Finding alien life, be it microbes or Vulcans, would revolutionize our understanding of our place in the universe, not only because we would no longer be alone in the galaxy, but also because it may help us figure out the origins of life on Earth.
Panspermia is the theory that the seeds of life somehow came to our planet from another world. The idea is controversial at best—most biologists would tell you that it just pushes the problem back a step, because we still wouldn’t know what sparked life in the first place. And so far, there’s little reason to think life on other planets should be anything like what we see on Earth. … (Smithsonian)