Infrared Spectroscopy

Interstellar Space

The composition of the interstellar medium (the space between the stars) determines the composition of the objects which form from it such as stars and planets. The information provided by the study of atoms and molecules in interstellar space is crucial to our understanding of star formation and galactic evolution. The molecules which make up the interstellar medium have their identifying fingerprints primarily in the infrared. From their spectral lines, we can determine the temperature, density, luminosity, composition, magnetic fields, dynamics and detailed structure of interstellar regions of space. Infrared spectroscopy has led to the discovery of water, methane, carbon dioxide, formaldehyde, and carbon monoxide ices in interstellar space.

Interstellar molecules, such as water and ammonia and atoms such as oxygen and carbon are detected in the infrared in many parts of our galaxy. These molecules are found in the cool clouds of dust and gas within which new stars and planets are formed.

To see a list of the atoms and molecules identified in the interstellar medium click here.


Detection of oxygen in the dark molecular cloud SgrB2 (Keene, J. et al.)

Detection of carbon II in interstellar cirrus. Infrared spectral studies have shown that organic molecules are prevalent in many regions of the Universe.

Infrared studies have shown that the clouds of gas and dust between the stars contain complex organic molecules (the most basic 'building blocks' for life), some made of hundreds of carbon atoms. Recently, infrared spectral results from ISO have lead to the discovery of molecules which may show us the process of how complex organic molecules are formed in space.

Most of the heavier elements in the Universe are locked up in grains. Ice, seen at 3 microns, can coat some of these grains. Many of the grains are made of silicates which absorb and emit light at about 10 microns. So, near-infrared spectral studies can be used to detect these grains and discover the type of environment they are in. Infrared studies suggest that interstellar dust is an important source of water for all planets.


Infrared Spectroscopy Index | What is Spectroscopy? | Infrared Spectroscopy | Solar System | Interstellar Space | Star Forming Regions | Older Stars | Search For Life | Our Galaxy | Other Galaxies | Cosmology