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Space Science

NASA Says Mars Once "Drenched With Water" 1048

NASA is currently holding a press conference (carried live on NASA TV) where they are discussing findings from the Mars rovers. They are saying that the crater that the second rover has landed in has convincing evidence that it was once drenched or covered in liquid water. They cite the tiny spherules, odd holes in the rocks, sulfur in the spectrometric analyses, and evidence of an iron sulfate hydrate (a hydrate is a chemical compound which includes water molecules in the crystal lattice). Update: 03/02 19:45 GMT by M : CNN has a story, or see the NASA press release.
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NASA Says Mars Once "Drenched With Water"

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  • Link to the web case (Score:5, Informative)

    by seann ( 307009 ) <notaku@gmail.com> on Tuesday March 02, 2004 @03:16PM (#8443283) Homepage Journal
    Its not too late to watch: http://www.jpl.nasa.gov/mer/landing.cfm
  • by therealcaf ( 697590 ) on Tuesday March 02, 2004 @03:17PM (#8443294)
    can be found here [nasa.gov]
  • by neight9 ( 542480 ) on Tuesday March 02, 2004 @03:17PM (#8443306)
    two days late- for the free shrimp, nasa would have had to announce by 29-Feb.
  • by cmowire ( 254489 ) on Tuesday March 02, 2004 @03:18PM (#8443309) Homepage
    No, comets contain water-ice. In a vaccum, ice subliminates into water vapor without an intervining liquid step. Neither water vapor nor ice can support "life as we know it".

    The big thing here is that there was a body of water for some geologically continuous amount of time, which implies that there still is the potential for "life as we know it" on Mars.
  • Re:So much... (Score:1, Informative)

    by AyeFly ( 242460 ) on Tuesday March 02, 2004 @03:18PM (#8443313)
    lol, the above comment was not offtopic, if you would read slashdot more, you would see that todays poll asked what Nasa's announcement was, and the last option was Cowboyneal saving money on his auto insurance. so, before marking things as offtopic...make sure you doing so out of ignorance.
  • Re:Where did it go? (Score:5, Informative)

    by MalaclypseTheYounger ( 726934 ) on Tuesday March 02, 2004 @03:21PM (#8443391) Journal
    Yes, floats off into space, or turns into ice. There is very little atmosphere, so there is some speculation that the water is in liquid form under the Mars surface somewhere, and it eventually gets pushed up to the surface where it instantly evaporates into water vapor. The thin atmosphere sends this water vapor off into space, or it eventually collects at the two polar ice caps.
  • by aacool ( 700143 ) <aPERIODamanlamba2gmail.com minus punct> on Tuesday March 02, 2004 @03:23PM (#8443422) Journal
    Of the elements known to exist in the body, some, possibly all, are necessary to life. They are carbon, hydrogen, nitrogen, oxygen, potassium, sodium, iron, copper, manganese, zinc, magnesium, lithium, phosphorus, sulphur, chlorine, iodine, barium, silicon.

    Also, Methionine is an essential amino acid that is not synthesized by the body and must be obtained from food. It is one of the "sulphur-containing" amino acids and is important in many body functions.

    It is likely that sulphur, coupled with the different ferrous hydrides can produce viable conditions for life.

  • Re:So what? (Score:5, Informative)

    by stratjakt ( 596332 ) on Tuesday March 02, 2004 @03:23PM (#8443427) Journal
    The common knowledge was that the ice caps are carbon dioxide ice - dry ice.

  • NASA TV (Score:2, Informative)

    by markclong ( 575822 ) on Tuesday March 02, 2004 @03:24PM (#8443452)
    I found the live video from NASA here:

    http://www.nasa.gov/multimedia/nasatv/index.html [nasa.gov]

    They are talking about it right now it is real interesting.
  • NASA Press Release (Score:5, Informative)

    by athorshak ( 652273 ) on Tuesday March 02, 2004 @03:24PM (#8443455)
    No link in the article. Here is the press release: NASA Press Release [nasa.gov]
  • Re:So what? (Score:5, Informative)

    by cmowire ( 254489 ) on Tuesday March 02, 2004 @03:25PM (#8443467) Homepage
    Liquid water on Mars required the atmospheric pressures to be higher than they are right now. There was no proof, only speculation, that this was the case. Now there's something closer to proof.
  • by SkreamNet ( 610802 ) on Tuesday March 02, 2004 @03:26PM (#8443488) Homepage
    Obviously you've never had one of those air plants you never have to water! Pulls moisture from the air...

    (Hoping I don't sound stupid)
  • by Anonymous Coward on Tuesday March 02, 2004 @03:27PM (#8443490)
    As far as Christianity is concerned, where in the Bible does it say life only exists / was created on earth?

    Genesis would be a good place to start. Only Earth is ever mentioned as the place where god created life.

    Genesis does say that god created the heavens and the earth but nowhere does it say that god created life anywhere but Earth.

    Of course the excuse, the same that is used to explain the story of Noah, is that god created life elsewhere but it just wasn't written down.

    For reference [awitness.org]

  • Sample Return? (Score:4, Informative)

    by applemasker ( 694059 ) on Tuesday March 02, 2004 @03:27PM (#8443493)
    Sadly, while the current NASA programs envision a sample return "at some point," nothing is even close to being on the drawing boards, let alone atop a rocket --

    http://nssdc.gsfc.nasa.gov/planetary/mars_2003_05. html

  • Re:Where did it go? (Score:1, Informative)

    by Anonymous Coward on Tuesday March 02, 2004 @03:27PM (#8443495)
    I believe the preeminent theory is that water vapor near the top of the atmosphere can "boil" into space if the vapor pressure is greater than the force holding the vapor in the gravity well. Just like water vapor escaping a boiling pot, except the "air" is waaaaay thinner.

    Or of course it could be reacting en masse with something, like iron, but IIRC the most likely process is "boiling".

  • by drmike0099 ( 625308 ) on Tuesday March 02, 2004 @03:29PM (#8443542)
    They mentioned that they are going to go check the nearby rock outcropping named "Big Bend" and do basically the same that they did on this rock, in order to see if these rocks were laid down there. I think they're checking exactly that, i.e. whether or not this whole area is laid down with rocks of the same origin (soaked in water), or if they were thrown here by a collision or something.

    They said that they weren't sure if the rocks were sedimentary or not. From the sounds of it they aren't, but they did happen to be "soaked in water" or whatever the quote was, allowing the concretions to form in spaces in already existing rock. They haven't found any evidence of layering yet, as far as I know, which would mean sedimentary.
  • NASA Press Release (Score:4, Informative)

    by acherrington ( 465776 ) <acherrington@gma ... m minus caffeine> on Tuesday March 02, 2004 @03:29PM (#8443544)
    Scientists have concluded the part of Mars that NASA's Opportunity rover is exploring was soaking wet in the past.

    Evidence the rover found in a rock outcrop led scientists to the conclusion. Clues from the rocks' composition, such as the presence of sulfates, and the rocks' physical appearance, such as niches where crystals grew, helped make the case for a watery history.

    "Liquid water once flowed through these rocks. It changed their texture, and it changed their chemistry," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the science instruments on Opportunity and its twin, Spirit. "We've been able to read the tell-tale clues the water left behind, giving us confidence in that conclusion."

    Dr. James Garvin, lead scientist for Mars and lunar exploration at NASA Headquarters, Washington, said, "NASA launched the Mars Exploration Rover mission specifically to check whether at least one part of Mars ever had a persistently wet environment that could possibly have been hospitable to life. Today we have strong evidence for an exciting answer: Yes."

    Opportunity has more work ahead. It will try to determine whether, besides being exposed to water after they formed, the rocks may have originally been laid down by minerals precipitating out of solution at the bottom of a salty lake or sea.

    The first views Opportunity sent of its landing site in Mars' Meridiani Planum region five weeks ago delighted researchers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., because of the good fortune to have the spacecraft arrive next to an exposed slice of bedrock on the inner slope of a small crater.

    The robotic field geologist has spent most of the past three weeks surveying the whole outcrop, and then turning back for close-up inspection of selected portions. The rover found a very high concentration of sulfur in the outcrop with its alpha particle X-ray spectrometer, which identifies chemical elements in a sample.
    "The chemical form of this sulfur appears to be in magnesium, iron or other sulfate salts," said Dr. Benton Clark of Lockheed Martin Space Systems, Denver. "Elements that can form chloride or even bromide salts have also been detected."

    At the same location, the rover's Mossbauer spectrometer, which identifies iron-bearing minerals, detected a hydrated iron sulfate mineral called jarosite. Germany provided both the alpha particle X-ray spectrometer and the Mossbauer spectrometer. Opportunity's miniature thermal emission spectrometer has also provided evidence for sulfates.

    On Earth, rocks with as much salt as this Mars rock either have formed in water or, after formation, have been highly altered by long exposures to water. Jarosite may point to the rock's wet history having been in an acidic lake or an acidic hot springs environment.

    The water evidence from the rocks' physical appearance comes in at least three categories, said Dr. John Grotzinger, sedimentary geologist from the Massachusetts Institute of Technology, Cambridge: indentations called "vugs," spherules and crossbedding.

    Pictures from the rover's panoramic camera and microscopic imager reveal the target rock, dubbed "El Capitan," is thoroughly pocked with indentations about a centimeter (0.4 inch) long and one-fourth or less that wide, with apparently random orientations. This distinctive texture is familiar to geologists as the sites where crystals of salt minerals form within rocks that sit in briny water. When the crystals later disappear, either by erosion or by dissolving in less-salty water, the voids left behind are called vugs, and in this case they conform to the geometry of possible former evaporite minerals.

    Round particles the size of BBs are embedded in the outcrop. From shape alone, these spherules might be formed from volcanic eruptions, from lofting of molten droplets by a meteor impact, or from accumulation of minerals coming out of solution inside a porous, water-soaked rock. Opportunity's observations that the sp
  • Read NASA's Weblog (Score:4, Informative)

    by LinuxMacWin ( 79859 ) on Tuesday March 02, 2004 @03:30PM (#8443550)
    http://spaceflightnow.com/mars/mera/statustextonly .html
  • Re:Where did it go? (Score:3, Informative)

    by Anonymous Coward on Tuesday March 02, 2004 @03:30PM (#8443554)
    The short answer is that Mars magnetic shield died, and the water probably was stripped away with the martian atmosphere by the solar wind. See more here: pbs.org [pbs.org]
  • Anybody out there like to comment? Is it a possibility? Could we come back with another rover and get Opportunity working again after it runs out of juice?

    Opportunity's batteries will be dead (as in won't charge) inside a year of landing. Since the little guy can't rove without a stored supply of juice, he'll be as good as dead. That's actually one reason why scientists had wanted to use an RTG on the mission. An RTG could have kept it running for years, and in fact would have been one of the LAST components to kick the bucket. Sadly, NASA doesn't want another PR problem like with the Cassini probe.

  • by mpost4 ( 115369 ) * on Tuesday March 02, 2004 @03:36PM (#8443649) Homepage Journal
    How. Tell me where the Bible, says that God did not make other life. It does say that God is infinite. In fact a Christian can easily accept life on another plant because, if God is infinite, that would lead to Him being infinitely creative. So why would he stop with life on earth.

    Also as to the central reason for Christianity is that sin affects humans (read man on earth) how does that affect there being life on other earths.

    C.S Lewis also had a sci-fi book about life on other plants.
  • Free Food? (Score:5, Informative)

    by WebGangsta ( 717475 ) on Tuesday March 02, 2004 @03:41PM (#8443707)
    Does this mean that we ARE going to get free jumbo shrimp [longjohnsilvers.com] or not?

    Crap. Fine print says...

    If NASA's Mars Exploration Mission team discovers conclusive evidence that an oceanic body of water currently exists or previously existed on the planet Mars, and an Official Declaration of such existence is made on or before February 29, 2004, Long John Silver's will offer every person in the United States the opportunity to obtain one (1) free Giant Shrimp (Approximate Retail Value of $0.79) ("Free Giant Shrimp") at participating Long John Silver's(R) restaurants in the United States.
    If only they could have booked the conference room for the press conference 2 days ago instead of using it to hold Jerry's retirement party.

    'cause I *really* wanted to have that free jumbo shrimp.


  • Re:So what? (Score:2, Informative)

    by SB9876 ( 723368 ) on Tuesday March 02, 2004 @03:43PM (#8443726)
    Actually, the standard line for several years is that the polar ice caps are a mix of CO2 and water ice. It's fairly clear that there is still a very significant amount of sold water on Mars. The contention these days is how prevalent liquid water is.
  • by Hoi Polloi ( 522990 ) on Tuesday March 02, 2004 @03:46PM (#8443782) Journal
    The results they are finding imply water was in a liquid state for a significant amount of time. It was long enough for hydrated minerals to form and salt lake signatures (sulfur and bromine deposits) to form, similar to what forms in dry salt lakes.
  • by SB9876 ( 723368 ) on Tuesday March 02, 2004 @03:48PM (#8443812)
    While it's true that the elements above and Methionine (and several other amino acids as well) are required for humans, most free-living organisms can generate all of the amino acids from scratch.

    Aside from sulfur, iron, phosphorus, monovalent and divalent cations most of the other trace elements are required in levels so low that just about any random location will have enough to suffice.
  • by LordKazan ( 558383 ) on Tuesday March 02, 2004 @03:50PM (#8443827) Homepage Journal
    I was listening to the broadcast - these are sedimentary rocks -- notice how they kept pointing out the layering? Also talking about laying down chemicals - also concretions, etc that entire region is sementary
  • by Anonymous Coward on Tuesday March 02, 2004 @03:51PM (#8443849)
    As far as Christianity goes, it only refutes that portion of Christianity that doesn't believe in the Bible. Hebrews 1:1-2:

    GOD, who at sundry times and in divers manners spake in time past unto the fathers by the prophets,

    2 Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds;

    That would be worlds, PLURAL.
  • Re:Men are from Mars (Score:3, Informative)

    by metlin ( 258108 ) on Tuesday March 02, 2004 @03:51PM (#8443851) Journal
    Nonsense! We're all the hairdressers and telephone sanitizers out here buddy.

    Them Martians then screwed it up with that whatchacallit infection and went phut!

    Why do you think reality shows are so popular?
  • by yellena ( 79174 ) * on Tuesday March 02, 2004 @03:52PM (#8443859) Homepage
    The batteries were designed to have a lifetime of less than a year. It won't matter if the solar panels are operating at 100%, the batteries will stop holding a charge.
  • by morton2002 ( 200597 ) on Tuesday March 02, 2004 @04:06PM (#8444027)
    Mars has a very weak magnetic field since we speculate that its core has mostly cooled. This means that the planet is poorly protected from harsh solar and cosmic radiation, which is strong enough to break down water into oxygen and hydrogen. These atoms would indeed just float off into space, since the gravatational pull of the planet is not strong enough to retain such light atoms.

    That's why I'm not holding out much hope for terraforming Mars. But that doesn't mean we can't still live on it, just in protected chambers on the surface.
  • by edxwelch ( 600979 ) on Tuesday March 02, 2004 @04:07PM (#8444041)
    Water alone isn't enough to create life. You need that water to exist for millions of years. So, the next task is to try to determine how long that water existed for.
  • by Biff Stu ( 654099 ) on Tuesday March 02, 2004 @04:20PM (#8444208)
    I'm assuming that you're confused by the astronomy lingo. Many astrophysicists use the term "water-ice" to refer to frozen water, as opposed to other frozen materials such as methane, and other small hydrocarbons. As a physical chemist, the terminology annoys me, but that's the way they talk. So when you hear somebody from NASA talk about water-ice, they are referring to good old frozen water, not a water-ice equilibrium. For the record, in a vacuum, liquid water is not thermodynamically stable and water does indeed sublime. (Just like frozen CO2 sublimes.) However that certainly doesn't mean that ice can't exist in a vacuum. It just needs to be sufficiently cold that the vapor pressure is negligable. Since comets spend most of their lives out in the Kuiper belt, they are indeed plenty cold. When a comet approaches the sun, the comet heats up and water, along with other volatile compounds, does indeed sublime.
  • Re:Key point (Score:5, Informative)

    by mikerich ( 120257 ) on Tuesday March 02, 2004 @04:22PM (#8444231)
    Purely out of interest, what are the chances (in percentage) that the average sample of, say 1 kg of earth based sedinmentary rock would have fossils in it?

    Depends on the type of rock and what scale you are looking at. For instance if you look at a wind-blown sandstone you'll be hard pushed to find a fossil on any scale, look at a marine sandstone and there is a good chance of finding something.

    But then you have certain limestones which are almost pure fossil contents - fractured shells and the like - all the way through to materials like chalk or diatomaceous clay which are made entirely from microscopic fossil shells.

    So the answer from a geologist is - it depends where you look and how hard.

    Best wishes,

  • Jarosite, defined (Score:5, Informative)

    by RobertB-DC ( 622190 ) * on Tuesday March 02, 2004 @04:27PM (#8444297) Homepage Journal
    The NASA scientist held up a sample of Jarosite. For the curious, here's a definition [galleries.com]. Note -- the page referenced has several very cool links for more information.

    Chemistry: KFe3(SO4)2(OH)6, Potassium Iron Sulfate Hydroxide.
    Class: Sulfates
    Group: Alunite
    Uses: Only as mineral specimens.
    Jarosite is not a common mineral. It is closely related to the mineral natrojarosite. Jarosite is isostructural with natrojarosite which means that they have the same crystal structure but different chemistries. In this case, jarosite contains potassium instead of natrojarosite's sodium (natro is derived from the Latin for sodium, natrium, from where sodium gets its symbol, Na). The two minerals are difficult to distinguish without a chemical test.

    Both minerals are isostructural with alunite with a formula of KAl3(SO4)2(OH)6, who lends its name to the Alunite Group of which all three minerals belong.

    The symmetry of jarosite is the same as the members of the Tourmaline Group. Crystals of jarosite however do not form prismatic crystals like those of the typical tourmaline mineral. Jarosite's crystals are more flattened and resemble nearly cubic rhombohedrons. The "rhombohedrons" are actually a combination of two trigonal pyramids.

    Color is an amber yellow or brown.
    Luster is vitreous to resinous.
    Transparency: Crystals are transparent to translucent.
    Crystal System is trigonal; 3 m
    Crystal Habits include tabular to flattened rhombohedral looking crystals. The "rhombohedrons" are actually a combination of two trigonal pyramids. Crystals are somewhat scarce and small, more commonly as earthy masses, films or crusts, botryoidal and granular.
    Cleavage is good in one direction but only seen in the larger crystals.
    Fracture is uneven.
    Hardness is 2.5 - 3.5.
    Specific Gravity is approximately 2.9 - 3.3 (average to slightly heavy for translucent minerals, but hard to obtain from crusts)
    Streak is a pale yellow.
    Associated Minerals are barite, turquoise, galena, goethite, limonite, hematite and other iron minerals.
    Notable Occurrences include Jaroso ravine, Sierra Almagrera, Spain and Iron Arrow Mine, Colorado; Maricopa Co., Arizona; Idaho and California, USA.
    Best Field Indicators are crystal habit, associations, color and hardness.
  • Re:So what? (Score:5, Informative)

    by Anonymous Coward on Tuesday March 02, 2004 @04:32PM (#8444366)
    The common knowledge was that the ice caps are carbon dioxide ice - dry ice.

    This is 5, Informative in a sneaky small print kinda way. Yes, common knowledge was that the caps are carbon dioxide.

    Today common knowledge is that the ice caps are a mix of CO_2 and water. In the last couple years, there has been mounting evidence that it is actually mostly water ice, with some CO2.

    Google mars polar caps if you don't beleive me.

    Posted anonymously 'cause most moderators today wouldn't notice anyways.
  • by aacool ( 700143 ) <aPERIODamanlamba2gmail.com minus punct> on Tuesday March 02, 2004 @04:44PM (#8444520) Journal
    From Nasa: What is the atmosphere of Mars made up of? ANSWER from the Internet: LFM Web pages - [nasa.gov] The atmosphere of Mars is broken down as follows:
    95.32% Carbon Dioxide - CO2
    2.7% Nitrogen - N2
    1.6% Argon - Ar
    0.13% Oxygen - O2
    0.07% Carbon Monoxide - CO
    0.03% Water - H2O
    0.00025% Neon - Ne
    0.00003% Krypton - Kr
    0.000008% Xenon - Xe
    0.000003% Ozone - O3

    This does not take into account nitrates in the ground, which might have contributed to atmospheric nitrogen in the past. Also, the water % in the table above is probably going to be revised, perhaps, studies on Nitrogen density are likely.

    Further, nitrosomas and nitrobacter are extremely common bacteria in earth water - ask anyone who's run an aquarium - I predict they may be among the first bacteria discovered on Mars.

    My .02 cents

  • Re:Key point (Score:5, Informative)

    by Chester K ( 145560 ) on Tuesday March 02, 2004 @05:08PM (#8444822) Homepage
    Couldn't the machines and devices we have sent have just as good of a chance to contaminate Mars than humans?

    Machines and devices can be sterilized, autoclaved, and what have you, to remove any presence of life, even at the bacterial level.

    Human beings can't have such precautions taken. If we're going to send anything to Mars, machines are by far the safest option.
  • Re:Key point (Score:5, Informative)

    by hetairoi ( 63927 ) on Tuesday March 02, 2004 @05:10PM (#8444845) Homepage
    I don't think so, since the rovers are "among the most biologically clean spacecraft ever launched from Cape Canaveral." [spacedaily.com]

    I doubt it would be as easy to scrub all the nasties off a human. Even if they wear protective suits there would be a greater chance of contamination.

  • by praedor ( 218403 ) on Tuesday March 02, 2004 @05:18PM (#8444928) Homepage

    Ahem. _The_RNA_World_. Get it. Read it. Accept it. I worked with the authors during a lab rotation at the University of Utah.

    Points to keep in mind: amino acids and nucleic acids are abundant in the universe. They form naturally in the interstellar medium. They are detected in nebulae all over the sky. They are part of the basic building blocks that exist all over the universe.

    Next point: there are numerous other helpful items in nature that lead to SELF ORGANIZATION. Self organization is an area of scientific study if you are inclined.

    Next point: there are various scaffolds available that can act as substrates for projected proto lifeforms (self-replicating nucleic acids, RNA molecules).

    All life involves is basic chemistry that exists everywhere in nature, abiotic and biotic.

    Combine all the above naturally occurring elements and you have all that is needed to produce, ultimately, life from non-life. Life is not magic. It is ultimately about self-replicating, sustained, chemical reactions.

    It is possible to derive self-replicating RNA molecules. Once such a molecule exists, it is subject to evolution, plain and simple. There are no "buts", there are not "wait a minutes". Once you have a self-replicating ANYTHING, it is immediately subject to evolutionary forces. Given time and range(and we are talking BILLIONS of years here and a virtually infinite sized universe) you have plenty of time and opportunity to evolve virtually any type of possible lifeform. No magic. Just plain old chance, chemistry, and evolution. All plain logic and mathematical simplicity.

    It took something like a billion years for life to evolve on earth into a form that is recognizable as life. A billion years is a LONG time. It is much longer than you imagine, much longer than you CAN imagine. You cannot take in that amount of time and really get a grasp on what it really means. A billion years is a long-frickin'-time. Time enough.

  • Not simply "might" (Score:3, Informative)

    by ciphertext ( 633581 ) on Tuesday March 02, 2004 @05:24PM (#8444986)

    They have found extremely compelling evidence that there was/is water on mars. Essentially the only questions that remain are, "How much water?" and "How long was there water?". True, the evidence isn't 100% conclusive, but it is definitely within a range that several scientists are willing to place their reputations in jeopardy to announce.

  • by edxwelch ( 600979 ) on Tuesday March 02, 2004 @05:28PM (#8445011)
    Puting nuclear batteries would make little difference to the lifespan of the project, because it's not determined by power alone. There is a possiblity that the electronics or mechanics will fail before the power runs out due to the extreem daily temperture change
  • by sonpal ( 527593 ) <slashdot@sonpalte[ ]com ['ch.' in gap]> on Tuesday March 02, 2004 @05:48PM (#8445230) Homepage
    The two rovers cost $820 million together, see here. [space.com] I understand that the parent was meant to be funny, but I found the amount mind-boggling, and had to look it up.
  • Re:Key point (Score:5, Informative)

    by Anonymous Coward on Tuesday March 02, 2004 @05:55PM (#8445307)
    It would be highly variable. In a limestone or chert composed entirely of macroscopic or microscopic shells, it would be nearly 100% fossils -- the rock is *made* of biological remains. These deposits can comprise cubic kilometres of rock over vast areas on Earth. In other sedimentary rocks, fossil content would be lower, or almost zero (e.g., wind-deposited sands are pretty poor). Fossil content is highly variable, and depends upon the geological environment at the surface, the age (e.g., Phanerozoic is much richer in fossils than the Precambrian), and biological factors, as well as the scale of the observations (macroscopic versus microscopic). It also depends greatly on the compositions in the original organism -- did it produce a mineral shell, did it have tough organic material that preserves easily (e.g., spores and pollen)? Hell, there are cases where fossils are known from igneous rocks (e.g., trees encased in lava flows) and plenty of metamorphic rocks too (e.g., just about any fossiliferous sedimentary rock can be metamorphosed to a degree before the fossils are destroyed). Bacterial fossils can occur just about anywhere that suitable mineralization is simultaneously occurring, but they can be tricky to distinguish from non-biological processes (even on Earth, where we *know* there is/was life). Some biological molecules are also recognizable ("biomarkers"), even if the body of the organism is not preserved.

    So, I don't have a good answer for, but based on intuition, I would guess between 1 to 10% on average for Earth. There are vast areas, however, where you could drive for miles and find 100%, or 0%. Because the distribution is so variable, and we can only speculate on the range of likely environments and rock types on Mars, this would not be much of a guideline.

    One thing is for certain, though -- it would take more than a couple of good rovers to eliminate the possibility for Mars.

  • Re:Key point (Score:3, Informative)

    by MadCow42 ( 243108 ) on Tuesday March 02, 2004 @05:59PM (#8445355) Homepage
    It's not so much a point of scrubbing the "nasties" OFF of a human... but OUT of a human. We're chalk full of bacteria inside and out, and wouldn't survive without them.

  • by Anonymous Coward on Tuesday March 02, 2004 @06:10PM (#8445455)
    The Canadian example you cite is a poor one, for two reasons:

    1) It did spew high-level radioactive material over a wide area, much of which was never recovered. Some of it was potentially highly dangerous stuff (i.e., lethal exposure in relatively short time), and there was a huge recovery effort. The main reason there were no deaths or injuries was its remote location, not lack of risk from it. Had it been in a populated area, no doubt some people would have picked it up and it probably would have resulted in illness, at least.

    2) Most importantly, it was not designed for containment survival during reentry like the RTGs are. It was exposed to space with little shielding, and it was designed so that the reactor could be separated from the rest of the satellite and boosted to a higher orbit (one from which it would hopefully not deorbit for a looong time, after most of the radioactivity had decayed). The Russians lost control of it shortly after launch and it crashed to Earth.

    I think it was called Cosmos 954.
  • by pclminion ( 145572 ) on Tuesday March 02, 2004 @06:21PM (#8445538)
    These atoms would indeed just float off into space, since the gravatational pull of the planet is not strong enough to retain such light atoms.

    That's not quite the right way to put it. Hydrogen can escape because it is light, yes, but not because gravity isn't "strong enough." Remember that gravity accelerates all objects equally (the falling feather and bowling ball experiment). An atom of hydrogen and an atom of lead would both fall toward the ground at exactly the same speed, and hit at the same time.

    Because hydrogen is so light, however, it has a much higher velocity for a given kinetic energy than any other kind of atom, so it is much easier for it to reach escape velocity via collisions with other gas particles.

  • by El ( 94934 ) on Tuesday March 02, 2004 @06:44PM (#8445730)
    It was a piece of the airbags, and Nasa didn't destroy it, it blew away... at least that is the most plausible explaination.
  • Mission Accomplished (Score:5, Informative)

    by QuantumFTL ( 197300 ) * on Tuesday March 02, 2004 @06:47PM (#8445757)
    Here at JPL, it is an interesting mixed feeling the scientists are having.

    On one hand, we've acomplished almost all of the stated goals of the mission. I saw the Long Term Planning briefing and the chart had item after item checked off... only the endurance section was left unfinished.

    Think about it. We landed not one but two fully functional rovers on mars, with the most comprehensive science package ever sent to another world. We have spectrometers of unmatched precision, we have the ability to examine betneath the surface of rocks and outcrops, and we've taken the most detailed pictures of mars ever recorded.

    We've explored rocks and craters and soils, and that was just the first few sols! All of this is an incredible accomplishment, especially considering the track record. The engineering part alone is enough to consider the mission a success.

    But since last week it's been clear to us here that we've found what we were looking for: evidence that clinches the case that Mars was once wet. That's when I say, "Mission Accomplished". That's more than many hoped to find, though we sent the mission as it is primarly because we expected this was *possible* if even somewhat unlikely.

    But we're not done yet. In fact if anything we have more questions to answer now. Mars has never failed to throw curve balls at us. There's all kinds of minerology that we're not sure about. We don't even know yet if this was just ground water, or actually lakes or oceans. But as long as these rovers still have life in them we'll continue to advance our scientific understanding of the planet.

    Regardless of what anyone thinks about the specifics of the President's plan, it's clear that public support for the program is very high now, considering that we have learned from our mistakes and have accomplished more than we could have hoped. I'm very optimistic that future missions will unravel many of the new mysteries we have discovered. It is truely, as they said on the briefing, a great time to be alive. The field of astrobiology is finally beginning to be taken seriously by the scientific community and even the public at large. We have seen that Faster, Better, Cheaper *can* work - as long as we don't try to bite off more than we can chew.

    I don't know when we'll actually have humans on Mars, but I'm hopeful that there's a real chance that in my lifetime (and maybe even my parents') we will find evidence of previous life on Mars. It'd be nice to know we're not quite alone.

    My congradulations to the science team for an incredible discovery, and I extend that to the taxpayers that graciously fund us, and to our supporters in all nations of this earth. We could not have made these discoveries without our valued partners in Europe, and they deserve to share much of the credit.

    I know some of you on slashdot ask why fund the space program. I hope that this makes it clear that you are getting your money's worth. Thanks for all of your support!

    Justin Wick
    Science Activity Planner Developer
    Mars Exploration Rovers
  • Re:Dune (Score:3, Informative)

    by HeghmoH ( 13204 ) on Tuesday March 02, 2004 @07:36PM (#8446265) Homepage Journal
    Last I checked, human life arose in sub-saharan Africa, which is currently one of the richest ecosystems you'll find anywhere. Human life didn't arise in North Africa or the Middle East. Maybe you meant civilization? Even so, there are plenty of examples of places where civilization arose that didn't turn into deserts.
  • by mark-t ( 151149 ) <markt@nerdfl[ ]com ['at.' in gap]> on Tuesday March 02, 2004 @10:00PM (#8447811) Journal
    I was, of course, kidding when I suggested teraforming Mars.

    Any attempt to teraform Mars would be futile because Mars does not have a magnetic field which would keep the atmosphere from being slowly stripped away by the solar wind as well as protecting the surface from much of the harmful radiation the sun emits continuously.

  • by QuantumFTL ( 197300 ) * on Tuesday March 02, 2004 @10:08PM (#8447866)
    Now we find another local planet with ancient water on it.. The next find I expect is simple life living on Mars.

    How can any religion survive that revelation?

    I know you're a troll but it's a decent question.

    I work at JPL on this mission, however I'm also a Christian. And as a Christian I believe personally that God made some damn cool stuff for us to explore. If we find past life on Mars (and believe me, we are a long ways away from that) that won't make me feel any worse about how I believe. I will feel more awe, not less, at what I see around us.

    I'm not advocating my religious beliefs but it's amazing how many people assume all Christians are violently against the existence of extraterrestrial life. The Bible says we are special compared to what else is on this planet, and nothing more. Personally I'd be surprised if God wouldn't make more awesome, different types of "people" to enjoy this crazy universe :)

    Justin Wick
    Mars Exploration Rovers
  • by Anonymous Coward on Tuesday March 02, 2004 @10:38PM (#8448110)
    "Informative"? Yeesh.

    FeH doesn't mean anything, because iron has valence 2 or 3 in stable compounds.

    FeS3H2 doesn't spell anything but ignorance.

    Iron sulfate hydrate is FeSO4.n(H2O). "Hydrate" means it has water bound up with it.

    Congratulations on being able to count atoms on both sides -- and even multiply small integers, wow! -- but there's a lot more to chemistry than that.
  • Wrong (Score:2, Informative)

    by conan776 ( 723791 ) on Tuesday March 02, 2004 @10:40PM (#8448124)
    That's why the latin is more elucidating. You're fallacy is falling into a linguistic trap. Cogito ergo sum. Think do I, thus am I. The first premise is think, the rest follows. Counter arguments that you can't think that you've thought until you have thought are Zeno-eqsue (google Zeno frog well) or that you perhaps only think you are thinking (google Chuang Tzu dream butterfly) are self-evidently moot. Dang, the frog ate the butterfly again. I hate it when that happens.
  • Re:Key point (Score:2, Informative)

    by meiocyte ( 455845 ) on Tuesday March 02, 2004 @10:44PM (#8448157) Homepage
    No..actually it is not better. This is just a tautology. It's a valid argument, sure - but all you're doing is stating an arbitrary definition. I could just as easily say:

    There exists a bowling ball.
    I am defining this bowling ball as "I".
    Therefore "I" exists.

    This is also a valid argument. But like yours it misses the point. Where does the definition come from? What makes it valid?

    (Also, you've used "I" again, in your 2nd premise. Try not to use the word "I" as a subject before the conclusion that "I" exists..
    Yes, I do like to get this technical... isn't this slashdot?)
  • by cavac ( 640390 ) on Wednesday March 03, 2004 @12:44AM (#8448978) Homepage
    Probably yes. But it will take much longer than on mars.

    AFAIK, Mars lost much of it's atmosphere (and i assume its water as well because of the lowering atmospheric pressure) to the solar wind, because it has no magnetic field (or at least no global one), so the solar wind could rip the uppermost part of the atmosphere away.

    Of course, this process takes millions ans billions of years, but mars has been around a long time...
  • by crusher-1 ( 302790 ) on Wednesday March 03, 2004 @01:16AM (#8449150)
    Mars lost its magnetosphere eons ago. This caused the solar wind to blow away and boil off it's atmosphere over a few million years (a relatively short time all things considered).

    They have presently been doing research related to Earths fluxuations in its magnetosphere. At present the major indicators used to determine the stability (as we understand it) has been dropping. The speculation is that we are going to eventually have a poll flip (north becomes south and vice verse). In the interim their will be a period of time where holes (for lack of a better word) similar to those existing at the north and south poles that cause the Aurora Borialis will exist in multiples. In otherwords, during this period of time these will drift around the surface of the earth until the fields stablize. The results will be spectacular night sky showings in such unlikely places as Paris or Hong Kong or where have you - the downside is the exposure to solar radiation of people under these zones.

    The magnetosphere is dependent on the internal heat generated by the Earths core and it's rotation. In Mars case it is speculated that its core went cold a very long time ago and this was the primary reason its magnetosphere failed and let the solar wind work away the atmosphere.
  • by QuantumFTL ( 197300 ) * on Wednesday March 03, 2004 @02:04AM (#8449369)
    Maybe you could ask your chiefs to release more technical details, especially on the drive system and the autonomous waypoint navigation.

    Unfortunately no can do... all that stuff is ITAR sensitive [pmdtc.org].

    It makes a lot of what we do very difficult (some would say unnecessarily so) and keeps us from sharing some of the most awesome details with the public at large.

    This is the same treaty that limits the export of strong crypto, and has experienced so much resistence from geeks around the country that there is a civil disobedence [offshore.com.ai] process that has been going on online. I'm not advocating this but I find it interesting that people are willing to be "arms traffickers" to stop this kind of law.

    So if you want more details, you're going to have to ask your politician for it, because unfortunately it can't come from us :(.

    *NOTE: This post is not a criticsm of government policies and does not in any way reflect NASA opinions, only publically stated policy.

    Justin Wick

    Mars Exploration Rovers

    P.S. Good luck with your robot. I'm thinking about making my own rover sometime... hmm...
  • by mark-t ( 151149 ) <markt@nerdfl[ ]com ['at.' in gap]> on Wednesday March 03, 2004 @03:42AM (#8449814) Journal
    Right... but it's still impossible, regardless of what they do to the surface environment because of the lack of a magnetic field. This is an absolutely mandatory prerequisite in order to even have the *HOPE* to make a planet habitable. Without it, any changes they might be able to make to the upper atmosphere to try to shield from radiation (such as an ozone layer) would be moot because it would get stripped away by the solar wind.

    Teraforming techniques concentrate on climate and environmental changes, but don't talk about changing fundamental geological properties of the planet as a whole such as giving one a magnetic field when it didn't have one previously.

  • The Real Answers (Score:2, Informative)

    by turgid ( 580780 ) on Wednesday March 03, 2004 @06:23AM (#8450361) Journal
    The real answers can be found here [davidicke.com]. David Icke knows the TRUTH. It's the lizards from outer space. And the British Royal Family. And the Freemasons. And the Devil Worshippers. And he doesn't take his pills.
  • Re:Key point (Score:2, Informative)

    by Gollum ( 35049 ) on Wednesday March 03, 2004 @09:24AM (#8450962)
    No, it is just pure logic.

    If L is Life and
    E is Evidence of Life, then

    E ===> L
    !E =/=> !L

    That is:

    Evidence of Life implies that there was life, but lack of evidence of life does not imply that there was no life.

    For the same reason, not finding a vulnerability cannot prove that software is secure

"There is no distinctly American criminal class except Congress." -- Mark Twain