Earth rocks on Mars

[centsworth_II]

That brings up the question: Have you ever posted an image that wasn't approved, and if so, what was it?<img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> </div>

 

[chew_on_this]

As far as steve goes, I stand by every post (and they speak for themselves) I've made in this thread and have refuted every point he's made hands down. The fact is he won't admit his mistakes even when so glaringly obvious to everyone who reads his posts.

 

[chew_on_this]

I have with one similar to the one I deleted.

 

[centsworth_II]

Mmmm... the Mod rule book must not be clear on this point. Or Leo wasn't fully awake. It's always fun to sail one past the teacher. Although having tried teaching, I sympathise with the teacher. <div class="Discussion_UserSignature"> </div>

 

[chew_on_this]

<font color="yellow">News flash! Life needs water NOW to live, not in the past.</font><br /><br />I've never claimed there is life on Mars NOW.<br /><br /><font color="yellow">No life found on Mars.</font><br /><br />We've looked so hard though haven't we? All I'm out to show is the possibilities.<br /><br /><font color="yellow">But insults and caviling, well, those are your fortes'.Too bad logical, careful, factual reasoning is not.</font><br /><br />If you are the epitome of these characteristics, I'll take that as a compliment. <br /><br /><br />

 

[chew_on_this]

He may not have watched the .gif all the way through. My hair stood on end when I open the thread and saw the big finger. It was kinda funny.

 

[north_star_rising]

Leovinus, the best way I think to answer this question is to send human missions there, and conduct first hand exploration and observation!<br /><br />Everything else is just guesswork and what if?<br /><br />

 

[Leovinus]

Of course there are "best" ways to do something. The best way isn't available to us at present. <div class="Discussion_UserSignature"> </div>

 

[najab]

><i>There is no liquid water...</i><p>There's no large bodies of standing water on the surface - that's all you can say with any certainty. We have seen signs that liquid water has flowed on the surface within very recent geological history, we have seen the signature of significant amounts of water bound up in ices at varying latitudes - some of these ices appear to extend as far as the equator. We know that the surface temperature gets high enough during the Martian summer for water to exist in a liquid state - especially with the salts from the soil mixed in to form a brine. Given those facts, most planetary geologists would agree that your statement is not scientifically accurate.<p>><i>...there is no atmsophere...</i><p>Then what is responsible for the global dust storms, clouds and dust devils?<p>><i>...there are no clearly regenerations of energy sources by which living cells could live and reproduce found...</i><p>What the heck does this mean?</p></p></p></p></p>

 

[chew_on_this]

good, good, you argue with the obstinate one for awhile. At least I see he's changed his tune on the "no life on mars" creedo although it seems he denies he ever held that belief. I guess the delusions continue...

 

[chew_on_this]

Argue with Najab for awhile. I'm sure he'll put you in your place just as handily as I did. Good luck! You'll need it.

 

[najab]

><i>It could be from millions to a hundreds of millions of years ago. It even could be from events which mimic flowing liquids, rather than being water, itself.</i><p>I would put the upper limit on the age of the features we see as hundreds of thousands of years, not tens or hundreds of millions. The main reason for this is because, for the most part, these features cut through craters rather than being cut into by craters. If they were tens to hundreds of millions of years old, one would expect them to have been distorted by impacts, as well as the action of dust transport. It is true that they could be a result of some other fluid flowing, but then the question is: what liquid could that be?<p>The most likely answer - given the conditions we know to exist on Mars, is that they were formed by liquid water. The other candidate - liquid carbon dioxide - requires conditions not likely to be found on the surface.<p>I'm gratified to see that you now seem to acknowlege the fact that Mars has an atmosphere. <img src="/images/icons/smile.gif" /></p></p></p>

 

[najab]

Further to what I wrote in my last post, the other 'problem' with liquid CO2 flows being responsible for the flow features seen in Martian imagery is scale. Some of these features are hundreds, even thousands of metres long (the extreme being huge features like those found in Valles Marineris which are tens of kilometres long).<p>While I can accept liquid CO2 forming short channels when an underground deposit is exposed due to the collapse of the material above, it would take unbelieveably massive amounts of CO2 to form these features, considering that surface conditions on Mars (both pressure and temperature) are <b>well</b> above the sublimation point.<p>If these features were produced by CO2, where did it all go? Why doesn't Mars have a much thicker atmosphere?</p></p>

 

[earthseed]

There may well be "regenerating sources of chemical energy" below the surface of Mars. All it requires is geothermal energy, which may or may not be present in sufficient quantity. On Earth we have bacteria living without any input from the surface, as described in this Scientific American article:<blockquote><em>The bacterial communities living there [in deep basaltic rocks] include so-called autotrophs, organisms that synthesize organic compounds (proteins, fats and other biological molecules rich in carbon) from inorganic sources. Many types of autotrophic bacteria capture energy from inorganic chemical reactions involving iron or sulfur. The autotrophs living in these basalts use hydrogen gas for energy and derive carbon from inorganic carbon dioxide. These "acetogens" then excrete simple organic compounds that other bacteria can in turn consume. In these basalts the hydrogen gas is produced by the reaction of oxygen-poor water with iron-bearing minerals. Many of us call such environments "SLiMEs," for subsurface lithoautotrophic microbial ecosystems. Amazingly, SLiME microorganisms can persist indefinitely without any supply of carbon from the surface.</em></blockquote><br />Getting bacterial to inhabit such an environment on Mars, if one exists, requires a chain of events that may never have happened there. We don't really know what that chain of events is on Earth, never mind Mars. But we do not have enough information yet to conclude what is highly likely or unlikely.

 

[centsworth_II]

<font color="yellow">"...I state repeatedly, clearly and rather decisively, that life on Mars is 'highly unlikely, very unlikely, or exceedingly unlikely' Those are rather exact quotes." -- stevehw33</font><br /><br />Another rather exact quote which you have used so often that I am sick of it, but obviously cannot forget it, is: "There is no life in the solar system outside of the Earth."<br /><br />Perhaps you have relaxed your view. If so, I will relax my opinion of you in relation to that view. <br /><br /> <div class="Discussion_UserSignature"> </div>

 

[centsworth_II]

<font color="yellow">"The problem is that you... cannot see the difference that 'wishing' there is life on Mars, does not logically or scientifically translate into, 'There is probably life on Mars'." -- stevehw33</font><br /><br />While we are getting each other's viewpoint straight, let me set you straight on mine. It is what I consider to be the ONLY responsable, definative viewpoint: "I do not know if there is life on Mars." You can quote me on that.<br /><br />I think Mars is an interesting case study since its past has similarities and differences with Earth's. Are the similarities enough to have allowed life to develop there as it did on Earth? Are the differences enough to have prevented this. Or did life develop on Mars despite the differences? Bottom line: No one knows! But the answer, life or not, will be interesting and valuable to refining theories on life's origins.<br /><br />If I had to bet on whether life, present or past, will be found on Mars, I feel 'no life' is the safer bet. Of course it's a bet I would love to lose -- if the stakes were not too high. If they were high I would not bet.<br /> <div class="Discussion_UserSignature"> </div>

 

[centsworth_II]

<font color="yellow">"We don't really know what that chain of events is on Earth, never mind Mars. But we do not have enough information yet to conclude what is highly likely or unlikely." -- earthseed</font><br /><br />Another of your posts I totally agree with. Now if stevehw33 says he also agrees with it, then perhaps he will have to say that he agrees with me.<img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> </div>

 

[earthseed]

stevehw33 - you are correct in that no evidence of life has been found on Mars, or anywhere else other than Earth. That fact alone is not sufficent to conclude there is no life actually there. You need some information about the planet itself.<br /><br />We can safely agree there is no life on the Moon (not counting life Apollo astronauts brought there). We know enough about it to see the conditions for life are simply not there. Mars is not so simple. From what we know now, we cannot rule out conditions suitable to support life, at least under the surface. We know very little about conditions under the surface.<br /><br />Let me make this clear. Mars may not be able to support life. If it can, there may be no life anyway. As I have said before, we can rule out a thriving ecosystem, because if there was we could detect chemical evidence of their metabolism in the atmosphere, and it is not there. We cannot yet rule out isolated remnants of life.<br /><br />You do not seem to read what people say very carefully. Ironically, both centsworth_II and myself basically agree with your position - life on Mars is unlikely. The difference is you claim certainty when there is insufficient data for that claim, at least on Mars.<br /><br />Not everyone who contemplates the possibility of life on Mars is an "exobiophiliotic". Please read the content carefully before tarring everybody with the same brush.

 

[centsworth_II]

stevehw33:<br />I have hope for you yet.<br />In January, your position was: "There is NO life in the solar system off the earth." (emphasis on "NO" is yours).<br /><br />By March you saw the wisdom of moderation: "...it's exceedingly likely that there is no life in our solar system outside of earth."<br /><br />Now let's see if we can continue your evolution. <br />You repeatedly assume that the surface conditons of a planet, or moon, define conditions within. Mars' surface is cold and dry, with a tenuous atmosphere. Which is precisely why even those who think the chance of finding life on Mars is good do not expect to find it on the surface. Your mistake is assuming that these surface conditions necessarily are repeated at depths beneath the surface. <br /><br />Do you deny any possibility of geothermal heat sources? Of liquid water near such sources? The fact is, we know virtually nothing of Mars' subsurface. What makes you think that you do know? The surface is cold, so 10km beneath the surface is also cold?<br /><br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[centsworth_II]

<font color="yellow">"Really, all the supporters for Martian life have, has been reduced to hypothetical anaerobic microbes, which live off chemosynthesis, at subsurface levels, whose depth is not determined." -- stevehw33</font><br /><br />Searchers for martian life have been reduced to looking in the least likely place to find it, the surface. This is no fault of their's. At worst they could be accused of being premature.<br /><br />As to the "hypothetical anaerobic microbes, which live off chemosynthesis, at subsurface levels". You have described what is possibly the first life form on Earth. Why is it an act of despiration to consider that this same form of life may have arisen elsewhere in the proper conditions (which remain unknown)? <div class="Discussion_UserSignature"> </div>

 

[earthseed]

The key question is geothermal energy. None has been detected by satellite on the surface. But some researchers claim evidence of recent (in geological terms) volcanic activity on Mars. If true, that would mean at least occasional warmth, along with the water we know know is there. Therefore the conditions for life might be present.<br /><br />If so, the actual existence of life under such difficult conditions depends on many other factors. That is why, in my opinion, that life in Mars is possible but unlikely. I give it about 10 percent. <br /><br />If it turns out there is little or no geothermal energy, then the chances of life are about zero, the same as on the Moon.

 

[centsworth_II]

Most intriguing is the presence methane on Mars. Possibly an indicator of sub-surface geothermal processes. Who here can claim to know the source(s) of the methane. Perhaps it comes from solar/surface reactions. But until the methane mystery is solved, that alone leaves the door open to discussion. <div class="Discussion_UserSignature"> </div>

 

[earthseed]

The small amount of methane detected, even in the unlikely event some of it is biological, limits the extent of any life on Mars. A thriving ecosystem would produce a much stronger signal than that.

 

[centsworth_II]

Let me slip into speculation mode. I hope stevehw33 doesn't blow a fuse!<br /><br />Finding rare microbial life, as opposed to a thriving ecosystem, would be sufficient to determine if the organisms were related to Earth life. If so, how closely? If not, how is their biology different? A single bacterium on Earth can tell us a great deal about the biology of all life on Earth. A single cell of Mars life could tell us a lot about a possible alternative biology.<br /><br />Also, could there not be microorganisms on Mars that thrive without releasing methane? The importance of methane in this case would not be direct detection of life, but possible detection of a geothermal energy source that may provide liquid water for non-methane producing Mars organisms.<br /><br />OK, back to the real world. Chance of life on Mars: slim, as far as we know. Source and signifigance of Mars methane: unknown. <div class="Discussion_UserSignature"> </div>

 

[centsworth_II]

<font color="yellow">"I hope stevehw33 doesn't blow a fuse!"</font><br /><br />Oops! looks like he did.<img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> </div>