Three astronomers last week proposed expanding the official definition of a planet to encompass worlds orbiting stars other than our own, a nuance not currently included in the formal definition of ...

“Space” is one of those words that doesn’t really mean anything. It’s a concept that can’t really be put into a concise term. You can’t define space as boundary-less, because my half-empty Dr Pepper ...

The space shuttle program exists to build the space station. American taxpayers have spent $35 billion in space station hardware and many billions more for shuttle flights. But the orbiting facility ...