Molecules on a Space Odyssey

Abstract
Organic molecules have been shown to be ubiquitous in space and may be the source of the earliest biogenic molecules on Earth. As discussed in Ehrenfreund9s Perspective (p. 1123), the role of polycyclic aromatic hydrocarbons is particularly interesting. They are the most abundant organic molecules in space (about 20%), and recent experiments provide some clues about how these molecules might react to form ethers, alcohols, and other molecules that are a step closer to possible biogenic molecules. But many mysteries persist in the genesis and subsequent fate of these molecules.