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ToSeek
2004-Mar-02, 03:50 PM
Interesting blog article here (http://mainlymartian.blogs.com/semijournal/2004/03/coming_attracti.html), but read down to the comments for something even more interesting: the possible detection of methane in the Martian atmosphere. If it does exist, it's almost certainly biogenic because no known lifeless processes could create enough of it to be detectable in the Martian environment.

Drakheim
2004-Mar-02, 03:54 PM
Really? No inorganic chemical reactions or volcanism could cause it to be produced?

We know that at one point that there were at least bacteria on that planet... maybe they were (and hopefully are) the culprits.

snabald
2004-Mar-02, 04:03 PM
We know that at one point that there were at least bacteria on that planet...

We do???

ToSeek
2004-Mar-02, 04:09 PM
Really? No inorganic chemical reactions or volcanism could cause it to be produced?



Whatever is creating it has to be ongoing because the Martian radiation environment would break methane down rather quickly.

Drakheim
2004-Mar-02, 04:10 PM
The Martian metro that was found in Antarctica.

snabald
2004-Mar-02, 04:15 PM
The Martian metro that was found in Antarctica.

But hasn't that been disputed as not being proof beyond a doubt?

Squink
2004-Mar-02, 05:17 PM
The Martian metro that was found in Antarctica.

But hasn't that been disputed as not being proof beyond a doubt?
Yes. They found possible tokens for the martian subway, but no certain proof that the transport system ever existed.

skrap1r0n
2004-Mar-02, 06:02 PM
We know that at one point that there were at least bacteria on that planet...

We do???


umm, I haven't heard about this, I know there was a meteor found that had some resemblance to bacterial artifacts/fossils but I never knew it was proven that Mars had Bacteria.

Kaptain K
2004-Mar-02, 06:27 PM
If there is no inorganic means of producing methane, please explain Jupiter!

aurora
2004-Mar-02, 06:32 PM
If there is no inorganic means of producing methane, please explain Jupiter!

I was thinking the same thing when reading this thread. Scary, huh?

:lol:

But someone else pointed out that Methane should break down in the Martian atmosphere. And the Methane in the outer planets probably all formed early when they were still forming.

Interesting. 8)

Amadeus
2004-Mar-02, 06:32 PM
If there is no inorganic means of producing methane, please explain Jupiter!


Jovians like eating beans!

Kaptain K
2004-Mar-02, 06:34 PM
If there is no inorganic means of producing methane, please explain Jupiter!


Jovians like eating beans!
Divine flatulence!? :oops:

ToSeek
2004-Mar-30, 08:18 PM
More about Martian methane (http://mainlymartian.blogs.com/semijournal/2004/03/two_thousand_co.html)

lpetrich
2004-Mar-31, 09:57 AM
Methane could be produced abiotically by certain sorts of chemistry, such as:

CO2 + 4H2 -> CH4 + 2H2O

enabled by various minerals that act as catalysts. This reaction is identical to what methanogens (a kind of microbe) live off of.

However, mineral catalysts vs. biosynthesis processes will likely give different isotopic compositions of the methane, and there aren't any measurements of that. At least not yet.

Other out-of-equilibruium gases to look for:

Hydrogen, H2
Hydrogen sulfide, H2S
Ammonia, NH3

But Martian microbes would have to live in Mars's interior, as some Earth bacteria are known to do; one may have to get a drilling rig to Mars to find them.

BOB2.0
2004-Mar-31, 11:59 PM
It is Martian Bettle Cow Farts I Tell You.....................Futurama anyone?

perigee
2004-Apr-01, 01:25 AM
But Martian microbes would have to live in Mars's interior, as some Earth bacteria are known to do; one may have to get a drilling rig to Mars to find them.

Why would the microbes have to be in the interior? On Earth they must avoid the oxygen-rich atmosphere, but on Mars the CO2 atmosphere should be peachy, particularly as they need CO2 as well. Water is within 1 meter of the surface at high latitudes, and note that the reaction cited above produces water.

Tranquility
2004-Apr-01, 08:28 AM
Question: Is the reaction of hydrogen and carbon dioxide to produce water and methane also the cause of methane on Titan?

JonClarke
2004-Apr-01, 10:49 AM
The methane on Titan is probably primordial. remember that Titan is a lot colder and has a much lower UV flux than mars, and methane is stable. While some is lost to photchemical processes (which is why there is a perpetual smog), the rate is lower. plus the density on Titan is low, suggesting that the crust is largely methane-containing clathrates, so there is probably a steady replenishment of methane.

Jon

Tranquility
2004-Apr-01, 02:41 PM
Thanks gotcha.

Sorry about the following noob question though, I read on Encarta an article that said that Pluto has a very thin atmosphere of methane. Since Pluto's density implies that its a rocky planet, in this case where is the methane coming from? I can imagine Pluto's gravity to be barely strong enough to sustain an atmosphere. And since methane melts at -182.5 C (-296.5 F) and boils at -161.5 C (-258.7 F) shouldnt it be frozen on Pluto?

Dar
2004-Apr-01, 05:57 PM
Ok, vulcanism, tectonic activity, life...all could have something to do with this.
What about the seasonal wax and wane of the polar caps.
Methane could be trapped there and release seasonally.
We may be just discovering whats left frozen in the caps from millions of years ago...it may not be a system of replenishment but a gradual exhaustion of a mass of frozen methane (of course mixed with water, carbon d...etc) on a seasonal bases making it appear to be replenished biochemically.

perigee
2004-Apr-01, 06:14 PM
Freezing point of methane is -182 C. Boiling point is -161 C. Average annual temperature at the poles is -40 C and coldest recorded is -120 C. I.e., no frozen methane reserves at the poles.

Dar
2004-Apr-01, 06:21 PM
Freezing point of methane is -182 C. Boiling point is -161 C. Average annual temperature at the poles is -40 C and coldest recorded is -120 C. I.e., no frozen methane reserves at the poles.

Could it be trapped within something already frozen?
Pockets of methane in frozen water...etc?

As the poles wax and wane these pockets could be exposed?

MKR
2004-Apr-01, 08:28 PM
We know that at one point that there were at least bacteria on that planet...

We do???

Not for sure, but given recent findings, it's hard to deny the possibility.

lpetrich
2004-Apr-02, 06:35 AM
Here's something I'd written for another bboard on this subject:

As to life on Mars, there may be some subsurface life, but I doubt if there is any at the surface. Some liquid solvent is necessary, and water is the most convenient substance. However, liquid water would exist within a very narrow range of temperatures -- when it can exist at all.

Below the surface, however, the pressure will rise, and water will stay liquid over a broader range. The pressure reaches Earth's atmosphere's pressure at about 9 m down (rock column) or 27 m down (water column).

The temperature is more difficult to estimate, but this can be done by extrapolating from the Earth. Which has a very differentiated crust, with the continents being enriched in radioactive heat sources uranium, thorium, and potassium. Mars has a less-differentiated crust, with a composition more like the Earth's mantle and oceanic crust than continental crust. So using the Earth's mantle and applying the square-cube law, the temperature gradient is:

5 K/ km

So to go up to 0 C requires going down 12 km -- with a pressure of 1200 bars. This is only a little more than the pressure at the bottom of the Mariana Trench on Earth (11 km - 1100 bars), and there is plenty of ocean-floor life there.

-

Mars acceleration of gravity: about 3.7 m/s^2, as compared to the Earth's 9.8 m/s^2

The triple point of water is 273.16 K and 6.112 millibars

Mars's average surface pressure is around 7 millibars; the Earth's sea-level pressure is 1013 millibars (1.013 bars).

The Earth's temperature gradient is 15-50 K/km, declaining to about 10 K/km at 35 km down (temperature ~ 350-500 C).

Mars's average surface temperature is -63 C

Square-cube law: volume ~ r^3, area ~ r^2
Heat production ~ mass ~ volume ~ r^3
Heat escape area ~ area ~ r^2
Heat flux is (production)/(area) ~ r
Temperature gradient ~ heat flux ~ r

PeteB
2004-Apr-02, 03:10 PM
Freezing point of methane is -182 C. Boiling point is -161 C. Average annual temperature at the poles is -40 C and coldest recorded is -120 C. I.e., no frozen methane reserves at the poles.


What about a little methane trapped along with CO2 in water ice clathrates?