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Alien life claim ignites scientific debate

A NASA researcher's claim to have discovered evidence of bacterial life not native to Earth has triggered a predictable flurry of commentary within scientific circles. The paper, published by Richard B. Hoover of NASA's Marshall Space Flight Center, reports finding "microfossils of cyanobacteria" that he says arrived on Earth by hitching a ride on a rare category of meteorites.

Needless to say, this claim will get subjected to intense scrutiny in coming days and weeks. And as Nature notes on its website today, others have offered similar claims - including this paper published in 1996 - and none have yet found general acceptance. Still, the debate has again been joined since Hoover's article went viral over the weekend. The Journal of Cosmology, where Hoover's article appeared, is now sharing some of the reactions from experts invited to weigh in on his piece.

Here's a sample of the commentary:

Rhawn Joseph, author of Life on Earth, Came From Other Planets:
"there is absolutely no evidence life began on Earth. In fact, there is considerable evidence life could have never begun on this planet...Earth is not the center of the biological universe....Certainly the mounting evidence demonstrating life came from other worlds will be rejected by those who believe Earth is a very special, precious little planet, with magical life-generating powers, as described in Genesis, chapter 1 of the Bible. And of course these conclusions will be disputed by the "torches and pitchforks" crowd who come lumbering forth grunting in fear, condemning and seeking to destroy what they don't understand."

Michael H. Engel, School of Geology & Geophysics, University of Oklahoma:
"There are legitimate reasons to initially be skeptical of these findings, not the least of which being the antiquity of these observed falls...The search for extraterrestrial life is one of the fundamental quests of all mankind. Given the enormity of the galaxies that comprise our universe, we remain convinced of the certainty that life exists elsewhere. The paradox is that when faced with the actual possibility of evidence for extraterrestrial life, we quite often feel more compelled to ignore it or refute it rather than embrace it. Perhaps this has something to do with our inherent fear of the unknown. With respect to these new findings, I encourage people to keep an open mind when forming an opinion as to the significance of this work. "

Cody Youngbull, Arizona State University's Biodesign Institute:
"Online peer review is a wonderful contribution to science because it allows for wild ideas to be shared where otherwise they would be forced to exposition in a flood of conference proceedings....Based on similar past claims of the past 50 years, what will likely follow is that healthily skeptical experts will dream up reasonable mechanisms for these formations. Regardless, let us recognize Dr. Hoover's brave devotion to such a powder keg of an observation."

Harrison Schmidt, University of Wisconsin-Madison College of Engineering, Former United States Senator, Apollo 17 Astronaut:
"I will let others more expert than I comment on Dr. Hoover's evidence of life forms in CI1 meteorites. I only wonder why many do not seem to want life to have originated independently on Earth? It is the one place we know best and have the best evidence that conditions existed prior to about 3.5 billion years for complex molecules and then replicating life forms to have formed. Water, carbon, nitrogen, phosphorous, impact and/or lightning energy, clay and/or sulfide templates, and time were available from about 4.5 billion years ago. We just have to figure out how it all happened." M.A. Line, School of Agricultural Science, University of Tasmania:
As Carl Sagan said, an extraordinary claim demands extraordinary evidence. I believe the extraordinary evidence is in this paper, but it could be better presented...A couple of points that arise from this investigation, are the implications of the discovery of cyanobacteria in meteoritic material of extra-terrestrial origin. Firstly it raises the possibility of a deep (longer than the time available on Earth) evolutionary history for aerobic metabolism, a contention that is strongly supported by recent phylogenetic studies. Secondly, since cyanobacteria comprise just a branch of the Domain Bacteria, their existence in meteoritic material means that the three domains of life (Bacteria, Archaea and Eukaryota) evolved and separated prior to their colonization of Earth...It would also mean that life on Earth did not originate from a single cell; representatives of all three domains must have arrived from space."

Patrick Godon,Astronomy & Astrophysics, Villanova University:
"While the evidence clearly indicates that the meteorites was eons ago populated with bacterial life, whether the meteorites are of actual extra-terrestrial origin might (be) debatable...A number of biominerals and organic chemicals (that are interpreted as biomarkers when found in Earth rocks) have been detected in CI1 carbonaceous meteorite. These include weak biomarkers including some that are produced in nature by biological processes but can also be fomed by catalyzed chemical reactions. However, the CI1 meteorites also contain a host of strong biomarkers for which there are no known abiotic production mechanisms."

You can access the full text of these and other reactions to Hoover's article - which be published on the Journal of Cosmology website through March 10 - by clicking here.