Martian spiders explained?

JonClarke · Aug 17, 2006

Scientists now have an answer for the strange dark spots near the south polar ice caps on Mars. As the ice cap warms in spring, jets of carbon dioxide erupt, spraying dark material onto the surface. The discovery was made using the cameras on board NASA’s Odyssey and Mars Global Surveyor spacecraft. They provided detailed images of the fan-shaped dark markings, which are typically 15 to 46 metres (50 to 100 feet) across, and can appear within a week. http://www.universetoday.com/2006/08/16/seasonal-jets-darken-the-surface-of-mars/ <div class="Discussion_UserSignature"> 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 Arthur Clarke </div>

rlb2 · Aug 17, 2006

I don’t know if you remember this or not but I posted several images of some “geyser vents” eruption over two years ago, I’m sure they must have questioned them before that. I think this is somewhere near the southpolar region, I didn't post where the image was taken at, just the number of the image? This was some of my comments on them below. Colorized image of Dark streaks on ridge's and gullies. I call them geyser vents, small mounds with holes in the center. You would be amazed at what else I found going though old images of Surveyors and Odyssey. http://uplink.space.com/showflat.php?Cat=&Board=sciastro&Number=1358&page=18&view=collapsed&sb=5&o=0&fpart=9&vc=1 556600-20160-M11-01809psub. <div class="Discussion_UserSignature"> Ron Bennett </div>

rlb2 · Aug 17, 2006

There are more images at the top provided link. <div class="Discussion_UserSignature"> Ron Bennett </div>

3488 · Aug 17, 2006

The Martian 'spiders' are almost certainly due to quickly subliming Carbon Dioxide ice. I am not surprised by the discovery of CO2 geysers, I have been expecting them all along, the latest finds & the amazing images provided by Rib2 confirm this. I will try & find out the location on Mars of Rib2's images. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

rlb2 · Aug 17, 2006

I will try & find out the location on Mars of Rib2's images. Thanks. Click on image I posted go to properties, which will get you the number you would need to look this up. _________________________________________________ I'll through you one of those if-then statements. If CO2 was under pressure it can be very explosive. Then if this can happen to CO2 on Mars it can happen to H2O. You may need a warm spot for H2O geysers. Note the Space shuttle gets an extra boost in the higher atmosphere out of it's liquid rocket engines because water vapor is more explosive in a thin atmosphere. <div class="Discussion_UserSignature"> Ron Bennett </div>

harmonicaman · Aug 17, 2006

Weren't these streaks the same features that were once called "SEEPS" (pseudo-acronym: Suspected Evidence of Erosion Process Sites), and, for a time, thought to be evidence of underground water-ice melting? I think the melting water idea was mostly championed by the anomalists like Hoagland and company... I'm glad NASA has finally found an acceptable explanation for them; but it does put to rest another tantalizing hope for water.

alexblackwell · Aug 17, 2006

Prieto-Ballesteros et al., in the just-published issue of Astrobiology (Volume 6, Number 4, August 2006), might beg to differ.

rlb2 · Aug 17, 2006

Thanks according to that published paper the images I shown above were closer to the equator, +/- 30 degree latitude, don't know what elevation, so those images I’ve shown may be different circumstances because at that latitude CO2 solid doesn't form to easily so H2O geyser vents, seepage, may still be in the running, it all depend on what the surface temperature is in the winter for CO2 to be a factor. <div class="Discussion_UserSignature"> Ron Bennett </div>

JonClarke · Aug 17, 2006

Hi Alex Good to have you back. Long time no see! Jon <div class="Discussion_UserSignature"> 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 Arthur Clarke </div>

alexblackwell · Aug 17, 2006

Good to have you back. Long time no see! Same to you, Jon

I've been hanging out almost exclusively at Doug Ellison's Unmannedspaceflight.com group. I haven't seen you over there in quite some time.

telfrow · Aug 17, 2006

Welcome back Alex! Good to see you posting here again. <div class="Discussion_UserSignature"> Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild. - Tennyson </div>

yevaud · Aug 17, 2006

Welcome back, Sir. A pleasure to have your company again. <div class="Discussion_UserSignature"> Differential Diagnosis: "I am both amused and annoyed that you think I should be less stubborn than you are." </div>

alexblackwell · Aug 17, 2006

Thanks, everyone. The main reason for my lengthy hiatus is due to the fact that, for me, it's really hard to split time between different forums with the frequency of posting that I exhibit, especially when these forums often have different members, posting mechanisms, rules, etc. That said, I do regularly read this group. There are some knowledgable posters here, and I like to hunt for some old posts because, quite often, we've discussed any given topic here in the past ;-)

JonClarke · Aug 17, 2006

yeah, I used to contribute there, but found the anti-ESA mentality that seemed endemic at that time too much aggravation. But I do lurk there still <img src="/images/icons/smile.gif" /> because there is some good stuff there - especially the regular updates on rover progress. As you said in another post, you can't be everywhere at once on the internet, so although i do drop in on some other sites I try and focus on this one (especially since I have aquired some official duties). Best Jon <div class="Discussion_UserSignature"> 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 Arthur Clarke </div>

JonClarke · Aug 17, 2006

Thanks for posting those images again. They do look superficially like the pockmarks I have seen in sonar images of the sea bed from gas seeps. Jon <div class="Discussion_UserSignature"> 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 Arthur Clarke </div>

alexblackwell · Aug 17, 2006

yeah, I used to contribute there, but found the anti-ESA mentality that seemed endemic at that time too much aggravation. But I do lurk there still because there is some good stuff there - especially the regular updates on rover progress. Then you might have noticed that I've posted updates on the upcoming 4th International Conference on Mars Polar Science and Exploration. Some of the abstracts are topical to this thread.

JonClarke · Aug 17, 2006

Thanks Alex! <div class="Discussion_UserSignature"> 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 Arthur Clarke </div>

telfrow · Aug 17, 2006

Nice artist's concept of the jets. From Physorg.com <div class="Discussion_UserSignature"> Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild. - Tennyson </div>

alexblackwell · Aug 17, 2006

Does this mean we should reconsider Nick Hoffman's "White Mars" ideas? Welcome back Alex! Thanks, borman. As for Nick, I haven't conversed with him in quite some time but he should certainly have some interesting insights to these latest results. Having said that, close observers might note that he hasn't published anything (peer-reviewed or not) on his White Mars model in quite some time. I notice he does hang out in the Wild, Wild West (otherwise known as The Habitable Zone) but that's about the extent of my knowledge of his whereabouts or doings. In any event, in my opinion, White Mars hasn't fared very well in the Mars science community, especially in light of the discoveries of the past few years.

paulanderson · Aug 18, 2006

Weren't these streaks the same features that were once called "SEEPS" (pseudo-acronym: Suspected Evidence of Erosion Process Sites), and, for a time, thought to be evidence of underground water-ice melting? I think the melting water idea was mostly championed by the anomalists like Hoagland and company... I'm glad NASA has finally found an acceptable explanation for them; but it does put to rest another tantalizing hope for water. No, it has also been favoured by some other mainstream scientists. I had a good link before to a previous paper, will have to find it again. It has not been put to rest yet... If they are all just dry dust, then why are there newer dark ones often overlaying older, lighter ones (they become much lighter in appearance over time). Note this new "split streak" which diverted around a hill, just posted yesterday on MSSS: http://www.msss.com/mars_images/moc/2006/08/16 Dust or fluid?

JonClarke · Aug 18, 2006

Dry dust flows work very well as explanations for the slope streaks. Where the dust is ligher than the substrate the flow generates a dark streak as the substrate is exposed. they farken over time as more dust is deposited. Light streaks work the same way but occur where the substrate is ligther than the dust. Unlike gullies which are almost certainly the result of water, slope streaks do not have any sign of the geological control necessary for seepage. Jon <div class="Discussion_UserSignature"> 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 Arthur Clarke </div>

3488 · Aug 18, 2006

Could a lot of the slope streaks not be due to a simple warming, cooling cycle, splitting rocks over time, frost forming & causing cracks (frost shattering) which compromise the surface tension, thus causing small rock slides? We know for a fact that Mars over geologic time, or Aerologic time (being Mars), has undergone massive climate changes (like Earth), but could this be evidence of quite sudden short term changes over localized areas? Also could some of these streaks be the results of weak Marsquakes. I think that this subject is far more complicated than any of us realise. Lets hope that the MRO will shed more light on this from October onwards, after reaching the final science orbit. Andrew Brown. <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

exoscientist · Aug 18, 2006

Thanks for that link, Alex. This paper is freely available online. (You may want to download it rather than opening it in a window since it is a rather large file.) I speculated that liquid water might be involved in their formation in a post to sci.astro copied below. The main reason I suggest this is because the dendritic characteristic of the spiders is suggestive of liquid carved channels. Bob Clark ====================================== sci.astro /> CO2-water clathrates to explain the Martian spiders. From: Robert Clark Date: Thurs, Aug 17 2006 9:45 pm Email: "Robert Clark" <rgregorycl...@yahoo.com /> Groups: sci.astro, alt.sci.planetary, sci.geo.geology Greg Orme has a site where he collected several images containing the spiders: Martian Spiders. http://www.martianspiders.com/ The Kieffer et.al. theory of geysering sounds plausible. The only problem I have with it is the dendritic patterns (like a tree branching) seen with the channels that form the "legs" of the spiders. On Earth this has been taken as a signature of channels cut by liquid water. This was part of the reason why the Malin/Edgett gullies were attributed to flowing water. Here's an image showing the spiders with the dendritic patterns: MOC narrow-angle image M11-00280. http://www.msss.com/moc_gallery/m07_m12/images/M11/M1100280.html Robert Bodnar has argued that CO2-water clathrates could be stable at Mars surface conditions and these could have caused the Malin/Edgett gullies. However, he also notes the transition to liquid water brines at higher temperatures would result in explosive gas release: PTX PHASE EQUILIBRIA IN THE H2O-CO2-SALT SYSTEM AT MARS NEAR-SURFA <div class="Discussion_UserSignature"> </div>

JonClarke · Aug 18, 2006

Interesting! Do you have a source to the Schorghofer study? <div class="Discussion_UserSignature"> 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 Arthur Clarke </div>

exoscientist · Aug 19, 2006

yeah, I used to contribute there, but found the anti-ESA mentality that seemed endemic at that time too much aggravation. But I do lurk there still because there is some good stuff there - especially the regular updates on rover progress. Surprising considering that it's moderated by a Brit. - Bob <div class="Discussion_UserSignature"> </div>

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