Endangered; April 1998; Scientific American Magazine; by Gibbs; 2 Page(s)

Eighteen months after David S. McKay and his colleagues at the National Aeronautics and Space Administration Johnson Space Center raised eyebrows with their claim that a potato-shaped meteorite, dubbed ALH84001, contained microscopic fossils of ancient life from Mars, the team has made few converts. "There was a very quick division into a few groups that believed it and many more that didn¿t," recalls Allan H. Treiman of the Lunar and Planetary Institute in Houston. Since then, Treiman says, "I haven¿t seen anybody change their mind."

While McKay¿s team has spent much of the intervening months searching for bacteria on Earth that at least proves that the creatures they hypothesize are not impossible, its critics have published dozens of new observations they believe make that theory increasingly improbable, compared with nonbiological explanations for the meteorite¿s puzzling features.