The Drake equation is one of those rare mathematical beasts that has leaked into the public consciousness. It estimates the number of extraterrestrial civilisations that we might be able to detect today or in the near future.

The equation was devised by Frank Drake at the University of California, Santa Cruz in 1960. He attempted to quantify the number by asking what fraction of stars have planets, what fraction of these might be habitable, then the fraction of these on which life actually evolves and the fraction of these on which life becomes intelligent and so on.

Many of these numbers are little more than wild guesses. For example, the number of ET civilisations we can detect now is hugely sensitive to the fraction that destroy themselves with their own technology, through nuclear war for example. Obviously we have no way of knowing this figure.

Nevertheless, many scientists have attempted to come up with a figure with estimates ranging from a handful of ET civilisations to tens of thousands of them.

Really? Then how does one explain the UFOs flying around in Earth's skies right before our eyes? To read the rest of the article, click here.