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Started by Robert Galyen
Sun, 12 Oct 1986 03:52
Martian meteors on earth
Author: Robert Galyen
Date: Sun, 12 Oct 1986 03:52
Date: Sun, 12 Oct 1986 03:52
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In the Saturday (Oct. 11) Rocky Mountain News there is a article about 8 meteors found in India, Egypt, France, Anarctica, Nigeria, Brazil, and United States that are suppose to have originated from Mars, based on similar geologic characteristic and chemical composition. Speculation is the meteors were blasted into space when a large asteriod or comet impacted the martian surface resulting in generation of jets of hot gases which could have propeled meter sized objects into space, exceeding the martian escape velocity of 11,300 mph. The article doesn't mention a size for the impacting object other than asteriod or comet, is there a size definition for these planetary inter- lopers? Is there any way of determining the minimum size required of an impacting object? Also, it seems that the proximity of the moon, the low lunar gravity, and some of the larger impact events would have combined to send lunar 'litho' grams to earth. Comments, speculations? --robert-- ------------------------------------------------------------------------ Cold hearted orb that rules the night, That steals the color from our sight, Red is gray and yellow is white, But we decide which is right, And which is an illusion. The Moody Blues Knights in White Satin
Re: Martian meteors on earth
Author: Courtenay Footman
Date: Thu, 16 Oct 1986 02:14
Date: Thu, 16 Oct 1986 02:14
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In article <686@scicom.UUCP> galyen@scicom.UUCP (Robert Galyen) writes: > > >In the Saturday (Oct. 11) Rocky Mountain News there is a article about 8 >meteors found in India, Egypt, France, Anarctica, Nigeria, Brazil, and >United States that are suppose to have originated from Mars, based on >similar geologic characteristic and chemical composition. Speculation is >the meteors were blasted into space when a large asteriod or comet impacted >the martian surface resulting in generation of jets of hot gases which could >have propeled meter sized objects into space, exceeding the martian escape >velocity of 11,300 mph. > >The article doesn't mention a size for the impacting object other than >asteriod or comet, is there a size definition for these planetary inter- >lopers? Is there any way of determining the minimum size required of an >impacting object? Also, it seems that the proximity of the moon, the low >lunar gravity, and some of the larger impact events would have combined to >send lunar 'litho' grams to earth. > See the latest Science for an article about these eight objects. It gives the result of a detailed (2-D) calculation of how these objects could have been thrown off Mars. Basically it involves a ~1 Km meteorite traveling at ~7.5 Km/sec that impacts at an angle of 20 to 60 degrees; among other things, a large, dense, fast jet of gas forms that can (relatively) gently push things off the surface. That `gently' is important; there is more than enough energy to blast something off Mars, but accelerating it without vaporizing it is tricky. Also, many meteorites are from the moon; I don't remember the exact numbers, but I think that there are more of them from the moon than Mars. -- -------------------------------------------------------------------------------- Courtenay Footman ARPA: cpf@lnsvax.tn.cornell.edu Lab. of Nuclear Studies Usenet: cornell!lnsvax!cpf Cornell University Bitnet: cpf%lnsvax.tn.cornell.edu@WISCVM.BITNET
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