Science fiction is the literature of our times, the fuel of our imaginations and the source of our favorite imaginary worlds. But what do we mean when we talk about “science fiction?” Here are some of ...

Re “Anthropology a Science? Statement Deepens a Rift” (news article, Dec. 10): From my perspective as editor in chief of American Anthropologist, the flagship journal of the American Anthropological ...

Astronomers are proposing a new, more quantitative definition of what makes a planet. The new definition looks more directly at the object's mass — but it would still leave Pluto out of the running.