Jupiter’s enigmatic moon Europa has long been thought to contain a huge ocean beneath its icy crust, but what is in that ocean and does it ever come to the surface? Since the Voyager and Galileo probes explored the Jovian system, its moons have presented an extraordinary and fascinating puzzle. The largest of the 67 [...]

This is the third of a three-part series that looks back at the 30-year history of the U.S. space shuttle program. Before the 1986 Challenger disaster made safety paramount and new constraints had been established, the shuttle could carry fueled upper-stage rockets to launch space probes, which embarked for planetary destinations. From low orbit to [...]

Edward Tufte is a man of many callings—data visualization guru, author of widely praised books, professor emeritus at Yale University, proprietor of the New York City gallery ET Modern. Add to the list collector of rare books—apparently Tufte tends a research library that contains works by some of the greatest thinkers of the past several [...]

Thanks to the much-heralded International Year of Astronomy, this much we know: Galileo used a telescope to observe the moon in 1609. But the inventor of the revolutionary resolutionary device remains unknown, and its early history is muddied by simultaneous discoveries and competing claims. In a paper posted to the online repository arXiv.org in August, [...]