WASHINGTON - A Nasa scientist's claim that he found tiny fossils of alien life in the remnants of a meteorite has stirred both excitement and scepticism, and is being closely reviewed by 100 experts.
Richard Hoover's paper, along with pictures of the microscopic earthworm-like creatures, were published in the peer-reviewed Journal of Cosmology, which is available free online.
Hoover sliced open fragments of several types of carbonaceous chondrite meteorites, which can contain relatively high levels of water and organic materials, and looked inside with a powerful microscope.
He found bacteria-like creatures that he calls "indigenous fossils," which he believes originated beyond Earth and were not introduced here after the meteorites landed.
"He concludes these fossilized bacteria are not Earthly contaminants but are the fossilised remains of living organisms which lived in the parent bodies of these meteors, e.g. comets, moons, and other astral bodies," said the study.
"The implications are that life is everywhere, and that life on Earth may have come from other planets."
Studies that suggest alien microbes can be contained in meteorites are not new, and have drawn hefty debate over how such life could survive in space and how and where life may have originated in the universe.
The journal's editor in chief, Rudy Schild of the Centre for Astrophysics, Harvard-Smithsonian, said Hoover is a "highly respected scientist and astrobiologist with a prestigious record of accomplishment at Nasa."
"Given the controversial nature of his discovery, we have invited 100 experts and have issued a general invitation to over 5,000 scientists from the scientific community to review the paper and to offer their critical analysis," he said.
Those commentaries will be published this week.
A Nasa-funded study in December suggested that a previously unknown form of bacterium had been found deep in a California lake that could thrive on arsenic, adding a new element to what scientists have long considered the six building blocks of life.
That study drew plenty of criticism, particularly after Nasa touted the announcement as evidence of extraterrestrial life. Scientists are currently attempting to replicate those findings.