NASA Briefing: Current Water on Mars?

[MeteorWayne]

I don't think the evidence at the new conference was overwhelming. When we see what's in the full article, and get some follow up observations with different instruments, perhaps it will become more definitive. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[yevaud]

Well, it's rather like in a court of law. There's weak circumstantial evidence and strong circumstantial evidence. Scientists are trained to favor the latter, not the former.<br /><br />Until now, while there have been gullies, outflow channels, pans and so on imaged, none have shown any real evidence of recent activity. So water outflows are (were) only one of a number of possible explanations (Jon can no doubt explain in depth here).<br /><br />But this is very good radiometric data showing what <i>may</i> be recent activity. It's a step forward for certain. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[bonzelite]

<font color="yellow">Too many go way to far with these images....</font><br /><br />including michael malin?! and NASA?! these are the official "dudes" that must withold wild speculations to retain their integrity and reputations. and now they're openly saying it's liquid outflow. <br /><br />a child can look at the rivulets and see that they're made by runoff. in certain cases, yes, you can actually look at something and figure it out.

 

[bonzelite]

the outflow evidence in question is recent. so what do you mean <i>may be</i> recent activity? the timeframe of change here is like 4 or 5 years! this is not recent enough? <br /><br />and this is just what the MGS cameras happened to capture. and the sites that delineate the multiple events are on opposite sides of the planet. so this is activity is not localized. it is planet-wide. <br /><br />the point here is that the martian surface is continually eroded dynamically. it's not only a wholly fossilized snap shot of mars as it was billions of years ago.

 

[yevaud]

4-5 years is plenty recent. Outflows don't occur every day. It may be decades or longer between them.<br /><br />By local, it means local Martian conditions where the outflow occurred.<br /><br />I might add, this is still not proof positive of liquid water flowing. However, it is quite unique in that it is either radiometric evidence of liquid flow, lighter material being exposed, or salts precipitated out from liquid. In any of these three events, liquid flowing - likely H20 - is the prime candidate. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[bonzelite]

recall back some pages ago in one of rib2's threads the exposure of some white and chalky looking regolith that was tilled up in the rover's tracks; i cannot remember which rover it was, but there was lighter, nearly white, material just inches below the rust colored sands. what was this bright material? was it ever determined? <br /><br />whatever it was that exposed this white material carried away the topsoil. and it was a liquid carrier. the gullies terminate in vein-like patterns that denote fluvial activity. i know it's not definitive proof of water, but our choices are narrowed down to that. not much else. unless some highly exotic process is happening with exotic fluids. like absinthe <img src="/images/icons/wink.gif" />

 

[JonClarke]

I guess it's time I jumped in.<br /><br />I haven't had a chance to read the paper yet. Where I work does not subscribe to Science (but I may get it today from a colleague who works in a place which does). But the MSS pages that were linked to above are very informative.<br /><br />There is no doubt that something fluid has flowed down several gullies and deposited bright digitate deposits at Their terminal ends.<br /><br />These deposits are spatially associated only with gullies and are not associated with the previous dark slope steaks which have been seen forming. They are also distinct in morphology and albedo to those streaks are are thus a different to those streaks.<br /><br />The big question is what is the fluidising liquid. I can see three possibilities: <br /><br />1) Grain on grain flow down steep slopes (as happens on the Moon and elsewhere on Mars, forming slope streaks).<br /><br />2) Subliming CO2 resulting in a fluidised flow (again possible examples have been seen elsewhere on Mars).<br /><br />3) A water-mud slurry.<br /><br />Against 1) we have the morphological evidence. These flows look quite diffferent to the dry partice flows we have seen before, especially their digitate distributaries which, as far as I know only form with liquid water.<br /><br />Against 2) we have the fact the mid-latitude occurrence of these features means they are too warm to get CO2 frost or snow.<br /><br />That leaves 3) which is consistent with the detailed morphology of the gullies and flows, and the fact we know that shallow water sources are likelyin many faces on Mars.<br /><br />So where to we go from here? We aren't going to get Steve's drilling rig, nor are we going to get a rover to these sites any time soon.<br /><br />But I am very sure we will have HiRISE images soon, showing the detailed morphology of these features. These will tell us more how the flows behaved and thus what they were composed of. Plus p[eople will be rechecking all the MOC images for any additional e <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[yevaud]

Thank you, Sir. Those were the more detailed references I was searching for (always seek out an expert in the subject field!).<br /><br />And yes, it damned sure is exciting indeed. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[silylene old]

Jon, I get <i>Science</i> with an online subscription. I just emailed the article to you. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[silylene old]

Article is very interesting.<br /><br />Here is the Figure 5 caption:<br /><i>Fig. 5. (Top) Light-toned material deposited in a martian south mid-latitude gully between<br />December 2001 and April 2005. The images shown here were acquired at about the same time of<br />year (E11-03412 at Ls 295.2°; S09-02603 at Ls 276.0°; S10-01184 at Ls 295.0°). Note the digitate<br />apron at the end of the gully in the inset at lower right. The gullies occur in a crater in Terra<br />Sirenum near 36.5°S, 161.8°W; North is up. (Bottom) Light-toned material deposited on<br />southwest wall of a crater in the Centauri Montes region near 38.7°S, 263.3°W. The material was<br />transported through a fine gully channel and the deposit has a digitate terminus. The feature was<br />not present when the crater was first imaged in August 1999. An image obtained in February 2004<br />(R14-02285) showed a portion of the bright deposit, indicating that it had formed sometime<br />between August 1999 and February 2004. North is down and sunlight is from the lower right in<br />these images.</i> <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[silylene old]

Here is Figure 6, with caption: <br /><br />oops forgot the picture.....see next post <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[yevaud]

<i>The material was transported through a fine gully channel and the deposit has a digitate terminus.</i><br /><br />Huh. Like a tiny river delta. Very interesting. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[silylene old]

Figure 6 from the Science article <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[silylene old]

The authors of this article also did a lot of crater size distribution counting, and found and studied several very fresh craters on the Martian surface (some only 40 days to 5 months old), to determine the rates of erosion and loss of dark colored rays in the surface next to the craters. This analysis helped them to date the age of the recent water flows.<br /><br />But, also interesting to me is this quote from the Nature article, in their discussion of their observations of cratering, as it bears on our speculations on the cause of the Martian 'microcraters':<br /><i>For example, the compact<br />distribution of craters in the multiple-crater<br />sites suggests that the breakup occurred relatively<br />close to the surface and with relatively<br />low dispersive energy. The similarity<br />in size of these craters and the general absence<br />of substantive surface disruption between<br />the craters suggests that the meteoroids<br />disaggregated into a small number of similarly<br />sized pieces. Our results appear to confirm<br />models that the smallest craters formed by<br />hypervelocity impact are likely to be a meter<br />or more across (6) and suggest that micrometeoritic<br />impact gardening or breakup of surface<br />materials is a relatively minor component<br />of martian erosion.</i> <br /><br />If you follow their argument, I believe this suggests perhaps that the microcraters we have observed might have been caused by the impact of smaller slower-moving pieces generated by the mid-air breakup of meteorites not that far from the surface. Interesting. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[centsworth_II]

<font color="yellow">"...the microcraters we have observed might have been caused by the impact of smaller slower-moving pieces generated by the mid-air breakup of meteorites not that far from the surface."</font><br /><br />Ah HA! <div class="Discussion_UserSignature"> </div>

 

[bonzelite]

yes, and there is also a greater amount of bright deposting in the larger glob-like bright area of runoff to frame right of the crater wall pics. as if there were more "hardwater stains" accumulated over the past 5 years. <br /><br />because this stuff emerges from crater walls, there must be underground springs running, perhaps, through regions of compacted ice or permafrost. but what is heating or enabling these "veins" or springs to liquefy and travel? and is that what is even happening at all?

 

[gunsandrockets]

"So where to we go from here? We aren't going to get Steve's drilling rig, nor are we going to get a rover to these sites any time soon."<br /><br />It all depends on how you define 'soon'. Over the Thanksgiving Day holiday weekend I talked to someone from JPL about the Mars Science Laboratory rover mission. They have not yet decided where on Mars to send that rover. After this water news, maybe near the Eastern rim of Hellas is now a possibility!<br /><br />"The strong latitudinal control of the gullies in both hemispheres suggests very strongly that it is climate which is controlling their distribution on a global scale, not altitude or regolith."<br /><br />Both hemispheres? I looked on google Mars and I thought both regions were in the Southern hemisphere, and both close to the same latitude and elevation.<br /><br />The locations of the possible water sightings makes perfect sense to me: Southern hemisphere, mid latitude, low altitude. It's probably the region of the planet where temperature and pressure get high enough so that liquid water can exist on the surface, while still close enough to the polar regions so that permafrost isn't too far underneath the surface.<br /><br />If I understand Martian weather correctly, the Southern hemisphere has a colder winter and a hotter summer than the Northern hemisphere. Plus the Southern summer evaporates so much of the South polar ice cap that the atmospheric pressure on Mars increases by 30%! These conditions combine to make the Southern hemisphere the best place to look for liquid surface water.<br /><br />The final factor is the low altitude regions. Some of those areas are so low that atmospheric pressure is much higher than the average pressure on Mars. So much higher that during summer even pure water could exist on the surface, let alone brines.<br /><br />So I say "Send that MSL rover to Hellas!" <br /><br />

 

[gunsandrockets]

"... and suggest that micrometeoritic <br />impact gardening or breakup of surface <br />materials is a relatively minor component <br />of martian erosion." <br /><br />Wow. Very interesting, not only for the implications on Martian geology but also how much less vulnerable manned missions on Mars might be to micrometeoritic impact. Guess that thin Martian atmosphere is good for something after all!<br />

 

[rlb2]

<font color="orange">Our results appear to confirm <br />models that the smallest craters formed by <br />hypervelocity impact are likely to be a meter <br />or more across (6) and suggest that micrometeoritic <br />impact gardening or breakup of surface <br />materials is a relatively minor component <br />of martian erosion.<font color="white"><br /><br />Using your image from above, if it was a hypervelocity impact generated event created by a meteorite then why is more than one apparent seepage event coming from about the same elevation, a layered part of an exposed equal elevation area approximately ½ the distance down from the top of the ridge. The probability of more than one collision of an impacting meteorite happening from that angle at about the same time and elevation would be very low. I’ve seen many springs at equal elevations coming out of a side of mountains, canyons and ridges in the Pacific Northwest while hiking, this is not an unusual event terrestrially. On Mars they would be much more volatile when liquid water first meets the Martian atmosphere, very explosive; possibly creating what may first appear to be a hypervelocity impact from above. <br /><br />After all it took us hundreds of years to figure out that the impact craters on the moon were not mostly of volcanic origin. A subterranean explosion leaves an imprint crater that is not much different than one that is coming from above.<br /><br /></font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[silylene old]

rlb2: I think you misunderstand.<br /><br />The <i>Science</i> paper I quoted from actually covers <i>three</i> significant subjects:<br />1) A refined statistical cratering count calibration<br />2) A refined understanding of the rate of erosion of recent textural features on the Martian surface.<br />3) Compelling evidence of recent water flows in gullies springing from crater rims at certain latitudes.<br /><br />The text I quoted on the meteorites is taken out of context, and is from the portion of the paper which is discussing the methodology of their refinement of the statistical cratering count calibration.<br /><br />The authors never claimed or linked recent meteorite impacts to the formation of springs in crater walls. <br /><br />I apologize for the misunderstanding I may have created by being unclear earlier. I wish I could post the entire <i>Science</i> paper, because I know you would find it fascinating, but that would violate copyright laws. And unfortunately, one cannot read the article unless one pays a subscription fee. Rlb, if you want a copy, pm me with your email and I will send it to you. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[rlb2]

Thanks for that quick update, offer and explanation - this is another reason I need to subscribe to Science. <div class="Discussion_UserSignature"> Ron Bennett </div>

 

[bonzelite]

so you're suggesting some of the recent microcraters with the ejecta, cleary seen in some of the newly released MGS pics, are perhaps from water explosion events. that seems viable. like geysers, but more sporadic than earthly ones.

 

[JonClarke]

Thanks heaps! <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[JonClarke]

I am sure the areaswill be looked at as a possible landing site for MSL, and do appear to fall within the altitude and latitude constraints but it would have to pass several stiff hurdles first. Some issues i can think of:<br /><br />1) Is there a 10 km diameter smooth landing site either inside or outside the craters that MSL can land in?<br /><br />2) Is it possible for the rover to climb down or climb up to the feature (inlcuding the extremely important source area)<br /><br />3) Are there other features in the area worth sending a billion dollar plus mission to if this flow proves to be a dud?<br /><br />Sorry, I wasn't clear when I said that these features are distributed in both hemispheres. What I was trying to say was that gullies occur across the mid latitudes of both hemispheres. The two sites imaged in this paper, as you rightly say, both in the southern hemisphere.<br /><br />The problem with looking for lquid water in the southern hemsiphere is its altiude. Apart from Hellas and Argyre, much of the southern hemisphere is too high for water to be stable. The other hemisphere is much more attractive for this reason, as it is so low. <br /><br />Of course Argyre and Hellas are both very attractive for several regions, and I think there are several sites in reach basin.<br /><br />Jon<br /> <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[bonzelite]

perhaps you meant eastern and western hemisphere (?). the outflow events are on near opposite sides of mars.