How would scientists tell the world if they found evidence for alien life? According to SETI, the probability of finding alien life somewhere in the Milky Way is high, based on a number of studies showing that our galaxy contains countless Earth-like planets that orbit sun-like stars. Neil deGrasse Tyson thinks we are probably not alone given the fact how many stars there are in the galaxy not to mention the entire universe. Other prominent scientists also think we will most likely find compelling evidence for extraterrestrial life relatively soon. Undoubtedly evidence for alien life would be the biggest discovery in human history.