EXTRATERRESTRIAL bacteria have been found alive and well inside a
meteorite—or so claim two researchers at the University of Naples. Other
geologists say the Italians have probably found little earthlings.
Geologist Bruno D’Argenio and molecular biologist Giuseppe Geraci say they
discovered bacteria wedged inside the crystal structure of minerals in the
meteorite. The bacteria started growing when a bit of the rock was placed in a
culture medium. The researchers claim the bacteria must be extraterrestrial
because they survived when the sample was sterilised at high temperatures and
washed with alcohol.
Bacteria that arrive from space should be able to survive high temperatures,
they argue. But they also say the bacteria are susceptible to antibiotics, which
suggests they are similar to Earth bugs. David Wynn-Williams of the British
Antarctic Survey says Earth bacteria could easily have invaded the rock, to
depths that were not affected by the heat or alcohol. He and his colleagues grew
bacteria found inside the crystals of a Martian meteorite last year—but
they looked exactly like Antarctic soil bacteria.
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The Italian pair also claim the bacteria’s DNA is unlike any on Earth. But
D’Argenio will only reveal their full findings at a meeting on extraterrestrial
biology in Frascati, Italy, later this month.
Scientists are still debating whether structures in Martian meteorites are
fossil bacteria
(see “Mars Attracts”).
“I believe we will find evidence of life elsewhere,”
says Wynn-Williams. “But it almost requires keeping a meteorite sterile from the
moment it lands.”