“Our probable ancestors, Homo erectus and Homo habilis -now extinct- are classified as of the same genus (Homo) but of different species, although no one (at least lately) has attempted the appropriate experiments to see if crosses of them with us would produce fertile offspring.”

American astronomer and science communicator of the mid-to-late 20th century, Carl Sagan made complex cosmic concepts accessible to the public through his books and television series. He championed scientific skepticism and the search for extraterrestrial life, blending rigor with poetic clarity to inspire wonder about humanity’s place in the universe.