Intelligent ET life probably not likely, according to English study

William Atkins
Saturday, 12 April 2008 21:56

Science - Space

His conclusions are based on a mathematical model, which has been enhanced from older models, that describes the evolution of intelligent life, whether it is here on Earth or elsewhere out there in the Universe, based on a limited number of discrete steps.

Specifically, the model assumes that the evolution of intelligent life is limited directly by the evolution of its star.

As a star ends it life, it becomes increasingly hotter, which in effect ends the life of intelligent life (unless of course they have left their home planet for other destinations).

In the case of Earth’s Sun, it is now about one-fourth brighter than when the Earth first formed about 4.5 billion years ago.

Scientists now contend that within about one billion years the Sun will increase the average temperature on Earth to levels that will make the planet [un]inhabitable for humans and most other life forms.

Thus, Watson’s four discrete steps of evolution of intelligent life, based on Earth’s history is:

(1) emergence of single-celled life (about four billion years ago);
(2) multi-cellular life forms develop (about 2.5 billion years ago);
(3) specialized cells develop that allow complex life forms to develop (about 1.5 billion years ago); and
(4) intelligent life (in our case, human-like beings) with an established language (roughly about five hundred million years ago).

According to Watson, the chance that intelligent life is able to develop into step four is based on the probability that each earlier step is able to proceed.

Watson states that the probability of each step occurring is ten percent (0.1) or less. Thus, the total probability that intelligent life will emerge in step four is less than 0.01 percent (0.1 x 0.1 x 0.1 x0.1 = 0.0001 or 0.01%) over an approximate four-billion-year period.

His conclusion is "… a reasonable first approximation for what is, after all, a very idealized sort of model, deliberately simplified enough that the math can be solved analytically." [MSBNC: “Study dampens hopes of finding E.T. Smart aliens might not even live on Earthlike planets”]

Watson continues: " ... only on those rare planets on which complex creatures happen to evolve can there exist observers who ask questions about evolution and care about the answers."
 
[Author's note: Good catch by reader: the planet would be "UNinhabitable for humans..." Correction made to text.]