Larger Molecules in Space

    For many people one of the most interesting question ever asked is "is there life out there?". This simple question is one mankind has tried to answer for centuries and although many believe that there is extraterrestrial life we still lack the proof. The interstellar medium does suggest that it is possible for life to exist elsewhere in the universe. 

    Molecules have been found in the interstellar medium by sweeping the radio frequencies of the electromagnetic spectrum. Many simple molecules such as CO, CN and OH have been detected, but to many people it is the discovery of complex organic molecules, such as formaldehyde (H2CO) and methanol (CH3OH), which are of the most interest. Amino acids are the basic building blocks of life and all the reagents which are used in a laboratory to synthesize such molecules are available in the interstellar medium.

    Most of these molecules are formed via a sequence of two-body, ion-molecule processes in the gas phase, using interstellar grains as a catalyst. The majority of molecules found in the interstellar medium are found in giant molecular clouds, where the density tends to be higher and the probability of a collision is appreciably higher. Another reason that molecule formation is favoured in large clouds is that in the core of these clouds is protected from ultraviolet radiation by the atoms, ion around the edges.


Complexity            Inorganic                                                               Organic                                               


 Diatomic                HD                           deuterized hydrogen               CN                           cyanogen radical

                                OH                           hydroxyl radical                       CO                           carbon monoxide

                                SiO                           silicon monoxide                      CS                            carbon monosulfide

                                SO                            sulfur monoxide                       C2                            carbon

                                NO                           nitric oxide             


Triatomic                H2O                         water                                      CCH                         ethynyl radical

                                HDO                        heavy water                          HCN                        hydrogen cyanide

                                H2S                          hydrogen sulfide                 HCO                        formyl radical         

                                SO2                          sulfur dioxide                        DCN                        deuterium cyanide


4  Atomic             NH3                         ammonia                              H2CO                    formaldehyde

                                                                                                                HNCO                    hydrocyanic acid

                                                                                                                H2CS                      thioformaldehyde

                                                                                                                HC2H                     acetylene


5  Atomic                                                                                             CH4                        methane

                                                                                                                H2HCN                  cyanamide

                                                                                                                HCOOH                 formic acid

                                                                                                                HC3N                    cyanoacetylene


6 - Atomic                                                                                              CH3OH                  methyl alcohol

                                                                                                                HCONH2               formamide


8  Atomic                                                                                            HCOOCH3             methyl formate


9  Atomic                                                                                             CH3CH2OH           ethyl alcohol


11  Atomic                                                                                            HC9N                     cyanotetraacetylene