Sio on November 17, 2009, 09:10:29 am
Four percent?  Ouch.

I hope you realize that at around five percent, methane levels become explosive in an enclosed oxygen environment.  We're not talking the level at which people get a little loopy and see their Roy Rogers' horse Trigger, we're talking the point at which temporally-randomized architectural restructuring can occur.  Or, as Susan Ivanova once described it:

"Boom. Boom boom boom. Boom boom. Boom! Have a nice day!"

Brugle on November 18, 2009, 11:03:51 am
I think that 4% methane is the measured amount in the outside air.

Assuming that about 95% of typical Martian air is carbon dioxide, the compressed outside air with 4% methane, after having "CO2 and other gasses" removed, could be close to half methane.  A fair amount of methane might be added to inside air, but methane could be destroyed by various things (such as the "other treatments" which restore used oxygen).  If the hallucinations are caused by methane, methane destruction is too low to prevent it from accumulating to a significant level.  Alternate possibilities are that there are other gases released (in probably small amounts) when the methane clathrate is heated and that methane reacts (perhaps during the "other treatments") to form other gases (such as methanol).

KBCraig on November 18, 2009, 11:22:49 am

"Boom. Boom boom boom. Boom boom. Boom! Have a nice day!"


Or as Leeloominaï Lekatariba Lamina-Tchaï Ekbat De Sebat (AKA, "Leeloo Dallas") described it:

"Boom. Big. Bada. Boom."
 ;D


JasonAW3 on November 18, 2009, 02:47:14 pm
Well....

    There goes Mexican Food night...

Dang....   :(

GeoModder on November 20, 2009, 01:52:18 am
Mmm... a greener Mars with the release of methane.
A warmer Martian atmosphere I can believe, but to have a greener surface (plants beyond microsize) the air pressure should go up by a few thousand percent of present levels.

quadibloc on November 20, 2009, 04:47:49 am
I presume the idea is that once Mars is made warmer by the methane, which indeed is a more potent greenhouse gas than carbon dioxide (but much shorter-lived in Earth's atmosphere) the permafrost now believed to be under the surface of much of Mars will start to melt and evaporate.

Adding more carbon dioxide and more oxygen, so that plants can grow, would require human intervention, which the release of methane would simply facilitate. Mars is, though, short of nitrogen, and so even to colonize it, without terraforming as an ambition, I could see it as useful to send some comets its way, as comets have ammonia in addition to methane and water ice.

Caelius Spinator on November 20, 2009, 09:07:39 am
The radiative forcing effect of methane on the Mars in EFT is not as easy to quantify as Reg suggests.

Methane is not a particularly good greenhouse gas to the first order. It has no permanent dipole moment like CO2, so its absorption bands are relatively weak. Its importance on the Earth now is due to its relatively low concentration (so its absorption lines are relatively unsaturated) and the locations of absorption lines being relatively unoccupied by other absorbers.

On Mars in EFT, it's presumably going to have these advantages. But the CO2 greenhouse effect is much weaker on Mars, despite having 30-40 x the column mass of CO2 than the Earth. The difference comes from the effect of collisions with other molecules like O2 and N2 which distorts the molecule from its infinitesimally narrow quantum behavior so they can absorb a greater energy range of photons (while conserving their integrated absorption efficiency). Earth has higher pressure, so there are more collisions and broader absorption lines. So, sure 25X CO2 greenhouse effect. But that's much more of a big whoop for Mars than for the Earth.

Of course, there are some other factors:

1. The winter poles in EFT are warmer than present Mars by 40 K. Have the Martians been doing a little terraforming on their own? (That would be a lot of terraforming in fact. The winter pole temperature should be the sublimation temperature of the CO2 cap, which I think is supposed to be still there in EFT (correct me if I'm wrong). If temperatures are 180 K (I think that was the quoted number), the surface pressure at the pole would have to be 300 mb or 100x present). So that's a lot of new pressure, and so Reg is closer to the right ballpark, especially since those lines are more unsaturated than on the Earth (so there's far more bang for your buck).

2. So Mars is different in EFT than today. But what is the methane lifetime? If you think the recent observations that were in the news early this year are correct, it's a few months at most (a few minutes at worst), so its radiative forcing is minimal. It just becomes CO2. I bet higher surface pressure might change how methane is destroyed.

I've loved this storyline...   

SandySandfort on November 20, 2009, 09:11:18 am
I presume the idea is that once Mars is made warmer by the methane, which indeed is a more potent greenhouse gas than carbon dioxide (but much shorter-lived in Earth's atmosphere) the permafrost now believed to be under the surface of much of Mars will start to melt and evaporate.

Exactly.

Adding more carbon dioxide and more oxygen, so that plants can grow, would require human intervention, which the release of methane would simply facilitate. Mars is, though, short of nitrogen, and so even to colonize it, without terraforming as an ambition, I could see it as useful to send some comets its way, as comets have ammonia in addition to methane and water ice.

You don't need to completely terraform Mars to make it more fit for human colonization. A thicker atmosphere may not be breathable, but warm, soft-domed habitats with human-breathable air inside become very easy to construct, even if you have to wear a breathing mask outside on the surface.

GeoModder on November 21, 2009, 04:02:53 am
You don't need to completely terraform Mars to make it more fit for human colonization. A thicker atmosphere may not be breathable, but warm, soft-domed habitats with human-breathable air inside become very easy to construct, even if you have to wear a breathing mask outside on the surface.

Well, if the Tanglenet's creator instanteneous drive works well, there's a way to get huge amounts of nitrogen (and other atmospheric gasses) to Mars in a relatively cheap manner. Place such a "ship" on Titan, fill it up with nitrogen, and sent it to Mars in the blink of an eye. Rinse and repeat.

SandySandfort on November 21, 2009, 10:13:38 am
Well, if the Tanglenet's creator instanteneous drive works well, there's a way to get huge amounts of nitrogen (and other atmospheric gasses) to Mars in a relatively cheap manner. Place such a "ship" on Titan, fill it up with nitrogen, and sent it to Mars in the blink of an eye. Rinse and repeat.

Depends on the parameters within which the drive works. If, for example, the ship could only travel from one place to another place with the same gravitational gradient, that wouldn't work here. Or if the economics of the energy were too costly. The devil is always in the details. Good thinking, though.

quadibloc on November 23, 2009, 07:18:51 am
But what is the methane lifetime? If you think the recent observations that were in the news early this year are correct, it's a few months at most (a few minutes at worst), so its radiative forcing is minimal. It just becomes CO2. I bet higher surface pressure might change how methane is destroyed.

On Earth, in our oxygen atmosphere, methane is unstable for the same reason as, say, hydrogen. It's a fuel; it burns. On Mars, it wouldn't have that problem, so it could be as stable as it is in, say, Jupiter's atmosphere, since carbon dioxide doesn't attack methane any more than ammonia does.

Caelius Spinator on November 23, 2009, 08:47:01 am
In a CO2 atmosphere at present Martian pressures, the electric potential for breakdown is near its minimum. If there is some means of generating static electricity (like collisions between sand/dust in a dust storm), CO2 can lose electrons which can help create species like hydrogen peroxide that can destroy methane.

Here's a link to an ESA summary of a paper on the possibly short lifetime of martian methane
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=45382

Azure Priest on November 23, 2009, 08:53:27 am
I got the "Scotty" quote. Hahahaha!

As for the methane debate, I find it highly fascinating. Although, I'm curious. Where would the Hydrogen for the Hydrogen peroxide come from if the only sources of hydrogen on mars are in the water ice and the methane? I could see the oxygen coming from the CO2, but where would the hydrogen come from?

Brugle on November 23, 2009, 10:49:16 am
CO2 can lose electrons which can help create species like hydrogen peroxide that can destroy methane.

While I wouldn't be surprised to find hydrogen peroxide as an intermediate in a process that destroys methane in the earth's atmosphere, I would be surprised if that occurred in Mars's atmosphere.  I'd guess that whatever complex series of reactions is suggested to create hydrogen peroxide, it would be more likely that those (or similar) reactions would destroy methane more directly.

If the reactions are catalytic on a surface (as apparently considered in the paper you referred to) then the series of reactions might be rather complex, since surface reactions can be very different from those in bulk.

Of course, there are possibilities beyond those considered in that paper.  For example: the paper apparently assumed that the methane levels are in a long-term equilibrium (perhaps with periodic fluxuations), but it could be that methane is released irregularly, with a significant amount released within the past several years.  (Note: I'm not suggesting that that is happening, just that in this case the data is insufficient to have much confidence in any conclusion.)

Caelius Spinator on November 23, 2009, 11:07:14 am
Azure Priest: The water vapor in the air is a good source of hydrogen. 

Brugle: The leading theory in the literature is hydrogen peroxide, but I think you're dead-on in saying the kind of processes that would lead to its production would be a more direct way of destroying methane. And, of course, a longer observational record would be nice.


   

 

anything