Polycyclic Aromatic Hydrocarbons

Using the Spitzer Space Telescope, astronomers have discovered organic molecules in galaxies only about a quarter of the age of our Milky Way. These polycyclic aromatic hydrocarbons (PAHs), composed of hydrogen and carbon, are pervasive in the Milky Way and play an important role in star and planet formation. These new observations suggest that since these molecules existed around 10 billion years ago, they may have represented the seeds of our own solar system. Spitzer observed these molecules in so-called starburst galaxies, where intense star-formation has occurred over a brief period of time. Since these galaxies usually contain large amounts of light-absorbing dust, they are invisble to optical telescopes. However, by observing in the near-infrared, Spitzer overcomes this limitation.