them than are actually justified. For example, Discovery class missions are not required to do science that is in the planetary science decadal survey. But they often try to tie what they are doing to the goals established in the decadal survey. Everybody understands how this game is played and the players automatically account for it. It's not a big deal.

I dug that particular article up in under sixty seconds using a Google search and no it wasn't that good an example of my argument, but it did give a flavor how things like this get conflated on the net.

I guess i am such kind of disappointed by the news we have had today on this particular issue and it has put me into a negative frame of mind about the whole prospect of finding anything interesting like this on Mars.
« Last Edit: 11/02/2012 08:02 PM by Star One »

Offline Blackstar

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Re: Has Curiosity detected methane on Mars?
« Reply #64 on: 11/02/2012 08:55 PM »
I guess i am such kind of disappointed by the news we have had today on this particular issue and it has put me into a negative frame of mind about the whole prospect of finding anything interesting like this on Mars.

Go to the pub.

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Re: Has Curiosity detected methane on Mars?
« Reply #65 on: 11/02/2012 09:09 PM »
Well, we do not yet have a base line to know if methane does not suddenly appear in Gale crater. It be more interesting to see if it is completely negative after a full martian year. A seasonal methane signature would be most interesting...
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Offline Robert Thompson

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Re: Has Curiosity detected methane on Mars?
« Reply #66 on: 11/02/2012 09:22 PM »
It is patently obvious that NASA is covering something up. The people have a right to know.

Offline KelvinZero

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Re: Has Curiosity detected methane on Mars?
« Reply #67 on: 11/02/2012 11:16 PM »
It is patently obvious that NASA is covering something up. The people have a right to know.
They are probably just embarrassed to admit that due to another clean room mess up Mars has been accidentally contaminated with five million cows. Any cows will have to be filtered from future measurements as probably having come from earth.

Offline neilh

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Re: Has Curiosity detected methane on Mars?
« Reply #68 on: 11/02/2012 11:32 PM »
Well, we do not yet have a base line to know if methane does not suddenly appear in Gale crater. It be more interesting to see if it is completely negative after a full martian year. A seasonal methane signature would be most interesting...

Indeed. Am I correct in my understanding that Gale crater is currently in the equivalent of Martian winter?
« Last Edit: 11/02/2012 11:36 PM by neilh »
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Re: Has Curiosity detected methane on Mars?
« Reply #69 on: 11/02/2012 11:33 PM »
It is patently obvious that NASA is covering something up. The people have a right to know.

Yes, that must be it...
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Offline yg1968

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Re: Has Curiosity detected methane on Mars?
« Reply #70 on: 11/03/2012 12:00 AM »
Here is an mp3 file of the press conference:
http://spaceref.com/podcasts/spacetalk.xml

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Re: Has Curiosity detected methane on Mars?
« Reply #71 on: 11/03/2012 01:18 AM »
News release 2012-348                                                                    Nov. 2, 2012

NASA Rover Finds Clues to Changes in Mars' Atmosphere

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2012-348&cid=release_2012-348

PASADENA, Calif. -- NASA's car-sized rover, Curiosity, has taken significant steps toward understanding how Mars may have lost much of its original atmosphere.

Learning what happened to the Martian atmosphere will help scientists assess whether the planet ever was habitable. The present atmosphere of Mars is 100 times thinner than Earth's.

A set of instruments aboard the rover has ingested and analyzed samples of the atmosphere collected near the "Rocknest" site in Gale Crater where the rover is stopped for research. Findings from the Sample Analysis at Mars (SAM) instruments suggest that loss of a fraction of the atmosphere, resulting from a physical process favoring retention of heavier isotopes of certain elements, has been a significant factor in the evolution of the planet. Isotopes are variants of the same element with different atomic weights.

Initial SAM results show an increase of five percent in heavier isotopes of carbon in the atmospheric carbon dioxide compared to estimates of the isotopic ratios present when Mars formed. These enriched ratios of heavier isotopes to lighter ones suggest the top of the atmosphere may have been lost to interplanetary space. Losses at the top of the atmosphere would deplete lighter isotopes. Isotopes of argon also show enrichment of the heavy isotope, matching previous estimates of atmosphere composition derived from studies of Martian meteorites on Earth.

Scientists theorize that in Mars' distant past its environment may have been quite different, with persistent water and a thicker atmosphere. NASA's Mars Atmosphere and Volatile Evolution, or MAVEN, mission will investigate possible losses from the upper atmosphere when it arrives at Mars in 2014.

With these initial sniffs of Martian atmosphere, SAM also made the most sensitive measurements ever to search for methane gas on Mars. Preliminary results reveal little to no methane. Methane is of interest as a simple precursor chemical for life. On Earth, it can be produced by either biological or non-biological processes.

Methane has been difficult to detect from Earth or the current generation of Mars orbiters because the gas exists on Mars only in traces, if at all. The Tunable Laser Spectrometer (TLS) in SAM provides the first search conducted within the Martian atmosphere for this molecule. The initial SAM measurements place an upper limit of just a few parts methane per billion parts of Martian atmosphere, by volume, with enough uncertainty that the amount could be zero.

"Methane is clearly not an abundant gas at the Gale Crater site, if it is there at all. At this point in the mission we're just excited to be searching for it," said SAM TLS lead Chris Webster of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "While we determine upper limits on low values, atmospheric variability in the Martian atmosphere could yet hold surprises for us."

In Curiosity's first three months on Mars, SAM has analyzed atmosphere samples with two laboratory methods. One is a mass spectrometer investigating the full range of atmospheric gases. The other, TLS, has focused on carbon dioxide and methane. During its two-year prime mission, the rover also will use an instrument called a gas chromatograph that separates and identifies gases. The instrument also will analyze samples of soil and rock, as well as more atmosphere samples.

"With these first atmospheric measurements we already can see the power of having a complex chemical laboratory like SAM on the surface of Mars," said SAM Principal Investigator Paul Mahaffy of NASA's Goddard Space Flight Center in Greenbelt, Md. "Both atmospheric and solid sample analyses are crucial for understanding Mars' habitability."

SAM is set to analyze its first solid sample in the coming weeks, beginning the search for organic compounds in the rocks and soils of Gale Crater. Analyzing water-bearing minerals and searching for and analyzing carbonates are high priorities for upcoming SAM solid sample analyses.

Researchers are using Curiosity's 10 instruments to investigate whether areas in Gale Crater ever offered environmental conditions favorable for microbial life. JPL, a division of the California Institute of Technology in Pasadena, manages the project for NASA's Science Mission Directorate, Washington, and built Curiosity. The SAM instrument was developed at Goddard with instrument contributions from Goddard, JPL and the University of Paris in France.

For more information about Curiosity and its mission, visit: http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl .

You can follow the mission on Facebook and Twitter at: http://www.facebook.com/marscuriosity and http://www.twitter.com/marscuriosity .

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
[email protected]

Nancy Neal Jones 301-286-0039
NASA Goddard Space Flight Center, Greenbelt, Md.
[email protected]

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
[email protected]
- end -
Tony De La Rosa

Offline Blackstar

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Re: Has Curiosity detected methane on Mars?
« Reply #72 on: 11/03/2012 01:22 AM »
It is patently obvious that NASA is covering something up. The people have a right to know.

Space aliens.

Flatulent ones.

The worst kind.
« Last Edit: 11/03/2012 01:25 AM by Blackstar »

Offline hop

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Re: Has Curiosity detected methane on Mars?
« Reply #73 on: 11/03/2012 01:26 AM »
Here is an mp3 file of the press conference:
http://spaceref.com/podcasts/spacetalk.xml
Like most of the MSL telecons, it's also archived on their ustream channel http://www.ustream.tv/recorded/26637100 - there's no real video, but the speakers slides are shown.

Eric Hand has a nice write up:
http://www.nature.com/news/nasa-rover-finds-no-methane-on-mars-yet-1.11730

I expect the earlier "buzz" was from the first two runs that still had traces of earth air.

Offline Robert Thompson

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Re: Has Curiosity detected methane on Mars?
« Reply #74 on: 11/03/2012 03:31 AM »
The Klingon proverb is, better to survive in dirty drawers than to die in clean. Would EML2 make a good clean room?

Offline RigelFive

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Re: Has Curiosity detected methane on Mars?
« Reply #75 on: 11/03/2012 04:24 AM »
Quote
With these initial sniffs of Martian atmosphere, SAM also made the most sensitive measurements ever to search for methane gas on Mars. Preliminary results reveal little to no methane.

It seems rather intuitive at this moment that if we cannot detect methane in a short amount of time with a nuclear powered scientific probe, this has a major impact to the potential configuration of manned propulsion systems envisioned for 21st century missions to Mars. 

There is no way a 21st century manned mission can expend unquantifiable amounts of energy looking around the surface of Mars for rocket fuel.

We were duped yet again and have no relevant return on investment for the $2.6B dollar MSL probe toward future manned exploration on Mars!

I feel that this is very very unfortunate news. 

My favorite Klingon proverb is "the dirt underneath my fingernails could melt dilithium"

Offline KelvinZero

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Re: Has Curiosity detected methane on Mars?
« Reply #76 on: 11/03/2012 04:57 AM »
Hi RigelFive,
Im going to take your post at face value. Sorry if you are being ironic!  :)

Don't panic.
There was never any expectation or implication of locating sufficient methane on mars for propellant. The search for methane is totally unrelated to this.

There is however a plan to create methane and oxygen for propellant from carbon dioxide which we know to be the main constituent of the atmosphere of Mars, plus hydrogen which could be sent from earth or also created on mars from ice.

Offline spectre9

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Re: Has Curiosity detected methane on Mars?
« Reply #77 on: 11/03/2012 05:32 AM »
Most of the methane comes from Tharsis.

Sometimes I like to imagine there are Martians living beneath those peaks in ancient lava tubes.

Offline Star One

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Re: Has Curiosity detected methane on Mars?
« Reply #78 on: 11/03/2012 09:35 AM »
Most of the methane comes from Tharsis.

Sometimes I like to imagine there are Martians living beneath those peaks in ancient lava tubes.

Reading around it is pointed out that it is currently the Martian winter & where Curiosity is based is not known as a hotspot for Methane anyway. So it would seem that there is probably more distance to go in this matter.

Is there any planned missions to Tharsis as if that's where the Methane is why not send something specifically to that location?

Offline fthurber

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Re: Has Curiosity detected methane on Mars?
« Reply #79 on: 11/04/2012 01:09 PM »
Quote
With these initial sniffs of Martian atmosphere, SAM also made the most sensitive measurements ever to search for methane gas on Mars. Preliminary results reveal little to no methane.
...
We were duped yet again and have no relevant return on investment for the $2.6B dollar MSL probe toward future manned exploration on Mars!
...

Not at all!  MSL has been very successful (and the mission is just starting) and well worth the investment.  Just because Mars turns out to not be what we wanted it to be does not make the mission a failure.  Let me repeat; MSL has been highly successful. Getting all its complicated systems to work together has been an engineering marvel and the scientific payoff is just starting...MSL will re-write our understanding of Mars.

BTW MSL cost about 1.8B.  The rest was launch and operations.   It created thousands of high-quality jobs.


« Last Edit: 11/04/2012 09:35 PM by fthurber »

Offline TheFallen

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Re: Has Curiosity detected methane on Mars?
« Reply #80 on: 11/04/2012 05:21 PM »
We were duped yet again and have no relevant return on investment for the $2.6B dollar MSL probe toward future manned exploration on Mars!

Duped? MSL's main objective is to see if the environment it's in was ever hospitable to life (RE: Look for geological features containing clay material)...not to primarily look for methane in the atmosphere. That's what the MAVEN mission that launches next year is for.
« Last Edit: 11/04/2012 05:24 PM by TheFallen »

Offline Blackstar

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Re: Has Curiosity detected methane on Mars?
« Reply #81 on: 11/05/2012 02:10 AM »
He's trolling. Just don't bite.

Offline kevin-rf

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Re: Has Curiosity detected methane on Mars?
« Reply #82 on: 11/05/2012 11:53 AM »
He's trolling. Just don't bite.
You mean Martians don't taste like chicken?
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Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #83 on: 11/05/2012 08:21 PM »
Space aliens.

Flatulent ones.

The worst kind.

All I asked was, why didn't they purge the methane chamber of well, methane, before they left?

I didn't mention cows.  At all.

What next?  Silent but deadly jokes?
Sometimes I just flat out don't get it.

Offline Blackstar

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Re: Has Curiosity detected methane on Mars?
« Reply #84 on: 11/06/2012 12:41 AM »
Space aliens.

Flatulent ones.

The worst kind.

All I asked was, why didn't they purge the methane chamber of well, methane, before they left?

I didn't mention cows.  At all.

That's okay. We know that you were thinking it.

Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #85 on: 11/06/2012 12:24 PM »
We know that you were thinking it.

What!!??  You all have mental apathy?

Are you all from Nirubu perchance?
Sometimes I just flat out don't get it.

Offline fthurber

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Re: Has Curiosity detected methane on Mars?
« Reply #86 on: 11/08/2012 01:59 AM »
I am actually quite encouraged by the non-detection of methane by TLS...at least at the detection limit.  The fact that they were able to detect it in trapped FL air and then got no reading after purging makes me think the TLS is working well.

It must be very hard to avoid contamination with an instrument that is so sensitive but it seems that the team has done a great job. 

I look forward to methane tests through the whole martian year; maybe methane is seasonal in Gale.

Offline RigelFive

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Re: Has Curiosity detected methane on Mars?
« Reply #87 on: 11/08/2012 06:15 AM »
Hi RigelFive,
Im going to take your post at face value. Sorry if you are being ironic!  :)

Don't panic.
There was never any expectation or implication of locating sufficient methane on mars for propellant. The search for methane is totally unrelated to this.

There is however a plan to create methane and oxygen for propellant from carbon dioxide which we know to be the main constituent of the atmosphere of Mars, plus hydrogen which could be sent from earth or also created on mars from ice.
You say that there is actually a way, some type of process, or by chance that propulsion fuel grade methane on Mars from carbon dioxide?  I'd love to understand how?

Pardon my negative mood in the prior post. 

This concept has been kicked around since Zubrin.  I feel that methane from organic/biological origins seems too remote of a possibility.

My belief is that a methane discovery is essential for mars manned propulsion projects.

XCOR
http://www.xcor.com/products/engines/5M15_LOX-Methane_rocket_engine.html

There was another methane engine at Aerojet that seems to have recently won some recognition recognition from NASA.

Offline KelvinZero

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Re: Has Curiosity detected methane on Mars?
« Reply #88 on: 11/08/2012 07:15 AM »
My belief is that a methane discovery is essential for mars manned propulsion projects.

XCOR
http://www.xcor.com/products/engines/5M15_LOX-Methane_rocket_engine.html

There was another methane engine at Aerojet that seems to have recently won some recognition recognition from NASA.

I suspect that a lot of the interest in Methane as a rocket fuel is because we are confident that we can create it on Mars from CO2 (and there is absolutely no doubt that the martian atmosphere is mostly CO2)

Here is a link.
http://en.wikipedia.org/wiki/Sabatier_reaction#Manufacturing_propellant_on_Mars
Apparently this reaction is extremely well understood and has been used since the nineteenth century. I have never heard any serious question of its plausibility. As the saying goes: "This is not rocket science".

The current search for methane has nothing to do with exploiting it for rocket fuel. I think the hoped-for amounts were minuscule.. 30 parts per billion or something? Apparently methane could have been an indicator of life. It is probably all discussed in this thread somewhere.

Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #89 on: 11/08/2012 01:44 PM »
You say that there is actually a way, some type of process, or by chance that propulsion fuel grade methane on Mars from carbon dioxide?

Second hit on the googol:

Sunlight turns carbon dioxide to methane

Piece of cake in principle.  Doesn't meant that I, or anybody else can do it at this time.
Sometimes I just flat out don't get it.

Offline iamlucky13

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Re: Has Curiosity detected methane on Mars?
« Reply #90 on: 11/08/2012 07:59 PM »
The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2012-348&cid=release_2012-348

...The present atmosphere of Mars is 100 times thinner than Earth's...

Gah! It bugs me enough when ordinary journalists do this. Now even JPL is doing it.

Mars has negative atmosphere!

All I asked was, why didn't they purge the methane chamber of well, methane, before they left?

Serious answer then: Suppose they didn't, what does that imply? Possible confusion of results, but we're talking about gasses here. Baring any reason for the chamber to have a particularly strong affinity for methane, the contamination is gradually reduced, and this appears to be what they are observing.

There also may have been practical issues in doing so related to the design of SAM. I'm not familiar enough with SAM to say one way or the other, but I can easily envision complications with purging the chamber and ensuring it avoids re-contamination.

Actually, the practicality angle is discussed very generally on this page in the interview with Therese Errigo:
http://ssed.gsfc.nasa.gov/sam/engineerteam.html

A lot more detail in this paper, although methane is not specifically addressed:
http://www.ingeloes.com/papers/2008/2008-tenkate-etal-Mitigation%20of%20the%20Impact%20of%20Terrestrial%20Contamination%20on%20Organic%20Measurements%20from%20the%20Mars%20Science%20Laboratory.pdf

This concept has been kicked around since Zubrin.  I feel that methane from organic/biological origins seems too remote of a possibility.

Many others agree with you, but it is not something that can be clearly ruled out, and there are good reasons to consider it may exist or have in the past existed. So we look, and regardless of whether we find it or not, we've refined our knowledge.

Quote
My belief is that a methane discovery is essential for mars manned propulsion projects.

Fortunately, this is incorrect. There are several hypothetical fuels that can be produced on Mars, of which methane is one of the easiest. The link KelvinZero posted explains it fairly well.

Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #91 on: 11/08/2012 08:10 PM »
All I asked was, why didn't they purge the methane chamber of well, methane, before they left?

Serious answer then: Suppose they didn't, what does that imply? Possible confusion of results, but we're talking about gasses here. Baring any reason for the chamber to have a particularly strong affinity for methane, the contamination is gradually reduced, and this appears to be what they are observing.

There also may have been practical issues in doing so related to the design of SAM. I'm not familiar enough with SAM to say one way or the other, but I can easily envision complications with purging the chamber and ensuring it avoids re-contamination.

Thanks for the serious answer.  "Possible confusion of results" is exactly the problem.  That they are now gradually reducing the contamination, demonstrates that they are fixing a problem that they brought with them.  Again, although methane is a gas, it's can be differentiated by the isotopic tests gone into detail up the thread a bit.  What these complications might have been would be good to know something about.

The first response to my question, however, was an emotional ad hominem supported by an appeal to authority; educating nobody. 
Sometimes I just flat out don't get it.

Offline catdlr

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Re: Has Curiosity detected methane on Mars?
« Reply #92 on: 11/10/2012 04:01 AM »
SAM Sniffs Mars' Atmosphere

Published on Nov 9, 2012 by JPLnews

The Curiosity rover's Sample Analysis at Mars (SAM) instruments make the most sensitive measurements ever to search for methane gas on the Red Planet.

« Last Edit: 11/10/2012 04:02 AM by catdlr »
Tony De La Rosa

Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #93 on: 11/10/2012 03:31 PM »
The update was an excellent summary of capability.
« Last Edit: 11/11/2012 02:15 PM by JohnFornaro »
Sometimes I just flat out don't get it.

Offline RigelFive

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Re: Has Curiosity detected methane on Mars?
« Reply #94 on: 11/11/2012 04:06 AM »
The update was an excellent summary of capaility.
Ok I get it.  So in her "video" (*cough* infomercial) she dropped the hint that the methane they are looking for may be only detected in certain seasons.  So right around the next warming season (*cough* congressional budget season) we actually could catch a little whiff (hnnnnnnnn'kpt) of the Martian methane...

Methane has already been detected from Earth in very very very very small quantities.  That is just what I needed to KNOW!

Offline Tetrakis

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Re: Has Curiosity detected methane on Mars?
« Reply #95 on: 11/11/2012 04:29 AM »
The update was an excellent summary of capaility.
Ok I get it.  So in her "video" (*cough* infomercial) she dropped the hint that the methane they are looking for may be only detected in certain seasons.  So right around the next warming season (*cough* congressional budget season) we actually could catch a little whiff (hnnnnnnnn'kpt) of the Martian methane...

Methane has already been detected from Earth in very very very very small quantities.  That is just what I needed to KNOW!

For a Star Trek fan, you have very little respect for scientists. Are you seriously suggesting that the DPI of this experiment would fabricate evidence to please political masters? I hate to break it to you, but I doubt that she spends her time cackling madly and twirling a mirror-universe mustache.

Detecting martian methane on mars with an instrument as sensitive as the TLS would be useful because it would present the opportunity to quantify the isotopic ratio in methane relative to that in atmospheric carbon dioxide. Very high resolutions are required for spectroscopic determination of isotope ratios, and those can be easily acquired when you have a very strong local light source (a laser) rather than a weak nonlocal light source (the sun's light passing through the martian atmosphere and being reflected to earth).

Edit: A quick trip through the literature yielded a few good papers everyone interested in the thread should read.

Review of ground-based detection efforts for martian gases:
http://www.sciencedirect.com/science/article/pii/S0032063306001814

Paper demonstrating martian methane from an earth-based telescope:
http://www.sciencedirect.com.proxy.lib.umich.edu/science/article/pii/S0019103504002222

Methane has been known to be on mars for years now. It is impossible to quantify isotope ratios from current data due to the extremely low concentrations and (relatively) low light intensity and coherence available to date. A real to goodness, lab quality, high power spectrometer on the surface of mars is useful... Please do not start spouting innuendo until you at least familiarize yourself with the literature.
« Last Edit: 11/11/2012 05:08 AM by Tetrakis »

Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #96 on: 11/11/2012 02:44 PM »
I doubt that she spends her time cackling madly and twirling a mirror-universe mustache.

Huh.  The video you saw must have been shorter, then.  BTW, I saw it on October 31st... at midnight...

Seriously, you need to be a bit more specific about "innuendo", if this is important to your argument. 

Factually, the "update" was a concise, well put summary of the rover's capability, and did not address any current activity regarding the search for methane, including the recent methane purge.  Sadly, for "marketing" reasons, which are not and were not under the purview of the narrator, the video was billed as an "update", when everything mentioned in the video has been known to followers for well over two years.  New observers of the mission may readily accept the term "update", but hey:  A lot of people are late to the party.

Again, the crux of my first question was very simple:  Why not purge the methane chamber of methane before leaving?

Answer: We've run out of time for questions.
Sometimes I just flat out don't get it.

Offline eeergo

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Re: Has Curiosity detected methane on Mars?
« Reply #97 on: 11/12/2012 01:13 AM »

Again, the crux of my first question was very simple:  Why not purge the methane chamber of methane before leaving?

Answer: We've run out of time for questions.

The answer may not be as simple as the question, but I don't think anybody is trying to avoid it, it's just not a one-liner answer.

While I have no insider information about this instrument, it's clear it might have been impossible to keep all the ensemble (TLS instrument+plumbing) in vacuum since the last thermal vacuum test on Earth until launch. Even if once assembled it was kept in vacuum -which I don't know if it was designed to be-, some parts might have been exposed to terrestrial air with no "deep cleansing" afterwards: with this I mean long vacuum exposure, with inert flushings (He or N2) and considerable heating cycles.

Methane can be adsorbed in metals* (SAM is described to be mainly aluminium with gold plating**) and there might be parts with plastics or other materials exposed (seals, valves...?) which might adsorb even better. From working with vacuum systems, I know how "pockets" of gases can become trapped in intricate structures and how only long, deep vacuum and thermal cycles may bring them out.

With all this in mind, a look at the figures also puts it in perspective: we're talking about ~7-8 ppb***. Atmospheric concentration is ~1-2 parts per Million. That means there was a reduction of a factor of ~500. Moreover, these concentrations were only measured in the first two (of four) uses of the instrument, after a nice deal of time, vibration and thermal changes had taken place since the last possible flushing. I haven't tried to estimate the numbers, but perhaps just possible adsorption/micropokets of gas on the valves' edge surfaces could account for a good amount of that.

Again, I'm not an insider to any information about this instrument and maybe even those methane peaks in the first two measurements could have been avoided with more careful flushing, but it doesn't seem reasonable to be that picky with something as obvious as proper cleaning in such a complex instrument :)

*CH4 adsorption in Au: http://prb.aps.org/abstract/PRB/v61/i7/p4941_1
**Nice free paper about SAM's design and calibrations: http://www.springerlink.com/content/p26510688kg4q808/
***Nature's press article : http://www.nature.com/news/nasa-rover-yet-to-find-methane-on-mars-1.11730
-DaviD-

Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #98 on: 11/12/2012 02:01 PM »
Why not purge the methane chamber of methane before leaving?

The answer may not be as simple as the question, but I don't think anybody is trying to avoid it, it's just not a one-liner answer.

Just as an aside, there is some "history" between several of the posters above, which detracts somewhat from a helpful discussion.  As always, sometimes there are complex answers to simple questions.  Thanks for trying.

Quote
... it might have been impossible to keep all the ensemble (TLS instrument+plumbing) in vacuum since the last thermal vacuum test on Earth until launch.

If I were setting up a sensitive methane sniffing experiment,  I would be sure that my methane chamber be as clean as I could make it.  After the last thermal vacuum test, fill it with argon or something, at atmospheric pressure.  You'd want to get to your site and not be sidetracked by anomalous readings.

One of the things not being answered on this thread is why this suggestion is so poorly conceived, and also uncalled for.  What appears to have taken place is some line of reasoning to this effect:  We have a sensitive methane sniffer.  We have designed into it the ability to completely or sufficiently, purge it's sniffer on site, as part of the on-site calibration process.  This is a benefit to the mission, since it saves the time and money otherwise required for Earthly purging and filling of the chamber, and ensures that we will get accurate results.

Quote
Methane can be adsorbed in metals* (SAM is described to be mainly aluminium with gold plating**) ...

No doubt that adsorption effects have been accounted for.  [Ominous pause.]  Or have they?

Quote
With all this in mind, a look at the figures also puts it in perspective: we're talking about ~7-8 ppb***. Atmospheric concentration is ~1-2 parts per Million. .. these concentrations were only measured in the first two (of four) uses of the instrument, after a nice deal of time, vibration and thermal changes had taken place since the last possible flushing. I haven't tried to estimate the numbers, but perhaps just possible adsorption/micropokets of gas on the valves' edge surfaces could account for a good amount of that.

IDK.  If you're looking for a flu virus, you generally sterilize your instruments before looking.  [BTW, I am not still talking about bacterial sterility of that methane; that was uhhh... the keyboard speaking.]  If you're looking for new methane, you don't bring old methane along with you on the journey.  I mean, when you're building the device, why get all dolled up in these suits?  See below.

Quote
... maybe even those methane peaks in the first two measurements could have been avoided with more careful flushing, but it doesn't seem reasonable to be that picky with something as obvious as proper cleaning in such a complex instrument.

It doesn't seem reasonable to be that picky with something as obvious as proper cleaning in such a complex instrument?

Huh?  Clean instruments are not that important?

Thanks for the papers.

Sometimes I just flat out don't get it.

Offline eeergo

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Re: Has Curiosity detected methane on Mars?
« Reply #99 on: 11/12/2012 02:59 PM »

If I were setting up a sensitive methane sniffing experiment,  I would be sure that my methane chamber be as clean as I could make it.  After the last thermal vacuum test, fill it with argon or something, at atmospheric pressure.  You'd want to get to your site and not be sidetracked by anomalous readings.

One of the things not being answered on this thread is why this suggestion is so poorly conceived, and also uncalled for.  What appears to have taken place is some line of reasoning to this effect:  We have a sensitive methane sniffer.  We have designed into it the ability to completely or sufficiently, purge it's sniffer on site, as part of the on-site calibration process.  This is a benefit to the mission, since it saves the time and money otherwise required for Earthly purging and filling of the chamber, and ensures that we will get accurate results. [...]

No doubt that adsorption effects have been accounted for.  [Ominous pause.]  Or have they?

So, to your judgement, that line of reasoning (which provides no adverse effects on the results and is more practical) is flawed?

The problem with the "obvious" solutions is that they may bring more problems than just risking a very minor contamination that can be easily flushed and accounted for upon landing. Inert fillup with Earth's ambient pressure will lead to overpressurization and an energetic gas release at the instrument's first use. Filling up with Mars' pressure will be almost the same than leaving it in vacuum (which again may or may not be unfeasible or have other ill-effects with this instrument) and may impede good ventilation to the outside in the first few measurements. I would be very interested in knowing about the calibration safeguards agains Earth gas contaminants too, and I don't intend to have a blind trust in the builders, but I don't think suggesting somebody overlooked something pretty basic as adsorption or eliminating the problem with a simple Ar flush is the proper way of asking for details.

Quote
IDK.  If you're looking for a flu virus, you generally sterilize your instruments before looking.  [BTW, I am not still talking about bacterial sterility of that methane; that was uhhh... the keyboard speaking.]  If you're looking for new methane, you don't bring old methane along with you on the journey.  I mean, when you're building the device, why get all dolled up in these suits?  See below.

Equipment sterilization (removal or major destruction of the great majority of viruses -not necessarily every single one of them-) is not comparable to completely eliminating a ubiquotous atmospheric gas... in addition to all the mechanisms I suggested, even the rover may be outgassing some of it!

To illustrate, an experiment I work with is contaminated with 85Kr, a much rarer gas than CH4 created mainly during the Cold War nuclear tests (and to some extent by nuclear reactors), even though it has been isolated under a mountain and flushed innumerable times with special (unbreathable) synthetic air, during more than 3 years. And it still gives problems analyzing the signal we're looking for!

Quote
Quote
... maybe even those methane peaks in the first two measurements could have been avoided with more careful flushing, but it doesn't seem reasonable to be that picky with something as obvious as proper cleaning in such a complex instrument.

It doesn't seem reasonable to be that picky with something as obvious as proper cleaning in such a complex instrument?

Huh?  Clean instruments are not that important?

Thanks for the papers.

Perhaps my wording is confusing: I meant it's not reasonable to be that picky and assume somebody has made a major mistake, with something as basic, obvious and important as proper cleaning in a cutting-edge instrument.

My point is: why this interest with trying to imply negligence in a project many professionals have spent years carefully working with? Again, I would also be delighted to hear about SAM's flushing and contamination discrimination procedures, but I would try not to imply that having a trace non-reactive contamination in the first two measurements necessarily means a gross mistake was made.
-DaviD-

Offline JohnFornaro

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Re: Has Curiosity detected methane on Mars?
« Reply #100 on: 11/12/2012 03:58 PM »
So, to your judgement, that line of reasoning (which provides no adverse effects on the results and is more practical) is flawed?

I have no idea.  My question has not been answered.

Quote
The problem with the "obvious" solutions is that they may bring more problems than just risking a very minor contamination that can be easily flushed and accounted for upon landing. Inert fillup with Earth's ambient pressure will lead to overpressurization and an energetic gas release at the instrument's first use.

So generally true.  There's no information on this thread regarding whether or not the device could maintain Earth's ambient pressure thruout the journey, even if filled with Ar.  Neither has the starting pressure been specified.  All that's been unofficially mentioned is that terrestrial methane was clearly present in the chamber, and that four on-site purges have been made.

Quote
Filling up with Mars' pressure will be almost the same than [as?] leaving it in vacuum (which again may or may not be unfeasible or have other ill-effects with this instrument) and may impede good ventilation to the outside in the first few measurements. I would be very interested in knowing about the calibration safeguards agains Earth gas contaminants too, and I don't intend to have a blind trust in the builders, but I don't think suggesting somebody overlooked something pretty basic as adsorption or eliminating the problem with a simple Ar flush is the proper way of asking for details.

It's a shame that there are so many tender egos which must be assuaged.  Mea culpa on my intial tone of voice, which I acknowledged already in the thread above.  Can we move beyond a discussion about me? 

From what hasn't been said on the thread, there was no Ar flush.  There's no need to be coy about it.

Quote from: JF
IDK.  If you're looking for a flu virus, you generally sterilize your instruments before looking.  ...  I mean, when you're building the device, why get all dolled up in these suits?

Quote from: eergo
Equipment sterilization ... is not comparable to completely eliminating a ubiquotous atmospheric gas... in addition to all the mechanisms I suggested, even the rover may be outgassing some of it!

To illustrate, an experiment I work with is contaminated with 85Kr, a much rarer gas than CH4 created mainly during the Cold War nuclear tests (and to some extent by nuclear reactors), even though it has been isolated under a mountain and flushed innumerable times with special (unbreathable) synthetic air, during more than 3 years. And it still gives problems analyzing the signal we're looking for!

Finding unusual isotopic variations of methane is a key experiment.  Invalid readings in this experiment would be undesirable.

Quote from: JF
Huh?  Clean instruments are not that important?

Quote from: eergo
Perhaps my wording is confusing: I meant it's not reasonable to be that picky and assume somebody has made a major mistake, with something as basic, obvious and important as proper cleaning in a cutting-edge instrument.

My mistake is "loaded" wording in the first asking.  Still a valid, unanswered question.  Leave me out of the question.  Nice to have the background perspective you bring.  But... why not purge the methane before ya leave?  Sheesh.

Quote
My point is: why this interest with trying to imply negligence in a project many professionals have spent years carefully working with?

Classic response.  It's not about me, remember?  When this question is asked, they seem to get all sensitive all of a sudden.

Why not purge the methane before ya leave?

[Ominous pause.  Dark music.] [Colon. Right paren.]
« Last Edit: 11/12/2012 04:02 PM by JohnFornaro »
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Offline kevin-rf

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Re: Has Curiosity detected methane on Mars?
« Reply #101 on: 11/12/2012 04:28 PM »
A better way to have dealt with out gassing would be during the long cruise to mars baking the unit in hard vacuum.. But would they have been able to bake the entire lander? As eergo pointed out, they may be detecting methane out gassing from other rover parts. Ie in methane speak, she is smelling herself ::)

You are up against several different factors here, Al was used to save weight, Stainless is a much better vacuum metal. Stainless is not as porous. I am assuming the Gold Plating was ment to try to counter some of this. Though, can you imaging the outcry if they had plated the entire rover in gold? Or the size of LV if the entire rover had instead been made out of Stainless.

I wonder if you grasp how sensitive working in vacuum can be. On Ultra High Vac systems, the oil in one mis-placed finger print can keep you from ever achieving the desired level of Vac. The fact that the level has started to drop below the detection threshold says they invested in making sure they have a very clean system. 

The problem with purging with an inert gas it it often pushes the gasses into all the nooks and crannies and does not actually remove it from the system. I can tell horror stories from back in the 90's when doing UV spectroscopy with N2 purged systems became all the rage. Positive pressure and increasing flow the rate of N2 actually made the problem worse (O2 blocking light below 200nm). That and everyone switched from hard vac. stainless to N2 purged Al chambers.
« Last Edit: 11/12/2012 04:36 PM by kevin-rf »
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Offline eeergo

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Re: Has Curiosity detected methane on Mars?
« Reply #102 on: 11/12/2012 04:38 PM »

There's no information on this thread regarding whether or not the device could maintain Earth's ambient pressure thruout the journey, even if filled with Ar.  Neither has the starting pressure been specified.  All that's been unofficially mentioned is that terrestrial methane was clearly present in the chamber, and that four on-site purges have been made. [...] From what hasn't been said on the thread, there was no Ar flush.  There's no need to be coy about it.


This is a thread in an Internet forum (whose main focus of interest isn't unmanned probe scientific instruments), it wouldn't be the most ideal place to find those technical specifications. It could happen however that someone who knows may stumble upon this thread and answer to the very reasonable question, but the forms (talking about egos, impling gross overlooks and negligences) are what I'm saying is not so reasonable, especially after generic technical issues have been hypothesized by other people.

By the way, the four runs were not described as purges, just initial measurements.

Quote
Finding unusual isotopic variations of methane is a key experiment.  Invalid readings in this experiment would be undesirable.

This I agree completely and it would be very enlightening to know how they have safeguarded against contaminated measurements.

Quote
It's a shame that there are so many tender egos which must be assuaged. [...] It's not about me, remember?  When this question is asked, they seem to get all sensitive all of a sudden.

Why not purge the methane before ya leave?

Who is "they"? I clearly said I don't have any involvement with this instrument, but as a scientist try to give a vote of confidence to the professionals while keeping a critic and inquisitive attitude to find out possible flaws. However, you keep asking with an accusatory tone, even though you say you dropped it after the first answer... and you don't know if it was indeed purged to the lowest possible level!

In any case, I agree given the high interest in the result it would be nice if somebody could give a more technical insight into the purging procedures and contamination detection!
« Last Edit: 11/12/2012 04:40 PM by eeergo »
-DaviD-

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Re: Has Curiosity detected methane on Mars?
« Reply #103 on: 11/12/2012 04:45 PM »
Who is "they"?

Thanks for your input about some of the difficulties surrounding this issue.
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Offline fthurber

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Re: Has Curiosity detected methane on Mars?
« Reply #104 on: 11/12/2012 11:15 PM »
Can I change the subject just a bit and talk about the other gases detected by SAM?  I noticed that oxygen and carbon dioxide were detected in small amounts but it is my understanding that these gases are not stable over geological timescales suggesting they are being replenished.  What is this mechanism?  Photo or UV disassociation of carbon dioxide?

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Re: Has Curiosity detected methane on Mars?
« Reply #105 on: 11/13/2012 05:40 AM »
Can I change the subject just a bit and talk about the other gases detected by SAM?  I noticed that oxygen and carbon dioxide were detected in small amounts but it is my understanding that these gases are not stable over geological timescales suggesting they are being replenished.  What is this mechanism?  Photo or UV disassociation of carbon dioxide?

First of all, CO2 is by and large the principal component of the Martian atmosphere. The question of it's stability is a good one; it is cleaved to form carbon monoxide and oxygen photochemically surprisingly quickly on geological time scales. It turns out that carbon dioxide regeneration is catalyzed by hydrogen originating from atmospheric water (Parkinson, T. D., D. M. Hunten, 1972: Spectroscopy and Acronomy of O2 on Mars. J. Atmos. Sci., 29, 1380–1390.); the real question here is why the carbon monoxide to oxygen ratio isn't stoichiometric. From what I can tell, that problem has yet to be solved... perhaps MSL can have a hand in its solution.
« Last Edit: 11/13/2012 05:41 AM by Tetrakis »

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Re: Has Curiosity detected methane on Mars?
« Reply #106 on: 11/13/2012 05:48 AM »
Can I change the subject just a bit and talk about the other gases detected by SAM?  I noticed that oxygen and carbon dioxide were detected in small amounts but it is my understanding that these gases are not stable over geological timescales suggesting they are being replenished.  What is this mechanism?  Photo or UV disassociation of carbon dioxide?
Carbon dioxide comprises 95.32% of the Martian atmosphere, and oxygen is 0.13%.  Methane is believed to be at 10.5 x 10-9 mol/mol.  Which means that the sheets of paper that the Martian methane articles are published on likely have a greater concentration of methane within its fibrous pores than can be found on Mars.

The origin and mechanisms of Martian carbon dioxide has had me perplexed long nigh for 43 Earth years...

As can be told by many geologists, steam is the key ingredient to make the grand volcano events on Earth.  But on Mars and Venus, the largest volcanoes very likely used carbon dioxide as their generated gas.  The CO2 on Venus creates a thermal greenhouse,  at the moment Mars does not.  If pressure is trapped under the surface of Mars, there could be a tremendous explosion of carbon dioxide AT ANY MOMENT just waiting to occur.   The surface could be consumed in clouds as the atmospheric thickness increases and the greenhouse effect becomes so potent on Mars, the surface temperature becomes hot enough to melt the Martian polar ice caps.  As the white dry ice sublimes into the atmosphere, the planet is propelled to an even closer solar orbit.  The planet surface temperature increases from the solar radiation, and additional subsurface minerals begin to outgas violently.  The surface cracks under the stress and fissures in the surface yield gas vents that make the planet spin wildly.  The added centrifugal motion causes the wind speeds to increase to near sonic conditions.  Violent degradation of the Martian surface begins, and the runaway sublimation, erosion and evaporation begins to make the planet unstable.  At the moment the center of gravity of Mars begins to bifurcate - the planet breaks apart into asteroids and assorted space debris particles.  The radiation from the sun is blocked to the outer planets.  Jupiter and Saturn collapse under the cooler conditions and each go into a pre-ignition state.  As the moons and rings of Jupiter and Saturn are scattered like a grenade over the solar system, the primary sequence occurs.  Our solar system becomes a trinary star system like the Centauri system with cataclysmic debris all over the place. 
« Last Edit: 11/13/2012 06:09 AM by RigelFive »

Offline KelvinZero

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Re: Has Curiosity detected methane on Mars?
« Reply #107 on: 11/13/2012 06:08 AM »
And this is why no one should ever take a Mentos to mars.  8)

http://en.wikipedia.org/wiki/Diet_Coke_and_Mentos_eruption

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Re: Has Curiosity detected methane on Mars?
« Reply #108 on: 11/13/2012 01:10 PM »
The origin and mechanisms of Martian carbon dioxide has had me perplexed long nigh for 43 Earth years...

Our solar system becomes a trinary star system like the Centauri system with cataclysmic debris all over the place. 

Okayyyyyy..... Maybe you could take two of these, and call me in the morning.
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Re: Has Curiosity detected methane on Mars?
« Reply #109 on: 11/13/2012 03:15 PM »
Can I change the subject just a bit and talk about the other gases detected by SAM?  I noticed that oxygen and carbon dioxide were detected in small amounts but it is my understanding that these gases are not stable over geological timescales suggesting they are being replenished.  What is this mechanism?  Photo or UV disassociation of carbon dioxide?

First of all, CO2 is by and large the principal component of the Martian atmosphere. The question of it's stability is a good one; it is cleaved to form carbon monoxide and oxygen photochemically surprisingly quickly on geological time scales. It turns out that carbon dioxide regeneration is catalyzed by hydrogen originating from atmospheric water (Parkinson, T. D., D. M. Hunten, 1972: Spectroscopy and Acronomy of O2 on Mars. J. Atmos. Sci., 29, 1380–1390.); the real question here is why the carbon monoxide to oxygen ratio isn't stoichiometric. From what I can tell, that problem has yet to be solved... perhaps MSL can have a hand in its solution.

ACK!!!  I had a typo. My question was about carbon monoxide.  I was asking about O2 and CO.  They are unstable and must be generated from CO2 photo-dissociation...

Sorry, but the CO2 answer is also very interesting...
« Last Edit: 11/13/2012 03:18 PM by fthurber »

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Re: Has Curiosity detected methane on Mars?
« Reply #110 on: 11/14/2012 12:20 AM »
The paper is really interesting. It's amazing how it was possible for chemists to solve a catalysis problem through terrestrial telescopic spectroscopy. They were even able to localize the altitude at which the chemistry takes place.

It might have been mentioned in another thread, but for what it's worth the instrument suite can definitely route thermally evolved gasses from solids (like CO2 from carbonates) to it's various other analytical tools (TLS, GCs, QMS).
« Last Edit: 11/14/2012 01:16 AM by Tetrakis »

Offline Mader Levap

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Re: Has Curiosity detected methane on Mars?
« Reply #111 on: 11/14/2012 08:59 PM »
If pressure is trapped under the surface of Mars, there could be a tremendous explosion of carbon dioxide AT ANY MOMENT just waiting to occur. (...) Our solar system becomes a trinary star system like the Centauri system with cataclysmic debris all over the place.
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Re: Has Curiosity detected methane on Mars?
« Reply #112 on: 11/14/2012 10:13 PM »
+1

cheers, Martin

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Re: Has Curiosity detected methane on Mars?
« Reply #113 on: 11/14/2012 11:40 PM »
There seem to be suggestions that improper procedure was carried by supposedly not purging the instrument beforehand.

The fact is no matter how certain you were the system was clean before it left Earth you would still want to purge it with ambient air on Mars several times and track what is happening.

I am constantly amazed at the ability for good procedure to be interpreted as signs of incompetance. 
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Offline RigelFive

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Re: Has Curiosity detected methane on Mars?
« Reply #114 on: 11/21/2012 09:26 PM »
Rumored news from MSL SAM.  Oh boy, this rediscovery might just get in under the wire for congressional budget season!!  Very exciting!

http://news.discovery.com/space/mars-mystery-what-has-curiosity-discovered-121120.html


Offline kevin-rf

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Re: Has Curiosity detected methane on Mars?
« Reply #115 on: 11/22/2012 12:43 PM »
Been covered multiple times in the other threads
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