The picture on the left is the planet Mars–not as it usually looks (dirty red), but as a false color image to show the presence of something very interesting on the red planet.
Or rather, something very interesting above the surface of the red planet.
The red and yellow patches represent zones of the martian atmosphere in which there is an strong presence of methane.
Why is that significant?
Methane is a compound that is released by life.
And a few other things, such as mud volcanoes. (MUD VOLCANOES! WOO-HOO!)
But there are no known mud volanoes, or active volcanoes of any sort, on Mars.
So that raises the possibility that this stuff is caused by life. Specifically: By underground microbes.
In fact, we see a phenomenon a lot like this on earth. Here on terra firma there are various places where large pockets of underground microbes that produce large plumes of methane in our atmosphere. (Which is one reason why the pluming effect seen above is significant; the stuff isn't even spread throughout the martian atmosphere. Something down on the surface–or below–is generating it.)
In fact, there's one such place not too far up the coast from me in Santa Barbara.
The pattern is also cyclical, with the methane plumes appearing in the martian spring and summer . . . just when the planet is getting warmer and life might be more active . . . and disappearing in the martian fall and winter.
So there are some NASA scientists who are really stoked and talking publicly about this as a possible sign of life.
And it's not the first we've had. In the 1990s there was that meteorite from Mars that showed (debatable) fossils of microorganisms, and back in the 1970s one of the Viking probe tests for life gave a positive result (though other tests didn't).
So . . . who knows? In the photo above you may be looking at the atmospheric signature of life on Mars . . . or not. There are geochemical processes that could produce the same thing.
We'd need to do more tests to know.
I'd love to know the answer on this, but even if there is life, I'd like to know the answer to another question: Where did it come from?
Even if Mars has life, it may not be native to Mars. It may have come from . . . Earth.
As Martian meteorites (there's more than one!) illustrate, matter can pass from one planet to another in the solar system, and here on Earth we have microorganisms that are extremophiles–able to live in very inhospitable environments.
These could be carried to other planets due to impact events that blow chunks of Earth rock into space, or (for all I know) they could be high in the Earth's atmosphere and get carried to other worlds by the solar wind (and Mars is definitely downwind from Earth).
So far as I can tell, we may find extremophile organisms from Earth all over the solar system–living ones where they find a suitable niche and the dead remains of them elsewhere.
So, I've still got questions: (1) Is there really life on Mars? and (2) If there is, where did it come from? Earth? Mars? Or somewhere else?
Thursday NASA had a presser on all this, but they don't have embeddable on-demand video of it on their web site at this point (stupid government agency!) and nobody has yet posted it to YouTube, but
HERE'S A GOOD LIVE-BLOGGING SUMMARY OF IT.
MORE FROM THE HOUSTON CHRONICLE.
Very interesting.
Okay, so the dissociation energy of the first H from methane is about 4.5eV, so a photon with a wavelength of no longer than about 275nm (about the middle of the UV-A range) would suffice. So, assuming this methane pool isn’t changing too quickly, one could estimate the rate methane is produced by finding the intensity of light (generally speaking) at least that energetic at the surface of Mars.
I mean to say it’s about the middle of the UV range (400nm-10nm), at the boundary between UV-B and UV-C (nominally 280nm). UV-C also will kill microbes.
Perhaps more likely than organisms from Earth making their way to Mars is the possibility that the first micro-organisms on Earth in fact came from outer space via a meteorite and that life from this same source somehow made it to Mars as well.
Dear Hans,
What is the solar flux for UV radiation hitting the Martian atmosphere?
Here is a quote from:
ULTRAVIOLET RADIATION ON THE SURFACE OF MARS. D. C. Catling
1, C. S. Cockell 2, and C. P.McKay 1.
1
M/S 245-3, NASA Ames Research Center, Space Science Division/Planetary Systems Branch, Moffett
Field, CA 94035 (catling@humbabe.arc.nasa.gov),
2
M/S 239-20, Exobiology Branch, NASA Ames Research Cen-
ter, Moffett Field, CA 94035
[Quote]
On present day Mars, the total integrated UV flux
over 200-400 nm, is comparable to the Earth’s. How-
ever, on Mars the shorter wavelengths contribute a
much greater proportion of this UV flux. These wave-
length ranges, such as UVC (200-280 nm) and UVB
(280-315nm) are particularly biologically damaging.
Dust, if present, contributes substantially to attenu-
ating the UV flux reaching the surface.
[End quote]
As you point out, if the intensity is high enough to fracture the methane, then there would also, likely, be enough energy to scissor any bacterial proteins, although there is a report that cyanobacterium is able to survive.
Also, if there is methane, but high UV, one would expect to see a higher than normal distribution of hydrogen and methyl radicals that would change in phase with the methane concentration changes.
My guess is that this is geothermal.
The Chicken
I love hanging out here… being surrounded by smart people makes it easier to maintain the illusion that I’m smart myself.
All I know about methane is that it is a major component of cow flatulence, so I’m imagining microscopic cows beneath the surface of Mars, attended by tiny Martian ranchers and probably being protested by tiny environmentalists and Martians For the Ethical Treatment of Microbes.
I have a very high opinion of microbes, myself, especially yeast.
I think the methane comes from hrossa flatulence.
Atleast that’s what the sorns told me.
Given that the Martian soil is primarily composed of andesite-like compounds, such as olivine, there is a possibility that volcanic venting followed by UV reaction with the CO2 in the atmosphere is forming the methane. This was my conclusion and, apparently, < a href="http://www.sciencedaily.com/releases/2005/06/050608052811.htm">some other scientists agree. I think the methane is geochemical. Even so, it would follow a rise and fall with sunlight (UV).
For those who are interested, here is an abstract of a report on the composition of Mars rocks.
[Quote]
The Chemical Composition of Martian Soil and Rocks Returned by the Mobile Alpha Proton X-ray Spectrometer: Preliminary Results from the X-ray Mode
R. Rieder, T. Economou, H. Wänke, * A. Turkevich, J. Crisp, J. Brückner, G. Dreibus, H. Y. McSween Jr.
The alpha proton x-ray spectrometer (APXS) on board the rover of the Mars Pathfinder mission measured the chemical composition of six soils and five rocks at the Ares Vallis landing site. The soil analyses show similarity to those determined by the Viking missions. The analyzed rocks were partially covered by dust but otherwise compositionally similar to each other. They are unexpectedly high in silica and potassium, but low in magnesium compared to martian soils and martian meteorites. The analyzed rocks are similar in composition to terrestrial andesites and close to the mean composition of Earth’s crust. Addition of a mafic [my note: a Mg/Fe composite, richer in Mg – allows volcanic gases to easily escape] component and reaction products of volcanic gases to the local rock material is necessary to explain the soil composition.
[End quote]
The chicken
The link from above.
The Chicken
“especially yeast”
Hear him, hear him! (thumping the table)
I’m not getting too excited just yet. There is frozen methane on dead-as-a-doornail rocks all over space.
Yes there is life on Mars
You may write to me at:
Quarkeston Smith
1 Mars Road
MARS
I will be happy to answer your questions about our cows.
“What is the solar flux for UV radiation hitting the Martian atmosphere?”
Mars is at about 1.5AU, Chicken, so the incident intensity of any part of the solar spectrum will be 1/(1.5^2)=4/9=44.4% of the intensity of the equivalent part of the spectrum incident on the earth. However, the earth’s atmosphere is a much more efficient absorber/reflector of electromagnetic radiation than the thinner Martian (Martial?) atmosphere, and less than 10% of the solar radiation reaches the ground.
“if there is methane”
The point of the story seems to be that there is methane in the Martian atmosphere, surely?
“there is a possibility that volcanic venting followed by UV reaction with the CO2 in the atmosphere is forming the methane.”
My problem with this mechanism is that, so far as I can tell without getting off my duff and going to look properly, the dissociation energy of a CO2 molecule is higher than the dissociation energy for a methane molecule. (I found different values online, but they were all significantly higher for CO2 than for methane.) That means that a larger portion of the solar spectrum would be able to dissociate methane than CO2, so methane would break down faster than the CO2, so to my simple mind it would seem unlikely to accumulate in any significant quantities. (No matter what one’s income is, if he spends faster than he earns, he will never be able to save.)
“I’m not getting too excited just yet. There is frozen methane on dead-as-a-doornail rocks all over space.”
True enough, JohnD, but Mars remains intriguing. It’s in that range where “What if?” is a reasonable question.
All that being said, I’m agnostic as to the source of the Martian methane.
I am, on the other hand, quite fond of certain types of yeast (particularly top-fermenting types) in appropriate circumstances.
The book, Rare Earth, by Peter Ward and Donald Brownlee delves a great deal into extremophiles…I do think that complex life elsewhere out there is pretty uncommon.
“I love hanging out here… being surrounded by smart people makes it easier to maintain the illusion that I’m smart myself.”
I’m not questioning your intelligence, Tim, or anything else, but this quote and the subject matter (and the fact that I pulled the book off the shelf last night) bring to mind this line from the second chapter of book one of Thomas à Kempis’ The Imitation of Christ (Dover edition):
“Indeed a humble rustic who serves God is better than a proud intellectual who neglects his soul to study the course of the stars.”
Hmmm. Scientists have been snapping zillions of pictures of Mars, through a mess of filters, for decades, and suddenly, they find gobs of methane (METHANE for Pete’s sake, not a super rare gas) floating around up there? Something smells funny.
Um…. methane?
We might also note that a humble intellectual is better than a proud rustic who scorns the study of the stars. To borrow a page from St. Paul, if I give up my intellectual life and study, and devote myself to rusticity and and piety, but have not love, I gain nothing.
More helpful, perhaps, might be to see intellectualism and rusticity against the biblical motifs of riches and poverty. With wealth — whether material, intellectual or any other sort — come certain attendant dangers and temptations; with poverty of any sort come certain advantages. But poverty is not good or holy in itself, nor is wealth evil or unholy.
Dear Hans,
I’ll see your quote and raise you two:
From the Star Trek (TOS), The Squire of Gothos:
Trelane: Well, I don’t know if I like your tone. It’s most challenging. That’s what you’re doing, challenging me?
Spock: I object to you. I object to intellect without discipline. I object to power without constructive purpose.
Trelane: Oh, Mr. Spock, you do have one saving grace after all – you’re ill-mannered. The human half of you, no doubt.
From The Outer Limits (Black and White) episode, The Sixth Finger:
Gwyllm: The whole town must be utterly destroyed. An example must be made.
Prof. Mathers: You’re wrong.
Gwyllm: The human race has a gift, professor. A gift that sets it above all the other creatures that abound upon this earth. The gift of thought, reasoning, understanding. The highly developed brain. But the human race has ceased to develop. It struggles for petty comfort and false security. There is no time for thought. Soon there will be no time for reasoning and man will lose sight of the truth.
The operative words in the Imitation quote are humble and prideful. These are conditions of the heart, not states of the intellect, per se.
By the way, the old black and white Outer Limits had, in my opinion, some of the finest writing ever on tv and some of the highest level of language usage. The less said about the 1990 re-make, the better. Here is another really interesting quote from the Old Outer Limits episode, Do Not Open Until Doomsday:
Control Voice: (opening narration) The greatness of evil lies in its awful accuracy. Without that deadly talent for being in the right place at the right time evil must suffer defeat. For unlike its opposite good, evil is allowed no human failings, no miscalculations. Evil must be perfect or depend upon the imperfections of others.
This final quote from the OOL is for its sheer prosody:
Dr. Paul Wayne: So what difference does it make, whether it’s 20 minutes or 20 years, since neither amounts to the faintest echo of the tiniest whisper in the thunder of time.
The Chicken
P. S. I hope I am not breaking any of Da Rulz by my quotes.
In my earlier post, when I said:
Given that the Martian soil is primarily composed of andesite-like compounds, such as olivine, there is a possibility that volcanic venting followed by UV reaction with the CO2 in the atmosphere is forming the methane.
I, naturally, assumed the existence of volcanic H2S, as well. The H-S bond is easier to fracture (81 kcal/mol) than the C=O in CO2 (192 kcal/mol), but the andesite might form a substrate that traps the CO2 and provides greater surface area, so the UV radiation could fracture it. UV radiation at 295 nm is about 97 kcal/mol, which is enough to fracture the HS bond and 200 nm is about 143 kcal/mol, which might be enough to fracture a small fraction of the CO2. To fracture all of it, a wavelength of 148 nm is required (far ultraviolet). The Martian atmosphere blocks UV radiation below 190 nm, but during windy conditions, this might not be the case.
I still think a geochemical explanation is possible, but I would have to do more research to come up with a mechanism beyond my general suggestion and the one cited in the article, above.
The Chicken
Dear SDG and TMC,
I agree. I didn’t say otherwise. Nor did I mean to imply otherwise. Indeed, that seems to be Thomas’ point (or the point of whomever TàK was translating from Dutch into Latin, perhaps); he makes the contrariwise point (that each of you made explicit) later. (And I will repeat, I certainly wasn’t directing the quote at Tim J., whose posts I have always found interesting.)
Ed, methane has been known in the Martian atmosphere at least since Viking in the ’70s. At least my reading is that the point is the localization of the source. (Indeed, of an apparent source.) I’m guessing the smell is methyl mercaptan [(CH3)SH], or something similar.
TMC, my question wasn’t whether the reaction could go forward or not (my chemistry isn’t good enough to make a case one way or another). It was that (assuming that the reaction rates were driven by solar radiation) the reaction rate for breaking apart CO2 wouldn’t be fast enough to keep up with the rate breaking apart methane. I was particularly concerned because all of this is happening in the high-energy tail of the solar spectrum, so the reaction rate would increase faster-than-linearly with decrease in bond strength.
All of that makes sense per molecule (which is the way physicists tend to think, hence I give bond strengths in eV while you give them for the bulk in kcal/mol), and if the numbers of molecules were roughly equal, this effect would dominate. HOWEVER, it occurs to me now [I noticed it before, but it didn’t click] that the density of CO2 in the Martian atmosphere is some 90,000,000 times that of methane, which would make the effective cross-section of CO2 correspondingly higher than that for methane, meaning that the reaction rate for CO2 would be easily more than sufficient to allow methane to accumulate.
So I withdraw my objection.
Dear SDG and TMC,
I agree. I didn’t say otherwise. Nor did I mean to imply otherwise. Indeed, that seems to be Thomas’ point (or the point of whomever TàK was translating from Dutch into Latin, perhaps); he makes the contrariwise point (that each of you made explicit) later. (And I will repeat, I certainly wasn’t directing the quote at Tim J., whose posts I have always found interesting.)
Ed, methane has been known in the Martian atmosphere at least since Viking in the ’70s. At least my reading is that the point is the localization of the source. (Indeed, of an apparent source.) I’m guessing the smell is methyl mercaptan [(CH3)SH], or something similar.
TMC, my question wasn’t whether the reaction could go forward or not (my chemistry isn’t good enough to make a case one way or another). It was that (assuming that the reaction rates were driven by solar radiation) the reaction rate for breaking apart CO2 wouldn’t be fast enough to keep up with the rate breaking apart methane. I was particularly concerned because all of this is happening in the high-energy tail of the solar spectrum, so the reaction rate would increase faster-than-linearly with decrease in bond strength.
All of that makes sense per molecule (which is the way physicists tend to think, hence I give bond strengths in eV while you give them for the bulk in kcal/mol), and if the numbers of molecules were roughly equal, this effect would dominate. HOWEVER, it occurs to me now [I noticed it before, but it didn’t click] that the density of CO2 in the Martian atmosphere is some 90,000,000 times that of methane, which would make the effective cross-section of CO2 correspondingly higher than that for methane, meaning that the reaction rate for CO2 would be easily more than sufficient to allow methane to accumulate.
So I withdraw my objection to the mechanism.
Dear SDG and TMC,
Yes, I’m sorry, I thought that was obvious.
And, as I said, I didn’t intend for it to be seen in any way directed toward Tim, whose comments I’ve always found to be thoughtful and interesting.
Dear Hans
I understood that, for what it’s worth. Chill.
Ah, now they post.
Is this a new discovery? I would have thought they would have checked for methane before now.
Yes indeed it has been done long ago, Jay; it was first done over thirty years ago by Viking.
Raise your hands all of you who sat and watched, seemingly for hours, the first Viking images coming back pixel by pixel, one line at a time. Now [well, as of Dec. 2006] we can take pictures of the Mars rovers [one of them, at least] and the tracks it’s left behind:
http://www.nasa.gov/images/content/163849main_Gusev-d.jpg
(Sorry, too lazy to make a pretty link just now.)
You keep saying that. AFAIK, nobody has suggested that you were directing the quote at Tim J. Were you directing it at someone else?
“Were you directing it at someone else?”
No.
Let’s just say I was having a bad afternoon.
Thanks, Hans. Sorry to press the point, I just wanted to be clear. Hope the rest of your week is better!
(raises hand)
As to Mars, I suppose we have to remember that these papers were written quite some time before they are published, though this recent bit in the news is from 2004.
There certainly is evidence of Martian vulcanism in the past few million e-years, and that on a scale where riverine deposits stated to be 3.5 billion years old are now more likely only a few tens of thousands of years old in the Martian Milankovitch cycle.
Mars is almost certainly not volcanically dead. Even the relatively tiny Moon still has a molten core and occasional surface transients.
Could be bacteria, could be seasonal ice melts working on olivine, could be subsurface volcanic activity.
The image I’ve seen has the plumes over Meridiani Planum and environs, but also looks a bit like gravity waves are involved in the concentrations.