Penelope Boston bypasses NASA's elliptical PR and arrives at a portentous conclusion: there's probably life on Mars, and we should be trying to determine where it is and where it originated.

Peter Watts offers some intriguing thoughts on Candidatus Desulforudis audaxviator, exobiology and immortality.

Bold traveler's journey toward the center of the Earth

The first ecosystem ever found having only a single biological species has been discovered 2.8 kilometers (1.74 miles) beneath the surface of the earth in the Mponeng gold mine near Johannesburg, South Africa. There the rod-shaped bacterium Desulforudis audaxviator exists in complete isolation, total darkness, a lack of oxygen, and 60-degree-Celsius heat (140 degrees Fahrenheit).