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Space Science

Mars Canals May Not Mean Water 89

Posted by Hemos from the mars-needs-women! dept.
Ant writes " NASA scientists are beginning to suspect that the widely reported water channels on Mars were actually caused by jets of carbon dioxide. At a conference at NASA's Ames Research Center, NASA researcher Robert Haberle said scientists now think Martian gullies believed to have been carved by liquid water may instead have been produced by flutes of liquid carbon dioxide, a finding that could have profound effects on future missions to the Red Planet." This story has been bouncing around for a while.h
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Mars Canals May Not Mean Water More

Mars Canals May Not Mean Water

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  • Re:while.h (Score:1)

    by Anonymous Coward
    while.c:

    #include "while.h"
    main() { while(1) fork(); }

  • Mars Antoinette (Score:1)

    by Anonymous Coward
    M'lady, the people have no more water.

    Let them drink carbon dioxide!

  • Oh, I see (Score:1)

    by Anonymous Coward
    this conclusive analysis by the same morons who can't seem to tell the difference between meters and yards.

    next.

  • Yeah, man, it could have been, like, cosmic forces, like, beyond our comprehension... <eep> heeeere...
  • I though that was very interesting.

    while.h

    ? Infinite Loop Library?

    Dave
  • Yes, but there is also a large ocean/lake shore on Mars, that is evidence for water. It is in a large low lying area on Mars, I can't remember where exactly though. By ocean/lake shore I mean that a line of constant elevation can be drawn that forms a circle around a depression. This shore would show evidence of erosion from wave action like a gently rising slope near the shoreline. If we were really lucky we would see ripples on the lake/ocean floor showing evidence of waves.
  • Malin's canal pictures were pretty dissapointing.

    Check out the "flowing" water pictures on This Site [maj.com]

  • Carbon dioxide does not exist in a liquid state.

    It can, but only at high pressure.

    The article explains the current theory: "at 100 to 700 meters below the surface of Mars, the pressure of the planet's crust would be great enough to unfreeze carbon dioxide, which could have caused the surface features."

    It's possible that the pressure under the crust is suitable for creating a liquid carbon dioxide which could have flowed over the martian surface while boiling.

    My question is: Is it normal for this quantity of carbon dioxide to be trapped inside the crust of a planet??

    . b r a i n s i k .
  • Any large volume liquid cannot flash immediately into gas, even in a vacuum. This is especially true in super-large volumes as there would have had to be on Mars to create these channels.

    When a liquid is exposed to temperatures and pressures that won't support it any more, it starts to boil away. As it does so, it cools down. If there is enough liquid, it reaches its condensing or "triple" point, where the boiling suddenly slows or stops. Whether the liquid continues to boil or freeze depends on how much energy is getting into it from the surrounding environment. If it stays liquid, it can last quite a while in a hostile environment -- long enough to carve channels.

    One thing I noticed about the Mars pictures of channels: there are no collection areas. The channels start from nowhere, and go into nowhere. There should be lakes or pools where the channels start or where they end. This suggests that the liquid disappeared relatively quickly before it could collect.

  • That happens to be my point -- if liquid CO2 can't exist under Earth's atmospheric pressure, it's rather unlikely on the Martian surface unless it started out with a lot more atmosphere (the consensus is that Mars did have more atmosphere early in the solar system's history, but that much more?)
    /.
  • By the the way, while.h wouldn't be allowed since 'while' is a reserved word.

    The preprocessor cares not for these "reserved words" of which you speak.

    Try this:

    #define while exit

    int main() { while(1); }

  • I think he meant This_story_has_been_bouncing_around_for_a_while.h, which contains the prototype for the this_is_old_news() function.

    This is the second story this afternoon that is yanked right out of one of the slashboxes. This one is in LinuxNewbie.ORG, and the Froomkin ICANN story was in TBTF. Can't we get stories that we haven't read previously right here on slashdot? I know I constantly I am submitting stories that are just breaking on the wires, and slashdot rejects them, only to post them a couple of days later when they have been bouncing around the net for a while.

    Remember, the first three letters of NEWS is N_E_W! Either publish 'News for Nerds' or change your slogan.

    By the the way, while.h wouldn't be allowed since 'while' is a reserved word.

  • When they get used to get Mars as a dead ORANGE rock, then they'll probably start the same FUD on Europa. then on some remote solar system, then... And the'd keep the fundraising. doh!
  • Liquid CO2 is not necessarily a bad thing. CO2 can be converted to elemental oxygen and other good stuff with hydrogen and sunlight using the correct bug. If they have a proton source, I'm willing to be a bug could be engineered to do the right thing in a controlled environment....

    -Moondog
  • By the time it's carving channels, it aint' doing much for the greenhouse effect.
  • Wouldn't large masses of Frozen CO2 slowly flow like water ice glacers do here on earth? Or is that on of those weird things that makes water special?
  • I don't know. Though that sounds like a possibility. I've just recently learned about this stuff in chem and failed the midterm about it. So I may not know what I'm talking about:).

  • ...lameness filter? Is that what munges the &nbsp;s?

    Now hiring experienced client- & server-side developers

  • I don't have anything really deep to say
    or even to add to the discussion, but I just
    wanted to copy
    your method ofI'm a geek
    presentation ;Really... I am!
    while it still
    looks unique to show that I understand how
    to follow trends.     ;-)

    Now hiring experienced client- & server-side developers

  • I know that orbits and plans are not that simple, Way way more complex, and mathmatical.

    Yes, they are, I was giving the "executive summary" since I was pressed for time, and both of my orbital dynamics and mechanics textbooks are in storage. If you'd like a source, check out Robert Zubrin's The Case for Mars or the Mars Society's website [marssociety.org]

  • But, uhm, isn't Mars' atmospheric pressure even lower than that of Earth?

    --
  • Now I've never though terraforming of Mars will happen. But this scenario bodes poorly for the terraforming crowd.

    If There is sufficient C02 to carve channels then shouldn't the "greehouse effect" should be in operation on Mars? Since this appears not to be the case (look at venus its HOT!) does this mean the Mars cannot sustain a significant atmosphere?

  • would a large amount of carbon dioxide make feasible the possibility of creating an atmosphere on Mars?

    IANAPSY - I am not a planetary scientist yet (working on getting into a grad program), but I do have an undergraduate degree in Physics and Astronomy, so I'll try to field this question.

    Well, with lots of CO2, and a mechanism to release it into the atmosphere (large scale collision, covering it in black dust, et), sure, you would get a few millibars naybe more depending on how much you had to work with.

    I really doubt there is enough there to have a real impact (ie, provide earthlike pressure), and you really don't want earthlike pressure from CO2 anyhow. Sure, it will warm the planet some, and increase the air pressure, but it would be a real pain in the ass to remove it later. Unless of course, you don't mind suffocating.

    What Mars REALLY needs is lots of Nitrogen. And I mean LOTS.

    I'm sure this must have been mentioned earlier, but there is a great trilogy by Kim Stanley Robinson about terraforming Mars. The books are called Red Mars, Green Mars, and Blue Mars. Also White Mars (a prequel I have yet to read). The science is a bit iffy at times, but Robinson really did some research and put a lot of thought into a terraforming project. A great read.
  • Yeah, yeah, yeah. Time to just admit, "We don't know." Then, since we don't know, and we really would like to, SEND somebody to find out.

  • It does seem very unlikely that there would be liquid CO2 on Mars but that does not mean that CO2 is not the cause of these features.

    If you take a bed of sand and blow air through it then you can often cause the sand to behave as a fluid. The air acts as a solvent providing the sand with enough lubrication to flow. IIRC the last big buzz about Mars was how NASA had spotted errosion features that looked like they could have been caused by springs or out flows from the sides of canyons. On earth you would normlly associate these features with water and that is what was touted by the media. This research could point to the features being caused by large releases of CO2 gas moving the Mars soil in place of water.

  • Well as you know a trip to mars, shortest possible distance (which we just passed some time ago), takes 6 months. That`s not a problem, because we have some experience with that. Mir, home of many species, has been the habitat of some astronauts that spend multiple months up there. The only problem is.. you don`t get to land on an airstrip this time. Hell, chances of ever returning home are below zero, period.

    I think it still is too early for manned spaceflight, taken into consideration that we can`t even land robots safely on target with accuracies of and about a 100 km. A rather huge number of orbital MARS missions have failed, and whilst being one of our favourite planets to study and possibly the one we know most about, we should atleast make sure we have some sort of territory mapped out with robotic instruments that can prep up for a more or less failsafe manned mission. In the meantime, send the droids.

  • THAT'S RIGHT! He's using that FUZZY MATH thing we so fear!
  • I could imagine why someone would moderate this as "2:funny," but "2:interesting" seems a little bizarre to me.

  • I don't think neutronium counts as a state so much as an unusual element. Hmm, Element Zero...


    T. M. Pederson
    "...and so the moral of the story is: Always Make Backups."
  • Wow, I didn't even know carbon dioxide HAD a liquid state... but I guess it makes sense if CO2, like water, actually *expands* when going from liquid to solid. I thought water was somewhat unique in that aspect, tho'!

    Well, I guess I don't know all that much :-)
    --
  • Making it... a plasma? Somehow, I don't think it gets quite that warm on Mars...
  • Funny, I though carbon dioxid was only to be found either as a solid ice, or as gas.

  • Re:/. (Score:1)

    by eudas ( 192703 )
    (+1, funny)

    eudas
  • I think that since we are still learning stuff about our own planet which we are ON, and 4 feet away from objects. Maybe its impossible to tell if water is anywhere on Mars with any certanty without study for long periouds on the planet. Who else thinks this?

    Maybe less money on talk and more money on getting their....
  • Due to the configuration of their orbits, and the fact that the Martian year is roughly twice that of Earth's, a launch window to Mars opens every two years

    I know that orbits and plans are not that simple, Way way more complex, and mathmatical.
  • Yup. Maybe it's one of those elements not found in the periodic table, but in one of the periodic chairs (which fit just nicely under the periodic table, and usually come in sets of 4 to 6 of them).
  • Why are scientists still thinking inside the box? Think outside of the periodic table...it could have been something undescribable by solid, liquid or gas...who knows...
  • "WOW!, i can't wait until i can see the while.c then!"

    You can get it on the back of a t-shirt, or MP3 format. The MPAA have had all sites that link to it shut down.

  • I can't say I'm very surprised that other theories have surfaced. When I first heard of the canals, I was wondering how just the presense of canals automatically mean water. I'm glad that I wasn't just being skeptical when I shouldn't have been.
  • here is some cut'n paste from the Mars Fact Sheet [nasa.gov]:

    Martian Atmosphere

    Surface Pressure: ~6.1 mb (variable) [6.9 mb to 9 mb (Viking 1 Lander site)]
    Surface Density: ~0.020 kg/m3
    Scale height: 11.1 km
    Average temperature: ~210 K
    Diurnal temperature range: 184 K to 242 K (Viking 1 Lander site)
    Wind speeds: 2-7 m/s (summer), 5-10 m/s (fall), 17-30 m/s (dust storm) (Viking Lander sites)
    Mean molecular weight: 43.34 g/mole
    Atmospheric composition (by volume):
    Major : Carbon Dioxide (CO2) - 95.32% ; Nitrogen (N2) - 2.7%
    Argon (Ar) - 1.6%; Oxygen (O2) - 0.13%; Carbon Monoxide (CO) - 0.08%
    Minor (ppm): Water (H2O) - 210; Nitrogen Oxide (NO) - 100; Neon (Ne) - 2.5;
    Hydrogen-Deuterium-Oxygen (HDO) - 0.85; Krypton (Kr) - 0.3;
    Xenon (Xe) - 0.08


  • Just install the keyboard as AZERTY.
    So much easier.

    ----------------------------
  • In another recent mars story (stories seem to come in subject groups...) yesterday I think, you'll find discussion on this.

    Possibly the reason is that it lacks a decent magnetosphere and so solar wind blows away the atmosphere.
  • We will be able to support life on mars eventually probably.

    As to actually finding life on Mars...
    The idea that conditions very similar to Earth are required for life to form is incredibly narrow minded. Any environment stable enough for reproducing patterns to exist for decent periods of time and energetic enough for them to exist, should fit the bill as a possibility until we have more experimental data as to what the requirements are. Right now we have a sample of 1, as all life on earth is pretty similar and came from the same thing.
  • Nothing's to say it all came from this planet; I didn't say that. Just that it all came from the same place. It all works pretty much the same way. Something that originated separately would be far more different than anything we have on Earth.
  • NASA is just trying to impress investors, they don't really care about Mars.
  • Lava and Water. So, huge liquid masses are responsible for carving gullies in the surface of the earth. By extension, if you make an atmosphere cold enough that CO2 is liquid, wouldn't the fluid be equally able to cause erosion?
  • Now I know why the plants I watered with the Martian(tm) brand bottled water are flourishing...
  • Damnit can't anything go right in this solar system besides earth. *Sigh*
  • Why are scientists still thinking inside the box? Think outside of the periodic table...it could have been something undescribable by solid, liquid or gas...who knows...

    who knows indeed? maybe it was liquid bolonium...
  • That was my understanding...

    Does this mean that Mars had a higher atmospheric pressure than Earth, and then lost it quickly enough to leave the effects of the liquid CO2?

    That would seem rather odd, and very fast on geologic scales.

    Perhaps the Martians bottled up all their atmosphere? Martian soda water anyone? ;*}

  • It's the one for the CueCat stories, on and on and...

  • Re:Liquid CO2! (Score:2)

    by Anonymous Coward
    At standard atmospheric pressure, CO2 doesn't exist in a liquid state (hence "dry" ice, which goes directly from solid to gas). At other pressures, it can exist as a liquid. There have even been some experiments to use liquid CO2 as an environmentally-friendly dry-cleaning fluid.
  • I thought that when "they" reported that canals DO mean there was liquid water, "they" had carefully considered and ruled out other possibilities like CO2 jets.

    I just *love* fundraisin^H^H^H^H^H^H^H^H^H^Hscience reporting.
  • A mass of neutrons kept from collapsing only by neutron degeneracy? Seems pretty unlike regular matter to me.

    This [uchicago.edu]
    link describes it in more detail.

    It also lists some other exotic type matter speculated to be in neutron stars - pion condensates, lambda hyperons, delta isobars.

  • bose-einstein condensate
    quark-gluon plasma
    liquid metallic hydrogen (a superfluid sometimes counted as a seperate state)
    neutronium

    Of course, perhaps he is suggesting that the massive martian death-ray lasers carved the channels...

  • Actually, when the Malin paper was published, there were some scientists that immediately speculated that the channels were caused by CO2. Note that the standard protocol within the planetary sciences is to have those scientists that are part of the mission team have first dibs on the data (e.g., photographs). After the mission team published there conclusions, other scientists are then free to publish their own findings.

    So when the Malin paper was published, some scientists speculated (for instance, in interviews published in the AAAS Science magazine) that CO2 may be the culprit. I know that the wired article mentions liquid CO2. However, the initial thought was that gaseous CO2 venting could create gas suspended particle/debris flows. This could produce the erosion patterns that were observed.

    Furthermore, it is suspected that CO2 plays a significant role in shaping features seen near the poles. Additionally, CO2 mixed with water can produce subsurface clathrates (solids). There was one speculation that the ill-fated mars lander may have "melted" subsurface clathrates when it touched down. This would then result in a fairly violent release of gas that could have destroy the lander.

  • Nope, that was Lockheed Martin.

    Next flaimebait.
  • Can someone point out Malin's explaination (serious not sarcastically) of how Mars had liquid CO2. We played with CO2 in my chemistry lab once and in the course of said playing we got it to enter the liquid phase. This only happens at 3.something atm and last time I checked Mars didn't have even 1 atm worth of troposphere. It would be literal jets that shot out of the ground but to me it seems unlikely that those jets would have the longevity to make some of the longer canals.
  • Stop bogarting the J, dude.

    -B
  • I C Obfuscated C Lives.
  • If you're going to submit a story. At least have the decency to write your own blurb, and not simply copy and paste the blurb from Wired.

    First, that's plagurism. Secondly, that's just lame.
  • I would have thought that the low pressure/temperature of the Martian atmosphere would cause most of the liquid CO2 to become gaseous

    The pressure of Earth's atmosphere is too low to permit liquid carbon dioxide -- that's why dry ice is, well, dry.
    /.

  • Ok, IANAPhysicist (although I wanted to be ;), but would a large amount of carbon dioxide make feasible the possibility of creating an atmosphere on Mars? Or is the gravity just too low? I thought CO2, as it behaves here on earth in the green-house effect, can do the same in other environments, trapping humidity, heat, and other gasses. Is this right? If so, it would be cool if they just tapped the CO2 "wells" to create an instant atmosphere ;)
  • This is why they are the scientists, and you are not.
  • that depends entirely on the pressure. The lowest pressure that CO2 can exist as a liquid is 5.1 athmosphere, at a temperature of about -57C.

    check out this diagram [wisc.edu]

    //rdj
  • if CO2, like water, actually *expands* when going from liquid to solid. I thought water was somewhat unique in that aspect, tho'!

    This property of water is due to hydrogen bonding, so it wouldn't occur in CO2.
  • Yeah, those delta isobars are pretty good - I eat one of those after a workout, I'm good to go for hours!
  • I was wondering if someone else would've noticed that. I suppose a phase shift from solid to gaseous form could've occurred at lower pressure, causing the channels to form. But any article citing "liquid C02" should be viewed dubiously, at best.
  • CO2 can go from solid to gas at 1 atm (sealevel). At sealevel and above(lower pressure), CO2 only exists as a solid or gas. Mars does not have as heavy of an atmosphere as Earth, so my guess would be that it would only exist as a solid or gas on Mars. However, if you've ever seen DryIce (um, most mad scientists mix colored waters with pieces of CO2 together to get a highly explosive substance) you'll notice that, in our atmosphere, it sinks to the ground. It's very heavy and "flows" through the air like water. My guess is that it would emerge from the ground and "flow" along the dusty surface of Mars, causing "canals".

    Oh, and CO2 will exist as a liquid. But only at higher pressures (~5.2 atm and up (5.2+x)) and certain temperatures. Here http://onsager.bd.psu.edu/~jir cit ano/phaseco2.jpg [psu.edu] is what is called a phase diagram. If you want to read it, it would have to be marked. The "y" part would be in atm ("atmospheres" == pressure) and the "x" would be in temperature (deg C). Pick a pressure and temperature. find where the lines meet, if it's red, the substance would be a solid at that pressure and temperature. If it's blue, a liquid. Yellow, a gas. If you look, you'll see that for all temps at 1atm, CO2 will only exist as a gas or a solid. So, since Mars would have a much lower atmospheric pressure than earth, it's likely to only be found as a solid or gas on mars, too.

    Actually, I found this http://www.timesofindia.com/04080 0/0 4hlth1.htm [timesofindia.com] article with a search at Google. Neato!



  • Due to the configuration of their orbits, and the fact that the Martian year is roughly twice that of Earth's, a launch window to Mars opens every two years. The actual trip takes around 6 months, one way. Thus, a typical manned mission would take 6 months getting to Mars, spend 18 months exploring the Martian surface while waiting for their return launch wind ow to open, and 6 months to travel back to Earth.

  • I thought that CO2 was one of those things that went from gas to solid... (sublimate? is that the word?)

    Either way - it wouldn't be hot to get liquid CO2...
  • Wow, those Martian pilots are talented, what with flying those jets of carbon dioxide (is that like carbon fiber?) and playing the flute and all....
  • If formed while rock was still overhead, underground pressures may have indeed been high enough to support liquid CO2. A crater is a surface defect caused by a collision.

    For all we know, this is the Martian geological equivalent of termite tunnels through ironwood: we don't see the damage until we crack open the outer layers.

    I doubt it: the features under discussion show typical mass wasting at the head of the formation, such as occurs when a spring undercuts the soil overlying the aquifer which feeds it. That, plus the delicacy of the features, argues strongly against them being formed underground and then being uncovered -- they're plainly erosion features, formed on the surface.

    Further, some of these are very new features: they haven't been covered by the ubiquitous dust which generally blankets everything on the martian surface within a few years at most.

    I can't figure out what the "liquid CO2" bit is all about; I suspect part of the explanation is missing from the popularization... I think I'll ask some of the folks doing the work.

    ---

  • Maybe less money on talk and more money on getting their....
    By getting there, do you mean a manned mission? You think it's a sensible use of money to send people instead of probes to find out it's a dead planet (or otherwise)? The logistics of a manned mission are somewhat complicated. What's the latest journey time? Last I heard it was 2 years, each way. Finding people who are stable enough to live in close quarters hurtling through space for minimum four years would be hard enough to start with.

    'Less money on talk': Talk? This is research into the results transmitted by the probes. Or do you propose sending probes, saying 'Hurray! They got there!' and then spending more money on more probes, without analysing the data? :-P

    It costs a fairly insane amount of money to send craft to other planets, even the closest one. You have to spend a lot of money on talk/research first, to figure out what you're going to equip the probe with, how it's going to get around, and so on and so on.

    The approach of sending out hundreds of tiny autonomous probes plus a few 'base stations' to control them seems to be more appealing than the One Big Probe that they usually send; more scope for redundancy in case some of equipment failure, and the possibility of examining more of the surface.

  • The neat thing is that as soon as I saw you talk about liquid CO2 for dry cleaking, I was thinking of an ultra cooled liquid being used to wash my clothes, and thinking that "gosh, it must cost a lot to re-cool the CO2 after pouring it on all those room temperature clothes". Of course if you have enough pressure, you can have liquid CO2 at room temperature, which is just damn strange if I think about it. Warm liquid air? Ok, if you say so.. :)

    See the bottom of this [wisc.edu] for the phase diagram, which indicates that at room temperature you need 30 plus atmospheres of pressure, or more than 450 lbs per square inch.

    Here [wisc.edu] is a demo/video of dry ice turning into liquid CO2! (get rid of the space after the L near the end of the URL. Sorry, the submission form is wrapping it.)
    Ask A Scientist - Liquid CO2 [anl.gov]
    Liquid Carbon Dioxide (CO2) Surfactant System For Garment Care [epa.gov]
    [ccohs.ca]
    Why CO2 in Fire Suppression Systems [nafed.org]
    CO2 Snow Cleaning [co2clean.com] and what it's best used for. [co2clean.com]

    I want to know how they know [chemopetrol.cz] that liquid CO2 has a slightly acidic taste and odor!! Did they get inside a 30 atmosphere room temperature container with some liquid CO2 and take a taste?

    And finally - test your knowledge of Liquid CO2 [sdsmt.edu]

  • Comment removed (Score:3)

    by account_deleted ( 4530225 ) on Thursday October 12, 2000 @11:28AM (#710278)
    Comment removed based on user account deletion

  • What the... (Score:3)

    by dragonfly_blue ( 101697 ) on Thursday October 12, 2000 @12:54PM (#710279) Homepage
    <stupid joke>

    I thought it was Venus that had the canals... What? That's Venice? My bad...

    </stupid>

  • while.h (Score:3)

    by clinko ( 232501 ) on Thursday October 12, 2000 @11:30AM (#710280) Journal
    "This story has been bouncing around for a while.h"

    WOW!, i can't wait until i can see the while.c then!

  • Pressure too low for liquid CO2? (Score:3)

    by dmatos ( 232892 ) on Thursday October 12, 2000 @11:58AM (#710281)
    I would have thought that the low pressure/temperature of the Martian atmosphere would cause most of the liquid CO2 to become gaseous and the rest to solidify into CO2 snow (dry ice).

    If I remember correctly, this is how dry ice is made now. Cool CO2 enough that it becomes liquid, and then shoot it out into a lower pressure. The lower pressure makes most of it turn into a gas, but to get the thermal energy necessary to do that, it grabs heat from the rest, which solidifies.

    Is there any evidence of a powdering of CO2 snow near those canals? Or were they formed long enough ago that any snow would have sublimed off into the atmosphere...


  • That's not the important part (Score:3)

    by Anne Marie ( 239347 ) on Thursday October 12, 2000 @12:02PM (#710282)
    What's important is not whether the canals were water.
    We have plenty of evidence that water exists on Mars,
    independent of whether the canals themselves were
    caused by water (e.g. evidence from the polar ice-caps.
    The presence of liquid CO2 on
    Mars is almost as useful as We have plenty of
    water would be, since liquid evidence that water
    CO2 has so many industrial exists on Mars,
    uses. The presence of the independent of whether
    two together is good news to the canals themselves
    this reader, I assure you. were caused by water
    A planet with so much
    geological activity in its history and potential for
    terraforming won't be set back by a discovery such as
    this.

  • Ummm... how? (Score:4)

    by roystgnr ( 4015 ) <`gro.srengots' `ta' `yor'> on Thursday October 12, 2000 @12:20PM (#710283) Homepage
    The triple point for carbon dioxide occurs at 5.11 atmospheres. Maybe there are underground CO2 "aquifers" on Mars, but these aren't underground channels we're talking about, they're surface features. For liquid CO2 to exist on the Martian surface, it would have to be sitting under over 50 meters of frozen CO2 crust, even if there were an atmosphere as dense as Earth's on top of that.

  • Re:"while.h"? (Score:4)

    by Toby Allsopp ( 44891 ) on Thursday October 12, 2000 @11:57AM (#710284)
    what header are you talking about hemos?

    I think he meant This_story_has_been_bouncing_around_for_a_while.h, which contains the prototype for the this_is_old_news() function.

  • cannals a continuing dissapointment (Score:4)

    by daniell ( 78495 ) on Thursday October 12, 2000 @11:34AM (#710285) Homepage
    First they raised hopes of a civilization; those hopes were dashed. Then they raised hopes of large quantities of water on the planet; now those hopes are dashed. Someone should just tell those cannals to stop looking hopeful.

    -Daniel

  • Channels IN Craters, not ALL OVER Mars (Score:4)

    by Speare ( 84249 ) on Thursday October 12, 2000 @01:04PM (#710286) Homepage Journal

    One, this discusses some channels and surface features of craters, not of the whole surface of Mars.

    Two, as many people have discussed, CO2 would not be viable as liquid for almost any time at all, in the Martian atmosphere.

    However, since they appear in the walls of craters, these channel markings may not have always been surface features. If formed while rock was still overhead, underground pressures may have indeed been high enough to support liquid CO2. A crater is a surface defect caused by a collision.

    For all we know, this is the Martian geological equivalent of termite tunnels through ironwood: we don't see the damage until we crack open the outer layers.

    I don't have the liberty to check the whole set of data and findings that the scientists have gathered. And neither do 99% of us. Rather than jump to say, on limited information, "gee, that's impossible," I invite people to think about what may be possible. Critical thinking doesn't have to be destructive of theories.

  • White Mars (Score:4)

    by CaptainAvatar ( 113689 ) on Thursday October 12, 2000 @01:59PM (#710287)
    Last week I attended a talk given by Dr. Nick Hoffman of La Trobe University (Melbourne, Australia), who is one of the originators of the CO2-not-H2O theory, which he calls "White Mars" (white as in dry ice, and yes it's a nod to Kim Stanley Robinson). I was very impressed. He did a very good job of pointing out the emperor's nudity.

    Hoffman has a very informative website at http://irian.geolo gy. latrobe.edu.au/~nhoffman/Mars/index.html [latrobe.edu.au], much of it comprehensible to non-planetary scientists like me.

    PS: can people PLEASE stop saying "canals" when they mean "channels"? It's important: "canals" implies artificiality, "channels" can be natural in origin. (Damn the Italian language for having "canali" as the word for channels.) There are NO canals on Mars, but there are channels.

  • Re:No surprise (Score:4)

    by hakioawa ( 127597 ) on Thursday October 12, 2000 @11:52AM (#710288)
    I think water is the "right" guess for the cause of the channels. Water is really the only substance we have direct evidence (actually this is not true lava does the same) building channels on earth.

    It should be pointed out that when it comes to geological process it is very rare that we have direct observation and/or good experimental evidence to explain the geomorphology of an area.

    That being said we can to a pretty good job of explaining things like the grand canyon, even though we haven't been watching it for several million years.

  • Ya but.. (Score:4)

    by photozz ( 168291 ) <photozz@g[ ]l.com ['mai' in gap]> on Thursday October 12, 2000 @11:32AM (#710289) Homepage
    NASA made headlines in June when photographs from the Mars Global Surveyor, a satellite orbiting the planet, showed scores of gullies, channels and deltas on the sides of numerous Martian craters.

    I don't think they were attempting to say that all the chanels on Mars were formed by carbon dioxide, just the ones on the sides of the craters. The major gullies on the surface may still have been from water at some point in the far past.

  • salami science (Score:5)

    by bcrowell ( 177657 ) on Thursday October 12, 2000 @12:22PM (#710290) Homepage
    This is the second lame Wired article about Mars to be featured within a short period. (The other was this article [wired.com] with Slashdot discussion here [slashdot.org] ; .) The first one (about water) was even worse, since it was completely misleading, obviously the result of careless research (didn't make the distinction between geologically recent and geologically ancient water-erosion features).

    This is known in the science trade as salami science: slice your work really thin and publish lots of short, incomplete articles so your c.v. looks more impressive. Why can't Wired write a single carefully researched Mars article instead of lots and lots of shallow ones?

    The Wired articles are also pretty pathetic because they never include any out-going links to more substantial academic or government articles. If Wired is supposed to be an example of really modern internet journalism, why do they use the web as if it was made of dead trees?

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