[meteorite-list] Meteorite Experiment Deals Blow To 'Bugs From Space' Theory

From: Pete Pete <rsvp321_at_meteoritecentral.com>
Date: Wed, 24 Sep 2008 17:40:52 -0400
Message-ID: <BAY141-W4292265807A69003E1D384F8450_at_phx.gbl>

Heyyyy, wait a minute!... If ablation is ~90%, aren't the "two centimetres" samples in the nosecone unrealistic?
Wouldn't samples the size of watermelons to small cars be more resonable, considering what their experiment concerns?

Cheers,
Pete






> From: baalke at zagami.jpl.nasa.gov
> To: meteorite-list at meteoritecentral.com
> Date: Wed, 24 Sep 2008 14:17:30 -0700
> Subject: [meteorite-list] Meteorite Experiment Deals Blow To 'Bugs From Space' Theory
>
>
> http://www.ndtv.com/convergence/ndtv/story.aspx?id=NEWEN20080066592
>
> Meteorite experiment deals blow to 'bugs from space' theory
> Agence France-Presse
> September 24, 2008
>
> A novel experiment has dealt a setback to a theory that life on Earth
> was kick started by bacteria that hitched a ride on space rocks.
>
> The "pan-spermia" hypothesis is that cells were transported to the
> infant Earth on rocks that were bumped off other planets or even came
> from another star system.
>
> The theory gained a boost in 1996 when a group of US scientists proposed
> that a famous meteorite found in Antarctica held traces of fossilised
> bacteria that once lived on Mars.
>
> Seeking to find out more, European scientists have devised "artificial
> meteorites" to see what happens when rocks bearing fossil traces and
> living bacteria are exposed to the fiery heat of entering Earth's
> atmosophere.
>
> In research to be unveiled on Wednesday, they attached small rocks two
> centimetres thick to a Russian unmanned Foton M3 capsule that was
> launched in September 2007 and returned to Earth 12 days later.
>
> The samples were imbedded on the capsule's heat shield, which reached a
> peak velocity of 7.6 kilometres per second or 27,200 kilometres, per
> hour during the controlled descent.
>
> The study was scheduled to be presented on Wednesday at the European
> Planetary Science Congress in Muenster, Western Germany.
>
> So far 39 meteorites have been found on Earth that have been attributed
> to a Martian origin. The notion is that they were knocked off the planet
> in the distant past by an asteroid impact. They then wandered in space
> before landing on earth.
>
> But all of these meteorites are of basalt, or volcanic origin. None is
> sedimentary. This has perplexed scientists, as there is abundant
> evidence for sediments on the Red Planet.
>
> Outcome of the experiment shows Martian sedimentary rocks could survive
> entry through Earth's atmosphere.
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_________________________________________________________________
Received on Wed 24 Sep 2008 05:40:52 PM PDT