By Rossella Lorenzi, Discovery News
 Did
a Meteorite Seed Earth?
Italian researchers
claim to have found conclusive evidence that life on Earth arrived
from outer space.
Bruno D'Argenio,
a geologist working for the Italian National Research Council,
and Giuseppe Geraci, professor of molecular biology at Naples
University, identified and brought back to life extraterrestrial
microorganisms lodged inside 4.5 billion-year-old meteorites kept
at Naples' mineralogical museum.
"When
in contact with a physiological solution, they became visible
and began to move," D'Argenio said while presenting the finding
at the Italian Space Agency yesterday.
The bacteria,
called "cryms" (for crystal microbes) by the researchers,
remained dormant for billions of years and survived extreme ambient
conditions — a clear indication, according to the researchers,
that "life can exist everywhere in the solar system, though
in a quiescent state."
Once brought
back to life, the cryms were cloned by the researchers and their
DNA analyzed.
"Their
genetic code is unlike any known on Earth," said Giovanni
F. Bignami, scientific director of the Italian Space Agency.
In studying
the bacteria, the team found that they tend to gather in clusters.
The bugs are also killed easily with antibiotics.
Disputing
critics who suggested that the meteorites were contaminated with
terrestrial microorganisms, Bignami added that the bacteria came
back to life after the samples were sterilized at 950 degrees
Celsius and doused in alcohol.
The discovery,
if borne out, would strengthened the "panspermia" theory,
first suggested by chemist Svante Aarhenius in 1900. According
to this theory, outer space seeded Earth with primitive life forms
about 4 billion years ago. The theory was recently supported by
Noble Prize winner Francis Crick, as well as noted scientists
Fred Hoyle and Chandra Wickramasinghe.
"Life
would have formed as an initial seed in the protoplanetary nebula
from which all the planets originated. This microorganism can
be found ... in planetary bodies and in the meteors fallen to
Earth," said Bignami.
The Italian
researchers have also identified microorganisms identical to the
"cryms" found in the Naples meteorites in 50 samples
of billion-year-old terrestrial rocks from five continents.
"I'm
skeptical, very skeptical," biologist Martino Rizzotti of
Padua University told the daily newspaper La Stampa. "Those
bacteria seem to be too similar to the terrestrial ones. I can't
avoid thinking about possible contaminations."
Margherita
Hack, director of the Inter-University Regional Center for Astrophysics
and Cosmology in Trieste, is more positive. "It is very likely
that life is spread in universe. This is an interesting result,
but it requires more study to be completely accepted," she
said.
Today the
researchers present their findings at the Accademia dei Lincei
(Academy of the Lynxes) in Rome, a prestigious scholarly organization
that counts Galileo Galilei among its members.
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