Why build a space elevator? "The space elevator will reduce the cost of getting from Earth to space. It will also allow us to take very large payloads into space very easily, very safely.

We spoke with theoretical physicist Brian Greene about Einstein's theory of space-time. Many scientists believe space-time is a fundamental concept. But Greene thinks there might be something ...

For more than a century in theory and at least a couple of decades in earnest, researchers have pondered the construction of ...