Probability One - Tapa blanda

'The argument is wholly convincing and Aczel presents it in absorbing style, taking us through science and mathematics with commendable lucidity.' FINANCIAL TIMES In a universe infinitely large, what is the probability of intelligent life on another planet? Sounds like a trick question, but for anyone versed in cosmology and statistics, the answer is 1; that is, there must be life on at least one other planet in the universe. This is Amir Aczel's theorem. But, as physicist Enrico Fermi once asked, if that's true, where is everyone? Aczel tackles that paradox after he goes through the statistical calculations for the probability of intelligent life, considering factors such as how many stars are in a galaxy, how many of those stars might be hospitable, how many might have planets, and how many planets might have environments suitable to support life as we know it (or as we don't). Aczel also provides an overview of the relevant developments in astronomy and biology, laying the groundwork to show that the universe's chemistry must add up to life. Whether life was spread through the universe by chunks of debris like ALH84001--the enigmatic meteorite from Mars that contained tantalising hints of the possibility of life--or arose independently, Aczel is sure it is out there. After teasing readers with scientific history, Probability 1 delivers on its promise to prove Aczel's conjecture through a clearly explained application of known statistical theory to the chaos of the universe.' - Therese Littleton, AMAZON.COM

At one level, PROBABILITY ONE surveys recent findings about the existence of planets orbiting other sun-like stars, such as 51 Pegasi, discovered in 1995, Tau Bootis and others. Amir Aczel asks What is life? as well as: What is intelligent life? He examines the theories about how life evolved on earth from basic molecules, such as ammonia, into more complex organic compounds leading to DNA. The existence of similar molecules on other planets in our solar systems, as well as in meteorites that land on earth every year, are used in an argument for the evolution of such compounds - the building blocks of life - outside Earth. However, Aczel approaches his subject in a completely novel way, using the full power of modern probability theory. The laws of large numbers applied to the immense size of the known universe with its billions of galaxies, each containing many billions of stars, are used to argue the probability that there is life elsewhere. Aczel weaves the probability arguments seamlessly throughout a fascinating - and accessible - book.