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Mars Space Science

Rare Water-Rich Mars Meteorite Discovered 71


Rare Water-Rich Mars Meteorite Discovered

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  • Some questions (Score:2, Interesting)

    by Celarent Darii ( 1561999 ) on Thursday January 03, 2013 @11:23PM (#42471649)

    The article is very short on explanations. For instance:

    1/ When they say 'Martian meteorite' do they mean that it actually came from the surface of mars or rather than it's general origin was near to the orbit of mars?
    2/ What guarantees are there that this rock is actually from mars?
    3/ If so, how can you explain the parent meteor escaping the gravity well of mars? If this piece of rock is about a kilogram, then its entry mass must have been be quite large. The meteorite in California that was tracked with radar (the Sutton Mill's meteorite in 2008) and later collected had an estimated mass of 40,000 kg but only about 1 kg was recoverable from pieces much smaller than the one in the story.
    4/ Following this, it would seem an improbable event that a/ there would be some impact on mars that would send ejecta as large as 40000 kg out of mars orbit and that b/ this orbit would be towards the earth. Any impact that could send ejecta into escape velocity would almost have to be tangential to the surface, and even then it is difficult to see how such an impact could even produce large ejecta as the impact would skim more across the surface rather than into the interior of the planet.
    5/ usually dating of the material and its mineral composition leads to a supposition that it is of planetary origin. And yet this rock has a different material composition than martian rocks, as per the article. Thus it seems that the entire hypothesis that it came from mars should actually be questioned instead of inferring that mars had more water than because of the composition of this meteorite.

    Just how can they actually prove that the rock came from mars? It seems Occam's razor needs some sharpening.

    I remember not long ago that they were saying that the Corvid meteoroids were ejecta from the Giordano Bruno impact. This was proven false: []

  • Re:Two questions... (Score:4, Interesting)

    by mbone ( 558574 ) on Friday January 04, 2013 @01:19AM (#42472497)

    sounds a little BS to me

    "and you can rule out every planet / asteroid but Mars"
    where is this catalog of every single asteroid to ever come close to earth since creation of earth?

    The list of asteroids with an atmosphere and liquid water is rather short (as in, non-existant). That also rules out Venus and Mercury. The isotope data rules out the Earth (or the Moon). These arguments also rule out the Jovian satellites and stuff further out. Conversely, other isotope data make it clear these objects do come from within the solar system somewhere.

    This was all argued out at length in the 1980's and there were many skeptics, but they were eventually convinced. I remember being at a debate in Paris where one of the leading skeptics was reduced to saying that, although these came from a body very much like Mars, and not like any other solar system body, that didn't prove they are from Mars. That was about when he lost me. Now, this is regarded as well established and not controversial at all.

    "At some point, it is stopped"

    yea when its out of energy genius

    It has to get vaporized first.

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