Interstellar dust grains - small sub-micron-sized particles that pollute the space between the stars - play an important role in the chemistry of the galaxy as well as the star and planet formation process. We glean most information about dust composition in the interstellar medium from infrared spectroscopy. The vibration of molecules making up the dust cause light from a background star to be absorbed at very specific frequencies in the infrared portion of the spectrum. Dust originates in the outflows of old stars and is composed mainly of silicate minerals and carbon particles. In star formation regions, the silicate grains are covered with icy mantles. I will give an overview of the nature of these dust and ice components, with emphasis on our current understanding of the cosmic life cycle of these materials.
Pardon our Dust: Infrared Spectroscopy and Insterstellar Dust