Search for Life

"Human beings, as well as every other organism on the earth, are based on liquid water and organic molecules." (Carl Sagan)

The best wavelength region for locating extraterrestrial planets and the possibility of life there is the mid-infrared. Evidence of the conditions necessary for life can be found in the atmospheres of planets by detecting the existence of compounds such as water, carbon dioxide and ozone. For example, in our solar system the Earth is the only planet that has all three of these compounds in its infrared spectra.

ISO spectra of S106, Cirrus, NGC7027 and the Antennae galaxies with detection at 158 microns of CII.

Carbon chemistry is the basis of life as we know it, and has its beginnings in the interstellar medium. Infrared spectral studies have shown that carbon as well as complex organic molecules are abundant in many regions of space. The fact that these molecules are so abundant shows us that a very rich organic chemistry exists in the Universe. Results from infrared spectroscopy have shown that water is abundant in many regions of space. Water has been detected on many of the planets in our solar system and this water was likely present in the molecular cloud from which our solar system formed. Water is essential to life as we know it and has been detected in several areas where stars and possibly planets are forming.