In the six months since then, several studies have questioned their interpretations, and recently some in the media have used words from "doubt" to "death knell" to describe the Mars-life theory. In a speech today at the annual meeting of the American Association for the Advancement of Science in Seattle, however, a key researcher of the original project called dismissals of the claims entirely premature.
"It's time to pry the lid off the coffin, as our interpretations are still very much alive and doing well," said Dr. Christopher Romanek, now of the University of Georgia's Savannah River Ecology Laboratory in Aiken, S.C. "We had nine people working on the project for three years, and just since our press conference, researchers have had to formulate and design tests, perform experiments and interpret and publish the results in an amazingly short time frame.
"While these works are admirable on these grounds alone, they do not provide the information required to resolve the current contamination and formation temperature issues we face. And yet some of the press cling to reports that ring the `death knell' for potential Martian life. Nothing could be further from the truth."
Forthcoming papers soon to be published will show why the original Red Planet researchers are not red faced, Romanek said. At center stage of the controversy is a Martian meteorite, known as Alan Hills 84001, which was found in Antarctica about 13 years ago. It formed on Mars 4.5 billion years ago and, according to the researchers' paper published in Science last August, came in contact with liquid water between 3.6 billion and 4 billion years ago. From the water sprouted mineral deposits that bear a striking resemblance to fossilized bacteria.The researchers believe that about 16 million years ago, a comet or asteroid struck the Martian surface and blasted pieces of the rock into space, where they drifted for millions of years. The meteorite, found in Antarctica in 1984, fell to Earth about 13,000 years ago.
Two years earlier before the idea of Martian life ever crossed his mind, Romanek (and others) determined the Martian origin for mineral deposits or carbonate "globules" in the meteorite and determined the globules formed at a temperature capable of sustaining life. This information is crucial because extremely high formation temperatures rule out the possibility of life. Romanek has been convinced all along that the carbonate globules formed at low temperatures.
"In my opinion, it is clear the globules formed at low temperatures -- perhaps not as low as 0 to 80 degrees centigrade (as originally estimated), but surely not at the plus-or-minus 650 degrees centigrade, as suggested in one theory," said Romanek.
Romanek said that other papers, which focus on individual aspects of the NASA team's Science paper, fail to take into account all features in the carbonate globules collectively.
Romanek does not discount the possibility that future studies could provide a convincing alternative explanation for the formations found inside the meterorite, but for now, he believes the original conclusions of the study still offer the best explanations.
"We are completely open to new ideas and tests that will resolve the issues at hand, but these ideas need to be fully explored before informing the public," said Romanek. "I think we can resolve the issues of formation temperature and contamination soon, and we should do so with all expediency. If it turns out that either issue precludes a biologic origin for the features we found, we can move on to the many other exciting opportunities that our research has provided concerning processes on the surface of Mars."
(Editors/writers: While at the meeting of the American Association for the Advancement of Science in Seattle, Dr. Romanek will be staying at the Crowne Plaza in Seattle. The number there is 206/464-1980. If you leave a number, he will return your call. After Feb. 18, he can be reached at the Savannah River Ecology Lab, 804/725-8157.)