New Hope for Mars?

Palomar · 2004-09-23 14:58:27

http://www.spaceref.com/news/viewpr.html?pid=15116]New signs of life found at Earth's Poles

*Short article. Sure tweaks optimism!

"This shows us that places we may think of as extreme - for example other planets like Mars - could nurture surprising habitats for life. The Poles are not the barren wilderness, devoid of life as we previously thought."

--Cindy

Palomar · 2004-09-24 07:57:22

???

Gee whiz...Am I the only person here who finds the above-posted link at least somewhat exciting and arousing of optimism?

Has it been posted previously and discussed in a different thread? I searched for it yesterday, prior to posting. The article is new to the web site as of the date of posting.

--Cindy

Shaun Barrett · 2004-09-24 08:44:46

No, Cindy, you're not the only one and I'm sorry I didn't comment on this article you very kindly linked for us.
I think everyone here knows I believe Mars has a biosphere of some kind. This article is just more evidence supporting an idea which, to me, seems quite logical already. I'm almost afraid to get on my soap box when I see things like this because I imagine people are sick of my lecturing on it!

The mainstream view, still rooted to a large extent in the Viking data, is that there's no unequivocal evidence of life on Mars. I can't argue with this in any definitive way because I have no incontrovertible evidence either!
I have doubts about superoxides in the martian soil and I believe the indications that Mars must have at least microbial life are very compelling.
But until we see macro-fossils in the MER photos or an astronaut digs one up, articles like these probably can't achieve much toward changing the paradigm. I don't need convincing and the mainstream can't be convinced!
Frustrating but true!

Palomar · 2004-09-24 08:58:24

*Hi Shaun. No need to thank me for anything. I'd have been as surprised at the lack of response if someone else had posted it.

Basically I'm very skeptical about life on Mars. This article tweaked some rethinking.

--Cindy

SpaceNut · 2004-10-09 19:33:41

Yup extreme biology on the edge. But did they evolve from organism that were from a more temperate time. If DNA can be used to determine the possible link to a more moderate time in earth history for the polar region and of its temperature.

Julius Caeser · 2004-10-10 11:29:23

The more I read about Mars the more i'm convinced that its a planet that held potential habitats for life to develop but somehow got stalled by the major climate change caused by loss of magnetic field and consequently loss of its atmosphere.At this time that this major change happened ,that is, about 3.8 billion yeras ago,life could not have devekloped further than microbial level,assuming that life would have taken the same time scale to develop as on Earth.From time to time there could have been major water events caused by melting of groundice by volcanic activity or meteoritic impacts but these were temporary phenomena possibly causing the huge floods we still see today in orbital pics!Ofcourse if life ever got a hold on Mars ,i would still think its there somewhere underground or in polar regions.

Shaun Barrett · 2004-10-10 18:05:03

Hi SpaceNut.
Your point is well taken. At the risk of boring you and others who have heard me spout this stuff before, Earth's climatic history is much more varied than most people give it credit for. Technically, we're in an ice-age, which is broadly defined as any period during which a permanent ice cap exists at either pole.
Ice-ages are relatively transient things, in geological time frames. For most of Earth's history, there have been no ice caps at the poles. So, to have one polar cap is relatively rare; to have ice caps at both poles at the same time is even rarer!
They've found the remains of dinosaurs in polar regions which today are frozen barren places, subjected to long dark polar nights. While these finds reflect a degree of physiological diversity and adaptability in dinosaurs we hadn't suspected up until quite recently, that and other evidence tells us Earth's poles were once far less forbidding than they are today.
This brings us to your thoughts on where the present-day extremophile organisms near the poles came from. Your conjecture makes good sense to me. I think it quite likely that such microbes have been there, gradually adapting to the cold, since more clement times.
And I agree that it would be interesting to do DNA analyses to try to determine their origins.

Hi Julius.
I agree with your summary of how life's development, if any, may have progressed on early Mars. There are many unanswered questions, though, as to how long the climate remained amenable to life and how often more benign conditions may have returned, for limited periods, later in the piece. This kind of research is one of my main interests.
But we need to factor in impact transfer of crustal material between the inner planets, too. I believe viable bacteria have been transferred from Earth to Mars, and vice versa, throughout the last 3.5 billion years at least. Such transfer has been added to in recent decades by the arrival on Mars of unsterilised probes from the Soviet Union and incompletely sterilised ones from America and the ESA.
The inner rocky planets are not quarantined from one another.

atomoid · 2004-10-13 01:48:02

Hi SpaceNut.
Your point is well taken. At the risk of boring you and others who have heard me spout this stuff before, Earth's climatic history is much more varied than most people give it credit for. Technically, we're in an ice-age, which is broadly defined as any period during which a permanent ice cap exists at either pole.
Ice-ages are relatively transient things, in geological time frames. For most of Earth's history, there have been no ice caps at the poles. So, to have one polar cap is relatively rare; to have ice caps at both poles at the same time is even rarer!
They've found the remains of dinosaurs in polar regions which today are frozen barren places, subjected to long dark polar nights. While these finds reflect a degree of physiological diversity and adaptability in dinosaurs we hadn't suspected up until quite recently, that and other evidence tells us Earth's poles were once far less forbidding than they are today.

hi shaun,

i had assumed antarctica was warm because it was at a different latitude due either to tectonics continent drift or physical (as opposed to magnetic) pole drift. thats amazing if it was that warm, im probably wrong on that as ive not studied it. paints a new picture of earth for me, as i hadnt considered the poles to ever have been ice-free, i guess that would change weather patters quite a bit without those cold-reservoirs up there, we might end up with a more uniform global temperature if the currents were different in certain ways, kind of like on venus, the heat transport makes the poles and the months-long darkness on the dark side still have similarly hot temperature, when you would think there would be this huge long-lived absolute heat-sink and the winds would be tremendous rushing in to fill that gradient.

Shaun Barrett · 2004-11-25 08:30:16

Hi Atomoid.
Sorry I haven't been back to this thread lately.
There are many factors contributing to Earth's overall climate or average temperature, including the positions of the continents, the extent of volcanism, the amount of tectonic mountain building etc.

The continental plates are constantly shifting; slamming together into supercontinents, then parting company, only to slam together once more.
In doing this, they can assume positions which interfere with global oceanic currents and perhaps disrupt the transfer of heat from equatorial to polar regions. They can even trap an ocean at one of the poles, as is the case today with our Arctic Ocean, which is almost landlocked, or take up position right over a pole, as Antarctica has done. This shifting of land masses not only affects oceanic circulation, but also the movement of warm and cold air masses.
Obviously volcanoes add CO2 and water vapour to the atmosphere, so periods of intense volcanic activity can add greatly to Earth's atmospheric greenhouse effect. There have been suggestions lately that large reservoirs of methane clathrates are stored over geological time in sediments on the sea floor. These reservoirs would be easily disturbed by volcanic and earthquake activity and perhaps suddenly release methane into the atmosphere in great quantities. Methane, as I'm sure you know, is a much more effective greenhouse gas than CO2, which means Earth could have been subjected to sudden 'spikes' in average temperature well above long-term averages.
As continental plates collide and oceanic plates subduct, mountain ranges are pushed up. When this happens, the amount of erosion and 'weathering' of rock increases, which causes CO2 to be sequestered in carbonate rocks. This reduces the greenhouse effect and cools the planet.
The way life responds to the changing conditions is also a factor. When continental positions and other factors created a perfect environment for lush vegetation during the carboniferous period, concentrations of CO2 fell, again producing a marked global cooling.

The present climate on Earth is cold, with the global mean temperature being about 15 deg.C. Without the greenhouse effect of gases like water vapour, methane and CO2, of course, the global mean temperature would be much colder still, at -18 deg.C. So greenhouse gases are a good thing to have!
But for most of the last 600 million years, the average temperature has been well above 17 deg.C, and for about half of that 600 million years it was 22 deg.C.
It's actually very rare for Earth to be as cold as it is now for this long, and quite common for it to be 7 deg.C warmer. A big difference.

When you look at the big picture, you see that a long-term increase in global temperatures is probably to be expected; aside from a few hiccups, the trend is likely to be up. And, as and when that happens, it will only be returning Earth to its customary much warmer conditions.
This is one of the reasons I don't fret too much about the 0.7 deg.C rise in global temperatures purported to have occurred in the last 150 years. Agreed, if it's going to continue and/or accelerate, it will eventually cause problems we'll need to adapt to, so better to play safe with CO2 emissions. But I don't worry too much about a runaway greenhouse effect because, with Earth presently in the grip of a severe ice-age, we've got plenty of leeway before anything that dramatic happens! Plainly, if Earth's climatic balance were that fragile, those much warmer conditions in the past would have turned the place into another Venus a long time ago.

There's a very interesting graph of Earth's average temperature since Pre-Cambrian times at the bottom of http://www.scotese.com/climate.htm]THIS WEB PAGE.

I know this looks a bit off-topic, but I think understanding Earth's substantial climatic variations over geological time spans, even though the planet looks so stable from our limited human vantage point, is good preparation for considering how different Mars may have been in the past. And life hangs on tight once it gets a grip!

Maryjane · 2004-11-25 23:50:32

Hi Shaun interesting thread.
I had always sustpected there was a time before ice, a tropical earth where allot of the water that is today retained in the ice caps was possibly, we'll say, traped water vapor in the ionesphere in the form of ice crystals with the reflectivity of the ice crystals reflecting back sun light to the ground thus adding to the green house effect. For example maybe acumulated ice crystals we'll say from a comet that fell apart around our planet. Maybe the same reminents of the comet that struck the earth and brought the end to the dinasors millions of years before. Suppose if this were so and for some reason all that water vapor in ice crystal form fell towards the tropesphere melting and forming as rain drops, one heck of a flood would ensue I would say, followed by an ice age like the one were still in now as you point out Shaun.

Just a theory

Shaun Barrett · 2004-11-26 01:38:28

There is good evidence that the level of Earth's oceans is normally some 200 metres higher when there is no ice cap at either pole.
In other words, the water currently locked up as polar ice is ordinarily part of the oceans, not part of the ionosphere.

[P.S. A belated welcome to New Mars!]

atomoid · 2004-11-26 19:47:02

Thanks for rescuing this thread with your illuminating entry Shaun,
I have always wondered about that 200 meters of water, not that i seriously doubt it as i have heard something like it quoted widely, but thats really a lot of water to spread around that doesnt seem to be locked up in the poles. From looking at a map one wonders how the relatively 'small' amount of ice could raise the oceans so greatly, especially given that much of the ice in the arctic is floating on water anyway and would have little net effect if it melted or not. thermal expansion couldnt do all that much could it? am i missing something? maybe i just dont have all the facts.

The methane (hydrate?) chlatrates, theres a compeling theory i heard a few years ago that attempts to explain the rapid climate change recorded in teh ice cores by this mechanism, there is so much of this stuff in the seafloor (there are places where chunks of it are now bubbling to the surface) that it can have a huge impact once the sea reaches a couple degrees warmer shifting currents and catastophicly releasing it en masse to the atmopshere and imbalancing climate feedback, as an out of control self-reinforcing problem it takes hudreds of thoudsands of years for natural processes to sequester enough of it (cant remember the process) for the climate to once again cool. the utterly sober article scared the bejesus out of me, as our manmade CO2 insertion would seem to force this tipping point much too soon.

Mad Grad Student · 2004-11-26 20:26:31

Ain't life amazing stuff? No matter how nasty the conditions are, matter always seems eager to find a way to animate itself.

I'm pretty convinced that Mars has an active but limited biosphere today that mostly exists deep underground in hidden aquifers. The cool part is that it's mostly not a matter of belief and hope that life exists, if you look at the evidence everything seems to fit together much more smoothly if Mars is a living planet. At least, that's in my no-degree-in-planetary-science opinion.

Spirit and Opportunity are quite simply the best thing that could have possibly happened for NASA's Mars exploration program. For $400 million apiece they've made the red planet cool again, in a sense that it's never been since the Vikings "proved" that Mars is lifeless. But more importantly, they've practically put the last nails in the coffin of the Wite Mars theory and have given us conclusive, unambiguous evidence that Mars was very wet for a very long time. Even though it's ridiculously complex, at its core life is simply a chemical reaction, and one that will naturally occur on any planet given enough water and enough time. When you factor in ALH84001 it suddenly becomes very difficult to argue that Mars has been completely lifeless ever since it was a protoplanet.

At one time, I believe, life was as prevalent on Mars as it was on Earth (ie, 2 billion years ago?). But Mars just simply isn't as good a piece of real estate as Earth is and it dried out, preventing life from running amok and completely transforming its surface as has happened here. However, we do know of many extremeophiles that could live deep underground and in the icecaps of Mars, practically identical environments to Earth, and Mars Global Surveyor has offered enormous quantities of evidence pointing toward active aquifers on the surface right now. Life was once on Mars and life can currently exist on Mars, it seems logical to venture that life currently exists on Mars if those are both the case.

Now, if only we could go and find it.

RobS · 2004-11-27 22:37:29

Regarding the level of the Earth's oceans, Antarctica is roughly the size of the United States--3 million square miles--and is covered by an average of 10,000 feet of accumulated ice and snow. The oceans occupy 150 million square miles, or 50 times the area of Antarctica. So if all of Antarctica's ice were to melt, the oceans would rise roughly 10,000/50 = 200 feet. Another factor that causes sea level rise is the speed of plate tectonics, because rapid crustal movement is associated with greater heating of the ocean floor near midocean rises. The heated rock expands and displaces water, raising sea level.

When I studied geology 1972-75, we studied the history of transgressions and regressions (when the sea flooded over much of North America, or retreated off much of the continent). Then, we didn't know why these sea level fluctuations happened. Now we do. Too much global warming definitely is bad; it will raise sea level and flood coastal regions, and they are where the bulk of the world's cities are located.

-- RobS

Shaun Barrett · 2004-11-28 19:56:48

Many thanks, Rob, for your input on sea-levels.
Your post caused me to re-think the way I've been interpreting articles on this subject and I've realised I've made an error - an error of degree rather than one of substance, but an error just the same.

I've located http://www.sciencemaster.com/jump/earth … l.php]THIS ARTICLE, which clarifies the situation.

Rob, of course, is perfectly correct in estimating a 200 ft rise in sea-level if the Antarctic ice cap were to melt. This had me confused because I was quite sure I'd been reading of a 200 metre (roughly 600 ft) rise.
The 200 metre rise I'd read about, refers to the total difference in sea-level between that which prevailed in the depths of the last glacial maximum, and that which would prevail if all the ice on Earth were to melt.
The fact is that during the maximum glaciation, sea-levels were some 125 metres lower than they are now.
If all the ice present now were to melt, everywhere on the planet, sea-levels would be some 80 metres higher than they are now.
The difference between the two figures is 205 metres, which explains the figure I've been working with.

I apologise if I've misled anyone as to the numerical effect of climate change on sea-levels due to this misunderstanding on my part.
Thanks again, Rob, for being instrumental in correcting my mistake.

atomoid · 2004-11-29 04:17:45

Thanks to all for helping me get edgemucated!

Since im too lazy tonight to even try to google an answer or start a more appropriate theread for this, does anyone also have any numbers on thermal expansion effects on the oceans?

GraemeSkinner · 2004-11-29 06:04:10

Since im too lazy tonight to even try to google an answer or start a more appropriate theread for this, does anyone also have any numbers on thermal expansion effects on the oceans?

http://sedac.ciesin.columbia.edu/mva/WR … ml]Extract from this page of an article by T.M. L. Wigley & S.C.B. Raper

The relationship between greenhouse-gas forcing, global mean temperature change and sea-level rise due to thermal expansion of the oceans is investigated using upwelling-diffusion and pure diffusion models. The sensitivities of sea-level to short-time scale forcing and deep-water formation rate changes are examined. The greenhouse-gas-induced thermal expansion contribution to sea-level rise between 1880 and 1985 is estimated at 2-5 cm. Projections are made to the year 2025 for different forcing scenarios. For the period 1985-2025 the estimate of greenhouse-gas-induced warming is 0.6-1.0°C. The concomitant oceanic thermal expansion would raise sea level by 4-8 cm.

I had a diagram somewhere of the effect of sea level rise due to thermal expansion but I can't find it, will post it later if it turns up.

Graeme

Palomar · 2004-12-18 15:58:19

http://www.spaceref.com/news/viewpr.htm … 5739]First evidence of microbes living in a rock glacier

Scientists have discovered evidence of microbial activity in a rock glacier high above tree line in the Rocky Mountains, a barren environment previously thought to be devoid of life.
Found in an intermittent stream draining from the glacier, the evidence includes traces of dissolved organic material and high levels of nitrates

Added Williams, "Rock glaciers are not biological deserts as had been previously thought. This is one more example that microbes can live in the most extreme of environments."

*Mentions Antarctica too.

--Cindy

Shaun Barrett · 2004-12-18 17:11:51

Yep, those extremophile bacteria are hardy little critters, that's for sure.
One section of the article which caught my attention with regard to Mars is this one:-

Microbes, which have been shown to metabolize elements like iron, nitrogen and sulfur, appear to require water in order to live, grow and reproduce. Previously at the Niwot Ridge study area, microbes living under the tundra snow pack have been shown to be active in sub-zero conditions, breaking down plant material and metabolizing nitrogen in the dead of winter, Williams said.

Being curious to know what "the dead of winter" might mean in the Colorado Rockies, I checked on Google and discovered the lowest recorded temperature in Colorado was -61 deg.F on February 1st, 1985 at Maybell, elevation 5920 ft.(http://www.usatoday.com/weather/wcstates.htm]This site.)
Translating that, we get -52 deg.C. (It still amazes me that America continues to use the Fahrenheit scale - but that's another story we've covered elsewhere.)

While -52 deg C. is a record low, it at least allows one to guesstimate that "the dead of winter" could easily mean temperatures of -20 to -40 deg.C. (Anyone here who's experienced winter in the high Rocky Mountains might care to correct this, if they think it's inaccurate.)
And again, it's true that while air temperatures might be as low as -30 deg.C, the niches where bacteria are evidently still metabolising may not be quite as cold(?).

However, this whole scenario is definitely in the same ball park, environmentally, as equatorial Mars. And, if memory serves, the average day/night temperature of Mars' northern hemisphere in summer is about -30 deg.C, with daytime maxima as high as +20 deg.C. (Minima being about -80 deg.C)
So, while the lowest night-time temperature in a northern martian summer beats Colorado's record winter low by a good margin, at least any extant martian bacteria get the equivalent of a few hours of Colorado spring weather in the middle of the day!

If terrestrial bacteria can continue metabolising in Colorado under the winter conditions mentioned, it seems very likely to me that any martian bacteria, adapted to much harsher conditions over the eons, could do likewise.
This fits in nicely with the recently discovered methane in the martian atmosphere. Some findings, still to be confirmed and refined, suggest that concentrations of this possible bio-marker gas are greatest in low-lying and equatorial regions of Mars, which is where one might expect the greatest microbial activity because the conditions are more conducive to life.

All very interesting!

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