Many years ago, Carl Sagan predicted there could be as many as 10,000 advanced extraterrestrial civilizations in our galaxy.
After nearly 60 years of searching without success, a growing list of scientists believe life on Earth only came about because of a lucky series of evolutionary accidents, a long list of improbable events that just happened to come together at the right time and will never be repeated. Is it possible they are right and we are all there is? Highly unlikely.
Earth is a typical rocky planet, in an average solar system, nestled in the spiral arm of an ordinary galaxy. All the events and elements that came together to build our world could happen almost everywhere throughout the galaxy and there should be nothing unusual about the evolution of life on this planet or any others.