Abu Rayhan al-Biruni, born a thousand years ago in Central Asia, calculated Earth's circumference with astounding accuracy and invented specific gravity, the measure of a substance's density compared to that of water. He rejected creationism, accepted that time has neither a beginning nor an end, and—5 centuries before Copernicus—argued that the sun might be the center of the solar system. Now, an influential U.S. scholar has proposed adding another laurel to that list: inferring the existence of America. Whereas some scholars think Biruni deserves credit for his continental prediction, others argue that his inference of unknown landmasses between Europe and Asia does not constitute a discovery.