Are there any extra terrestrials out there?

April 19th, 2008 - 5:30 pm ICT by admin  


London, April 19 (IANS) Is there anybody out there? The odds of finding life on other planets are low, given the time it has taken for earthlings to evolve and the ebbing lifespan of our planet. Complex life is separated from the simplest forms by several very unlikely steps and therefore will be much less common. Intelligence is one step further, so it is still much less common,” Andrew Watson of University of Anglia said Saturday.

He said the number of such evolutionary steps needed to create intelligent life is four. They include the emergence of single-celled bacteria, complex cells, specialized cells allowing complex life forms, and intelligent life with an established language.

A limit to evolution is the habitability of Earth. Solar models predict that the brightness of the sun is increasing. It will limit the planet’s life span to another billion years, compared to the four billion years since life appeared on it, reports Sciencedaily.

“At present, Earth is the only example of a planet with life. If we learned the planet would be habitable for a set period and that we had evolved early in this period, then even with a sample of one, we’d suspect that evolution from simple to complex and intelligent life was quite likely to occur,” he said.

“By contrast, we now believe that we evolved late in the habitable period, and this suggests that our evolution is rather unlikely. In fact, the timing of events is consistent with it being very rare indeed.”

His model has been published in Astrobiology.

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