(Astronomy) Pondering Extraterrestrial Life (1/5)
Extraterrestrial life is defined as life that does not originate from Earth. It is unknown whether any such life exists, and all discussion of it must be regarded as highly speculative. Various claims have been made for evidence of its existence, such as those listed in a 2006 New Scientist article. However, the mainstream scientific community regards all such claims as unconvincing. A less direct argument for extraterrestrial life relies on the vast size of the observable universe. According to this argument, endorsed by Carl Sagan, it would be improbable for life not to exist somewhere other than Earth. The theorization of extraterrestrial life is known as astrobiology, exobiology, or xenobiology. One possibility is that life has emerged independently at many places throughout the universe. Another possibility is panspermia or exogenesis, in which life would have spread between habitable planets. These two hypotheses are not necessarily mutually exclusive. Possible forms of extraterrestrial life range from simple bacteria-like organisms to sapient beings far more advanced than humans. Suggested locations on which life might have developed, or which might continue to host life today, include the planets Venus and Mars, moons of Jupiter and Saturn (eg Europa, Enceladus and Titan) and Gliese 581 c and d, recently discovered to be near Earth-mass extrasolar planets apparently located in their star’s habitable zone, and with the potential to have liquid water. Beliefs that …
Tags: astrobiology, Astronomy, Carl Sagan, Earth Mass, Enceladus, Exobiology, Extrasolar Planets, extraterrestrial, extraterrestrial life, Gliese 581 C, Habitable Planets, Habitable Zone, life, Life Today, Liquid Water, Mars Moons, Moons Of Jupiter, New Scientist, Observable Universe, Panspermia, Pondering, Scientist Article, Venus And Mars, Xenobiology
