Abstract　 　　
　In 1960 the US radio astronomer Frank Drake started a search of radio signals from extraterrestrial technologically advanced civilizations using the Green Bank radio telescope. In 1961 the US National Science Foundation asked Drake to organize a meeting to discuss the possibility of finding other civilizations in our Galaxy. In preparation for that meeting, Drake wrote down the main factors that would need to be addressed to understand the odds of finding radio signals from extraterrestrial intelligent beings. The product of these factors is what is now known as the Drake Equation.

　 Advances in many fields of science since 1960 enable us today to use Drake's equation to make scientifically sound estimates of the number of intelligent civilizations expected to exist in our Galaxy. In this presentation I will show that using the best available data, the probability of finding intelligent life in other planets is still critically dependent of Drake's longevity parameter L: how long does a technological civilization survives to natural and people induced threats?