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Science Blog ZINC PROJECTS

Odds of finding E.T. life low

Date: 17-Apr-08
Author: University of East Anglia

A mathematical model produced by a scientist from the University of East Anglia in U.K. suggests that the odds of finding new life on other Earth-like planets are low, given the time it has taken for beings such as humans to evolve and the remaining life span of Earth.

An artist's illustration showing an icy / rocky planet orbiting a dim star. Courtesy: NASA / ESA / G. Bacon (STScI)

Structurally complex and intelligent life evolved late on Earth and it has already been suggested that this process might be governed by a small number of very difficult evolutionary steps.

According to Prof. Andrew Watson a limit to evolution is the habitability of Earth, and any other Earth-like planets, which will end as the Sun brightens. Solar models predict that the brightness of the Sun is increasing, while temperature models suggest that because of this the future life span of Earth will be 'only' about another billion years, a short time compared to the four billion years since life first appeared on the planet.

Prof. Watson suggests the number of evolutionary steps needed to create intelligent life, in the case of humans, is four. These probably include the emergence of single-celled bacteria, complex cells, specialized cells allowing complex life forms, and intelligent life with an established language.

Each step is independent of the other and can only take place after the previous steps in the sequence have occurred.

Full story: Is there anybody out there?