Mars Water Debate Rages (archival thread reposting #4)

[serak_the_preparer]

voyagerwsh<br />(<b><font color="red">M</font>/b>)<br />02/13/03 11:21 AM<br /><br />Liquid water may have flowed from fragmented river into low depression or lake beds on Mars in the past.<br /><br /><i>“What we found in this study, is that many of these apparently fragmented river features may have connected or flowed into depressions that resemble ancient lake beds,” Kramer explained. "Some of the larger depressions are comparable in size to the Great Lakes in North America in terms of surface area.”</i>--NASA STUDY SHOWS HOW WATER MAY HAVE FLOWED ON ANCIENT MARS</b>

 

[serak_the_preparer]

voyagerwsh<br />(<b><font color="red">M</font>/b>)<br />02/14/03 07:33 PM<br /><br />Dr. James F. Kasting, of Penn State University, believes that Nanedi Vallis, which is half-mile to over a mile wide in places and over a half mile deep and only ~100 feet wide at the bottom, should be carved by liquid water perhaps over millions of years like Grand Canyon.<br /><br />Accordingly, Mars should have a long period of warmer climate and thicker atmosphere, what would contribute the "green house" effect in the distant past? Methane--A biotic contibution by methanogens?<br /><br /><i>"Mars probably did need a biological source of methane to form a planet-warming greenhouse."</i>--James Kasting<br /><br /><br />Early Mars: Warm enough to melt water?, <i>EurekAlert!</i></b>

 

[serak_the_preparer]

cubancat<br />(<b><font color="orange">G</font>/b>)<br />02/14/03 09:02 PM<br /><br />I was looking at how this thread had evolved since the last days that I posted on it in 2002. My interest was piqued by a post from <i>borman</i> dated 12/20/02 10:53 PM that says, among other things:<br /><font color="yellow">”Briefly, a comet hits and regolith mixed with ice is vaporized; rock re-emplants and water rains as much as 2 meters/year for 100 years.”</font><br /><br />So how big of an ice comet would be needed to give Mars 2 meters of water per year (Martian) precipitation rate. Using the Mars Fact Sheet and the formulas for a sphere surface and volume, I attempted to compute the required diameter for a cometary bolide made of water, not accounting for the expansion due to its being ice.<br /><br />With a volumetric mean radius of 3390 km, Mars has an approximate surface area of 144x106 km2. Multiply this by the 2 meters of water per year, results in a value of 288,828 km3 of water for that year period. Since Mars has a sidereal orbital period of 686.980 Earth days, and assuming that the water recycled into the atmosphere every day and was re-precipitated, this decreases the required water volume to approximately 420 km3 of water.<br /><br />Using algebra to rearrange the volume formula, this calculation gives a value for the cometary bolide as <font color="orange">9.295 km</font>in diameter which is within the realm of possibility for a comet nucleus. Thusly, the theory is tenable and quite likely given the visible impact rate on Mars.<br /><br />Al of the Cats<br /><br />"The destr</b>

 

[serak_the_preparer]

borman<br />(<b>A</b>)<br />02/14/03 09:16 PM<br /><br />Possible genesis of Martian Dichotomy and Early atmosphere.<br /><br />Consider the opposite approach from the context of the dirty ice-ball idea, where Mars not only was cold early on but also had no atmosphere. The late accretion phase does not account for the dichotomy between the southern highlands and northern lowlands. There is no justification for the idea that only the lower portion of the planet continued to accrete. Dirty ice should accrete uniformly. Sublimation of the water will leave dirt behind much as glaciers develop a dirty rocky crown. Early on the planetary ice-cap is not anchored to the core. The surface does not neccessarily synchronize with the core. The gasses that will become Mars' atmosphere gets trapped beneath the cap and dissolved in liquid water making a rather large spherical bottle of soda pop. When late accretion commences there is no atmosphere at all to protect the surface facing the sun from the direct solar insolation. The lack of protective atmosphere within the ice-line means the water portion of the dirty ice will be burned off and carried off by the solar wind. An originally uniform Mars will develop a dichotomy if the sun facing side has no atmosphere. Surface dirt upon the ice gets denser due to water loss. As the volcanoes grow up towards and breach the ice, the accumulated gas trapped and dissolved is exposed to very low or no atmosphere and gas bubbles out like from a shaken soda pop can and Mars acquires a thin atmosphere that its gravity can hold on to over a very short period of time. This might bring about a rather large short term flood. The atmosphere will arrest further direct solar erosion stopping the dichotomy from becoming more extreme.

 

[serak_the_preparer]

zentrander<br />(<font color="blue">B</font><br />02/14/03 09:53 PM<br /><br />Just because Mars isn't warm today-doesn't mean we can't terraform it. The whole "polar caps aren't CO2" is overstated, because most of the CO2 is in the regolith, and more powerful greenhouse gases can be synthesized or imported.<br /><br />People scoff at terraforming as a fantasy-but it can, and should happen.<br /><br />People who say we're "playing God"-don't cut down a tree, weed, plant flowers, or mow your lawn! You're terraforming! You evil, evil being! Life terraforms its environment to suit its needs-just because we want to accelerate the process on Mars doesn't make it any different.

 

[serak_the_preparer]

borman<br />(<b>A</b>)<br />02/14/03 10:18 PM<br /><br />Water-world<br /><br />If you find a way to melt the Martian ice mantle, you may have to live in a boat or on a volcano.

 

[serak_the_preparer]

zentrander<br />(<font color="blue">B</font><br />02/14/03 10:35 PM<br /><br />Not really, the water doesn't wash over the planet equally, it settles into the valleys and depressions. Not all of the polar caps have to be metled either-just look at Earth!

 

[serak_the_preparer]

maddad<br />(<b><font color="red">M</font>/b>)<br />02/14/03 11:24 PM<br /><br />Remember that bringing in a comet nearly ten kilometers in diameter also brings in heat. Try calculating the kinetic energy from an object of 420 billion Kg falling from ten billion kilometers away.<br /><br /><br /><font color="orange">Where are we going and what are we doing in this hand-basket?</font>/safety_wrapper></b>

 

[serak_the_preparer]

zentrander<br />(<font color="blue">B</font><br />02/14/03 11:56 PM<br /><br />You don't need to use comets-most heat can be brought in the form of regolith CO2 (which was always regarded as the primary CO2 source), and manufactured greenhouse gases.

 

[serak_the_preparer]

rlb2<br />(<b><font color="yellow">F</font>/b>)<br />02/15/03 03:52 AM<br /><br />Here is something for you to think about. Are there any CO2 (dry ice) comets? All you would need is some comets made out of mostly CO2 to crash into Mars if you can't find enough CO2 on Mars to Terraform it.<br /><br />I read a paper by some prominent scientist over a year ago about how much easier it is to retrieve a asteroid or comet that orbits around the sun as far out as Pluto or more. It uses much less energy to change its orbit. One of the biggest problem is getting out there to retrieve it.<br /><br /><br /><font color="black">Tomorrow begins today and never ends</font>/safety_wrapper></b>

 

[serak_the_preparer]

voyagerwsh<br />(<b><font color="red">M</font>/b>)<br />0/15/03 11:03 PM<br /><br />Borman, one model predicts most Martian channels, vallies, and gullies were formed by groundwater either chaoticaly erupted by geothermal energy or sudden sharp increase in the internal pressure beneath the crust (e,g. major asteroides impacts). Supposedly, under such mode the warmer and thicker Mars atmosphere and climate in the distant past would not be so required or desired. Nevertheless, both models pointed to liquid water is/was the agent to carve or shape those hydrological geo-features.</b>

 

[serak_the_preparer]

zentrander<br />(<font color="blue">B</font><br />02/16/03 05:20 PM<br /><br />http://www.space.com/scienceastronomy/mars_watermap_030216.html

 

[serak_the_preparer]

serak_the_preparer<br />(<b><font color="orange">K</font>/b>)<br />02/18/03 02:21 AM<br /><br />Why has no one posted the following to this thread? Or did I miss something?<br /><br />Mars gets new icing by Philip Ball<br /><br /><i>Shane Byrne and Andrew Ingersoll of the California Institute of Technology in Pasadena have worked out what the martian south pole would look like for various different combinations of frozen water and carbon dioxide. The only arrangement consistent with satellite observations, they find, is a thin layer of dry ice coating a thick cap of water ice....</i><br /><br />Looks like some good news for the Blue Mars camp.</b>

 

[serak_the_preparer]

serak_the_preparer<br />(<b><font color="orange">K</font>/b>)<br />02/18/03 06:09 AM<br /><br />There's also this:<br /><br />Ankle-deep on Mars by Jonathan Amos<br /><br /><i>If the water-ice hidden just below the Martian surface were to melt, it would create a planet-wide sea ankle-deep, scientists have said....<br /><br />"It's become increasingly clear that Mars has enough water to support future human exploration," said Bill Friedman, whose Los Alamos National Laboratory runs the neutron spectrometer on Odyssey....</i><br /><br />And around the poles water constitutes <i>half</i> of the upper soil composition.<br /><br />Wow.<br /><br />That boat might come in handy on the yet-to-be-born Sea of Hellas someday...</b>

 

[serak_the_preparer]

<br />AlexBlackwell<br /><span class="&amp;amp;amp;quot;small&amp;amp;amp;quot;">(<font color="#ccffff"><b>A</b></font>)<br /> 02/18/03 09:09 PM<br /><p class="&amp;amp;quot;post&amp;amp;quot;"><br />For those who do not have online access to Science, the Byrne and Ingersoll paper is available on the Caltech GPS server. Click here. <br /><br /><br />Alex R. Blackwell<br />University of Hawaii</p></span>

 

[serak_the_preparer]

<br />voyagerwsh<br /><span class="&amp;amp;amp;amp;quot;small&amp;amp;amp;amp;quot;">(<font color="#ff0000"><b>M</b></font>)<br /> 02/19/03 03:19 PM<br /><p class="&amp;amp;amp;quot;post&amp;amp;amp;quot;"><br />Proposed by Dr. Philip Christensen, of Arizona State, martian gullies "are created by trickling water from melting snowpacks" argues Christensen as oppose to groundwater seepage which other model has predicted...<br /><br /><i>"I would think life, if it exists on Mars, would migrate toward exactly these environments," Christensen said. "The snow sits there and acts as this wonderful blanket that allows all of this melting and trickling to go on."</i><br /><br />Trickle Down Theory of Melting Snow May Support Life on Mars, Space.com</p></span>

 

[serak_the_preparer]

<br />AlexBlackwell<br /><span class="&amp;amp;amp;amp;quot;small&amp;amp;amp;amp;quot;">(<font color="#ccffff"><b>A</b></font>)<br /> 02/19/03 03:34 PM<br /><p class="&amp;amp;amp;quot;post&amp;amp;amp;quot;"><br />A few relevant links:<br /><br />======================================<br />Nature Advance Online Publication (AOP)<br />Letters to Nature<br />19 February 2003 <br /><br />Formation of recent martian gullies through melting of extensive water-rich snow deposits <br />PHILIP R. CHRISTENSEN<br />doi:10.1038/nature01436<br /><br />First paragraph<br /><br />======================================<br /><br />NASA's Mars Odyssey Points to Melting Snow as Cause of Gullies<br /><br />======================================<br /><br />(THEMIS Press Release, 2/19/03) Snow on Mars<br /><br />Alex R. Blackwell<br />University of Hawaii</p></span>

 

[serak_the_preparer]

voyagerwsh <span class="&amp;amp;amp;amp;amp;quot;small&amp;amp;amp;amp;amp;quot;"><br />(<font color="#ff0000"><b>M</b></font>)<br />02/19/03 05:02 PM <p class="&amp;amp;amp;amp;quot;post&amp;amp;amp;amp;quot;"><br />(Repost) "Networks of channels found on Devon Island bear similarities to the so-called Martian small valley networks. On Mars, most of these features date back to the end of the "Heavy Bombardment" (a period of high impact rates early in the history of the solar system). Some of these features are also found on more recent Martian terrains such as the flanks of relatively young volcanoes.<br /><br />The surface of Devon Island has been carved by a multitude of small valley networks that bear an uncanny resemblance, including in their bizarreness, to the many small valley networks on Mars. Curiously, when you consider the classical explanations for Martian small valley networks, the Devon Island networks formed neither by rainfall, groundwater or ground-ice release, or mud flow. Rather, they were formed by the melting of vast ice covers that once occupied the land above the material exposed at the surface today.<br /><br />Given what we see on Devon Island, is it possible then that the many small valley networks on Mars were actually formed under a frigid climate rather than under a warm and wet one? Might Mars have been cold climatically throughout most its history, with liquid water at most a local and transient phenomenon at the surface?"<br /><br />Mars on Earth<br />--------------------------------------------------<br /><br />Implication of channels networks near Haughton Crater may bear similar formations of Martian gullies in a way, i.e. surface ice melting mechanism. Interesting.<br></br></p></span>

 

[serak_the_preparer]

<br />exoscientist<br /><span class="&amp;amp;amp;amp;quot;small&amp;amp;amp;amp;quot;">(<font color="#66ccff"><b>B</b></font>)<br /> 02/20/03 08:53 AM<br /><p class="&amp;amp;amp;quot;post&amp;amp;amp;quot;"><br /> Thanks for the link.<br />I like the fact that recently when the news media shows pictures of Mars it often shows the "Green Mars" picture taken by Hubble.</p></span>

 

[serak_the_preparer]

<br />exoscientist<br /><span class="&amp;amp;amp;amp;quot;small&amp;amp;amp;amp;quot;">(<font color="#66ccff"><b>B</b></font>)<br /> 02/20/03 09:14 AM<br /><p class="&amp;amp;amp;quot;post&amp;amp;amp;quot;"><br />Thanks for the link to the full paper Alex. I wanted to know if they did temperature modeling to conclude water could be liquid under an insulating snow blanket only a few inches deep.<br />If so then that gives credance to my view that in the near polar latitudes under an ice cover several meters deep you could have briny liquid water lakes:<br /><br />Re: More Water On Mars from ABC and Science<br />Posted by Robert Clark (68.81.141.219) on 2/13/2003 7:50:57 PM<br />In Reply to: More Water On Mars from ABC and Science posted by BD on 2/13/2003 12:46:22 PM<br />http://habitablezone.com/space/messages/30883.html<br /><br /><br />Bob Clark</p></span>

 

[serak_the_preparer]

<br />exoscientist<br /><span class="&amp;amp;amp;amp;quot;small&amp;amp;amp;amp;quot;">(<font color="#66ccff"><b>B</b></font>)<br /> 02/20/03 09:14 AM<br /><p class="&amp;amp;amp;quot;post&amp;amp;amp;quot;"><br /> Ack! Just realized the link is not to the Nature paper on the gullies but to the water at the south pole paper.<br />In any case I'll take a look at the temperature modeling at the south pole.<br /><br /><br />Bob C.</p></span>

 

[serak_the_preparer]

<br />voyagerwsh<br />(<font color="#ff0000"><b>M</b></font>)<br />02/20/03 10:13 AM<br /><br />Supplement paper from abstract in LPSC XXXIII<br /><br />GULLIES ON MARS: CLUES TO THEIR FORMATION TIMESCALE FROM POSSIBLE ANALOGS FROM DEVON ISLAND, NUNAVUT, ARCTIC CANADA. (PDF)

 

[serak_the_preparer]

<br />spaceseed<br />(<font color="#66ccff"><b>B</b></font>)<br />02/20/03 12:04 PM<br /><br />I am wondering where the snow in the Martian craters is meant to have come from? The only hint I can see is from the introduction in Nature:<blockquote><em><br /><br /><i>Here I show that gullies can form by the melting of water-rich snow that has been transported from the poles to mid-latitudes during periods of high obliquity within the past 10⁵ to 10⁶ years.</i></em></blockquote><br /><br />I take it this means that when Mars' axis is tilted, the ice caps melt and the water is transported to lower altitudes, being deposited on sheltered walls of craters. Some more information about this can be found in A topographically forced asymmetry in the martian circulation and climate (this is Google's cached copy that gets around needing a subscription).<br /><br />I really wonder if this mechanism would transport enough snow to produce the observerd quantity of gully formation for so long.

 

[serak_the_preparer]

rlb2<br />(<font color="#ffcc66"><b>G</b></font>)<br />02/21/03 10:39 AM<br /><br />I was at the Mar Society conference in Toronto when they presented this same thing 3 years ago. I remember Pascal Lee showing slides. See picture below.<br /><br />"Note from planetary scientist Pascal Lee with regard to an announcement made yesterday at NASA headquarters regarding a possible origin for gullies observed on Mars"<br /><br />"The spacecraft data discussed by Phil Christensen is new and beautiful, but the interpretation of the martian gullies as resulting from the melting of snow and ice patches in response to obliquity (tilt) variations of Mars on timescales of 100,000 years or so is something my colleagues and I have proposed and published for the past three years."<br /><br />"Our model was proposed on the basis of terrestrial analog field studies we have conducted on Devon Island in the Canadian Arctic under the auspices of the NASA Haughton-Mars Project "(www.marsonearth.org).<br /><br />http://www.spaceref.com/news/viewnews.html?id=754<br /><br /><font color="black">Tomorrow begins today and never ends</font><br /><br />http://images.spaceref.com/news/2002/06.06.02.gullies.jpg

 

[serak_the_preparer]

<br />voyagerwsh<br />(<font color="#ff0000"><b>M</b></font>)<br />02/21/03 05:29 PM<br /><br />Thanks for the link and images, snow melting model is very plausible, RLB2. However, it should need to answer the question--<i>"the relationship to layering, and why two craters of similar size can occur within a few kilometers of each other, yet one has gullies and the other (Bond Crater) does not..."</i>--POLAR- AND MIDDLE-LATITUDE MARTIAN GULLIES: A VIEW FROM MGS MOC AFTER 2 MARS YEARS IN THE MAPPING ORBIT., K. S. Edgett et. al Malin Space Science Systems, Inc., Abstract, LSPC XXXIV.<br />------------------------------------------------------------------------<br /><br />Nevertheless, both models predict liquid water could be the volitile agent to carve martian gullies.<br /><br /><i>"I think it's the most plausible explanation we've had so far,'' he (Michael Carr) said. "But I suspect we're not there yet.''</i><br /><br />Theory suggests snowmelt on Mars might have supported life