Detecting Conditions Favorable to Life on Other Planets
While some may want to believe that detecting planets, with environments that are hospitable to life, is something beyond our technological capacities, NASA would disagree. The Terrestrial Planet Finder evidences a belief that not only can conditions favorable to life be detected, but the effort to do so is also worthwhile. This from the linked article:
"The search for habitable planets and life is founded upon the premise that the effects of even the most basic forms of life on a planet are global, and that evidence for life, or biosignatures, from the planet's atmosphere or surface will be recognizable in the spectrum of the planet's light. Observations across as broad a wavelength range as possible are needed to fully characterize a planet's habitability and to detect signs of life.
Direct imaging detection and spectroscopic characterization of nearby Earthlike planets will be undertaken by the Terrestrial Planet Finder missions. The TPF Coronagraph (TPF-C), planned for launch in 2014, will operate at visible wavelengths. It will suppress the light of the central star to unprecedented levels, allowing it to search for terrestrial planets in ~150 nearby planetary systems. TPF-C will be followed about five years later by the TPF Interferometer (TPF-I). TPF-I will operate in the mid-IR and will survey a larger volume of our solar neighborhood, searching for terrestrial planets around as many as 500 nearby stars."
While plans for future missions are already underway NASA is not without existing data to support its views. This link discusses data about planets already discovered. From that article:
"Astronomers have captured enough light from two planets far beyond our own solar system to reveal details of their chemical make-up, marking a new phase in the search for extraterrestrial life.
By analysing the faint glow of one of these alien worlds they have found tentative evidence that suggests the presence of chemicals which play a role in one theory of how life began on Earth.
The chemicals, polycyclic aromatic hydrocarbons, may have helped the formation of RNA, the ancestral genetic material of DNA, the building-blocks of life on our own planet.
Although this planet seems to lack water and is at a searing 800 C - which is thought to be much too hot for life - three teams announce today they have successfully carried out the feat on this and one other alien world, marking a breakthrough in the development of techniques capable of scouring the cosmos for signs of life."
NASA efforts offer opportunities to gather data that either confirm or caste doubt on the belief that life exists elsewhere in the cosmos.