Occasionally Carl Sagan, the astronomist...
Occasionally Carl Sagan, the astronomist and space scientist at Cornell University, writes an article for common consumption in popular journals or Sunday magazines. He titled one article, "Is There Intelligent Life On Earth?" In this essay Sagan explains what an alien spaceship might reveal about our planet and ourselves. Visitors in an alien spaceship would have plenty of evidence and clues to surmise a great deal about our planet. They would be able to characterize our environment, detect definite signs of life and find manifestations of intelligent beings.