[meteorite-list] Re: Entry Burn [was Lunar Burn]
From: Mr EMan <mstreman53_at_meteoritecentral.com>
Date: Wed Aug 23 19:23:31 2006 Message-ID: <20060823232328.93275.qmail_at_web51011.mail.yahoo.com> Welcome back, Walter I'd like to point out that my original comment was intended to "desuggest" copper in favor of nickel. We who have done blowpipe mineral studies tend to think in that framework. Several years ago on my farm outside Ft Benning, Georgia I saw 2 nearly identical fireballs in the same sky location but they were on adjacent nights. Both were headed towards the Benning impact area, so I had doubts as to their true identity. Most notable was that both showed a pressure/bow wave clearly leading the dimmer fireball. The bow waves were orange in the center with green wings. Since the sighting of two identical fireballs on successive evenings is improbable, my inclination was that this might be "secret" rail gun experiments. The rail gun fires a Lucite slug with copper plate. Ergo the assumption that this was a "copper" blowpipe signature.( I now believe that these were true meteoroids not weapon's testing) Around that time there was a list discussion about "green meteors" and the consensus was that green from a meteor was due to nickel--copper being an extremely minor element found in meteorites. Thus the origin of that thought: nickel vs copper. There was also a lengthy discussion about the desire to do spectral analysis on fireballs as a signature for identifying possible meteoroid composition. I hadn't heard much since that time. I don't disagree that oxygen has a green spectral line, just that this was the first I heard of atmospheric oxygen as an emmiter in fireball reentry. I rarely see green as a color in fireballs with some Leonoids and the two specific fireballs I mentioned before as the notible exceptions. If anyone has specific links to the discussion of meteor spectrums, please share. Elton Received on Wed 23 Aug 2006 07:23:28 PM PDT |
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