How common are the conditions required for life?

Astrobiology, also known as xenobiology or exobiology is a speculative field within biology concerned with extraterrestrial life.

Where are the data?Edit


Terrestrial Planet Finder.

Astrobiology is an idea in search of data. Many scientists expect that life is common, probably having come into existence on millions of planets. However, astrobiology is a speculative field within biology; nobody has evidence for extraterrestrial life. Astrobiology includes the concept of artificial life, since any life form with human-like intelligence could conceivably create artificial life in a laboratory. Such artificial life might be more suitable than a biological organism for interstellar travel. While currently funded efforts in astrobiology focus on planetary exploration and attempts to detect planets with Earth-like atmospheres, it has been suggested that we should also look closely at Earth for signs that alien artificial life is already here.


Possible landing site at Eos Chasma

Possible dataEdit

Probably the strongest claim that we have data in hand comes from study of Mars meteorite ALH84001[1]. This is the Martian rock first reported in 1996 to possibly contain evidence of fossilized microbial life. It has been estimated that ALH84001 was knocked off of the surface of Mars 20 million years ago during the formation of an impact crater. In 2005 it was reported by Vicky Hamilton of the University of Hawaii that the mineral composition of ALH84001 matches one known location on Mars, Eos Chasma, part of the Valles Marineris canyon system. It has been suggested that this might be a good target for a mission to Mars that would seek signs of past life.


  • The Drake Equation
  • can human like intelligence evolve under water?
  • can comets incubate life and seed it to planets?


  1. ^  For example, see: "Magnetofossils from Ancient Mars: a Robust Biosignature in the Martian Meteorite ALH84001"

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