The Seeds of Life - Exogenous Delivery of Organics to Earth Pascale Ehrenfreund1,2 1Space Policy Institute, Washington DC, USA 2 Leiden Institute of Chemistry, Leiden, NL

First stars 13.7 billion years WMAP CO detected Joyce 2002

Where do the organics come from ? Intrinsic Extraterrestrial influx (comets, meteorites) What environment on Earth ? (shallow basins, hydrothermal vents ?) What is coming from space ? (biomolecules as we know it, something else?)

Chemistry in space Shock waves Late heavy bombardment Violent catastrophicity ? Ehrenfreund et al. 2006

Organic compounds in Murchison Compound Class Concentration(ppm) CO2 106 CO 0.06 CH4 0.14 NH3 19 Aliphatic hydrocarbons 12-35 Aromatic hydrocarbons 15-28 Amino Acids 60 Monocarboxylic acids 332 Dicarboxylic acids 26 a-hydroxycarboxylic acids 14 Polyols (sugar-related) ~24 Basic N-heterocycles 0.05-0.5 Purines 1.2 Pyrimidines 0.06 Amines 8 Urea 25 Benzothiophenes 0.3 Alcohols 11 Aldehydes 11 Ketones 16 Sephton 2002

Dartois et al. 2005

Small bodies in our Solar System Their destiny….. Impact on planets Trapped by gravitational interaction Ejected out of the Solar System

The origin of life depends on a planet’s geology, hydrosphere and atmosphere National Geographic 1999

CARBON CHEMISTRY IN SPACE The carbon chemistry seems to follow common pathways throughout the Universe SPITZER Yan et al. 2005