On Thursday, Dec. 2, Rosie Redfield sat down to read a new paper called, “A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus.” Despite its innocuous title, the paper had great ambitions. Every living thing that scientists have ever studied uses phosphorus to build the backbone of its DNA. In the new paper, NASA-funded scientists described a microbe that could use arsenic instead. If the authors of the paper were right, we would have to expand our notions of what forms life can take.
Redfield, a microbiology professor at the University of British Columbia, had been hearing rumors about the papers for days beforehand. On Monday, NASA released a Sphinxlike press release: “NASA will hold a news conference at 2 p.m. EST on Thursday, Dec. 2, to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life.” Like a virulent strain of bacteria, speculation exploded over the next three days. “Did NASA Discover Life on One of Saturn’s Moons?” asked Gawker, a Web site that does not often ask questions about astrobiology.