The Drake Equation

A few weeks ago I coincidently watched two programmes featuring an equation dreamed up by an American Astronomer - Frank Drake. This equation supposedly calculates the liklihood of intelligent extra terrestrial life in the Milky Way with which communication might be possible from Earth.

The first programme I watched was fiction, and so I passed it off as a leap of imagination and let it lie. Then a few days later it reappeared in a BBC4 programme entitled 'The Seach for Life: The Drake Equation'. In this documentary the Drake Equation was taken apart and explained in its constituent parts. Here my suspicions and issues with it grew as the leaps of faith allowed by fiction was seemingly being entertained by the scientific community.

Before I delve into this 'revolutionary' equation, I feel I must introduce it properly;

(stolen from Wikipedia)

The full equation is explained properly here, and I shan't waste time here going into it.


This equation I have no problem with, it seems to fulfil all sensible areas of calculation in order to estimate the liklihood of little green men.

In this BBC production, Drake inputs various numbers into his infamous equation to create the all-important estimate. I'm sure anyone ignorant of this knowloedge previously is fairly interested to hear the prediction. It is 10.

Ten instances in our galaxy that would likely have developed intelligent enough life to create the desire to communicate with other beings. Again, I shan't delve into complicating issues such as of dying civilisations, changing technology or sheer bad luck, as it is the arrogance with which Drake ploughs on with his prediction that I take offence to.

The first two numbers input by Drake are perfectly acceptable (despite the recent, more accurate estimates, but for the purpose of argument, they are innocuous enough) - 10 stars formed per year and half of these stars will be orbited by planets. Unfortunately it is here that his equations seems to begin to leap into the abyss of guesswork.

http://www.spacetelescope.org/images/heic0411a/

Next comes potential development of life on the planets formed. In each solar system he predicts that 2 planets will be capable of this feat. He based this guess on our solar system, which - as far as we currently know for sure - only houses one planet with life one - and so, suggestably, only one capable of nuturing life. This leads onto the next part - actual development of life. Here, Drake predicted a 100% sucess rate. How on Earth (and the other life-sustaining planet in this solar system) does this one work? We have proof for one instance of life in the entire universe, and this is planet Earth. How can he predict 2 planets having the correct atmosphere to house life when the practise of modern astronomy is still uncertain of life orbiting our Sun?

So we now have life on 2 planets in this hypothetical solar system. Supposedly 1% of this will evolve to be intelligent! Of the billions of species of life on Earth, only one has managed to evolve to fit the criteria of 'intelligent', yet the bold Drake chose to go with his one-in-a-hundred theory.

The final input I take issue with is the ability to communicate - the penultimate number. Again, 1% is utilised. Again, Drake has ignored the one study of life in the universe we have. He predicts that 1% of the intelligent life evolved will develop the ability to communicate with other planets when the evidence we hold tells us that the one instance of intelligent life has developed the ability and desire to communicate.

http://www.jpl.nasa.gov/news/profiles.cfm?profile=560

The equation has since been readjusted by other scholars and new predictions have been created. But there is a distinct lack of impirical evidence - as can be expected with this line of exploration - to go along with the painfully arrogant guesses that Drake originally made.

I utterly believe that there is life out there, somewhere in the vastness of the universe, so please do not take this ranting piece as an attack on the search of extra terrestrial life - although I am not entirely decided on the safety of communication and contact with alien beings, despite the fascination behind it.

This blog's been a bit of a change of topic from the usual, so I hope it's not been too boring to trawl through. It's current 3am and I have a lecture to be attending in 6 hours time, so it's good to see me putting my nighttime to good use.