"In his book "Five Billion Years of Solitude: the Search for Life Among the Stars", Lee Billings describes the quest for answers to this profound question". (Lissauer, 2014, p. 2)
"Astrobiology" is a field studies the interdisciplinary scientific several forms of direct searches for life beyond our planet. (Lissauer, 2014)
"If life spreads between planets, inhabited worlds should clump in space like colonies of bacteria on a Petri dish. Otherwise, Lin says, its signature would be seen on just a few, randomly scattered planets". (Sokol, 2015, p. 4)
Finally, it's time to know our friends in the universe.