The Universe’s Habitable Zone

Humans have a severe case of societal loneliness.  We send signals out into the void in the hopes that someone might answer, we launch spacecraft into the interstellar medium with a record of our civilization, we push the edges of our technology to seek evidence of long-extinct microbial and unicellular life on the Moon, Mars, asteroids, and other bodies in our solar system.  On a less evidential level, we seek clues, stories, and anecdotes that could enable us to believe that our species is not alone in the universe: points of light in the sky, a circle painted on a cave wall ten thousand years ago, unexplained happenings all over the world.