Astrobiology, the science in search of a subject, has major hurdles to overcome in its quest to explain everything from hydrogen to high technology. Despite being one of the most active interdisciplinary research projects around the world (see 01/07/2005 entry), a leading researcher this week conceded that several promising leads of the past are now considered unlikely. Because the biochemicals we know (proteins and nucleic acids) are so advanced and improbable under prebiotic conditions, attempts to generate them or build living systems based on them have proved fruitless. Astrobiologists are having to imagine simpler, hypothetical precursor molecules as stepping stones. If square one was the Miller experiment in the 1950s, this puts them behind square one.

During the Q&A, this reporter mentioned that Benner (11/05/2004) had suggested a desert environment was necessary to stabilize ribose, yet Russell (12/03/2004) countered that was the worst environment because of the radiation, which her experiments seemed to confirm. What was her take on these mutually exclusive scenarios? All she could offer were vague suggestions that comets or meteorites might deliver simpler materials to concentrated areas somehow, perhaps in environments alternating hot and cold between impacts. Most of her answer discussed problems #4, 5 and 6, above.