The frozen chunk of stone and metal was recovered in the Yukon Territory after eyewitnesses saw its dramatic breakup in the sky. Inside the so-called Tagish Lake meteorite, frozen and well preserved, researchers have now found what they call organic hydrocarbon globules.

Similar bubble-like structures have previously been created in laboratories at NASA's Ames Research Center, under conditions designed to simulate how Nature might have cooked up the first life on Earth.

The new finding, accomplished after months of investigation with electron microscopes, does not mean life exists in space rocks. The hydrocarbon globules are seen as the sort of thing which, once delivered Earth, could have helped jumpstart life.

"While not of biological origin themselves, these globules would have served very well to protect and nurture primitive organisms on Earth," said Michael Zolensky of NASA's Johnson Space Center in Houston. "They would have been ready-made homes for early life forms."

The meteorite crashed through Earth's atmosphere over the Yukon Territory of Canada on Jan. 18, 2000, breaking into many pieces. Parts of it were collected in protective kitchen Baggies and kept frozen and pristine.

"If, as we suspect, this type of meteorite has been falling onto Earth throughout its entire history, then the Earth was provided with these hydrocarbon globules at the same time life was first forming here," said Zolensky, who was part of an international team of scientists from several institutions that conducted the study.

The work was led by Keiko Nakamura of Kobe University in Japan. The results were published this week in the International Journal of Astrobiology.

Other research by various groups has provided some evidence to support a bolder speculation involving space rocks, that they actually might have delivered life itself to our planet. One study showed that life from Mars, if it ever existed, could have been transported to Earth inside a rock, thus making us all descendents of early Martians.

The Tagish Lake meteorite, however, promises only a humble home for life. But the discovery has possible implications for other planets and even moons.

Similar meteorites most likely have, through time, landed on Europa and other moons of Jupiter, places where astrobiologists suspect conditions might be hospitable to life, particularly within a liquid ocean that seems to exist beneath Europa's frozen exterior.

"It is interesting to speculate about the presence of these organics in the ocean we believe may be present under the ice cap of this moon," Zolensky said.

Many scientists have pushed for a mission to Europa to search for possible signs of life, but NASA has not committed to one.

• Eyewitness Accounts of the Yukon Fireball
• Initial Discovery of the Tagish Lake Meteorite
• Mimicking Primitive Conditions in the Lab