Exobiology, also known as Astrobiology, refers to the study of the conditions necessary to support the independent development of extraterrestrial life. Direct proof has not yet been found of life anywhere in the universe other than on the Earth, but scientifically sound arguments have been proposed in support of such a possibility. The findings of modern astronomy suggest that a large number of stars could have planets orbiting them that provide conditions suitable for life, and laboratory experiments have demonstrated that many molecules necessary for life can be formed under conditions that may have been present on the Earth billions of years ago.
In trying to estimate the distribution of life in the universe, astronomers have developed the formula N = R*f*p*n*e*f*1*f*i*f*t*L--popularly known as the Drake equation after the American astronomer Frank Drake, who conducted the first radio search for extraterrestrial intelligence. In this formula, N, the number of civilizations capable of communicating across interstellar space, depends on the following: R*, the mean rate of star formation; fp, the fraction of stars with planetary systems; ne, the mean number of planets in each planetary system that are suitable for the origin and evolution of life; f1, the fraction of planets on which life can actually develop; fi, the fraction of life-bearing planets on which intelligent life can evolve; ft, the fraction of planets bearing intelligent life that can give rise to a civilization capable of interstellar communications; and L, the lifetime of a technical civilization.
Of these figures, only R* is well known from astrophysical studies.
Astrobiology is a newly emerging multidisciplinary field triggered by paradigm shifts resulting from discoveries regarding microbial extremophiles and evidence for possible microfossils in the Mars meteorite discovered on earth.
Astrobiology addresses fundamental questions of interest to all mankind: "Is life unique to Earth-or...