Some NASA scientists believe they are studying a fossil of life from Mars, reports Nancy Holland of CBS affiliate KHOU in Houston.
A pair of Martian meteorites contain features that resemble Earth bacteria, according to the same NASA researchers who three years ago claimed they had evidence of Â"primitive life on early Mars.Â"
The findings, made within the past six months, were from samples of a 1.3 billion-year-old meteorite that fell to Earth in 1911 near Nakhla, Egypt and a 165 million-year-old meteorite that fell near Shergotty, India in 1865.
Â"They have the same composition as fossil bacteria on Earth,Â" said NASA scientist David McKay.
The bacteria-like substance is so tiny, it would take a hundred of them to equal the width
of a human hair. But for McKay, theyÂ're huge.
Â"We're not counting on getting many converts,Â" McKay said. Â"All we ask, though, is that people keep an open mind.Â"
After McKay saw the bacteria-like features, he got a piece of the meteorite last year, looked inside, and is convinced it shows there was, at least at one time, life on Mars.
Back in 1997, McKay, 62, published similar findings and was almost immediately criticized by other scientists.
He says he was not deterred.
Â"WeÂ're gonna get beat up again. ThatÂ's okay,Â" McKay said.
McKay was one of the researchers who in August 1996 announced the discovery of tiny fossilized structures in crevices of a 4 billion-year-old Mars meteorite found in the Antarctic.
The meteorite was recovered in 1984.
McKay said some of the Nakhla features resembled Earth bacteria in a reproductive phase.
He also referred to the remains of what could have been a slimy Â"biofilmÂ" useful in snaring mineral nutrients.
He challenges doubting scientists to get their own piece of the rock and go to work.
McKay and the other scientists presenting their findings believe they can have a final answer about whether this is fossilized life within a year, using earthbound technology.
Â"If this proves out, we will have shown that life spanned almost the entire history of Mars, and presumably today,Â" McKay said. Â"Nothing has happened in the last 165 million years that would kill off life on Mars."
But an even better chance may come early next century, when a robotic mission brings back real Martian samples.
Then there may be more of an answer as to whether the universe could be filled with life, or if Earth is unique and we are very much alone.
Â"That is why (this analysis) is so important,Â" McKay said. Â"If what we see is borne out as signs of life, that pretty well predicts we will find life when we go there.Â"