From: LARRY KLAES (ljk4_at_msn.com)
Date: Tue Feb 17 2004 - 05:49:43 PST
>COMETS SPREAD EARTH-LIFE AROUND GALAXY, SAY SCIENTISTS
>Cardiff University release
>
>9 February 2004
>
>If comets hitting the Earth could cause ecological disasters,
>including
>extinctions of species and climate change, they could also disperse
>Earth-
>life to the most distant parts of the Galaxy. The "splash-back" from
>a
>large comet impact could throw material containing micro-organisms out
>of
>the planet's atmosphere, suggest scientists from Cardiff University
>Centre
>for Astrobiology.
>
>Although some of this outflowing material might become sterilized by
>heat
>and radiation, they believe that a significant fraction would survive.
>As
>the Earth and the Solar system go round the centre of the galaxy every
>240
>million years, this viable bacterial outflow would infect hundreds of
>millions of nascent planetary systems on the way. Hence, they
>suggest,
>the transfer of Earth life across the galaxy is inevitable. These
>ideas
>are discussed in detail in two papers appearing in the current issue
>of
>the Monthly Notices of the Royal Astronomical Society. The authors of
>the
>two papers are Professor Chandra Wickramasinghe and Dr. Max Wallis, of
>the
>Cardiff Centre for Astrobiology, and Professor Bill Napier, an
>astronomer
>at Armagh Observatory and an Honorary Professor at Cardiff University.
>
>
>Interstellar routes for transmission of micro-organisms supports the
>view
>that life may not have originated on Earth but arrived from elsewhere,
>
>strengthening the panspermia hypothesis that Professor Wickramasinghe
>and
>the late Sir Fred Hoyle had been developing since 1974. It is known
>that
>boulders and other debris may be thrown from the Earth into
>interplanetary
>space. Professor Napier finds that collisions with interplanetary
>dust
>will quickly erode the ejected boulders to much smaller fragments and
>that
>these tiny, life-bearing fragments may be driven out of the solar
>system
>by the pressure of sunlight in a few years. The solar system could,
>therefore, be surrounded by an expanding "biodisc", 30 or more light
>years
>across, of dormant microbes preserved inside tiny rock fragments. In
>the
>course of Earth history there may have been a few dozen close
>encounters
>with star-forming nebulae, during which microbes might be injected
>directly into young planetary systems. If planets capable of
>sustaining
>life are sufficiently common in the Galaxy, the Cardiff based
>scientists
>conclude that this mechanism could have infected over 10,000 million
>of
>them during the lifetime of our Galaxy.
>
>Dr. Wallis and Professor Wickramasinghe have also identified another
>potential delivery route. They point out that fertile Earth ejecta
>would,
>on impact, bury themselves in the radiation-shielded surface layers of
>
>frozen comets. A belt of such comets, the Edgeworth-Kuiper belt, lies
>
>beyond the planetary system. This belt gradually leaks comets into
>interstellar space, some of which will eventually reach
>proto-planetary
>discs and star-forming nebulae. There they are destroyed by
>collisions
>and erosion, releasing any trapped micro-organisms and seeding the
>formative planetary systems.
>
>Contacts:
>Professor Chandra Wickramasinghe
>Centre for Astrobiology
>Cardiff University
>Phone: 029 2087 4201
>E-mail: Wickramasinghe_at_cardiff.ac.uk
>http://www.astrobiology.cf.ac.uk/
>
>Andrew Weltch
>Public Relations Office
>External Relations Division
>Cardiff University
>Phone: 029 2087 4731
>E-mail: WeltchA_at_cardiff.ac.uk
>
>Read the original news release at
>http://www.cf.ac.uk/news/03-04/040210.html.
>
>An additional article on this subject is available at
>http://www.universetoday.com/am/publish/comets_seeded_galaxy.html.
_________________________________________________________________
Say “good-bye” to spam, viruses and pop-ups with MSN Premium -- free trial
offer! http://click.atdmt.com/AVE/go/onm00200359ave/direct/01/
This archive was generated by hypermail 2.1.6 : Tue Feb 17 2004 - 05:56:36 PST