[meteorite-list] Life on Earth 'Began on a Radioactive Beach'

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 15 Jan 2008 17:59:47 -0800 (PST)
Message-ID: <200801160159.RAA12803_at_zagami.jpl.nasa.gov>

http://www.telegraph.co.uk/earth/main.jhtml?view=DETAILS&grid=&xml=/earth/2008/01/09/scibeach109.xml

Life on Earth 'began on a radioactive beach'
By Nic Fleming
The Telegraph (United Kingdom)
January 9, 2008

Life on Earth began on a radioactive beach, a scientist claimed today.
 
According to computer models, deposits could collect at a beach's high
tide mark in sufficient quantity to trigger fission reactions

The sifting and collection of radioactive material by powerful tides
could have generated the complex molecules that led to the evolution of
carbon-based life forms - including plants, animals and humans.

While radiation may seem an unlikely candidate to kick-start life
because it breaks chemical bonds and splits large molecules, it also
crucially provides chemical energy needed to generate some of the basic
building blocks of life.

Zachary Adam, an astrobiologist at the University of Washington in
Seattle, has suggested the collection of radioactive material on a beach
as a new theory for the origins of life - to be added to the existing
long and varied list of hypotheses.

One is its emergence from a "primordial soup" of simple organic
chemicals accumulated on the surface of bodies of water within the
hydrogen-rich early atmosphere - formulated in the 1920's by English
geneticist J. B. S. Haldane and Russian biochemist Alexander Oparin.

Others include early life forming in inorganic clay, the initial energy
coming not from chemical reactions but from sunlight or lightening and
the arrival of microscopic seeds of terrestrial life on chunks of
meteorites or comets, and the intervention of a divine, intelligent
designer.

In work highlighted in this week's New Scientist magazine, Mr Adam
suggests the more powerful tides generated by the moon's closer orbit
billions of years ago compared to today could have sorted radioactive
material from other sediment.

According to his computer models, deposits could collect at a beach's
high tide mark in sufficient quantity to trigger the self-sustaining
fission reactions - as occur in natural seams of uranium.

Mr Adam demonstrated in laboratory experiments that such a deposit could
produce the chemical energy to generate some of the molecules in water
which produce amino acids and sugars - key building blocks of life -
when irradiated.

A deposit of a radioactive material called monazite would also release
soluble phosphate, another important ingredient for life, into the gaps
between sand grains - making it accessible to react in water.

Mr Adam told the New Scientist: "Amino acids, sugars and [soluble]
phosphate can all be produced simultaneously in a radioactive beach
environment."
Received on Tue 15 Jan 2008 08:59:47 PM PST