posted on Apr, 11 2008 @ 10:40 AM
In a recent paper published in the journal Astrobiology, Professor Andrew Watson of the University of East Anglia describes an
improved mathematical model for the evolution of intelligent life as the result of a small number of discrete steps.
According to Professor Watson, there evolution of intelligence is quite likely to be a rare phenomenon in our Galaxy.
He concludes this based on the additive probability of each of the steps occurring during the 4 billion years available for evolution. He feels these
steps must occur in the proper sequence, also, and that they may irreversibly change the biosphere of the planet. For example, the evolution of plant
life ended up changing the concentration of oxygen in our atmosphere.
The habitability of Earth is defined partly by the length of time that the sun will remain stable. As the Sun progresses, it will increase its
temperature about 25%.
So if you calculate the additive probability of each major step that allowed the evolution of intelligence, according to Dr Watson, that ends up with
a probability of less than 0.01% during the 4 billion years available.
Though a billion years is a long time, it's only a fraction of the time the planet exists, which makes the lifespan of an intelligent species
Though there are some competing opinions, notably that of Seth Shostak, this new estimate puts a bit of a damper on the notions of the prevalence of
intelligent life in our Galaxy.
[edit on 11-4-2008 by Badge01]