Difference between revisions of "Meteoric iron"
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Revision as of 14:50, 19 February 2010
Given Mars' proximity to the asteroid belt and the long geological life of materials on its surface compared to Earth, meteoric iron will probably exist in significant abundance. The following questions on this probability need to be researched:
- How many asteroids cross Mars orbit vs. cross earth's orbit?
- Earth's larger cross-sectional area and gravity well draws a larger fraction of the nearby meteoroids to strike it than does Mars' gravity well. What is the numerical difference?
- Earth's atmosphere tends to stress stony meteoroids of less than about a hundred feet or so in diameter and more than some unknown diameter to the extent that they explode in the air and leave no trace but dust on the ground but slows 100 foot diameter iron meteoroids so they have less of a tendency to vaporize on hitting the ground. To what extent does this enrich the number of intact iron meteoroids available to be found on the Earth's surface as compared to a world with a negligible atmosphere?
- What are the lifetimes of iron meteorites, given the differences in geology (e.g. the typically more active erosion processes on Earth than on most of Mars, as indicated by e.g. the large difference in uneroded craters) and atmosphere (e.g. its oxygen which rusts exposed iron), on Mars and Earth respectively?
- Mars had water on its surface in the geologically recent past. What percentage of its surface was covered by water vs. the c. 2/3 of Earth covered by water? This water would have had an equilibrium level of dissolved carbon dioxide making a somewhat acid solution. To what extent would this have dissolved iron meteorites vs. rate that would occur in earth's lakes and oceans?
- At least one Mars rover found bits of meteoric iron -- how much does this effect the probability?