--John
http://news.bbc.co.uk/hi/english/sci/tech/newsid_142000/142514.stm
Excerpt:
Thursday, July 30, 1998 Published at 19:50 GMT 20:50 UK
Sci/Tech
Creation could be left-handed
The answer to one of the deepest mysteries of life on Earth may be found in
deep space. Our science editor Dr David Whitehouse reports.
In 1848 Louis Pasteur discovered that some molecules can exist in two
mirror-image forms, termed right or left-handed. Curiously, in living things
the molecules tend to be one of these types and not a mixture of both.
Amino acids, the molecular building blocks of life are all left-handed where
as sugars, including deoxyribose an important component of DNA, are always
right handed.
By contrast, when these molecules are made in the laboratory equal numbers
of the right and left-handed versions are made.
Why life on the molecular level is like this is a mystery but now an
international team of astronomers may have discovered why life on planet
Earth is left-handed.
The astronomers believe that this left-hand bias began long before our Sun
was even born. At the time when our star was forming out of a vast cloud of
gas and dust more than five billion years ago.
....