for 50 years now, seti, that's, seti, the search for extraterrestrial intelligence, has scoured the galaxy listening for signals of alien civilizations. so far none have been detected but scientists believe they already know plenty about alien life and the reasons why it would resemble life on earth. what does the evolution of life on our planet tell us about the likelihood that alien civilizations exist? in the second of a two-part series, we will ask one of the originators of the dark matter theory, dr. joel primack and nancy ellen abrahams. if. for such a small if i live to a hundred. if social security isn't enough. if my heart gets broken. if she says yes. we believe if should never hold you back. if should be managed with a plan that builds on what you already have. together we can create a personal safety net, a launching pad, for all those brilliant ifs in the middle of life. you can call on our expertise and get guarantees for the if in life. after all, we're metlife. >>> this is the second session with two extraordinary people, nancy abrahams wosay lawyer, a song writer, a spouse