The Empty Universe vs. Zillions of Aliens DebateS

It's a big, dumb, empty universe, according to a new formula that estimates our chances of meeting non-human intelligent life. The odds have been estimated before, most famously by the Drake Equation, but now a British scientist has tried to throw a wet blanket over exobiologists and scifi writers by claiming that intelligent life is vanishingly rare. Here's why he's wrong.

The Drake Equation is a series of decreasing fractional probabilities that end up estimating the chance that there are other intelligent civilizations somewhere in the universe. The enormous scale of the universe virtually guarantees that a decent probability will come out of that equation. Professor Andrew Watson of the University of East Anglia has recalculated the odds, factoring in the age of the Earth. He claims that Earth is in the latter stages of its life as a planet, meaning that it took a long time for intelligent life to develop here. Therefore, such life doesn't happen easily, and must be quite rare.

I say bollocks. Watson fails to take into account a number of factors. For one thing, not every solar system follows the same life pattern as ours. Other planets may have far longer habitable periods than Earth, increasing the odds of intelligent life developing there. He also fails to consider that different environments could lead to very different evolutionary rates.

In the end, it comes back to the scale of the universe (how many galaxies can you spot in the Hubble image above?). It doesn't matter how improbable the odds of intelligent life evolving are. We know for a fact it happened once. It is almost inconceivable to think that among the unfathomable numbers of stars and planets scattered across the universe, it happened only once. Photo by: ESA and NASA.

Is there anybody out there? [University of East Anglia]